just wanted to jump in and say good luck, keep us posted with your decision.

i too, am very interested in going the higher compression stroker route.

i personally wouldn't go tt, and certainly not without an engine build.

if the engine build just wasn't satisfying enough on its own, i'd bolt on a supercharger. a pretty good article "Effect of compression ratio-supercharged 5.4L 4V." talks about the advantage of superchargers and high compression motors. yummy!

 

why will a 12:1 be pushing it with pump gas? (this is a question to expand my knowledge of NA motors, if you read it the wrong way.)

 

what the OP is likely alluding to is that higher compression engines are generally more susceptible to engine knock (additional fuel/air explosions to the "normal" ignition).

the octane rating is a measurement of fuel's autoignition resistance and autoignition is the lowest temperature of spontaneous ignition.

it follows then to resist knock (due to increased compression ratio) increase the fuel's autoignition point by using higher octane rated fuel.

obviously thats oversimplified, and many things can lead to knock and its reduction: reduce pressure/decrease compression ratio, reduce spark timing, increase engine cooling, remove carbon deposits, richen the fuel mixture, and many other things...

 

I remember reading a thread on my350z where someone had posted a 300whp NA 4 cylinder... and half the people were bashing it for being 'only' 300whp, and the other half were praising it because the VQ is pretty difficult to get too 300whp NA....

That being said, I have seen some stroker VQs, and the potential is definately there, especially if the same amount of work goes into the VQ as was put in the 4 cylinder...

Also, the 4 cylinder was running on race gas, not pump.

I'll post up the link when I find it.

*edit*

http://my350z.com/forum/showthread.p...ighlight=s2000

 

^i would have to say that the comments are always quite critical on that forum, as to why, I am not sure.

Thanks Nevdull for clearing up the compression and pump gas. I don't know extensively the mechanics and chemistry behind gas rating and knock, but I know when you are into the 12:1 compression and up, most are running race gas for added hp and safety for the motor.

In whatever case the budget for this project is probably somewhere around 15K at least. I will look more into it, I wonder why there aren't any shops just doing this to show case?

 

Ideal Gas Laws.

Higher pressure = higher temperature.

more compression = higher pressure = higher temperature = more likely to detonate/knock/ping.

Higher octane is more resistant to detonation/knocking/pinging.

 

After tripping over engine parts and getting myself full of oil while exploring the FI forum, I have been thinking the same thing. Perhaps the reliability of N/A trumps the overall of FI.

But a few questions come up. First, what power level can realistically be achieved? If the power vs. displacement curve is anywhere near linear, it looks like the strokers may top out below 300 WHP. Is 350 WHP a realistic hope?

Second, how will engine management work? Will the ECU from the 3.5 run the stroker? How would the engine be controlled and tuned?

 

I feel the same way you feel about being satified w/350hp from a NA. I'm getting a Sedan within a month and though boost is great, I figured I have a strong NA Sedan it would somewhat give me a chance to redirect monies to the style and exterior showmanship. Like I said I would love boost but when it comes down to the new Challenger coming out next year, what's Boost, lol?

 

agree 100%
350whp is faster then 90% of cars on the road.

 

Realistic figures are some where between 300 to 350. however 350 is not impossible just difficult and with the lack of examples out there of a stroked VQ on high compression, it's hard to say how attainable it is, it doesn't stop me from trying though.