What the hell is going on

[terry5357]

Lately I have seemed to have lost .3 at the 1/8 mile track. the reason this thread is here is I don't why, I haven't changed anything lately (last 3 or 4 months).
A little history. I installed headers last November, and started using an O/R "X" pipe. I am wondering if my O2 sensors may have something to do with this loss of performance. I have only run leaded race gas just a very few times and that was to see if advancing my timing would help dropping my et's.

When I was changing my headers I had a friend of mine helping and mentioned how white my O2 sensors where. Could this be the culprit. I don't want to just start throwing money at the problem by just replacing this or that. Anybody have any trouble shooting ideas.

 

[rojizostang]

a couple of guys around here always re-load their tunes before going to the track. they say the same thing happens with theirs, don't remember who it is, but the consensus was it had to do with the computer adapting to the the owner's driving style over a period of time, fwiw

it seems re-loading the tune eliminated this anomaly, iirc

 

[terry5357]

a couple of guys around here always re-load their tunes before going to the track. they say the same thing happens with theirs, don't remember who it is, but the consensus was it had to do with the computer adapting to the the owner's driving style over a period of time, fwiw

it seems re-loading the tune eliminated this anomaly, iirc

I always reflash at the track.
I did a search on the O2's and came across another thing that might be the culprit. since it is summer time and you never know what the gas companies are putting in the gas theses days. From my search I see that during the summer more ethynol and during the winter there is less. Going to throw some high octane unleaded in the car the next time I go to the track and see if that helps.

 

[rojizostang]

how much different is the temperature and humidity from your normal times to the losses you speak about. certainly a significant amount is expected just due to summer time conditions, no?

 

[matt texass]

It's hot. Different DA.

 

[terry5357]

how much different is the temperature and humidity from your normal times to the losses you speak about. certainly a significant amount is expected just due to summer time conditions, no?

It's hot. Different DA.

not first rodeo...........lol

It was about the same DA this past week end as it was the I was running the quicker times. around 3100 according to Don's DA calculater.

85-90 degrees
29.89
dew point 68 degrees


this is what is leading to believe that its gas or O2's. But still looking to see if you guys may have some other ideas

 

[GAP]

Are your trap speeds the same?

 

[ski]

Also, was your 60' time higher during the slower run?

 

[silverstang07]

why are you running race gas if I might ask?? Also I would suggest to stay the hell away from leaded race gas................

If you could post up two different time slips (one before the issue, one after) it could possibly make it easier to see what is going on.

 

[chad05gt]

It takes more nrg to ignite a more stable fuel... low compression and n/a dont need...

 

[jroc07gt]

sorry tp thread jack but is it really a good idea to reload your tune when you go to the track?

 

[Gene K]

terry5357 - Has it lost both ET and MPH? If you have been turning it pretty high the valvesprings may have given up. Try short shifting and see if it gets quicker.
Are the 60's falling off despite full traction? Maybe the clutch giving up. Put it in third, bring it to 4000 rpm and smoothly let out the clutch. Dont drop it but dont slip it. Just come out smoothly. Should stall it pretty much instantly.

jroc07gt - I usually reload mine if its running slower than normal. The "adaptive learning" can sometimes decide to mess with the AFR or Timing because of something its experienced in the recent past.

 

[jroc07gt]

well usually i reload the tune before i leave the house for the track so its maybe 45 miles fresh but this last time i drove over a week on it and didnt reload it before the track. i was cutting 2.0 60's and the rest of the run was clean but i was about .2-3. thenths slower. i also noticed right off the back that i was trapping about 2.5 mph less. the weather was pretty much the same ass like weekend.

 

[terry5357]

Gene......Normally my 60' is 1.92 (auto no stall converter) I normally run 8.15-8.25 @ 86 mph, now runing mid to low 8.40's. I am not a high rpm guy since the car does not make any power over 6k so there is no snse in going there.

I don't run race gas all the time. I have run maybe a hand full of times and that was just experimenting with increasing timing, even if I did run leaded I don't think it would be an issuesince I have no cats

My next step is to rent/buy compression gauge and see if it just may be time to start considering a little freshening up........

 

[Hawgman]

Gene......Normally my 60' is 1.92 (auto no stall converter) I normally run 8.15-8.25 @ 86 mph, now runing mid to low 8.40's. ........

I think your time is a little off. Todd and I both could have sworn we saw you running running 8.6s Friday night. Also, I think the DA was closer to the north side of 3500 than it was "around 3100". I checked it right before I went out there and it was 94 degrees still, and the humidity was ungawdly ( 90% + before that front blew in). I know it was killing my times. Best I could run all night was a 7.5. I finally got disgusted with the weather after the front blew in and we were running in to a friggin 20mph head wind and I called it a night and just watched the 275 DR finals instead

 

[psfracer]

The DA effects NA cars alot, and if that was what the conditions were (that Hawg described) that would kill you times. The humidity is the killer.

 

[terry5357]

I think your time is a little off. Todd and I both could have sworn we saw you running running 8.6s Friday night. Also, I think the DA was closer to the north side of 3500 than it was "around 3100". I checked it right before I went out there and it was 94 degrees still, and the humidity was ungawdly ( 90% + before that front blew in). I know it was killing my times. Best I could run all night was a 7.5. I finally got disgusted with the weather after the front blew in and we were running in to a friggin 20mph head wind and I called it a night and just watched the 275 DR finals instead

Friday night was not when i was talking about Friday night you could have cut the humidity with a knife. Why didn't you stop and say hi. But you did see me run one 8.67, that was the last run I made after I had put my street tires back on (275/55/17's that killed my gearing) and had a set of slicks, generator, tool box and chairs in my trunk, and an ice chest in the backseat. THe time I was refering to was a couple of weeks ago when it was really nice, cool and dry. So Doc are you saying there is nothing wrong with my car. I think the last time you saw it run (when mikebluevista was there) I was runinng 8.20's but as I remember it was pretty cool.

 

[Hawgman]

"pretty cool"? It was friggin 40 degrees!

The only thing wrong with your car (in my opinion) is it is summer in Texas.
Actually I did say hello to you once as you were walking by and you never looked. I said hi to you once as I drove past you and you didn't acknowledge. I was parked right across from where you parked and when you backed in (which was kinda funny to watch because you musta stabbed at it 5 times) and and got out Todd and I both were leaning against the back of Todds car and said hey.. no response. So I figured fukkem..

BTW, what the hell was that you were running for rear tires? Think they could stick out a little bit more?

 

[terry5357]

THey are what I can afford at this time, beats the shit out of street tires........unless you have something laying around you want to give me so my car would be more eye appealing to you........lol. And i apologize for not respnding, I would have though the same thing......again I apologize.

 

[Hawgman]

No really... what was that on the back. You said "I had a set of slicks" but what size were they, what wheels, etc? I don't have a set of track tires and wheels laying around that are spares, but I do have a pair of 17X8s that I am not doing anything with.