driveline/transmission/pinion angle?
12-18-2006, 01:55 AM
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driveline/transmission/pinion angle? In most drivetrains, the transmission is physically higher than the differential, so the transmission angle is positive, and the pinion angle is negative.
Are there any negative repercussions to having the transmission sit lower than the differential (so the transmission angle is negative, and the pinion angle is positive)??
Much like in this picture:
Are there any negative repercussions to having the transmission sit lower than the differential (so the transmission angle is negative, and the pinion angle is positive)??
Much like in this picture:
12-18-2006, 07:14 AM
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From a driveline standpoint, there shouldn't be any problem. The universal joints don't really know or care whether the transmission end of the shaft is higher or lower.
What they do care about is getting the driveline angles correct (pinion vs transmission). In a perfect world, the angles would be always be equal. Sadly, the only way that works / happens is with an IRS and maybe certain 4bar or ladder bar setups (depends upon geometry for both).
Another concern for u-joints is that you don't exceed their mechanical limitations (operating angle). Too much angle and you'll tear up joints in short order. But you also want to make sure the joint does have some angle (like 1 degree) so that you keep the grease moving around (because too little movement will kill joints too).
Leaf spring cars typically need to cheat the pinion down a bit (nose down) so that under power the joint is still close (due to spring wrap, amount will depend upon how stiff / weak your springs are).
You should certainly evaluate the angles in your particular application and make sure that everything is workable. You wouldn't want to need to have the pinion nosed down so far (for the correct angles) that it makes contact with the pavement or has any other issues (like exceeding allowable u-joint angles).
'JustDreamin'
What they do care about is getting the driveline angles correct (pinion vs transmission). In a perfect world, the angles would be always be equal. Sadly, the only way that works / happens is with an IRS and maybe certain 4bar or ladder bar setups (depends upon geometry for both).
Another concern for u-joints is that you don't exceed their mechanical limitations (operating angle). Too much angle and you'll tear up joints in short order. But you also want to make sure the joint does have some angle (like 1 degree) so that you keep the grease moving around (because too little movement will kill joints too).
Leaf spring cars typically need to cheat the pinion down a bit (nose down) so that under power the joint is still close (due to spring wrap, amount will depend upon how stiff / weak your springs are).
You should certainly evaluate the angles in your particular application and make sure that everything is workable. You wouldn't want to need to have the pinion nosed down so far (for the correct angles) that it makes contact with the pavement or has any other issues (like exceeding allowable u-joint angles).
'JustDreamin'
12-18-2006, 09:18 AM
#3
I had a real probem with traction when my pinyon was tipped up too much. my drineline did not vibrate but I just spun the tires alot more. I have corrected this now and I spin less and hook up better. my trans was higher then the rear end.
12-18-2006, 02:08 PM
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The car I'm hoping to do a swap on has an IRS. The pinion angle is very minimal, almost zero. Unfortunately, due to the small transmission tunnel, the T56 and its bellhousing won't fit. I was planning to lower the engine one to two inches, however this would mean the transmission would also sit lower than stock. I have read that the maximum pinion angle is normally around 3*, which I don't think will be a problem.
I suppose I could also have the engine/tranny sit lower in the front than the rear, resulting in trans tunnel clearance, and the transmission output shaft would relatively be in the same place, as compared to stock. The transmission angle however, would vary a few degrees, and the pinion angle would have to change in accordance.
I suppose I could also have the engine/tranny sit lower in the front than the rear, resulting in trans tunnel clearance, and the transmission output shaft would relatively be in the same place, as compared to stock. The transmission angle however, would vary a few degrees, and the pinion angle would have to change in accordance.
12-18-2006, 04:08 PM
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Having the engine and trans sit at an angle the opposite way might be trouble. You'll need to make sure that oil drains properly and that it can get to the oil pan sump (it won't flow uphill). Trans will probably be ok, but I might check with someone who knows the T56 real well, and you may end up having to run more fluid in it (which might cause other problems).
If a small trans tunnel is the cause of the problem, why not work on it as a solution? I'm sure you're going for the easiest answer, which is what I would do. But you might get to the point where the hurdles to moving the engine / trans lower are more difficult than modifying the trans tunnel (which might not be that hard, depending upon your skills and how much room the trans needs).
Just figuring that you should evaluate all your options.
'JustDreamin'
If a small trans tunnel is the cause of the problem, why not work on it as a solution? I'm sure you're going for the easiest answer, which is what I would do. But you might get to the point where the hurdles to moving the engine / trans lower are more difficult than modifying the trans tunnel (which might not be that hard, depending upon your skills and how much room the trans needs).
Just figuring that you should evaluate all your options.
'JustDreamin'
