Completed the 8.8 diff swap yesterday at ILLS. Long day with the custom fabricated pinion brace talking up alot of it. Everything fell into place as planned. I'm doing my best to break them in slow but after some break in by Robs and a slow ride home last night, I've slammed it down a few times today. First gear is gone quick, second too. I found myself very surprized how quick 60 comes, its very noticeable...VERY noticeable.


Thanks Rob for the help. Your welding and fabrication skills made it alot easier than it could have been. I owe ya.

Completed the 8.8 diff swap yesterday at ILLS. Long day with the custom fabricated pinion brace talking up alot of it. Everything fell into place as planned. I'm doing my best to break them in slow but after some break in by Robs and a slow ride home last night, I've slammed it down a few times today. First gear is gone quick, second too. I found myself very surprized how quick 60 comes, its very noticeable...VERY noticeable.


Thanks Rob for the help. Your welding and fabrication skills made it alot easier than it could have been. I owe ya.



It was a fun project for sure. I have done allot of custom vehicle projects before and no matter how well things are planned out there still are some minor glitches along the way. It is just the way custom jobs work. I cannot really think of anything that didn't go as planned yesterday.

I want to see that thing on the track with that new 8.8" LSD and the 4.10's in the rear. It looks like next spring GLD will be in store to see a few sleepers running at the track.

By the way, you can pay me back in beer one of these days. ;) I will not mention what quantity it will take though. :D

wtf, did you 2 plan to synchronize you big unveiling's together, good job to you both, how about some pics 02asdfghjkl;

wtf, did you 2 plan to synchronize you big unveiling's together, good job to you both, how about some pics 02asdfghjkl;

I will neither confirm nor deny that rumor. ;)

The vagueness is staggering here. Make with the pics and info...stat!

Here's a few.

My original brace design that I drew up several months back ended up being pretty close to what did work well. I have to still tweak the exhaust a little to the right, it always hung to far left, this is a good reason to correct it as its real close to the brace on the right side.

The diff cover was a extra I picked up and scraping the undercoating off wasn't a priority. Notice the 8.0...sneaky hey.

I'm going to pull the brace over the winter so Weld Master Rob can close up the open ends and its getting powder coated for the finished look.

The vagueness is staggering here. Make with the pics and info...stat!

Its been discussed in other threads in pretty good detail before, sorry for the vagueness.

Basically in my quest to go where no man has gone before, gearing and LSDing the LS. I came to this as the easiest way.

Its a MarkVIII diff fitted with the stock Gen1 LS cover. Custom pinion brace for front mounting. And a modified driveshaft.

Fitting 8.8 guts into the stock LS case I believe to have pinion fitment issues. I started with this concept as it has been discussed as possible but never completed. Also with the unique pinion design of the LS and its driveshaft, if you took this approach you would still have to modify the driveshaft. I found myself laying under my MarkVIII and my LS several times and imediately found the cover pattern to match. This led to discovering the width is almost near identical. Front mounting was never a real concern because while a little different, I saw ways to make it work. Axle bearings and seals were found to be same part #s and eventually between ILLS and myself collecting a few extra diffs and axles we confirmed axle fitment to be tha same and confirmed cover fitment with out ever tearing down our cars. I had one built, got the shaft modified, collected the rest of the parts and bolt in day happened yesterday and I have all my stock for a swap back if i desire.



Oh yeah GEN1...GEN2 will require GEN1 axles at the least. I think thats all but not positive.

Good stuff, dudes!

Oh yeah GEN1...GEN2 will require GEN1 axles at the least. I think thats all but not positive.

We will find out...

We will find out...

Yes we will.

To clarify Gen2 owners will need a Gen1 diff cover and Gen1 axles at least. We think this is all.

You gents are goooood. Impressive showing on this and ILLS's turbo project. The efforts and the simultaneous unveilings are music to my midwestern ears.

I've been effectively stalking this forum for a while now and just picked up my '04 LSE a few months back. Pleased to see that both ILLS and 02LSE96(...and some change) are near by. I may learn a few things along the way at GLD.

Thanks for blazing these two trails!

What did you end up having to set the pinion angle at?

What did you end up having to set the pinion angle at?

The old diff was measured for angle/position in the car before removel. The new one was fabbed to be in the same place. The length of the 8.8 unit is longer than the 8.0, but the flnge on the 8.8 is shorter. Not much difference at all really and the way the diff is mounted on the front up/down adjusting would be easy.

Thanks for giving new dimensions of performance changes.

Thanks for giving new dimensions of performance changes.




Sometimes if there is no road to where you want to go you have to pave your own way. :cool:

Can't wait to see a video. Next spring you two are gonna run each other...right?

Can't wait to see a video. Next spring you two are gonna run each other...right?

Definately.

Definately.

*cough cough* spring meet :D

Deedeedee! I was gonna ask a question here and then I read the answer my damn self... :shifty:

much props guys

What is the easiest way to get LSD of any kind into 1st Gen LS?
Maybe with same gear ratio or slightly taller.

What is the easiest way to get LSD of any kind into 1st Gen LS?
Maybe with same gear ratio or slightly taller.

I would look at it this way.


If you want a little more gear just get a 3.58 stock unit and swap it in. You won't have the LSD but these cars hardly need it. This will go right in without problem and done for cheap.

If you want a little more gear and LSD the possiblity to install a 8.8 LSD unit into the stock LS diff does look like a possibility but you will have to retain the LS ring and pinion. So then you will have at most a 3.58 with LSD. This will cost some more with the cost of the traction lock and labor to install. Or maybe the kind of LSD that doesn't require removing the ring and pinion. This is a possibilty that may work but never done. Just looking at the carrier insides it looks like a possibility.

If you want more gear swapping to the 8.8 center section as I did seems to be the only way. This costs a fair amount, I'm $1250 in without the cost to fab the front mounting brace.

If your desire is 3.73s I would say its a waste of time since its barely more gear than the 3.58s and for the extra money...not worth it.

Nice thing with the 8.8 unit is there is so much available gear wise 3.90, 4.10, 4.30, 4.56! All kinds of traction devices. And of coarse its stronger.

Mine is making a howling noise, for lack of better description, from the rear. The oil is there. It gets noticeable from 35MPH and louder the faster the car goes.
I might as well upgrade it so I am looking at options. I know that none of the shops will take LS seriously so I gotta do the research by myself and just tell them to do it.
I mean, even "car guys" think LS has air suspension and is FWD so...

If you want a little more gear and LSD the possiblity to install a 8.8 LSD unit into the stock LS diff does look like a possibility but you will have to retain the LS ring and pinion.



Jason I would refrain from saying this if I were you. No real measurements have been taken so at this point in time it is just theory. People take things too literally on forums and may read way too much into that comment and interpret it as "It is doable." which has not been confirmed yet.

Jason I would refrain from saying this if I were you. No real measurements have been taken so at this point in time it is just theory. People take things too literally on forums and may read way too much into that comment and interpret it as "It is doable." which has not been confirmed yet.

I said it was a "posibility" and "never done". If someone takes that as gold to find out and it don't work and blames me....they're the dummy.

If a person was capable of setting up there own ring and pinion they would only be out $200-$225 for the FRPP Traction Lock, could resell if didn't work. Actually a used one can be had for alot less tested and rebuilt if found to work.

Also Quik seems to have this set up started already. I PMed him on if he had a entire 8.8 guts in the stock LS diff or was it a 8.8 unit with the stock 8.0 ring and pinion fitted into the stock LS diff. He didn't know or want to tell me. Anyways if the bearing and main caps fit thats a good start but yes it hasn't been all figured out yet.

What do I care...I'm set already:D.

It seems to me like I'm better of just getting a faster car than trying to make an LS faster.
Although, maybe by THAT time, there will be more details on the turbo and SC to get more power out of a great car that LS is and I could pick 06 LS.
The reason the Quik won't provide much details, at least about the differential, is that it IS an LLSOC.com project. Maybe they don't want to pass up info to a free forum, since if I remember correctly it was a freebie from another member that abandoned the project. Correct me if I am wrong. I just assume things.

How much mileage changed in the LS with the higher gears?
Either the 4.10 or the open 3.58 from early LSes.

I said it was a "posibility" and "never done". If someone takes that as gold to find out and it don't work and blames me....they're the dummy.

Also Quik seems to have this set up started already. I PMed him on if he had a entire 8.8 guts in the stock LS diff or was it a 8.8 unit with the stock 8.0 ring and pinion fitted into the stock LS diff. He didn't know or want to tell me. Anyways if the bearing and main caps fit thats a good start but yes it hasn't been all figured out yet.

What do I care...I'm set already:D.


Jason you are basing that statement upon a friggin 10 second eyeball measurement in my garage, with no side by side teardown performed on the diff's. If there were more preliminary "real" measurements taken then I could see you stating what you said. Until I tear both diff's down and take detailed measurements with my machinist calipers it is all just bench racing for the moment. Don't put the cart before the horse on this one no matter how promising it initially appears.

I do not exactly trust what that fella said regarding things that were accomplished with that rear diff of his. I would take what the guy said for a grain of salt until there is really any solid results from this either on his end or another. Two and a half years for a mere custom supercharger project does not bode well for proving a person has what it takes to follow through with projects.

It seems to me like I'm better of just getting a faster car than trying to make an LS faster.
Although, maybe by THAT time, there will be more details on the turbo and SC to get more power out of a great car that LS is and I could pick 06 LS.
The reason the Quik won't provide much details, at least about the differential, is that it IS an LLSOC.com project. Maybe they don't want to pass up info to a free forum, since if I remember correctly it was a freebie from another member that abandoned the project. Correct me if I am wrong. I just assume things.

How much mileage changed in the LS with the higher gears?
Either the 4.10 or the open 3.58 from early LSes.

3.58s would likely make no noticeable difference. 4.10s I'm expecting to see the highway to do down, city to stay the same if not go up a smidge. Overall I'm expecting the average to drop a few.

Quik posted pics on here so I asked a single question and didn't get the answer. I think I know why that project stopped, but just a assumption.

Although, maybe by THAT time, there will be more details on the turbo and SC to get more power out of a great car that LS is and I could pick 06 LS.



What more information do you need on the turbocharged LS? I hope you do not think I will give out full parts lists for the heck of it? I am sorry but if people really want a turbo for their LS then they can either talk with me, talk to another shop, or take the time to design and build their own. This is a car site and I provide tons of free performance advice and guidance here on the open forum and especially through PM, but the exact parts breakdown details on the turbo system are not going to be released except to customers.

Now, if you are talking about power results? Those will come in time but I feel my initial power estimates to be pretty accurate. The turbo has not even been done for a month, is 95% tuned and frankly I have not had much time to put the final touches on it and turn the wick up to 6 psi boost.

Jason you are basing that statement upon a friggin 10 second eyeball measurement in my garage, with no side by side teardown performed on the diff's. If there were more preliminary "real" measurements taken then I could see you stating what you said. Until I tear both diff's down and take detailed measurements with my machinist calipers it is all just bench racing for the moment. Don't put the cart before the horse on this one no matter how promising it initially appears.

I do not exactly trust what that fella said regarding things that were accomplished with that rear diff of his. I would take what the guy said for a grain of salt until there is really any solid results from this either on his end or another.

My comment didn't just come from the 10 second eyeballing. That came only after realizing it may be possible based on a few things I learned along the way on the project. Not just from what the other memeber showed. DTS also said the guts bolt in but the pinion was what needed to be worked out. DTS also suggested the Traction Lock while retaining the LS ring and pinion could work but since I wanted to gear up never concluded. Still alot left to figure.


Again its a "possibility" and "never been done".

so in conclusion if someone was really serious about a LSD but satisfied with the gear ratio, this would be the way "I" would pursue it. Maybe it would work maybe not.

What more information do you need on the turbocharged LS? I hope you do not think I will give out full parts lists for the heck of it? I am sorry but if people really want a turbo for their LS then they can either talk with me, talk to another shop, or take the time to design and build their own. This is a car site and I provide tons of free performance advice and guidance here on the open forum and especially through PM, but the exact parts breakdown details on the turbo system are not going to be released except to customers.

Now, if you are talking about power results? Those will come in time but I feel my initial power estimates to be pretty accurate. The turbo has not even been done for a month, is 95% tuned and frankly I have not had much time to put the final touches on it and turn the wick up to 6 psi boost.

Fair enough. Let's keep THIS on topic.

My comment didn't just come from the 10 second eyeballing. That came only after realizing it may be possible based on a few things I learned along the way on the project. Not just from what the other memeber showed. DTS also said the guts bolt in but the pinion was what needed to be worked out. DTS also suggested the Traction Lock while retaining the LS ring and pinion could work but since I wanted to gear up never concluded. Still alot left to figure.


Again its a "possibility" and "never been done".

so in conclusion if someone was really serious about a LSD but satisfied with the gear ratio, this would be the way "I" would pursue it. Maybe it would work maybe not.


Jason you have a PM. I will BS with you about this there since I do not want to take your thread off topic.

BTW 80MPH is 3000RPM. For those who were curious about the cruizing speeds. 65MPH is 2450RPM, I mentioned this before in the other thread I believe.

BTW 80MPH is 3000RPM. For those who were curious about the cruizing speeds. 65MPH is 2450RPM, I mentioned this before in the other thread I believe.

That's like in my 90 325i, no wonder that thing is ripping between the gears...

Okay I have a few questions.

What did you have done to the shaft, exactly.
Or would it just be easier to ask the shop to make another one like your's
How much did they charge to mod the shaft?


Did you do anything with the rubber quibo(sp) at the front end???

Okay I have a few questions.

What did you have done to the shaft, exactly.
Or would it just be easier to ask the shop to make another one like your's
How much did they charge to mod the shaft?


Did you do anything with the rubber quibo(sp) at the front end???

What you see in the pic is what was done. The rest of the shaft is stock so yes the rubber damper is still on the trans end. Cost me $60 to have it packed and shipped to them and the modification shipped back to me was $289.75 so $350.

To make a custom 2 piece would cost alot and not sure if worth it, If I was gonna shell out some coin I'd want the center bearing gone. A one piece would require a adapter at the trans end, likely a slide shaft there like the one pictured above to clear the shifter linkage(never measured to be sure) then a big shaft back. The gas tank limits diameter. There is maybe 3/4" between the stock rear shaft which is 2 1/4" diameter and the gas tank. Never measured exactly but I can just get my hand between there. That would mean a 3 1/2" would MAYBE fit but tight. Your not going to get by with a smaller diameter and 4" may be needed with the taller gears. The one piece shaft would be in the neighborhood of 61". A person could POSSIBLY shim the IRS(not the diff the entire IRS) in the car for more clearance. I stuck with this way for now but do toy with the idea of a one piece. It would be nice to loose the other rubber coupler and ditch the center bearing. It bounces alot on high RPM hard shifts in SST, at least it feels like it, I backed my shift pressure down cause of it awhile back while still on stock gearing.

Figured I'd add this pic and videos here as the original threads have faded off.


http://media.putfile.com/02-LSE-0-60

http://media.putfile.com/02-LSE-0-60-wspinning

If a person was capable of setting up there own ring and pinion they would only be out $200-$225 for the FRPP Traction Lock, could resell if didn't work. Actually a used one can be had for alot less tested and rebuilt if found to work.

Also Quik seems to have this set up started already. I PMed him on if he had a entire 8.8 guts in the stock LS diff or was it a 8.8 unit with the stock 8.0 ring and pinion fitted into the stock LS diff. He didn't know or want to tell me. Anyways if the bearing and main caps fit thats a good start but yes it hasn't been all figured out yet.

What do I care...I'm set already:D. If it is a matter of setting up the TractionLock carrier in the LS case, it should be a very easy swap for any moderately skilled DIY'er. The pinion depth won't change as we aren't messing with the pinion. Only the carrier bearing preload and backlash will need to be set. Here is the part of a good article relating to that very thing. http://www.corral.net/index.php?option=com_content&task=view&id=95&Itemid=26&limit=1&limitstart=3
Mustang TL's axles are 28 spline. 28 spline TL carriers should be almost free, as 28 spline axles don't hold up to stickshift launches on slicks for very long. Mustang guys upgrade to 31 spline often. The only special tools need would be a magnetic based dial indicator, a bearing press, and of course, hand tools, and a torque wrench.

I'm sorry to jack, but I have a quick question...

Where can I find an 8.8 with 4.10's and Trac-Loc? What cars in a junkyard would have them or just in general where?
They are a coveted item among Jeep Wrangler owners over the terrible Dana35 rear axle.

You'll have to get your own IRS 8.8 pumpkin and build it with a trac-loc and gears. I don't know of any cars that were IRS that came with 4.10s. Solid axle rears, I believe the Mountaineer/Explorers of a few years ago came with them.

If it is a matter of setting up the TractionLock carrier in the LS case, it should be a very easy swap for any moderately skilled DIY'er. The pinion depth won't change as we aren't messing with the pinion. Only the carrier bearing preload and backlash will need to be set. Here is the part of a good article relating to that very thing. http://www.corral.net/index.php?option=com_content&task=view&id=95&Itemid=26&limit=1&limitstart=3
Mustang TL's axles are 28 spline. 28 spline TL carriers should be almost free, as 28 spline axles don't hold up to stickshift launches on slicks for very long. Mustang guys upgrade to 31 spline often. The only special tools need would be a magnetic based dial indicator, a bearing press, and of course, hand tools, and a torque wrench.


You are operating off one assumption that could throw a wrench in your whole "easy swap for any moderately skilled DIY'er" plan . Are the carriers similar enough between the 8.0" and the 8.8" to allow an 8.8" LSD carrier to swap into the LS case with the original LS ring and pinion? Swapping to the entire ring and pinion plus the 8.8" carrier is very unlikely to work. The reason is that there will be a .4" difference in center to edge spacing between the 8.0" ring and the 8.8" ring. That difference will cause the gears to not mesh correctly between the 8.8" ring and pinion if attempted to be stuffed into an LS 8.0" case; which would try to force them .4" closer together than normal.

There are two additional possibilities that have been discussed in detail on the matter of getting an LSD into the LS without having to do the full swap like Jason and I did. One is the 8.8" LSD carrier swap to stock LS case, ring & pinion. I am not aware of anyone else having taken detailed measurements of the two carriers side by side. I have both in my garage now but I just have not taken the time to get out there, tear them both down and take some good measurements with my machinists calipers. The other is a Powertrax into the 8.0" carrier. Once again, assuming that the 8.0" carrier tolerances are the same internally as the 8.8" to allow the PTX to swap in without machining.



You'll have to get your own IRS 8.8 pumpkin and build it with a trac-loc and gears. I don't know of any cars that were IRS that came with 4.10s. Solid axle rears, I believe the Mountaineer/Explorers of a few years ago came with them.



If he is really lucky he might run across someone's junked Cobra that had 4.10's already stuffed into it. That would be pretty lucky though. I know the 96-01 Explorers came with the solid axle 8.8" but it had 31 spline axles. The 02+ have 8.8" IRS with 31 spline.

Would there be any really noticeable differences with an LSD and stock gears? Someone said something earlier to the effect that they were hardly needed.

An LSD with a stock set-up would surely help in the winter months around here. Never had a problem driving my 87 or 92 LSC in the snow or busting out of spots where I was plowed in. Not happening with the LS. Believe me, I've tried. :(

Would there be any really noticeable differences with an LSD and stock gears? Someone said something earlier to the effect that they were hardly needed.

In a highly modified LS with nitrous, turbo, or supercharger yes I would consider an LSD very necessary. On a regular bolton LS like most on the site I would not consider it necessary with stock ratio gears. Even when I ran 14.2's while N/A in my LS I didn't have any real traction issues to be concerned with.

However, LSD and gears like what Jason and I did on his LS would be a great swap for you guys that are looking for the next level of performance in your cars above the normal bolton mods. There is something else I might have in the works for you N/A guys also. I am trying to convince Jason to do it with his car, but we will see. Money doesn't fall from tree's though.

Some F-150s had 4.10's in their 8.8. And if my memory serves me correctly, the 00 Cobra R had 31 spline 8.8 traclock w/ 4.10 in an aluminum carrier. Don't quote me on that though... could have been 3.73... and besides; you're not going to find one of those anyway!

Anyone try the powertrax? An LSD would be really nice for those days where I take the car out in the snow up here (although it's usually the truck that sees snow service)!

Jason and Rob,

Its been a while since ive came onto these boards now that im a VW driver (please no neg comments for me :( ) But last time i heard about this project is when I dropped off my stock LS diff at Robs house. Did you guys ever find a good use for it??

Jason, I saw your vid of the 0-60, OH MY GOD, that is amazing man!! congrats. If you guys go up to GLD this spring, I want in please let me know, ill bring tim (kid with 03 LS8 who Rob tuned..) Mad props to both of you, im on my florida vacation right now and just spent a good hour reading the turbo and LSD threads..

-Devin

Jason and Rob,

Its been a while since ive came onto these boards now that im a VW driver (please no neg comments for me :( ) But last time i heard about this project is when I dropped off my stock LS diff at Robs house. Did you guys ever find a good use for it??

Jason, I saw your vid of the 0-60, OH MY GOD, that is amazing man!! congrats. If you guys go up to GLD this spring, I want in please let me know, ill bring tim (kid with 03 LS8 who Rob tuned..) Mad props to both of you, im on my florida vacation right now and just spent a good hour reading the turbo and LSD threads..

-Devin


Devin it is good to hear from you bud. Your stock diff was used for mockup in the planning stages of the project.

What VW do you have? I plan to do a custom turbo on the bro's VR6 Jetta this coming summer actually.

Jason and Rob,

Its been a while since ive came onto these boards now that im a VW driver (please no neg comments for me :( ) But last time i heard about this project is when I dropped off my stock LS diff at Robs house. Did you guys ever find a good use for it??

Jason, I saw your vid of the 0-60, OH MY GOD, that is amazing man!! congrats. If you guys go up to GLD this spring, I want in please let me know, ill bring tim (kid with 03 LS8 who Rob tuned..) Mad props to both of you, im on my florida vacation right now and just spent a good hour reading the turbo and LSD threads..

-Devin
Thanks. She runs pretty strong.

Your cover is in my car on the 8.8, I left mine assembled. Rob still has the rest of your diff for experimenting.

You'll have to get your own IRS 8.8 pumpkin and build it with a trac-loc and gears. I don't know of any cars that were IRS that came with 4.10s. Solid axle rears, I believe the Mountaineer/Explorers of a few years ago came with them.

03-04 Mustang Cobras-IRS, aluminum pumpkin, 3:55's or 3:73, 31 spline axles. (99-02 IRS Cobras had 28 spline axles). You can get these real cheap because any Cobra owner making over the advertised 390 hp, swaps them out for a straight axle.

03-04 Mustang Cobras-IRS, aluminum pumpkin, 3:55's or 3:73, 31 spline axles. (99-02 IRS Cobras had 28 spline axles). You can get these real cheap because any Cobra owner making over the advertised 390 hp, swaps them out for a straight axle.



No they do not. There are plenty of Cobra owners pushing well past 600+ hp on the 8.8 IRS. Usually when they get past about 550rwhp is when they swap to the DSS Level 5 halfshafts and hubs though. Actually a very small percentage of Cobra owners swap from their IRS to solid even when modified.

If a person is trying to locate an 8.8 pumpkin it is best to just go for a Mark 8 one. They are much easier to locate and much cheaper as well.

No they do not. There are plenty of Cobra owners pushing well past 600+ hp on the 8.8 IRS. Usually when they get past about 550rwhp is when they swap to the DSS Level 5 halfshafts and hubs though. Actually a very small percentage of Cobra owners swap from their IRS to solid even when modified.

If a person is trying to locate an 8.8 pumpkin it is best to just go for a Mark 8 one. They are much easier to locate and much cheaper as well.

Let me narrow my comment to drag racing only. Road racers or street racers would be the only ones foolish enough to put that kind of money in an IRS that weighs 125lbs. more than the 8.8 straight axle.

Let me narrow my comment to drag racing only. Road racers or street racers would be the only ones foolish enough to put that kind of money in an IRS that weighs 125lbs. more than the 8.8 straight axle.


I know quite a few people who dragrace their Cobra's and do not swap to solid rears even when running full slicks at a well prepped track. I have friends who have Cobra's I have done work on and most have not swapped from their IRS to solid. On one particular local SVT site I am a part of there are mostly terminator owners on there. Most are running anywhere from 425-600rwhp through the IRS varying from bone stock IRS to the DSS equipment being added. Very very few swap to solid rear until they go with a Big 2.8H KB, Whipple 3.3 or a turbo system. That goes for many many other people not on that site as well. There are very few Cobra owners that swap to solid rears. And of the few that do, they usually swap with a Mustang GT owner for their solid rear. The GT owner gets an IRS and the Cobra owner get the solid rear setup. That means no leftover parts. You show me one Terminator owner running 600rwhp or less and a solid rear and I will show you 75 more that are running their IRS at the strip.

Okay so I'll ask the loaded question then.
If I can find a cobra irs for less than a mark's irs, is there any reason I should not go for it?

I'm looking to do a lsd swap into my current ls (the 'family' car) and another when I get moving on the v8 manual swap.

Okay so I'll ask the loaded question then.
If I can find a cobra irs for less than a mark's irs, is there any reason I should not go for it?

I'm looking to do a lsd swap into my current ls (the 'family' car) and another when I get moving on the v8 manual swap.

From what I understand early IRS Cobras are 28 spline and are the same as the MarkVIII diff. Cobras did switch to 31 spline in I believe 03, that you wouldn't want.

If you search the MarkVIII forum you should find some info on them being interchangable.

Okay so I'll ask the loaded question then.
If I can find a cobra irs for less than a mark's irs, is there any reason I should not go for it?

I'm looking to do a lsd swap into my current ls (the 'family' car) and another when I get moving on the v8 manual swap.



The possibility of that happening would be a very rare thing, but like Jason said if you can find one from the 99-01's then it should serve as a decent starting point to build off of.

My differential is making noise so I want to upgrade.

What would I need to get any kind of LSD into my LS?

so.... what exactly do i need to swap in some shorter gears for better acceleration? just the new gears? or a whole new rear end?

My differential is making noise so I want to upgrade.

What would I need to get any kind of LSD into my LS?

Fitting a LSD devise into the stock LS unit hasn't been done but the guts do have similarities to 8.8 units.

Doing what I did is the only way its been done that I know of.

so.... what exactly do i need to swap in some shorter gears for better acceleration? just the new gears? or a whole new rear end?

3.58 is the tallest gear that came stock in the LS, depending on your year, you may already have it. If you don't it would be cheaper to just get a unit with the 3.58s already in it rather than a build.

If you want more you have to swap in the 8.8 unit as I did.

Jason when do you plan to go to the track this year?

Jason when do you plan to go to the track this year?

Soon as can.

Soon as can.


I will probably be there with you. I want to see how the cars run this year. I am curious to see how your car reacted to the 4.10's.

I will probably be there with you. I want to see how the cars run this year. I am curious to see how your car reacted to the 4.10's.

Hard to say exactly. She really has some quick pull, very different car at the low speeds. I can't imagine not gaining .3-.4 and 2-3mph. Should be high 13 territory, but till its done thats just talk.

I'm very curious to see what you can do. Going to do the LSD first right?


Haven't drivin it in at least a month and probably a month before that.

Hard to say exactly. She really has some quick pull, very different car at the low speeds. I can't imagine not gaining .3-.4 and 2-3mph. Should be high 13 territory, but till its done thats just talk.

I'm very curious to see what you can do. Going to do the LSD first right?


Haven't drivin it in at least a month and probably a month before that.



I would not be surprised at all if you hit 13's as we had talked about in our previous conversations. We will have to see what it can do.

I do intend to do the LSD first now that I have measured it and things will slide right into the stock carrier. If I had to do the full 8.8" swap with axles and custom brace then I would have probably waited till mid summer before doing that.

The last time I drove the LS was early January when I took care of that slight lean tip in in the somewhat nicer weather we had. Had fun with it for a few hours while logging it and then put it back away for the duration of winter.

I would not be surprised at all if you hit 13's as we had talked about in our previous conversations. We will have to see what it can do.

I guess what will be interesting is if 13.9 will be my "best" run or runs or will I belt that out everytime and see room to sneak a little better time. We will see.


Its hard for me to predict how much better a 60' I will get. A full .1 improvement??

Talking about it gave me a itch. So I brushed her off and took a spin.


Chirped 4th getting on a freeway. Thats right 4th!

Talking about it gave me a itch. So I brushed her off and took a spin.


Chirped 4th getting on a freeway. Thats right 4th!



Hehehe. That is funny. I too am getting the itch. I have to resist it though due to the nasty salt still being on the roads for a while longer.

While the roads are a little dusty here, they are really dry. We missed the last few storms.

Chirped 4th getting on a freeway. Thats right 4th!

Blow Me! More like slipped on the sand/salt changing lanes.

Chirped 4th! Good grief. That tranny must be on its last legs.

I, on the other hand, also took the beast out for a day in the sun today. Just to hear the motor turn over and the thunder bellow from the exhausts made my willie do a wheelie. Unfortunately the racing Goodyears picked up every grain of sand on the road and tossed it with sand-blasting efficiency all over the undercarriage and rockers, thus preventing the climax.:) I could have spun every gear had I wanted.

Blow Me! More like slipped on the sand/salt changing lanes.

Chirped 4th! Good grief. That tranny must be on its last legs.

I, on the other hand, also took the beast out for a day in the sun today. Just to hear the motor turn over and the thunder bellow from the exhausts made my willie do a tand up wheelie. Unfortunately the racing Goodyears picked up every grain of sand on the road and tossed it with sand-blasting efficiency all over the undercarriage and rockers, thus preventing the climax.:)

Some of the main streets are surprizingly clean if you stay in the tracks. She chirped, swear. If your not fimiliar when we use the SST mode in our car it shifts way harder than auto even without a tune. With the pressure jacked up it really slams the gears solid in SST.

I have my shift pressure down all 25% too.

I found that when going down the track sometimes I felt more driveline bounce than forward thrust. That and discovering that we have a flex coupler(Guibo) driven 2 piece shaft with center bearing, led me to roll her down. She still is too hard and unfortunately to soft in auto mode. I'm going to get a new tune with the auto slightly higher and the SST mode lowered some. Should be good.


Edit: Remember 4th is our 1to1 gear, its not my overdrive....its not a dinosour you know.

Blow Me! More like slipped on the sand/salt changing lanes.


She chirped, swear. If your not fimiliar when we use the SST mode in our car it shifts way harder than auto even without a tune. With the pressure jacked up it really slams the gears solid in SST.

Edit: Remember 4th is our 1to1 gear, its not my overdrive....its not a dinosour you know.




I smell a race coming on... Family competition hey? ;)




You guys race and I will hold the money................and getaway in my LS.