Last time out we turned on the spray for the first time,(125HP plate) made a few easy 1/8 passes then set the controller to 60% over 1.5 secs and made a full pass and pulled a 9.8x @ 138.0mph...I was out of gear at 1000ft and lifted. Since the engines purpose was for the hose, I opted to lower the gear ratio to allow a full 1/4 mile pass....out came the center and scott at drivelinesolutions.com dropped a new 3.89 motive gear in with a strange spool.
Off the trailer this morning I made 1 motor pass to judge the track surface and compare the new gear to the cars previous motor times....SAME!
The 60 was not any worse than with the 4.30`s the 1/8 et was nearly identical BUT, 1/8 MPH was up 7mph! 1/4 mph and et were pretty much the same as they were before?
I decide to run the same program as the 9.80 run on the next pass, with everything set just as it was on that previous best except the track and the gearing. This netted some mixed results, 60 time was down for some reason a 1.57 instead of the usual 1.4X ....1/8 et down by .200 but, mph at the 1/8 up by 4mph over the best run, 1/4 mile time was off by a 10th (9.91) BUT, I was able to make a full pass now instead of running out of gear...MPH of 142.26
In defense of the times, the track is not the best around, bumps and I usually need alot of wheel input to keep it down the middle, actually I had to abort 2 passes due to fish tailing.
The Spool is the meow though, I can do a nice slow starting burn out and heat ALL of the tire now, before with the true trac I had to stun with a full throttle hit to make sure both hides would be heated, no negatives with the spool as far as I can tell

I was sure being able to keep the loud pedal on the floor all the way would have netted me a few more tenths, but no. the engine is just at 7,000 at the stripe, just past peak HP..

maybe it`s the track, I`ll have to get it to the "better" track next week or so.

 

Car looks good and judging the mph it liked the gear swap and with a good track I think you have a .60 or even a 9.50 pass with that tune up.

 

it's hard to tell you know? like you know very well that et is heavily affected by 60' times. and if you were fish tailing on two passes, than i'd be willing to bet that it's spinning! just a thought...