VE values substancially less than stock
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From: Indianapolis
VE values substancially less than stock Hey guys while tuning my VE I noticed a huge drop in the values compared to the factory settings. My AFR is close to commanded so that is telling me that the numbers are close to correct for the engine as it stands but the lower numbers do not make sense to me. Why would the VE drop?
The engine is out of a 2002 WS6 with 100k miles. I have 1 3/4" long tubes, no cats and 2.5" true duel with an x pipe , TSP 228R 112 cam, 241 heads with a 5 angle valve job and a 4" pipe intake tract.
What could cause what I am assuming is a loss of efficiency? Is it mechanical or tune related? I didn't degree the cam when I installed it but have a wheel ordered if for nothing else than peace of mind.
Attached is a screen shot of the file compare from the base settings to the current VE tune and the current tune (set for SD)
The engine is out of a 2002 WS6 with 100k miles. I have 1 3/4" long tubes, no cats and 2.5" true duel with an x pipe , TSP 228R 112 cam, 241 heads with a 5 angle valve job and a 4" pipe intake tract.
What could cause what I am assuming is a loss of efficiency? Is it mechanical or tune related? I didn't degree the cam when I installed it but have a wheel ordered if for nothing else than peace of mind.
Attached is a screen shot of the file compare from the base settings to the current VE tune and the current tune (set for SD)
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From: Indianapolis
LSX those are both good suggestions. I will verify the injector curve is correct but this engine came out of the proverbial little old lady's car and was box stock with the PCM included. I have a pressure gauge at the rail that stays steady at 58#, at least while idling.
Is there a way to verify my AEM wideband? The exhaust smells rich when it shows rich and I pick up a little KR when it shows lean so its at least in the ballpark.
I guess the bottom line is I don't feel much improvement from the cam and I wonder what power I'm leaving on the table and where. The degree wheel comes in tonight so at least I can check that off the list.
Is there a way to verify my AEM wideband? The exhaust smells rich when it shows rich and I pick up a little KR when it shows lean so its at least in the ballpark.
I guess the bottom line is I don't feel much improvement from the cam and I wonder what power I'm leaving on the table and where. The degree wheel comes in tonight so at least I can check that off the list.
That cyl volume is correct for a 5.7L. Just multiply it x 8. The VE compare numbers don't look that out of line for a 228 cammed 5.7L. Although I doubt they got real data for those really low kPa rows. The lower rpm/mid map areas of a cammed engine usually have to be lowered anywhere from 75%-90%.
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Teching In
Joined: Jul 2013
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From: Indianapolis
LSX-I haven't enabled STFTs since I put the cam in, went straight to SD to do the VE tuning
2x and redtan- I assumed that I would drop some VE down low with the cam but kinda figured that the intake and exhaust flowing better would offset that some. The low kPa cells were hand smoothed to match the 3D graph. I only hit them when off the throttle to shift and it goes dead lean for a second. Is that something I should work on?
2x and redtan- I assumed that I would drop some VE down low with the cam but kinda figured that the intake and exhaust flowing better would offset that some. The low kPa cells were hand smoothed to match the 3D graph. I only hit them when off the throttle to shift and it goes dead lean for a second. Is that something I should work on?
Last edited by Naptown Dave; Apr 28, 2016 at 11:32 AM. Reason: add
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I have my DFCO disabled but my understanding is that it's just the nature of tuning a M6 car, it's going to spike lean when the throttle closes quickly. I can avoid it by slowly easing off the throttle for a few seconds before upshifting but it probably irritates the hell out of people behind me. I think there is some filtering available in HP v3 now but I'm still trying to figure out how to set up the basic graphs 
That cyl volume is correct for a 5.7L. Just multiply it x 8. The VE compare numbers don't look that out of line for a 228 cammed 5.7L. Although I doubt they got real data for those really low kPa rows. The lower rpm/mid map areas of a cammed engine usually have to be lowered anywhere from 75%-90%.
I have my DFCO disabled but my understanding is that it's just the nature of tuning a M6 car, it's going to spike lean when the throttle closes quickly. I can avoid it by slowly easing off the throttle for a few seconds before upshifting but it probably irritates the hell out of people behind me. I think there is some filtering available in HP v3 now but I'm still trying to figure out how to set up the basic graphs
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The cell count is about the only one I have my head around. Isn't there some time weighted and greater than/less than filtering available too?
Sounds like what I'm seeing isn't all that far off base. I'm going to degree the cam and change the plugs this weekend and see if that affects anything. I will report what comes up.
I appreciate your guys time and knowledge!
Sounds like what I'm seeing isn't all that far off base. I'm going to degree the cam and change the plugs this weekend and see if that affects anything. I will report what comes up.
I appreciate your guys time and knowledge!
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I used some redneck engineering to check my cam degree without pulling the FEAD over the weekend and they were within 1* of advertised on the card so I feel pretty good about the cam timing. I also swapped out the Bosch Platinum 2s for some NGKs.
Not much change in the log run file but I did notice my IATs were about 15-20 degrees higher than ambient on the highway and 30-50 in city driving.
Would that cause a "false" rich condition in open loop due to the hotter air being less dense? I noticed about a 1 AFR increase between highway and city driving.
I'm trying to not get too hung up on the VE numbers....
I ordered parts to get my intake out of the engine compartment, I always planned to but this just pushed me along.
Not much change in the log run file but I did notice my IATs were about 15-20 degrees higher than ambient on the highway and 30-50 in city driving.
Would that cause a "false" rich condition in open loop due to the hotter air being less dense? I noticed about a 1 AFR increase between highway and city driving.
I'm trying to not get too hung up on the VE numbers....
I ordered parts to get my intake out of the engine compartment, I always planned to but this just pushed me along.