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Author Topic:   metric rearend
track_trash_66
Dirt Full Roller

Total posts: 50
posted March 12, 2005 05:16 PM  
today i moved the holes on my upper control arms on a metric rearend i moved them foward 1 inch than welded washers on. has anyone ever done this and was an inch to much?

bobaluuu
Dirt Freak

Total posts: 474
posted March 12, 2005 05:45 PM  
No one know the answer to that for sure. a
cheap angle finder from lowes or home depot will better answer your question. Mine was less than 10 dollars.

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Light it up, Baby!

HamilRacingTeam
Dirt Roller

Total posts: 24
posted March 12, 2005 08:17 PM  
i have a metric monte and run in a stock class, cant change much, but what should the angles be close to and what effects do the different angles have on the car, please pretend i'm stupid!!!

track_trash_66
Dirt Full Roller

Total posts: 50
posted March 13, 2005 04:39 AM  
i dont know exactly what the angle should be but it gives the car more foward bite. my buddy moved his the same amount i did and didnt have any problems.actually won alot of races. i think i remember reading that the angle should be like 6 deg but i could be wrong.

sc1 racing
Dirt Freak

Total posts: 419
posted March 13, 2005 05:56 AM  
if you didnt pay attention you more than likely changed the wheel base on the car. need to make sure the rearend is still centered in the humps in the frame and that the springs are sitting straight..

any where from 4 to 6 degrees down on the pinion is more than enough, any more you are just putting more wear and stress on u joints...not good. cause they will hold up all year till one night you feel like nothing can stop you...LOL

DAYTONA392005
Dirt Roller

Total posts: 9
posted March 13, 2005 06:20 PM  
The amount of pinon angle needed is a 64 dollar question.
Track conditions is the determining factor.
For instance a heavy track doesn't require as much as a dry slick or muddy track does.
Best thing to do is play with it and find the best compromise to work well all the way around unless rules allow adjustable controll arms.

racin78p
Dirt Freak

Total posts: 333
posted March 13, 2005 06:24 PM  
DAYTONA is right on. We moved our top holes forward one inch and it made a big time difference. For the better. My 85 Regal gets it in the corners now. Dry slick, 4/10's high banked track where I run. Just play with it a little at a time and check the difference. Write it all down so you will know for the future. Race on.

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racin78p
if it ain't fun, then don't run

racin78p
Dirt Freak

Total posts: 333
posted March 13, 2005 06:29 PM  
Oh, forgot to add my pinion angle is at 7 degrees now. Couldn't see what the upper control arm angle ended up, but I was more concerned with pinion angle anyway.

Hope this helps partner.

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racin78p
if it ain't fun, then don't run

o5racer
Dirt Freak

Total posts: 402
posted March 13, 2005 07:52 PM  
Not trying to start a flame war but how exactly does putting more angle in the u-joint make more traction? By moving the the upper bolts on the rearend forward the only change is pinion angle. This has been brought up more times than I can remember and Not once has anyone been able to list any specific reason why. The usual answer is "well bob did it on his car and it works for him". If the only change is pinion angle without changing arm angles then how does it make more traction?
Nick

jay116
Dirt Freak

Total posts: 428
posted March 13, 2005 08:43 PM  
Ya what jay116 is correct. If your static setting is 6 degrees,when you apply power the rearend housing at the yolk end lifts and if everything is set correctly the pinion angle winds up at "0" degrees. In theory this creates the least friction and allows the most power to to reach the rear wheels.

Eljojo
Dirt Forum Champ
Total posts: 968
posted March 14, 2005 04:17 AM  
You got a SBC kicking out around 400 hp and about that in ft lbs of torque and you think that changing the aspect angle of the u-joint gives you more usable power?
The ONLY reason to change the pinion angle is to change the geometry of the upper and lower trailing arms soo that, upon acclelertion, the rear bars try to lift the weight of the car. This "lifting" generates traction thru leverage.

jay116
Dirt Freak

Total posts: 428
posted March 14, 2005 06:51 AM  
God I knew it. Here goes the big debate on pinion angle and what it does to the car!

The last time this was debated on here, I had just joined this forum.

Okay, I actually agree with both main points here. If the pinion angle is correct you will not loose as much power to the rear wheels because driveline is straight, not angled up or down.

By moving the mounting points on the upper control arms, pinion angle can be changed. ALSO though by moving the mounting points on the uppers it can help lift the body when accelerating. This in turn puts more work force on the rear end (tires) and hopefully getting more forward bite.

All I know for sure is I changed my mounting locations on the upper control arms and the car hooks up like a bad boy now when getting out of the corners. Before it would tend to just smoke both right and left tires. I went through alot of them before getting them hooking up. Race on.

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racin78p
if it ain't fun, then don't run

track_trash_66
Dirt Full Roller

Total posts: 50
posted March 14, 2005 06:34 PM  
thanks everyone, what i did is i got 2 sets of uppers and moved one set half an inch and one set one inch, put the ones with half inch on first.and go from there

Eljojo
Dirt Forum Champ
Total posts: 968
posted March 15, 2005 05:07 AM  
I LOVE this place!
Good luck-----I am sure you have helped your forward bite.

    

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