Last Update: September 3, 2007
Years ago, I bought this nice 35th aniversary mustang convertible from the factory. It has served me well as a stock pony while serving out it's 3 year warranty sentance. However, that time has passed. I plan to use this site to catalog and document my changes to the car to get both more power out of the small block 3.8L V6, and to otherwise just play under the hood for the sake of playing under the hood.
In the interest of good history, here's a look under the stock hood on it's third birthday. Many of the changes I plan are one way, so this is the last you'll ever see of this arrangement.
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Officially the car came from the factory with a 3.8L (232 cubic inch) V6 Ford modular block engine. According to the factory specs, this power plant delivers 190 HP@5250 RPM and 220 ft-lb torque@2750 RPM. These are of course the flywheel numbers. Actual performance will vary 2-3 HP depending on the individual car and weather conditions. I didn't dyno my particular version stock.
190 HP is nothing to scoff at, however Mustangs are heavy cars. The stock v6 coupe tips the scales at 3124 lbs. My convertible adds 140 lbs to make up for the lack of a structural roof. Add me in the driver seat and another 100 lbs of gasoline and you end up pushing 3550 lbs or so down the track. The result is a car which will comfortably run up to 115-120 mph, but doesn't get there in as much of a hurry as one expects from a Mustang.
So, it looks good, sounds good, but needs what all Mustangs need. MORE POWER. This brings us to the first modification.
Episode I - The Supercharger |
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So, the supercharger is in, but is it doing it's job? I personally won't feel comfortable until I can see the real boost pressure numbers and make sure the computer is keeping tabs on the mixture like it should. That requires new instrumentation and thus we have episode II.
Episode II - Fuel/Air and Boost Gauges for the Dash |
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Now, all of this theoretical power increase is well and good, but you never
know what you've got unless you test it. So, I paid a visit to the guys at
Borchardt Speed Automotive and their Dynojet chassis dyno. Since I didn't
run a baseline on the car before putting in the supercharger, all I have for
a stock comparison is the flywheel curve published by Ford for the 1999 3.8L
V6 (left). The results of the test?
Rear wheel horse power at 5250 RPM is now a SAE corrected 216 HP and torque reads almost the same peaking at 215 on the red line. Unfortunately this test was premature, since the first chip from Vortech didn't sit well with the engine and the whole system was running dangerously rich. |
Because the initial numbers seemed a little low to me (and the computer was screaming RICH MIXTURE at every opportunity), I decided to have a conversation with the folks at Vortech. After a little diagnosis which I cover in painful detail in episode I Vortech decided the program in the chip required adjustment. With the new chip come new dyno plots. The curve below was generated with the G-Tech Pro/Competition that has been shown to be very accurate when compared to the DynoJet numbers. The final numbers for the Vortech install are therefore 230 rear wheel horsepower and 223 ft-lbs of rear wheel torque.
After all this time reading and skimming the auto parts catalogs, a little cosmetic touchup was probably inevitable. So the next change, while small, is all about show and has nothing to do with go.
Episode III - Just a little more shiney |
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In between performance modifications I've bought a few toys. Some out of necessity (like the ODB-II scanner) and some just because they looked way too cool to pass up. The G-Tech Pro/Competition falls in the latter category.
G-Tech Pro/CompetitionA street dyno for the masses |
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In preparation for continued changes to the car and even higher fuel demand, a new fuel pump is in order. I think the stock pump is a 130 L/hr pump, but the new one is MUCH bigger and should keep me from running lean and making a huge mess of the engine.
Episode IV - 300 L/hr Fuel Pump |
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Now that we're ready for higher fuel delivery, it's time to see if we can refine the chip programming. With the addition of a new MAF sensor some of the quirks of the Vortech kit... like the MAF signal conditioner ...get resolved and we finally take full advantage of the 93 octane gas.
Episode V - Fordchip and Lightning MAF |
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Having got a lot out of the Fordchip and MAF, I finally got around to putting twin pipes on the car. Installation of the GT exhaust system is detailed in Episode VI
Episode VI - Dual Exhaust |
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The final dynos and current status of the car's performance are finally clear as day. New software from the folks at G-Tech has substantially cleared the air over what represents a real vs false peak. The plot below shows current performance and the factory profiles side by side. Peaks are 213 SAE RWHP and 221 SAE RWTQ
