Dangers of running 30psi

soldave · 03-08-2009, 07:53 PM

Have put this in the Newbie section as it might just be a simple answer, but have a look at my situation first.

Am currently running a T04B 50-trim at 1.6bar/23psi (spiking to 1.8bar/26psi) which is clocking me pretty respectable 11.68s 1/4 mile times. Am using stock internals minus a HKS headgasket and ARP headstuds. Exhaust manifold is a Punishment Racing budget one. Still considering this GT3582R which I could get for a great price, and although signs are that I shouldn't get it, I do want to be sure.

I know that running about 22-23psi on this turbo is barely into its efficiency range and might not make it a streetable turbo for me. But what would be the main dangers of increasing boost to somewhere in the 26psi range? Would I be looking at the rods or pistons shattering, or would it be detonation that could kill the engine? The previous owner of this turbo is getting rid due to a rebuild caused by melting piston 4 doing 28-29psi on completely stock internals bar a headgasket.

I'm monitoring EGTs currently and am getting 1550F maximum, which I believe is about 100F lower than when things start to get in danger of melting. Am also monitoring knock and my counts are minimal.

Any advice on this (including "Just forget about it and go with the 50-trim") would be appreciated.

92_talon_awd · 03-08-2009, 07:59 PM

With all that you have such as headgasket, headstuds, and engine monitoring equipment, I would personally feel confident running 30psi. As long as your compression is tip top that is. I blew a chunk out of my stock piston at around 26-28psi but the #1 ring was leaking, I knew it, and the motor had 130k on it. Now that I have a fresh block with new pistons and rings, I can run high boost again. Just keep an eye on your afr's, egt's, and knock count and you should be forewarned of any major problems.

ed_dogg23 · 03-08-2009, 08:01 PM

Well Im on a stock 6b with 125k. My turbo is a 60 trim and ive been running 29-30psi for about a month now with no problemes. Id say as long as your tune is straight n you have other mods to support you should have no problem!

soldave · 03-08-2009, 08:14 PM

Need to do another compression check. A check a month ago reported marginally low compression in number 1 piston, but the engine was cold when they did the test. Wanted to warm the car up beforehand for the test (as have heard it's more accurate that way) but the garage was just about to close.

Quote:

Originally Posted by ed_dogg23

Well Im on a stock 6b with 125k. My turbo is a 60 trim and ive been running 29-30psi for about a month now with no problemes. Id say as long as your tune is straight n you have other mods to support you should have no problem!

Supporting mods include (but not limited to)
Walbro 255
750cc injectors
Stage 2 meth injection
Uprated intercooler
etc.

Full spec list (if anyone is bothered) is here.

ed_dogg23 · 03-08-2009, 08:22 PM

Only thing I would be concerned about would be your idc's. Bigger injectors should be in the mix.

siceclipse · 03-08-2009, 08:43 PM

make sure you have enough fuel

soldave · 03-08-2009, 08:51 PM

I was thinking about injectors, although with the 750s and a big meth nozzle with 75% meth I'm running a max IDC of about 75% at the moment.

ed_dogg23 · 03-09-2009, 11:11 AM

Quote:

Originally Posted by soldave

I was thinking about injectors, although with the 750s and a big meth nozzle with 75% meth I'm running a max IDC of about 75% at the moment.

Honetly I dont think thats bad at all. I bet the 750s would roll 30psi!