lean tip in.....
05-25-06, 12:34 AM
#1
lean tip in.....
getting a slight stumble and lean tip in with my new setup. i have 550/1600's. i did some searching but couldnt find the cause of the leaned tip in. its very slight. it goes lean real quick then its fine. any help appreciated.
05-25-06, 06:40 AM
#5
Yup, if you have a power FC, and access to a datalogit - you want to add roughly 3-8% fuel in the whole N06, N07, N08 - I did 4% in N06, 8% in N07 and 3% in N08 rows, assuming your P&N settings are default. If you have a datalogit, I can walk you through it - pretty simple.
05-25-06, 09:49 AM
#7
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I would add fuel to the accel enrichment first. Your description makes it sound like it happens when you change the % the throttle is open. Set the map to be ideal for steady state and play with the accel values to compensate for sudden movements of the throttle. That is how I tuned my car. It will give you the best mileage and should take care of the problem.
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05-25-06, 08:09 PM
#12
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leaner doesn't necessarily mean better gas milage. it does to a point, then th engine starts getting less efficient.
2 things that really effect how lean you can realistically run it are port overlap (the less the better), and compression (more the better).
other than that, negative split is fun to play with for firing off super lean mixtures. i've run my fd all the way to the high 16's before it would miss, but i could feel the power dropping off when it got much leaner than the low 15's and i had to use a higher pedal position to maintain cruise.
darren, under cruising conditions...say <4krpm and 8"+ vacuum, the engine will misfire before it detonates.... actually, (now that i think about it) if you can MAKE it detonate under those conditions, i'll give you a cookie.
2 things that really effect how lean you can realistically run it are port overlap (the less the better), and compression (more the better).
other than that, negative split is fun to play with for firing off super lean mixtures. i've run my fd all the way to the high 16's before it would miss, but i could feel the power dropping off when it got much leaner than the low 15's and i had to use a higher pedal position to maintain cruise.
darren, under cruising conditions...say <4krpm and 8"+ vacuum, the engine will misfire before it detonates.... actually, (now that i think about it) if you can MAKE it detonate under those conditions, i'll give you a cookie.
05-25-06, 09:04 PM
#13
Originally Posted by GUITARJUNKIE28
leaner doesn't necessarily mean better gas milage. it does to a point, then th engine starts getting less efficient.
2 things that really effect how lean you can realistically run it are port overlap (the less the better), and compression (more the better).
other than that, negative split is fun to play with for firing off super lean mixtures. i've run my fd all the way to the high 16's before it would miss, but i could feel the power dropping off when it got much leaner than the low 15's and i had to use a higher pedal position to maintain cruise.
darren, under cruising conditions...say <4krpm and 8"+ vacuum, the engine will misfire before it detonates.... actually, (now that i think about it) if you can MAKE it detonate under those conditions, i'll give you a cookie.
2 things that really effect how lean you can realistically run it are port overlap (the less the better), and compression (more the better).
other than that, negative split is fun to play with for firing off super lean mixtures. i've run my fd all the way to the high 16's before it would miss, but i could feel the power dropping off when it got much leaner than the low 15's and i had to use a higher pedal position to maintain cruise.
darren, under cruising conditions...say <4krpm and 8"+ vacuum, the engine will misfire before it detonates.... actually, (now that i think about it) if you can MAKE it detonate under those conditions, i'll give you a cookie.
I just don't like running that lean period... not in cruise, not ever... but thats me. Before the kan tune, my cruise was 15.0-14.7 which yielded pretty good gas mileadge. Now with Steve-O's rich tune.. I get crap mileadge, but I don't care. LOL
05-25-06, 09:12 PM
#14
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I run 15.5 at crusing speed and haven't had a problem with it. I used to drive a 480 mile road trip once every 2 weeks. My mileage was 22-24 mpg and I typically cruise at around 75-80. Near the 0/0 vac/pressure row my afrs are in the 12s.
I think the chance of doing any damage in vac at low rpm is remote. When I did my first engine swap several years ago my friend that was *helping* me hooked my ignition coils up in the wrong order. Believe it or not the car ran fine but had severe misfire as soon as the manifold pressure became positive. Steve Kan witnessed it. It sounded like someone running nails over a chalk board. If that didn't do any damage I can't see how 16:1 could under light load.
I think the chance of doing any damage in vac at low rpm is remote. When I did my first engine swap several years ago my friend that was *helping* me hooked my ignition coils up in the wrong order. Believe it or not the car ran fine but had severe misfire as soon as the manifold pressure became positive. Steve Kan witnessed it. It sounded like someone running nails over a chalk board. If that didn't do any damage I can't see how 16:1 could under light load.
Last edited by CCarlisi; 05-25-06 at 09:18 PM.
05-26-06, 12:41 AM
#15
dhahlen, richend up the n6-8 and the surrounding areas and it worked good. my cruise afrs were a little to lean mid 16's and some 17's after driving today. after richen i got it to mid 14's, which sounds and runs a little smoother and no more lean tip in.
05-26-06, 07:06 AM
#16
Originally Posted by smg944
dhahlen, richend up the n6-8 and the surrounding areas and it worked good. my cruise afrs were a little to lean mid 16's and some 17's after driving today. after richen i got it to mid 14's, which sounds and runs a little smoother and no more lean tip in.
05-27-06, 02:02 AM
#17
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Originally Posted by dhahlen
Dave, I wasn't worrying about detonation under cruise. You show me someone that blew an engine from cruising or letting it idle and I'll show you a man with 8 *********.. gross.
I just don't like running that lean period... not in cruise, not ever... but thats me. Before the kan tune, my cruise was 15.0-14.7 which yielded pretty good gas mileadge. Now with Steve-O's rich tune.. I get crap mileadge, but I don't care. LOL
I just don't like running that lean period... not in cruise, not ever... but thats me. Before the kan tune, my cruise was 15.0-14.7 which yielded pretty good gas mileadge. Now with Steve-O's rich tune.. I get crap mileadge, but I don't care. LOL
steve's a good tuner. i don't know why he would richen up the cruise stuff.
05-27-06, 07:19 PM
#18
Originally Posted by GUITARJUNKIE28
steve's a good tuner. i don't know why he would richen up the cruise stuff.
Also, steve wasn't focusing too much on cruise... just for boost and power. He also tunes for drivability if you ask him. But I was just doing the dyno/power tune.
05-28-06, 10:25 AM
#20
Old [Sch|F]ool
Originally Posted by GUITARJUNKIE28
i've run my fd all the way to the high 16's before it would miss, but i could feel the power dropping off when it got much leaner than the low 15's and i had to use a higher pedal position to maintain cruise.
One of the benefits of EGR is increased fuel economy by decreasing intake manifold vacuum, thereby decreasing engine pumping losses.
Upshot: running at heavier throttle for a given load *might* result in better economy, but only instrumentation could tell for sure. It'd be interesting to see what richer and lower throttle opening vs. leaner but more throttle do for consumption.
05-28-06, 01:45 PM
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i never got too too deep into the datalogging, but i've done a tank or two of gas running each way, and the current motor (9:1) in the fd (built with spare parts, mind you) got the best fuel economy right around stoic. the new motor actually has all the parts within spec, all new seals, etc... and it has a cosmo primary (they have less overlap, for those of you that don't know).
i was going to use renny rotors and go for big fuel economy, but i realised that 8.5 rotors will save money. with the 8.5 rotors, i'm aiming at 400whp on 87 octane + water/meth just to see if i can do it, but i should have absolutely no problems running it at 10-12 psi on a daily basis...even without the injection. so $.20/gallon is going to save me more money on fuel than the 1/2-1mpg increase from the high-comp rotors.
back to the topic-- not sure what it's going to do for split and economy, but the motor that's in there was intended to be a temporary solution so i could drive the thing. the new motor makes factory compression. that should make quite a bit of difference, even with the lower compression ratio.
if i get a bunch of extra time and money, i'll set the cruise control on the dyno and i can play around with how lean lean i can get it and at what point it loses its benefits. but in order to do that really well, i'd take the vac line off the fpr, then flow test my injectors at that exact psi and duty cycle, to give me a relatively accurate idea of how much fuel it's going through so i can do a rough calculation of the bsfc. but that's a lot of trouble for not a lot of benefit. if i had an engine dyno and a couple weeks to play with, i could get all sorts of data.
i was going to use renny rotors and go for big fuel economy, but i realised that 8.5 rotors will save money. with the 8.5 rotors, i'm aiming at 400whp on 87 octane + water/meth just to see if i can do it, but i should have absolutely no problems running it at 10-12 psi on a daily basis...even without the injection. so $.20/gallon is going to save me more money on fuel than the 1/2-1mpg increase from the high-comp rotors.
back to the topic-- not sure what it's going to do for split and economy, but the motor that's in there was intended to be a temporary solution so i could drive the thing. the new motor makes factory compression. that should make quite a bit of difference, even with the lower compression ratio.
if i get a bunch of extra time and money, i'll set the cruise control on the dyno and i can play around with how lean lean i can get it and at what point it loses its benefits. but in order to do that really well, i'd take the vac line off the fpr, then flow test my injectors at that exact psi and duty cycle, to give me a relatively accurate idea of how much fuel it's going through so i can do a rough calculation of the bsfc. but that's a lot of trouble for not a lot of benefit. if i had an engine dyno and a couple weeks to play with, i could get all sorts of data.
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