AWD Motorsports driveshaft on the BadBish
Aug 20, 2010, 12:12 PM
#61
First about the wrenching. I assemble every single engine that we do here, every one, no exception. (OK one, my brother just built his own for his '41 *****'s project). Wrenching to me is pulling engines/transmissions out of cars. Engine assembly is no wrenching.
94awdcoupe,
I'm not sure what you read or what wasn't intelligent about my post but maybe read what I said again:
"We had my RS on the dyno a few years ago, didn't even remove it from the dyno, jacked it up in place, swapped from stock rotors to the original Giro's. That was a total weight loss, all rotating mass, of 15.3 pounds. The car gained 7 whp. I believe those gains 100%.
I don't know how much the driveshaft would gain, some of the loss in weight is from losing a carrier bearing. Measurable? Yes. How much, I can only guess based on the rotor weight numbers."
No where in there am I backing Mike, so you aren't reading correctly. Also 15.3 pounds lost in rotor weight is not the same as the 12 pounds lost driveshaft weight as the driveshaft weight loss also includes a carrier bearing, which I stated. I think you are argueing with the wrong guy here. So read what I said again.
94awdcoupe,
I'm not sure what you read or what wasn't intelligent about my post but maybe read what I said again:
"We had my RS on the dyno a few years ago, didn't even remove it from the dyno, jacked it up in place, swapped from stock rotors to the original Giro's. That was a total weight loss, all rotating mass, of 15.3 pounds. The car gained 7 whp. I believe those gains 100%.
I don't know how much the driveshaft would gain, some of the loss in weight is from losing a carrier bearing. Measurable? Yes. How much, I can only guess based on the rotor weight numbers."
No where in there am I backing Mike, so you aren't reading correctly. Also 15.3 pounds lost in rotor weight is not the same as the 12 pounds lost driveshaft weight as the driveshaft weight loss also includes a carrier bearing, which I stated. I think you are argueing with the wrong guy here. So read what I said again.
Aug 20, 2010, 12:18 PM
#62
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First about the wrenching. I assemble every single engine that we do here, every one, no exception. (OK one, my brother just built his own for his '41 *****'s project). Wrenching to me is pulling engines/transmissions out of cars. Engine assembly is no wrenching.
94awdcoupe,
I'm not sure what you read or what wasn't intelligent about my post but maybe read what I said again:
"We had my RS on the dyno a few years ago, didn't even remove it from the dyno, jacked it up in place, swapped from stock rotors to the original Giro's. That was a total weight loss, all rotating mass, of 15.3 pounds. The car gained 7 whp. I believe those gains 100%.
I don't know how much the driveshaft would gain, some of the loss in weight is from losing a carrier bearing. Measurable? Yes. How much, I can only guess based on the rotor weight numbers."
No where in there am I backing Mike, so you aren't reading correctly. Also 15.3 pounds lost in rotor weight is not the same as the 12 pounds lost driveshaft weight as the driveshaft weight loss also includes a carrier bearing, which I stated. I think you are argueing with the wrong guy here. So read what I said again.
94awdcoupe,
I'm not sure what you read or what wasn't intelligent about my post but maybe read what I said again:
"We had my RS on the dyno a few years ago, didn't even remove it from the dyno, jacked it up in place, swapped from stock rotors to the original Giro's. That was a total weight loss, all rotating mass, of 15.3 pounds. The car gained 7 whp. I believe those gains 100%.
I don't know how much the driveshaft would gain, some of the loss in weight is from losing a carrier bearing. Measurable? Yes. How much, I can only guess based on the rotor weight numbers."
No where in there am I backing Mike, so you aren't reading correctly. Also 15.3 pounds lost in rotor weight is not the same as the 12 pounds lost driveshaft weight as the driveshaft weight loss also includes a carrier bearing, which I stated. I think you are argueing with the wrong guy here. So read what I said again.
Last edited by OneCrzyEvo21; Aug 5, 2011 at 03:37 PM.
Aug 20, 2010, 12:20 PM
#63
For a daily driver, I would either stick to the stock driveline or get a shaft with a joint that can handle axial movement in the rear shaft. Your low mileage failure is not the norm and is a rare case.
If you are building a racecar or weekend warrior that probably won't see 100k miles, a 2-piece like these will be fine. Particularly if the car has a hard mounted rear diff.
Fact of the matter is, that rear CV only allows about 1/8" of axial movement. It has NOTHING to do with TC movement. It is just to deal with rear diff movement, which is minimal on a stock car and non-existent on a car with solid diff mounts. That front slip yoke is where the TC movement is accommodated on a stock car, it IS NOT handled by the rear CV.
Aug 20, 2010, 12:26 PM
#64
I wasn't trying to bash you or anything, 94AWDcoupe looks to be though. I was just pointing out the reasoning behind using a 3-piece driveshaft. As for the KISS mentality, it's the only way to go. It's a driveshaft though, it's pretty simple from the get go. KISS doesn't mean you ignore facts about the system though.
For a daily driver, I would either stick to the stock driveline or get a shaft with a joint that can handle axial movement in the rear shaft. Your low mileage failure is not the norm and is a rare case.
If you are building a racecar or weekend warrior that probably won't see 100k miles, a 2-piece like these will be fine. Particularly if the car has a hard mounted rear diff.
Fact of the matter is, that rear CV only allows about 1/8" of axial movement. It has NOTHING to do with TC movement. It is just to deal with rear diff movement, which is minimal on a stock car and non-existent on a car with solid diff mounts. That front slip yoke is where the TC movement is accommodated on a stock car, it IS NOT handled by the rear CV.
For a daily driver, I would either stick to the stock driveline or get a shaft with a joint that can handle axial movement in the rear shaft. Your low mileage failure is not the norm and is a rare case.
If you are building a racecar or weekend warrior that probably won't see 100k miles, a 2-piece like these will be fine. Particularly if the car has a hard mounted rear diff.
Fact of the matter is, that rear CV only allows about 1/8" of axial movement. It has NOTHING to do with TC movement. It is just to deal with rear diff movement, which is minimal on a stock car and non-existent on a car with solid diff mounts. That front slip yoke is where the TC movement is accommodated on a stock car, it IS NOT handled by the rear CV.
So on a car with a solid mounted diff and stiff urethane engine mounts the issues you are presenting will not be as big of factor?
Just trying to follow on this 
Aug 20, 2010, 12:51 PM
#65
Well, I've actually enjoyed reading this thread so far...a lot of interesting, informative info has been throw around...lets keep it going...So has anyone actually dynoed a car with a stock driveshaft then swapped to the aluminum DS and redynoed?
Last edited by 06MREvo; Aug 20, 2010 at 01:07 PM.
Aug 20, 2010, 01:18 PM
#69
mike, if you dig thru my dyno's (as much as they are) there are pruven gains there, we did my driveshaft and only my driveshaft when we did it. we did gain whp (8-10) but the main thing was responsiveness of the motor and it help spool on the red. its a badass piece, i loed mine when i had my 9, once i get my ten, maybe mike will do something special, lol
Aug 20, 2010, 01:20 PM
#70
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Actually I have to agree with 94AWDcoupe when he says that it's not all about 1/4 mile time, especially with evo's. True evo's are very fast cars and do very good at the 1/4 mile, but it's not what they are designed for. The strongest quality in the evo is its HANDLING on daily driven roads. They're everywhere in the world competing in rally's, hill climps, time attacks, etc... an old dsm will beat the evo in a 1/4, and will cost less to build. It won't stand a chance against an evo in a rally or hill climb though...
Second point is, those 8sec cars are all very expensive to maintain, and very time consuming to maintain... every now and then a part will brake... those are not daily driven cars...
When someone criticises a point, you can't just tell him "look at all the records in my sig, i am right you are wrong"! records are just what they are. A 1/4 mile record means you are good at building a 1/4 mile car. How often do you have to maintain it? how does it behave as a DD? how costly is it to maintain? how fun is it to drive on the road?
Personally I like a torquey DD evo, and can't imagine myself saying about an evo that has peak torque at 6000rpm "oh, it's not too laggy"
Second point is, those 8sec cars are all very expensive to maintain, and very time consuming to maintain... every now and then a part will brake... those are not daily driven cars...
When someone criticises a point, you can't just tell him "look at all the records in my sig, i am right you are wrong"! records are just what they are. A 1/4 mile record means you are good at building a 1/4 mile car. How often do you have to maintain it? how does it behave as a DD? how costly is it to maintain? how fun is it to drive on the road?
Personally I like a torquey DD evo, and can't imagine myself saying about an evo that has peak torque at 6000rpm "oh, it's not too laggy"
I agree on the rest of your post though.
Aug 20, 2010, 01:26 PM
#71
If the resonant frequency is too low, the shaft can potentially rip it's self apart.
As for axial movement, I specifically stated if you have a solid mounted rear diff, that rear CV isn't really needed. If the car is a DD that sees lots of miles, I wouldn't eliminate that rear joint.
I have a solid mounted rear diff and it's not a DD part at all. It is the worst part I've ever put on my car for DD purposes, right with the twin disc quatermaster clutch. They both kick *** in race mode though.
Aug 20, 2010, 01:33 PM
#72
The vibration isn't a noise matter.
If the resonant frequency is too low, the shaft can potentially rip it's self apart.
As for axial movement, I specifically stated if you have a solid mounted rear diff, that rear CV isn't really needed. If the car is a DD that sees lots of miles, I wouldn't eliminate that rear joint.
I have a solid mounted rear diff and it's not a DD part at all. It is the worst part I've ever put on my car for DD purposes, right with the twin disc quatermaster clutch. They both kick *** in race mode though.
If the resonant frequency is too low, the shaft can potentially rip it's self apart.
As for axial movement, I specifically stated if you have a solid mounted rear diff, that rear CV isn't really needed. If the car is a DD that sees lots of miles, I wouldn't eliminate that rear joint.
I have a solid mounted rear diff and it's not a DD part at all. It is the worst part I've ever put on my car for DD purposes, right with the twin disc quatermaster clutch. They both kick *** in race mode though.
i ran the BR mustache bar, BR side diff mounts, hard bushings along the driveshaft and the driveshaft from AWDM. i think thats pretty solid in the rear. i had no rubber or flex anywhere back there. i DD my 9 and never had a problem, you feel the back of the car a bit more, but i never had a problem with any of it. drag, street, auto x, never a issue. i guess im trying to figure out what we are debating the problem is here
Aug 20, 2010, 01:37 PM
#73
Lol you got me there. My point is that the evo was designed for handling not straight line speed... handling and low end torque to come quickly off the tight corners
Aug 20, 2010, 03:18 PM
#74
when you say solid mounted, are you talking about full hard bushings and all? just trying to figure it out
i ran the BR mustache bar, BR side diff mounts, hard bushings along the driveshaft and the driveshaft from AWDM. i think thats pretty solid in the rear. i had no rubber or flex anywhere back there. i DD my 9 and never had a problem, you feel the back of the car a bit more, but i never had a problem with any of it. drag, street, auto x, never a issue. i guess im trying to figure out what we are debating the problem is here
i ran the BR mustache bar, BR side diff mounts, hard bushings along the driveshaft and the driveshaft from AWDM. i think thats pretty solid in the rear. i had no rubber or flex anywhere back there. i DD my 9 and never had a problem, you feel the back of the car a bit more, but i never had a problem with any of it. drag, street, auto x, never a issue. i guess im trying to figure out what we are debating the problem is here
The point is, if it is a car with factory diff mounts that you want to go 100k+ miles without driveline problems, I wouldn't eliminate that rear CV. It is there to deal with movement in the rear diff.
Other wise, have at it.
Aug 20, 2010, 04:06 PM
#75
I never had a problem with the noise, i have a small 10 sub in the trunk and great mids and highs, im a avid music lover,lol. honestly though i never noticed the road noise too much, im sure it was a bit louder than stock but didnt ever really notice it. my o2 dump and exhaust was far louder i think, plus driving around at 30psi on E85 everyday kinda kept me involved enough to not hear it i guess.
i do see your point thou, dont think i dont. it makes perfect sense if there is play in the diff, you'll need that last joint to help with the flex in the driveshaft against the diff. i honestly dont think there is that much play though. even if you dont want to use the solid diff mounts, a set of solid driveshaft bushing should fix any play in the driveshaft and you could still keep your nice quiet diff.
i personally loved the weight savings and solid feel of all the parts together, to each his own thou
i do see your point thou, dont think i dont. it makes perfect sense if there is play in the diff, you'll need that last joint to help with the flex in the driveshaft against the diff. i honestly dont think there is that much play though. even if you dont want to use the solid diff mounts, a set of solid driveshaft bushing should fix any play in the driveshaft and you could still keep your nice quiet diff.
i personally loved the weight savings and solid feel of all the parts together, to each his own thou