Bell Engineering

Bell Engineering Stage 3

[10/1/2007] Reviewed by: Andrew Cooke -

Applicable to: '90 - '97 1.8 liter

BEGI Stage 3 Turbo Kit

All the pieces looked very nice. Welds were very nice. All pieces looked like a work of art. Fit is nice, everything was delivered at the price range I wanted. Stephanie was very helpful, and any questions I had, Corky answered with no problem. Overall best experience I have had with a turbo company.

Everything went smoothly, great experience.

Difficult to remove without leaving damage

BEGI Turbo 4.2

Bell Engineering 4.2 turbo kit from Fly'n Miata

[5/15/2002] Reviewed by: Jeremy Pace -

Applicable to: '90 - '97 1.6 liter

Cant imagine this kit being put together any better! Everything is there! Just add gas! I was really pleased with the quality of the product and the fitment of everything. The kit even comes with a drill bit for your oil return line.

Takes about 20 hrs to do the job taking your time and making sure everything is done right! The directions are pretty straight foward and of Course FM technical support is there if you have any questions. Tuning of the kit is pretty simple, check your base timing, and set your base fuel press. and then your boost fuel press. and that is it. I am very pleased with the install and the kit. I have already moved the boost to 10psi and retarded the timing a little more and it feels great! This thing pulls very good. I got the Small Bearing turbo and it spools nicely, It comes into full boost at about 3200RPMS. Throttle response could be a little better, but I think With a little better timing control this can be helped. The car pulls hard to redline and sounds really cool when turbo spools. This kit will beat up most any street driven car you come up against unless they are heavily modded.

Only thing I would change is that the msd unit that comes with the turbo is not the best choice for timing controls. It pulls 6 degrees of timing as soon as you come into boost and this really isnt the best bet. I would recommend dropping the msd unit for the $150 credit and then getting the bipes ACU from roadster performance for $200. Your timing controls are now actually controllable and adjustable. Much better choice if you plan on moving the boost up ANY! You will get much better low end pull and throttle response. Remember you WILL need a new clutch! My stocker lasted about 45mins. When tapping threads into the oil pan, remember to put vaseline on the tap, all the metal shavings will stick to the tap when you pull it back out instead of dropping into the oil pan. Oh yeh, make sure you have all your hose clamps where you can get to them, as they will need to be retightened after awhile.

Difficult to remove without leaving damage

Update: [4/4/2003] Reviewed by: Jeremy Pace -

Applicable to: '90 - '97 1.6 liter

Full Turbo kit for $4000

It has been a year now and all is still great. I have added a greddy Profec B boost controller. The only problem I have had with the kit is the downpipe developed a small crack in it. Fly'n Miata replaced this at no charge as my unit was still under warranty. Other than that, The Kit has been absolutely wonderful. I Have actually been running 10-12lbs of boost very consistently with no problems. Dont I have upgraded the injectors to the 230cc 1.8L injectors with the stock ECU coupled with a Bipes ACU from roadster performance. This is a great piece for $200.

I just wanted to follow up a year into my experience and say that hey, It holds up and it holds up well!

Difficult to remove without leaving damage

BEGI Turbo 4.2

[4/3/2000] Reviewed by Chris Rummel -

Applicable to '90 - '97 1.8 liter

An 8psi intercooled turbo system from Bell engineering and Dealer Alternative.

I just got the turbo and installed it over the course of 4 days, a time consuming process made more time consuming because I do things and check a lot. The wait for this kit is killer about 8-10 weeks, but well worth it for the quality of the product and for the excellent customer service from both Bell and the Dealer alt.

I went with the 8psi intercooled kit and upgraded to the Ball Bearing turbo. The kit comes with everything needed to install, read a lot of stuff to install! I suggest that if you are undertaking this install that you contact someone who has done it for advice and tricks to making the install easier, especially if you are of limited skill.

This kit is very high quality, I put the kit on at a professional shop, and the owner and several other people commented on the excellent look and compleatness of the kit. I'm happy as can be with this kit, and the Dealer alt and Bell are both the best when it comes to customer service, if you have a problem they will work it out, as if they were working on their own car.

Aerodyne Turbocharger

[4/4/2000] Reviewed by Chris Rummel -

Applicable to '90 - '97

8psi intercooled turbo kit

I love it, great performance see below

Out of the box the turbo makes 6psi, and adjusting for the boost would be a pain, because of the actuators close proximity to the intake adaptor, this problem was not too bad for me, because I installed an aftermarket boost control from Blitz, so I did not need to mess with shimming it up with washers, just something to think about if you get the Ball Bearing upgrade.

Even using only 6psi the car really is fast now!

you can easily defeat most cars now, and I still can go to 8psi up to about maybe 10 without haveing to change the injectors.

I was considering a supercharger, but I'm glad I got this turbo instaid. It makes more power more easily right out of the box, and I can still go higher with upgrades and by changing the boost.

The system is quiet too, You practacly hear nothing, the car just goes, it is even more quiet then stock. I currently have the borla exhaust, but will have to go more free flowing to get my exhaust note.

[9/1/99] Reviewed by: Steven Daniels -

Applicable to: '90 - '97 1.6 liter

Variable Vane self-lubricated turbocharger

I've been getting hell from my roomate (who owns a Sebring'd miata) to go to forced induction for quite a while. I've been looking for over a year, and I had pretty much settled on the Aerocharger system for several reasons. First, I have a 90 Model which has the lightweight sport crank. Problems have arisen with the crankshaft, and I thought it safest to steer clear of anything that would add stress to it (like a supercharger). From there, I liked the variable vane principle. It supposedly removes quite a bit of 'turbo lag'.

The installation took me the better part of two days. The most difficult part was freeing the catalytic converter. After 3-4 hours of fooling with it we finally got it off. One of the studs was mangled, so we ended up drilling and taping a new stud into place. In retrospect, it would probably have been easier on every if I had bought a new cat. With that out of the way, the next big hurdle came from my stupidity. I was tightening one of the bolts that holds the turbo to the manifold when it suddenly gave. Again we drilled and tapped in a new stud which cost us at least another 4-5 hours. Anyway, after the crises had past, the installation went smoothly. On my drive to work monday morning after the install, I drag raced every car that had the misfortune to pull up next to me (including mini-vans, civics, and even a dump truck!). I would definitely install this kit again given my needs and no desire to push 300HP (at least not yet!).

Over 30 minutes to remove completely

Bell System IV Turbo

Reviewed by: Mike DeLuco -

Bell system IV turbo 1.6

Ordered Bell system IV turbo direct from Corky in March '98 based upon extensive research on all forced induction options for the Miata. Optional equipment included Flyin' Miata Racer Intercooler, (huge) and J&S sensor w/dual monitor. Took approx. 9 weeks to receive everything ordered which was about right (8 weeks quoted). Was fairly impressed at the quality of the kit and parts included. Was under the impression that great detail had been spent on design as the kit appreared to be fully complete and well thought out.

Professional install took about 25-30 hours (some custom placement of devices and electronics elevated this figure). Again, appearance was totally shocking, .. seeing a large turbo and red powder coating all over the engine bay is most impressive. Everything fit perfectly, (not sure if because of professional install, or not. heard of others complain about fitment problems, but not with mine.) Engine compartment looks busy now with hoses and red tubing floating all over, .. but totally awesome.

Upon driving the car, I was slightly disappointed at somewhat lack of low end power, .. but this might be expected from larger turbo versions such as this system 4. Once the boost rockets past 5psi, look out, .. and you better be pointed straight! Currently running 10psi the car is truly amazing. It idles stock, drives like stock, and still gets good gas mileage (who cares anyway?) The big improvement is total all out power,.. this thing pulls like a freight train right to red-line (I shift at 7200). I've owned many turbo cars - mostly Diamond star cars, .. the Miata turbo feels very different in its application of power througout the rev-band. A little gas will get you nominal boost pressures like 1-3 psi, but, .. a little more gas and wooosh !! It just seems to spool up and you experience a sudden surge of power.

Over all I couldn't be happier with the System 4, I have run 5.9 0-60 on a G-tech meter numerous times with 17inch street tires (stock pressure). I have walked away from Talons, Mustangs, and nearly most performance cars on the road. At 10psi, the car will run 96 mph in the quarter mile as well. Anybody wanting a fast, fun, reliable power adder for the Miata should look no further than this system 4 turbo kit.

Further performance gained by cat-delete, lightening the front end, HKS drager exhaust, + high octane fuel.

Future plans include 4 additional injectors (one per cylinder) and an additional injector controller HKS or Greddy. Boost then will be 15-16 psi on race fuel 112 octane or better. Hopefully looking for 260 h.p. at the wheels.  Drag radials and loosening the front sway bar will easily equate to 12 second 1/4 mile times.

Highly recommend this kit for anyone looking for serious power adder, or looking to further enhance upon this kit in future. Couldn't be happier with this thing. Ever walk away from a Cobra Mustang in a 1.6 liter Miata, .. the driver of the Cobra didn't think so either as I missed 3rd gear and went into 5th and still had him by 5 car lengths.

Bell System IV Turbo

Reviewed by: Albert Tong -

Below I included a description of the System IVn turbo installation, and update on turbo tuning since the turbo was installed.


The System IV is in our Miata. The total installation took about 30 hours with simple hand tools. Overall, the installation is simple & straight forward. All parts are in very high quality. Some parts of the instruction are a bite confusing. Troubles I ran into were taking the EGR tube apart, the hose that goes into the turbo inlet, the hose that goes into the Intercooler outlet, intercooler pipe rubbing fan belts, fuel leak and waste gate actuator rattle when throttle close. The EGR tube was a pain in the butt do to the location of the tube, I can barely fit any tool in there. The outside diameter of the turbo inlet were too big, I had to lube it with some soap water to get the hose to go over it. Same story for the intercooler outlet hose. The 1st and 2nd intercooler pipes were touching the alternator belt, I had to use some safety wire to pull it away from the belt. Corky Bell told me to readjust the intercooler pipes connection, and I did it twice with no improvement. The brass fittings for the adjustable fuel pressure regulator was a pain, they require superman's strength to tighten otherwise they will leak when the fuel pressure get too high. The waste gate actuator seem to be working properly, but it rattle every time when the throttle is shut and rpm drops below 3000 rpm. A new one is being ship to me right now. The total installation was simple but it takes a long time to complete. I soon will have pictures post on the web.

Driverability and Performance

The 1st time I drove the car after the installation, I didn't notice much different except for the sound of the engine being a bit higher pitch and louder. The exhaust sound is gone. The driverability is about the same off boost to 3 psi. But once it reach 7 psi around 5000 rpm, all hell break loose. The rpm climb very very fast, specially in 2nd gear. I had a hard time keeping it from hitting the rev limiter even after a week. On the freeway in 5th doing 75mph, if I crack the throttle wide open, power comes in slow, but if I ease in the throttle, I will find myself doing 90 in 4 to 5 seconds. Overall, the performance is good, top end power is very good. Mid range and low end torque was below what I have expected. A while back, I borrowed a G-tech and did a few 0-60 runs. My best time for both directions were 6.24 and 6.30. When the car was stock, it took almost 9 sec. to get to 60mph, not bad for 30 hrs of work with no other modifiation. I think with free flow exhaust and a electronic boost controller, I should crack into a 5 second range no problem, that should also give the car some torque at low and mid range. Fuel economy was very good. The 1st tank after the installation with a lot of full throttle tuning and fuel leakage, I got 20+ mpg. The 2nd tank with some normal driving I got 22+ mpg.

This is the 3rd week I had the turbo installed. Everything seem to be fine, I still have problem with the minor fuel leak at the fitting I mentioned earlier when the fuel pressure get too high. I think I need to dismount the adjustable fuel pressure regulator and retighten the fitting. I turn up the boost from 7 psi to 9.5 psi. Oh my god, the mid-range torque is so much better. In 2nd gear around 4000 rpm, I can really feel the push from the g force. Before at 7 psi, I can't notice any push at all. Mid-range and high end rpm climb really fast now. It is really cool. The engine seem to be fine with the boost set at 9.5 psi. The air/fuel mixture is running a bit richer when compare to 7psi, around 11.6-12 to 1, the ideal is 12.6 to 1 for turbo car. I do think the timing needs to be retard a bit though. At 5000 rpm and 9.5 psi the computer is retarding 16 degree. It only retard 10 degree at 7 psi. The J&S can only retard 20 degree maximum. Right now I am running 14 degree BTC at idle. I think I am going to run it at 10 degree BTC for safety. My girlfriend loves it with 9.5 psi, she said it was crazy, by giving a little gas, she find herself doing 95 mph from 75 mph in just a few seconds, it feels like other cars are parked on the freeway. I did some horse power calculation last night, the 1.8 liter motor with 9.5 psi is pushing around 220.28 +/- 5 hp at the flywheel. This about 178.43 hp at the rear wheel with 19% mechanical lost. That's with stock exhaust. Can't wait until I have a free-flow exhaust put in. It should add 10- 15 hp to the 220.


Reviewed by: Jim Barrick -

It took about 3 months to receive the kit. So much for 7 wk delivery promise. Large intercooler, larger RC injectors, 12lb. boost / with dial-a-boost option. Also have BEGI Large downpipe and complete exhaust.

Materials are of decent quality. The Turbo flange does NOT come with a gasket and mine leaks. However, Corky sent me a new one. It will need some maching to guarantee a tight seal without a gasket. The installation was pretty straight forward. I have access to a full shop, with air tools and it took about 30hrs. to install! I am slow and methodical, though.

My 1995 goes like stink up to about 5500 rpm, then the halmeter shows dead rich and the car falls flat. Seems the fuel regulator is over boosting fuel (larger injectors). With the accelerometer the stock HP was 107. Now running 190 HP SHIFTING AT 5200! This thing will be very,very scary when I get the fuel management problem solved. I have found nothing on the road that can out accelerate this car to 60mph. Short shifting still gives me a sub 5 sec. 0-60!

Follow up:

Well I still can't get the fuel management systems to work right. Either I have the low and mid range ok and it falls flat on it's face at 5500 rpm or I can adjust the high end to run ok and the mid range throttle response is as though the engine swallowed a chicken bone.

Bill at Flyin' Miata was very, very helpful. Even though I purchased my turbo direct from BEGI. Corky or Jeff at BEGI don't seem to have a clue as to what is going on. I am convinced that to run higher boost levels (above 10psi) a programable ECU is the going to be the only way to achieve the full potential of the system. Plus, according to Bill at Flyin' Miata, you can get rid of the extra fuel pump, fuel regulator and knock sensor. That sounds good to me. I do wish BEGI had experimented with 1.8L at higher boost levels in order to get their fuel regulator to work properly.

We have tried every possible combination of boost bleed, restrictors, etc. Now I can't wait to Flyin' Miata gets their Programable ECU on the market. I know there are at least 40 more HP lurking under the hood of our little beauty.

BEGI Aerocharger

Reviewed by: Christian Andersen -

Intercooled Turbocharger (Kit included Turbo, Intercooler, Headers, Boost Gauge, K&N Air Filter), HKS Cat-Back Exaust, J&S Knock Retard System, Walker Super Catalytic Converter, Centerforce Clutch, Magna Core Spark Plug Wires, Total Cost $5000

The Kit was installed by Mech Tech Motorsports in Escondido, CA. My initial impression of the kit was elation and joy. The car drove like a charm, neck -breaking acceleration. Unfortunately my elation ended 11 months (20.5k Miles) later. This was about the time that the car was going in for it's 20-25k checkup. After driving the car on the streets only with only 1 road race early on, the turbo self-destructed. Due to my proximity to Mech Tech (I was in Tucson, AZ at the time), it was three weeks before I could get the turbo removed and sent back to Aerodyne (Corky Bell at Bell Engineering wanted nothing to do with responsibily for this situation, but was otherwise helpful). After it was sent back to Aerodyne (in the hopes that it could be repaired), Aerodyne informed Mech Tech that they could not fix the turbo and could not determine the cause of failure. Needless to say I had to get the turbo replaced, at a cost of $1200 + $300 intallation + $100 shipping (that Aerodyne/Mech Tech had stated they would pay but in the end didn't pay it) + $189 Inital Tune Up (the car ran extermely poorly after the turbo was replaced and Mech Tech was in too much of a hurry to fix it correctly the first time) + $249 Follow Up Tune Up (hey, third time's a charm) + $200 Oxygen Sensor (the heat of the turbo damaged the original one) + $800 (!) Mass Air Flow Sensor (the broken turbo damaged the orignal unit) + $250 Turbo Extended Warranty (Aerodyne couldn't see there way clear to throwing this in, despite the first unit being a lemon) and a total wait of one month (!). All in all over $3000 to repair the car!

While I am impressed and happy with the car when it's running, I would not have purchased the kit in hindsight. Mech Tech, while being very mechanically competent, as poor customer service. Bell Engineering put together a fine system, but did not stand behind their kit when it broke and instead referred me to Aerodyne. Aerodyne delivered a product that according to all knowledgeable sources have said should last 100k miles or more. Additionally, their inability to diagnose the failure and repair it brings in to question their competency and ability to deliver a quality product (in a timely fashion) that they stand behind (without the need to charge an additional $250 for an extended warranty that was previously unavailable when I initially bought the kit). Instead, I was left holding the bill. I would like nothing more than to ask all who consider such modifications to BEWARE! Please reconsider before purchasing this kit!! While it was once fun to drive, I am leery to drive it for fear that it may get damaged once again....

BEGI/Team ProScreen Aerocharger FTD1

Reviewed by: Lee Bohon -

Base-model Aerodyne turbocharger

It’s a bird! It’s a plane! No, it’s an Aerocharged Miata!

After about two years of "thinking about it" and saving for it, I finally made the big splurge. On March 20th, I joined the family of forced-air miatas with my most recent modification to my '91 base model miata, an Aerocharger FTD1 turbo kit purchased from Team Proscreen.

As many would agree, there are excellent supercharger and turbocharger kits available for the miata today but, there were a few final determining factors which made me decide on the Aerocharger over other systems. Probably the single most determining factor was the bang-for-buck measurement. I felt that if I were going to spend the money, I should at least try to get as much as possible for the amount I could afford. Perhaps equally as important as the bang-for-buck issue, I didn’t want to take away the great drivability characteristics that are natural to a normally aspirated miata. I wanted my miata to drive just like a normal miata... just more natural feeling power when I put my foot down. In addition, I wanted the strong power all the way to redline - traditional of turbos, while exhibiting excellent throttle response (low lag) characteristic of a supercharger. Another factor on my decision was the upgrade ability of the kit.

When I purchased the kit, I realistically knew that someday I would want to upgrade to even more power, so the ease, cost, and availability of upgrades to the kit were certainly considerations. Lastly, I was concerned about the installation of a turbo kit. How hard is the installation? Is it reversible so I can put my miata back to how it was before the install? Will I need any other items not included with the turbo kit in order to perform the installation? All of these issues were carefully considered before deciding on a kit.

The Aerocharger FTD1 turbo kit was the answer to all of the requirements. This kit is considered an "entry-level" turbo as it produces a conservative 6 psi of boost. The driveability is very smooth. The power is a nice swift push in the seat. For entry level boost, I am pleased.

Installation was certainly no harder than changing a clutch. Actually, the installation was not very difficult, just time consuming. Total installation time including a couple of hours sorting parts and carefully reading the instructions came to around 15 hours. I highly recommend having a friend help with the install especially after reading the instructions and after the parts have been sorted and accounted for.

So what are downsides to the Aerocharger? Overall, very little. Probably the only thing about the Aerocharger that I don’t like too much is the noise under the hood. It is faint, but when everything else is very quite, it’s noticeable. This is one of those things that varies from person to person. At the time of this writing, I have a stock exhaust (cat and muffler) so the sounds out the tailpipe are quiet.

Gas mileage is supposed to remain the same or go up slightly. However, with a heavier foot that "gee, somehow" comes with the turbo, aggressive daily driving has caused the mileage to go down a couple miles. No loss at all in my opinion. Certainly worth the power.

Power is contagious. I already want to upgrade to the Aerocharger FTD2 level which would put my miata around the 8.5-10 psi boost level. However, other miata upgrades are in the queue including shocks (to help keep the tires to the pavement) and exhaust (to help the turbo breathe easier!)

Please feel free to e-mail me ( if you would like to know more specific details about my experience with adding a turbo to my miata. Hopefully, I’ll have a decent write-up on the installation and more details of my turbo experience at my website in the future at: (

BEGI/Team ProScreen Aerocharger FTD1

Reviewed by: Matt Alley -

The Stage 1 Aerodyne turbocharger, as assembled and marketed by TeamProScreen

After two weeks of ownership, including 90 minutes of track time:

The kit consists of the turbo and associated plumbing, cold air induction, a hood prop rod, and the BEGI fuel pressure regulator. It is designed to run at 6 psi., but can be upgraded to Stages 2 and 3 for ~ $1000 per upgrade. These include intercoolers, larger injectors, MSD or J&S knock sensors, auxiliary fuel pump. Each upgrade is worth ~ 2 lbs of boost.

i was planning to install the kit myself, but R-Speed made me an offer I couldn't refuse, as they had never done a 1.8 before. TeamProScreen photographed the install in order to revise the manual for 1.8 installation, as currently the instructions are 1.6 specific. The manual is top notch, far superior to any I've seen so far. in retrospect, unless i just wanted to put th Miata on blocks and tinker with it for a couple of weeks, I would hire the install done in the future. It wasn't particularly difficult, only time consuming.

Initial problems when I picked the car up included a lack of low end grunt, and pinging at 5000 rpm. I found that they had set the timing to 6 deg to combat the pinging, and it had helped, but not eliminated the problem. R-Speed worked on the car that afternoon, but we were never able to kill the knock, even with the timing set ridiculously low. So we ordered a J&S. This allowed the timing to be set at 12 deg without knock.

Since the kit is sold without an electronic timing retard device, I have to believe that it can be run like that on some 1.8's, but it didn't seem possible on my car. And I've had my timing at 18 deg before with no problems. Anyway, if you have a 1.8 figure on bugeting another $130 or $400 for MSD or J&S with the Stage I. Fortunately, if you go with Stage II later, they will delete the MSD and you won't have wasted the money.

Of note: Hector at R-Speed told me to regap my plugs to .039. I put in new ones and gapped at .039, and this made a measurable impact on acceleration. I didn't write down the measurements and can't remember them, but it did help.

Driving Impressions: The turbo is so transparent if you stay off the throttle. Very smooth power delivery. i have found it to be almost an exact replica of a strong N/A car's hp and torque curves; not linear at all, but nice and rev happy. Above 5k rpm the power comes on with a rush. Nothing unsettling, but just there. At highway speeds, the feel of the engine in 4th or 5th is tremendously enjoyable. It doesn't push you back in your seat like a big V8, but there is noticeable acceleration.

At the track I ran three 30 minute sessions wide open. I have an oil cooler and oil temp guage on the car, and the oil never ran more than 210 deg, which is a little warmer than it was at the same track a month previously, but ambient temps were ~ 10 deg warmer. The water temp stayed the same as always. I was surprised and delighted by this. no hoses blew off, no pinging ensued, no fluids leaked, no strange noises emanated from beneath the hood. And after the first 5 or so laps, when I had learned the new braking points for my slightly higher terminal speeds at the end of the straights, everything was just as before. The power didn't upset the car's handling at all.

I am very pleased with both the product and the installation and support of R-Speed. It is a great wat to start in the world of turbos, and a great place to stop if you don't want mind numbing power. The car feels like a good factory turbo car from the Japanese. No complaints at all, now that the J&S is on and the tuning is done.

BEGI System III Turbo

BEGI System III Turbo (modified)

Reviewed by: Barry N. Birdwell - bbirdwell@swri.edr

Warner-Ishi RH-B5 water-cooled, oil-lubricated turbo with intercooler, rising-rate fuel pressure regulator, and MSD ignition retard.

System was originally installed by Corky Bell on my older 91 Miata in September 95. After 11,000 miles I transferred the system to another 91 Miata on which I have accumulated an additional 11,000 miles. I transferred the system to the newer car in one day, without instructions or special tools (I am mechanically inclined). After the initial setup, the system has performed flawlessly. Corky rates the stock system at a max 10 psi boost because of limitations in the stock fuel system. I was able to consistently run a max of 9 psi without detonation or "lean" conditions. After talking with Corky, I installed larger fuel injectors and have since increased the boost to 12 psi. After 22,000 miles, I have had NO problems with the system. The stock clutch has a very limited lifespan with the turbo. Mine lasted approximately 6000 miles before I administered the "coup de grace" at the dragstrip and replaced it with a Centerforce Dual-Friction clutch. A high-flow exhaust is required to get maximum benefit from the turbo.

I strongly recommend this outstanding system. Acceleration is smooth but vicious and almost scary. This turbo kit is worth every penny. Fit and finish of the kit are excellent. Professional-looking installation that looks as though it was installed at the factory. Corky Bell is a pleasure to deal with.

Update by: Barry Birdwell -


I’m submitting this to provide an update on my BEGI System III after 21 months and 42,000 miles. System is running beautifully. Total work performed on the system to date:

  1. Water hoses became brittle where they attach to the turbo. I trimmed approximately three inches off the ends and re-installed.
  2. One of the turbo intercooler line connections popped loose under full boost. This was because I failed to tighten it properly and I failed to check the system.

“Fuss factor” of my system is virtually zero.

Several people have asked me what is involved in “dialing in” a BEGI system. I would like to make the following suggestions and observations. Please feel free to provide tips and tricks to me if you have them.

What does setting the operating parameters of a BEGI System involve??

You need access to a level road or runway or some large area where you can make repeated runs. I recommend having an assistant so the two of you can share reading boost gauge, fuel pressure guage, fuel/air ratiometer (recommended, or use a DC voltmeter during dial-in to save money). The fuel/air ratiometer (or voltmeter) helps you to determine the richness/leaness of the mixture under full and partial throttle. You need to verify fuel pressure at idle and max boost. Repeated "tweaking" of the fuel pressure regulator, waste-gate setting on the turbo, and the J&S ignition retard sensitivity adjustment is required. (I strongly recommend the J&S. Get a credit for deleting the MSD.) What adds to the frustration level for a new owner is the way the parameters are all inter-related. Hints:

  1. Generally, your max fuel pressure will be in the neighborhood of 100 psi.
  2. For max fuel pressure you need max boost on the turbo. But, Catch-22, you cannot run max boost on the turbo until the fuel pressure is high enough. Solution, set the fuel pressure too high to start. Set the boost. Go back and adjust the fuel pressure down. For a standard System III, set the max boost to approximately 9 to 9.5 psi in 4th gear. (From my and others’ experience, even at 100 psi fuel pressure, 10 psi on stock injectors is pushing the engine close to lean conditions).
  3. Now, the max boost affects the max fuel pressure but the boost varies depending upon engine load! This boost variation is called "boost creep" which occurs because of the pneumatic-mechanical design of the wastegate on the turbo. In my modified System III, I get approximately 10 1/2 psi in 1st and 2nd gear, 11-12 psi in 3rd, 12-13 psi in 4th, and 13 psi in 5th. Boost creep can be eliminated by going to a computer-controlled wastegate but, for $600, that's a bit steep for me and I'll stick with the standard system. The point I am trying to make is you need a long run to set the boost consistently (i.e. always go for 9 psi in 4th gear, or 8 psi in 3rd gear.) Don't set the boost for 9 psi in 2nd because you're going to get 10 psi or more in 4th gear and endanger your engine. Try to run in similar conditions to reduce the variables.(i.e. temperatures consistently in the 70's (or 80's, or 90's), not one day in the 70's, the next day in the 90's). Set your max boost in the same gear every time you adjust it and preferably on the same level stretch of pavement (you'll get different loads if you run uphill one way and downhill the other).
  4. You also have to set the sensitivity of the J&S. Too sensitive and road noise will cause it to retard the timing unnecessarily. Too little and you will get more detonation (very, very bad). With a J&S I will hear a cylinder "ping" once and the J&S retards the timing to that cylinder before it can happen again. Maximum of 4 pings (one per cylinder) seems to be what I get. To set the J&S, drive down a level road at constant throttle and have a passenger increase sensitivity until you feel the engine "bog" (it's very subtle so do this where you will not be distracted by traffic or cattle). The passenger should then decrease the sensitivity above that magic "road noise" point.
    That's what I did and I still didn't get it right. ;-)
    My car ran fine on level roads but not when accelerating lightly! Full-throttle was fine. Under partial-throttle acceleration my car would buck and kick slightly. What gives? Seems I forgot that an engine creates more noise and vibration under acceleration and load. This increased noise was above the "road noise" point and triggering the timing retard (hence the on/off "bogging"). I decreased the sensitivity a little bit more and "Wow!", it worked. I think of it as the "road noise plus part-throttle acceleration" point.
  5. You will also be checking for loose connections, hoses, clamps, rubbing, or leaks. When you finish the install, take a break. Then come back and go over *everything* you did. Have a friend check your work behind you. Check constantly in the beginning until you are confident you have not missed anything. On one install of a System III, my buddy was ready to drive out the door with his new toy (it had been a long two days). I had him stop while I checked the install with the engine idling, and, sure enough, I found two fuel leaks where we did not tighten fittings properly. A extra 30 minutes of work to fix, but cheaper and easier than cooking marshmallows over a flaming Miata.
    Take your time! Double and triple-check.

What types of skills and adjustments are required to set the system?

You will need a hex wrench (allen) to set the idle fuel pressure, two open-end wrenches for the waste-gate adjustment (I believe they are 10 mm), and a small flat-tip screwdriver for the J&S. Your fingers are needed to adjust the needle-valve on the FPR to set the max fuel pressure. Leave the heat-shield off of the turbo while adjusting the boost or you will have to remove it every time to get to the waste-gate. Bring leather gloves; it gets HOT under the hood and my turbo has cooked the hair off my hand when I got too close to it. Get the system dialed-in and get the heat-shield back on it. With the J&S, clamp splices are provided for tapping into the electrical harness. I recommend soldering the connections. You do not want an intermittent connection a year from now. Paul Turing at Berkeley sent on a good idea of wiring in the J&S close to the Engine Control Unit (like 6"). I soldered mine into the harness under the hood and had to drag six wires (about 7') through the firewall. Some soldering skills (or a friend with them) are a big help.


First-time turbo owners worry about the new noises coming from under the hood. Some noises to expect:

  1. A very quiet high-pitched whistle that varies in pitch. This is caused by the turbo spooling up and down and can only be heard under certain throttle conditions.
  2. A low "whoooosssshhhh" sound when you close the throttle suddenly. This is the pop-off valve releasing the pressure from the intercooler tubes to prevent "compressor stall". Compressor stall occurs when the fast-moving airstream in the intake tubes slams into the closed throttle-body plate and bounces back to the turbo where it bounces back to the throttle plate where it bounces back again, ad infinitum. On a car without a pop-off valve you can hear this as a sharp "brprprprp". Compressor stall will not damage the turbo but it slows down the turbine wheel. This means you lose power and time as the turbo spools back up again.
  3. Even with a J&S, you will occasionally hear some pinging. The J&S will not retard timing until it senses the onset of detonation (it can't foresee the future). These first pings that trigger the retard are what you will hear. They should not be continuous but rather should quit within a second or less. Run the tank low on fuel and fill with premium. Run premium for several tanks before installing the turbo. Low octane fuel defeats the purpose of setting the sensitivity on the J&S.

I recommend two options when you buy a System III.

  1. Delete the MSD for credit and buy the J&S.
  2. Also, purchase the new 2 1/4 " downpipe that goes from the turbo to the catalytic convertor. It's a huge tube and eliminates the restriction of the stock pipe feeding the catalytic convertor. The base System III exhaust downpipe only goes from the turbo to the triangular-shaped junction (next to the bell housing) on the stock exhaust. This leaves a 1 7/8"(?) diameter tube with crimps in it between the turbo and your nice, high-flow exhaust.

I hope this helps someone out. I am enjoying my System III+ immensely. Puts a smile on my face after a long day at work and makes the back roads of the Texas Hill Country a blast to drive.

Barry Birdwell

Reviewed by: Geoffrey Sharples -

Turbocharger, Larger Intercooler, Larger Injectors, MSD Ignition Retard

Questionable material (the crinkle coat on the header was flaking off when product arrived). Had to replace fittings for fuel pump due to poor quality. Still waiting for the rest of the parts after 19 much for the 7 to 9 weeks they advertise!

It's unfortunate this forum does not allow a review of customer service, I could write a very spirited one. In hindsight, I wish I had spent my money more wisely. There are several shops that offer custom made turbochargers here in Southern California that deliver what they promise. Here is a partial list:

Bill Craddock Enterprises (909) 305-8678
RC Engineering (310) 320-2277
Top-End Performance (818) 764-6768
Turbonetics (805) 529-8995

BEGI Autorotor

Reviewed by: Charles Fearneyhough -

Supercharger for the 1.8l Miata

Installation of the BEGI Autorotor Supercharger.

I ordered the Begi Autorotor on 5/1/96. It arrived on 7/30/96, 13 weeks. The kit is of high quality. All of the parts were well made and had a good finish. I ordered the SC with the J&S knock sensor, it came with it.

Trying to decipher if I had received all of the parts was a bit of a challenge as only the cast parts have numbers on them. As it turns out I was missing a few items. The box had broken open in shipment. The parts I was missing were shipped the same day I called Begi and I received them the next day. Corky is very responsive to this kind of thing and will do everything possible to amend the situation.

Tools Required:

There are a few tools not listed that I found very helpful:

Removal of all of the equipment off of the motor is straight forward. No problems there. Drilling and tapping the oil pan is no big deal. I found it to be easier to remove the power steering hose from the axle. This gave me enough room to drill the hole straight using a standard 1/2" drill motor.

Installation of the fuel pump was pretty easy. The only question I had was the routing of the fuel line from the pump. I ended up looping it above the Power Plant Frame. This gave it enough room not to kink. When installing the plate that the SC bolts to the lower bolt flange conflicted with the exhaust manifold. I trimmed the flange with the sawsall and filed it smooth. The heat shield was a bit of a struggle, have plenty of Band-Aids ready for when you trim it and have to reinstall it. The section I trimmed off I reattached to the heat shield to further protect the power steering hose that is turned around and now lives very close the exhaust manifold. This may prove to be a source of noise, vibration, if it gets loose, time will tell. I found it easier to place the heat shield in place but down lower on the exhaust pipe and not bolted down before installing the SC. Trying to finagle this shield in place after the SC is in place would be a real challenge.

Installing the SC was a challenge. The instructions call for the casting to be true to .002"!! That's real true!! After getting it as true as I could I bolted the SC in place. The top three bolts are a no brainer but the bottom two??? Now comes the 'wacky' wrench!! I customized two wrenches, bending them this way and that until I had something that would reach these bolts. I broke the first wrench trying to bend it into the right shape. The second wrench ended up being very short and finally worked. These two bolts are REALLY difficult to get to, at least for me. You just have to take your time and you'll get it.

The powder coating that is applied to the casting gets into the threads. You will need to chase these with the appropriate tap.

That's really about all the trouble I had installing the kit. Just follow the directions and its not too bad.

Total install time approx. 25 hours.

I have 1000 miles on the SC now with no major problems. As you can imagine acceleration is greatly improved. The car is very quick. It's still a 4 cylinder but its the fastest 4 cylinder I've ever been in!

Minor problems:

When I had completed the installation of the kit I found that the hood wouldn't close right. I discovered that the power steering fluid reservoir, in it's new location, conflicted with the plastic piece that surrounds the drivers side head light opening. I cut off the top of the cap, there is an extension on the cap that is a couple of inches high, and this fixed the problem. I probably could have relocated the reservoir to achieve the same end result.

The SC drive belt ran to the inside of the idler pulleys. I remedied this by having the idler pulley spacers turned down .070". I have a machine shop at my disposal so this was far easier than moving the SC and having to deal with those two pesky nuts on the bottom of the SC!

The idle has to be set pretty high. When starting from a cold engine it idles just fine but if you turn off the engine for a few minutes and then start it, it won't idle until the engine has ran for a bit, 2 - 3 minutes. This was solved by raising the idle to 1000 - 1100 Rpm's. But......If I turn on the headlights it does it anyway. I think I've solved this by raising the idle at little further, 1100 - 1150.

As you can see all of the problems I encountered where very easy to overcome. This is a very well thought out kit and at completion looks and is, in my opinion very professional, I am totally satisfied.

I would strongly recommend this kit to anyone who wants a system that can be upgraded, modified for even more performance. As the kit comes with the need fuel pump and regulator and intercooler your already half way there!! The whipple SC, I've been told, is very dependable.

Charles Fearneyhough
1995 1.8l Miata
MCA Member

Bell Engineering Autorotor

Reviewed by: Shiv Pathak -

A few months ago, my brother and I installed the Autorotor in my very low milage 94R. Having experience installing his Bell Warner IHI turbo, my brother was a big help in the installation. Looking back at the work, it really wasn't that hard. True, it wasn't entirely "bolt on", but we expected that. The directions were excellent and the whole process took about a week of sweating away after coming home from work.

First, you have to remove most of the intake plumming. This frees up a lot of space (I didn't know the 1.8 engine was so small. I could see how people manage to shoehorn a 5.0 V-8 in there! The next several steps involve preparing and mounting the autorotor to the egine block. Eventually, you mount the intercooler and all associated piping. Then you install the pullies (crankshaft and idlers). Lining them up is a real pain and might involve some creativity. If the pullies are not lined up, you will chew up a belt a week (as I did for the first month!) Rerouting the fuel and oil lines were a bit intimidating but didn't take too long. The new fuel pump and regulator was also a relatively easy install. We also installed a J&S Safeguard knock sensor (which is an excellent device) instead of the MSD unit. Installing the knock sensor was rather staightforward. The optional monitor is also very helpful during the tuning period.

On a late Wednesday night, we finally got everything running (to our surprise, it actually started up!!).

The first thing you will notice is the sound of the whole miata experience. The exhaust becomes louder and deeper (even with the stock exhaust I had at the time.) At idle there was a good deal of belt noise (which mostly went away as the system broke-in.) Overall, the sound is rather "unstock." Nice but very different.

Driving impressions:

For the first few miles, we were very gentle with the car to get things to warm up and to hear if anything fell out of the car. After 10 minutes, nothing fell out and we decided we were good to go. Expect to spend some time learning how to adjust the few pressure correctly. There are two adjustment screws on the regulator that you WILL become very familiar with. A poorly adjusted fuel system will degrade throttle response and power and make your Miata feel generally unhappy and sluggish off boost. After a week of fuel pressure tweaking, belt tightning, and knock sensor adjusting, my Miata started to feel great again. Revved freely, sounded nice, and pulled like a bull from 2k to redline. In fact, I liked the power so much, that I ordered new pully sizes to raise the boost from 8.5 to 10psi. If you want to do this also, make sure you order the larger optional intercooler (two regular intercoolers fused together.) This is necessary if you like your engine and enjoy having some type of margin of safety.

Driving impressions at 10.5 psi of boost:

Sheesh. A friend of mine who has a Testarossa drove my car and said it had so much torque arcoss the band it was ridiculous. Cruising around town (30-45mph)in 5th gear is habit now. Casual shifting occurs at 2000-2500rpm. With the increased boost levels, I get 2-3 psi more boost (+20 to 25 hp) at every rpm than the stock 8psi autorotor. This means 4 psi at idle and 8psi at around 2000 rpm. Much more low end and midrange torque than my brother's System III turbo (also 10-11 psi of boost). Top end is comparable (with an edge going to the turbo.) Pulls harder than the varius Aerodynes I've been that have been running 8-9 psi). All owners of other Bell systems I've talked to agree that the autorotor is the most drivable of the systems. Punch the throttle and voila.. instant boost and a firm push into the back of the seats. The accompanying turbine like wheeze (as Andi Goltz put it) of the engine on boost will have other miata owners following you for miles just to ask you was you have under the hood. "A supercharger" I respond suavely "Oh, one of those Sebrings, right?"

"No," as I spin my tires in 2nd gear and look like a complete jerk at the next stop light. Expect a lot of humiliated Corvette, RX-7, and Mustang owners point to your hood and give you thumbs up. Or if in LA, pull out gun and start shooting at you.


*0-60 in 5 seconds (4.5 sec if reviewed by the optimistic testers at Motor Trend ;^)
*1/4 in mid 13s (I did 13.9 with a bad shift, on overinflated street tires, in 102 degree weather during my
first attempt at drag racing.) Low 13s with drag slicks seems very realistic.
*50-70mph (5th gear) in under 5 sec.
*Really impressive sounding whine under boost.
*Excellent fit and finish.
*Bountiful and drivable torque at all rpms.
*Easier to drive fast than a turbo.
*Much more powerful and enjoyable than the Sebring


*Gas milage will suffer. Expect 20mpg in city, 24 mpg on highway.
*Noise. Although most people will like it, some, like my brother, will find it too load (especially with a free flow exhaust. I too feel ear fatique after long highway trips. My ears would be happy if I had my stock exhast again.
*Servicing. Expect a Mazda mechanic to stare blankly at your engine when you bring it in for a oil change. In all fairness, most of your car would still be honored by Mazda for warrantee work. In fact, I recently thought I needed new lifters and Mazda said they would still cover my car since HLA and lifter problems dould not have been affected by a supercharger. The same applies to suspenstion, exhaust, electrical system, etc,. Just don't expect them to warrantee your clutch (which you will go through in a few days).

Needless to say, I have not regretted installing the autorotor. BEGI and Bill Cardel (whom I ordered everything through) are very supportive.

My entire system costs:

$3000 kit
$150 bigger intercooler
$300 Replace MSD with J&S Safeguard
$430 Centerforce Clutch
$3850 + $300-$1000 for free flow headers/mufflers/etc,.

Not cheap, but less expensive than an RX-7 or a Supra.

Back to Product Reviews 25 November, 2007