Yellow Bullet Forums banner
Cancel
Create thread New Garage Forums

Another pinion angle question

Jump to Latest
18K views 55 replies 23 participants last post by  Topfun99  
#1 ·
I've been all over the net looking for solid info on setting the pinion angle. I've also seen the video that showed how changing the front and back angles can cause the driveshaft to change speeds.

That being said, my engine is on a motor plate / midplate and measuring at the crank pulley shows it's angled back 4 degrees.

Now, going by the info I found on Baseline susp. and Wolfe, I should set my pinion angle at between 1-1.5 degrees with solid bushings.

Since my engine is angled back and not sitting at zero, should I be pointing my pinion up to counteract the downward angle of the engine? I'm thinking that If I were to point it up 2.5 degrees, that would put me within the that 1-1.5 degree window. I could be looking at it all wrong but I'm hoping for some clarification.
 
Save
Reply Quote Like Like
#6 ·
Couldn't tell ya, I never checked at the shaft itself. Just the crankshaft and pinion flange. It was a bit of a pain setting it up though. In order to get my pinion pointed up 2.5 degrees, it rotated my housing around until it touched the back part of the wheel well. I ended up having to shorten the lowers 5 full revolutions to get it centered in the wheel well again.
 
Save
Reply Quote Like Like
#7 ·
The pinion angle is the difference between the driveshaft and the pinion flange. Forget the angle of the engine for now. A guy I know just had a shop "set up" his rear end beacuse they knew better supposedly. Totally his fault for not checking, but come to find out they had it so screwed up, it literally pulled the driveshaft out of the back of the trans and he wrecked the car.
 
#16 ·
Everything worked out for me. With no other changes, I ran my personal bests on Sunday. Pulled my first 1.53 60' on drag radials and ran a 9.80@142 only leaving at 3.5 psi. All my previous 60' times were in the 1.9's. I still have a lot to learn but I'm pleased with everything so far.
 
Save
Reply Quote Like Like
#25 ·
Total ET, I'd like to be in the high 8's on this engine combo. I had never used my transbrake before and had no idea how hard I could hit the tires. I had a really mild boost curve setup. I left on 3.5 and ramped it up to 17 over 10 seconds. Next pass I tried to leave at 5 psi and couldn't hook it. I know there's a ton of ET to be gained with a more aggressive boost curve, even if I don't raise peak pressure. I might hit the track again tomorrow.

boostedbowtie said:
Nice job .
Click to expand...
Thanks man!
 
Save
Reply Quote Like Like
E
#31 ·
406shark said:
As most others have said... forget the driveshaft in figuring your pinion angle.

This video will clearly show why...

https://www.youtube.com/watch?v=gmV4qwLfOMY




Jeff
Click to expand...
This video is EXACTLY why you set your pinion angle based off of crankshaft centerline or mainshaft/tailshaft centerline in the trans relative to the centerline of the pinion shaft in the rear end.

The guys doing the driveshaft angle to the pinion angle are not doing this correctly. If you still think you are after watching this video...keep doing it your way as there is no hope for you at this point! lol There is no arguing physics.

You point the pinion angle down in relation to the crankshaft so that on acceleration, when the pinion lifts up, it is parallel with the crankshaft. Solid bushings are usually in the -1.5 to -2 degree range. Poly bushings are a little more of a downward angle (in relation to the crank center line) and rubber bushings are even more.
 
#22 ·
How does measuring -1.5 degree of pinion angle have nothing to do with setting pinion angle. My drive shaft is level with the ground and my pinions angles down 1.5 degrees what does that have to do with a lifted truck. With solid rod end suspensions the pinion will tilt up 1.0 to 1.5 degrees.

Rubber mounts use more angle poly uses less poly solid less and solid solid uses the least pinion angle because they have the least change in geometry. There is a simple pinion setting guide on wolfe race crafts web site.
 
#28 ·
Just to help make it clear.

The reason we measure the transmission output shaft centerline angle then compare it to the rear pinion yoke angle (with the car's rear suspension in normal location) is because we are looking for the RELATIVE angle between those two centerlines.

We do not care what angle the car is sitting, it doesn't matter as long as the rear suspension is where it belongs with the car sitting on the ground.

We do not care if the driveshaft is level to the ground - it doesn't matter since we are not talking about driveshaft angle.

If we were talking about driveshaft angle, that would be the relative angle between the driveshaft centerline and the transmission's output shaft's centerline.
 
Save
Reply Quote Like Like
M
#32 ·
I think most of the time people get confused with the -2 degree thing, thinking it's -2 degrees in relation to 0 degrees level to the world..

They get a angle finder and base it off what it states is 0 degrees and simply go -2 from there..

I understand what Drag GT is saying, I think he's saying that his engine and driveshaft are both at 0 degrees? and in theory (in perfect world scenario such as this) all you really need to do is set the pinion at -2 (based off the crank center-line and driveshaft because they're both 0) and be done.
 
#34 ·
Resurrecting this old crusty thread. My trans centreline is -4 and the pinion is +1 , so under load the poly bushed Chassisworks 4-link will rise the pinion up to +4 to bring it close to parallel with the trans centreline.
For conversation sake the shaft is -2.5 down to the rear. So that means while cruising around it's not the ideal situation. While cruising with light load the front u-joint operating angle is 1.5* and the rear operating angle is also 1.5 * but the two angles are in the same direction so under light load it won't cancel vibrations out like it will under load. Also something to think about is the fact that the front operation angle will change as the pinion raises the shaft under load. Less angles at the U-joints means more powa to the wheels!
 
Save
Reply Quote Like Like
Yellow Bullet Forums
posts
24M
members
152K
Since
2005
A forum community dedicated to drag racing drivers and enthusiasts. Come join the discussion about racing, builds, pro mods, hot rods, events, turbos, nitrous, superchargers, and more!
Full Forum Listing
Explore Our Forums
Trash Or Be Trashed Naturally Aspirated Let's Talk Drag Racing Turbo Charged Nitrous - Induction Solutions