club.liberty.asn.au

Hey guys, when i bought my beast it had been modified a bit. Has a VF34 turbo in it, front mount, tuned etc. Its running 17 - 18psi of boost at the moment, the bloke i bought it off said the engine would run 32psi safely. Which is a fair whack to a stock engine unless he had done same major work on it which he never mentioned. Seemed like one of those know it all - know nothing - bring it to your mates dodgy garage to make your car go faster kinda guy. So i need to know what amount of boost we can safely run whilst stock. Just spent 300 bucks on a fancy boost controller so i can turn it down to about 10psi for normal driving and press a button for "boost" mode for the rare occasion. So any help and advice would be much appreciated so i know im not gonna have a big hole in the engine

Which engine do you have? Or which car if you don't know?

EJ20T, 05 Liberty GT

Thinking this be an EJ20X

32 psi might be a tad optimistic. Running a vf34 you should be fine on 20 psi. But the vf34 will fall over about 4500-5000 rpm, and not spool up until about 3000-3500...

kiahatsiu wrote:32 psi might be a tad optimistic. Running a vf34 you should be fine on 20 psi. But the vf34 will fall over about 4500-5000 rpm, and not spool up until about 3000-3500...

Negative, spools up well before 3k which gets annoying. So what i am running is safe?

98 fuel or e85?

On 98 I wouldn't go past 18psi on stock internals and headstuds

On e85 that could stretch to 20

Actually scratch that. On 98 you could probably run 20psi but would be knock limited

On e85 your knock threshold is alot higher (almost non existent) but cylinder pressures would be more concerning and with the high static comp of 9.5:1 on the ej20y/x, and low lift/ low duration cams (meaning high dynamic compression at low revs to peak torque), e85 with mean best timing will lift heads at lower boost than on 98

If you went to 20psi on e85 but kept timing low (ie 1 or 2 degrees higher than 98 timing level), then you would be fine. But taking full advantage of e85's knock resistance (meaning higher timing) with 20psi will have higher cylinder pressures than your stock motor will like for long

Mick

dr20t wrote:Actually scratch that. On 98 you could probably run 20psi but would be knock limited

On e85 your knock threshold is alot higher (almost non existent) but cylinder pressures would be more concerning and with the high static comp of 9.5:1 on the ej20y/x, and low lift/ low duration cams (meaning high dynamic compression at low revs to peak torque), e85 with mean best timing will lift heads at lower boost than on 98

If you went to 20psi on e85 but kept timing low (ie 1 or 2 degrees higher than 98 timing level), then you would be fine. But taking full advantage of e85's knock resistance (meaning higher timing) with 20psi will have higher cylinder pressures than your stock motor will like for long

Mick

Yeah righto, im running 98, cant get e85 anywhere close and not tuned for it. What do most people on this site run on? Thanks for you help man gave me some piece of mind.

EJ20X ..... 16psi is all I would go.

I'm basically driving around a time bomb. 22psi ahoy.

HardwareBoB wrote:I'm basically driving around a time bomb. 22psi ahoy.

Your a daring man living on the edge like that haha

Stevo1111 wrote:

HardwareBoB wrote:I'm basically driving around a time bomb. 22psi ahoy.

Your a daring man living on the edge like that haha

Bye bye head gasket.....soon, you saw it here first

HardwareBoB wrote:I'm basically driving around a time bomb. 22psi ahoy.

That's mad

I ran 21.5psi on e85 for 15,000kms

Made 258awkw for a while haha

Cylinder pressures wouldve been friggen sky high

dr20t wrote:

HardwareBoB wrote:I'm basically driving around a time bomb. 22psi ahoy.

That's mad

I ran 21.5psi on e85 for 15,000kms

Made 258awkw for a while haha

Cylinder pressures wouldve been friggen sky high

Did you get my message about gearboxes Mick?