Posted By: dezduster
EFI WOT air fuel ratio for max power? - 03/09/15 06:01 AM
First would 11.8 be excessively rich for N/A engine at WOT?
EFI WOT air fuel ratio for max power?
Posted By: MR_P_BODY
Re: EFI WOT air fuel ratio for max power? - 03/09/15 06:11 AM
Yes... but you have to test to find the best ratio
Posted By: Stroker Scamp
Re: EFI WOT air fuel ratio for max power? - 03/09/15 06:24 AM
from everything I have read 12.5 -13 at WOT
That being said always tune for max MPH
has always helped me
keep an eye on your plugs
That being said always tune for max MPH
has always helped me
keep an eye on your plugs
Posted By: dezduster
Re: EFI WOT air fuel ratio for max power? - 03/09/15 06:27 AM
Mr P thank you for that quick response.
Going to check on some chassis dyno time Monday. The nearest dyno is 135 miles away so cant just pop in. This is a 520 ci mopar would like to dial it in quickly anyone have a suggestion number wise?
Mr Pbody you are up late sir.
Going to check on some chassis dyno time Monday. The nearest dyno is 135 miles away so cant just pop in. This is a 520 ci mopar would like to dial it in quickly anyone have a suggestion number wise?
Mr Pbody you are up late sir.
Posted By: dezduster
Re: EFI WOT air fuel ratio for max power? - 03/09/15 06:31 AM
Well tuning for MPH in a 5200 pound 4x4 is well exciting. We can do this but looking at some dyno time maybe next weekend.
Posted By: MR_P_BODY
Re: EFI WOT air fuel ratio for max power? - 03/09/15 06:35 AM
Quote:
Mr P thank you for that quick response.
Going to check on some chassis dyno time Monday. The nearest dyno is 135 miles away so cant just pop in. This is a 520 ci mopar would like to dial it in quickly anyone have a suggestion number wise?
Mr Pbody you are up late sir.
I would look at about 12.8 ... and move from there...
this is on EFI .. what one... it should be trying
to drive it much leaner than that.. or are you making
a fuel map for it
Posted By: 451Mopar
Re: EFI WOT air fuel ratio for max power? - 03/09/15 07:55 AM
Pump gas or Race fuel? Around here out "pump" gas is 10% Ethenol.
I'm adding a flex-fuel sensor to my FAST EFI, so it will compensate for the different percentages of alcohol in the gas.
I'm adding a flex-fuel sensor to my FAST EFI, so it will compensate for the different percentages of alcohol in the gas.
Posted By: Dragula
Re: EFI WOT air fuel ratio for max power? - 03/09/15 11:49 AM
Quote:
First would 11.8 be excessively rich for N/A engine at WOT?
No actually, 11.8 is just off a tad. I would lean it out to 12.2-12.4 and call it a day...
Posted By: 440Jim
Re: EFI WOT air fuel ratio for max power? - 03/09/15 03:32 PM
Quote:For what its worth, my 2-cents.
Well tuning for MPH in a 5200 pound 4x4 is well exciting. We can do this but looking at some dyno time maybe next weekend.
Assuming it is running on gasoline...
I would aim for about 12.2 at peak torque and 12.8 at peak horsepower. Drag race applications can often make a few more HP slightly leaner than that, but I like it a little rich (low 12's) lower in the rpm range.
These are just targets, and every application and engine may like slightly different.
Posted By: dezduster
Re: EFI WOT air fuel ratio for max power? - 03/09/15 05:04 PM
Thank you for everyone's input. Looking for dyno time now.
Posted By: Thumperdart
Re: EFI WOT air fuel ratio for max power? - 03/09/15 05:15 PM
This is how most seem to tune........focusing on wfo and forgetting OR not knowing how to tune the idle and cruise circuits which usually are rich. Getting a clean n mean carb takes work but well worth it and fuel type and ign. timing help also. I run unleaded vp 101 and it likes richer mixtures as in low 12 s where the leaded liked more timing and richer mixtures at least for my car....... 
Posted By: MR_P_BODY
Re: EFI WOT air fuel ratio for max power? - 03/09/15 05:32 PM
Quote:
This is how most seem to tune........focusing on wfo and forgetting OR not knowing how to tune the idle and cruise circuits which usually are rich. Getting a clean n mean carb takes work but well worth it and fuel type and ign. timing help also. I run unleaded vp 101 and it likes richer mixtures as in low 12 s where the leaded liked more timing and richer mixtures at least for my car.......
Its EFI.. and I'm thinking he is just trying to set
WOT and let the EFI control the rest
Posted By: Thumperdart
Re: EFI WOT air fuel ratio for max power? - 03/09/15 05:54 PM
Agreed on the efi but if he can map the tune, then it's that much sweeter.....
Posted By: Cab_Burge
Re: EFI WOT air fuel ratio for max power? - 03/09/15 08:09 PM
Quote:How much differences are there between the chassis dyno in Reno and where your pull off is going to be ? If similar, within 500 Ft of each other, tune it for best power on the dyno, if it is more than 500 ft difference you may need to change the jet(all of them
Thank you for everyone's input. Looking for dyno time now.
) size one number using Holley jets for best performance, leaner if higher, richer if lower 
Posted By: MR_P_BODY
Re: EFI WOT air fuel ratio for max power? - 03/09/15 08:38 PM
Quote:Quote:How much differences are there between the chassis dyno in Reno and where your pull off is going to be ? If similar, within 500 Ft of each other, tune it for best power on the dyno, if it is more than 500 ft difference you may need to change the jet(all of them
Thank you for everyone's input. Looking for dyno time now.
CAB.... ITS EFI
Posted By: dezduster
Re: EFI WOT air fuel ratio for max power? - 03/09/15 10:11 PM
Elevation here is 4000 Reno 4400.
So the 20th is the dyno date.
It's not my engine or truck and I'm excited about this.
So the 20th is the dyno date.
It's not my engine or truck and I'm excited about this.
Posted By: dmking
Re: EFI WOT air fuel ratio for max power? - 03/09/15 10:50 PM
my 2 cents is 13.7 to 14 driving on the flat cruise and 13.0 to 13.3 on the floor. check your plugs in both conditions.
Posted By: polyspheric
Re: EFI WOT air fuel ratio for max power? - 03/09/15 11:13 PM
Not exactly an answer, but
To find the best main jet using MPH:
1. if not a full 1/4 mile, use the fastest continuous pull in high gear
2. start with main jets too rich
3. reduce the mains 1 size at a time
4. each size drop should increase the MPH
5. when it doesn't, go back 1 step to the previous jets
Summary: you want the leanest jet that doesn't drop MPH (the point where +1 rich doesn't help, -1 lean slows down). Depending on your gearing, air temp, water temp, scoop shape, exhaust, and about 10 other factors it could be anywhere between 11.8 - 13.5.
To find the best main jet using MPH:
1. if not a full 1/4 mile, use the fastest continuous pull in high gear
2. start with main jets too rich
3. reduce the mains 1 size at a time
4. each size drop should increase the MPH
5. when it doesn't, go back 1 step to the previous jets
Summary: you want the leanest jet that doesn't drop MPH (the point where +1 rich doesn't help, -1 lean slows down). Depending on your gearing, air temp, water temp, scoop shape, exhaust, and about 10 other factors it could be anywhere between 11.8 - 13.5.
Posted By: 72Swinger
Re: EFI WOT air fuel ratio for max power? - 03/10/15 01:45 AM
You have to test it at a few different extremes. There is no set number until KNOW what it like. I ran my EZ Efi at 12.2 WOT for 2 months and right before I pulled the motor because it was sold, I tried 11.8 and it came alive. Nobody I researched ever went that rich with that system, my engine without a doubt liked it.
Posted By: 440Jim
Re: EFI WOT air fuel ratio for max power? - 03/10/15 02:42 AM
72Swinger,
That goes to show that some engine combos are more fuel efficient that others (BMSF). Some need more fuel for the same power, some do better at less.
That goes to show that some engine combos are more fuel efficient that others (BMSF). Some need more fuel for the same power, some do better at less.
Posted By: dezduster
Re: EFI WOT air fuel ratio for max power? - 03/10/15 05:25 AM
72swinger thank you for that information.
The dyno tuner I talked to is familiar with the EZ 2.0 EFI system. Says it shouldn't take more than an hour to get it crisp and safe. I have had the feeling its going rich at WOT. I may be dead wrong, that's fine as long as I am learning.
The dyno tuner I talked to is familiar with the EZ 2.0 EFI system. Says it shouldn't take more than an hour to get it crisp and safe. I have had the feeling its going rich at WOT. I may be dead wrong, that's fine as long as I am learning.
Posted By: TRENDZ
Re: EFI WOT air fuel ratio for max power? - 03/10/15 12:28 PM
EFI makes you re-think, or change your thinking on things. I always figured with efi, more power/higher rpm needs more pw. No.... Your fuel table SHOULD drop off in value beyond peak tq at the same map value axis. This is the most common mistake with new/ novice efi users.
A well tuned efi fuel map will show you exactly where your engine breathes the best.
Max cylinder fill occurs @ peak tq rpm. after that cyl fill drops off. the fuel must do the same, and at a higher degree. You end up using more fuel overall,due to more events per second, but the cycle is shorter in duration.
A well tuned efi fuel map will show you exactly where your engine breathes the best.
Max cylinder fill occurs @ peak tq rpm. after that cyl fill drops off. the fuel must do the same, and at a higher degree. You end up using more fuel overall,due to more events per second, but the cycle is shorter in duration.
Posted By: polyspheric
Re: EFI WOT air fuel ratio for max power? - 03/11/15 03:07 AM
Unless, of course, you need the extra fuel to reduce chamber temps.
Ooppsss....
There is no number, it's whatever works.
Ooppsss....
There is no number, it's whatever works.