Aerocharger Turbo Kit by Bell Engineering Group

My old system... no longer installed.  I now have an FM3 system.

After about two years of "thinking about it" and saving for it, I finally made the big splurge. On March 20th 1998, I joined the family of forced-air miatas with my biggest modification to my miata so far, an Aerocharger FTD1 turbo kit purchased from Team Proscreen.

As many would agree, there are excellent supercharger and turbocharger kits available for the miata 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 I can for the amount I planned on spending. 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 (no lag) characteristic of a supercharger. Another factor on my decision was the upgradeability of the kit. When I purchased the kit, I realistically knew that someday I may want to upgrade to even more power, so the ease, cost, and availability of upgrades to the kit was certainly a consideration. Lastly, I was also 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 6.5 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? Probably the only thing about the Aerocharger that I don't like too much is the spool-up and air-rushing noise under the hood. It is very faint, but when everything else is very quite, it's noticeable. This is one of those things that varies from person to person.

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.

After about 11 months of use, the turbo really was getting noisy, so I sent it back to Aerodyne for inspection/repair.  They sent me a brand new unit... except the new unit was Dead On Arrival!  Oh, what a disappointment.  I installed this unit and within the first 5 minutes of use, it was dead.  I immediately sent it back.  This time I was sent another brand new unit (number 3) and I was back on the road.  Ironically, it seemed that the noise that I had in turbo no. 1 was pretty apparent in this unit, but since it ran and I was tired of pulling it off, I lived with it.

Power is contagious.  I eventually decided to venture into upgrading the system.  I was lucky to have found a used "racer" intercooler for sale that was not in real good shape, but with a little work, I could have it standing tall.  The IC arrived with chipped red paint as shown below:

With a little paint stripper, and a trip to my friends house for some fresh powder coating, this intercooler really cleaned up (sorry, can't find a pic, but it was a beauty!)  Along with the appropriate pipes from BEGI, I was able to plumb it up.  After that, I added shims to the turbo actuator to increase the boost to 9psi.

Shortly after that mod, I came across another deal... this time for an FM ECU Mk1.  This unit doesn't have boost control or knock sensing, but since I had a J&S knock sensor, and the Aerodyne needs no boost controller, it was a good match for me.  The new ECU came with 370cc injectors.

Along with the exhaust modifications, I was able to reach a maximum of 193 horsepower & 165ft-lbs of torque at 10psi.  To see my Aerodyne equipped miata on a dyno, click on the links below (that's the dyno operator in my car):



Not long after this point, trouble really started to surface with the Aerodyne system.   

Here's a note I sent to Kurt at PBC a long time ago explaining the details of problems I had.  I'm posting this as is but will later clean up this note for the website...

I originally purchased a 143/300 Stage I "Aerocharger FTD1" from Don Cuniff through Team Proscreen and installed it in March of 1998. It came with a 12 month warranty, and is basically the same kit PBC sells as a stage 1 (except it had no fuel pump... didn't need it at 6psi of boost... and I always had plenty of fuel per my A/F ratio meter). Over the first 11 months of usage, the turbo got louder and louder. It was making more of that impeller imbalance noise. Also, compared to another Aerodyne turbo system I had the opportunity to experience (on Daryl Dunahoo's miata... of which the system was sold to John Gassett), my turbo made much more air rushing noise as initial boost was beginning to build. Quite annoying during normal in city driving. At month 11, I contacted Gerhard to ask him about the noises and he agreed to have Aerodyne to look at it. I shipped this turbo to him (Team Proscreen was out of business at this point).

Gerhard arranged for me to receive a BRAND NEW 128/250 unit in place of my suspect 143/300 unit. I was thrilled! So, this #2 unit was shipped to me shortly after they received my original unit. Gerhard also noted that there was evidence of motor oil contamination on the compressor side, likely due to the cam cover vent line that is plumbed to the compressor intake pipe. He suggested I install an oil separator or remove the line somehow to prevent oil vapor from getting there. So, I plugged the small threaded hole where the vent line was connected and installed a small K&N filter on my cam cover. This obviously was a preventive measure and made no noticeable impact on performance. Recall at this time I still had the stock ECU (so in theory, my engine may have run a hair more rich but I don't recall noticing that).

The #2 turbo arrived and I carefully installed it. The initial drive was very careful and gradual on boost build. Well, about 5 minutes into the drive, everything was warmed up and I began to use a little boost. The very first run with full boost was incredible! MUCH better than before. The turbo was very quiet. Very little air noise, no imbalance whine. Even the onset of boost seemed much quicker which I believe is due to the smaller 128/250 size. Within a minute of the first boosted run, I began to hear a faint noise which sounded like a goose. Still, carefully I proceeded to test the boost some more. The turbo would make a brief goose sound yet still produce boost. Over the next couple tries of boosted 0-60 runs, the goose noise grew worse, much worse. After a total of 10-12 minutes of driving, the goose noise turned into more than just a noise. When the noise would happen, there would be no boost. The boost gauge would read 0psi while the turbo would just moan. The turbo was failing. I crawled home and left the car in the garage overnight. The next morning (after all was cool again), it drove fine... for the first 5-10 minutes. Then it was a repeat of noise and failure. Keep in mind that during this entire time, I had not touched the actuator.

I contacted Gerhard and told him about the noise. I tape recorded the noise and sent the tape along with the turbo back to Aerodyne. I spoke with a technician there and he was puzzled after hearing the tape. I never did understand what exactly went wrong with the turbo that made that noise. Gerhard once again agreed to send me a new turbo. So, #3 (still configured for 6psi) was sent to me.

I installed turbo #3 and all was fine. It was still a bit noisy like turbo #1 but it worked fine. I was fairly pleased. Gerhard and Aerodyne had been very good to me.

After about 4 months of use of turbo #3, I purchased a used FM ECU. To make the FM ECU work, I had BEGI make a pipe to replace the MAF (it is one piece that goes from the air filter to the compressor inlet... 2.5" pipe the whole way). To be honest, the car seemed to run about the same as before, if not a little worse. I spent a little time tuning it (which I'm still doing) and it is better.

After about 5months of turbo #3 (1 month after FM ECU), I bought a used Racer intercooler. I bought the two unique pipes to plumb it in from BEGI. I also bought a "8, 10, 12psi" shim/spring kit from BEGI. I installed the shim/spring to get 10psi max. Everything seemed to work just fine. I drove the car for a few weeks no problem. I then drove to Deals Gap (about 4.5 hours away) and did a lot of spirited driving. While I was there, I thought I noticed a faint whine under the hood so I began to get worried and backed off of the throttle-happy driving a bit. Stephen Daniels went for a ride with me when I first noticed the noise. It was very hot 100+ degrees.

A couple days later after I returned from the trip, I was accelerating at full boost (10psi) and the turbo seized. I think it was due to a leaky BOV. I contacted Gerhard to let him know it failed and that I wanted them to look at it (sort of expecting to pay for a repair). Gerhard once again took care of me. I sent him the turbo, they dismantled it and found that it had over-rev'd ("redlined") big time and yielded the compressor wheel into the housing. Gerhard agreed to send me a new unit, but I told him that I was wanting to look at higher boost... 11-12psi. He sent me turbo #4 with the new actuator and billet backplate.

Turbo #4 arrived and there was a configuration problem. The actuator pointed down, the compressor/oil reservoir protruded out 1 inch than my other units (it was the 118cc size instead of 65cc), and the compressor outlet pointed in a 12:00 direction instead of 11:00. All three variables were wrong. No big deal; Gerhard said they would reconfigure it all and send it back to me in the same day they receive it back from me. Before I shipped it to them, I went ahead and installed it. Yep, despite the configuration errors, I rigged it up so that it would work. And boy did it work! A bit noisy on the air rushing noise, but boost response was great and holy cow, 11psi feels GOOD (it actually went to almost 12psi). I had to try the new actuator so that's why I installed it.

So, I took the turbo off, sent it to Gerhard and once again, they sent me a new unit (instead of reconfiguring turbo #4). I don't know why but that is what happened. I installed turbo #5 and upon initial startup in my garage (not even for a drive yet), I heard the same noise I heard on turbo #2 when it began to fail. It was VERY faint and brief, but I could rev the engine and hear the noise. I drove the car anyway and it performed great. However, the noise was there every time I took off (about 5-15 in Hg vac). It grew worse over 2 days and on two occasions, it quit working entirely - except would make the goose noise. I could not believe it. In fact, I figured I had something vibrating somewhere due to my installation. I just could not easily accept the idea of the turbo having a problem again based on probability. I checked everything over. Could find nothing so I called Corky this time. Corky has told me before that he has never experienced a failing aerodyne. Because I wanted to verify that the turbo had a problem, I asked Corky to install the unit on his car. He agreed and sure enough, he experience the same symptom. So, the turbo had a problem.

Corky sent the unit to Aerodyne and I believe they have sent another brand new unit to Corky. They want Corky to verify it is good before I install it on my car. Gerhard made a very good point with me that they bench tested the turbo #5 before they shipped it to me, just to make sure. When I told him I suspected a problem, he was in disbelief. Due to their testing prior to shipping to me, Gerhard suspects that something else (either my kit, my car, or me) is the cause of the problems. But, no one can figure it out. The thing is, I drove with John Gassett's turbo for weeks with no problems. I drove turbo #3 with no problems for 6 months until it died but I think it was a BOV problem resulting in a failed turbo. Turbo #1 was just noisy and too big (143/300). Turbo #2 seemed to have a major problem right out of the box and so did #5. Turbo #4 was just configured wrong; it worked fine for the week or so I ran with it.

Right now, I feel I am hanging by a thread w/ Aerodyne. Gerhard has greatly impressed me with his patients and commitment to getting me a working unit but I feel I cannot expect anything more from Aerodyne in terms of repairs for the same customer. He has simply gone out of his way to help me, but I don't expect he will be eager to fix anything in the future. In a way, I've "worn out my welcome", for lack of better words.

When I get turbo #6 back from Corky, it will be configured for 8psi. I am planning on selling it as a "stage 2" kit (with the pipes for the MAF sensor) but the new owner will need to either buy a Pierburg pump (and MSD or J&S) or FM ECU, injectors, keypad, etc...

I highly expect that this turbo will be just fine. The new controller appears to be a big improvement. 8psi should be a very safe operating level without risking the turbo. However, I am wanting to be able to boost all the way to 15psi. This is the maximum for the Aerodyne turbo per its design spec and based on my history and situation with Gerhard, the idea of having another failure would not be a pleasant situation for either myself or Gerhard.

So... the reason why I'm selling is a little complicated. I want to be able to run high boost without having to worry about the turbo. I can't afford the risk of another problem. My plan is to go the Garrett route. As I'm sure you would agree, it is more suited for the high boost I want, but at the expense of low end response. I wish I could do it with an Aerodyne but I realistically cannot take that chance. It is inspiring to hear from you that you are wanting to try 14psi... but in my shoes, that scares me to death. I just hope it works fine for you, I really do. It would be absolutely wonderful to have all of the Aerodyne benefits and still have FM II kind of boost levels.

So there you have it.  I sold the system and eventually bought an FMIII system.