quote:

Originally posted by "The Bender":
A four link with four equal length bars won't change pinion angle. A four link with two longer and two shorter bars will change pinion angle.

The most extreme example of this is GM and fox body mustangs with short upper arms and long lower arms.

A parallel 4 link will change pinion angle. Depends on the application and how long of a shock the car has. Our Pro 275 cars have shocks with 9 to 11” of stroke, almost all of that in extension. We have to set the cars up very unconventional to account for the extreme pinion angle change…much more change than a factory triangulated 4 link like the g-body & fox Mustang.

I think many people make way too much out of pinion angle…, just my .02.

quote:

Originally posted by Fabman:

quote:

Originally posted by "The Bender":
A four link with four equal length bars won't change pinion angle. A four link with two longer and two shorter bars will change pinion angle.

The most extreme example of this is GM and fox body mustangs with short upper arms and long lower arms.

A parallel 4 link will change pinion angle. Depends on the application and how long of a shock the car has. Our Pro 275 cars have shocks with 9 to 11” of stroke, almost all of that in extension. We have to set the cars up very unconventional to account for the extreme pinion angle change…much more change than a factory triangulated 4 link like the g-body & fox Mustang.

I think many people make way too much out of pinion angle…, just my .02.

You said parallel bars, I was talking about equal length bars. The racecar four links I've seen are closer to equal length, but the top bar is usually shorter, but not as extreme as a factory setup....

Also when the pinion angle changes it is no longer at the same angle as the crankshaft angle (depending on at what point of suspension travel the pinion angle is set) and that can cause a vibration.

What brand / type level are racers using to check pinion angle? If digital what brand? The McAmis model SPI TRONIC PRO 360 Digital Level is out of my price range.

quote:

Originally posted by "The Bender":

quote:

Originally posted by Fabman:

quote:

Originally posted by "The Bender":
A four link with four equal length bars won't change pinion angle. A four link with two longer and two shorter bars will change pinion angle.

The most extreme example of this is GM and fox body mustangs with short upper arms and long lower arms.

A parallel 4 link will change pinion angle. Depends on the application and how long of a shock the car has. Our Pro 275 cars have shocks with 9 to 11” of stroke, almost all of that in extension. We have to set the cars up very unconventional to account for the extreme pinion angle change…much more change than a factory triangulated 4 link like the g-body & fox Mustang.

I think many people make way too much out of pinion angle…, just my .02.

You said parallel bars, I was talking about equal length bars. The racecar four links I've seen are closer to equal length, but the top bar is usually shorter, but not as extreme as a factory setup....

Also when the pinion angle changes it is no longer at the same angle as the crankshaft angle (depending on at what point of suspension travel the pinion angle is set) and that can cause a vibration.

While I said parallel I meant equal length. Most of the 4 links I deal with have the upper bars between 20-21 for the top bar and 22 for the lower.

But again, depends on the application and on extreme radial stuff, it’s impossible to keep the pinion on the same angle as the engine/trans and these cars don’t suffer from vibration. Going down track at full speed the pinion and driveshaft are almost lined up (still 1 or so deg down), but also at an extreme angle to the output shaft of the transmission.

Big tire slick cars are different as the rear doesn’t move up and down nearly as much, usually only in compression.

quote:

Originally posted by Fabman:
But again, depends on the application and on extreme radial stuff, it’s impossible to keep the pinion on the same angle as the engine/trans and these cars don’t suffer from vibration. Going down track at full speed the pinion and driveshaft are almost lined up (still 1 or so deg down), but also at an extreme angle to the output shaft of the transmission.

Big tire slick cars are different as the rear doesn’t move up and down nearly as much, usually only in compression.

Does this go back to your statement “I think many people make way too much out of pinion angle”.

quote:

Originally posted by markemark:

quote:

Originally posted by Fabman:
But again, depends on the application and on extreme radial stuff, it’s impossible to keep the pinion on the same angle as the engine/trans and these cars don’t suffer from vibration. Going down track at full speed the pinion and driveshaft are almost lined up (still 1 or so deg down), but also at an extreme angle to the output shaft of the transmission.

Big tire slick cars are different as the rear doesn’t move up and down nearly as much, usually only in compression.

Does this go back to your statement “I think many people make way too much out of pinion angle”.

Probably. Lol.

quote:

Originally posted by markemark:
What brand / type level are racers using to check pinion angle? If digital what brand? The McAmis model SPI TRONIC PRO 360 Digital Level is out of my price range.

Any digital that measures to 2 decimal places will be adequate. The one McCamis sells is super nice, there are others that have the v groove as well and measure very accurately for the application.

Tremec has a cool app for calculating as well.

quote:

Originally posted by BG7X77:

quote:

Originally posted by markemark:
What brand / type level are racers using to check pinion angle? If digital what brand? The McAmis model SPI TRONIC PRO 360 Digital Level is out of my price range.

Any digital that measures to 2 decimal places will be adequate. The one McCamis sells is super nice, there are others that have the v groove as well and measure very accurately for the application.

Tremec has a cool app for calculating as well.

I have /use a $12 magnetic analog protractor from Summit and am able to read it while under my door car. After reading Fabmans recent post I’m going to call what I have good.

Magnetic protractor or you can download an app for your phone

quote:

Originally posted by markemark:
What brand / type level are racers using to check pinion angle? If digital what brand? The McAmis model SPI TRONIC PRO 360 Digital Level is out of my price range.

I just use this little $30 unit from Klein:

https://a.co/d/aXGVOod

https://www.amazon.com/gp/prod...02_s00?ie=UTF8&psc=1

On sale thru Amazon for $23.99

It is magnetic so I put it on the balancer and hit "alt zero". Then I put it on the rear yoke flats and compare.

quote:

Originally posted by Lenny5160:

quote:

Originally posted by markemark:
What brand / type level are racers using to check pinion angle? If digital what brand? The McAmis model SPI TRONIC PRO 360 Digital Level is out of my price range.

I just use this little $30 unit from Klein:

https://a.co/d/aXGVOod

I have the same one. Nice piece.

quote:

Originally posted by Lenny5160:

quote:

Originally posted by markemark:
What brand / type level are racers using to check pinion angle? If digital what brand? The McAmis model SPI TRONIC PRO 360 Digital Level is out of my price range.

I just use this little $30 unit from Klein:

https://a.co/d/aXGVOod

I use the same one, I like the contrast of the display.......