Max suggested boost?

[vcrpro3]

Have 91 octane max pump gas here in AZ, what max boost can safely be attained for performance street use (My car- 2.5 T-1 with factory intercooler setup,20%+ injectors,Alabama man header,TU 60 trim compressor/.48 a/r,port matched intake/exhaust,2-1/2 exhaust). Inquiring minds want to know.... Have a super 60 SMEC i may just trade off toward a proper custom cal for my needs

[cordes]

There are a ton of variables that go into it, but the most I would want to run on +20s would be 18PSI. That would be pushing them pretty hard with a setup like what you have.

[vcrpro3]

Was thinking about that much, but would probably be safer around 16psi considering the 91 octane thing.

[contraption22]

Take a drive around with your buddy. Have him hold a scanner in his lap. Have him watch the knock sensor output, and the knock retard while you drive. Turn up the boost until the slightest knock is deteted. Then back off a little.

There is your max boost.

[moparzrule]

With the super 60 cal I would keep it down because of the aggressive timing curves.

[vcrpro3]

With the super 60 cal I would keep it down because of the aggressive timing curves.

THe Super 60 is not being used,i want to sell or trade it. At this time i have MP SMEC in it and with my modded turbo and +20 injectors, i'm hitting overboost cut-out regularily and this is just with a heavy foot in street use . We have 91 octane here in Phoenix as opposed to mostly 92 octane pump gas with some locations having 93 octane. I'm willing to trade the for/toward a cal'ed SMEC but do not know the limitations on the 91 oct fuel.

[2.216VTurbo]

Good news is Al, if you blow up the motor, Turbos Unleashed is right there in Glendale with you Put a cut-out Grainger on the MAP line to avoid that pesky overboost cut out.

[moparzrule]

THe Super 60 is not being used,i want to sell or trade it. At this time i have MP SMEC in it and with my modded turbo and +20 injectors, i'm hitting overboost cut-out regularily and this is just with a heavy foot in street use . We have 91 octane here in Phoenix as opposed to mostly 92 octane pump gas with some locations having 93 octane. I'm willing to trade the for/toward a cal'ed SMEC but do not know the limitations on the 91 oct fuel.

Oh my bad I must have read that wrong the first time.
With a proper cal you should be able to run 18 PSI no problem on 91 octane. Back the initial timing off if you want to run more. Maybe put it back to 8* to run 20 PSI.
I prefer a 4.7V zener diode more than the bleed method for overboost cutout. Since you have a MP ecu you can run the 4.7V, if you had a stock ECU you would only be able to run a 4.3 diode in which case I would say go with the bleed.
I ran 17 PSI boost on my old T1 engine (log engine, non IC) with a MP ecu, squished FPR to give me 62 PSI static pressure, and a 4.7v diode on the map. Never broke a piston, 93 octane. Once I turned the boost to 18-19 PSI and timing back to 8 degrees, it was still OK. Bear in mind this is NON intercooled. So I think you will be just fine.

[john1320]

Oh my bad I must have read that wrong the first time.
With a proper cal you should be able to run 18 PSI no problem on 91 octane. Back the initial timing off if you want to run more. Maybe put it back to 8* to run 20 PSI.
I prefer a 4.7V zener diode more than the bleed method for overboost cutout. Since you have a MP ecu you can run the 4.7V, if you had a stock ECU you would only be able to run a 4.3 diode in which case I would say go with the bleed.
I ran 17 PSI boost on my old T1 engine (log engine, non IC) with a MP ecu, squished FPR to give me 62 PSI static pressure, and a 4.7v diode on the map. Never broke a piston, 93 octane. Once I turned the boost to 18-19 PSI and timing back to 8 degrees, it was still OK. Bear in mind this is NON intercooled. So I think you will be just fine.

Dam, timing and fp IS everything! I had no idea a log could be pushed that far on pump. Good thread!

[moparzrule]

Yeah running 10* timing and 17 PSI, an LT1 z28 camaro (auto with atleast exhaust) just barely pulled on me on the highway. I mean barely, from 60 to 110 he was 1 car length ahead. I was pissed.

[vcrpro3]

[QUOTE=2.216VTurbo;244093]Good news is Al, if you blow up the motor, Turbos Unleashed is right there in Glendale with you Put a cut-out Grainger on the MAP line to avoid that pesky overboost cut out.[/QUOTE

Actually, Chris and TU is something like 47 miles away across town,almost an hour away--The Phoenix Metro area is biiiiggg!