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Re: EFI WOT air fuel ratio for max power?
[Re: MR_P_BODY]
#1775196
03/09/15 02:24 AM
03/09/15 02:24 AM
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Joined: Nov 2004
Posts: 3,517
pacific northwest
Stroker Scamp
master
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master
Joined: Nov 2004
Posts: 3,517
pacific northwest
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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
footbrake N/A SB 408 Scamp 10.10 @ 132 street/strip
73 Duster 340 street strip 12.79 @ 105
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Re: EFI WOT air fuel ratio for max power?
[Re: dezduster]
#1775199
03/09/15 02:35 AM
03/09/15 02:35 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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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
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Re: EFI WOT air fuel ratio for max power?
[Re: dezduster]
#1775202
03/09/15 11:32 AM
03/09/15 11:32 AM
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Joined: Jan 2003
Posts: 16,924
NC
440Jim
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,924
NC
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Quote:
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.
For what its worth, my 2-cents.
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.
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Re: EFI WOT air fuel ratio for max power?
[Re: Thumperdart]
#1775205
03/09/15 01:32 PM
03/09/15 01:32 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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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
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Re: EFI WOT air fuel ratio for max power?
[Re: dezduster]
#1775207
03/09/15 04:09 PM
03/09/15 04:09 PM
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Joined: Aug 2003
Posts: 43,141
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,141
Bend,OR USA
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Quote:
Thank you for everyone's input. Looking for dyno time now.
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 ) size one number using Holley jets for best performance, leaner if higher, richer if lower 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: EFI WOT air fuel ratio for max power?
[Re: Cab_Burge]
#1775208
03/09/15 04:38 PM
03/09/15 04:38 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Quote:
Thank you for everyone's input. Looking for dyno time now.
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 ) size one number using Holley jets for best performance, leaner if higher, richer if lower
CAB.... ITS EFI
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Re: EFI WOT air fuel ratio for max power?
[Re: MR_P_BODY]
#1775209
03/09/15 06:11 PM
03/09/15 06:11 PM
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Joined: Feb 2003
Posts: 1,238
Nevada
dezduster
OP
pro stock
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OP
pro stock
Joined: Feb 2003
Posts: 1,238
Nevada
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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.
Last edited by dezduster; 03/10/15 01:17 AM.
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Re: EFI WOT air fuel ratio for max power?
[Re: dezduster]
#1775211
03/09/15 07:13 PM
03/09/15 07:13 PM
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Joined: Oct 2007
Posts: 4,206
New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,206
New York
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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.
Boffin Emeritus
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Re: EFI WOT air fuel ratio for max power?
[Re: polyspheric]
#1775212
03/09/15 09:45 PM
03/09/15 09:45 PM
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Joined: Feb 2011
Posts: 4,302
Nebraska
72Swinger
master
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master
Joined: Feb 2011
Posts: 4,302
Nebraska
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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.
Mopar to the bone!!!
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