Base Engine for a turbo project?

[Phat VR6 3]

9:1 for lower boost and drives stronger before turbo kicks in

8.5:1 for higher boost.. abit weaker off boast so again depends what your aiming for.. Run 9:1 unless your planning on running high boost but it doesnt really matter

[Kelster 0]

Phat VR6, what are you calling lower boost <14PSi ? Just curious as compression lowering is my next step.

[Phat VR6 3]

10- 12 psi should be fine on 9:1.. Not saying you couldn't push it more but personally im going to fit 8.5:1 a ill probaly end up turning it up as much as i can lol

Hears an interesting thread thats worth a read which helps you work out how much boost you can safly run using VAG.com

The lower the compression the less lightly knock will occur and timing getting pulled ect http://forums.vwvortex.com/zerothread?id=3607415

[MaidenVR6 26]

How much will it cost you to put turbo on a 24V engine? How much will the software cost? Have you seen the price's on 24V/R32 turbo parts compared to 12V turbo parts?

No doubt the 24V er more efficient than the 12V.

But the 12V have been out there for so many years now, that the turbo parts have decent price's.

And since you already have a OBD2 engine, go with that. Rebuild it, and have fun.

[Radostormvr6 2]

10- 12 psi should be fine on 9:1.. Not saying you couldn't push it more but personally im going to fit 8.5:1 a ill probaly end up turning it up as much as i can lol

Hears an interesting thread thats worth a read which helps you work out how much boost you can safly run using VAG.com

The lower the compression the less lightly knock will occur and timing getting pulled ect http://forums.vwvortex.com/zerothread?id=3607415

Im running 9:1 with 15psi and making 401bhp

[FishWick 21]

10- 12 psi should be fine on 9:1.. Not saying you couldn't push it more but personally im going to fit 8.5:1 a ill probaly end up turning it up as much as i can lol

It's also worth remembering the turbo's compressor flow when choosing a target boost pressure. PSI is PSI, regardless of turbo size, but a GT35 running 15psi will be pushing more air in than a GT30 running 15psi. So although 9:1 is probably safe with a GT30 running 12psi, it may not be with a GT35.

So I'd always run 8.5:1, or even 8:1 if you're planning on big boost pressures with big CFM turbos. The difference in off boost performance between 10:1 and 8.5:1 is negligable if the engine's setup right :-)