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Who has (or is doing) an NA-T on the forum?


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T.T. pistons with 3mm gasket = Too low

 

T.T. pistons with T.T. gasket = 8.5:1

 

T.T. pistons with N/A gasket = ?

 

N/A pistons with 3mm gasket = ?

 

N/A pistons with T.T. gasket = ?

 

N/A pistons with N/A gasket = 10:1

 

 

 

Which one's "Baby Bears bed"?

 

That would be a great table to populate...

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Have to say just read through this and its a great idea to get all na-t owners in a thread as will be great for advice and tips from the right people, i will be going na-t when get enough money just have to stop buying other parts for car and stay focused on na-t bits :)

 

Yea that was my aim dude. Even with the couple of short days the thread has been up its brought together some great threads & questions. Hopefully with everyone together this can be built on and a knowledge base made for everyone & if no article exists then a place to target ask other NA-T people. :)

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Oh and to add to David p's compression ratios... n/a pistons with tt(oem) headgasket. = around 9:2:1 give or take depending on if the head is machined .... tt pistons with n/a(oem) headgasket = around 9:1:1 again give or take dependant on the head.

 

For people wondering oem tt headgasket = 1.3mm and na oem = 0.6mm

 

Please feel free to correct me if I'm wrong anyone but pretty sure it's correct

Edited by Caineoo
correcting (see edit history)
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b;3573785']That would be a great table to populate...

 

Give that man a Blue Peter Badge. :rolleyes:

 

Oh and to add to David p's compression ratios... n/a pistons with tt(oem) headgasket. = around 9:2:1 give or take depending on if the head is machined .... tt pistons with tt (oem) headgasket = around 9:1:1 again give or take dependant on the head.

 

For people wondering oem tt headgasket = 1.3mm

 

 

Please feel free to correct me if I'm wrong anyone but pretty sure it's correct

 

 

I've updated one entry, I though stock T.T. was 8.5:1. ?

 

N/A gasket is thinner, can you calc that one?

 

T.T. pistons with 3mm gasket = Too low

 

N/A pistons with 3mm gasket = ?

 

T.T. pistons with T.T. gasket = 8.1:1

 

T.T. pistons with N/A gasket = 9.03

 

N/A pistons with T.T. gasket = 9.1:1

 

N/A pistons with N/A gasket = 10:1

 

 

 

Which one's "Baby Bears bed"?

Edited by David P (see edit history)
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Updated:

 

 

T.T. pistons with 3mm gasket = Too low

 

T.T. pistons with T.T. gasket = 8.1:1

 

T.T. pistons with N/A gasket = ?

 

N/A pistons with 3mm gasket = ?

 

N/A pistons with T.T. gasket = 9.2:1

 

N/A pistons with N/A gasket = 10:1

 

 

 

Which one's "Baby Bears bed"?

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Updated:

 

 

T.T. pistons with 3mm gasket = Too low

 

T.T. pistons with T.T. gasket = 8.1:1

 

T.T. pistons with N/A gasket = 9.03.1

 

N/A pistons with 3mm gasket = ?

 

N/A pistons with T.T. gasket = 9.2:1

 

N/A pistons with N/A gasket = 10:1

 

 

 

Which one's "Baby Bears bed"?

TT pistons / NA gasket 9.03.1

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If you have a stock non-VVTI NA then your stock compression is 10:1. Installing a stock TT HG will bring compression down to a boost friendly 9.2:1 which is ideal for running 17psi on almost any T4 turbo! TT HG and TT pistons will bring you down to 8.5:1 compression which is identical to stock TT compression! Non-VVTI 2JZ-GE blocks are identical to TT blocks with the exception of oil squirters in the TTs and lower compression hiper-pneumatic pistons, (NAs have cast pistons!)

 

I've personally installed a Eristic 1.3mm TT (stock TT) head gasket on a 3.4 stroker running a GT4788 turbo and it held fine under 38 psi of boost and the car went 8.38 @172 without spray! You can get one on ebay for like $40 shipped!

 

Stock NA headgasket - 0.5mm (10:1 compression good for 11-12 psi on 93 octane)

Stock TT headgasket - 1.3mm (9.2:1 compression good for 17-18 psi on 93 octane)

BoostLogic NA-T headgasket 2.5mm (8.5:1 compression good for 32-34 psi on 116 octane)

HKS TT headgaskets - 1.3mm, 1.6mm, 2.0mm, 2.5mm, 3.0mm

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Stock NA headgasket - 0.5mm (10:1 compression good for 11-12 psi on 93 octane)

Stock TT headgasket - 1.3mm (9.2:1 compression good for 17-18 psi on 93 octane)

BoostLogic NA-T headgasket 2.5mm (8.5:1 compression good for 32-34 psi on 116 octane)

HKS TT headgaskets - 1.3mm, 1.6mm, 2.0mm, 2.5mm, 3.0mm

 

Nice post fixcz :)

I'm guessing these are when using the N/A pistons?

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If you have a stock non-VVTI NA then your stock compression is 10:1. Installing a stock TT HG will bring compression down to a boost friendly 9.2:1 which is ideal for running 17psi on almost any T4 turbo! TT HG and TT pistons will bring you down to 8.5:1 compression which is identical to stock TT compression! Non-VVTI 2JZ-GE blocks are identical to TT blocks with the exception of oil squirters in the TTs and lower compression hiper-pneumatic pistons, (NAs have cast pistons!)

 

I've personally installed a Eristic 1.3mm TT (stock TT) head gasket on a 3.4 stroker running a GT4788 turbo and it held fine under 38 psi of boost and the car went 8.38 @172 without spray! You can get one on ebay for like $40 shipped!

 

Stock NA headgasket - 0.5mm (10:1 compression good for 11-12 psi on 93 octane)

Stock TT headgasket - 1.3mm (9.2:1 compression good for 17-18 psi on 93 octane)

BoostLogic NA-T headgasket 2.5mm (8.5:1 compression good for 32-34 psi on 116 octane)

HKS TT headgaskets - 1.3mm, 1.6mm, 2.0mm, 2.5mm, 3.0mm

 

That's good info mate but can I correct you on somthing.

 

A stock TT is 8.5.1 compression ratio using TT headgasket 1.3mm and TT pistons

 

Note the GE head has 0.30" machined out of it and the GTE head dose not. so that extra 0.30" gives a lower compression on the GE engine useing the TT pistons and TT HG.

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This question comes up constantly, so here are some pics to clarify.

 

Piston tops. The CC's are correct the valve pocket depths may be a little off. (measured with the tail of verniers)

image

 

Piston skirts showing cutout for oil squirter,and ring groove differences

image

 

Internal view with weights

image

 

GE piston & chamber

image

 

GTE piston & chamber. Since this pic was taken I have cc'd several other GTE chambers @ 45cc's.

image

 

GE combustion chamber recess

image

 

GTE combustion chamber (no recess)

image

 

GE inlet port face

image

 

GTE inlet port face

image

 

GE exhaust port face

image

 

GTE exhaust port face

image

GTE gasket on GE head

image

GE gasket on GTE head

image

 

Note the EGR flange is in the same position on both heads

 

 

 

 

 

GE combustion chamber & gasket

image

 

GTE combustion chamber & gasket

image

 

Both pistons sit .004”/.005” below the top of the block.

The GE combustion chamber is virtually a GTE chamber with a .030” recess machined at bore diameter. When you add the GE head gasket, .010” compressed, you get about .045” (1.14mm) piston to cylinder head clearance. With the GTE (no recess) the head gasket is .050”compressed and you get about .055” (1.4mm) piston to cylinder head clearance.

It is generally accepted that .032”(.8mm) is the minimum safe piston to cyl head clearance.

It is also generally accepted that when the piston to cyl head clearance exceeds .060”(1.5mm) the squish effect is severely diminished.

So, if you use a GE head gasket and a GTE head, .015”(.37mm) clearance, THE PISTON WILL HIT THE HEAD.

If you use a GTE head gasket and a GE head (NA/T) you end up with .085”(2.15mm) clearance and a less than effective squish.

The GE HG volume is 1.51cc & the GTE HG volume is 7.55cc a difference of 6.04cc

 

GE combustion chamber (head, gasket, piston) 55.5cc

+ GTE head gasket extra 6.04cc Gives .085”(2.15mm) squish

= 61.54cc = 9.12: 1

 

GE combustion chamber (head, gasket, piston ) 55.5cc

+ GTE piston extra 6.7cc Gives std GE squish .045"(1.14mm)

= 62.2cc = 9.03: 1

 

GTE combustion chamber (head, gasket, piston) 66.6cc

+ GE piston minus 6.7cc Gives std GTE squish .055"(1.4mm)

= 59.9cc = 9.34: 1

Edited by FOSTA (see edit history)
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I think I've filled the gaps in this one. :think:

 

 

T.T. pistons with T.T. gasket = 8.1:1

 

T.T. pistons with N/A gasket = 9.0:1

 

N/A pistons with T.T. gasket = 9.2:1

 

N/A pistons with N/A gasket = 10:1

 

Still trying to get my head around all this compression stuff but that looks to be heading the right way for a nice summary table :)

Nice one David :thumbs:

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Top and bottom of it is TT pistons and TT headgasket combo have been tried and tested a few times and because of it resulting in a lower compression than a stock TT and with it also affecting squish! It's apparanty too slugish off boost.

 

TT pistons - GE head gasket is good for 500bhp on pump fuel

 

TT head gasket - GE pistons is good for 500bhp on pump fuel

 

So if we are wanting a good responsive 600bhp NA-t we need somthing along the lines of TT pistons and a headgasket inbetween the stock thickness of the GE and TT. I'm thinking around 0.9-1mm of thinkness. ?

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b;3573943']Still trying to get my head around all this compression stuff but that looks to be heading the right way for a nice summary table :)

Nice one David :thumbs:

 

 

T.T. pistons with N/A head-gasket ticks all the boxes with OE components. :)

 

Capacity for enough boost to challenge a stock bottom end and gets my vote for "Baby Bears Bed". :trophy:

 

 

 

 

T.T. pistons with T.T. head-gasket = static compression 8.1:1 ~ squish over-size :slap:

 

T.T. pistons with N/A head-gasket = static compression 9.0:1 ~ squish correct :love:

 

N/A pistons with T.T. head-gasket = static compression 9.2:1 ~ squish over-size :slap:

 

N/A pistons with N/A head-gasket = static compression 10:1 ~ squish correct :senile:

Edited by David P (see edit history)
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T.T. pistons with N/A head-gasket ticks all the boxes with OE components. :)

 

Capacity for enough boost to challenge a stock bottom end and gets my vote for "Baby Bears Bed". :trophy:

 

 

 

 

T.T. pistons with T.T. head-gasket = static compression 8.1:1 ~ squish over-size :slap:

 

T.T. pistons with N/A head-gasket = static compression 9.0:1 ~ squish correct :love:

 

N/A pistons with T.T. head-gasket = static compression 9.2:1 ~ squish over-size :slap:

 

N/A pistons with N/A head-gasket = static compression 10:1 ~ squish correct :senile:

 

 

 

 

I don't think n/a pistons with t.t headgasket is squish over-size buddy.

 

People have been running it solidly and reliably for ages and you can push more boost than with the standard n/a with n/a compression.

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