Help With Correct Ratio!
Thread Starter
|
Senior User
Joined: Apr 2007
Posts: 375
Likes: 0
From: Glenwood, IA
Help With Correct Ratio!
My truck is a '76 F250. It has a 428CJ, C6, D60's, 4.10 gears, 205 t-case with 35x10.5x16 super swampers (SSR). I use this truck to run mud drags.
Now to my problem. I run in low range, the pits are 150' long. It is shifting into 2nd @ 60' and 3rd @ 130'. I know I need deeper gears but how deep? I dont want to go to far and hit top end too soon. I am thinking that around 100' I should be in 3rd? Maybe sooner? I am willing to take it to 6K RPM.
I do plan on changing tires to boggers which will help get a better bite off the line and in return I think it will put me farther ( maybe out of the pits ) when I hit 3rd.
Can anyone help??
Now to my problem. I run in low range, the pits are 150' long. It is shifting into 2nd @ 60' and 3rd @ 130'. I know I need deeper gears but how deep? I dont want to go to far and hit top end too soon. I am thinking that around 100' I should be in 3rd? Maybe sooner? I am willing to take it to 6K RPM.
I do plan on changing tires to boggers which will help get a better bite off the line and in return I think it will put me farther ( maybe out of the pits ) when I hit 3rd.
Can anyone help??
Post Fiend
Joined: Jul 2006
Posts: 6,948
Likes: 44
I am thinking more gear will take you the wrong direction. You will increase rpm but not have a big effect on tire speed. Maybe a 4.56 or 4.88 gear in high range would incresase tire speed, but the lower gear in low range might not net any better et's.
Thread Starter
|
Senior User
Joined: Apr 2007
Posts: 375
Likes: 0
From: Glenwood, IA
From what I see on other trucks is getting the wheel speed up fast.
On the other hand I have ran in high range before and it seems to have about the same results as far as time.
Every pit is different from week to week but I am running the 150' in 5.5 sec.
I think if I was to lower the gearing and run in high it would be fine in a soupy type mud. But in the heavyer clay type I would run into torque issues.
So if I can find the right lower gear for low range then it should work for high as well in the softer stuff.
I was thinking 4.88 or 5.13?
On the other hand I have ran in high range before and it seems to have about the same results as far as time.
Every pit is different from week to week but I am running the 150' in 5.5 sec.
I think if I was to lower the gearing and run in high it would be fine in a soupy type mud. But in the heavyer clay type I would run into torque issues.
So if I can find the right lower gear for low range then it should work for high as well in the softer stuff.
I was thinking 4.88 or 5.13?
Thread Starter
|
Senior User
Joined: Apr 2007
Posts: 375
Likes: 0
From: Glenwood, IA
