well, going from stock compression to 10.5 then to 8.8 ,man i turned the boost to 10 psi and drove it a little. did a little tuning and got everything pretty good, running a little rich ~.96-.97 but man it just don't feel as fast as before. what PSI would produce equivalent HP on 8.8 comp compared to 10.5 comp. because 10 psi on 8.8 is really not the same as 10 psi on 10.5. I liked the 10.5 with 10 psi of boost alot better, I could break the tires loose in 1st-3rd gear, but now i can barely break them loose in 1st and 2nd at 10 psi.
am i doing something wrong, or is this the way it is with low comp pistons?
thanks
James

Yea, 10psi and 8.8:1 isn't very impressive to drive. It's impressive when you go from nothing to that but once you've seen real power everything else sucks! 10psi and 10.5:1 must have felt like 20psi on 8.6:1 or something in that range.

I was running low 15's at my altitude (~5800ft) on 5psi and 9.6:1 compression. After the rebuild I went to the track and was boosting 8psi w/ 8.6:1 and was running the same numbers. But running more boost is why you lower the compression anyway.

My guesstimate would be you need to run 15+spi to get the same feeling as your 10psi and 10.5:1 compression.

Brian

thanks brian,
i'm gonna turn it up right after i change my oil
man i miss the high compression turbo feeling
i hope i can get it back when i increase boost.
lates
james

Yeah its like 4% increase for every point of compression

So if I just wanted to run 10psi, I would be better with the 10.5 compression?

turn it to 15 and I am sure you will like it.

I don't know if "better" is the right word. W/ higher compression you don't have to push as much air into the cylinders to make the same power as a car w/ lower compression. For example if I am running 8.6:1 pistons and boosting 25psi I would probably be in the 300-375 range (depending on the other mods to the engine) and if you had everything the same only w/ 10.5:1 pistons you would only need to boost to 10-15psi to be around in the same Hp range. The only down side is you need to make sure your tuned very well w/ the high compression because you already at 10.5:1 even before you put boost into the engine. You kinda have less room for error w/ higher compression pistons. I like the idea of higher compression and turbo. I kinda wish I still had the stock compression.

This was just a REAL quick and dirty explanation. Hope it answers your question.

Brian

i'm gonna turn that shit up tonight and see what happens
hehe
okay i got brave and i am now up to .9 kg/cm2
like 12 pounds at lunch time
it is begining to feel like tasty butta again
hehe
the thing that scares me is the sound that turbo makes when it spools to 12 psi. it really sounds scary!
lates
james

HAHAHAHA, The fist time you hear that thing at 15+ your like "OH MY GOD!" I love it...

When you line up w/ little punks they know their fucked when they hear that thing roar. Scary is absolutely the best way to describe it.

hey james, if your tuned well (on the rich side) you should be good for 15psi... dude i got to ride in your car with 15psi about when ic you..maybe i will rebuild sooner..hehe..im getting bored with only 9psi and all..



Michael 99gs
HRC Stage 2
http://www.dreamwater.net/purplebeast

>maybe i will rebuild
>sooner..hehe..im getting bored with only 9psi and all..

I got a spare '99 block if you want a loaner to build up. Kaiser has dibs on it, but it's just sitting in my garage for now. You can use the tools too if you don't have em, I ended up getting like $150 worth for this bish.

James :thumbsup AHHHH I CANT WAIT.... You going to the SD meet?

i'm thinking about the SD meet, is it on saturday? well, i found the cause of my lack of power. my clutch is only holding power up to 130 to the crank i turned up my boost controller and the turbo spools louder the rpm;s go up fast, but the car don't go any faster and my blitz power meter pegs at 117 WHP. SOOOOO my next question. Where is a good inexpensive place to get a modular clutch masters stage 4 clutch. i'm kinda getting from the people on this board that this is the clutch to get. like the ferrari of clutches for our car. Also how is the pedal pressure for this clutch, am i going to have to work out my left leg just to use it. also is this clutch streetable at all? does it have a nice hookup or is it just grab or no grab?
that's about it.
thanks for the info
James