raspberryroadster

thks that is good info and have stored that. but....still think i would wait for rebuild time and would do internals - personal opinion - heat management is better dealt with up front with forged internals/lowcompression set up rather than suffer slings & arrows of extreme engine failure at WOT.
low boost (say 5p.s.i. )by forced induction formula will add about 80hp at the crank to a 964 engine and still create heat issues to be dealt with (in my cobra's case i am tuned to run 15p.s.i. but need 94 or better octane which i know cannot be sourced outside of this province - in many areas - thereby requiring addition of octane enhance - pricey solution).

if you are going to forced induction (whether sc or turbo....they both generate same hp increase when installed at equivalent levels of boost) might as well do a properly prepared engine and go to mid/higher level of boost on a safer basis than than low/moderate level on an engine with stock internals.

cobalt

Do consider my 94 turbo is producing 450BHP at 1 bar of boost with basically the same motor nearly identical internals is single plugged and running only slightly lower compression using old school CIS. The motor is in no risk so long as AFR's are controlled and monitored. Considering the 964 3.6 motor is twin plugged with motronic controls you should be fine. I agree if you start cranking up the boost it would be time for some internals but now your talking $$ and it might be cheaper to drop a 993TT motor in its place.

I also feel you should obtain more than 80 bhp gain. If I can gain 40 bhp out of a stock motor with little more than a muffler and chip i would assume a turbo and proper tuning would produce more. I know the local protomotive guys do an outstanding job and produced some powerful cars with these kits. With very few issues.

raspberryroadster

yes and?
....your engine's forced induction running at almost 15p.s.i., thereby (by formula- which i agree is not perfect) results in approaching 100% gain in hp over equivalent stock-naturally aspirated engine (forced induction-boost formula is of course incremental/not linear).
you do not have to reduce overallcompression much to assist in pre-ignition/heat management....but it is necessary (& with highest level of octane obtainable to prevent pre ingition).
if you enhance a naturally aspirated engine (with exhaust/chip etc) then add forced induction the factor of power increase is based on enhanced engine - making it doubly dangerous on throwing a rod-burning a piston/valve), custom tune may assist.....but i have seen results of failed engine at WOT and (and remember every time you engage forced induction go WOT you shorten lifespan of the engine - that's just a fact, heat generation just does that) - so guess all i'm saying (having been there done that) - would do the internals in a 964 before considering forced induction, then likely do the levels of boost your fine car is running at.

cobalt

I think your missing my point the 964 turbo 3.6 was designed to run at just about .9 bar from the factory, safety cut outs engage at 1.1 bar anything over that is a concern. The engine is basically the same as the N/A with slightly lower compression and does not have the twin plug. The turbo engines easily produce upwards of 400 rwhp using an antiquated fuel injection system. Anything above that and the FI falls short. There are factory turbos with 1 bar springs and have 90k plus miles on them without issues, these engine can handle it assuming AFR's are within spec. What makes you think that they can't handle this power or boost level? I know of more N/A cars with detonated engines from pushing them too hard in the turns with too little fuel in the tank than failure due to a few extra PSI. The factory raced these cars with nearly .95 boost and no improved internals other than cams and won many races.

Why would I want to consider doing expensive internals on a street car that lives far less than 50% of its life at WOT? I can see your point for a track car but for the street you are well within the prescribed limits of its design. There is nothing extraordinary about the factory turbo regarding heat dissipation over the N/A cars. If anything the N/A cars have an advanced cooling fan. Porsche if anything over engineered these cars and I would not hesitate to say I know of many stock boosted engines that have had long lives and no issues. I do know of a few that had issues but more often than not it was more related to over revving or bad gas.

springer3

Selling it and buying a factory turbo might save some cash. If you consider re-sale value, upgrade to a factory turbo is a no-brainer.

I am at go-directly-to-jail speed in less than 10 seconds. A turbo gets you to stay-in-jail speed in the same amount of time. Therefore I am happy with power where it is now (cup pipe and weight reduction has me about the same performance as 20 HP above stock).

-nick

I agree with the OP's sentiments. Needs more power!

The TPC kit is looming in my future. My take is this:

1. I've done a wild turbo upgrade before, and while you can ultimately make more power more easily, I really don't feel like swapping pistons in this engine. Which seems to be a requirement for the turbo kits that are out there. I'm thinking that an extra 100hp will suit me for a while.

2. I actually like that TPS offers an liquid intercooler. I like the stock retractable wing and I feel like the turbo wing (required for a turbo air-air IC) is a bit too flashy for my tastes.

3. The TPC kit is actually bolt-on. I've read the instructions. It's a relatively simple operation. I would take it directly to a dyno to make sure that the air:fuel is healthy before exercising it. I want to keep the stock (quiet) exhaust and airbox. I want to make sure that it will be tuned for that.

4. As Cobalt has written, the engine can take the power bump. Keeping a healthy air:fuel is key.

And for those who've done it (Ilko?) can you tell me how removing the rear electric fan alters the climate control? And also how the stock clutch handles the extra take-off torque? I sent TPC a note, but haven't heard back.

Nine11

Yeah, it's not going to be blindingly quick per today's supercar standards. But the car would be a great one at that price point. I see you have a TDF Blue one, my favorite colour.

964speed

Mine too! I drove a 430 last week...simply blazing...super fast...But I'm a "Porsche Guy" in my heart...

wellcraft290

I have heard mixed things on the TPC kit with actual horsepower results.

964speed

Me too...can't get a straight answer from them

ilko

Funny, everybody's "heard" something but nobody's actually driven one

The TPC kit comes with a heater bypass tube, like the one on RS cars. The climate control unit itself is not affected although you do get less heat. Or rather, heat doesn't build up as fast. Most people with RS heat bypasses don't complain, but at the end of the day it's a personal choice.

I have an RS clutch, LWF, and a GT3 pressure plate so I can't comment on the stock clutch. However, the power delivery is very linear, there is no sudden rush. It won't blow your mind away, but it's a nice increase over stock. I used to own a 964 C4 and it was a dog in comparison to my RSA in the acceleration department. YMMV.

wellcraft290

does anyone actually know what the increase of power is by the kit? I know they claim up to with teh intercooler.

Nine11

That's me....Porsche since I was a trike kid. But the Ferrari's and Lambo's are certainly eye catching and alluring. Not sure I want to head into that path though. There are times I want something newer and faster, but the watercooled P-cars do nothing for me....so I look at the Gallardo's and F cars. But a quick rip in the air cooled classic has me smiling again. I've also looked at the V8 Esprit TT....always loved the Esprit. Or do I beef up the 964.....

ilko

~60HP for the non-intercooled version @ a very conservative 5 PSI (0.35 BAR).

Nine11

At the wheels?