Toyspeed.org.nz Message Board

by **Bazda** » Mon May 03, 2010 2:00 pm

Find a new tuner.

You should be able to run 20-22psi on a stock 4agze 8.9:1 engine with 98 pump gas.

by **gasman** » Mon May 03, 2010 2:25 pm

i got 8.9 gze pistons with a 0.8mm headgasket and have pushed it to 21psi on 98. you will be fine.

by **mr30%jr** » Mon May 03, 2010 2:42 pm

yea well hence my assumption of GE pistons... sure dont need need to pull it down at all...

OMG so shiny! · by **Dell'Orto** » Mon May 03, 2010 7:13 pm

Yeah just wind it up til it pings, then back it off a couple of psi

by **matt dunn** » Mon May 03, 2010 7:48 pm

I run those same pistons in my car even though it' 1800cc,
and it's still around that 9:1 comp ration and I run 20psi and 450hp,

so the pistons will be fine.

by **MAGN1T** » Mon May 03, 2010 11:56 pm

evil_si wrote:compression test doesnt tell you the compression ratio

It gives you a fairly good idea.

If your compression numbers are 150 ish then CR is likely to be close to 8 to 1.
Likewise if compression is 200 then then CR is more likely to be closer to 10 to 1.
Of course valve timing affects it too but at 200psi I'd suspect your CR is a bit on the high side.
2 headgaskets is a pretty good way of dropping CR, it's not like it's never been done.
You could always play with the camgears?
What compression numbers are they supposed to make?

Steve

by **4agtepwr** » Tue May 04, 2010 12:04 am

Website · by **Bling** » Tue May 04, 2010 12:06 am

Dell'Orto wrote:Yeah just wind it up til it goes F**KEN BANG, then back it off a couple of psi

*cough*

by **4agtepwr** » Tue May 04, 2010 12:53 am

Leave it as it is, Two head gaskets is a bad idea, it deletes squish which promotes det by letting end gasses ignite causing an uncontrolled burn in the chamber, this will not help you in the quest for power and is just something else to fail, a head gasket is not designed to seal against another headgasket! Its designed to seal against machined flat surfaces. As Bazz and others have said 8.91 pistons will be fine well past 20 psi and 200 psi indicates good ring seal, I wouldn't touch it.

by **Quirky** » Tue May 04, 2010 12:58 am

I have a completely standard GZE and run 18 psi.
Been 6 months, and no problem so far.
Its not like you floor the car constanly anyway, it only sees full psi seconds at a time.

by **rollaholic** » Tue May 04, 2010 8:28 am

MAGN1T wrote:2 headgaskets

im sure its been done before, i just find that particularly funny coming from you.

by **thegreatestben** » Tue May 04, 2010 8:48 am

Stock toyota gze pistons handle the boost jandle in my 7A just fine.
two headgaskets is the kind of thing you do to a K series :lol:

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