TURBO S2k
10-18-2007, 06:50 AM
#1
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TURBO S2k
Anyone turbo running just a vafc? im running 6lbs and comptech rising rate fuel pressure regulator on stock injectors anyone have settings out there or have an idea at what my fuel pressure should be set at? 45 psi? 48 psi? i know i should go to a stand alone but i want to run this untill i have enough for ems. Since i have a fpr can i add fuel with the vafc? or is it just used to - fuel? I've read somewhere that stock injectors are good for 7 lbs can someone clarify this. I was supercharged before will it make a difference as far as injectors or is it really just going to depend on my tune.
10-18-2007, 06:58 AM
#2
don't do it
wait until you can afford an EMS, or at least an Emanage. It will save you a blown motor if something goes wrong. Do you have a wideband? going to tune it on a dyno?
wait until you can afford an EMS, or at least an Emanage. It will save you a blown motor if something goes wrong. Do you have a wideband? going to tune it on a dyno?
10-18-2007, 07:28 AM
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the car is currently running with the turbo and vafc just need to tune to romp on the throttle. i have been driving very very easily on it for almost a week now without a blown motor. I have also been watching my wideband like a hawk.
10-18-2007, 07:53 AM
#5
If your on stock injectors, and ECU, the VAFC is only needed for WOT. Thats why your motor is fine. Try doing a 3-4 gear pull on the highway and see if its still ok 
As long as you know that a VAFC and Voltage clamp aren't even really adding fuel for the air seen by the map, keep running it.
Using a Variable rise FPR and VAFC on a supercharged setup is alot more reliable, considering the linear increase of Boost with RPM. There are no boost spikes, to 15psi, like on your turbo setup, or other little things that could increase the boost very quickly. This can become a big problem if you spike to 10-12 psi, but the FPR and VAFC have been setup to add fuel for 6 pounds, because you have no map sensor, the same fuel is sent and you run dangerously lean.
When you get it on the dyno and start tuning it, make sure to find out the duty cycle of your injectors. Depending on the efficiency of your setup, you might have already gone over their limits.
As long as you know that a VAFC and Voltage clamp aren't even really adding fuel for the air seen by the map, keep running it.
Using a Variable rise FPR and VAFC on a supercharged setup is alot more reliable, considering the linear increase of Boost with RPM. There are no boost spikes, to 15psi, like on your turbo setup, or other little things that could increase the boost very quickly. This can become a big problem if you spike to 10-12 psi, but the FPR and VAFC have been setup to add fuel for 6 pounds, because you have no map sensor, the same fuel is sent and you run dangerously lean.
When you get it on the dyno and start tuning it, make sure to find out the duty cycle of your injectors. Depending on the efficiency of your setup, you might have already gone over their limits.
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10-19-2007, 01:11 PM
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stock ecu is controlling timing i have done 3-4th gear pulles on the highway about 8 times today alone checking and rechecking a/f rations and my boost guage. Im holding a steady 5 lbs of boost with zero boost creep running straight off the wastegate spring without a boost controller. motor is sound as can be running, ideling, stop and go traffic over 50 miles back and forth to work everyday. so what else could go wrong is it just the boost spiking is what i should worry about? I've hit 8-10 psi but my map sensor picked it up threw a check engine light and ran in safe mode 3 times where my a/f would go straight to 10-11.0 at idle and would run like crap. Still no blown motor no ticking no funny sounds and i daily drive my s2k 2 and from work from VA-MD atleast 25-45 miles a day one way. Honestly i don't see a reason for the boost to spike unless i have a broken vacuum hose or something. Even when its cold it hasn't creeped yet.
10-19-2007, 01:20 PM
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if people can do 7 psi supercharged at redline on stock injectors. why cant i do 5 psi if my tune is right? Having a piggy back still lets the stock ecu compesensate for any "leanness" if thats a word. Anywhere else it doesn't compesensate to my understanding the rising rate fuel pressure regulator will add fuel when it sees boost. That combined with vafc-II to add or subtract fuel. i don't see why it wouldn't work. my a/f ratio's are 11.8-12.2 @ 3-5k rpm shoot to 12.7-13.0 right before vtec and dip down to 10.8-11.5 at redline. I think the ecu and rising rate fpr and vafc are working together just fine. I totally understand when you say the boost could spike somehow someway and the stock injectors couldn't compesensate for it but that would have to be a mechanical failure. If i upgrade to 650cc injectors it will be followed by an aem ems.