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Discussion Starter #1
i understand that shot peened oem rods are good to 700 or so, but what are the stock pistons limits?

also, how much would coatings help and where to get em coated
 

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The Great Kruso
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400-450~ You could get them coated for better protection against detonation, but I believe this is the highest that the stockers have been taken upto.

Kruso
 
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Detonation will be your primary concern. Keep that down and they should be able to handle quite a bit of power.
 

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back in the day Lance Wolken did 550-580rwhp and pulled high 10's - low 11's at the track on stock bottom end.

SupraSpeed, did your piston rings eventually give up? Lance Wolken's rings gave up in piston #6 after a while.
 
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So is there stronger/upgraded rings that can be used with stock pistons?
 

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Silver88Turbo said:
So is there stronger/upgraded rings that can be used with stock pistons?
I'd like to know as well, since im replacing my rings and reusing stock pistons.

*note - only replacing rings due to precautionary measures
 

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Discussion Starter #11
yeah how long do rings last?


i'll be using water injection at anything above 12 psi, so i dont think detonation will get to bad
 

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Why don't more people use MKIV pistons? They are factory forged? The bore is a little bigger than ours, but honing can take care of that.
 

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Moderator, megalos ntabatzis!!
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1) they arent forged.
2) you can and some have
3) bore is already MAXXED on 7m ans cylinder walls are too close as it sits tock. overborring would just cause more heat and chance of preignition as well as bhg.
 

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SuprAng said:
1) they arent forged.
2) you can and some have
3) bore is already MAXXED on 7m ans cylinder walls are too close as it sits tock. overborring would just cause more heat and chance of preignition as well as bhg.

Ooopss....thought they were forged stock. There is this guy, Tuner M, and I saw him putting in MKIV pistons in an MKIII block. I should have asked him why, but he was busy. He really knows his stuff...had the only 10 second MKIV on the track during 2002 E-town meet.
 

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DFWSupras
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Well I have been looking into using 2JZ pistons too. I found a site that has some 86mm pistons and since the HKS MHG is 86mm I figured it would work. I believe a Supra in San Antonio TX did it. Had a 3.2L ticker on it too. Would that be the correct displacement?
 

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475RWHP 449TQ and climing
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suprang your statement is wrong. Toyota even sells .050 over pistons for the 7mgte. I have .040 over bored pistons thatnever over heat. Toyota will tell you that there is no problem. Go ahead give them a call. Amazes me where people get their info from!;)
 

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Question to suit.
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I still believe the stock pistons on a 2JZ ARE forged.....

Paisley put down over 900RWHP on a STOCK bottom end on one of his 2JZ cars.
 

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Moderator, megalos ntabatzis!!
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2j pisons are not forged, they are hypo... something treated, cant remember now, look it up, tehy are slightly better than the stock ones and not as good as forged.

how is my statement wrong? i didnt say it couldnt be done, i just said i dont think its a good idea, stock teh cylinder walls are too close, sorry for looking at this from an engineering perspective.\

its not ideal, no matter what you tell me.

Toyota will also tell you theres nothing wrong with a stock hg at 52lbs of torque, why dont you do that?



Goddamn, why do ppl have to be so blatently rude, M series engines are not jz's, they were built as a nice efficient 2L and stroked and bored out to shit, why do you think toyota changed the design of the jz? go look at one and tell me how close the cylinder walls are... whys that? you tell me. No wait i will, heat! the closer and thinner, the more heat. the less efficient. YOU CAN DO IT, didnt say you couldnt.

Last i checked going from an 83mm bore to an 86mm bore is pretty big difference, im not sure, and please do tell me what the thousands of an inch equates to for 2jz pistons, but i believe it to be more than .40
 

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25psi = 14" brakes :)
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SupraAng, thin material transfers heat to the coolant just fine. Add some thermal dispersant coatings, and you can overcome any cooling issues.
Also 85.5mm is possible on the 7m block with no issues at all. (Ask HKS, they have been doing it since the early 80's, and there are "Marine" 7m's out there stroked with the larger pistons too, displacment is about 3.4L I do belive.)
If my math is correct, and I'm not sure it is, I come up with about 3.14L for the 7m with 85.5mm bores, and a stock crank. Have been told the HKS pistons are actually lighter than stock ones, and there are no issues with stock rods to 7k with the 85.5mm pistons.
Only problem is the 1200/900usd for the pistons. (List/street price) Also ROSS will custom make any bore you ask for, but they they stock .40 overbore off the shelf. (Or so I read.)
Coatings will make your pistons last much longer in our Turbo cars. Keep the heat out of the piston, and rings, and you can run very high boost, and not fry your crowns/rings.
Stock pistons with 168k held up to 24psi runs for awhile. However, I believe detonation will kill any piston/ring if run for extended periods of time.
 
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