This is one of the best LSD designs on the market imo. It's a gear type differential that you wouldn't have to rebuild every couple of years. They also provide a warranty.
Trying to gauge initial interest to see if this would be possible.
Re: Interest Thread: Wavetrac Front Differential LSD
Re: Interest Thread: Wavetrac Front Differential LSD
I don't see this listed in their applications. Are they considering adding it....or is it just a one time thing. If we can't get a GP together....have you talked to them about if they would do one off's?
Re: Interest Thread: Wavetrac Front Differential LSD
Re: Interest Thread: Wavetrac Front Differential LSD
They said they would consider doing a run of them if interest was high enough.
We need 20 people with 10 willing to prepay.
My hope is between sy/ty, s10 and tbss there will be enough people. Hopefully more then enough to lower the price.
One-offs are unlikely as the expense would be very, very high.
I'm really surprised there isn't more interest in this already. I thought there would be more guys wanting to take full advantage of their awd. This is nothing like a locker, so don't let the poor performance of a locker on the street scare you off. This would be like driving everyday but being able to power out of corners hard without having the inside front spinning.
Re: Interest Thread: Wavetrac Front Differential LSD
Re: Interest Thread: Wavetrac Front Differential LSD
I'm interested as well....just not sure you'll be able to get 20 orders together. Oddly enough I'd still be interested to know what a single would be. Suppose I could ask them myself...lol
Re: Interest Thread: Wavetrac Front Differential LSD
Re: Interest Thread: Wavetrac Front Differential LSD
I don't want to mislead anyone on the price. I've edited the original ballpark.
The fellow I spoke to on the phone said it will all depend on the number of people with cash in hand.
Realistically the price will be slightly over $1000. All Wavetrac differentials include a transferable, Limited Lifetime Warranty.
The design and characteristics of the wavetrac are superior to the much loved detroit truetrac. The wavetrac never goes to open* like the truetrac does.
explained better then I ever could
Quote, originally posted by Autotech Website »
The Wavetrac® differential uses a patent pending design to improve grip in low traction conditions. Precisely engineered, converging / diverging wave profiles are placed on one side gear and its mating preload hub. As the two side gears rotate relative to each other, each wave surface climbs the other, causing them to move apart. This imparts an increased normal force through the side gears, increasing the bias ratio as a function of load. This increase occurs automatically only when conditions find it necessary, and it 'reverts' back to its nominal bias ratio quickly and seamlessly, maintaining optimal drivability and performance at all times. It's like having two differentials in one: you get the benefit of a higher bias ratio when needed without detriment to the car's handling.
I'm also exploring the possibility of retro-fitting one of their current models into the 7.2. This is not an easy task however as flange offset, carrier id/od and bearing size vary so much. The cost would likely be the same if not more to build a run of them that would work.
I'm also exploring the possibility of retro-fitting one of their current models into the 7.2. This is not an easy task however as flange offset, carrier id/od and bearing size vary so much. The cost would likely be the same if not more to build a run of them that would work.
I would imagine you would have to figure out a way to widen the entire housing. Fabricating a spacer would probably work, but the time, effort, and cost of finding a shop that could do that (assuming you can't do it yourself) not to mention all the changes to the other components - axle tube, bolt locations, CV joints makes my head spin just thinking about it.
Regardless, I'm liking this idea more and more, so put me down as a definite.
I'm really surprised there isn't more interest in this already. I thought there would be more guys wanting to take full advantage of their awd. This is nothing like a locker, so don't let the poor performance of a locker on the street scare you off. This would be like driving everyday but being able to power out of corners hard without having the inside front spinning.
I think the issue is the people with large enough budget to do this swap don't want LSD front differential. With a front and read LSD in drag racing the truck is all over the track. Some who have done front LSD have taken them out If you want to see front in action look at some of Hoovers and Hacking's Awd video's
I would imagine you would have to figure out a way to widen the entire housing. Fabricating a spacer would probably work, but the time, effort, and cost of finding a shop that could do that (assuming you can't do it yourself) not to mention all the changes to the other components - axle tube, bolt locations, CV joints makes my head spin just thinking about it.
Regardless, I'm liking this idea more and more, so put me down as a definite.
My first plunge into doing a limited slip diff up front involved a dana 30 and just as you had said implementing a case spacer. This produces a lot of challenges. When you split the case you move the pinion away from the ring gear as well. So you then need to make a ring gear spacer. In addition to these changes you need to shorten the pass axle tube and axle. If you do all this you then need to machine the 30 carrier to accommodate for a smaller bearing and get a custom set of carrier bearings/races. Still not done though. The dana 30 pinion is also different. I figured out an easy way around this however. If I'm already making a ring gear spacer I would make one hub-centric to the carrier that would also have an offset bolt pattern to run the 7.2 ring gear. Doing this would allow you to maintain the 7.2 pinion and everything that goes along with it. Even after all this the Dana 30 uses a different spline count so custom halfshafts also need to be bought/made. As you can see this is something that could be done once with a lot of trouble and would cost a lot to reproduce in any number. My goal is to do something that can be bought and enjoyed by many.
If I can get a group buy going with wavetrac I would much rather go this route. For a couple of reasons. It would be a heck of a lot easier. A lot less time consuming. More then just myself could enjoy it. The wavetrac design is superior to a true-trac. If this fails I'll be forced to going back to the above plan and one-offing it.
Click the thumbnail below to see the 2 side by side. The dana 30 is slightly larger from carrier bearing to carrier bearing.
I think the issue is the people with large enough budget to do this swap don't want LSD front differential. With a front and read LSD in drag racing the truck is all over the track. Some who have done front LSD have taken them out If you want to see front in action look at some of Hoovers and Hacking's Awd video's
This is what I was fearing. For the record no one has ever done a limited slip in one of these front differentials, that I've seen in my research. There is a handful of people who have done Lockers, not LSD's. I can see why they would take them out too as imo a locker has no place in the front end of a vehicle. Maybe for solely off road use but even then this wavetrac design would outperform it by a long shot.
This Limited Slip* Differential that could potentially be bought from Wavetrac would not have the behavior of a locker at all. This would have the manners of a subura, evo, or gtr when it comes to hard acceleration. A locker has a bias ratio of 1:1 all the time that never changes, it works well in only two conditions, straight line movement with no traction loss and when the vehicle is parked. If your truck is going to experience anything other then those two conditions then I would strongly advise against it. The Wavetrac LSD bias ratio changes constantly upon demand. When one wheel slips it transfers power to the other. I can guarantee you would never match a '60 time with an open diff or locker that this LSD unit would put up (granted your front wheels aren't in the air the entire time)
Right now for those that like to autocross their trucks when you exit a corner under hard power the inside front wheel will spin. Thus taking away not only the grip that the tire is providing in the turn but also the power the front is putting to the ground. With a LSD up front the power would be transferred to the outside wheel with the most grip and you could take full advantage of the awd in your vehicle getting onto the power much earlier on the exit of a turn.
If we can get 10 people with cash in hand that may just be enough to get a small run made.
I would really urge you guys to read up on this product. Check out some of the other group buys done on the the bmw, acura, srt, ford, audi and mercedes forums. This is very well made and performs flawlessly. Just google it and you'll see what I mean. Right now awd in these trucks is truly just 3wd. If you overpower one of the front wheels, which is especially easy in a turn, you would be better off with a 2wd truck. This is a proper differential for the front of these trucks that is capable of really taking full advantage of the awd capability we have.
Re: Interest Thread: Wavetrac Limited Slip Front Differential
Re: Interest Thread: Wavetrac Limited Slip Front Differential
It sounds VERY interesting, but $1200 for something that might have to come right back out of the truck is a little frightening. Remember the lockers were supposed to be the shit too, right up until they were tried in our trucks and damn near killed people.
If the company made one, and was able to prove in a high horsepower application in our trucks that it won't get screwy, I think I could justify the cost.
Re: Interest Thread: Wavetrac Limited Slip Front Differential
Re: Interest Thread: Wavetrac Limited Slip Front Differential
I know of 2 maybe 3 people running lockers in the front without complications. That being said, they are not autocross trucks. Not saying they couldn't be but i have never driven these trucks.
Re: Interest Thread: Wavetrac Limited Slip Front Differential
Re: Interest Thread: Wavetrac Limited Slip Front Differential
So why is it that this keeps getting compared to a locker? I'm under them impression that the LSD's and Lockers act totally different. Am I mistaken on this?
Re: Interest Thread: Wavetrac Limited Slip Front Differential
Re: Interest Thread: Wavetrac Limited Slip Front Differential
I'm a little out of my realm here....but do the Subies and Evo's along with other awd sports cars not have LSD's in the front? If not....are they running something else or just open like the SyTy's?
So why is it that this keeps getting compared to a locker? I'm under them impression that the LSD's and Lockers act totally different. Am I mistaken on this?
A locking differential or "Locker" uses a mechanism that allows left and right wheels to "lock" relative to each other and turn at the same speed regardless of which axle has traction and regardless of how little traction a slipping wheel has. In this state, the axle acts more as a "Spool". This means traction can be sent to a wheel that may be planted firmly on the ground while the other wheel of the axle is completely off the ground. In this situation an open differential will spin the free (lifted) wheel sending absolutely no torque to the wheel in the ground. A limited slip in this situation will send some torque to the wheel on the ground but possibly no enough to provide any forward momentum.
Lockers use various mechanisms to provide lock-up and can be divided into two categories, Automatic Lockers and On-Command, or selectable Lockers.
Limited Slip and positraction (posi) differentials are designed to "limit" the tendency of open differential to send power to a wheel that lacks traction and redirect the power to a degree to the other wheel of the axle. The Limited Slip and Positraction differential will send power to both wheels equally when traveling straight, however when one wheel spins due to a lack of traction, the differential will automatically provide torque to the other wheel with traction. Limited Slip and Positraction (posi) differentials limit the loss of torque to a slipping wheel through various mechanisms such as clutches, gears cones, and other methods dependant on the unit. The limited slip and positraction will not provide 100% lock up of the differential in extreme situations such as when a wheel completely looses traction. Limited Slip and Positraction (posi) differentials are recommended for daily driven vehicles and are used in many applications where traction is sometimes needed as in emergency vehicles. They are also ideal for front axles of 4x4 vehicles that are not equipped with front hubs that can be disengaged. The term "positraction" ("posi" for short) was used by General Motors years ago for their limited slip differential and has been used to refer to limited slips since.
"A limited slip in this situation will send some torque to the wheel on the ground but possibly no enough to provide any forward momentum."
^ This line here applies to LSD's like the truetrac and eaton. The wavetrac does a much better job of transferring the power to the wheel with grip. This is why it's superior in design.
420, you bring up a good point about the strength of the unit and how it hasn't been proven. The weak point in these front diffs is the pinion and halfshafts. 26 spline and such a small axle is really where our handicap is. I can't say for sure as you said it hasn't been track tested but I would be very surprised if the diff were to go before a halfshaft would.
Here is a video of an srt8 with a 9" wavetrac installed. There is a big difference between a 7.2 and 9" but it just shows wavetrac has some idea of what they are doing.
The 48 hour camaro also ran a 12 bolt wave-trac. Skip to 2 mins for that,
There is no aftermarket limited slip differential available for the 7.2. So no one is running a drop in deal. If someone is running one, it's a complete retro-fit like the dana 30 I had mentioned previously. If you want to see comparisons look at other awd vehicle running lsd's in the front. There is other factors at play, mainly the transfer case behaviour but the concept is the same.
I've stayed out of this, and intend to continue to do so. But the above statement compels me to comment:
First off, if you are spinning a front, you are spinning the rears, OR you have an OPEN V-clutch in the T-case. I feel like a broken record on this, but it's fact. You can NOT spin a front, without ALSO spinning the rears IF the T-case is functioning correctly.
Next, regarding behavior during auto-crossing, or any "road race" type activity. A very common driving technique to 'tighten the line' through a corner in a RWD car is to apply power. This works (to a degree) in a SyTy because of the 65/35 rear/front split. The rear requires LSD, of course, or the inside-rear would go up in smoke. But the front is only receiving 35% of the power. If you're driving the car smoothly, with all 4 on the ground, you're not going to spin ANY tires during a corner, as the available traction at all 4 should be more than adequate for traction in forward acceleration as well as lateral acceleration to exit the corner.
No way would I consider a front diff LSD device of any sort for auto-x work. I'd make sure my T-case was functioning correctly, and then work on my driving technique.
Carry-on. That work you did with the Dana 30 transplant is impressive.
I appreciate your input Quadrajet and you've hit on a lot of great points here.
I completely agree if you are spinning the front you are spinning the rears. I also agree if you are driving the vehicle smoothly through the corners there is no need for front lsd. However if you are driving quite aggressively and or are inexperienced and come onto the power to hard exiting a turn and go into dramatic oversteer having a limited slip front diff is going to help pull the truck forward and back into the desired line without coming off of the gas entirely. This would make the truck not only quicker to recover but also a lot more fun to drive. Could we agree on this point?
There is good reason why a lot of other awd vehicles run both front and rear lsd's. Without a doubt the transfer cases in other vehicles affect the behavior, most of the ones I've previously mentioned are truly fwd with rear assist. The principal is the same, 4 wheels driving vs 3.
I'm a bit confused about your experience with limited slips and locking hubs. You said it was a dana 44, what limited slip diff was it? I can't say I've ever seen a limited slip differential that you need to lock the hubs for. The only time I've ever seen a truck with locking hubs it was because it had a locker. I hope you don't take this as offensive, I'm just trying to learn something a bit more about the set-up.
I also agree on the subject of torque steer. If you are spinning both front wheels in one of these trucks you are going to get torque steer. That is why a locker can be such a handful, especially on the street. When you take a turn at a street light at any speed the outside wheel is spinning faster then the inside wheel and being that the wheels are locked the inside wheel is trying to slow down the outside wheel and the outside wheel is trying to speed up the inside wheel causing some very poor street manners. The same principal applies going fast through a corner which makes a locker on a road course just not an option. Something a little more relate-able like 1/4 mile, the guys making some serious power may choose a locker for the simple reason 4wd pulling instead of 3wd. Also the fact there is no other choice, it's either locker or open differential. It takes a lot of work to get a locker to launch straight in an awd vehicle. Here is a locker in action,
Now a limited slip wouldn't solve all of those problems but it certainly would help. The problem happening in the video above is both front wheels are spinning but one side of the truck is lifting more then the other. This causes the wheel with slightly more weight to pitch the truck sideways. Now that because the locker is the unit being used and the wheels are Locked and can't spin freely of one another they have a 1:1 bias ratio. The wavetrac however can alternate this bias ratio to accommodate. As I mentioned before a limited slip would definitely not solve the main problem here and that's simply more power then all 4 wheels can put down at one time. It would however help with the squirming off the line.
It seems like I'm fighting a bit of an uphill battle here because of the misconception between a locker and a limited slip differential. I can definitely understand the preconceived ill-will a lot of you have for lockers. The fact this company isn't a house-hold name like detroit or eaton doesn't help as well.
The point I'm getting at is we have 4 wheels and the ability take full advantage of it. Just about everyone puts a limited slip in the rear for the main reason of getting that power down. It's the same concept with the front. There is other mechanics in play because those wheels also steer and this is the exact reason why you don't want a locker if you plan on doing anything other then going straight. However a limited slip is the ticket to getting the absolute most out of your 4 wheels.
Re: Interest Thread: Wavetrac Limited Slip Front Differential
Re: Interest Thread: Wavetrac Limited Slip Front Differential
ahh ok, I see. I haven't had the opportunity to work on any 4wd vehicles pre 80's so that's probably why I've just never seen it before. It makes perfect sense though, thanks for explaining it.
Again I appreciate your input on the subject because to say you are knowledgeable when it comes to these trucks is an understatement.
Please don't feel like I'm intentionally trying to speak to you like an idiot in my responses. Just over-explaining so that others that may not be as well versed can follow along.
If you don't mind indulging me and we could discuss it a bit further.
Next, regarding behavior during auto-crossing, or any "road race" type activity. A very common driving technique to 'tighten the line' through a corner in a RWD car is to apply power. This works (to a degree) in a SyTy because of the 65/35 rear/front split. The rear requires LSD, of course, or the inside-rear would go up in smoke. But the front is only receiving 35% of the power. If you're driving the car smoothly, with all 4 on the ground, you're not going to spin ANY tires during a corner, as the available traction at all 4 should be more than adequate for traction in forward acceleration as well as lateral acceleration to exit the corner.
Lets talk about the 65/35 split briefly and the idea that the rears will always be spinning before the fronts. Under heavy acceleration as you know there is quite a bit of weight transfer to rear wheels. This is all dependent on the extent of the work done to the truck. Lets say we are talking about a truck with a 60/40 weight ratio. 60% of the weight of the truck is on the front tires, 40% rear. Under heavy acceleration this ratio is going to change longitudinally. Dependent on the suspension mostly. Lets say it changes from 60/40 to 45/55. In addition to this, when exiting a corner under heavy acceleration the weight ratio not only changes from front to back but also side to side. If the truck was perfectly balanced both front tires would have an equal load and both rears would have an equal load, or 50/50. Now exiting a turn this ratio may change to as much as 10/90 mostly dependent on your suspension. So now we have a front tire that has lost 15% of it's load due to acceleration and another 40% due to lateral g-force. This inner front tire now has so little load on it that it would very easily spin when the rears would still stay planted, thus causing it to lose the last bit of traction it had. If my understanding of the inner workings of the 4472 is correct, at this point the power is transferred to the rear wheels and awd in the front end is useless. Now if a limited slip was in place the tire would not spin and that 35% power would be transferred to the front outer wheel that now is taking 90% of the load laterally.
In this situation would you say that a front lsd would be warranted?
First off, if you are spinning a front, you are spinning the rears, OR you have an OPEN V-clutch in the T-case. I feel like a broken record on this, but it's fact. You can NOT spin a front, without ALSO spinning the rears IF the T-case is functioning correctly.
Re: Interest Thread: Wavetrac Limited Slip Front Differential
Re: Interest Thread: Wavetrac Limited Slip Front Differential
Dave I really appreciate your input on the subject as you can definitely provide insight into the mechanics of what's going on. Please don't feel like you need to stay out of this.
Or the auto-x scenario where weight transfer has greatly reduced the traction of a front tire. But this could ONLY happen with an open v-clutch. One that can transmit no, or very limited torque because it has failed.
In regards to this statement. Lets say the transfer case is working properly and it transfers that 35% torque the front end would normally see to the rear. The front drive components are just acting as a boat anchor in this situation. With a wavetrac in place it would transfer the power to the front outer wheel instead and take advantage of that front drive pull out of a corner.
The scenario I laid out definitely caters to the benefit of a limited slip front diff. Common mods like larger rear tires only improve the odds of the scenario however.
I want a limited slip for strictly auto slalom and road course use.
However this unit would provide a great improvement for the guys running 1/4 mile. You would have all of the traction benefits of a locker but be completely street-able.
I'm a little out of my realm here....but do the Subies and Evo's along with other awd sports cars not have LSD's in the front? If not....are they running something else or just open like the SyTy's?
Evo's got a front LSD across the line up in 2005. There center differential rate is variable and computer control, I don't know if how that affects it, but the pretty much every non LSD US Evo's don't have that active transfer case. That might be coincidence, or maybe not, I really don't know.
I am not sure about the STi, but I suspect they have LSD and I know they have a variable rate transfer case.
