Compression Question
 

At what compression range is it safe to boost? Running stock A6 and want to know what to swap the pistons to in order to safely boost. Looking to boost under 10 have the turbo info and what not now need engine prep info. Help please.

Re: Compression Question
 

It depends on the turbo dumb ----. Read more before asking questions that have been asked a zillion times on every car forum known to man ::)

Re: Compression Question
 

commonly it's around 10:1 that problems arise, but as stated bluntly :6 above there's more to it than just that

Re: Compression Question
 

if you only plan on 10psi the stock a6 block should hold fine just do a compression test and leakdown test to make sure its in good condition and then pop on your turbo

then be sure to tune it dont use a fmu or afc hack or any ghetto ---- like that

Re: Compression Question
 

I've run (and will run again) 10.5:1 c/r on a stock block b16a at 14psi and higher before and never had any issues...it's all in the tuning. :6

Re: Compression Question
 

do you made a changing in cooling system ?

Re: Compression Question
 

Nope, other than going from my EF's full-size radiator down to an EG half-rad. I do use a product called water-wetter in the cooling system though, it breaks the surface tension of the coolant to aid in heat transfer.

Re: Compression Question
 

Thankx for the input.

Re: Compression Question
 

great work. did you went dyno befor ?

Re: Compression Question
 

damn thats high compression, im running 8.5:1 currently with plans to drop it to 8.1:1

but ive heard of guys running 12:1 properly tuned without a issue...

if you want to drop it just get some copper fat ass headgaskets, its the cheaper way, other than than you can bore out the combustion chamber on the head/s or use lower comp pistons...

10:1 is a tad high id be aiming for ATLEAST 9:1 to avoid detonation

Re: Compression Question
 

like slo crx said its all in the tuning you can run high compression and high boost just fine without detonation as long as its tuned properly

Re: Compression Question
 

Different engines respond different ways to boost. I know nothing of how efficient the A6 is.
10:1 on a 22RE engine - 4cyl 8 valve would be about the limit on pump gas with NO boost.

You can tune anything. Or run higher octane. Pulling timing helps, but it can result in high EGTs that are not sustainable for your pistons and/or vavles.

Consult the A6 experts to see how they're doing boost. It sucks being in the "learning curve" on a motor that hasn't been boosted before. The learning curve is expensive!

Re: Compression Question
 

Only dyno time I ever had on it was an sc61 setup on it @ 13psi, then dropped it down to 10psi for the street. Made 317 on a dynojet, and I figured it would be pushing the limits for a stock motor, so we detuned it a bit. Not to mention my 450's were maxed.The hg trick can work, but I wouldn't really advise it. It ends up moving the combustion process down into the cylinder more instead of in the chamber where it should be. Honda heads don't really have much room between the combustion chambers and the coolant jackets, so the most you can really do safely is clean up the castings to avoid hot spots that cause detonation. Lower c/r pistons is def. the best way to go lower.