Afr question...
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 5,656
Likes: 112
From: ocean springs mississippi
Afr question...
Installed new fuel system (dual walbro 450's /staged) with external fuel regulator....no change in tune....but,wideband drops to 10.0 under boost (3500+ rpm)? Does it need to be retuned due to fuel system? Tune should dictate fuel correct?
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 5,656
Likes: 112
From: ocean springs mississippi
It is tuned (non meth dependant) and am spraying methanol...could i just turn down meth a bit and just keep an eye on it obviously? Meth is surely adding fuel that car is not tuned for,will the computer make up for this? I figured the computer would only allow so much fuel to be used regardless of amount available...?
Le Mans Master
Joined: Jul 2010
Posts: 6,008
Likes: 723
It is tuned (non meth dependant) and am spraying methanol...could i just turn down meth a bit and just keep an eye on it obviously? Meth is surely adding fuel that car is not tuned for,will the computer make up for this? I figured the computer would only allow so much fuel to be used regardless of amount available...?
Safety Car
Joined: Jun 2005
Posts: 4,977
Likes: 256
From: St. Louis Missouri
Turn off meth? Meth is used for more than just supplementing an undersized fuel system. Is the fuel regulator boost referenced? You could be running more pressure now, which means you definitely need to do some re-calibrating.
Melting Slicks
Joined: Jul 2004
Posts: 2,844
Likes: 144
From: Northern Ireland
It is tuned (non meth dependant) and am spraying methanol...could i just turn down meth a bit and just keep an eye on it obviously? Meth is surely adding fuel that car is not tuned for,will the computer make up for this? I figured the computer would only allow so much fuel to be used regardless of amount available...?
And when you say 10.0 AFR.....what wideband are you using and does it actually display numbers lower than 10, or is it simply pegged at 10 ?
Any computer will only do what it has been told to do via the tuner. You've made major changes to the system, it will need re-tuned.
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 5,656
Likes: 112
From: ocean springs mississippi
It may have been tuned for your previous setup....but with a new fuel system, it has not been tuned
And when you say 10.0 AFR.....what wideband are you using and does it actually display numbers lower than 10, or is it simply pegged at 10 ?
Any computer will only do what it has been told to do via the tuner. You've made major changes to the system, it will need re-tuned.
And when you say 10.0 AFR.....what wideband are you using and does it actually display numbers lower than 10, or is it simply pegged at 10 ?
Any computer will only do what it has been told to do via the tuner. You've made major changes to the system, it will need re-tuned.
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Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 5,656
Likes: 112
From: ocean springs mississippi
Regulator is set to 58psi and is a return return style setup w/2nd pump being boost activated
Burning Brakes
Joined: Aug 2008
Posts: 855
Likes: 35
From: Katy/Houston Texas
Yes turn it off. He’s saying that it is not tuned dependant on meth so his tuner would have tuned the car on straight fuel then added the meth for safety and cooling. If is truly not meth dependent then he could shut the meth off and see what his afr is. Still rich re tune, decent afr just add some meth back into it. He will definitely need a re tune when he hooks up the boost referenced regulator which is going to increase the rail pressure under boost.
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 5,656
Likes: 112
From: ocean springs mississippi
It may have been tuned for your previous setup....but with a new fuel system, it has not been tuned
And when you say 10.0 AFR.....what wideband are you using and does it actually display numbers lower than 10, or is it simply pegged at 10 ?
Any computer will only do what it has been told to do via the tuner. You've made major changes to the system, it will need re-tuned.
And when you say 10.0 AFR.....what wideband are you using and does it actually display numbers lower than 10, or is it simply pegged at 10 ?
Any computer will only do what it has been told to do via the tuner. You've made major changes to the system, it will need re-tuned.
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 5,656
Likes: 112
From: ocean springs mississippi
That's what Im worried about. I am currently breaking in my new mantic clutch and am not really driving the car hard (just a couple short 2nd/3rd gear pulls)....trying to get clutch broke in before a dyno tune. Will i get fuel in oil/past rings?
Melting Slicks
Joined: Jul 2004
Posts: 2,844
Likes: 144
From: Northern Ireland
The bottom line is it needs tuned.
But if you're just driving gently/normally and mixtures seem fine there, then that should be ok until you can get it tuned
Last edited by stevieturbo; May 3, 2018 at 10:42 AM.
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 5,656
Likes: 112
From: ocean springs mississippi
Yea....just trying to break in clutch before tuning. Only did a few light 2nd/3rd gear pulls
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 5,656
Likes: 112
From: ocean springs mississippi
What kind of miles are people puting on these twin disc clutches to break them in? How can you tell when its good to run hard (mantic twin disc)?