[civicek9coupe]

heres my setup:gsr i/e/h vafc tuned to 159whp and 118 ft lbs tourque. problem: car leans out in at 5800-6000 rpm right after vtec kicks in. ran a 15.4 best time with a 2.4 60ft. weighed in at 2620 with myself in it. wen i got home the spark plugs were gapped a little high about .52 with ngk 11.

 

[guitar1550]

do you have your a:f ratio maps from your dyno tuning session?

btw the correct way to read the plugs is RIGHT AFTER a WOT run, if you wait, the reading will be invalid

 

[civicek9coupe]

yes i do heres the deal after the tuning session:
3500=13.4
4000=13.2
4500=13.3
5000=13.8
5500=14.4
6000=14.8
6500=14.6
7000=14.6
7500=14.7
8000=14.6
thats the air fuel at the rpm with vtec kickin in at 5200

 

[guitar1550]

i think you're just reading the plugs wrong - see what others have to say about it though...

 

[DaBoyNBlu]

so... those were your tuned AFR's?

that seems awful lean for top-torque production.

or when you say "tuning session", you really mean, you dynoed it, and that's the AFR's you got, but couldn't really do anything about it.

 

[MichaelDelaney]

I'd hate to see what the engine temps were above 6000 rpm...

 

[yrag]

You might just need to get more fuel to the engine. What is your fuel pressure setting? You should be around 40lb or maybe a bit higher if you have stock injectors. You would like to be in the 12-13 A/F range at WOT on a dyno. I did some major engine work and found I needed to upgrade my injectors to 310s and installed a new fuel pressure regulator and pump. Solved the problem.

 

[MrNiceGuy]

yes i do heres the deal after the tuning session:
3500=13.4
4000=13.2
4500=13.3
5000=13.8
5500=14.4
6000=14.8
6500=14.6
7000=14.6
7500=14.7
8000=14.6
thats the air fuel at the rpm with vtec kickin in at 5200

Is that tuning or ruining? once VTEC kicks in at 5200rpm, your AF goes way up. Lots of air with not enough fuel is BAD.

 

[civicek9coupe]

yes that is my tuning session that the dyno reading from the 8th dyno run. so should i go back and say hey too much air not enough fuel with a result or no touque=car sucks fix it?

 

[MichaelDelaney]

what's your ignition advance set at? if it's too far you get this up top.

no just do it again to make sure it's not a heat-soaked run giving you false af ratios.

if you need more fuel up top, you can get a fpr but that'll seriously screw your lower rpm af ratios...leading to the need for a fuel controller to lean out the bottom rpms...

a money pit for sure...welcome to the addiction.

 

[95db8GSR]

a money pit for sure...welcome to the addiction.

lol...that says it all!!!!

 

[boobstar]

im not trying to be a jerk, but if you knew after your dyno that it was running lean, why did you ever leave the place doing the tuning. i would go back and not leave until you are closer to 12 at wot.

 

[MichaelDelaney]

uhh no.

af ratios are guides like a compass and should not be your final goal. torque is your final goal in tuning. af ratios in combination with engine temps should be guides as to whether you push the tuning further or back off. you don't tune to a specific af ratio number ever. they are just reference guides. 12:1 af ratio is WAY TOO RICH for N/A. FI? ok.

you want to look at your torque curve at those rpms.

if they are dropping and the engine temps are way off the roof add fuel and see what it does to the torque curve.

most people end up in between 13.0 to 13.8:1 depending on your motor and it's sealing ability (compression) and breathing.

14:1 is pushing it. the engine temps usually spike then.

this is why it's very important to try to keep the engine temps constant when you dyno tune and allow enough time in between sets of pulls. a rising temp because you heat-soaked the motor won't detect a true spike in temp from running too lean and it gives false hp/torque numbers. The motor has to be warmed up and at a constant temp but not heat soaked too much leading to rising temps.

the best place to put the wideband is before the cat and some aftermarket custom header makers will offer you an extra tuning bung at no extra charge (take the offer). For most people though they don't have this luxury and so we place the wideband in the exhaust tip deep into the muffler and assume the engine af ratio is altered by a constant amount by the cat.

I can tell you that for most people with i/h/e (no cat upgrade), they don't run too lean. In fact the stock ECU runs way too rich in partial throttle and in WOT. There's not enough advance and the injectors overfuel for the added flow you get from an i/h/e.

I'd check your MAP sensor to make sure it's functioning correctly and make sure your fuel injectors or fuel filter aren't bunged up.

running this lean is not usual for an i/h/e setup.

this is coming from 9 years of experience fooling around with these motors and I left i/h/c/e 5 years ago...

 

[boobstar]

i never meant to say that air/fuel was the goal in tuning i was simply stating that if he knew there was something he wasnt comfortable with when he left, why did he leave??? im not sure why i thought he was fi but you are right 12 would be quite rich for na. like md said there are a lot of things that go into tuning but if you are really upset those numbers now why didnt you just bring it up when you were there? i think you should be able to just go back and tell them you are a little nervous because of your a/f.

 

[civicek9coupe]

so my air fuel ratio should be lower around 13.5 or so.also today i messed around with my afc and put more fuel after vtec kicked in and it held rich all the way to 8000rpm. i raised the fuel pressure and put thew vtec unmatch to 8%, i dont really no wut that is about though

 

[MichaelDelaney]

PLEASE READ AGAIN

uhh no.

af ratios are guides like a compass and should not be your final goal. torque is your final goal in tuning. af ratios in combination with engine temps should be guides as to whether you push the tuning further or back off. you don't tune to a specific af ratio number ever. they are just reference guides.

you want to look at your torque curve at those rpms.

if they are dropping and the engine temps are way off the roof add fuel and see what it does to the torque curve....

I can tell you that for most people with i/h/e (no cat upgrade), they don't run too lean. In fact the stock ECU runs way too rich in partial throttle and in WOT. There's not enough advance and the injectors overfuel for the added flow you get from an i/h/e.

I'd check your MAP sensor to make sure it's functioning correctly and make sure your fuel injectors or fuel filter aren't bunged up.

running this lean is not usual for an i/h/e setup.

this is coming from 9 years of experience fooling around with these motors and I left i/h/c/e 5 years ago...

some people say shoot for 13.0-13.5:1 for N/A at each setting point but it varies from engine to engine. You really have to look at the torque change (if it budges in the direction you want) with the fuel adjustments. Some people need 13.8 or 14.0:1 af ratio. If the engine temp spikes, then I back off on the lean down. But I don't stop leaning down just because it's 13.5:1 af ratio. You have to look at thw whole picture in each situation: what the af ratio, torque, and engine temps tell you together.

The v/t unmt is the correction for the fuel in the rpms between the old VTEC switchover point to the new one.

eg. if the old VTEC was 4400 rpm, the nonVTEC fuel map goes to 4400 rpm and then the VTEC fuel map kicks in at WOT. If you move the VTEC to 5200 rpm, the old setup will have you running a VTEC fuel map from 4400 to 5200 rpm when you should have the nonVTEC fuel map there instead. You'll be running too rich in those rpms.

you should usually lean down with v/t unmt.

 

[MichaelDelaney]

AND....PLEASE READ AGAIN

what's your ignition advance set at? if it's too far you get this up top.

no just do it again to make sure it's not a heat-soaked run giving you false af ratios.

 

[gospeedracer182]

The thing I don't get about it is that the Vtec unmatch option in the VAFC is a percentage. How do you calculate how much of a percentage to set it to if you've moved your VTEC switchover point from 4400 to 5200? What percentage is that? Do you use the percentage of what 4400 is to 5200 or do you use redline as a calculation?

5200rpms is 15.4% higher than 4400rpms. So would I punch in +15% in the v/t unmt?