Gentleman and Ladies if any...

I have been fighting a very strange problem with the car. It will run 120MPH a few runs and then 116MPH. At either MPH it is stupid consistent but does pickup ET when it runs the higher MPH.

Only place it shows in graphs is Engine RPM, driveshafts overlay perfect.

graphs. Top Engine RPM, middle trans pressure, and bottom is driveshaft. Pressure are all within 4-7psi - carb, oil, engine temps and trans temp all within 3-8 degrees.
https://photos.app.goo.gl/CdJWrKEmWYnSMHms6

logbook
https://photos.app.goo.gl/hFqMp7irc8bv7pLB6

final run at 120mph
https://photos.app.goo.gl/e4QdBF54EtBXuWnp9

I put a new grid in it last year, zero difference and went to the finals of a race. I have changed carbs, on alky with mechanical pump, FP all good. AFR looks about the same. brakes are TBM and are not excessively hot after a run vs 120mph.

I ordered a new crank trigger and harness that I will install this week, along with new coil.. The wires and plugs have also been changed. Distributor, rotor, converter was even swapped last year. Third member broke two weekends ago so that is all new and fresh with 9.5Ford. Axle bearings were checked when out and felt good.

It is acting like the timing is retarded or advancing - with timing light its rock steady at 34*. I cleared out the grid memory card. I went thru every table in grid and there are no retards setup. Just the basic stuff. Weather is not a factor either I have Ifamily system and the runs were within 1hour.

Lastly I went thru car and removed every ground wire, cleaned, and put star washers, sprayed them with protector after they were tightened. Did that last year and again this past week after it did this at 5k weekend race in the semis to me.

Does it with BOX and NO Box alike. Same lane and several different tracks

Looking for ideas.

This message has been edited. Last edited by: ski_dwn_it,

line lock ???

It's also odd to me that engine rpm is up through the whole run but the 60 and 330 is still the same.

Could brake pads be binding in the calipers or loose tie rods and alignment is changing at times and making tires scrub I mean you’ve changed everything or at least sounds like you’re monitoring everything you can

Got a sprag or diode in the converter?

I thought converter at first but he said he tried a different one

Converter was changed.

Inspected cap and rotor that was changed last year too. Nothing.

Alignment... Didn't check that but car drives like it's on rails.

Brakes, I've put hand on rim and it's warm but not excessive. I'll pay more attention to that next time but car coasts really easy.

Line lock only active when I do burnout. Last year checked that too.

Car moves in burnout as soon as I let off it.

Appreciate the ideas.

Checked grounds to battery all good. Checked voltage drop. Called KR on the throttle enhancer and they told me how to check that. Can't even begin to pull it apart

quote:

Sportsman

Rear wilwood brake calipers stayed slightly engaged on mine. Car slowed about that. Could not find issue till I jacked up rear for something else and could barely turn them with a lot of force. Good luck