Need ideas where too start looking for a problem in the weekend bracket race.
4 passed Saturday, 9.75 to 9.78.
2 Time trials Sunday, both 9.74.
First round dial 9.74, run 9.82, but speed exactly the same, 139 and change. Other guy redlit.
Don't know what to think, dial 9.79, split the difference. Run 9.90, speed exactly the same.
Same pressure in slicks, same burnout.
Was really hot and humid, but had been as bad or worse on Saturday.
Playback tach showed nothing different than usual.
Have FTI built 8" converter, spragless.
Opinions on where I should start looking.
Sorry for the long post.

Where on the track did it lose the ET? Compare your time slips and see where it slowed down. What were the 60' numbers?

post the split times. that will help point you in the right direction. also what were the weather numbers from each run. post up the real info and let us take a look see

Slowed down all the way down the track:
Normal numbers 1.36 60' 6.18 1/8th 9.74 1/4 139.xx
First slow pass 1.39 60' 6.24 1/8th 9.82 1/4 139.xx
Last Pass 1.40 60' 6.30 1/8th 9.90 1/4 139.xx
Seems like it was probably spinning but couldn't
feel anything and nothing showed on the playback tach.

Same MPH generally = same HP.
I'm gonna say look at Trans or Converter?

quote:

Originally posted by FootbrakeJim:
I'm gonna say look at Trans or Converter?

x2.

From run 1 to 2, you could argue it just spun. But from run 2 to 3, you only lost .01 in 60' but another .06 to 330.

With the 60 also being way off, I'd be thinking converter first of all.

I would think trans/converter first.

Beyond that, oil filters are cheap, cut it open and inspect.

post 330's / 1000's too, do the split times so you can exactly at what point all the et is gone. I bet that will help point where the issue is. when does your car shift?

Normal Pass 1.36 3.97 6.18 1000 timer not working
ET 9.74
First slow pass 1.39 4.02 6.24 1000 timer not working ET 9.82
Last Pass 1.40 4.05 6.30 1000 timer not working
ET9.90
Least loss is in top end half. Most in first 1/8th. Bad day for the 1000' timer not to work.

Your loss is pretty equal all the way down the track.

You lost .04 in the 60' and then an additional .04 between every set of cones that you have numbers for.

I'd suspect you were just down on power, but your MPH being exactly the same doesn't add up with that.

when does it shift time wise, what fuel do you use and what did the weather do all day from first pass to last pass. Also, do you have anyone you can compare to similar setups to see what their car was doing.

also what is your warmup procedure, so we can see if we can trust the first pass or not. you keep stating "normal pass" id rather see all the slips and see the progression, I don't care what normal is, normal for one day is not normal for another. So both time runs are 9.74's then 9.82, then 9.90. your split time difference was .08 from 60' to 660' which is concerning unless you are way off on tuneup and those runs were 10 hours apart, we need more details I think, but I think trans is probably some of it.

Those four passes were each one hour apart. The four the day before in identical weather conditions were all within 3 numbers of what I listed as normal pass. The car has been running the same numbers for five years, only varying slightly with the temperature and dew point. never any slowdown like this. Something definitely changed, maybe just track conditions, but this kind of variation is a first.

Voltage ok? Ignition...

Our slower car with a TH350 could lose a full tenth on a pass, never felt a darn thing, and the MPH was the same. Tried different converter, same thing. Even changed the engine combo, same thing. The mystery tenth.......

So I'll bet you a hamburger you have a trans problem. Seeing that you are spragless, I doubt the converter is an issue.

My car did this once about 10 years ago. It cracked a couple cylinders and was ingesting water. I picked up on the car running 9.84/9.86 as opposed to 9.76 in very similar weather conditions, but with the same MPH oddly. Not saying your engine is blown, but there could be something wonky going on inside.

Might be a dumb question but did anything change with your staging? maybe bumped in further?

Very easy to spin .03 in 60 feet, then lose more ET at each incremental and run the same MPH.
In your signature it says "best et 9.43", Im guessing that was in mine shaft air? Even if thats true, thats quite a swing in ET to me?
Is this your first time out this year, is this a new convertor, have you changed anything else? With MPH being the same I would have to assume its not motor, fuel or ignition issue. I would have to go with possibly trans, conv to tight, tires worn out or maybe suspension issue?

Have you checked timing?? Could be that simple

quote:

Originally posted by Sugar Shane:
Very easy to spin .03 in 60 feet, then lose more ET at each incremental and run the same MPH.
In your signature it says "best et 9.43", Im guessing that was in mine shaft air? Even if thats true, thats quite a swing in ET to me?
Is this your first time out this year, is this a new convertor, have you changed anything else? With MPH being the same I would have to assume its not motor, fuel or ignition issue. I would have to go with possibly trans, conv to tight, tires worn out or maybe suspension issue?

Yes, typically whatever you spun in the 60ft is double at the 1/4 and usually the MPH is about the same.

If you stage differently the difference in staging will affect the R/T and ET the same exact amount, yet the MPH will be the same.