Minor Threat

T'is true, I would take a look at people running Vitara pistons, I'm fairly sure the compression is really low (maybe not 7.5), so that should at least give you a good baseline to aim for.

DX trans/Lack of power Whichever you'd like to blame it on...

As for learning compressor maps, I direct you here: http://community.asiaosc.org/~zaliman/TurboSelector.htm

Just from plugging in some numbers, disregarding temperature and air density changes(which you SHOULD be calculating as well, don't worry it's all there) You look to be about at the limit of peak efficiency right around 15 psi, if you're flowing approx. 200cfm or 15 lbs/min of air.

That's also reading this map http://www.turbocalculator.com/compr...maps/t3-50.jpg T3, 50 trim which I think is what you're running, but I could be wrong, so make sure you've got the right map.

Brett

D16Y8-Z6

Lack of power maybe.
Some people said my last setup should of made 140-150 whp,
but it went 13.7 in a 4 door.
So ---- power lol.

Thanks for all the info.

B16CRXT

also, check this out for compressor map how to read info: http://www.honda-tech.com/zerothread?id=142398

projekteg

why the ---- such low comp. higher comp. with less boost is better than lower comp. with more boost. i'd rather run 9.5:1 comp. with 12 psi., then i would 7.5:1 with 15 psi :P

Minor Threat

I wouldn't. I like being able to run tons of boost without knock. Do you?

projekteg

no, psi is a ricer's unit of measurement. what good does it do to say "i'm running 15 psi", if a guy with higher comp. is running 10-12 psi. and making more power and spooling up much faster? lowering comp. takes away power, which in turn causes more lag, and we all know how much of a beast low comp. honduh's are before the turbo actually spools but if you just want to be able to say, "i'm running 15 or 20 psi", then yeah, low comp. is the way to go.

Minor Threat

I'm well aware PSI is an irrelevant measurement, but I also feel strongly towards the fact that compression has a much lesser effect than a lot of people think.

I won't lie, I've never compared the two, so I am talking out of my *** here, but from what I've read the window for knock becomes a lot smaller as you up the compression. Considering that most factory turbo cars run under 9:1 compression, and the fact that the majority of the people on this site are not supar tunarz, I'd say the bigger window you can get the better.

And ---- low spool. Design your manifold properly, run some water injection, and don't worry about power before the spool. It's not like FWD cars have traction from a dig anyways :P

Anyways, at the end of the day it's not about saying I can run more PSI than you, it's the fact that I can make more power than you because I can run more boost without knocking. So you know what? Props to D16Y8-Z6 for doing something different, and maybe opening some people's eyes.

projekteg

trust me, i'm well aware of tuning principles i personally see no need what so ever to go with 7.5:1 comp. ever, especially when there are 400+whp on PUMP GAS (which i shouldn't have to explain the difference of only using pump gas) with as high as 9.5:1 comp. without having to raise the octane level. and no, being able to run more boost with that low of comp. isn't necessarily going to net you more power, because like i already said, lowering comp. takes power away from teh motor, so that extra boost you're running is making up for lost power anyways. i do have personal experience tuning higher and lower comp. cars, and personally have run both. i have 9:1 comp. right now in my b16 and i wish i had went with 10:1 and lower boost.

B16CRXT

Thast why I stuck with stock internals on mine for now. If I blow this setup anytime soon, I plan to buy some stock forged replacements.

Tom-Guy

All other things being equal, a lower CR is going to allow you to make more power. Much more.

Look at the point you reach detonation as having reached a certain density with the compressed air/fuel. With a lower CR, you have significantly MORE combustion chamber volume and can fit significantly MORE compressed charge before you hit a dangerous/knock prone density...

... it's not that simple, because when you start making more power you also start making more heat, but there is still a significant general trend of lower compression being capable of more power and being more detonation resistant for a given power output.

Melted pistons are a problem with cylinder temps - broken ringlands a problem with combustion pressure spikes - broken rods due to being jackhammered on by detonation - etc.

YAAAARR!!