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High boost on stock longblock
Posted: Wed Apr 26, 2006 4:40 am
by Splinter
Im putting in my walbro 255lph pump tomorrow, and I was going to bump the boost up to 16psi and put in vikashs FCD
I'm intercooled (saab 900), and possibly putting in a waterspray (external)
Anyway.
16psi, am I gonna blow out the headgaskets or anything?
Posted: Wed Apr 26, 2006 4:45 am
by 555BCTurbo
If you are running the VF11 still, that will be waaaaaaaaay outside of the turbo's efficiency range, so I wouldn't take it past 12-13 psi with the stock turbo...it will just blow hot air past that.
Posted: Wed Apr 26, 2006 4:46 am
by Splinter
Isnt there quite a few people on the board running 15-16psi on the vf11?
That was my understanding
Posted: Wed Apr 26, 2006 4:54 am
by 555BCTurbo
You can, but there is really no point, as it will just blow mad hot air
Hot air=no more power
Posted: Wed Apr 26, 2006 4:56 am
by Splinter
Damn.
Well Im still gonna put in the FCD since I keep hitting boost cut when it surges sometimes (jumps up to 14psi on gear shifts when MBC is set to 11)
Posted: Wed Apr 26, 2006 5:03 am
by dzx
When my car was on the dyno we found it didn't make more power past 13psi. It was putting down 180wtq uncorrected though with the stock turbo.
Posted: Wed Apr 26, 2006 5:16 am
by 555BCTurbo
^ Thanks Dan for backing me up
Posted: Wed Apr 26, 2006 1:43 pm
by vrg3
Don't forget about keeping a decent air/fuel ratio.
Posted: Fri Apr 28, 2006 7:16 am
by Kelly
My car put down 220whp somewhere around 18psi on the VF11.
I dont know why, or how, but it did.
Stock maps, 92 octane.
Maybe thats why it smokes so much now.
Posted: Fri Apr 28, 2006 7:46 am
by Splinter
Any sign of those base maps for the smc yet?
Posted: Fri Apr 28, 2006 4:23 pm
by Matt Monson
Based on the modelling I did a few years ago with the boost maps and pressure ratios, etc. etc. I came to the conclusion that you SHOULD still see gains up to 15psi on the stock turbo. Since I sold my car before I ever got to test it, I don't have any real life tuning to back it up, so make your own judgements.
Also, choice of IC will impact things. That Saab IC is pretty small, and you may exceed the efficiency of the IC at a boost level that is lower than where the turbo itself starts to loose efficiency. Realistically, the only way to figure out where your set up runs best is get it on the dyno and take a handful of pulls at different boost levels...
Posted: Sat Apr 29, 2006 12:33 am
by my3awds
Isn't there too many factors to guesstimate how much psi you should use just based on your mods (ie octane level, air temps, elevation, etc)? I would go with a somewhat more accurate way then what 'most people use'...such as a Wideband, EGT, and O2V gauge. That way you don't go damaging the motor, and you get a closer idea of where you should be. It's too bad they don't have free logging software for the obd1 subies like they do for the dsms
