Trans/drive angle ls7 dry sump?
 

Im working with an LS7 in a 69 camaro, my drive angle measured at the crank pulley shows the trans down 4 degrees. Does this seem excessive? If I lift the trans Im smashing the tunnel and this is with a tko 600 install. Just curious if 4 degrees is ok for fluid levels and possible vibration issues?

I believe I will have to lift the rear yoke up 3 degrees(dse 4 link)?

Thanks Rich

That's just fine for the engine, but I can't comment on driveline angles and such. I don't know how the DSE setup is adjusted.

Thanks Matt- I just called dse they to said the trans down 4 degrees is fine, they want me to drop the pinion yoke 2 degrees(downward). I almost fell out of my chair, seems like a lot of angle to me. I figured moving it up would make it more parallel. I wish I understood why?

Rich

Because 4 degrees is not Optimal. With 4 degrees of drivline angle and a good stance like you'll see on my car or bad penny, etc. You will have an UPWARD driveshaft angle with equal and opposite drivline/pinion angles. That means your working angles are getting severe for high speed run out. All you're doing by pointing the pinion down is making the working angles as small as possible. I was able to achieve under 3 degrees of working angle where with equal and opposite you would have 7-8. The driveshaft will actually slope down towards the rear a little which is optimal. Personally, if you are in the fabrication phase? I'd cut that tunnel in a heart beat and set that thing up with equal and opposite numbers. You're going to need 2-3(approx) degree driveline angle to do so. That would allow you to get your working angles between 1-2 degrees which will make your car run out super smooth until you run out of horsepower. I'm not saying it's not possible with 4 degrees of driveline angle, I'm simply saying it's the second best way to skin the cat. Take a look at a modern corvette/camaro etc and take note of the driveline slope.

Rich --

There's a ton of info to be found on all of this via the 'net....

The pinion "down" is kind of a counter action to it wanting to climb under acceleration. The pinion wants to climb the ring gear - so with urethane bushings etc - you'd probably be running 1* down maybe even 0* with bushing deflection. Although this varies with length of the control arms etc... and leaf springs used to really allow the pinion to rise..

Todd wrote about working angles - and these are important and often overlooked. There has to be some working angle in the driveline or the bearings in the U joints won't tumble (probably the wrong use of the word but you'll get the picture) and that leads to premature wear.

Most of the engine installs I've seen are typically "down" 3*'s at the tail shaft. So one more degree isn't really that big of a deal.... If I was building a chassis and installing the engine etc -- I'd be trying to get the carb mounting (as measured on the intake) in that 3* mark.

In the end - and someone jump in here if I'm explaining this incorrectly -- is that you want the driveline angle to be equal to or within around 1* of each other (canceling each other out). So it's more a matter of what that "takes" to get it there. There's only one way to get there - and that is to set it up and measure it. Measure it loaded and unloaded. And you for sure want these angles to be less than 3*'s or you'll just chew up your u-joints.

Todd - Im a thick itralian, If I lift the trans to zero level at my ride height and drop the pinion down 1-2 degrees, would that be optimal? Im thinking it would be nice to drop the pinion a bit to gain clearance in the very back of the tunnel above the yoke/ pinion.

Thanks Rich

Rich --


You're working too much on the angles of the tail shaft vs the pinion angle -- and missing the important steps that are critical.

So --- lets see if I can write this so you can understand.

Engine DOWN 4* -- Driveline DOWN 2*'s -- that "angle" is 4 - 2 = 2* angle

Pinion down 2* - driveline DOWN 1* - that angle is 2 - 1 =1* angle

The one angle is 2* -- minus the other angle of 1* equals the DIFFERENCE is 1*
which would be fine. And this difference can be MAX of 3* (really depends on drive line speeds less for high speed and more for low speed).

So it really doesn't matter what the down angle of the engine is -- or the pinion angle is -- but they MUST relate to each other measuring the angles to get the driveline angle...

Does this make sense?

Rich --

Took me a couple minutes to upload a photo to Photobucket -- but this will help you with this set up process.


http://i919.photobucket.com/albums/a...elineAngle.gif

Greg, that diagram is great for a 4x4 but it simply won't work in this application with 4 degrees of driveline angle. The drivshaft slopes up in that scenario which means you add the working angles, NOT subtract. I tried the 4 degree driveline angle with a pinion angle of 2 degrees and it vibrated like hell.

Rich,
I'm saying to have a 2-3 degree driveline angle and say 1-2 degrees up or pinion anlge. (Within 1 degree for smooth runout) It's whatever get's your working angles in compliance at RIDE HEIGHT.

The diagram shows HOW TO MEASURE -- not the actual angles to use... It's posted to help him understand what's important to be within 'tolerance' and what needs to be measured. From there - he can make the necessary adjustments for his situation.

I was getting the sense that he's 'hung up' on the up down angles of the two components -- without measuring or taking into consideration - the working angles relationship to the driveline.

I totally get the issues with tunnel clearance etc.