Porsche_Smile

i recently spoke to GMG and they told me they can do a 3.8L stroker kit....for about the same price that it would cost to supercharge the 3.4L ....... what is a stroker kit, how reliable is it and how well does it run....? it is worth doing vs a supercharger? anyone with experience pls chime in.... debating to supercharge or go this route.........

newport996

stroker kit is where they bore out(???) the block put in larger pistons, and rebuild the engine with a larger capacity...they will probably also do something intake and exhaust wise to match the engine...no clue on reliability....depends on how much material is in the block....i have heard in the past that if you go too big, the cylinder walls get thin and you can pot a piston through the block....but thats for extreme bores....maybe you should ask GMG what they do and how reliable is it...if they offer a warranty...how many they have done....etc....but a 3.4L to 3.8L increase isnt that big to jeopordize reliability...the next question is how much power will it produce? A supercharger will probably produce more high end power, but have less low end torque, so street driving in a 3.8L will probably be nicer, but if you live in the high rpm range a s/c may produce more power there...I would go with the 3.8L with all things being the same....less stuff to go wrong...less to deal with if anything does go wrong...like the muscle car guys used to say..."there is no replacement for displacement...."....Also a s/c costs about 10k....so can they do this for about 10k? That would be amazing....

ElTorrente

I would assume that since they call it a "stroker", that they would increase the stroke of the piston rather than just boring it. Perhaps they would increase the bore a bit also, but I'll bet much of the displacement increase is from the stroke.

newport996

ahh...yes...the stroke...lol

Russ Murphy

Stroker kit typically means increased swept volume without increasing the cylinder diameter which in turn means a different crank.

Tippy

If it is truly a stroker, you may lose a little upper RPM range due to the longer swinging of the crankshaft I would imagine but I dont know the specifics. Seems you may lose the characteristics of the motor a little.

The S/C would obviously make the most power all the way around but force feeding a 11.3 compression motor is scary with tons of cylinder pressure.

I think the best would be a resleeved block with big bores (up to the 3.8L) and leave the crank alone.

Porsche_Smile

hmmm... you guys are pretty knowledgable... GMG told me it would cost around the $10K mark, and it would pull a little harder then the 06 911 now......it's also because our cars, or the 99 are a little lighter, although since mine is a cab i think that negates the weight difference..... but sounds like a sound idea... i think i need to inquire more.......

Sids911

Are you going to use the additional power ? IMHO if you're on the street, you've already got a lot of "get-me-in-trouble" performance !

But then again, its your money and your car

I'm guessing a well designed 3.8L is better than overstressing a 3.4L engine by supercharging it. Don't forget to upgrade your brakes and suspension too !

Porsche_Smile

suspension is in the works now..... well see about brakes after....

turbochoo

One of the drawbacks of a stroker engine is the lost of rpm. Because of the longer throw of the crankshaft from the increased stroke it takes the engine a longer time to complete a revolution. There are two ways to increase displacement: one is by way of bore and two by way of stroke. Usually on larger displacement engines most engine builder usually bore and stroke the engine for increased displacement. In my opinion the joy of driving a Porsche is the ability to rev out the engine to redline and hear the engine sing. A stroker engine generally produces more torque and horsepower down low and not at the upper rpm bands. However after performing a quick search on Google for larger displacement 996 engine revealed most builder utilize only a larger bore for increased displacement so you might be in luck. All you have to worry about is the heavier piston from the increased diameter can affect rpm.

2fas4u

Super charge it dude! and you get at least 420 hp talk with vivid racing.

Mfletch

Getting stroked and blown sounds like a lot of fun!
I have had both stroked and supercharged engines in my vehicles (Saleen with a 331 stroker motor, 99 Range Rover with a supercharger)
Stroker motor.....very useable torque & horsepower gain plus you have a rebuilt engine. Easy to justify to the spouse when the engine needs rebuilt anyway.
Supercharger.....best bang for the buck, not recommended on high mileage engines without a rebuild.
Supercharged & stroked.....lots more horsepower and torque. You will be the only kid on your block with a supercharged & stroked 996.
Autofarm in the UK offers stroker motors up to 4.0 litres as does Motor Meister in Los Angeles. I have not seen any information on the performance gains from the stroker motors. The benefits of the three supercharger systems have been well publicized.
Either option sounds like fun.

Porsche_Smile

i highly suggest everyone here to get a stroker and a blown kit......

Paul 996

When I did research on this I found that the most cost effective upgrade for the 3.4L is to go to 3.7L, to get to 3.8/4.0 required swapping out to the crankshaft and bearing cradle to one from a 3.6L.

The 2002+ 3.6L engines have totally different cylinder heads and crankcases so they can go to 4.0L

In the end it was too spendy for me as a pure upgrade for my power but an option that I will certainly take should my 3.4L ever develop an out of warranty engine failure.

M Fig

Im a self confessed deal junkie. I always consider the deal when making a large purchase...and in my opinion, the supercharger is the better deal. I don't know how long you plan to keep your 996 but I assume you will eventually sell it. When it's time to sell, you can remove the supercharger and sell it on rennlist or ebay and get half what you paid for it (give or take a little). With the stroker, you will get nothing and I don't expect the car would sell for much if any more with the engine modded... So, in my opinion, if they both cost $10k, then the effective net cost of the supercharger is only $5K. Is the stroker worth double? I personally don't think so.

just my $.02