I just got this from Jeff Ianitello at Engineered Performance. With the custom LSD setup (check the last pic, you can see the fricion clutches on the side gear, they are brass), it came to $700. It included a NOS late-model getrag diff (stronger, and 0 miles).

It supposedly has about 50 ft-lbs of bias torque once it wears in, but I have no way to test it ATM. I know I cannot turn the gears with my fingertips, lol. It has been discussed many times on the forum, but as fas as I could find in the archives, no one here actually has one.

I realize it looks a lot like the much cheaper "Phantom Grip" (This LSD costs $500, the Phantom Grip is $330 with "upgraded" springs), but it actually uses real clutch material to generate friction, it does not rely on the gears grinding on the diff case. Here is a thread about the problems with the Phantom Grip:
https://www.fiero.nl/forum/Forum2/HTML/082235.html

The picture below highlights the friction material I am talking about.


The website for EP is here: http://www.engineered.net/eplsd.htm

The one downside is that Jeff is pretty slow in shipping, etc. I also know he was ignoring my calls, e-mails, and voicemails when he was late. My project was nearly held up because of how long he took, but luckily it turned out ok. If you are not in a time crunch (figure at LEAST 3 months), I recommend you give him a call.

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More info at: https://www.fiero.nl/forum/Forum1/HTML/043357.html

Nice set-up and it's good to see somebody getting what they want and not trying to go the cheap route. Keep us tuned as to it's quality. Byw, I too have them on two of my N* autos.

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"Anyone can make a copy of something, it may look good, but never is the real car. Make something from your imagination, something unique, something nobody has, anything is possible and, ideas can become a reality; Archie and the Crew can make your Dreams into a reality."

Madcurl, I thought you had Phantom Grips or GR8Grips? How do you like your units, did they affect the handling at all? How well do they work and how many miles do you have on each one?

quote Originally posted by Bigfieroman: Madcurl, I thought you had Phantom Grips or GR8Grips? How do you like your units, did they affect the handling at all? How well do they work and how many miles do you have on each one?

I'm not sure of the name or if they're the same as yours? D1S installed them many years ago, but I'll ask him this week the about the name. The price was around $700 bucks or so (I do remember the bill, hehe) I've been up and down, left and right across America and so far-no issues. I have them installed on #011 and #020. I've noticed the difference on #015 since it currently doesn't have them.

Nice to see another choice out there So when are you going to test it out?

quote Originally posted by Bigfieroman: Madcurl, I thought you had Phantom Grips

I just called Kevin (he was catching a plane out of Sacramento to OKL) and he told me I have custom-made Phantom grips. D1S had the company custom make them for his applications with some type of contract (I'm guessing it contains different components?). It's an limited slip differential that allows during a turn for the inner wheel to slip or less turns vs. the outer wheel, but allows for both wheels to lock-up during straight driving, take offs, or in my case; while stuck in the snow on my way to Archie's both wheel moved vs. one being stuck in the snow.

quote Originally posted by kwagner: Nice to see another choice out there So when are you going to test it out?

Stay tuned!

quote Originally posted by Bigfieroman: Hopefully you don't have any of the troubles like the guy in the thread I mentioned. There was serious damage, I recommend a transmission fluid/filter swap, and run everything through a strainer to search for metal fragments. There would be some on the magnet in the pan, as well.

I hope not. Thanks for the heads-up and I did review the posted link you've provided and at that time I did ask Kevin about my concerns and he mentioned that several of his customers are not experiencing this problem. However, I will service my tranny later on this year, but I've clocked over 20,000 plus miles over several years- Round trip from CA to IL, CA to OK (at least three times) and CA to FL on #011 alone.

quote Originally posted by Bigfieroman: Hopefully you don't have any of the troubles like the guy in the thread I mentioned. There was serious damage, I recommend a transmission fluid/filter swap, and run everything through a strainer to search for metal fragments. There would be some on the magnet in the pan, as well.

Just my opinion, but I think that story does not truely tell what caused the failure. I've been running the Phantom Grip for a few years now, with very hard miles, and non of the failure symptoms have reared their ugly head. I believe it has more to due with having a transmission "correctly" rebuilt, and the proper choice of fluid. I have been happy with mine, does what I what it to, and does have the optional heavier spring set in it.

On a side note: It's good to see other people involved in this area, having more options is not a bad thing.

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Car History: https://www.fiero.nl/forum/Forum1/HTML/025670.html

quote Originally posted by California Kid: Just my opinion, but I think that story does not truely tell what caused the failure. I've been running the Phantom Grip for a few years now, with very hard miles, and non of the failure symptoms have reared their ugly head. I believe it has more to due with having a transmission "correctly" rebuilt, and the proper choice of fluid. I have been happy with mine, does what I what it to, and does have the optional heavier spring set in it. On a side note: It's good to see other people involved in this area, having more options is not a bad thing.

The transmission's condition would have nothing to do with differential wear and operation. Even if the diff side bearings were worn and the diff could twist in place, it would load the ring gear set and that is it. Once the power hits the differential, it has nothing to do with transmission condition. The wear in that thread was severe, and I could believe it was caused by several things. Perhaps the fluid was low, perhaps he should have been running synchromesh "friction modified" (I am, bought 6 quarts today), or perhaps the car got into some situation where the LSD action didn't work and there was a massive speed difference between the two rear wheels for a long time. I don't know, but I do know for $170 extra (I didn't have to buy the base diff at $200), I will take the EP over the PG or GR8Grip.

And regarding your situation, did you ever take your diff apart and look at it's condition? I think there is a magnet in the case of the getrag, if it is eating itself, you may have no indication from the fluid. Do you autocross or road race? I do, spinning an inside wheel is a very serious possibility.

After that thread, if I had a PG, I would split the case and take a look at the unit. There may have been some kind of cause in that thread, but you don't know it isn't the norm until you take a look.

A TH125 holding 325hp?? That is cool.

quote Originally posted by madcurl: ... it's good to see somebody getting what they want and not trying to go the cheap route.

THAT's for sure. You get what you pay for (most of the time, anyway ) I think some people would buy a tird on a bun as long as you told them it was cheap ....

quote Originally posted by Bigfieroman: It supposedly has about 50 ft-lbs of bias torque once it wears in, but I have no way to test it ATM. I know I cannot turn the gears with my fingertips, lol. It has been discussed many times on the forum, but as fas as I could find in the archives, no one here actually has one.

How significant is 50 ft-lbs of bias in a situation where the output torque to the axles is on the order of 2500-3000 ft-lbs?

Here is a post made by Will in regards to bias torque:

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"PG [Phantom Grip] has about 25 ftlbs of bias torque.
GG [GR8Grip] has about 40 ftlbs of bias torque.

Bias torque is the amount of torque is takes to turn one wheel relative to the other. An open diff has zero bias torque.
When the car's in a hard corner the inside rear tire loses grip. When you apply throttle, you can overcome the grip of the inside tire more easily than the outside tire, so the inside tire spins first. When you have a limited slip of the varieties we are discussing, the bias torque helps prevent the inside rear from spinning by holding it with respect to the outside rear tire. 40 ftlbs may not sound like much when the torque delivered to the diff is something like 2500 ftlbs in 2nd gear, but a little goes a long way. 40 ftlbs is a little bit below the threshold that induces understeer, so it should not have a negative impact on handling, other than curbing corner exit wheel spin. There's a diff for Datsuns that is spec'd for 80 ftlbs of bias torque and it requires changes to suspension tuning because it induces some understeer.

In a straight line, the friction works to curb the tendency for the first tire that breaks loose to keep spinning. It will cause you to spin both instead of just one, unless you're on a split friction surface... one wheel on gravel or ice or oil or something."

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Now, I was a little unclear as to exactly what Jeff said when I asked him about bias torque. I know he said that his normal unit has 50 lb-ft of bias torque once it wears in. He then talked about some prototype he made that induced ~90 ft lbs but it was too much for FWD. I THINK he mentioned at the end that my unit for RWD would have stiffer springs and greater bias torque, like 90 ft lbs, but I don't know for sure. I have an e-mail in to him asking about this now.

I know the unit does work, even with the wheels turned. The pic below is from his site. The 3800 SC Grand Prix floored the gas with the wheel turned significantly. There are 2 stripes curving in the turn. Now...that COULD have been faked with a RWD car with an LSD sliding the rear a bit as it did a burnout, but it looks real enough for me. We will see how well this thing works after it is installed.

quote Originally posted by Bigfieroman: The transmission's condition would have nothing to do with differential wear and operation. Even if the diff side bearings were worn and the diff could twist in place, it would load the ring gear set and that is it. Once the power hits the differential, it has nothing to do with transmission condition. And regarding your situation, did you ever take your diff apart and look at it's condition? I think there is a magnet in the case of the getrag, if it is eating itself, you may have no indication from the fluid. Do you autocross or road race? After that thread, if I had a PG, I would split the case and take a look at the unit. There may have been some kind of cause in that thread, but you don't know it isn't the norm until you take a look.

If the pin for the spider gears, and/or the spider gears are worn, it's certainly going to play a part in uneven loading when you start throwing power at it. Once something starts grinding, those fragments are going to tear up the weakest component in the link (but it doesn't me that the weakest component started it). I have a magnet plug in my case, it's checked annually, alone with a micro filter check of the fluid just to be safe. My car has been taken to road courses on occasion, I don't autocross it, but the primary reason for my setup is to spread torque load to "both half shafts", helps increase the life of half shafts. My car gets plenty of extreme conditions on the street, I didn't upgrade my drivetrain to take it easy.

Just curious if torque bias numbers you quoted from Will are with the standard or optional springs on the PG?

quote Originally posted by California Kid: If the pin for the spider gears, and/or the spider gears are worn, it's certainly going to play a part in uneven loading when you start throwing power at it. Once something starts grinding, those fragments are going to tear up the weakest component in the link (but it doesn't me that the weakest component started it). I have a magnet plug in my case, it's checked annually, alone with a micro filter check of the fluid just to be safe. My car has been taken to road courses on occasion, I don't autocross it, but the primary reason for my setup is to spread torque load to "both half shafts", helps increase the life of half shafts. My car gets plenty of extreme conditions on the street, I didn't upgrade my drivetrain to take it easy. Just curious if torque bias numbers you quoted from Will are with the standard or optional springs on the PG?

Theoretically that could cause wear, but reviewing the photos in the thread, it really doesn't seem to be the case. The pin is polished where it touches the gears, and there is a small band of wear on his pin under where the gear touches, but not where the PG touches. Given that the wear is only in a small part of the area in which the spiders contact, I would believe that the damage there is caused by a chunk of metal that got into the lube groove and was "smeared" between the gear and the shaft. There is no discernible change in diameter or anything that would denote the gears could move and **** . Also, the wear on the PG and gears appears to be extremely flat and even. I find it hard to believe that wear like that could be caused by gears that were out of place, etc. Finally, it is unlikely that preexisting wear bad enough to destroy that unit would have gone unnoticed during install of the PG. The pin would have to be out and any severe wear should have been noticeable...but nothing is certain.

I honestly don't think we can ascertain the exact cause of the failure of the unit without seeing it and doing some tests. It looks like it was just destroyed by a massive, and long, speed differential between the two wheels. The reason or circumstances around that event are unknown. With the wear the PG unit received, it is clearly much softer than the gears. That alone is a bad thing for long-term wear. Perhaps it was a multiple failure...maybe his unit was not properly heat treated?

I am not sure where Will got those numbers. I would imagine they are the upgraded springs, but I cannot say for sure.

On "spreading the torque" between the half shafts, I really cannot envision why one shaft would see more torque than the other UNLESS there was a differential speed between them, like in a one-wheel burnout. If that is what you mean, fine, but if you are talking about balancing loads day-to-day when the wheels are "in-sync" with the ground, (They are actually never "in-sync", there is a super small differential speed between the tire and the ground at all times other than when you are stopped) I really don't understand the theory.

[This message has been edited by Bigfieroman (edited 03-01-2008).]

I think those torque bias numbers might be a bit conservative.
80 lbs might be significant to an old 2040 lb Datsun 510 with 40% of the weight on the rear and the equivalent of 155 section-width tires, but on your 275 section-width gumballs on a 2800lb car with 63% of its weight on the rear, you could probably run more.

These guys suggest LSD maintenance when bias is under 100 ft-lb, and give a ballpark recommendation (which though its intended for F bodies and Chevelles, they are also RWD with about the same weight in lbs on the rear wheels) of 110-140 ft-lbs bias for streetable SCCA performance.

www.teamcanadaracing.ca/tec...t%20Positraction.pdf

If you want the phantom grip for testing or to inspect the diff or gears just let me know. If you pay for shipping, they're yours. I was using penziol syncromesh fluid, but didn't have any friction modifier in it. No documentation from phantom grip indicated the need for different fluid or addative. That wear was caused by a year of autocross and dailly driving. The only time it may have experienced prolonged one wheel spin was a 30 second doughnut. And if it was only spinning one wheel the phantom grip obviously wasn't doing a very good job of what it was supposed to be doing. POS in my opinion. The EP limited slip diff looks a hell of a lot better. When i get a limited slip for my 6 speed i'm going to go with a Quaiffe ATB differential.

30 seconds of severe wheel speed differential could have caused that. That would have given it enough time to heat WAY up and just grind the crap out of it. I am not sure that is the reason, but it could be. No thanks on the diff, I spent enough on mine already.

quote Originally posted by Bigfieroman: 30 seconds of severe wheel speed differential could have caused that. That would have given it enough time to heat WAY up and just grind the crap out of it. I am not sure that is the reason, but it could be. No thanks on the diff, I spent enough on mine already.

It just goes to show you how well the phantom grip works! If it can't even make both wheels spin in a doughnut it's pretty freakin pathetic. The only thing it's good for is burning a hole in your wallet.

I don't know for sure if it was the donut that caused that damage, but it is certainly possible. Honestly, any situation in which any LSD spins for 30 seconds would probably result in damage, but spinning only one wheel is much easier with a PG that provides little bias torque. The EP LSD is better, but not enough that there is no danger of damage. This is an issue that I and anyone else with an LSD has to be aware of. However, I don't really see long-term wheel speed differential as a common situation.

For the record, I did once do a 43 second one-wheel-burnout in an Isuzu Rodeo in the rain. Speedo pegged, top gear...it was awesome! (It didn't have an LSD, which is why the burnout started...however, I would be amazed if the side and spider gears were undamaged!)