pistons on stock ecu

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pistons on stock ecu

Postby aus jd 2703 » Wed Jul 29, 2009 1:23 pm

ok i am thinking bout running my stock ecu with some cp 9:1 forged pistons and a fmic, is this possible or will the ecu's mapping be to far out for te new compression ratio?
if it matters its an Australian delivered gt four ecu (non rc)
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Postby Gary ST165 » Wed Jul 29, 2009 2:48 pm

i think it will run OK :) >>> well put it this way... i'm running approx 9.0:1 CR on stock 185 RC pistons and RC ECU, due to fitting a 1.0mm MHG and having the cylinder head skimmed 0.08mm.

FYI, if the ecu detects knock it will revert to a safer look up table.


how long do you plan to run the stock ecu?
>>> because it will continue to bore wash
...and you will never make the most of the forged pistons...ie generate the heat required @ 350 > 400 bhp to take in to account the extra clearances for the high expansion pistons. piston slap + over fuelling will result in a very short engine lifespan.
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Postby vip09 » Wed Jul 29, 2009 5:23 pm

It will work perfectly find. I ran 9.0:1 pistons with a TD06-20G turbo on stock ecu and fuel sytem. It ran GOOD! :)
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Postby klue » Wed Jul 29, 2009 5:47 pm

ecu doesnt care what piston you have.
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Postby gt4tified » Wed Jul 29, 2009 6:55 pm

klue wrote:ecu doesnt care what piston you have.


Precisely.
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Postby aus jd 2703 » Sun Aug 09, 2009 10:41 am

trying to use my own threads,
has any one had good or bad luck with brands of pistons?
im looking for 20 though over 9:1cr
so my main options are:
ross
arias
CP
i hear good things bout cp but nothing about the other?
opinions please?
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Postby ___Scott___ » Sun Aug 09, 2009 12:46 pm

I hear good things about BRC Performance pistons from good engine builders:
http://www.brcperformance.com/importpistons.htm

Also consider "Roller-Wave" pistons from Energy Dynamics. They don't list pistons for the 3S-GTE on their website, but they do have them:
http://theoldone.com/components/pistons/index.html
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Re: pistons on stock ecu

Postby BriinumsBo » Tue May 25, 2010 1:12 pm

anybody got old 86.5mm pistons for sale? oem or forged, doesnt matter, dont want to buy fresh as probably someone has them lying around..
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Re: pistons on stock ecu

Postby klue » Tue May 25, 2010 2:18 pm

buying a used piston lol
do you reuse your condoms too?
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Re: pistons on stock ecu

Postby BriinumsBo » Tue May 25, 2010 2:26 pm

klue wrote:buying a used piston lol
do you reuse your condoms too?


:rofl:

whats wrong with buying used pistons and changing rings?
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Re: pistons on stock ecu

Postby Mafix » Tue May 25, 2010 3:55 pm

from mr2oc.com rsrace
Ok so Ive gotten several questions and concerns about pistons and compression ratios with the 3sgte pistons on the market and I wanted to make a post to clarify everything.

CP, JE, and SRP all have 9.0:1 pistons. Its the only compression ratio they offer, and I often get customers who just prefer 8.5:1.

Arias and Ross both list a 8.5:1 piston but heres the part to pay attention to.

CP/JE/SRP all list their compression ratios assuming an aftermarket .040" (1mm) thickness headgasket.

Ross/Arias both list their compression ratios assuming a factory .056" (1.4224mm) thick headgasket.

Well, if you measure the compression ratio with the CP/JE/SRP pistons using a factory headgasket thickness like Ross/Arias do, you get an 8.5:1 piston, and likewise, if you measure the compression ratio with a Ross/Arias piston using a 1mm aftermarket headgasket thickness, you get a 9.0:1 piston.

So, all of these pistons are the same compression ratio, just listed in different ways. I got with my guy at JE and we used their high tech fancy shmancy inhouse software to get the compression ratios using different thickness headgaskets and this is what we came up with...

Here are the headgaskets we worked with that are available for the 3sgte:

TRD: 0.8mm
Cometic: 1mm
HKS: 1mm & 1.6mm
Apexi: 1.1mm & 1.5mm & 1.8mm & 2.1mm

(CP/JE/SRP/Ross/Arias Pistons)+(TRD 0.8mm Headgasket)=(9.2:1)
(CP/JE/SRP/Ross/Arias Pistons)+(Cometic/HKS 1mm Headgasket)=(9.0:1)
(CP/JE/SRP/Ross/Arias Pistons)+(Apexi 1.1mm Headgasket)=(8.8:1)
(CP/JE/SRP/Ross/Arias Pistons)+(Factory 1.4224mm or Apexi 1.5mm or HKS 1.6mm Headgasket)=(~8.5:1)
(CP/JE/SRP/Ross/Arias Pistons)+(Apexi 1.8mm Headgasket)=(8.375:1)
(CP/JE/SRP/Ross/Arias Pistons)+(Apexi 2.1mm Headgasket)=(8.1:1)


Wiseco's 9.0:1 piston however is 9.0:1 with a factory .056" (1.4224mm) headgasket, so it truely is a 9.0:1 at the same headgasket thickness where the rest of them are 8.5:1

If you want to get close to an 8.5:1 compression ratio with a Wiseco Piston you will need to use the Apexi 1.8mm Headgasket. That combo will put you right around 8.6:1 compression. or you can use the Apexi 2.1mm headgasket to get to 8.4:1 ... more clearly illustrated below:

(Wiseco Pistons)+(TRD .8mm Headgasket)=(9.4:1)
(Wiseco Pistons)+(Cometic/HKS 1mm Headgasket)=(9.2:1)
(Wiseco Pistons)+(Apexi 1.1mm Headgasket)=(9.1:1)
(Wiseco Pistons)+(Factory 1.4224mm or Apexi 1.5mm or HKS 1.6mm Headgasket)=(~9.0:1)
note: i put the "~" because all of my calculations come up saying the wiseco piston is 8.8:1 with a factory headgasket thickness, but they advertise 9.0:1 so its about 9.0:1
(Wiseco Pistons)+(Apexi 1.8mm Headgasket)=(8.6:1)
(Wiseco Pistons)+(Apexi 2.1mm Headgasket)=(8.4:1)





disclaimer: this is slightly simplified, in order for it to be exact, you would have to do this for every bore size as well and go out a couple more decimal places on the compression ratio but for the purpose us car guys are using it for, this is as accurate as we need.
__________________________________________________ _______________
Now for the sake of saving time and making things easier for you guys, I will go ahead and list the part numbers for everything ive talked about in this post.

Cometic 1mm 87mm Headgasket: C4314-040
HKS 1mm 87.5mm Headgasket: 2301-RT034
HKS 1.6mm 87.5mm Headgasket: 2301-RT035
Apexi 1.1mm 88mm Headgasket: 814-T201
Apexi 1.5mm 88mm Headgasket: 814-T202
Apexi 1.8mm 88mm Headgasket: 814-T203
Apexi 2.1mm 88mm Headgasket: 814-T204

Wiseco Pistons:
K615M86 // 3sgte // Bore: 86.00mm (Standard Bore)
K615M865 // 3sgte // Bore: 86.50mm (+.020" Overbore)
K615M87 // 3sgte // Bore: 87.00mm (+.040" Overbore)

CP Pistons:
252061 // 3SGTE // Bore: 86.50mm (.020" 0.5mm overbore)
252062 // 3SGTE // Bore: 87.00mm (.040" 1.0mm overbore)

JE Pistons:
SC7449 // 3SGTE // Bore: 86.00mm (Standard Bore)
SC7450 // 3SGTE // Bore: 86.50mm (+.020" Overbore)
SC7453 // 3SGTE // Bore: 87.00mm (+.040" Overbore)

SRP Professional Pistons:
283458 // 3SGTE // Bore: 86.00mm (Standard Bore)
282309 // 3SGTE // Bore: 86.50mm (+.020" Overbore)

Arias Pistons:
3710101 // 3SGTE // Bore: 87.00mm (+1mm [+0.040"] Overbore)

Since this isnt a "for sale" post Im not going to post any prices that would clutter this up, but if you are interested in purchasing any of these items, or just wondering how much they cost, please check out our sale post in the vendor section here: http://www.mr2oc.com/showthread.php...065#post4017065

--------------------------------------------------------------------------------
Last edited by RSRACEcom : September 29th, 2009 at 08:13.
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Re: pistons on stock ecu

Postby BriinumsBo » Tue May 25, 2010 5:30 pm

thanks Mafix, I owe you a pack of beer! :D this should be written in alltrac.net tuning section, as it should cross everyone`s mind who wants to swap pistons and looks over the engine section on frontpage..

p.s. the link doesnt work..
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Re: pistons on stock ecu

Postby aus jd 2703 » Tue May 25, 2010 8:50 pm

Now I'm slightly worried about running my wiesco's lol they really are high compression. I'm aim ing for 9:1 with normal gasket thickness and a slightly decked head and block.
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Re: pistons on stock ecu

Postby Mafix » Wed May 26, 2010 11:52 am

just use a thicker gasket.
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Re: pistons on stock ecu

Postby Gary ST165 » Wed May 26, 2010 2:35 pm

BriinumsBo wrote:p.s. the link doesnt work..



It is a sticky in the 3sgte section on mr2oc.com

http://www.mr2oc.com/showthread.php?t=366753

hth
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