Whats the best A/F for nitrous WOT??

[VanWilder]

I just got my Zex 100 shot installed and it feels great but wasn't quite what I was expecting!! My bottle pressure was right at 950-960...I have a AEM Uego Wideband mounted in the rear o2 bung and at WOT it was reading 10.7:1...I was thinking that was a bit rich...I've always heard you wanna run around 11.5:1 to 12 flat for the most power...what do you guys think?! and if I get the tune leaned out to the 11.5 area will I feel a significant boost in power?!

 

[08gt4u]

if im not mistaken mines was between 11.3 to 11.5 at wot

 

[blue streak]

mine is 11.8. i have nos kit. 65 and 40 jet.

 

[08gt4u]

what are you spraying a 150?

 

[VanWilder]

what are you spraying a 150?

if you are refering to me I am spraying a 100 shot...I cant think of what jets I'm using off hand...I did a datalog the night I got the car back and sent it to Chris Rose (formerly of Tillman Speed) and I'm just waiting on him to send me a new tune leaned out a bit...he said he would pull about 3-4% of the fuel out of the tune and that should get me where I want to be...

 

[ChevyKiller]

If anybody gives you a 'set' number - they are crazy. There is no set a/f ratio - it really depends on your car and your tune. It is true that they are acceptable 'ranges' you want to shoot for, but you should really have your car dialed in tune wise perfectly.

For example, I am of the rich school myself and with boosted applications, I do not subscribe to the mid 11 doctorates. (at least not for 16+ psi)

I run my a/f in the mid to high 10 range and I think that is the best spot for big boosted apps, but for a mere 100 shot, I would shoot for the low 11 range personally. (11.2 - 11.4)

But that's my opinion.

 

[Fallenauthority]

IIRC if your car is running rich while spraying you dont want them to lean out the car through the tune, you need to adjust the fuel by lowering the fuel jet. Your a/f ratio needs to be on point in your tune without the spray, then you adjust the a/f while on the spray by changing the fuel jet.

 

[VanWilder]

IIRC if your car is running rich while spraying you dont want them to lean out the car through the tune, you need to adjust the fuel by lowering the fuel jet. Your a/f ratio needs to be on point in your tune without the spray, then you adjust the a/f while on the spray by changing the fuel jet.

I hear what you are saying...I have 2 tunes though...a NA tune and a separate Nitrous tune...in my NA tune I am at 31.5 degrees of timing and right at 12.8:1 A/F...when Chris made my nitrous tune he richened the tune about 4% and pulled 3.5 degrees of timing...when not spraying it doesnt have near the power my NA tune has...obviously...so by adjusting the fuel in the tune I wont be getting too lean when not spraying...I just dont want it too rich while spraying because I want to get some good power out of it

 

[VanWilder]

If anybody gives you a 'set' number - they are crazy. There is no set a/f ratio - it really depends on your car and your tune. It is true that they are acceptable 'ranges' you want to shoot for, but you should really have your car dialed in tune wise perfectly.

For example, I am of the rich school myself and with boosted applications, I do not subscribe to the mid 11 doctorates. (at least not for 16+ psi)

I run my a/f in the mid to high 10 range and I think that is the best spot for big boosted apps, but for a mere 100 shot, I would shoot for the low 11 range personally. (11.2 - 11.4)

But that's my opinion.

Thanks man!! Thats the area I am wanting it to be

 

[TheKurgan]

I hear what you are saying...I have 2 tunes though...a NA tune and a separate Nitrous tune...in my NA tune I am at 31.5 degrees of timing and right at 12.8:1 A/F...when Chris made my nitrous tune he richened the tune about 4% and pulled 3.5 degrees of timing...when not spraying it doesnt have near the power my NA tune has...obviously...so by adjusting the fuel in the tune I wont be getting too lean when not spraying...I just dont want it too rich while spraying because I want to get some good power out of it

Not the way I would of done it or had it done. No need to mess with the non nitrous tune except pulling the timing. The extra fuel supplied by the additional fuel line will richen it up enough. There was only a 2whp difference NA on the dyno after pulling 2 degrees for me. My A/F when spraying is right around 11.5.

 

[TurboPete]

Nitrous cars respond differently to a/f . A nitrous car will run harder and make more tq with a richer a/f . Ive always run nitrous between 10.8 to 11.2 . This has always made the most power and torq, better ET and MPH .
Run bottle pressure around 950 to 1000. I know that you hear people say run higher bottle pressure around 1100 but all your doing is damaging the rings on a stock motor .
You said the ZEX kit netted a 10.7 a/f , you should have left it alone , how much bottle pressure was that hit at .

Up the shot to 125 and make sure the bottle pressure is around 1000 make a hit in 3rd gear or 4th gear from a decent roll and check the a/f.



Pete

 

[TheKurgan]

Nitrous cars respond differently to a/f . A nitrous car will run harder and make more tq with a richer a/f . Ive always run nitrous between 10.8 to 11.2 . This has always made the most power and torq, better ET and MPH .
Run bottle pressure around 950 to 1000. I know that you hear people say run higher bottle pressure around 1100 but all your doing is damaging the rings on a stock motor .
You said the ZEX kit netted a 10.7 a/f , you should have left it alone , how much bottle pressure was that hit at .

Up the shot to 125 and make sure the bottle pressure is around 1000 make a hit in 3rd gear or 4th gear from a decent roll and check the a/f.

Pete

Just because it makes more power does not mean it's safer. If he ups that shot to a 125 and an A/F ratio of 10.8 then he is going to be seriously close to maxing out the stock fuel pump if not already.

 

[TurboPete]

Just because it makes more power does not mean it's safer. If he ups that shot to a 125 and an A/F ratio of 10.8 then he is going to be seriously close to maxing out the stock fuel pump if not already.

If you Max out the fuel pump , your not going to see 10.8 it will show it going lean . The nitrous kit is drawing fuel from the rail so if the pump cant keep up your a/f will go leaner. Besides a stock mustang gt with a 125 shot will not max out the pumps . You can run a 150 shot without a problem on the stock pumps.
He should go to the track run the same bottle pressure and make a pass with the original jetting which ZEX included in the kit and see the a/f at the top of the run . Lets say its 11.0 to 11.2 , I would leave it like that . If he changes the fuel jet to make it a tad leaner so the a/f is 11.6 to 11.8 I guarantee the car will go slower .

Every car is and runs different best thing to do is just run it at the track and have a few extra jets around . Just make sure you keep bottle pressure the same on all passes , and only change the fuel jet .2 up or down.


Pete

 

[TurboPete]

IIRC if your car is running rich while spraying you dont want them to lean out the car through the tune, you need to adjust the fuel by lowering the fuel jet. Your a/f ratio needs to be on point in your tune without the spray, then you adjust the a/f while on the spray by changing the fuel jet.

100 % Correct , only difference should be a timing change not a fuel change in the tune .

Unless your spraying at the track with c16 , then leave the timing as is .


Pete

 

[KITT]

I ran a 150 on stock pump no problems. Pulled 4* on timing and A/F was 11.4 on 93 octane. Pulled 2* with 100 octane. I set my bottle press transducer to 1100 because when you open the solenoid and the nitrous starts flowing the pressure will drop. In order to run at 1000psi I had to heat it to 1100. Just my experiences with nitrous. Run a plug one range colder than stock.

 

[VanWilder]

Nitrous cars respond differently to a/f . A nitrous car will run harder and make more tq with a richer a/f . Ive always run nitrous between 10.8 to 11.2 . This has always made the most power and torq, better ET and MPH .
Run bottle pressure around 950 to 1000. I know that you hear people say run higher bottle pressure around 1100 but all your doing is damaging the rings on a stock motor .
You said the ZEX kit netted a 10.7 a/f , you should have left it alone , how much bottle pressure was that hit at .

Up the shot to 125 and make sure the bottle pressure is around 1000 make a hit in 3rd gear or 4th gear from a decent roll and check the a/f.



Pete

Hmmm thats interesting I didnt know that about the A/F...making more power the richer it is...I do still have the original tune (the richer one) once I get the car on the dyno I will dyno both tunes and datalog the runs to see how close I am to maxing out the fuel pumps and see which one is the better of the two...I will also be getting to the track soon to test each tune as well...also when I ran my bottle pressure was showing right at 970-980psi on my digital gauge

If you Max out the fuel pump , your not going to see 10.8 it will show it going lean . The nitrous kit is drawing fuel from the rail so if the pump cant keep up your a/f will go leaner. Besides a stock mustang gt with a 125 shot will not max out the pumps . You can run a 150 shot without a problem on the stock pumps.
He should go to the track run the same bottle pressure and make a pass with the original jetting which ZEX included in the kit and see the a/f at the top of the run . Lets say its 11.0 to 11.2 , I would leave it like that . If he changes the fuel jet to make it a tad leaner so the a/f is 11.6 to 11.8 I guarantee the car will go slower .

Every car is and runs different best thing to do is just run it at the track and have a few extra jets around . Just make sure you keep bottle pressure the same on all passes , and only change the fuel jet .2 up or down.


Pete

I will try this

I ran a 150 on stock pump no problems. Pulled 4* on timing and A/F was 11.4 on 93 octane. Pulled 2* with 100 octane. I set my bottle press transducer to 1100 because when you open the solenoid and the nitrous starts flowing the pressure will drop. In order to run at 1000psi I had to heat it to 1100. Just my experiences with nitrous. Run a plug one range colder than stock.

I do have HT0s in the car now gapped to .035

 

[Nick@HSW]

my nitrous tune he richened the tune about 4%

Why would you do this? Allow the nitrous system to add enrichment or cut down the fuel jet size. IMO the only thing that should be touched in a "nitrous tune" for a mild application is the timing. Leave the fueling to the maf or fuel jet.

10.7 is way too fat for your application. You can't really give a solid number because honestly each car is going to react differently but try and target 11.3~12.3 on the spray. Always read your plugs to verify your results. Remember you can just as easily damage parts while too rich on nitrous as you can with too lean.

Nick

 

[VanWilder]

Why would you do this? Allow the nitrous system to add enrichment or cut down the fuel jet size. IMO the only thing that should be touched in a "nitrous tune" for a mild application is the timing. Leave the fueling to the maf or fuel jet.

10.7 is way too fat for your application. You can't really give a solid number because honestly each car is going to react differently but try and target 11.3~12.3 on the spray. Always read your plugs to verify your results. Remember you can just as easily damage parts while too rich on nitrous as you can with too lean.

Nick

Thanks for the input man!! I had Chris write me a new tune and he took about 3-4% of the fuel out...he said with this new tune I should be in the 11.7:1 area A/F based on the 10.7 it was showing previously...I havent had a chance to use it yet though because I have had issues with getting the bottle filled recently...should get it filled tomorrow hopefully and be able to test everything out. also I know I could probably search for this answer but since you brought it up what do I need to look for on my plugs to see whether its running too rich/lean??? and which plug is the best to check out first?! again thanks a lot for the help

 

[Nick@HSW]

Thanks for the input man!! I had Chris write me a new tune and he took about 3-4% of the fuel out...he said with this new tune I should be in the 11.7:1 area A/F based on the 10.7 it was showing previously...I havent had a chance to use it yet though because I have had issues with getting the bottle filled recently...should get it filled tomorrow hopefully and be able to test everything out. also I know I could probably search for this answer but since you brought it up what do I need to look for on my plugs to see whether its running too rich/lean??? and which plug is the best to check out first?! again thanks a lot for the help

You're going to want to pull all of them. Check with the forced induction guys to see if there is a hotter cylinder than others. Pete would probably know up above .

Check the ground strap and the base ring/last couple of threads. Coloring and distance up the ground strap are what we're looking for.

nick

 

[VanWilder]

You're going to want to pull all of them. Check with the forced induction guys to see if there is a hotter cylinder than others. Pete would probably know up above .

Check the ground strap and the base ring/last couple of threads. Coloring and distance up the ground strap are what we're looking for.

nick

Thanks a lot man!!! I'm assuming if the plugs are black its running too rich and if they are white its running lean??? correct me if I'm wrong...