As some of you know, a good friend shipped his CS to
TPC for the installation of its turbocharger kit and some other work. Considerable time and energy was spent by
TPC over several months to tweak the installation and the car was returned a few weeks ago. On paper, the results seem incredible: 423 RWHP (from 266 stock) and 359 ft-lb torque (from 230 stock). Using a 12% drivetrain loss factor yields about 480 HP at the crank (from 295 stock). Even more impressive is a torque curve from 4,000 to almost 7,000 rpm that stays more than 100 ft-lbs above the stock engine. Most impressive is all this happens with just 5.5 pounds of boost (less than 0.4 bar), meaning there's little added stress on the engine.
Add to that Milltek headers, a Quaife ABD, lightweight flywheel, front splitters, Porsche's rear aero spoiler, beefier adjustable sway bars, GT3 front and rear lower control arms; all finished off with a pro-racer's adjustments to the PSS9 suspension and what do you get? I took the car for a healthy test drive to find out.
First, the disclaimers. I'm not affiliated with
TPC and having spent no money for its work product, I don't even have a psychological reason to find its conversion worthwhile. Plus, having driven many turbocharged cars, having owned a few and having completed a lowered compression engine rebuild to turbocharge a 240Z in my garage, I think I've got more than an average understanding of what to look for - good and bad. Last, whether because I live in the "Show-Me State" or grew up in NYC, I'm cynical of vendor claims, especially from sellers of aftermarket performance goodies.
OK, I can't delay the conclusion. This is among the best (maybe THE best) high performance turbocharged cars I've ever driven. And I don't mean just aftermarket conversions, I mean including well integrated factory systems: 99xTT, Audi Rs, etc. I was blown away with the experience which far exceeded my "looks great on paper" expectations. This is a very well designed and executed modification with no negatives I could find, although, of course, component longevity, clutch life, etc. remains to be seen, as does its effect on one's driver's license.
In contrast to most factory turbos which run higher boost on lower compression engines,
TPC adds to the stock high compression CS engine. The result is that off boost the car is just as strong as a stock CS. But, hit the gas and there is virtually no turbo lag. Just an amazingly seamless, immediate, and very rapid ramp up of smoothly added thrust. No upsetting, violent or discomforting jolt like some cars I've driven. No dead or flat spots. Just a progressive addition from as low as 2,500 rpm, which at first feels linear and then geometric as you hit 4,000 rpm. It feels different than what the dyno would indicate because at about 4k the earth begins to shake, you get stuffed back into your seat and it feels like a big block V8 was dropped into the engine bay behind you. Automotive nirvana.
I can't say what the LWF adds to the system (other than the expected rattling at idle), but this thing spools up so quickly that hitting the rev limiter in 1st during hard acceleration seems unavoidable. Perhaps more practice would help, but you're out of 1st in a blink. I wouldn't be surprised if the fastest 0-100 time would be to spool up the turbo and start in 2nd.
In terms any CS owner will understand, when I floored the throttle while cruising in 5th at highway speeds the car accelerated faster than had I downshifted to 3rd in my CS. This is not a frightening car to drive, in fact it's joy is that it's so streetable, but it is frightenly fast. I was constantly focusing to stay below "lose your license" speeds. And that's maybe the only downside I found. The thrill arrives in bursts that can't last more than a few seconds on public roads. But that's the drawback of all high HP street cars. However, for those few seconds there's not much out there that'll stay with this
TPC CS. Indeed, my friend left a frustrated driver of a new C4S muttering to himself and no doubt planning to bring his car in for service after he was easily left in the dust despite his fruitless efforts to keep up.
I didn't hear any turbo whine, just the fluttering of the wastegate when I put my foot down. Mike
Levitas, to his credit, wasn't content to just stuff gobs of power into the 3.4. He obviously spent considerable time fine tuning the mini-muffler exhaust to produce a throaty, but not obnoxiously loud, resonance free sweet sound that reflects refined power. Very, very tasteful and well done.
Mike also didn't ignore the rest of the package. With the suspension changes and his expertise, the car is tight, solid and planted, with very neutral handling and easily handles all the power. As noted by Mike in the posted video, the stock brake pads are not up to the new performance envelope. That'll be changed tomorrow when we install the higher performance pads recommended by Mike.
I could go on, but suffice it to say this is one suberb modification. Easily the highest proven and most significant HP yield for the dollar. More important, the car has been transformed by giving it an engine to match its chassis and suspension, making it what many here have argued it should have been from the factory. Of paramount importance is that the design and execution of this project by
TPC is first rate and on a par with world class performance shops, maybe better. Take it from this cynic, it's perfection. Oh yeah, I want one.
I won't have an opportunity to drive it on the track until Aug 6th. A track report will follow thereafter.
I didn't expect to be as blown away (pun intended) as I was. I even waited a week before posting so my euphoria would wear off. It didn't. 
