which compression rato ? wiseco pistons

[rforres]

short version of my car
90 talon awd
pte 56 trim turbo, engine in machine shop now, i will have supporting mods when it all comestogether.
gm maft
dejon race fmic
maf in uicp
cold air pipe in fender well
arp fasteners
cometic head gasket
3" atr o2 elim turbo back
pte 780 injectors
zex wet kit
auto alchemy fuel system
supra pump rewired


my question only pertains to compression ratio, the cometic head gasket is .054 thick, pretty thick for a gasket, ive read that it will drop ur c/r by .3, should i go w/the 9.0 wiseco's that will be 8.7 w/the thick gasket to help spool the 56 trim or should i go w/the 8.2 wiseco piston that will be 7.9 after the thick head gasket , just the pros and cons of too much compression ration vs too little , is the higher level going to cause more knock and detonation ? harder to tune ? will 7.9 be enough ?

thx in advance.

ronnie

 

[91 NT Eclipse]

9.0 will give you better off-boost throttle response but 8.2 will allow you to run more boost.

 

[rforres]

off boost ? is there such a thing, i forgot to mention it will not be a daily driver, used mostly for drag/street racing .

 

[hose101772]

9.0/1

 

[gritsak]

yeah def. go with the 9:1 IMO

 

[DSMJim]

and dont run that gasket either. Just go 9:1. The pistons are strong enough to have higher compression and lots of boost. You should be able to run 26+psi of boost with those pistons and a set of rods. Lower compression will save the pistons if they are weaker but with strong enough material (like Weisco uses) you can have high compression and lots of boost together as one big happy family. Have your cake and eat it too...

 

[98Turbbo420A]

Originally posted by DSMJim
and dont run that gasket either.

whats wrong with thr cometic head gasket ?

 

[Vegas Smith]

"and dont run that gasket either"

I hate it when people make vague comments then jet, never to be found again. Why shouldnt he? If slowboy reccomends it then it must be pretty good.

 

[swordfish]

Blah.. The cometic gaskets are fine. They work great.

jeff

 

[RACER-X]

if jeff said there gaskets are good and slowboy says there good... i would say thats good enough for me. oh, and like stated above... with the wiseco pistons in 9.0:1 should be fine.

 

[rforres]

so again, 9.0 wiseco's -.3 for the .054 head gasket = 8.7 static compression, am i going to have any problems running 25-28 psi on pump gas, it will mostly have 116 in it at the track and 100 sunoco if i know im going out on the street to play around but if im just driving it to work for fun 1 day it will have 93 octane in it . so what do u think as far as boost psi on 93 octane.
someone get a wiseman to look at this thread.

i read a lot of threads about the new pte turbos, most think that the 56 trim will be a good pump gas turbo, someone even dubbed it the "50 trim killer" so its important to get the best answer as the engine is in the machine shop, as soon as they tell me the overbore i will order pistons, just which ones to get ?

 

[nowayout]

My stock motor was living with 18 psi of boost on a 60-1s trim on 93 oct fine.
i have 780 too and that seems to be close to the limit on 93 oct. Do to injector pulse being at 75%.

At 20 psi it's close to 80% injector pulse then my car starts to lose timing.
With 100 octane I can see 25 psi of boost but I don't have it at the pump around here. So I've never tried it.

With my motor being built right now. I can see running a lot more boost at 25-28 with enought Fuel and good timing.W hen I'm talking about tiiming it's on a stock ECU.

I'm putting in 9.1 weisco piston too with eagle rods.