We are in the process of trying to freshen the Big Red Machine up for another season of record breaking ETs. After not being too pleased the previous year with the stock ford diff, we got a prototype Eaton diff from Eaton traction, to test out for the year. I still had quite a bit of differential issues last year, with it not holding the power and giving us a lot of one wheel peel. Well, we started pulling the diff apart for a freshen up last week. The Eaton uses carbon clutches with 400lb rate clutch springs. We pulled the packs out, and the carbon clutch material was just a melted mess of black goop. The steels had started to weld themselves to the other plates too. So we got a new clutch plate kit and fresh springs from Eaton. The engineer I was dealing with told us how we could modify the unit to increase the spring rating for more holding power. So we did the needed modification, then proceded to clean up the parts for reassenmbly. Upon inspection, we noticed that the side spider gears are all stress cracked. One more 1000 ftlb launch would have probably grenaded them. Time for more new parts.

Guess we are making some good power

 

Sal, did you ever get your traction problems corrected? When I saw your truck launch at WFC it seemed like you was having to launch then let off of it and then get back into the throttle again.

 

Maybe just maybe, one day I will make enough power to do that. I hope that day is soon. Goodluck at the track next year Sal. -Mat-

 

I sure hope we've got it solved. Last year I ran the same tire, rim, shock, and traction bar combo that JDM and JL ran, but could not get the same 60fts. We are 400lbs heavier and make about 200 more hp though, so that might be part of it. I made a few changes this year that I think will help. I checked the pinion angle and found it to be only -1, and with the leaf springs, even with traction bars, you still have a bit of axle twist, so on launch, I was definitely going positive. So I've got shims in there now that have changed it to -4. I'm also switching from that Hoosier radial 10.5 slick to a traditional bias ply Hoosier slick, 12.0 wide. Those changes plus the diff rebuild will hopefully solve the issue. With a 132mph trap speed, I could have easily hit the 10.0-10.2 range with sub 1.50 60fts.

 

Tweek it, tune it, Torque it!

Sounds like it's time for an Air-Locker. No clutches to burn up...

 

Go Sal Go, Go Sal Go

 

A little curious here Sal, but are you going to the "lightweight" 12.0/31.5-15 w/ C07 compound or the 32.0/12.0-15 w/ D05 compound? That will also raise your ratio since either tire will be 2 inces taller. And you are running 3.55's too, right? That is probably going to be geared just right for 135mph trap speeds, but that is just my opinion.

 

The tire I am using now is the same diameter as the radial was, so there should be no ratio change. The radial was a 30, but actual diameter is listed as 29.6. The new slick is a 29, but actual diameter is listed as 29.5, so all should be well.

 

Sweet Sal! Can't wait to see what ya got to show everyone this year.

-Mike

 

OK, I see what tire it is now. I was looking at Hoosier's website wondering what tire you were going to run. I overlooked that one you are going to run (#18190). I also see it is the softer D05 compound. With the softer compound and 2" wider patch (per tire), you shouldn't have any traction problems at all.

Good luck to you this year.

 

are you going to run modmax or crower cams as well?

 

What Sal calls 'freshening up'...I'd call 'Energizing the Warp Drive'

Go Sal Go

 

Sal
What fluid were you using last year and did you change it for this year. What do you think caused the clutches to turn to mush??
I have the same diff so I was just curious.
Dale

 

Let's see some 9 sec passes!

Just think, a few years ago, we could barely get into the 12's.

 

Sal,
The faster you go, the faster we all go

Sounds like you made some nice changes for this season,
Do I see 9's in your future
GO GET-UM BUDDY