LSD insert for handling?

[steel_3d]

I'm trying to decide if I should slap an insert in the front of my GSX, or just leave it open? Any experiences?

 

[Talon ESI-T]

What kind of insert are you speaking of? I personally have an issue with the Phantom grip because its metal on metal. I run a Retro-fit which is an insert but there is a friction material between the spydergears and the insert. Very similer action that the older muscle cars had for limited slip posi action. The only difference was that the friction material was between the spyder gears and the carrier (Sure Grip Posi-chrysler).

I see Neon Guys that claim the Phantom Grip is a god send. I have also seen them grenade a trans.

Here is some reading material that might help you make a decision: http://www.2gnt.com/nuke/modules.php?name=Sections&op=viewarticle&artid=67

Terry

 

[jtmcinder]

For handling? Absolutely not. Inserts are two-way, so it will hurt turn-in as much as it helps corner-exit. Add in the potential to take out your entire transmission and it's a no-way.

Leave it open until you can get a helical. Heck, maybe leave it open forever and learn to drive like Tevenor.

- Jtoby

 

[FORMONTOYA]

I run the SBR inserts in my car. I will say that straight line acceleration is improved as well as corner exit. But will definitely agree that corner entry/turn-in is not as stable/controllable as I would prefer, but doable, and to me (in no way am I as knowledgeable or experienced as jtmcinder) they seem better than an OEM diff.

If you're looking to have a little fun and don't go over about 300-350WHP they work good. However, if you're truly looking for competitive times (drag or course), I agree........put the $200 toward a true LSD.

LSD inserts verses a true LSD is definitely an item that requires you to be honest with yourself and your goals to avoid spending extra cash in the wrong area.

My car has NOT seen a 1/8 or 1/4 mile track since the day I purchased it back in Nov 97. It sees on average 3-5 autocross days a year, the rest is just normal "street" driving......so that gives you an idea of what my "opinion" is based on. They have been in the car since Dec 05 (about 4K miles) with no issues so far, but then again, you can see I'm not very hard on the car.

 

[pneumo]

I REALLY like having a Quaife front diff in my AWD car. I'm constantly amazed at how early I can get back on the gas, and how hard the car exits corners with it.

 

[steel_3d]

Alright, thanks for the info! I wasn't sure how much it would hurt corner entry. But since I'm awd I should be decent on corner exit so it's probably not a worthwhile tradeoff.

 

[jtmcinder]

It hurts entry because it's two-way: it always resists allowing the wheels to turn at different speeds. At entry, you want an open front.

The only people who should consider an insert for handling are those with FWD and not enough $$$ for helicals. In their case, the ability to put down anything at exit outweighs the cost at entry. The rest of us just need to remember that the go pedal is not an on/off switch ... at least, until we get helicals.

- Jtoby

 

[mavisky]

I've got the phantom grip and while I agree with Jtoby that the exit performance outweighs the entry speed I still say its not worth it because my Phantom Slip rarely does much of anything for me. I absolutely hate it and wish I'd not spent the money on it and applied it to a better suspension setup or a better lsd. Hopefully once I get a job that pays me in money instead of internet time I'll be able to afford a nice Quaife for the car.

 

[steel_3d]

Have you tried using different oils or additives? I know some people recommend the mopar moly-slip lsd additive for our trannies in general (found at the dealership). Might change the properties of the oil enough to give the phantomslip some grip... You could also maybe swap the springs for some heavier ones.

 

[jtmcinder]

You could also maybe swap the springs for some heavier ones.

Right. It's all about pre-load on those things. If you aren't fighting at turn-in, it's too loose to help at exit.

But saving up and doing it once and doing it right is always a better plan.

- Jtoby

 

[mavisky]

I've tried different oils and the diff likes Wal-Mart 80-90 the best for some reason. Probably because it's the worst at actually lubricating things.

The springs that are in it are the strongest set that phantom grip makes for our application. I spent a good amount of time on the line with tech support at Phantom Grip. Their best line ever was when they told me that due to the extra thickness of each coil on the new "race springs" the lsd insert couldn't be compressed as far as before so I'd have to grind down my spider gears on a bench grinder to get the unit to fit. I'm not joking, that's almost word for word what they told me. I said "F that" and proceeded to take a millimeter or two off of each block of the insert to make it fit instead as I really didn't feel like making my already fragile diff any more fragile.

 

[jtmcinder]

Oh, com'on. Everyone knows that the pinion-gears inside all DSM differentials are over-engineered and indestructable, so go right ahead and grind them down as much as you want.

Idiots.

What's next? A patented one-spider diff to reduce rotating mass?

- Jtoby

 

[Rick@AP]

Help the handling school drop out here.

Are you saying that a 1.5 way diff is better than a 2 way for an AWD?

 

[jtmcinder]

On tarmac, absolutely. In fact, if Cusco would make a true 1-way for DSMs, that might be a good option for the front, instead of a helical. In the rear, a 1.5-way is fine, as it helps keep the back of the car from passing the front. But in the front on dry pavement, nothing beats the turn-in of an open diff.

- Jtoby

 

[mavisky]

mmm, cusco one way. I'd like that alot. Right now it's either Quaife or Kaaz for us 1g guys.

 

[steel_3d]

Ok, so corner entry you want a 1-way or open diff, that's all fine and dandy.

But now I'm confused about corner exit. Is there an ideal solution here for the front? A locked-up diff of any type would try to keep the inside wheel spinning as fast as the outside, breaking traction and causing understeer and/or torque steer. Maybe not as extreme as an open diff spinning the inside front, making it a net gain? Even a torsen is fully locked up if you mash it exiting a turn, right?

It seems an open diff might be ideal at distributing torque on corner exit, since it lets both wheels spin at their preferred speed, up until you break traction (which might be a decent ceiling on an awd)... Or does it have issues with torque steer, which gives the edge to the torsen even before you break traction?

Let me put it another way. Does anyone have a problem racing awd dsm's with an open front diff, and is there a solution for it? I'm looking at about 400awhp.

 

[Tevenor]

With an open diff, you better know how to squeeze the throttle on corner exits instead of mashing. You will constantly be floating on the edge of traction vs grip until you can straighten out the wheels. And if you have enough torque ( which translates to really mean you don't have enough tire ), you will spin them even as you straighten out. Entries become a measure of cajones, exits a measure of patience.

That being said, I would be very happy with a 1-way setup.

 

[nightspeed87]

dont the awd guys just weld the dif instead of getting lsds. My friend welded his and his car doesnt like to turn very much but his tires get more of a equal distribution of power too, limiting slippage. ( of course this is more for the straight line guys )

 

[1LE]

It seems an open diff might be ideal at distributing torque on corner exit, since it lets both wheels spin at their preferred speed, up until you break traction (which might be a decent ceiling on an awd)... Or does it have issues with torque steer, which gives the edge to the torsen even before you break traction?

Let me put it another way. Does anyone have a problem racing awd dsm's with an open front diff, and is there a solution for it? I'm looking at about 400awhp.

Yeah, with an open front diff and only 400hp at the crank on a 2g (low to mid 300's at the wheels) the front end jumps all over the place with the stock open front diff. With a Quaife front and center, the car rockets forward in a straight line on any surface (only problem areas being when there just isn't enough traction and all 4 spin). Absolutely HAULS out of corners that it used to understeer out of like crazy. Turn-in is unaffected. Stopping feels a little straighter, but that doesn't make a whole lot of sense given how a Quaife works. Perhaps it's just the confidence of knowing the car will go straight once I lay on the power.

 

[mavisky]

dont the awd guys just weld the dif instead of getting lsds. My friend welded his and his car doesnt like to turn very much but his tires get more of a equal distribution of power too, limiting slippage. ( of course this is more for the straight line guys )

Welding diffs is great if all you care about is drag racing, but as was mentioned in the title of this thread we're concerned with handling.

The car will turn way worse than before if you weld the center diff in an awd dsm.