Skim 2.3 pistons

[Simons]

Hi guys;

I want to make a 7A turbo engine, like a 3B but 2.3, and the question is how much can I skim the pistons? or what it's the skim limit? becouse I need to low the CR

I have the option to add a thicker head gasket if I can not skim to much the pistons, but I prefer to use stock rs2 head gasket with arp's....but I think that I will need skim+thick wasket

Thanks!

[Error404]

7A pistons are not forged so not really going to be very useful

[Rocco]

7A pistons are not forged so not really going to be very useful

are you sure Alex?

[diesel des]

I have saw pictures of melted 7a pistons used in a turbo engine at less than 300hp on safe fuel and timing......

[Rocco]

I have saw pictures of melted 7a pistons used in a turbo engine at less than 300hp on safe fuel and timing......

Maybe because they were crappy tuned?

[diesel des]

I don't think so. the guy was a bit of a vems legend who unfortunately is no longer with us...

[caterpillar]

its normal to hav high comp in newer engines... if you skim a 1-2mm its ok, but if you want really big power, i will use some JE or ROSS....

[Rocco]

I don't think so. the guy was a bit of a vems legend who unfortunately is no longer with us...

Do you mean Peter.? RIP

its normal to hav high comp in newer engines... if you skim a 1-2mm its ok, but if you want really big power, i will use some JE or ROSS....

Simon wants to run something like 450/500 hp.... And wants to use a 170 k. Kms 7A
Engine block with It's original pistons and crank

[diesel des]

yep Peter.

[Rocco]

yep Peter.

Being Peter.... He knew his stuff..

Then if I were Simons I'd overbore to 83 mm and use aftermarket forged pistons or directly build his spare stroker kit

[Error404]

going to 83mm brings its own set of problems - thin cylinder walls and the requirement for custom gasket and probably O-ringed block. I would say go with rebuilt 220mm block or go with the full stroker on a 236mm block

[caterpillar]

if you reboe a block from 81,00 to 83,00 ; its only redusing the sylinderwall( thickness) 1 mm....! and the syl wall are about 6,1-6,2 mm... so with 83,00 bore its 5,1-5,2mm...that not so thinn...

the old volvo redblock( b230) have about 3,5mm-3,7mm sylinderwall ... they do rebore it from 96,00 to 97,00.. and have big power in theese....

but there are som other isue in audi engines.. the neighbour sylinder...... you will have some problem with "hotspot" between the sylinders...even with the oring and mlsgasgeds....

[Simons]

Thanks for all guys

Resume, I also need pistons...

Caterpilar, did you see the "hotspot" problems in any 2.3 turbo? 1,5mm less between cylinder, respect 3B, I think it isn't too much to have a "hotspot" problems, also If you rebore the 3b to 81,5 will be 1mm less...also the CR it's very importand

[caterpillar]

the newer aftermarked injection kit doe fix the higer cr; and the thermic in the valve does go down.. so the exoust temp arent so high....1 mm redusing the rebore; no prob...81,5 +81,5...= 1mm less space betveen the syl...but 83,00 may be some trouble, its omly few ,, between the syl, 6,5 or 7mm

[Simons]

I can manage 82,5 pistons, -0,5 mm wall, compared to 3B bored limit

Do you know any guy who has a 2.3 turbo?