Good for you. I still believe that the intended use is important as well as weather conditions and type of gas used. Most drag racers tend to run leaner cars than most road racers. It is not a whole lot leaner, but still leaner nevertehless. A 20 min session on a lean engine on a road course at WOT is more likely to do damage to your engine than a 11-13 sec run down the 1/4 mile. From the AFRs that I have seen, Drag raced cars have AFRs in the high 11s while road raced cars have AFRs in the low 11s.

 

Bringing this back up with some track results. I hadn't touched the car in a month or so, but decided to hit the drag strip this past Friday. On the way to the track, I did a 4th gear *only* pull from ~2000 RPM and logged the following (a bit on the fat side from ~5000 RPM up):

RPM Boost (KPA) AFR
5498 235 11.00
6028 231 10.63
6518 229 10.76
6802 228 10.78

Got to the track, didn't touch anything, and logged the following for 4th gear during a drag pass:

RPM Boost (KPA) AFR
5506 242 10.00
6012 238 10.00
6535 236 10.00
6808 235 10.06

By the time I pulled enough fuel out to get the car to run closer to 11:1 in 4th gear at the drag strip, it ended up being closer to 12:1 on the street.

So, assuming this is normal behavior, what are you guys doing about it? Running 12.5 AFRs on the street in order to run 11.5 AFRs in 4th gear at the strip? Running multiple maps? Running extra fat at the strip?

Or is this much fluctuation *not* normal?

 

What variables changed between your street log and your track log? Did you up the boost for the track? Did temps change? Pressure?

 

Jack, I am curious if the difference is enough to bump you from one load % to the next one up. I realise we are talking 7kpa, but between that and how the ECU is determining load, may that be enough? How much (if any) difference is there between load cells at lets say 6500? I havent logged anywhere near that dramatic amount of richening up in my IX MR. It seems fairly constant and if anything tends to lean by the time I am in 5th. 1-4 are all fairly close if I recall correctly. I will go look at my most recent log (though it might be contaminated data cause I have 110 in the tank) and see what happened for sure.

 

Kilopascals are listed, that is an ignorant question.

 

I highly doubt load cell changes, but believe in the likelyhood that it is at least partly accelleration enrichment based as you pump the TPS during a drag race pass. Personally I would tune for a drag pass if that is what you are trying to accomplish.

 

That was going to be my next question actually, what do the accel enrichment tables look like?

 

Please refrain from commenting on my posts. I do not like you and you do not like me. So please quit replying to what I post. Don't you have something else to do than harrass me everytime I post?

 

Read the thread and posts prior to posting. Problem solved.

 

Drive the same on the street as you do at the track

Downshift to keep the rpms up and engine load low, instead of passing in fourth, go to third. My car is tuned for 11.5 at the track, and I have no trouble on the road.

 

There is no where near that much difference in my fuel map between neighboring cells based on my (albeit still limited) experience. I'll try to add some screen shots of the fuel map when I have the laptop hooked up later.

I have not touched the Accel Enrichment tables. They are at 1.43 from 4000 RPM up.

I am more concerned with single-gear vs multiple-gear pulls. That is, in your MR, compare a 3rd gear-only pull on the street vs 3rd gear data from a 1st through 4th/5th gear pull at the track and see how much variance there is.


I will try and get more useful data for comparison purposes. Unfortunately, that night at the track, I was having some issues with EvoScan and didn't get any useable logs. All my recent logs are from 4th gear only pulls and I don't have any logs from multiple-gear pulls to compare. I'll try to head back out to the drag strip on Wednesday or Friday and get some more info.

 

You don't have anything to log boost vs AFR vs RPM, do you? I'd be curious to see info from a 3rd gear-only pull vs 3rd gear during a drag pass.

On the street, it doesn't matter if I am in 3rd or 4th - AFR is pretty consistent. It's when I am pulling multiple gears that I end up with the inconsistent AFR. See this post. Basically, to get my "strip tune" right, I was too lean (for my taste) on the street.

 

I made an honest mistake, but the way you responded is indicative of dislike to me. You do this in almost every thread I post in. Please stop. Do not reply to my posts.

 

This is PM material. Stop cluttering up an otherwise technical thread.

 

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