Hell all

I am fighting a problem I cant seem to find for the last few weeks. The car will run like 7.42 to 7.43 in the mid afternoon and then around 3rd round of eliminations it will fall off to a 7.46 out of no where. I though it was converter or trans related but I have changed both and still the problem is there. I found my ignition box the lord mounts where broken and one coil lord mounts was broken also. No wires where broken but the box was flopping around in the car. I don’t know if that would do anything but we will see this weekend. I cant feel the car spin or anything. On the slow passes the car will fall off 1.5 or so mph over the other runs (It is also slow right from the start not just down track). Usually if I make it thru that round the car will be back to the same number. Unfortunately this weekend I made it past one round and the next it ran another 7.46 the next pass.

Any thought would be appreciated.

track is going away.probally will pick back up if you can hang on long enough

I dont think that is it. This is somthing new that has just popped up in the last few weeks. I can see it moving by .01 maybe .02 on the outside but moving from a 7.428 to a 7.46 is unacceptable.

what made say that was it is like that at one of the tracks we run on.they switched to a lessor compound.

skip a few #4s with cheese....lol

I chased a similar problem last year,turned out to be a broken wire at the alternator positive stud.I checked a LOT of things,and it wasn't till i talked to APD and Randy said..."is it charging ok"? Immediately I said yes because I had no battery problems,but when i looked at the alternator..there it was!
May not be your problem,but worth a look.
Good luck,Grant

quote:

It is also slow right from the start not just down track

Could the side walls be starting to show some breakdown, how many runs?

Bob, have you checked rear calipers and brake hoses? Spin the pinion by hand and feel what the bearings feel like ect?

Not sure what time of the day/night you run eleminations, but 3rd/4th round is about the time the dew sets in around here. That would explain why you're slowing down. It might not be enough for you to feel the spin and the extra moisture in the air would slow you down also.

We typically make tt at around 10am to 1pm. Then eliminations start around 2pm. When I have the problem it is around 4pm or so.

Brake are definatly not hanging up. I have had that happen before and I looked at that.

The tires might be a problem so I am changing them this week. I will check the alternator.

Thanks for the replys

Bob, are you seeing the car slow out of the beams or just the ET at the top end?

I will add that the wire was touching
intermittently and causing weird et's...2 or 3 consistent ones ,then one .03-.04 higher.
Grant

Bob

What kind of ignition do you have?

I had the same exact problem you decribe. It was my ignition box, MSD Digital 7. Not sure what the issue was w/the box but I would either loose or gain about .05 and 1.5 to 2 mph out of the blue. Some say the box is on it's way out and not putting the power out and others say the timing isn't the same. Either way, I changed the box and no more issues. It was the original 7530 and MSD don't service it,, nice!

Bob, Do you think you might be to rich on the alky??? Around 4 pm is in the heat of the day, and the track gets worse, to rich will slow the car down that much and lose that MHP, it will in my dragster. I agree with RUSTY Maybe the track is not preping the track like they use to??? Trying a different type of VHT. Maybe track cutting expenses?? LOL Could be anything.
But I would check the the fuel system myself.
Let us know what you find
Brian

Later If I get a chance I will post my log book. But the track was killer last week. It had nothing to do with track prep. I talked with some other people that run really close to my ET and they where running right on. If anything I might be a tad on the lean side. I am running a Digital 7 box 7530T to be exact. Again the car was slow all the way down the track. Going from memory, on the first few passes my 60’ was around 1.066 to 1.069. On the bad runs it fell off to 1.078 to 1.08 and then was off by .02 at the 330 and 1/8th then off by .04 by the ¼ and down 1mph.

Bob, If you are on the Lean side, when the air gets better, wouldnt you slow down??? When the air gets worse, wouldnt you run quicker?? Am I right in the way i am thinking????? That is how it works for me.
I dont think its the conv. A bad conv would slow you down alot more than .04.
Im still leaning toward the fuel. JMO and $.02 lol Whick will not even buy you a soda LOL
Good luck Bob
PS> How is that leg doing anyway???? Hope its better now. Havent heard anything in a while.
Good Luck
Brian
Bob, dial a 7.50. At least you will know you can get there. Just drive the top end really well and its all yours LOL good luck

I had a problem similar to yours, but it was more random in nature. It ended up being the starting line enhancer was not opening the throttle all the way for an extra split second off the line on some runs. The 60' would be off .02-.04 and the mph would be down. I changed the pneumatic cylinder and everything has been fine since.

Mullis 565 I would have never thought of something like that. Do you think a little oil in the air line once in a while could help??? Thanks for the info.
Brian

That could be I do have an older SLE. I will check that.

Brian my foot is doing better. I have taken the hand brake out of the car and am back using my foot again.

bob you have a pm.if i did it right