This! Converter sounds hurt to me too.

Easy enough to check, I'll look at it.
Doug

I have a thought.
Walk up to the core support and pull up and push down. Can you physically move the front of the car? You should be able to do this if there is enough travel in the shocks.
I had a similar issue on my car. My afco front shocks just stiffened up and quit responding to adjustments. They had always been flawless and you know how my car leaves.. One race I couldnt hit the tree and my 60s fell off. I fought it for several events. one day I grabbed the front of the car and tried to bounce it and I could not move the car.

I backed the top nut way off and could move the car. When I got home i pulled them off and put an old set of comp 3 ways on it at the tightest setting and it was night and day difference.
Now I have good shocks back on the car but that set bound up for some reason.

Its easy to check and eliminate as an issue.

Doug, You said in your original post that you won the race...congrats! What were the ET's on the passes that were all stable after the 60'? If the ET and MPH increments are close, then a comment earlier about where you are tripping the beams (60') sounds very logical. I never had an issue with wheelies, so I'm a rookie there, but makes sense. We run Eddy 750's on an original intake in "FRUSTRATION". I also have an original set of Carter 750's (not MW). The Eddy's from new were nearly impossible to adjust the idle. Found out the throttle shafts on both carbs were really loose. Had to have them bushed. It ultimately got so bad that the car would idle at 2-2500 after a pass. Good luck.

No idea why the photo was posted upside down. Name of the car fits!

I had problems with mine only at launch and found out it was something in the tach screwing up the msd.

Just talked to Perfect Converter. Converter is undamaged and has a mechanical diode along with a steel stator. Good parts. So it'll get a couple toringtons and back together. I should've been clearer in my time slip comparison. The incremental splits match up . The actual ET is slow by at least what the 60 fell off . Example, last week 1.32/9.09, 1.40/9.17. Shocks will get pulled and dynoed.
Doug

Makes sense. You did say you put new slicks on the car. Were they the same brand and compound that you've run in the past? I've seen 60' times go away when the slicks stop doing their job. A car as fast and violent as your's will likely eat up sidewalls pretty quickly. Sometimes it's good to have a slow race car...like me; ) Still plenty of problems, but certainly cheaper to fix. Good luck. When is your next race?

I'm not a fan of mechanical diode had one go bad you could see on racepak, when it went bad, 60' was all over the place. Sent the converter back they said it's OK. Ask them to change the stall by 300 hundred looser Long story short I didn't put that converter back in for a few years then went to a bracket final in Boise and thought I'll give it a try should work great for higher altitude. It did on the 1st pass then broke on the second pass would want to push me while staging but it was done lost 7-9 mph and ET went to crap. Sent it back again this time they changed the diode and I sold that convertor and will never use them again. I will only run spragless nothing to go wrong but the normal laying over fins.
You don't have racepak or any data recorder on your car?

Tires were swapped at the end of the years when I started noticing the problem. Since this issue has occurred the video shows zero tire slip. Also has done it now with 2 different brand converters. it will be getting a data logger.
Doug

Don’t discount this. It has happened to me also. My car was EFI. The logger was the EFI. When this happened, it would get a corrupt the log, so finding the issue was difficult. The engine wouldn’t die, nothing went 100% dead, but everything electrical would glitch. Would not believe it if it hadn’t happened to me.

I know that some NSS rules say no data loggers, But honestly I would hide it in the car if I had to. At the minimum get yourself a Racepak Sportsman. Best thing you will ever do, and your fast car will become even faster ! ! I couldn't race without one now LOL

I had a friend with a backfire problem on a nitrous mustang. It would backfire at the hit no matter what we did. The problem ended up being a bad connection at the master switch. We found the problem real quick at the first night race because the taillights flashed, then it backfired and moved out. We fixed the connection and he promptly dang near drug the bumper off of it on the next pass when everything worked as it should.

Here's my plan. Pull the shocks and run them over to my shock guy. He has dyno sheets. We'll see if they match up. New 16volt battery and upgrade alternator to 16v. Going to swap my buddy's intake top and pro systems 950 carbs before track testing. Pull the lower intake to inspect gaskets. This would be a time consuming swap at the track. Parts I will bring; a bolt on bypass for the master switch, spare coil, spare MSD box, spare crank pick up, new can of fuel. Will be purchasing a data logger. It will have to be removable for NMCA. That's just going to take a little longer than my current 3 week window before our next race.
Doug

Jess echoes my sentiments on mechanical diode converters. Been there done that. As for converter guys saying they found nothing been there done that more than once as well. not saying that's happening but seen it happen more than once. Just had a buddy wipe out the thrust in his S/ST car due to a converter(big name shop), but they told him all was well. Oddle enough came back with a billet fro Kinda like finding a problem with and MSD unit that wont start a car yet they find nothing and works like a champ when it comes back

Plenty of validity to the cut off switch deal, seen that happen a number of times. Especially on older switches or hard leaving cars. Charging system voltage issue in general on the same style car. We had an alternator issue on the dragster that was causing the car to shut off when the shifter was activated. Car was still deadly consistent but we could not figure it out. Til it was on a single and we heard it shut off. The alternator was working just not enough to cover up the draw of the solenoid. If we had a date logger would have been much easier to diagnose. New battery and alternator and it was good to go.

Like I say be interested to see what you ultimately find.

First thing I would swap would be the MSD box.
One of our cars back in the day lost a tenth over time, car was running low tens. Forgot what led us to it but replacing the box brought it to life.

Two converters - same result, eliminates that I think.

Had a bad digital 6 box years ago that slowed my car down 1/2 second, but not on every pass. Maybe once every three or four passes.
Set up to run 10 flat, would run 10.50ish when it occurred.
Chased everything most of a season before swapping the box out and finally fixing it.
Good thought, could well be the box.. capable of wierd issues

Converter #1 has the diode. Dont know about #2 . It is an ATI unit. Not inconcievable that 2 converters could be randomly bad. But I think it would be unlikely. Converter #1 has been really good for 3 years
We'll see soon.

Doug

Having chased the same dog, and frankly, still waiting to see if I know the reason, and actually holding a diode in hand, they either work or destroy themselves. Mine wore over 15 years, but still worked. I’m trying to get back together, to verify a fuel delivery suction issue. Good luck!

Would be interesting to see how they checked the stator overrunning clutch. Checking it by hand could allow a bad unit to pass inspection. Unless you apply enough torque it’s conceivable that you could have a stator cam that’s lost it’s spline lock.

I have seen that in diesel converters, they will pass the “finger test” we spoke of but will fail the bench test. We are talking hundreds of pounds to test the unit on the bench.