AWD Motorsports driveshaft on the BadBish
Aug 20, 2010, 05:48 PM
#76
I have a hard time believing you found the noise produced from solid aluminum diff mounts as a street friendly item. Even buschur himself said it was the worst part on his car. I don't drive my car a whole lot but when I am driving it, I find myself wishing the noise wasn't there.
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.
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.
The part works and works well. You seem to be the only person that found they needed to make their own part because it didn't meet your expectations.
I'm with Mike on this one, I'm also not an engineer of any sorts, but the cars I put together always run well. I don't have any formulas for that...sorry.
Aug 20, 2010, 06:40 PM
#77
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Fun thread, good fights, good info. I was here at EvoM for a different reason but noticed it at the top of the pile.
I just installed the AWD Motorsports driveshaft a couple of weeks ago, cos the boot on the lobro joint (the rear most one) had disintegrated years ago and it was starting to look (and feel) like the joint was on its way. Maybe something to do with several dozen rallycrosses, long trips on dirt roads and so forth. I prefer upgrade to replace, and I'd had my eye on the Devo DS before they disappeared.
Anyway, the lightweight driveshaft was a very easy install and it's a well-engineered piece of kit. I could definitely feel an immediate difference. My butt isn't accurate enough to specify a HP gain, but I do know my car really well - had it from new, 87k and DD for well over 7 years - and I can tell when something changes. It's more or less stock engine-wise, incidentally, and among the earliest of Evo 8s - i.e. no ACD.
I'd run through the same thought process on 'why a 3-piece DS in the first place'. I'd assumed NVH, but the longitudinal movement bears some thought. I remember that there was an awful lot of slop in the driveline when I first got the car, some of which I've counteracted with engine dampers and mounts and stuff (with the downside of increased NVH of course). I still have the core, I'll see how much the LJ will allow the stock driveshaft to grow.
Anyway, I've done one event in it so far (Ken Block's Gymkhana Grid media/test day) and it performed admirably. I'll be interested to see what happens in a rallycross situation - I can always use more response there. I don't do much in the way of drag racing, but I know it can pull a measured ~4.8s 0-60s repeatably, although it's not something I do on a regular basis. It'll be interesting to see what it'll do next time I have a "closed course" to try it.
I just installed the AWD Motorsports driveshaft a couple of weeks ago, cos the boot on the lobro joint (the rear most one) had disintegrated years ago and it was starting to look (and feel) like the joint was on its way. Maybe something to do with several dozen rallycrosses, long trips on dirt roads and so forth. I prefer upgrade to replace, and I'd had my eye on the Devo DS before they disappeared.
Anyway, the lightweight driveshaft was a very easy install and it's a well-engineered piece of kit. I could definitely feel an immediate difference. My butt isn't accurate enough to specify a HP gain, but I do know my car really well - had it from new, 87k and DD for well over 7 years - and I can tell when something changes. It's more or less stock engine-wise, incidentally, and among the earliest of Evo 8s - i.e. no ACD.
I'd run through the same thought process on 'why a 3-piece DS in the first place'. I'd assumed NVH, but the longitudinal movement bears some thought. I remember that there was an awful lot of slop in the driveline when I first got the car, some of which I've counteracted with engine dampers and mounts and stuff (with the downside of increased NVH of course). I still have the core, I'll see how much the LJ will allow the stock driveshaft to grow.
Anyway, I've done one event in it so far (Ken Block's Gymkhana Grid media/test day) and it performed admirably. I'll be interested to see what happens in a rallycross situation - I can always use more response there. I don't do much in the way of drag racing, but I know it can pull a measured ~4.8s 0-60s repeatably, although it's not something I do on a regular basis. It'll be interesting to see what it'll do next time I have a "closed course" to try it.
Aug 20, 2010, 07:00 PM
#79
I really don't mind the noise from the solid mount at all, I run the AMS unit. Of course I'm also not some **** e-warrior that has to try to **** all over everybody with my "exterme" intelligence...I asked a simple question to try to verify I was understanding what you were saying. The quipy ******* answers aren't needed.
The part works and works well. You seem to be the only person that found they needed to make their own part because it didn't meet your expectations.
I'm with Mike on this one, I'm also not an engineer of any sorts, but the cars I put together always run well. I don't have any formulas for that...sorry.
The part works and works well. You seem to be the only person that found they needed to make their own part because it didn't meet your expectations.
I'm with Mike on this one, I'm also not an engineer of any sorts, but the cars I put together always run well. I don't have any formulas for that...sorry.
I hope you enjoy your $700 driveshaft...not all of use are fools with money though. I'm a broke fool...
Maybe later I'll post up the spicer part numbers that you need to do it with, including tube length.
Last edited by 03whitegsr; Aug 20, 2010 at 09:23 PM.
Aug 20, 2010, 07:39 PM
#81
You know, I wasn't going to say it because it is kind of pissing on somebody else's business, but the hell with it.
How about this, I went to a local driveshaft shop and they built me a 2-piece driveshaft similar to this for $250 in 2 days.
I hope you enjoy your $700 driveshaft...not all of use are fools with money though. I'm a broke fool...
Maybe later I'll post up the spicer part numbers that you need to do it with, including tube length.
How about this, I went to a local driveshaft shop and they built me a 2-piece driveshaft similar to this for $250 in 2 days.
I hope you enjoy your $700 driveshaft...not all of use are fools with money though. I'm a broke fool...
Maybe later I'll post up the spicer part numbers that you need to do it with, including tube length.
I imagine I will enjoy my driveshaft, I have no plans on putting 100K on the car and the beating it will take at the strip will surely break stuff prematurely.
I understand that clearly you have more schooling than me, I'm just trying to put the information together so I can understand it. Felt like I was being bashed for not being an engineer
Aug 20, 2010, 08:02 PM
#82
I wasn't bashing you at all. On your first question, I honestly just didn't understand what you were asking. Although it reeked of some kind of contempt or maybe just AWDmotorsports fanboy enthusiasm?
The response was not meant to induce an argument though.
R/T Ernie, just take your driveshaft to a competent driveline shop, they can figure it out. I haven't been able to find the reciept with part numbers, but it wasn't anything special. The $250 special is a steel 2-piece. To go aluminum, it was going to be ~$100 more and they didn't have the parts in stock so it was going to be a week or two.
The biggest weakness in all of these though is that they all use some form of stock front shaft. I've been working up a way to go aluminum on both shafts to get the weight down even further, but it requires a carrier bearing section that is a little more involved then if you used a steel shaft up front.
The response was not meant to induce an argument though.
R/T Ernie, just take your driveshaft to a competent driveline shop, they can figure it out. I haven't been able to find the reciept with part numbers, but it wasn't anything special. The $250 special is a steel 2-piece. To go aluminum, it was going to be ~$100 more and they didn't have the parts in stock so it was going to be a week or two.
The biggest weakness in all of these though is that they all use some form of stock front shaft. I've been working up a way to go aluminum on both shafts to get the weight down even further, but it requires a carrier bearing section that is a little more involved then if you used a steel shaft up front.
Aug 20, 2010, 08:07 PM
#83
I had a shop today tell me they dropped .3 with the driveshaft at the 1/4 mile.. Im bad with names so i need to look back at the order to recall who but i will ask them to post up.. They actually ordered 2 DS for their Time attack cars and i gave them a good deal and asked if they can give any data on lap times with ours vs. Stock.. They said they will try and get us some accurate data with the new shaft as far as what time they dropped in TA and which track etc..
Mike
Mike
Aug 20, 2010, 08:09 PM
#84
I wasn't bashing you at all. On your first question, I honestly just didn't understand what you were asking. Although it reeked of some kind of contempt or maybe just AWDmotorsports fanboy enthusiasm?
The response was not meant to induce an argument though.
R/T Ernie, just take your driveshaft to a competent driveline shop, they can figure it out. I haven't been able to find the reciept with part numbers, but it wasn't anything special. The $250 special is a steel 2-piece. To go aluminum, it was going to be ~$100 more and they didn't have the parts in stock so it was going to be a week or two.
The biggest weakness in all of these though is that they all use some form of stock front shaft. I've been working up a way to go aluminum on both shafts to get the weight down even further, but it requires a carrier bearing section that is a little more involved then if you used a steel shaft up front.
The response was not meant to induce an argument though.
R/T Ernie, just take your driveshaft to a competent driveline shop, they can figure it out. I haven't been able to find the reciept with part numbers, but it wasn't anything special. The $250 special is a steel 2-piece. To go aluminum, it was going to be ~$100 more and they didn't have the parts in stock so it was going to be a week or two.
The biggest weakness in all of these though is that they all use some form of stock front shaft. I've been working up a way to go aluminum on both shafts to get the weight down even further, but it requires a carrier bearing section that is a little more involved then if you used a steel shaft up front.
I apologize for going off. I've spent the better part of my life wrenching on cars, not on the engineering side. I take interest in all of the technical info, sometimes it just takes a bit for me to put all the numbers/data together and trying to picture it all.
Aug 20, 2010, 09:27 PM
#85
Like I said, my viewpoint is probably biased because of 20+ years in the maintenance and engineering side of mfg. Just seen one too many over-engineered machines and have developed a disposition that greatly favors simple robust solutions.
I DD the car some, but it's becoming more and more of a weekend HPDE car.
I've got the Energy bushing kit in the garage for the rear diff whenever I feel froggy enough to tackle it. May have to find someone with a lift. I agree that with a lot of rear diff movement, the CV joint does serve a purpose.
I DD the car some, but it's becoming more and more of a weekend HPDE car.
I've got the Energy bushing kit in the garage for the rear diff whenever I feel froggy enough to tackle it. May have to find someone with a lift. I agree that with a lot of rear diff movement, the CV joint does serve a purpose.
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.
Aug 20, 2010, 10:59 PM
#86
just jokingprops to you for making it yourself man, like alot of guys here i wrench more than i engineer. its always great to hear the other side of it, sincerely. im in no way patronizing you or speaking sarcastically, the internet has a way of making it look that way.
Mike has helped me realize the goals for my evo since i was on my second tour of iraq. He has a great shop and team and a genuine love for racing cars and taking care of his customers. He is one of the must honest guys i know in the business and has one of the best evo shops in the country. I support his parts and shop as my loyalty lies with those who are loyal to me. he has never steered me wrong with anything, parts or build wise and i trust him in that aspect.
he made a great part and filled a void. could it be improved? probably, does it work for what it is? i think so. is it for everyone? of course not, we all do different things with our cars. i had great success with it as do must people that buy it and use it. is it a bit pricey? sure maybe a bit. but if your willing to pay for it, IMHO its worth every penny. Ive known Mike for a bit now and i dont think he would rape me on a driveshaft. He gotta eat and we want good parts that help us go faster. it works out.
You do bring up great points and valid ones at that. i learn alot from guys with experience like you in this aspect, its what makes this website so great. ive owned a few evo's now, from my full group n spec evo 3 and evo 4 in jamaica to my 8 and 9 and hopefully a 10 and i continue to learn about them and how to make them work better. Mike's done alot of testing on this DS, he had it for a good 3 months on the race car and the white car before he released it. with tons of dyno pulls and track and street driving on it, he thought it was safe and worth the investment. i loved mine and thought it was worth every penny of what i paid for it, it was a little less than $700 at the time as i think i was one of the first guys to get one actually and i think i had bought a good chunk of parts by that point that day
ok im off my soap box
Aug 28, 2010, 09:47 PM
#90
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Just some random numbers I came up with while doing my own 2-piece shaft.
60mm 2mm wall 1020 tube (stock)
Moment of inertia (12" length) = 9.43 kg/m^4
Torsional Stiffness = 103kN-m/rad
Failure Torque = 4243 N-m
3" 0.125 wall aluminum tube
Moment of inertia (12" length) = 8.01E-04 kg/m^4
torsional Stiffness = 82kN-m/rad
Failure Torque = 7048 N-m
2.5" 0.083 wall 4130 Chromoly steel tube
Moment of inertia (12" length) = 9.18E-04 kg/m^4
torsional Stiffness = 100kN-m/rad
Failure Torque = 5557 N-m
Larger diameter aluminum OWNS on all aspects...
Even though the actual weight is only 6% less, that aluminum shaft has about 12% less inertia then the steel DEVO shaft.
It will also absorb more of the driveline shock on a launch or hard shift.
60mm 2mm wall 1020 tube (stock)
Moment of inertia (12" length) = 9.43 kg/m^4
Torsional Stiffness = 103kN-m/rad
Failure Torque = 4243 N-m
3" 0.125 wall aluminum tube
Moment of inertia (12" length) = 8.01E-04 kg/m^4
torsional Stiffness = 82kN-m/rad
Failure Torque = 7048 N-m
2.5" 0.083 wall 4130 Chromoly steel tube
Moment of inertia (12" length) = 9.18E-04 kg/m^4
torsional Stiffness = 100kN-m/rad
Failure Torque = 5557 N-m
Larger diameter aluminum OWNS on all aspects...
Even though the actual weight is only 6% less, that aluminum shaft has about 12% less inertia then the steel DEVO shaft.
It will also absorb more of the driveline shock on a launch or hard shift.
Check me if I'm wrong but I believe you want to use polar moment of inertia to describe this J=(pi *r^4)/2 (have to subtract the inner portion and multiply by material density)
In which case it may be similar but the aluminum shaft having a larger outer diameter increases its moment but it's density will decrease it. I haven't crunched the numbers and at the end of the day it may be exactly what you wrote.
http://en.wikipedia.org/wiki/Polar_moment_of_inertia
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