Hot weather tune up?

[A/Fuel]

Two weekends ago in Martin, Michigan we had 94% and legal weight for the NHRA, it ran low 40's. We took it to Brainerd last weekend and it ran a .39 first pass. Tried to give it more timing eariler, and it slowed. It was making more power and slipping the clutch at every move we made. We added more weight and tried to balance the timing. Apperently we were behind on the weight. When it ran the .39 it broke a intake lifter at the hit, so it was down a little on power. On the second run it broke an adjuster 4.7 seconds into the run, but by then the engine was so far ahead of the clutch it allowed the engine to drop a few rpm to let the clutch start to grab. It was still running 265 mph!
Just standing on the starting line watching the clutch dust was the first clue, then leaning over the car at the shut down area and feeling the heat coming off of the back of the car was the second. It burned through my gloves and the disks were all blistered and showed signs that they were trying to weld togather. We even lowered the back wing.
When it was hot out, our clutch was locking up before 3 seconds, and our rockwell was on the hard side, we had softer disks and more weight and it was still plowing through it.

[A/Fuel]

[QUOTE=TC;664315]What you are failing to realize is Nitro burns very slow and that is the reason they run so much advance, they need the lead time............

Also realize that once you drop a hole on a Nitro motor there is no relighting it, it's down for the count.......

QUOTE]

We had a very scary and expensive incident a few weeks ago that proves nitro exploads, that same car would also start to smoke the tires then drop a hole, stop spinning the tires and pick it right back up and take off.....kinda like instant traction control. lol

[dieselgeek]

Are you guys still running the wild timing programs, or have you tried narrowing down the crazy advance/retard plan to see if you gain consistency?

[A/Fuel]

On the .39 run it had 47 at the hit, .250 sec 49 .480 sec 53 .700 sec. 58, .880 sec 63. then 2 seconds in it was at 67.
The drive shaft at .500 sec was in the 1750 range, which on this car means it was ready to go up in smoke every time. I've only seen that car get away 1800+ a very few times, at a track thats so-so it will smoke the tires at 1500.

[TC]

Two weekends ago in Martin, Michigan we had 94% and legal weight for the NHRA, it ran low 40's. We took it to Brainerd last weekend and it ran a .39 first pass. Tried to give it more timing eariler, and it slowed. It was making more power and slipping the clutch at every move we made. We added more weight and tried to balance the timing. Apperently we were behind on the weight. When it ran the .39 it broke a intake lifter at the hit, so it was down a little on power. On the second run it broke an adjuster 4.7 seconds into the run, but by then the engine was so far ahead of the clutch it allowed the engine to drop a few rpm to let the clutch start to grab. It was still running 265 mph!
Just standing on the starting line watching the clutch dust was the first clue, then leaning over the car at the shut down area and feeling the heat coming off of the back of the car was the second. It burned through my gloves and the disks were all blistered and showed signs that they were trying to weld togather. We even lowered the back wing.
When it was hot out, our clutch was locking up before 3 seconds, and our rockwell was on the hard side, we had softer disks and more weight and it was still plowing through it.

What's your thoughts on that it had less power and went faster??...... Sounds like you guys have more than enough power, so I think your efforts need to be focused on the chassis and delivering the power to the ground.......

[A/Fuel]

The chassis worked fine, every move to put more power in by increasing the timing it just slipped the clutch more in that area. The engine would go up 200-300 rpm but the drive shaft would flat line like a step and the g-meter was showing the samething. Every lap we added more weight to the clutch but also added timing, it just seemed that we were a little behind on the weight compared to the timing.

[TC]

The chassis worked fine, every move to put more power in by increasing the timing it just slipped the clutch more in that area. The engine would go up 200-300 rpm but the drive shaft would flat line like a step and the g-meter was showing the samething. Every lap we added more weight to the clutch but also added timing, it just seemed that we were a little behind on the weight compared to the timing.

So your saying that maybe you should of went up in weight on the clutch and kept the timing the same?? Sounds like the way to go or at least give it a run to see what happens...... And how about a lesser percentage of Nitro??

[A/Fuel]

Well....30 grams makes a difference in one of these cars and we left that place with well over 100 grams than when we got there.
I was talking to Gene Snow before the last round of qualifying and he said his car was doing the samething and he was stacking weight too. I was running out of room for more, even using mallory. Droping the percentage would have just made it run out the back door slower here. The air was good and the track was even better.....or should I say cooler. I just came off tracks that were 150+ and the car I was on in Seattle was a turd. You go into a track deciding which side if you error is it going to be on. Then you hit a track thats 88-110 degrees....a 5.39 wasn't to bad that car, it slowed to a 5.45 in rd 3, but by 1st round of eliminations it ran a 5.41, it was 222 mph by the 1/8th mile and had a .950 60 ft. On the 5.39 run it had a .970 60ft and was at 218 mph in the 1/8th.
We ran a 5.41 and Chase beat us with a 5.47, so I didn't look at the computer much.....I just packed up and left.

It also started out with 75 rockwell disks and I was at the lowest we had on the trailer by rd 1. 68.

[dieselgeek]

Scott, can you PM me a phone numer to reach you? just spent a few minutes with Gene and he shared some advice that might be helpful on ignition tuning for nhra a/fulers.

[A/Fuel]

I just did.
A few days ago we took our mags to the MSD trailer to see what the internal phasing was, one of them just needed a new shaft and the other one needed to be shipped back because one of the screws were stripped and they couldn't take it appart at the track. They couldn't tell us anything until they get it appart. So we have one good one we know for sure now.