I need this confirmed: 7AFE or 4AFE with GZE pistons

[Dr Tweak]

I know that the GZE pistons will fit into a 7AFE or 4AFE, but what will the compression ratio be? It's been said that the piston sits higher thus raising the compression, is that true?

I'm talking with the stock FE head.

I did search with no definite answers.

[Kwanza]

Originally Posted by JDLangevin

I know that the GZE pistons will fit into a 7AFE or 4AFE, but what will the compression ratio be? It's been said that the piston sits higher thus raising the compression, is that true?

I'm talking with the stock FE head.

I did search with no definite answers.

It's not that the piston sits higher... I can't say for sure for the 4AF people... but in the 7AFE, 4AGZ pistons increased compression because of the stroke ratio and the compression chamber design of the the FE head. Because the 4AFE has the same/similar head design, I would imagine it would also increase compression, but probably not to the degree of the 7AFE. The 7AFE with 4AGZ pistons has been done in the 6th Gen Celica community and the guy that did it used the pistons to go n/a. He achieved estimated compression of over 11:1... I forget what 4AGZE pistons he used exactly... but it will probably be in that neighborhood depending which pistons are chosen (from 8:1-8:9:1)...

Also... 7AGE people have achieved 10+ compression with normal 4AGE pistons (9:4:1) with just the 7A's stroke ratio alone on the GE head... so it's not a big surprise...

[Dr Tweak]

Other threads I've been reading show that when the GE head is used, the compression is low, like 8.5:1... so when the FE head is used then it's higher?

More confirmation, anyone?

[Kwanza]

Originally Posted by JDLangevin

Other threads I've been reading show that when the GE head is used, the compression is low, like 8.5:1... so when the FE head is used then it's higher?

More confirmation, anyone?

Yes... it would be the opposite effect if the 7AFE pistons are used with the GE head...