rwhp at 15 vs 17psi?
06-08-2005, 01:34 PM
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rwhp at 15 vs 17psi?
I've been trying to find out weather or not I should run 17psi. I'm using k26 Vitesse chips. Does anyone know the difference between 15 and 17psi horsepower wise? Does 17psi give you substantially more power than 15psi, enough to warrant the added stress on the engine?
Thanks,
Josh
Thanks,
Josh
06-08-2005, 01:43 PM
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With a stock turbo you'd probably get about 20-25 more ft-lbs of torque and if your stock wastegate can hold 17psi to redline you'll probably get 20 more HP to the wheels.
Andy
Andy
06-08-2005, 04:01 PM
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Great,
Anybody know what fuel pressure for 17psi? Vitesse website just says 46+, and I don't have a air/fuel guage. I just need the exact fuel pressure to set it at 17 without blowing my head gasket.
Thanks guys
Anybody know what fuel pressure for 17psi? Vitesse website just says 46+, and I don't have a air/fuel guage. I just need the exact fuel pressure to set it at 17 without blowing my head gasket.
Thanks guys
06-08-2005, 04:14 PM
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On my Turbo S, I can't run over 16psi with stock injectors and a 3bar fpr, or it gets too lean. I'm already pushing right at 13:1 with stock injetors and Vitesse chips, EBC and LR DP wastegate. Personally, I wouldn't go playing around with anything higher than 15psi unless you've got a wideband 02, or access to a dyno with a wideband.
Find yourself a dyno with a wideband (or get one for your car), and do some tuning there to optimize your A/F. I've got a Rennbay AF9 gauge, which helps, but I still measured on the dyno and compared that A/F to what the the AF9 shows before I put any faith in it. Even with that, I'm still thinking about a wideband unit (after I do some 55lb injectors).
Find yourself a dyno with a wideband (or get one for your car), and do some tuning there to optimize your A/F. I've got a Rennbay AF9 gauge, which helps, but I still measured on the dyno and compared that A/F to what the the AF9 shows before I put any faith in it. Even with that, I'm still thinking about a wideband unit (after I do some 55lb injectors).
06-08-2005, 05:14 PM
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Originally Posted by awilson40
If you dont have a wideband to monitor your A/F you are best to
set it at 15 psi and leave it.
set it at 15 psi and leave it.
So you can monitor this that and the other....
Last edited by testarossa_td; 06-08-2005 at 07:05 PM.
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06-08-2005, 07:32 PM
#8
You should listen to these guys. The 951 is notorious for blowing headgaskets simply because guys just turn it up. You never know what your pump is doing, if it is tired, filter, injectors etc. - you can't see enough to take chances without the wideband info. 
06-08-2005, 07:58 PM
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Sure man - here's the tool panel and tool valance... 
Alpine white 931 hood behind, if anyone wants it.
Also - the crack in front is from Bridgehampton, of all places - you can't get cracks like THAT anymore.
Alpine white 931 hood behind, if anyone wants it.
Also - the crack in front is from Bridgehampton, of all places - you can't get cracks like THAT anymore.
06-08-2005, 08:04 PM
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And Mr Johns recommendation is also...if above 15psi, use race gas. So, as others have stated, I second, unless you have WBO2 info, don't push it up. Spend $500 or less and save yourself a headgasket, worse yet, piston/wall contact from all the water-steam that got pushed into your cylinders - then you have slightly more than $500 to spend. I think there are presently two motors being rebuilt right now from people pushing 17-18 without good info.
06-08-2005, 08:13 PM
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Each chip has its own FQS setting that the owner receives via email once he/she receives the chip. Some do match the settings as described on the website, some do not.
The K26 AFM chips allow you to run a bit higher than 15psi. I do not recommend it as you will not be able to tell much of a difference, you can record it on the dyno but may not feel it on the road. The K26 cannot keep up with engine demands, so why bother with anything over 15-16psi?
The K26 AFM chips allow you to run a bit higher than 15psi. I do not recommend it as you will not be able to tell much of a difference, you can record it on the dyno but may not feel it on the road. The K26 cannot keep up with engine demands, so why bother with anything over 15-16psi?
06-08-2005, 08:15 PM
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I think I'll play it safe for now. Just called a dyno shop and plan to take it in this weekend. That way I can see where I'm at as far as a/f ratio. Right now it's set to 15 at 43.5psi of fuel.