i don't know people are saying replacing the front isn't a big deal. Going from memory based on my upgrade a few years ago, but I remember going with the Wavetrac for two reasons. 1. was a lifetime warranty; and i mean no questions asked. Mine broke, and both us and Wavetrac think it was during install, but they still warrantied it to find out how it broke, because they said I was the first to break one (lol). 2nd reason, was that I believe it is the only front diff that when one of the tires lifts off the ground, it will NOT send "all" the power to the lifted wheel. I was still RallyXing my car when I did this mod.

Also, so as to stay reasonably on topic, I did a TRE Maxlock recently, and am about to try it out in the coming weeks. I am very excited for both autoX and for drag. My stock rear diff was so worn out it was just open.

 

Could you please say more? We're interested!

Conventional wisdom leads one to believe that going to a 1-way clutch type front diff is going to make the car understeer and try to straighten out on throttle. 1.5/2-way should increase understeer under braking too.

My understanding is that a helical will bias the torque to the higher traction wheel until it exceeds the bias ratio, at which point it "goes open". Not all helicals are the same as the TBR (torque bias ratio) can be tuned thru gear geometry. It'd be interesting to know the differences between the OEM RS, Quafe, and Wavetrac.

Here's the tech sales shpiel from Wavetrac:
http://www.wavetrac.net/technical.htm

 

Did you restack your OEM diff before getting the Maxxlock?
Can you elaborate on the differences with the Maxxlock?
What's your suspension set-up, tires, power?

 

What are the track conditions you're driving? Tight and slow speeds?
What are your alignment settings? Do you have a crazy amount of toe-out?
Is the car pushing super hard - too much slip angle?

If the diff is broken you'd know 'cuz there'd be chunks loose. Otherwise they don't really wear out and therefore the issue is likely elsewhere, and cheaper.

 

just threw in the Weir 12 plate and topped it up with straight Diaqueen LSD gear oil. I was expecting "clunks" at low speeds but i'm getting "clicks" at all speeds when the wheel is turned 1/8th turn either direction instead. is that normal? I could also feel the rear diff bind a tiny bit at low speed U turns sometimes which I believe is perfectly normal.

took it for a drive and I managed to coax the tail to come out on throttle at a low speed 90 degree corner where it required almost 1/2 turn opposite lock to straighten out. not quite RWD territory but no more pushing and goes where you want it to. hasn't tried to kill me like my MR2s do anyway

will report findings after the time attack on the 25th at a track where the car used to understeer terribly on throttle once the inner rear wheel comes off the ground.

 

Looks like you drive a IX. Have you done the ACD reflash? If not you will only really get the rear active at higher throttle amounts. These two mods add up to a higher sum than the individual contributions by a great deal.

 

I will have a full writeup coming in the near future, I promise. I would like to get some videos up as well. So far I've been to 3 autox events since the new diff. My next one in in 3 weeks but I keep saying that I will do a full review when I get a chance.

Sparknotes version: It is everything people on here say it is. Point the wheel and mash the gas and the car will point itself to that line. The push is now eliminated.

My setup consists of:

~400AWHP/400AWTQ
255/40-17 Z1 Star Specs mounted on 17x9.5 +38 NT03
Bilsteins Robispec Springs Ciro Design Camber/Caster Plates
Perrin RSB and endlinks on softest setting
Stock Modded FSB
TRE Maxxlock Rear Diff with all the goods
ES Mustache Bar and Carrier Bushings
Camber -3F -1.8R
Caster 5.2L 5.2R
Toe 0 all around

AS I said though I promise I will give a full review when I get a chance

 

Ask yourself this - if, as you propose, a clutch type in 1 or 1.5 way would make the car understeer, why would rally cars run them if they are in an almost constant state of oversteer? I propose that what you call "conventional wisdom" is wrong. From where did you get this wisdom? (just curious, I'm always up for reading and learning more)

With your torque biasing thought train I think you are right - the problem is that the torque bias can be overwhelmed pretty easily in a decent track EVO running R-comp tires. I don't know the numbers exactly, but let's say the Tq bias is 4:1 for a given front diff. You take a corner and the car rolls and the outside tire now has 2000# of weight/grip on it and the inside tire has 200#. You have exceeded the Tq bias (now 10:1) and the diff is now for all intents and purposes an open diff. The only way to make it active again is to increase the grip of the inside tire relative to the outside tire (reduce weight transfer by lowering CG) or add some "preload" to it. This is how Wavetrac works better than a Quaife or Mitsu front diff (which I believe you will NOT be able to tell a difference between) if my info is correct. They add some springs in the Wavetrac diff to add preload so to extend the useable torque biasing range. . . a slight mesh of the torque biasing and the clutch pack style diffs if you will. Now this is all just my understanding - I'm not a drivetrain engineer and have not studied the Wavetrac in depth.

I believe you are mistaken.

Wavetrac may have a great warranty even though it broke. That I don't know about. What you are wrong on is stating that it is the only diff that does NOT act as "open" if one of the tires has no traction (off the ground or on ice). This I believe is incorrect.

The Wavetrac I believe is better than other helical style diffs such as the OEM Mitsu and the Quaife, but it does NOT compare to the clutch pack style diffs. Just like in the clutchpack style rear diff be it a TRE Maxlock, restacked OEM, Cusco, etc - if one wheel is completely off the ground all the clutch discs are engaged transferring the power to the wheel with traction. At least that's the way I understand it.

 

^ my only input to this is that i think a 1.5 in the front would increase understeer - simply because there is some lockup on decel, which you probably will be doing on turn in, and any lockup between the two wheels will have a small amount of resistance if the speeds between the wheels change - which happens in cornering. that's my simple understanding of it. same thing applies to adding preload to any diff. 1 way is typically the recommended setup for front lsd's, probably for that reason. (i could be wrong on all of this). the exchange of 1.5 way would be more straightline stability, i.e. during braking

also, i think for rally cars, they would prefer their cars to be setup to understeer - i wouldn't want to put a loose car on a loose surface, but that's just me. aren't most racecars (race car race cars, like f1, le mans, etc) setup to understeer pretty heavily? (no idea)

 

Anyone have any video of what the rear diff sounds like when it gets noisy?

Either I'm doing it wrong, I've got a bogus rear diff or mine is quiet... I never experienced any chatter or rear diff noise with mine. It's been correctly broken in as per instructions on the TRE site and I think the last fluid change was less than 1,000 miles ago.



I've got the TRE 12 plate MAX LOCK

 

TRE's seems to be fairly quiet - also seems to depend on the fluid you use, break-in, etc. My Cusco sends violent bangs through the car for parking lot speed turning

 

 

My TRE MaxxLock makes a lot of noise while making tight turns such as a 3 point turn. It sounds like a binding noise and I would be concerned about it but I honestly just attribute it to the fact that it has much more lockup.

Im using Amsoil Severe Gear 75-110 right now. Well its more like a mix of 75-90 and 75-110 right now. No friction modifiers or additional cocktail to quiet it up.

 

Huh. Interesting. I'll have to try the three point turn. I've ran a few road race events on it and I haven't noticed anything out of the ordinary.

I'm running Redline 80W140 GL-5 atm...

 

Yeah anytime I am going really slow in a parking lot and cut the wheel tight it shakes violently. Jon said I would experience some noise but itll calm down.

I didnt do any figure 8's or anything like that to try and break it in quicker.