RallyJon

Why not just use a rising rate fuel pressure regulator and bump up the pressure a bit with boost? Might need a slightly higher capacity fuel pimp. It's dead simple, and the only drawback is slightly reduced injector reliability. Much less complexity than a 7th injector and controller and no more of a hack.

Quadcammer

yeah, thats a point. Im not sure what the duty cycle of the injectors looks like in stock form, but with only 6 lbs of boost, they shouldn't be taxed THAT bad.

993c2cab

Everyone it seems is skeptical about the tpc system - exept those who have them!! Any owners want to chime in who have had problems?? those of us on the fence are dying to find out if it will harm our cars. What problems have occured since the install?? Or is it just an all out fun fest!! Tell me please before I drop a bag of dough

Quadcammer

well, let me say that the additional injector works, and the system probably dumps enough fuel to get to a safe a/f, but I just don't believe that you can get the same precision and driveability as with a properly tuned car with larger injectors. However, it may be good enough for the average driver not to notice. Im a serious perfectionist though, so little things bother me.

MPB993

Guys,

as some of you already know I have changed my injectors to slightly larger but within the tolerances that the ecu could adjust for idle and cruise, bumped the boost, added a cold intake and an aquamist w/a injection system to my TPC'd car. Tuned it all using the innovate LC1 and splitsec 7th injector software to get the afr just right. I was getting 0.5 afr difference from left to right banks from using the 7th injector. The car is a tip but the performance numbers suggest otherwise. Only problem I've had is when the temperature goes above 25C hence the cold intake.

I have had it this way now for 60k miles, over 4 years and its been great fun.

I'm no perfectionist so it probably wouldn't appeal to everyone.

If I had the money again I would buy a TT but thats now and not 5 years ago

Just my opinion's of course.

Cheers, Mark.

mr_bock

Just my $0.02.... I wanted a nice looking install and extra power. The added driveabilty is a bonus. Loads of fun. Any problems? Not realy. Would I do it again? Absolutely!!!!

quasr

I held off purchasing the kit after speaking with the company. It seems the best way to go is to install the supercharger and intercooler together. Otherwise, it seems they described you would have to wait until the motor cooled off some between bursts or use of the supercharger. The company indicated without the intercooler, each boost would be less powerful due to heated air entering the unit. Decided that it is a complete package and at $10k installed, it would have to wait. Besides, not sure about anyone else but my 993 is pretty fast as it is. Just my $.02 worth. Thanks.

Quadcammer

Mark,
It seems like you are doing things in a better fashion than they come from tpc. Just curious, what size injectors did you end up using?

The only thing that worries me is that your banks are different by half of a point of a/f. Thats pretty significant in my mind.

MPB993

Quadcammer,

I think the 0.5afr difference is probably pushing the car out by a small amount maybe I am down by 1% on hp as a result so I run the average at around 12.8. But I keep an eye on knock as well which I never see on boost. The injectors I have used are ford motorsport red tops (233cc/min stock > 305cc/min). Its probably close to limits of what the ecu can control without a remap. This is not really best practice (LTFT near the limit) and I should really have it hot mapped. Idle and cruise are fine at 14.7 which I can adjust using the LC1 wide band that I use instead of the standard narrow band. The flat out fueling adjustment is still fine tuned by the 7th injector.

BR, Mark.

Quadcammer

wow, 12.8 under boost? You are a braver man than I. I have a lot of mustang Cobra supercharging experience, and its common practice in those circles to stay in the 11.3 to 11.8 range. Then again, If you are only running maybe 4 psi, it may not be necessary.

Have you pulled your plugs to check for little bits of aluminum?


Im glad to hear you run ford motorsport injectors. They are 30s I believe. If those fit without a problem, the sky is the limit. I run 60lb high impedance siemens deka injectors, which have the standard ford harness plug.

MPB993

Yep done all that nothing to be seen. But the a/w injection ahead of the supercharger keeps it all under control. That technology is so under rated. Lots of info on the turbobuick.com website which I have used to build confidence and lean out the afr to get the best results.

Land Jet

I have been warned by TPC to never hit the rev-limiter with the supercharger. The abrupt slowdown can break it due to the fact that it is belt driver as opposed to turbos which would continue spinning. For those who wish to contact TPC, here is an e-mail address. tchan@tpcracing.net

Quadcammer

Ah, I must have missed that you are running alky injection. It definitely works well, and since the meth is a high octane fuel, you get that added benefit as well.

Hitting the rev limiter with a blower is no big deal. The belt does not abruptly slow down, because the engine revolutions just stop increasing, they don't suddenly decrease. Think about it. If this were true, if you stabbed the clutch at 6,000 rpm, and the revs dropped to idle immediately, the thing would self destruct.

Stealth 993

Guys, I'm reading through this, & no one has once talked about putting in an adjustable fuel pressure regulator. This will up the fuel rate for the same duty cycle. Then you just get a WB O2, & about 1hr dyno time, to get the A/f proper.

96C4S

Flip your car and buy a TT you will be out the same amount and have a factory grade porsche with a good resale value.