Total timing with 87 octane, 2002 5.3 Z71 Silverado
01-30-2017, 08:26 AM
#1
Total timing with 87 octane, 2002 5.3 Z71 Silverado
Just recently have again played with the truck (HPTuners) a little bit here and there...I always have thought my old truck runs it's best on 87 octane...I tow my heavy car to the track at least a couple times a month, and use it for daily driver as well...
Truck has been very reliable and has always ran great, but subpar in the mileage department, since Day 1...
Usually 14-16 tops...12-13 normal mixed driving...
Basically it is a stock truck, infamous Ebay longtubes over SEVEN years now!
https://www.performancetrucks.net/fo...tailed-450962/
Homemade, proven cold air setup with stock airbox, 3" Dynomax exhaust, LS1 fan setup, ported stock throttle body, Corvette servo, etc...
Just curious what you guys are running, total timing wise, with similar setups???
Mine seems to like 21-22, and anymore, even with 93 octane (as a test), shows no real gain...and definitely not worth the 60-70 cents per gallon in price between the 87 and 93...
Truck has been very reliable and has always ran great, but subpar in the mileage department, since Day 1...
Usually 14-16 tops...12-13 normal mixed driving...
Basically it is a stock truck, infamous Ebay longtubes over SEVEN years now!
https://www.performancetrucks.net/fo...tailed-450962/
Homemade, proven cold air setup with stock airbox, 3" Dynomax exhaust, LS1 fan setup, ported stock throttle body, Corvette servo, etc...
Just curious what you guys are running, total timing wise, with similar setups???
Mine seems to like 21-22, and anymore, even with 93 octane (as a test), shows no real gain...and definitely not worth the 60-70 cents per gallon in price between the 87 and 93...
01-30-2017, 08:55 AM
#2
Just recently have again played with the truck (HPTuners) a little bit here and there...I always have thought my old truck runs it's best on 87 octane...I tow my heavy car to the track at least a couple times a month, and use it for daily driver as well...
Truck has been very reliable and has always ran great, but subpar in the mileage department, since Day 1...
Usually 14-16 tops...12-13 normal mixed driving...
Basically it is a stock truck, infamous Ebay longtubes over SEVEN years now!
https://www.performancetrucks.net/fo...tailed-450962/
Homemade, proven cold air setup with stock airbox, 3" Dynomax exhaust, LS1 fan setup, ported stock throttle body, Corvette servo, etc...
Just curious what you guys are running, total timing wise, with similar setups???
Mine seems to like 21-22, and anymore, even with 93 octane (as a test), shows no real gain...and definitely not worth the 60-70 cents per gallon in price between the 87 and 93...
Truck has been very reliable and has always ran great, but subpar in the mileage department, since Day 1...
Usually 14-16 tops...12-13 normal mixed driving...
Basically it is a stock truck, infamous Ebay longtubes over SEVEN years now!
https://www.performancetrucks.net/fo...tailed-450962/
Homemade, proven cold air setup with stock airbox, 3" Dynomax exhaust, LS1 fan setup, ported stock throttle body, Corvette servo, etc...
Just curious what you guys are running, total timing wise, with similar setups???
Mine seems to like 21-22, and anymore, even with 93 octane (as a test), shows no real gain...and definitely not worth the 60-70 cents per gallon in price between the 87 and 93...
1. Was the truck tuned after the longtube install/airbox install?
The VE/MAF table difference between stock manifolds and longtubes is enough to make the mileage suck.
Off idle timing makes a difference to. If you're only commanding 5-7 degrees of timing off idle and don't get into the 20's until PE mode, it takes more throttle to get you going. More throttle = more gas used = less mpg.
01-30-2017, 09:21 AM
#3
That's how we all learn, just get it and start asking questions. I do have a question.
1. Was the truck tuned after the longtube install/airbox install?
The VE/MAF table difference between stock manifolds and longtubes is enough to make the mileage suck.
Off idle timing makes a difference to. If you're only commanding 5-7 degrees of timing off idle and don't get into the 20's until PE mode, it takes more throttle to get you going. More throttle = more gas used = less mpg.
1. Was the truck tuned after the longtube install/airbox install?
The VE/MAF table difference between stock manifolds and longtubes is enough to make the mileage suck.
Off idle timing makes a difference to. If you're only commanding 5-7 degrees of timing off idle and don't get into the 20's until PE mode, it takes more throttle to get you going. More throttle = more gas used = less mpg.
My original HPTuner setup was a "serial port" version, and one of the first 300, lol. Back then, you got FOUR COMPLETE UNLIMITED MODEL year licenses included with the software...
Now you pay quadruple the money for just 4 car licenses...
Although the datalogging is an awesome feature.
anyway...
My truck was originally tuned (by me) over 7 years ago, when I did the whole Ebay header install thread, linked above. It was only getting 13mpg, bone stock w/mixed driving, when I bought it, roughly 10+ years ago.
Only recently re-tuned, after replacing the MAF meter.
My STFT's are always 1-2 when logged, and I actually have a bit more timing than stock tune. Attached below...Like I said, the truck seems to run very well, aside from subpar mileage. I was just mainly curious how much total timing others may be running, with an 87 octane tune....just for comparison sake. I'm basically running 3-4 degrees more timing than factory...across the board.
If I could find the secret to better mileage, or if you know it, or have ideas, please do share...
01-30-2017, 11:06 AM
#6
But, I have never seen more than high 16, ever.
I'd prefer to stick with the 87 octane tune solely because it is a to work and back home driver, much more than a tow vehicle, but am surely open to change.
I attached current tune, but evidently deleted my latest log. Will get one after work.
01-30-2017, 11:21 AM
#7
Saying it nicely, that VE needs a lot of work. The numbers in the table are very inflated, like numbers the vehicle could never see because it's a NA motor.
Perhaps when tuning the VE you never failed the MAF correctly and thus it's skewed all your numbers.
(Set the 3 MAF dtc's to fail on first error, set maf fail high to 0hz to put it in speed density. Remove MAF channels when tuning VE to prevent skewing)
Where you have that huge hump in the 120-130's, those numbers should still be the 80-90's near factory. Though the curve of the VE will be different than stock because of the airflow changes, just the numbers should not be so high like that.
Running a pretty lean AFR in PE on 87 also can reduce the amount of timing you can put into it. I prefer to aim for 12.2-12.3 to help prevent knock and get another 1-2 degrees of timing. I run 89 octane too because 87 runs worse in my truck.
Perhaps when tuning the VE you never failed the MAF correctly and thus it's skewed all your numbers.
(Set the 3 MAF dtc's to fail on first error, set maf fail high to 0hz to put it in speed density. Remove MAF channels when tuning VE to prevent skewing)
Where you have that huge hump in the 120-130's, those numbers should still be the 80-90's near factory. Though the curve of the VE will be different than stock because of the airflow changes, just the numbers should not be so high like that.
Running a pretty lean AFR in PE on 87 also can reduce the amount of timing you can put into it. I prefer to aim for 12.2-12.3 to help prevent knock and get another 1-2 degrees of timing. I run 89 octane too because 87 runs worse in my truck.
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01-30-2017, 01:19 PM
#8
Saying it nicely, that VE needs a lot of work. The numbers in the table are very inflated, like numbers the vehicle could never see because it's a NA motor.
Perhaps when tuning the VE you never failed the MAF correctly and thus it's skewed all your numbers.
(Set the 3 MAF dtc's to fail on first error, set maf fail high to 0hz to put it in speed density. Remove MAF channels when tuning VE to prevent skewing)
Where you have that huge hump in the 120-130's, those numbers should still be the 80-90's near factory. Though the curve of the VE will be different than stock because of the airflow changes, just the numbers should not be so high like that.
Running a pretty lean AFR in PE on 87 also can reduce the amount of timing you can put into it. I prefer to aim for 12.2-12.3 to help prevent knock and get another 1-2 degrees of timing. I run 89 octane too because 87 runs worse in my truck.
Perhaps when tuning the VE you never failed the MAF correctly and thus it's skewed all your numbers.
(Set the 3 MAF dtc's to fail on first error, set maf fail high to 0hz to put it in speed density. Remove MAF channels when tuning VE to prevent skewing)
Where you have that huge hump in the 120-130's, those numbers should still be the 80-90's near factory. Though the curve of the VE will be different than stock because of the airflow changes, just the numbers should not be so high like that.
Running a pretty lean AFR in PE on 87 also can reduce the amount of timing you can put into it. I prefer to aim for 12.2-12.3 to help prevent knock and get another 1-2 degrees of timing. I run 89 octane too because 87 runs worse in my truck.
Like I said, I haven't touched it in about 7 years, so no doubt rusty, and probably didn't fail the meter properly, as you mentioned...
Maybe a "do-over" is needed?
Last edited by rel3rd; 01-31-2017 at 06:11 AM.
01-31-2017, 04:40 PM
#9
FWIW, I took my stock VE settings and started over from scratch...right off the bat it was adding 20 to 25% or more, fuel, and after a half dozen logs and reflashes, the numbers ended up pretty much identical to my VE table above that "needs work"...
So, do I "give it what it wants", or is something else possibly going on?
Just for the heck of it, I went to the HPTuners repositor and downloaded about a half dozen similar modes trucks and you are cirrect, they are much lower in the VE numbers than me....
???
So, do I "give it what it wants", or is something else possibly going on?
Just for the heck of it, I went to the HPTuners repositor and downloaded about a half dozen similar modes trucks and you are cirrect, they are much lower in the VE numbers than me....
???
01-31-2017, 05:03 PM
#10
What way are doing these changes to the VE?
Are you using a wideband with an AFR error or using the LTFT + STFT method?
Making sure to apply the changes using the paste special % by half.
I have a feeling that if you are using fuel trims those headers are throwing your numbers out of whack because the o2 sensor placement. I prefer using a wideband to tune the VE and MAF.
Even post the tune file you were using while logging to see if something is causing it to be off.
Are you using a wideband with an AFR error or using the LTFT + STFT method?
Making sure to apply the changes using the paste special % by half.
I have a feeling that if you are using fuel trims those headers are throwing your numbers out of whack because the o2 sensor placement. I prefer using a wideband to tune the VE and MAF.
Even post the tune file you were using while logging to see if something is causing it to be off.