Is it possible to be running off the MAF with the MAF unplugged and fail set to 0hz or is the car definitely running off the VE?
Is it possible to be running off the MAF with the MAF unplugged and fail set to 0hz or is the car definitely running off the VE?
2002 WS-6, Built A-4, 3000 stall, Lid and K&N, ported TB, 220/224, .551, 114 LSA, roller rockers, LT's, 2.5" true duals with X-pipe, Koni adjustable front and Bilstein rears with Hotchkis springs, front bar and bushings, welded SFC's, boxed LCA's., Midnight Blue trimmed in silver, silver face gauges, custom hood bird, HPT (with lot's of tuning)
Originally Posted by Blue02WS6
100% guaranteed Speed Density mode....
vehicle doesnt even attempt use the MAF table if the MAF is Failed or disconnected
-Scott -
Been trying to figure out why my VE values are so big, many over 100 and just found a thread that said you could possibly not be in SD with the MAF failed, I am pretty sure I also unplugged mine, does the VE table look incorrect? The car runs pretty nice with the MAF unplugged, kinda peppy, idle is not quite as good as when running off the MAF.
2002 WS-6, Built A-4, 3000 stall, Lid and K&N, ported TB, 220/224, .551, 114 LSA, roller rockers, LT's, 2.5" true duals with X-pipe, Koni adjustable front and Bilstein rears with Hotchkis springs, front bar and bushings, welded SFC's, boxed LCA's., Midnight Blue trimmed in silver, silver face gauges, custom hood bird, HPT (with lot's of tuning)
Checked with the wide band today, it says the VE is pretty close and the NB's say the VE is close so they seem to agree with each other it appears, just can't believe there is that many cells over 100.
2002 WS-6, Built A-4, 3000 stall, Lid and K&N, ported TB, 220/224, .551, 114 LSA, roller rockers, LT's, 2.5" true duals with X-pipe, Koni adjustable front and Bilstein rears with Hotchkis springs, front bar and bushings, welded SFC's, boxed LCA's., Midnight Blue trimmed in silver, silver face gauges, custom hood bird, HPT (with lot's of tuning)
Do you have a 5 wire MAF? If so you need to leave it plugged in for the IAT. Whats the specs on the motor? My stock 5.3 with shorty headers, 3" exhaust and 4" intake is anywhere from 75-mid 90s. The stock tune was 20-25% lean.
I've read that it means the injector data is wrong.
multiple factors can contribute to a VE table being Higher than 100% on a naturally aspirated motor
typically its an issue with either the injector data(putting a smaller value in than the actual injector)
or it is related to IAT temps and the Bias table being wrong.
or if you have put in a larger engine than stock, and did not change the engine size in the tune
these are just a few things that are the most common reasons...
-Scott -
It's normal to have over 100 in the peak torque Map table cells. Just looking at a 100% stock 2003 Silverado SS that I tuned in SD mode (due to a bad Maf) and at 4800 RPM, the VE is 104.3. On a 2002 Camaro with a 6L, 224/228 cam & headers, the VE at 4800 RPM is 105.7. On my 2001 ZO6 with a 418, the VE is 115.9 at 5200 RPM.
Russ Kemp
its only normal on a GM vehicle because GM doesnt use a TRUE VE table....
its sort of correct....but their MAT functions are way off and make it read higher than what it should read.
-Scott -
I'm quite sure that my 418, and other cam & header cars are over 100% VE at peak torque.
Russ Kemp
again... Technically not possible according to physics unless you are forced induction......
its a flaw in the GM ECU calculations....
doesnt mean its wrong or that anything is wrong... Just means GM didnt make a real VE table.
-Scott -
Read up on inertial supercharging effect.
Russ Kemp
that includes this......
-Scott -
Inertial supercharging effect is referring to a NA engine.
Russ Kemp
yes...I know... technically...its forced induction from Speed......Just like "Ram Air" is air forced in faster by the speed of the vehicle...
-Scott -
Ok, so now you do agree that a NA engine CAN be over 100% VE.
Russ Kemp
again... technically...its not naturally aspirated if air is "Forced" into the cylinders.....
High speed driving is a method of forced induction...
but its all Just semantics that really dont matter here..
He is seeing cells in the 112~114 range...more than just Inertial supercharging would do...
we made 15psi on a 408 with an F1R and saw 116 in the VE table on an aftermarket system with a more accurate VE calculation and system...
all I'm saying.... is that GM has a sucky VE calculation...
its not uncommon to see values over 100 if you dont have everything exactly correct for Injectors, IAT calcs, Engine Displacement.....
-Scott -
If you only had 112-114 in your VE cells on a boosted engine, then your IFR table was too high and or the injector offset table was too high.
Yet you first said that a VE over 100% NA isn't possible unless "you are forced induction". Forced induction is not ram air, as you would need to be over 200 mph to create any real additional manifold pressure. Forced induction means turbocharging or supercharging.
Russ Kemp
It's not just speed that does it, cam timing events can cram in the extra air, air can't slow down and packs itself in. Hard to do but NASCAR has VE well over 100%, I've heard up to 140%. But I agree, something is just getting baked into the VE to make it higher.
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Exactly, and it's possible that the OP's fuel pressure might be dropping off, but it would show up as high VE values all the way to redline.
But my point is that telling someone that you can't have over 100% VE on a NA engine is not correct.
Russ Kemp
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