The Peter Farrell SuperCars installation
First, let me say that I don't have any affiliation with PFS or receive anyspecial pricing or discounts. :( I first learned of aftermarket upgrade modications that would increase the stock HP of 255 to 360 in Autoweek magazine. Well, you can never have enough horsepower. Although I had given up on "turning wrenches" over 15 years ago, I decided to take on this task as a project and educational experience. If you have an RX7 (or other modern sports car) and are considering doing the same, this narrative is for you. A 360HP RX7 is a highly tuned vehicle and there are many ways you can trip yourself up in this process. My "safety net" on this project was my Dallas, TX friend Paul Ward, an ex-master Cadillac mechanic that gave it up several years ago for a job in telecommunications. His support was invaluable. When things would get a little tough, I knew he could figure it out.WHY PFS?
Although there are quite a few options available, I decided to go with Peter Farrell Supercars (PFS) on the major mods for several reasons. First, since I was doing it myself I felt that a turnkey system from one provider would be the easiest to get up and going. If something didn't work, they couldn't blame it on "the other guys" component. Second, PFS has sucessfully raced the cars with their modifications. If it works for them, it should work for me. The last reason was geography. Their location in Virginia is closer to Atlanta than California or south Florida. If need be, I could take it to them to fix it.Exhaust System.
This was the first and easiest modification you can do to the car. It is the least costly and provides immediate, noticeable results. Although the stock exhaust is extremely quiet, it is restrictive and robs horsepower as a result. The PFS catback exhaust system is 3" stainless with a 4" polished tip. As both catalytic converters are still in place, the mod is 100% street legal for emissions. In less than one hour this install was accomplished using standard jack stands. As a result the car has a nice mellow tone and is beginning to breathe a whole lot better!Intake & Intercooler.
Now it was time to get serious. If you want more horsepower, you need more boost from the turbos. If you want more boost, you have to get the intake air temperature down by using a larger intercooler and an outside air source. Although the PFS air intake system and the PFS intercooler are separate components, they needed to be installed at the same time because the air intake plumbing shares the ductwork that feeds the intercooler from the front of the car. The new intake system uses a K&N air filter which provides the required higher air volume. Installation requires removal of the stock air box, stock intercooler, moving the air conditioner dryer and various minor plumbing, and cutting/rerouting of air lines that connect the air box, air pump and turbos. Although PFS provided adequate instructions, this one looked a little "sticky" so I decided to have Paul provide assistance and moral support during his visitfrom Dallas. The install took about 3 hours and was totally uneventful, which is the way I want it to be. Upon completion this mod resulted in an improvement in acceleration, particularly on the top end.PFS POWERTRAIN MANAGEMENT COMPUTER (PMC)
Although installation of the computer system was easily performed within an hour, for various reasons the work ended up going beyond the initial procedure. The systemconsists of a programmable add-on module, wiring harness, and 3 position switchfor Low, Medium, and High settings. The module comes pre-programmed for boost,fuel, and timing settings to deliver 300, 330, and 360HP, respectively. The installation couldn't be easier. Remove the passenger kick panel, plug inthe wire harness, stow the module under the carpet and mount the 3 way switch and it's done.The first test drive indicated that this was the main reason for doing all ofthe other modifications. It wasimpossible to not notice the power change. However, in short order the car startedto lack power. Also, the boost gauge was showing only 8-9PSI maximum on all settingswhich would make you think there was a boost problem. After determining that theboost problem was a faulty boost gauge, the power problem was determined to be the stock plugs were fouled. After replacing the plugs with colder plugs (10.5 leading 9 trailing), the power problem was solved.
Within a week, I noticed a hissing noise under load and suspected a boost leak or a vacuum line had blown off. John, the PFS salesman, had alreadywarned me that it would be a good idea to secure all the vacuum lines with plastic pull ties to prevent blowing one loose. Most of these 70+ vacuum connecions are located under the intake plenum. Hey Paul....what you doin' this weekend? Removing the throttle body and plenum revealed all of the connections. A six packlater (about 5 hrs) and 80+ pull ties lighter, the job was completed but the hiss remained. Eventually we(Paul) found the problem....the stock rubber hose running off of the turboshad a small split at the clamp. Replacing it with a PFS pressure clamp and hose finally fixed the problem.
Suspecting that the car was running rich, I subsequently purchased the handheld controller which allows for programming changes of boost, fuel, and timing. AlthoughI found the documentation was not totally clear (particularly with vent and boostadjustments), Peter Farrell was able to talk me through most of it. I made boost and fuel adjustments to tune the car. Once I knew what I was looking for, this procedurewas fairly straight forward. Subsequently, I purchased the data acquisition software which allows for analysis of collected run data and fine tuning. This addition allowedme to view data on the PC at home to make proper adjustments to the boost, fuel, timingdata tables. I used an HP200LX Palmtop (about $400) to run the collection software inthe car and then downloaded the collected data to my home PC for analysis. My only criticism of the software is that it is difficult to get graphical data or easily export the data to spreadsheet software that will.
In conclusion, I am very happy with the way everything worked out. Support from John and Peter at PFS has been excellent. After all the bugs were worked out and thecar was tuned, the results are very impressive. The car is producing 360+ HP & is capable of reaching 60 MPH in less then 4 Seconds & 100 mph in 8 Seconds. These results are with upgraded tires. About Dr-Felix Wankel