Toyspeed.org.nz Message Board

by **doublezero** » Tue Apr 28, 2009 11:00 pm

Hey guys,

I looked around the forum but couldn't find anything on pistons. Hopefully everyone can chip in and pass their knowledge to me.

I was looking at these TRD pistons and they have a high compression of 13.0
http://trdparts.jp/english/parts_engine-2zz-ge.html

Will 98RON be good enough these bad boys ?

cheers guys

by **KinLoud** » Tue Apr 28, 2009 11:51 pm

No - I think 13:1 pistons would need avgas and an aftermarket computer.
98 octane is almost a bit low for factory 2zzge engines (would run on 100 in Japan)

What are you wanting to achieve with your motor?

Ken
AUck
021 408 863

by **doublezero** » Wed Apr 29, 2009 12:48 am

I wanted to keep my car fully NA.

The TRD website showed some great gains with the simple mods that I already have but I have always wondered about them pistons.

by **Adamal** » Wed Apr 29, 2009 1:56 am

Yea, 13 is a bit high. It MIGHT be alright if you run a thicket head gasket to drop the compression a bit, but you wouldn't be wanting to give it any load at low RPM.

by **sergei** » Wed Apr 29, 2009 9:05 am

Adamal wrote:Yea, 13 is a bit high. It MIGHT be alright if you run a thicket head gasket to drop the compression a bit, but you wouldn't be wanting to give it any load at low RPM.

Thicker head gasket is misconception. Although it drops compression ratio, it does not drop the chances of detonation.

by **Adamal** » Wed Apr 29, 2009 10:07 am

I thought that if you drop the compression ratio, then it would decrease the chances of preignition.
Being that when you compress a gas, the byproduct is heat, and this is what causes detonation with a low octane fuel.
?

by **Sh0ckwave** » Wed Apr 29, 2009 11:20 am

Why would you buy expensive high compression TRD pistons just to lower the compression again with a thicker gasket

Its not hard to get avgas anyway, just a pain if its for an everyday car.

OMG so shiny! · by **Dell'Orto** » Wed Apr 29, 2009 11:23 am

Yeah 13:1 wouldn't really be feasible on pump gas, maybe if you backed the timing right off but what would be the point?

by **sergei** » Wed Apr 29, 2009 11:38 am

Adamal wrote:I thought that if you drop the compression ratio, then it would decrease the chances of preignition.
Being that when you compress a gas, the byproduct is heat, and this is what causes detonation with a low octane fuel.
?

It affects the squish area that basically affects how well the heat is spread and with impeded squish area you have more high temp. spots which increases chances of pre-ignition. Basically all the R&D that toyota did with combustion chamber goes out of the window when you use thick head gasket. It is kind of counter productive to have 13:1 pistons, then to lower it back to 12:1 (or whatever is stock) and increase the chances of detonation while decreasing the power (due to lower efficiency of combustion due to not enough squish) and fuel economy.

by **doublezero** » Wed Apr 29, 2009 12:26 pm

So maybe a Mahle piston set with a compression of 12.3:1 would work on our pump gas? or do I have to get a set with a compression of 12.0:1?

Gutted that I can't use the TRD ones

by **sergei** » Wed Apr 29, 2009 1:01 pm

doublezero wrote:So maybe a Mahle piston set with a compression of 12.3:1 would work on our pump gas? or do I have to get a set with a compression of 12.0:1?

Gutted that I can't use the TRD ones

What is wrong with stock?

Website · by **Bling** » Wed Apr 29, 2009 3:24 pm

Its not TRD :wink:

I love threads where posters give you no idea what their plans are then ask for useful advice :lol:

by **Adamal** » Wed Apr 29, 2009 4:34 pm

I plan on making a 10 second car. What would I need to do?

Website · by **Mr.Phreak** » Wed Apr 29, 2009 4:39 pm

Adamal wrote:I plan on making a 10 second car. What would I need to do?

Buy a 20v

by **doublezero** » Wed Apr 29, 2009 4:46 pm

lol I just saw on the trd parts website that the pistons could be put in with the simple mods to make some good gains. It would be a street car with the occasional track time.

All I was asking was whether the compression ratios would work with our pump gas.

I apologise that a simple question would create such a mocking.

Thanks for all those that answered my question. It is deeply appreciated.

by **Adamal** » Wed Apr 29, 2009 4:47 pm

Mr.Phreak wrote:
Adamal wrote:I plan on making a 10 second car. What would I need to do?

Buy a 20v

I said a 10 second car. I don't think I could handle a 5 second car.

by **Malcolm** » Wed Apr 29, 2009 5:39 pm

Dell'Orto wrote:Yeah 13:1 wouldn't really be feasible on pump gas, maybe if you backed the timing right off but what would be the point?

Our car runs 12.5:1 with up to 14psi of boost, no intercooler, on pump gas. It's all in the tune (well, a lot of it is).

Website · by **Bling** » Wed Apr 29, 2009 5:44 pm

doublezero wrote:All I was asking was whether the compression ratios would work with our pump gas.

I apologise that a simple question would create such a mocking.

Thanks for all those that answered my question. It is deeply appreciated.

Fair enough with the comments, but all the time people post up giving only half of the required information and people can't give the best possible advice. Its for your benefit we make you provide more information as people on here know a LOT about building powerful engines etc.

So it would be better to ask if its worth just changing pistons for a performance gain etc. Could save you a lot of money in the long wrong spent on the wrong mods. There are many ways to get gains from engines, each with different potential gains etc,

Just my 2c

by **sergei** » Wed Apr 29, 2009 6:11 pm

Malcolm wrote:
Dell'Orto wrote:Yeah 13:1 wouldn't really be feasible on pump gas, maybe if you backed the timing right off but what would be the point?

Our car runs 12.5:1 with up to 14psi of boost, no intercooler, on pump gas. It's all in the tune (well, a lot of it is).

Very normal for diesel engine, amazing for petrol...

by **NZ_AE86** » Wed Apr 29, 2009 9:55 pm

Malcolm wrote:
Our car runs 12.5:1 with up to 14psi of boost, no intercooler, on pump gas. It's all in the tune (well, a lot of it is).

Many other factors to be considered.

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