piston help Options

[trd94]

ok i have read that the 4age head gasket fits a 7afe so i would like to know if i use a set of 4agze pistons with a 2mm head gasket will i be ok for 10-12psi of boost or will the gze pistons raise the compression to much even with the 2mm steel gasket just need some input befor i buy parts i dont need thanks guys

[playr158]

you arn't a newbie

stickie
http://www.6gc.net/forums/index.php?showtopic=28068

you probably are just better of getting new OEM spec pistons from TOPLINE
http://www.importperformanceparts.net/impo...istons-toy.html
then using the 4agze headgasket

[trd94]

yeah i searched and read what you wrote about the pistons an i got a little confused ,you never said how thick of a gasket to use to get your compression back down so i thought i would ask

[playr158]

2mm is the max you really want to go...
the best solution is arais or wiseco custom pistons designed to lower the CR and OEM thickness...

but with proper tuning you could run a 10.XX:1 compression ratio with less boost to make the same power u would using a 8.5 or 9:1 compression ration

[trd94]

this is true ,and if i would use the 10:XX:1 ratio would i not gain a little more torque down low and a little fatter power band?

[playr158]

with the higher compression ratio, you would gain better off boost driveability. so yes down low you would get some help

[lagos]

raising compression and adding boost is a bad idea.

[playr158]

how is runing a low 10.x:1 or high 9.X:1 compression a bad idea?
many motors run high compression boosted noproblem.
hondas par example into the 11s and boosting in the teens and near 20psi completely fine
the 7th gen celica 11.5?cr and boosted fine

like i said if you can have proper tuning (which with a knowledgable tuner and a greddy ultimate) could probably be done.

some reading from MR2oc
Higher compression builds

This post has been edited by playr158: Feb 12, 2007 - 11:11 PM

[trd94]

raising compression and adding boost is a bad idea.

that is not so true any more , it just depends on how much boost you add, i want to get around 225hp out of my 7a ,so i could use about 15psi on a lower compression ratio, or if i run a higher compression ratio i would only have to run lets say 10 psi , and i could get my hp sooner, and as long as i use a strong head gasket and a good tune with my greddy unit i should be good, but correct me if i am wrong ,

This post has been edited by trd94: Feb 12, 2007 - 11:15 PM

[playr158]

well not just the headgasket
you would be able to use a thinner then 2mm headgasket (less chance of blowing)
but you would also need a higher octane gas (93octane)
and the correct ignition timing/fuel tuning (ems)

[trd94]

well not just the headgasket
you would be able to use a thinner then 2mm headgasket (less chance of blowing)
but you would also need a higher octane gas (93octane)
and the correct ignition timing/fuel tuning (ems)

so than would a .5mm head gasket be better ,and i run 94 octane now as it is available around here, and i should be able to get the fuel and timing tuned with my emanage ,right

This post has been edited by trd94: Feb 12, 2007 - 11:26 PM

[lagos]

hondas par example into the 11s and boosting in the teens and near 20psi completely fine
the 7th gen celica 11.5?cr and boosted fine

you cant compare 11s hondas to his car. you are talking about cars that run nothing but race gas, and have better tuning then just a piggy back. as nice as the emanage is, its still FAR from a standalone.

as far as 7th gens go, their community has had a very hard time coming up with a reliable turbo kit for the GT-S or even the GT. most of their guys have to fully rebuild the motor to run any kind of boost.

trd94, the higher the compression, the harder of a time you'll have trying to combat knock on pump gas. even just 10psi, is still a fair bit of boost and can cause a good bit of detonation.

why are you even thinking about opening up the motor? did something go wrong?

[trd94]

hondas par example into the 11s and boosting in the teens and near 20psi completely fine
the 7th gen celica 11.5?cr and boosted fine

you cant compare 11s hondas to his car. you are talking about cars that run nothing but race gas, and have better tuning then just a piggy back. as nice as the emanage is, its still FAR from a standalone.

as far as 7th gens go, their community has had a very hard time coming up with a reliable turbo kit for the GT-S or even the GT. most of their guys have to fully rebuild the motor to run any kind of boost.

trd94, the higher the compression, the harder of a time you'll have trying to combat knock on pump gas. even just 10psi, is still a fair bit of boost and can cause a good bit of detonation.

why are you even thinking about opening up the motor? did something go wrong?

no nothing wrong ,she is running like a beast , but i just am thinking of pushing it a little more , my goal was 225-250hp every day , i just dont know if the stock bottom end is going to take ,and i have around 97,000 miles on her and it is time to change the timing belt ,i change it every 50-60,000 miles ,so i thought when i do this i would upgrade some that is all

[playr158]

lagos you do realize stock compression is like 9.5 on a 7afe i think
or its in the 9s...all that is required stock is 83 octane...
an Emanage with 94 octane @ a 10:1 CR should be obtainable with minor implications.
and actually those hondaz are on pump gas
**** add some H2o injection for knock control

@ .9bar doggy was making 206whp on an unopened motor
increasing the CR and tuned @ the same .9 bar it could probably see in the 220s
and some water injection maybe 230s

do we really know? no
is a higher then stock compression build possible? yes
will it take research and some trial & error? yes
does this mean we shouldn't try? no

I'll even donate the motor for 40$ to do it with

This post has been edited by playr158: Feb 12, 2007 - 11:53 PM

[trd94]

lagos you do realize stock compression is like 9.5 on a 7afe i think
or its in the 9s...all that is required stock is 83 octane...
an Emanage with 94 octane @ a 10:1 CR should be obtainable with minor implications.
and actually those hondaz are on pump gas
**** add some H2o injection for knock control

I'll even donate the motor for 40$ to do it with

ok well i got the $40 and i think it is possible does any one know what the pistons part # is and i do want the 4agze right , and i do have water injection to help with knock thanks lagos for the smurf piss idea and what mm should the head gasket be? yeah i dynoed mine at 12 psi and i hit 207hp on the stock insides ,also i am running a intercooler sprayer also like you suggested .

This post has been edited by trd94: Feb 12, 2007 - 11:56 PM

[lagos]

can you post your dyno sheets? that way, we would probably have a better idea of where to go next.

i just think you are looking at this all wrong. your motor already has a pretty high compression. your real bottle neck is probably in your head, turbo, or tuning. i just don't think you'll see the results you are looking for by swapping out your pistons.

[playr158]

probably in the head?
lol i think thats an understatement
the head IS the weakest link on the 7afe

[lagos]

probably in the head?
lol i think thats an understatement
the head IS the weakest link on the 7afe

so, why are you recommending bottom end work?

the weakest link in the 7afe or any NA motor is the stock ecu.

[playr158]

because 7afe pistons are right about even with the head..you're more likely to fry pistons and rings on a boosted 7afe then you are to fry a head?
its preventive maintenance + upgrading
put if you're going to be in there anyways you might as well spend the extra few on some headwork...which won't really gain you anything
the 7afe is a DOHC motor controlled by a single cam..that sux for adjustment. the cams themselves are of conservative nature
and on a nearly 100k mile motor i'd be more interested in pistons before i would the head (besides valveseals which i would do as well)

if you feel so inclined and have a little time, grab a book or research porting and polish online...you can do it at home with a dremel tool for a small cost which is strictly materials ie dremel attachments
all roads lead to rome it just depends which way you want to get there and how much you are willing to invest..

also to quote oobe
"7afe pistons are like powder"

This post has been edited by playr158: Feb 13, 2007 - 12:59 AM

[lagos]

because 7afe pistons are right about even with the head..you're more likely to fry pistons and rings on a boosted 7afe then you are to fry a head?

but when you raise the compression, your going to be more likely to get detonation that would in turn kill your ring, pistons, head gasket. the preventive maintenance could end up causing more problems.

you probably stand to gain more power by ditching the crude safc tune, and spending some of that money on a better ecu. then, if/when something breaks, go in there and upgrade it .