I tuned my A/F via wideband for high 11's in boost. It holds taht A/F ratio just fine at WOT and gonig into boost. at crusing and idle, it is a steady 13.5-15 depending the conditions. I tuned that crusing A/F in 3rd gear. But what I noticed when iw as on the highway was that when I am crusing in 5th egar at say 3000-4000RPM, it rusn very lean, in the 17's. I even saw it hit 18 once. So wth, I put it into 4th egar, held the same speed, and it was also running lean, when I accelerate slightly, obviosuly it starts to richen up, but what I was wodnering was, how come it's so much leaner in the higher gears then the lower gears at the same RPM? Is it jsut the fact that at that speed, there is much more air flow? So I figured, but then if I added more fuel while crusing in 5th stog et a steady 15.0, all my lweor gears were running queit rich at crusing in town because of this.

 

this is a known problems for some/many EMS's. which one are you using? uberdata recently added code to compensate for higher gears, and maybe someone can chime in about hondata and the others as they might have this option as well.

 

I acutally just have the ghetto afc hack along with a ECU chip I had made to compensate for the timnig correction and to provide boost retard. I COUDL richen it up mroe so it's like in the 15's in 5th.. but then all my lower gears run at like 13 crusing. blah I get better gas mileage in boost. lol

 

TTT

 

The stock Honda ECU actually has gear-dependent fuel enrichment. As keebler said, Uberdata allows you to modify the enrichment if you'd like. There's nothing you can really do with what you've got, though.

 

depens on alot of stuff....what size injector...what psi....if you have small injectors them might be maxed out and not be pushing enough fuel for the amout of air goin in....also if you are running high boost the stock map sensor wont read it...youll need a 3 bar and this would resuly in you needing an aem box...fmu's are only good to a certain point...let me know your setup and ill be able to help

 

Monitor your egts if it not getting crazy hot then let it be.

 

As posted in my first post. I am only asking about crusing A/F ratios

 

yeah it's always about 1000F or less.

 

TTT

 

its not running leaner due to higher gears, you're most likely in a different load site even though you are at the same rpms...

 

Hrm yeah that makes sense. but even for a standalone system ofa DIY system, how would you fix this? cause If I add fuel so that it's nice and stoich at crusuing. it becoems overly rich in a lwoer gear because there is elss load that that RPM in taht gear.. I might jsut havet o sacrifce it and tune it for 4th gear crusing and suffer running a bit rich int he city.. What's the leanest I can have it running at when crusing and still be somewhat "safe"?

 

I ran into the same problems working on a friend's S13. During near-gauge atmospheric pressure at steady acceleration up hills, the motor would lean out up to between 16.0:1 to 17.0:1 AFR's.

There was nothing I could do about it working with only an A'pexi AFC, so I had to run the settings closer to 14.0:1 at lower TPS inputs to keep things reasonable. It still does it a bit, so I'm wondering if an E-manage (w/ support tool) would be a better solution for his car so I can adjust fuel correction according to TPS vs. rpm instead of just as a function of rpm.

On a Honda, I don't see why you couldn't compensate for it just by working on the load columns so that they all produce the same AFR. I'm able to do this on a loading dyno with reproduceable results.

 

Anyone know what version of uberdata fixes that? I don't have a wideband, so I don't know if it's lean at different load points.

 

m R g S r, It's a script you can add to 1.66. I think it's also in 1.70, though.

As I stated above, the ECU has a routine that determines what gear you're in and applies a fuel multiplier. It doesn't matter where you are in the map. You can be in the exact same spot in each of the 5 gears and get a different a/f. It's not a huge difference but it's there.

 

Well I didn't tune my car, Jeff Evans did back on sept 2nd. And I think he used the newest version of uberdata then. .

 

Ah makes sense of the fuel multiplier.. but as for not being that much of a diff... 15% throttle in 3rd at 3000 is about 14.7 exactly... 15% throttle in 5th at 3000 is at 17+ Sometimes hits 18. To me. that's a huge difference even if it's not much load.

 

even tho i do not have a turbo yet i ran in to that same problem with my motor with high gears with the stock ecu.. i did not know it was leanig out till i blow the head off of it. one lesson learned! well i bent 4 valves and i was lucky i had a spare head setting around that i could use.. after putting the hondata on there it told me every thing.. it was leaning out after 6000rpm and went down hill from there... if it is leaning out get some type of ems for the car it will save it the motor
good luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tchleung &raquo;</TD></TR><TR><TD CLASS="quote">Ah makes sense of the fuel multiplier.. but as for not being that much of a diff... 15% throttle in 3rd at 3000 is about 14.7 exactly... 15% throttle in 5th at 3000 is at 17+ Sometimes hits 18. To me. that's a huge difference even if it's not much load.</TD></TR></TABLE>

Well, all the more reason to run an EMS that can correct it... such as Uberdata