Pinion angle adjustment Questions

Everything from the motor to the wheels

Moderator: John_Heard

Message
Author
grandville455
Posts: 176
Joined: Sat Sep 13, 2008 9:11 am

Pinion angle adjustment Questions

#1 Post by grandville455 » Sun Mar 13, 2011 8:57 am

Getting closer to getting the car movable again, Now last year when i checked the pinion angle with other rearend with the Constant Velocity driveshaft and street tires it was about -2,-3 On the very back joint I think? I never checked with my Slicks, and We know it went 1.63... Ok Now this year got the 9" in and checking pinion in back with same tires sitting at ride height(taller coils in back look to be about a 1 1/4" taller by looking at fender pic now( 26 1/4") compared to last year's 25'' and other coils,and its at -2 right now with very little adjustment left on the upper arms, Can't go anymore negative . That is with it sitting right on the bottom of the yoke as I have no shaft in it yet. So With shaft out I checked the trans angle just attaching it to the back of the flange on trans, and it is -4. I have never checked the trans until today so keep that in mind. So I know I need to check it with the slicks and I will, But For right now please explain where I am at now. Is it close to being good? If I am understanding it right. I am at -6 right now? Which would have been where I was last year! I would say I was loosing 60 ft from that alone! Or maybe that is where that constant velocity set up really helped it? Does the angle go up or down with taller tires? Being that trans is -4 Do I then need to set the Pinion Yoke about +2 or +3 so it will be close to +4 to match the -4 on the trans when under power?
9 inch taller coils.jpg
[attachment=0]9 inch taller coils.jpg
Attachments
buick shorter coils.jpg
74 Pontiac Grandville
7.33- 1/8th @ 94.55/ 11.501 @117.74- 4550 pds
1.60 60 ft....all bests

74 Firebird 3580#
2016 1.377 60ft, 6.33@106.87- 10.02@ 132 mph

User avatar
Craig W.
Posts: 1254
Joined: Thu May 12, 2005 11:01 am
Location: Columbia, KY
Contact:

Re: Pinion angle adjustment Questions

#2 Post by Craig W. » Sun Mar 13, 2011 12:37 pm

First, tire height has nothing to do with it. 2nd, without the driveshaft in it, you can't know the working angle of each u-joint. Its not the actual angle to the ground but the working angle of the joint.

In a street car, you want the rearend and trans angles to be close to the same to cancel harmonics. For a drag car, you're typically more worried about the rear joint angle. With a factory 4-link style setup with solid bushings, 2 degrees negative should be a very good starting point. But you may not have that since the driveshaft isn't in it.
Craig Watson
2QuickNovas Racing
5.27@130

Sponsors:
AEM Electronics
Carnivore Performance
Bradco Converters
Rapp Racing
VFN Fiberglass

grandville455
Posts: 176
Joined: Sat Sep 13, 2008 9:11 am

Re: Pinion angle adjustment Questions

#3 Post by grandville455 » Sun Mar 13, 2011 2:04 pm

So I need to get the drivshaft built first? According to this site i don't measure with the driveshaft in? This is all new to me so trying to figure out the correct method to set it up. I am using UMI ultimate upper arms, UMI boxed lower's with their poly bushings in, and just plain old new rubber ones in the rear end itself for the upper ears, So What I am asking is if my trans is -4 would I then set the yoke at +2 So that under power it would get closer to being parallel then? This is new to me so please forgive my lack of knowledge


http://www.rosslertrans.com/Pinion%20angle.htm
74 Pontiac Grandville
7.33- 1/8th @ 94.55/ 11.501 @117.74- 4550 pds
1.60 60 ft....all bests

74 Firebird 3580#
2016 1.377 60ft, 6.33@106.87- 10.02@ 132 mph

User avatar
Craig W.
Posts: 1254
Joined: Thu May 12, 2005 11:01 am
Location: Columbia, KY
Contact:

Re: Pinion angle adjustment Questions

#4 Post by Craig W. » Sun Mar 13, 2011 2:56 pm

It depends on if you are setting it up mainly for the street for for the track.

For the street, you can make the center line of the rearend parallel to the center line of the tranny. Under light load, it'll make for the smoothest drive.

For the track, you want about -2 to -4 (with a factory 4-link) degrees in relation to the driveshaft. I've got an article on it at www.2quicknovas.com/tech.html that has a diagram that explains it.

With rubber bushings in the upper rear, the rearend will move more and you'll need a little more pinion angle. So probably closer to -4 for your setup.
Craig Watson
2QuickNovas Racing
5.27@130

Sponsors:
AEM Electronics
Carnivore Performance
Bradco Converters
Rapp Racing
VFN Fiberglass

grandville455
Posts: 176
Joined: Sat Sep 13, 2008 9:11 am

Re: Pinion angle adjustment Questions

#5 Post by grandville455 » Sun Mar 13, 2011 4:43 pm

I am setting it up for street /strip Its my car in my sig. So If I understand you correctly Being that my trans /engine is -4 degrees taken at the back of the trans seal with angle finder, I would then set my Pinion yoke to 0 +1, thinking my Pinion will rotate 3 degrees up under power to match my -4 centerline of trans making pinion centerline +4 correct?... The arms I am using are in the pic
Attachments
Upper control arms.jpg
74 Pontiac Grandville
7.33- 1/8th @ 94.55/ 11.501 @117.74- 4550 pds
1.60 60 ft....all bests

74 Firebird 3580#
2016 1.377 60ft, 6.33@106.87- 10.02@ 132 mph

User avatar
Craig W.
Posts: 1254
Joined: Thu May 12, 2005 11:01 am
Location: Columbia, KY
Contact:

Re: Pinion angle adjustment Questions

#6 Post by Craig W. » Sun Mar 13, 2011 5:11 pm

Most people don't like the possibility of the pinion going "nose up" (positive angle) for an on-track setp. I've never run it like that. But its not nose up compare to the ground that counts. Its nose up compared to the driveshaft. If the driveshaft is 5 degrees down (from tranny to rearend) and the rearend is 2 degrees up, that's -3 pinion angle.

For a purely street setup, you'd put your rearend 4 degrees up to match the tranny's 4 degrees down. That works great in street rods, cruisers and daily drivers. But its not the hot setup for on-track performance.

I'd go -3 degrees at the rear u-joint since this car will be on the strip. But you'll need the driveshaft to know when you have -3 deg.
Craig Watson
2QuickNovas Racing
5.27@130

Sponsors:
AEM Electronics
Carnivore Performance
Bradco Converters
Rapp Racing
VFN Fiberglass

grandville455
Posts: 176
Joined: Sat Sep 13, 2008 9:11 am

Re: Pinion angle adjustment Questions

#7 Post by grandville455 » Sun Mar 13, 2011 5:29 pm

Ok sounds good!.But I guess I don't understand why I would need the shaft if I already know the trans angle of -4? that isn't going to change when i slide the shaft in. I am calling the guy tomorrow with the measurments for the shaft, I took it from the seal to that front of the yoke 62 3/8, he said he can figure it out from there. Old driveshaft was 66 1/2" from slip yoke end to the flange end, Now with the 9" and a 1350 style yoke in back its going to be shorter cause it doesn't have that double joint in back anymore. Do U think I would be safe with a 3" .083 wall. or should i try for the 3 1/2? I have about a 1/4 it looks like to bottom of loop if i go that big u think its ok? I would feel better with the critical speed of the bigger shaft, I will be going thru about 5500 or so.
Attachments
shaft.jpg
74 Pontiac Grandville
7.33- 1/8th @ 94.55/ 11.501 @117.74- 4550 pds
1.60 60 ft....all bests

74 Firebird 3580#
2016 1.377 60ft, 6.33@106.87- 10.02@ 132 mph

User avatar
Craig W.
Posts: 1254
Joined: Thu May 12, 2005 11:01 am
Location: Columbia, KY
Contact:

Re: Pinion angle adjustment Questions

#8 Post by Craig W. » Sun Mar 13, 2011 9:47 pm

You need the driveshaft, or somewhat to mock it up, in order to know the working angle of the rear u-joint. Take a look at the graphic I have in my article that I linked to earlier and it'll show you.

How much power are you making? How heavy is the car? What size slick?
Craig Watson
2QuickNovas Racing
5.27@130

Sponsors:
AEM Electronics
Carnivore Performance
Bradco Converters
Rapp Racing
VFN Fiberglass

grandville455
Posts: 176
Joined: Sat Sep 13, 2008 9:11 am

Re: Pinion angle adjustment Questions

#9 Post by grandville455 » Mon Mar 14, 2011 5:25 am

I looked at that pic, and that is where I get confused, whats the difference of taking the angle off the back of the seal flange on trans and off the flat of the yoke in back Then taking it off the diriveshaft? If the trans is at -4 isn't the driveshaft also going to be that coming into the yoke? I also always thought pinion was the difference between the shaft and the rearend? In your pic u show it as the two added together? Roughly 560-580 hp? 600 ftlbs 3.89 gear with a low gear set in trans with a 28x10x15 stiffwall mickey Drag slick, last year it was about 4550-4600 pds ,but i got rid of stock tank and using a cell now in trunk, have not weighed it yet but i am guessing with the 35 splines etc it will still be close to that!
I talked to my driveshaft guy and he said kinda what u are with using the shaft, he said u don't want anymore than 2 degrees difference from the front u joint working angle to the back working angle taken from the driveshaft in front and back.
74 Pontiac Grandville
7.33- 1/8th @ 94.55/ 11.501 @117.74- 4550 pds
1.60 60 ft....all bests

74 Firebird 3580#
2016 1.377 60ft, 6.33@106.87- 10.02@ 132 mph

User avatar
Craig W.
Posts: 1254
Joined: Thu May 12, 2005 11:01 am
Location: Columbia, KY
Contact:

Re: Pinion angle adjustment Questions

#10 Post by Craig W. » Mon Mar 14, 2011 9:13 pm

Not sure I'm understanding you right but are you thinking the driveshaft will be at the same angle as the trans? Its highly unlikely that it will be.

I think a 3" drivehshaft will be OK.
Craig Watson
2QuickNovas Racing
5.27@130

Sponsors:
AEM Electronics
Carnivore Performance
Bradco Converters
Rapp Racing
VFN Fiberglass

grandville455
Posts: 176
Joined: Sat Sep 13, 2008 9:11 am

Re: Pinion angle adjustment Questions

#11 Post by grandville455 » Tue Mar 15, 2011 6:02 am

Yea That was my thought ,but the more i look at things etc, your right the driveshaft will be angling down more to set at the rear. I wasn't thinking straight ,lol. I decided to just do the 3.5 and be done with it, According the mark williams site with a driveshaft of 58 ctc the critical speed is still only like 5800 I think with a 3.5. How much power do u loose thru the extra weight? mine now is stock 2 3/4 on each end and 3 in the middle and its heavy now!
74 Pontiac Grandville
7.33- 1/8th @ 94.55/ 11.501 @117.74- 4550 pds
1.60 60 ft....all bests

74 Firebird 3580#
2016 1.377 60ft, 6.33@106.87- 10.02@ 132 mph

User avatar
Craig W.
Posts: 1254
Joined: Thu May 12, 2005 11:01 am
Location: Columbia, KY
Contact:

Re: Pinion angle adjustment Questions

#12 Post by Craig W. » Tue Mar 15, 2011 8:52 pm

I doubt you'll notice any measurable loss of performance with the bigger driveshaft.
Craig Watson
2QuickNovas Racing
5.27@130

Sponsors:
AEM Electronics
Carnivore Performance
Bradco Converters
Rapp Racing
VFN Fiberglass

grandville455
Posts: 176
Joined: Sat Sep 13, 2008 9:11 am

Re: Pinion angle adjustment Questions

#13 Post by grandville455 » Fri Mar 18, 2011 8:38 pm

Well After I took the car off the stands in back under rear I have 3 degrees pinion angle. My driveshaft coming into pinion is at 3 degrees, and my pinion is at 0 degrees. Hard to see in pics , took with my phone.Can't go anymore as there is no adjustment left in upper arms.. My new driveshaft is very nice also!. 3 1/2 inches 1350 spicer Joints both ends, spicer slip yoke up front,Spicer 3/8" U joint straps too, balanced .083 wall... $330
Attachments
Driveshaft.jpg
Pinion angle.jpg
Driveshaft angle.jpg
74 Pontiac Grandville
7.33- 1/8th @ 94.55/ 11.501 @117.74- 4550 pds
1.60 60 ft....all bests

74 Firebird 3580#
2016 1.377 60ft, 6.33@106.87- 10.02@ 132 mph

User avatar
Craig W.
Posts: 1254
Joined: Thu May 12, 2005 11:01 am
Location: Columbia, KY
Contact:

Re: Pinion angle adjustment Questions

#14 Post by Craig W. » Fri Mar 18, 2011 9:05 pm

I'd leave it at 3. Should work fine.
Craig Watson
2QuickNovas Racing
5.27@130

Sponsors:
AEM Electronics
Carnivore Performance
Bradco Converters
Rapp Racing
VFN Fiberglass

grandville455
Posts: 176
Joined: Sat Sep 13, 2008 9:11 am

Re: Pinion angle adjustment Questions

#15 Post by grandville455 » Fri Mar 18, 2011 9:10 pm

Thanks! Did I DO IT RIGHT?
74 Pontiac Grandville
7.33- 1/8th @ 94.55/ 11.501 @117.74- 4550 pds
1.60 60 ft....all bests

74 Firebird 3580#
2016 1.377 60ft, 6.33@106.87- 10.02@ 132 mph

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest