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Discussion Starter #1
i have heard from some mebers that the combustion chamber on the 2jzGE is larger than the GTE, therfore when using pistons made for the GTE into the GE, you actually lower the compression ratio even more than what the pistons are.
i am planning to go with some 9.0:1 compression ratio pistons, what head gasket should i use OEM N/A 2jzGE or or OEM TT 2jzGTE head gasket? What should i expect from these two head gaskets as far as compression ratio?
 

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It's been years since I underwent my conversion, but if I remember right the NA is higher compression as compared to the TT. Thats the reason most NA-Ts run thicker head gaskets, to lower compression. If you are going with TT pistons, I would suggest running just a stock NA gasket.
 

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It's been years since I underwent my conversion, but if I remember right the NA is higher compression as compared to the TT. Thats the reason most NA-Ts run thicker head gaskets, to lower compression. If you are going with TT pistons, I would suggest running just a stock NA gasket.

Thats kinda putting you right back were you began. TT pistons are low compression and NA pistons are high compression pistons. If you need a TT headgasket I have a couple.
 

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Sorry, meant to be more clear but was running out the door as I posted. I'm not sure about the differences between the TT/NA HG, just the differences in compression from the pistons themselves. Is the TT HG thicker as well? I was under the impression they were the same. I never considered a TT HG since I thought the heads were different?
 

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The heads are not really that difference either. You can drop a NA or TT head on either an NA and TT block PHYSICALLY.

By running TT pistons and TT headgaskets, you have the same compression ratio as a TT engine. I asked DaveH this probably 6 thousand times.
 

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By running TT pistons and TT headgaskets, you have the same compression ratio as a TT engine
^^^Yep that's right.

If you run TT pistons And an NA headgasket may get the best combo. 9ish:1 compression without meesing up quench which may be best for power on pump with a good tune

Or you can get 9:1 compression running NA pistons with A TT pistons.


All 3 combos work great you cant go wrong.
 

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I see alot of Na-t conversion kits coming with a 2-3mm headgasket to drop the compression. Alot easier to change the gasket than to changethe pistons.
 

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Thats what I ran, I didn't want to go near all the pistons with all the trouble I had with my NA-T project. I ran a BL 3.0mm HG. First one blew while tuning, though I think that was my bad by torquing to stock torque on the head with ARP studs, rather than the ARP torque. Second one seems to be holding up nicely.
 

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Discussion Starter #10
so i am going to run JE 86.5mm 9.0-1 TT pistons with the OEM TT gasket, if the NA head are not that different, does this mean i will be just below 9.0-1 or will my head make more difference than that. so if i understand this correctly, if i run these pistons with the NA gasket it should bump me up over 9.0-1 or will the thiner gasket and larger combustion chamber make up for the difference?
 

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Would it be fair to say that the NA pistons might actually resist detonation better than stock TTs? Due to the thicker ring land?
 

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Would it be fair to say that the NA pistons might actually resist detonation better than stock TTs? Due to the thicker ring land?
SHHHHH god damn it you want the TT people stealing more of our stuff!

:lol:

Alot of people run the 2.5mm HG with no problems, but its not really recommend when you want to start getting serious power.

I have a 2.5mm HG, but I am building another engine on the side....just waiting for winter and Vipec!
 

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what compression are the stock TT pistons?
that would depend on whether your ur using a TT or NA head gasket based on what was said earlier in the thread...still kinda confused myself at what compression each one has on the same set of pistons... but thats pretty much what this whole thread is about:confused:
 

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Discussion Starter #15
ok maybe this will help

question1 :what is the compression ratio with OEM TT pistons and TT head gasket and TT head?

question2: what is the compression ratio with OEM TT pistons and TT head gasket and N/A head?

question3: what is the compression ratio with OEM TT pistons and N/A head gasket and N/A head?
 
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