Tuning Newb - VE values nearing 200%
Moderators: jsmcortina, muythaibxr
-
- Helpful MS/Extra'er
- Posts: 125
- Joined: Sun Oct 05, 2014 5:07 pm
Tuning Newb - VE values nearing 200%
I have been focusing on getting my Hemi reliable on the road and it has been running very well. The table still needs a bit of work, but my AFRs are inline for where they should be as I run the engine around the map.
Seeing numbers get up around 200% seems wrong, like I have a fuel calculation wrong. Can someone confirm my thought process? I have a pretty basic 5.7L Hemi with a cam, naturally aspirated with larger than stock injectors. I expect a proper VE table for something like this to not exceed ~115-130%, is that true?
Seeing numbers get up around 200% seems wrong, like I have a fuel calculation wrong. Can someone confirm my thought process? I have a pretty basic 5.7L Hemi with a cam, naturally aspirated with larger than stock injectors. I expect a proper VE table for something like this to not exceed ~115-130%, is that true?
1972 Plymouth 'Cuda - 5.7L Hemi w/T56 Magnum
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
-
- Super MS/Extra'er
- Posts: 17507
- Joined: Thu Apr 16, 2009 8:08 pm
Re: Tuning Newb - VE values nearing 200%
Try adding in "Incorporate AFR Target" - this requires slightly lower VE numbers.
The highest the table can go is 255.
The highest the table can go is 255.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
-
- Master MS/Extra'er
- Posts: 789
- Joined: Sun May 02, 2004 5:55 pm
- Location: Cleveland, Ohio
- Contact:
Re: Tuning Newb - VE values nearing 200%
One problem I had years ago when I had some very large VE numbers was a failing fuel pump. I had a rail-mounted gauge and everything seemed fine when I would look at it idling, even quick revs. But under load, the pump couldn't deliver enough fuel, pressure dropped, and the VEs got larger trying to compensate. Finally, I had a friend in the driver's seat brake-torque like doing a burnout while I watched the pressure gauge, and that's when the pressure drop was revealed. Just something to consider/verify.
-Dave
-Dave
'70 Chevelle ZZ383/700r4/3.73 MS3X, 36-1, LS Coils, Holley Stealthram -- success story
'92 Saturn 1.9 DOHC/5sp, MS3, Champcar racer success story
'79 Malibu DartSHP400/80mm/PG/3.55, MS3X/36-1/LS Coils -- success story
Porsche 944 S2 3.0 -- MS3X/36-1/LS Coils, 1:44s Mid-Ohio, Pro Course
'92 Saturn 1.9 DOHC/5sp, MS3, Champcar racer success story
'79 Malibu DartSHP400/80mm/PG/3.55, MS3X/36-1/LS Coils -- success story
Porsche 944 S2 3.0 -- MS3X/36-1/LS Coils, 1:44s Mid-Ohio, Pro Course
-
- Helpful MS/Extra'er
- Posts: 125
- Joined: Sun Oct 05, 2014 5:07 pm
Re: Tuning Newb - VE values nearing 200%
ChevelleFan wrote:One problem I had years ago when I had some very large VE numbers was a failing fuel pump. I had a rail-mounted gauge and everything seemed fine when I would look at it idling, even quick revs. But under load, the pump couldn't deliver enough fuel, pressure dropped, and the VEs got larger trying to compensate. Finally, I had a friend in the driver's seat brake-torque like doing a burnout while I watched the pressure gauge, and that's when the pressure drop was revealed. Just something to consider/verify.
-Dave
That's something on my list to check. I plan on adding a fuel pressure input to the ECU so that I can log it as well. Thanks
Sent from my iPhone using Tapatalk
1972 Plymouth 'Cuda - 5.7L Hemi w/T56 Magnum
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
-
- Helpful MS/Extra'er
- Posts: 125
- Joined: Sun Oct 05, 2014 5:07 pm
Re: Tuning Newb - VE values nearing 200%
I have it off because I had issues with what it was doing.Matt Cramer wrote:Try adding in "Incorporate AFR Target" - this requires slightly lower VE numbers.
The highest the table can go is 255.
I had a dead steady 13:1 AFR at idle and my idle cells in the Target AFR table were also 13:1.
When I turned on "incorporate AFR target", my idle AFR would increase by an entire point. I tested this several times and determined I was better off leaving the incorporate setting "off".
Sent from my iPhone using Tapatalk
1972 Plymouth 'Cuda - 5.7L Hemi w/T56 Magnum
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
-
- Helpful MS/Extra'er
- Posts: 125
- Joined: Sun Oct 05, 2014 5:07 pm
Re: Tuning Newb - VE values nearing 200%
If I change the injector flow rate in the fuel required calculation, is there a way to have my VE table scale according to that change?
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
1972 Plymouth 'Cuda - 5.7L Hemi w/T56 Magnum
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
-
- Site Admin
- Posts: 39621
- Joined: Mon May 03, 2004 1:34 am
- Location: Birmingham, UK
- Contact:
Re: Tuning Newb - VE values nearing 200%
Turning the setting on or off requires the VE table to be changed because it is multiplying in (or not) a scaling factor.goodysgotacuda wrote:When I turned on "incorporate AFR target", my idle AFR would increase by an entire point. I tested this several times and determined I was better off leaving the incorporate setting "off".
Normally it is best to enable it, then tune.
James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk
My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
-
- Super MS/Extra'er
- Posts: 6828
- Joined: Sun May 15, 2011 11:41 am
- Location: Walnut Creek, Calif. USA
Re: Tuning Newb - VE values nearing 200%
"Change the flow-rate"??? Does that mean they have not been flowed for rate and DT with your fuel system and injector drivers? If the have been flowed, and you know the correct number, then leave it at that. Anything else will only add to the confusion. If you haven't flowed them, then having odd VE values is kind of to be expected...
-
- Helpful MS/Extra'er
- Posts: 125
- Joined: Sun Oct 05, 2014 5:07 pm
Re: Tuning Newb - VE values nearing 200%
I don't have a flow rate number, but let's say I sent them out to get that.billr wrote:"Change the flow-rate"??? Does that mean they have not been flowed for rate and DT with your fuel system and injector drivers? If the have been flowed, and you know the correct number, then leave it at that. Anything else will only add to the confusion. If you haven't flowed them, then having odd VE values is kind of to be expected...
Once I get the number and input it into tunerstudio, will I need to retune my VE map? Or can it be scaled according to my changes?
Sent from my iPhone using Tapatalk
1972 Plymouth 'Cuda - 5.7L Hemi w/T56 Magnum
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
MS3 Gold Box, TunerStudio MS/MegaLogViewerHD user
-
- Super MS/Extra'er
- Posts: 6828
- Joined: Sun May 15, 2011 11:41 am
- Location: Walnut Creek, Calif. USA
Re: Tuning Newb - VE values nearing 200%
If you send the injectors out, you really need to send your MS and fuel system with them. Testing yourself is far more practical, and costs little. For flow rate, all you need is some way to measure either the weight or volume of fluid delivered during a period when the injector is held open. There are many common throw-away food containers that can be measured to give an accurate measure of volume collected, I like 5-qt ice cream tubs...
Yes, once accurate flow rate is known, the req_fuel may have to be corrected, and then the VE table should settle out (using VEAL) with more realistic values.
Yes, once accurate flow rate is known, the req_fuel may have to be corrected, and then the VE table should settle out (using VEAL) with more realistic values.