im looking into some lsd units for my gst since i should be making over 500whp this summer.

Was wondering if any of you have tried the rtm lsd unit?

https://www.rtmracing.com/xcart/product.php?productid=16815&cat=818&page=1

if not im also considering the quiafe lsd rtm is also offering.

any thoughts or opinions are welcome!

Check your PM

I installed one of these RTM LSD units in a customers transmission last year. Fit was perfect and looks like it will work well, however these are hit and miss from the research I have done. Since there is no thrust bearing between the LSD unit and the spider gears, over time wear can cause pieces of metal to break off and damage the transmission.

Though I have personally never seen one of these LSD units damage a transmission, I would consider a proper LSD like a Quaife, unless you are on a poor man's budget.

Will the RTM unit work as intended: yes it will.

My TRE tranny came with a RipGrip front diff, same as above.

http://www.teamrip.com/RIPGRIP_DIFF_AWD.htm


No complaints, has worked well for me on my AWD.

I also have a trans cooler with pump and inline filter, so that may help if the wear Reza mentioned occurs.

Like most things, you get what you pay for. Do you really expect a $225 insert to work the same as a $1000+ true LSD? Sure the insert will probably help but it won't perform like the real thing. I would think just installing an insert would still leave the stock diff prone to explode with wheel hop? (real LSD like the Quife should prevent this).

My thoughts are, if you plan to make 500+whp, why are you looking at such a cheap solution for the item that puts the power down?

My car was fwd, I ran a Quaife. Last time I had it dyno'd in street trim it made 410whp/352ft/lbs. Having first hand experience with a 400whp+ fwd, my advise would be skip the LSD & swap to awd. The car is so much better in awd form & from experience I would never build a high hp fwd again.

What about welding the front diff? Has anyone here tried that? (assuming the car was more a weekend warior/track car)

Apart from "Dont do it, its bad", does anyone have any real world experience? If his car is gonna be a weekend/track car at that power level, might be worth just welding it until he does an AWD swap.

i didnt expect it to work the same, im just trying to weight out my options and see what others have experienced with the products.

ive also been thinking about the awd option,but ive enjoyed my car more from roll racing and 1/2 mile applications than 1/4 mile from a dig; hence the lsd option.

thx for sharing from your experience though =) i appreciate it.

i still daily the car during summer time stephan haha. welding the diff wouldnt work.

I've used the inserts in a fwd for 8yrs with no problems. My car did mostly spin both wheels in a strait line but I wanted to make sure as I frequent Shannonville. With the insert even cornering under power was different as the car wanted to push to the outside instead of one-wheel-peel. The original insert was replaced 2yrs ago when a shift fork broke, mostly as I felt the springs had lost some tension as it may have been used when installed. It was replaced with RTM's version and it works as advertised.

What do you want the LSD to do? Grip around corners or just for drag?

Actually, I would still give the same advise for your application as well. My car was never set up as a drag car & I actually use to drag race it more when it was a fwd. I've had the awd swap done for 7 years or so & have only been drag racing twice since. If I go to the track now, its to turn corners.

My cars mainly a summer daily with some lapping use & for this, I would recommend the swap over an LSD any day. Even daily driving a high hp awd is so much more enjoyable then fwd.

I really think you AWD guys need to get a Cusco tarmac:
http://www.cusco.co.jp/en/parts_product/products/tarmac_gear.html

With this in my tranny I didn't find a need to install my front Mitsu LSD anymore, in fact I just sold it

You guys should be running center LSD's so quit being cheap DSMers and get the Cusco tarmac

I thought those are nearly impossible to get anymore though.

Where did you pick yours up?

I have had it for around 10 years. Installed it a few years back when I built my trans.

Ya they don't make them anymore. I've be on the hunt for along time for a good condition one.

Also Reza, You sure you have a tarmac? I do remember you saying your Cusco was a clutch LSD? Cusco made the open split tramac diff and also made a 50/50 split clutch LSD unit similar to the Kaaz center diff.

The problem with a cusco center diff is it is still an open diff. Its not an LSD. It says it right in the description link you gave!

"You can do the Side-turn, with the parking brake, as it does not have the Center LSD function.
･Watch out!: This product is not Limited Slip Differential Gears."


Its not going to help traction (and i mean traction around a corner, coming in or out of it). Its only helping with rotation of the car by biasing the torque split.

Our best option is getting a quaife and trying to keep it together as its well known that they fail because the housing thickness is thin. It has infinite lockup so it will be progressive at transferring power to front or rear.

My car is staying all stock diffs for the sake of getting it out this year or else it would have an EVO rear with a quaife center and a 1way front LSD. The evo rear and quaife center sitting in boxes ready to go.

Sorry Mike, should have mentioned I have an older style stronger Cusco center LSD made back in the days. It does not look like your regular Cusco tarmac and I doubt you'll ever find the same one I am using.

It is 4 spider, it is not open, and has clutch pack LSD in it. I get instant power to the rear wheels and do not fry the front wheels like the open center. Car over steers well too. On my car this diff has made a night and day difference and helps with traction tremendously! My car handles more evo like with this diff.

I wasn't aware the Cusco were no longer made so I guess your only option is the Quaife, which as you mentioned can pretty much take out your intermediate shaft.

Either way if I was to choose between a front LSD or a center, I'd go with a center. Like I said I just got rid of my Mitsu clutch pack front LSD as I feel it was no longer needed. With just a front LSD all you are going to do it fry both the front wheels if your making serious power. I'd rather a shift of power to the rear than just a front LSD and open center.

Obviously I am more setup for drag, so I would only really need the front LSD if I were flying around corners which I don't do on the street or drag strip.

So IMO, if you plan on lapping like the 2% of members here, get a front LSD. If your car is more of a street and drag setup, get a center LSD. If your rich and have deep pockets, get all the LSD's. If your feel that your DSM is cheap enough to just get an LSD insert, go for it Last thing I want to do is recommend an $1800 diff for someone with a DSM worth only $800

Also would be nice to hear from someone who actually has a front and center LSD, and real world experience driving with these in a DSM. I mean Mike your opinions are great and everything on paper, but they just don't count yet as you have not been able to get a DSM running in the last decade

Scott?

Want to know something frustrating. I speak to Dennis Grant about setup and he says Quaife front, quaife center, viscous rear with a stock rear bar is the way to go on a 2g! He says set the car up to grip in the front as much as possible and to treat it like a FWD but dont try to ungrip the rear!

Complete opposite of whats written all over the internet and essential what most lapping guys have done.

The problem with a clutch pack LSD is its only slipping for a short period of time before the plates lock and now acts as a solid 50:50 split (aka welded diff). Yes this would help straight line traction. You really want a hydraulic pressure controlled diff ala EVO 4-10 and subarus. Let the computer control the lock up. Not the ramp angle of the diff.

Still does not explain all the Quaife failures that people have had over the years. I'd rather run a regular 4 spider than take chances on destroying my trans.

A quick google search and I found this quote from TRE:

"Hello everyone -

This is Jon Ripple of T.R.E.

I rarely make posts here but I'd like to clarify some things.

Last winter we noticed that people were breaking their Quaife center diffs.
We found that the backlash between the center diff and intermediate shaft is
a little excessive. This will cause gear tooth breakage if and when the
gears are heavily loaded. I've contacted Quaife USA and UK and explained to
them why their diff is breaking. The backlash issue is the major problem
followed by the heat treating. I discussed this problem with Mike W @ RRE
and he talked Quaife USA into sending some DSM parts back to Quaife UK so
they could see if anything wasn't to spec. After a while Quaife stated that
yes there is some backlash but they have to leave it because they do not
final grind the tooth profile after heat treating, leaving any distortion
from the heat treating process. To allow for this distortion Quaife has
elected to ride close to the acceptable limits for backlash. This will cause
variances and the end result is some gear noise. Some of you may notice
that after you've installed a Quaife you will here some gear whine,
especially in 3rd gear - no load. This is the backlash issue.

What is my conclusion? If you launch your Mitsubishi AWD hard enough the
Quaife center diff will eventually loose some teeth. Sorry guys but the
teeth on your stock center diff are stronger. I've been in a lot of DSM
gearboxes and rarely do I see busted teeth on the factory center diff gear.
Pruven Performance has cut several mean 1.32sec 60' times with the
transmission that I built for them without any breakage. That is a full
season without any breakage. That trans has the factory center diff with
the spool that we sell.

The size of the planetary gearset inside the Quaife center diff is a little
small for the power that a built 4G6x can belt out. The thrust/friction
surface of the sun takes a fierce beating. Quaife could remedy this by
reducing the combined thrust/friction surface area of the planets, allowing
them to wear evenly with the sun's thrust/friction area. This will also
provide the Quaife with improved Auto-Torque-Biasing.

I do not feel that I'm dogging Quaife. Overall they built the best limited
slip differentials. I like the ATB (Auto-Torque-Biasing) action of the
Quaife because it will send equal power to the front and rear diff when you
launch hard. However I prefer the 4 spider center diff from Speed Design
that we sell. It is well built and holds up the best for the money. If
the car only spends time at the strip then the Spool will work the best in
this application. More info on transmission upgrades can be found here,
http://www.teamrip.com/awd.html"

Quaifes fail. Its a known problem. Racing breaks parts. Thats known as well. Maybe in a 350-400hp car they will survive without launching. I'm going to take the risk. Yes when my car runs. IT doesn't move yet!

Tim Zimmer took a quaife and had it REM treated for me for that extra insurance.

DG replaced his every 80 launches in anticipation of it breaking.

Pay to Play!

Not sure if the REM process would help with the excessive backlash, but it should definitely toughen up the teeth some. Did he REM treat the intermediate shaft as well?

Since you won't be launching the car much, hopefully it'll hold up!

Mike why hold out on putting the diffs in? Your going to hate the car on stock diffs. Doesn't take long to at least put in the Evo rear.

And make the car handle like a FWD? That's the stupidest sh!t I've heard from you. No one wants a car to handle like a FWD not even guys who track FWD's....

That's a good read posted by John, thanks Reza.

I installed a quaife centre this pass season. And got that whine. I thought I shimmed something improperly, but that kind of makes me feel better knowing it is normal. Not good, but normal.

I threw my car together with an Evo geatset, stock clutch and turbo, and there was no way the tires were breaking loose on a launch. In fact I couldn't even launch the car.
The clutch would burn before I would loose traction off the line.

However this was also my first year turning corners with my car and on the 180 turn at the Shootout my one front tire would always light up when accelerating out of the corner. Super annoying. Especially in a car barely making 300hp at the time and 245 tires all the way around.

We will see what this year brings. but I would love a front lsd in there...

I plan on tearing down the Trans to check things out, I'll report back if the quaife took a dump.

can someone tag this post?...please!

Guess i should have wrote, Setup like a front wheel drive not handle like a FWD.

Its odd thinking i know and its hard to grasp. Were all putting diffs in to lock the rear along with big bars to get the back end to break loose while his saying keep the back end gripped and and add more grip to the front and steer with power.

Power on oversteer scares me!

No i did not get the intermediate shaft done. This quaife will go into the 2g trans you originally build for Rob.

Yes right, sorry I lost track of all the trannies I have built.

I've driven a good friends fairly powerful GST(built motor, FP Red, 30psi on pump gas) with a TRE build trans with a Wavetrac LSD, it was quite different from my days as a fwd. Car pulled nice and straight, didn't notice any torque steer really.

He went with the Wavetrac as I believe it was TRE that told him he wouldn't break it where as they wouldn't guarantee his trans work with a Quaife in it.

He's been abusing his car for the last 3-4 years with this LSD and hasn't had a single issue with it. I'd definitely check it out.