Road course differential advice

[customstreetmachines]

I need a little advice. I am building a pro-touring 67 camaro for road coarse flogging. LS2/T56 w/ ford 9". I have run GM posi's on road coarses before, but never as heavily as I intend to shred this car. I have a Detroit locker in My Chevelle and it works great at the dragstrip, but seems like it might kick that back end around on corners because of the mechanical type locking, But my Chevelle is set up to go straight, so it may be a bad example for me. I need a good differential that can handle 500+ ft lbs and I plan on flogging the pee out of it. What are your thoughts Locker, Auburn cones, Air locker ????

[Scott Parkhurst]

I like the Eaton/Detroit Tru-Trac. No clutches to wear, and it offers partial engagement around corners (rather than the 'on/off' action of a Locker). It's all helical gears, so it's a solid piece with no parts that'll wear out (like a clutch will).

I haven't beat the snot out of mine (yet) but the research I did led me to it.

~SP~

[parsonsj]

I'm a big fan of Lockers. Mine works great on the street, the autoX, and on big tracks.

jp

[andrewb70]

I like the Eaton/Detroit Tru-Trac. No clutches to wear, and it offers partial engagement around corners (rather than the 'on/off' action of a Locker). It's all helical gears, so it's a solid piece with no parts that'll wear out (like a clutch will).

I haven't beat the snot out of mine (yet) but the research I did led me to it.

~SP~

Scott,

Is that the same diff that is used by Ford in the 03-04 Cobra Mustangs?

Andrew

[chicane67]

Lockers take a little finesse' to drive. Auburn sucks. ARB wont live in an impact loading enviornment...

If it were me... I bust out a Platinum Track (http://www.dpiracingproducts.com/platnumtrkdiff_htnws.htm) (definate, first choice) or a Black Gold (http://www.dpiracingproducts.com/blkgolddifnacs.htm) from DPI.

Or a true Torsen Gleason.... but no one wants to spend $1200.00 on a differential.

But what do I know ??

[Damn True]

Do you have any kind of metrics on the surviability of the above on the street? I mean are they a maint. intensive unit?

[chicane67]

No more maintence than that of an EATON True-Trac. And in my opinion... much less. The machining tolerances and finished components are much cleaner than an out of the box True Trac.

I know of several Black Golds that have been street driven behind 700-800hp big block cars for 20 years... and a decade or two of abuse in professional motorsports (Nascar, SCCA... etc) that would seem more like a few hundred thousand miles of street use.

The only real difference between the two is that the Platinum Track is bias pre-load tunable. Meaning... that you can add or take out bias pre-loading when the center section is out of the housing. It would be likened to a breakaway adjustment in tuning a limited slip clutch unit.

Im all over the Platinum Track. Next to a true TG... its the cats @ss for road course, AX and land speed stuff.

[Damn True]

Yeah, you had me all ate-up for that TG....until I saw how much they cost. Are the Platinums and/or Black Golds a bit more wallet friendly?

[chicane67]

The BG units are $675 for a no pre load unit... and $775 for a 1/2, 3/4 or full tight pre load unit. The "Street Rod" unit is $875.

The PT units are $750ish

[funcars]

I have a black gold that I use on the street and on the track. It works great and makes a difference on a road race track. I have a full tight version. DPI is a good outfit and can rebuild it if it ever needs it and they even provide instructions for doing it yourself. I sent them the third member a while back and they put in new ring and pinion in it in two days since I had a BG in it already.

[molyorange 77]

TrueTrac's are pretty darn durable. I had one installed over a year ago and I have Pounded on it.

[customstreetmachines]

I have heard good things about the True Trac's. The DPI diff's seem a little pricey, although they are probably well worth the money. I haven't even bought a housing yet, I am still researching. I am looking to keep it under $2k for a complete 9", not including brakes. I'd like to see some others chime in on the True trac and other diffs you guys are running.

[matthimself456]

My vote goes to the TruTrac style torsen differential. Research how they work a little. Its like pure mechanical magic.

[chicane67]

True Trac's are a good unit... but, in my opinion... they need to be diassembled, case de-burred and the pinion gears to be heat treated, cryo-ed, REM'ed (or Micronite) and then reset the mechanical lash a little tighter (they need a little pre-load).

The True Trac will take lots of abuse... as long as you dont go to the local drag strip and impact load it to death. If you go to a couple other sites... you too will see the numerous posts of people blowing True Tracs up. The biggest culprit in 99% of the related failures are from inexperienced differential builders installing the wrong differential into the wrong application... and inexperience drivers listening to the susposed 'experts' and taking what they hear as the gospel. Well... stupid is as stupid does.

As I stated before... a True Trac is a great differential... as long as you dont impact load it to death. Or if you do go to the strip... just pray that you dont hook up too hard, one too many times.

FYI... the Torsen Gleason, the Black Gold/Platinum Track and True Trac work mechanically the same. The Torsen Gleason and the Black Gold/Platinum Track are by far the strongest (or NASCAR, IMSA, SCCA wouldnt use them) and more expensive differentials. The Torsen Gleason runs about $1200 and the BG/PT run $675-750... and the True Trac (untuned) runs $375.

Let me put it another way... and simplify it... you get what you pay for in terms of strength. $675 once is cheaper than $375 twice or until you learn that you should have done it right the first time around.

Even Tom specifically states not to use it in a drag race application: http://www.tomsdifferentials.com/catalog.asp?pg=72

I also like the Detroit Locker. But... as I said earlier... it takes a little finess to drive and I wouldnt want to drive it on any thing other than dry pavement. Hell... as for that subject... I dont even like to run some of my tuned limited slips on anything other than dry pavement.

And since you stated this:


I have run GM posi's on road coarses before, but never as heavily as I intend to shred this car.

And this:


I need a good differential that can handle 500+ ft lbs and I plan on flogging the pee out of it.

You pretty much have ruled out about all other differentials... other than that of a Torsen Gleason or either of the Black Gold or Platinum Track units.

[customstreetmachines]

Well, I definately don't want to blow it out and do it twice. Spending the money to do it right is not out of the question, but I try to start with a budget (which almost never works). Tell me the characteristics that require "finesse" with the locker. My only experience with them is in cars set up to go straight. So, turning corners on the street I can feel it unlocking and locking. Otherwise it seems almost indestructable with dragstrip launches with 450 ft lbs, 3.26 1st gear a 3.90 rear gear. Is the black gold as strong as the detroit locker? Can it handle a couple of hard launches? I like the all around car aspect of pro-touring, but I am really leaning on the road coarse with this build.

[Steve1968LS2]

I'm going ot Currie next week to do a story on building a third member for the road track.

Suggestions? We will go over the differences in yokes, carriers, cone vs clutch, etc.

I was planning on building a nice 4.10 unit for Penny.. Detroit TruTrak and all the goodies.

What do you guys wanna see?

[chicane67]

You will only feel a locker 're-set' when you come out of a turn, as you progress back into a straight line. Then... BANG. It re-sets... and sometimes it can induce a lane change weather you intended to or not, from the re-set. Trail braking is going to be another learning curve for your road course duty.

Light moisture or really hot pavement will also easily induce oversteer. But if the dove tails are loaded (under accleration or deccleration) it can induce understeer if the chassis hooks up.

The DPI units are rated at 750hp... so I think it will do just fine at your power level and I think it will take impact loading much better than the True Trac in comparison. The finished components of the DPI units are far better pieces from a machining stand point.

[chicane67]

I'm going to Currie next week to do a story on building a third member for the road track.

Suggestions? We will go over the differences in yokes, carriers, cone vs clutch, etc.

I was planning on building a nice 4.10 unit for Penny.. Detroit TruTrak and all the goodies.

What do you guys wanna see?

I told you where you should have gone for this stuff... but say HEY to Ray and Chuck for me anyway.

I would concentrait any story explaination on bearing pre-load and how to do it and get it right... and on gear pattern and what it takes to do it and get it right. Get plenty of pictures of the gear pattern stuff. Pinion support assembly will be part of the bearing pre-load stuff... but its assembly is pretty important stuff.

You need a 3.062" Mark Williams thru bolt case... a DPI Platinum Trac... a Williams tapered pinion support... and some EDM lightened Visteon 4.10's. Oh wait... they dont have that kinda stuff. oops...

Seriously though. you... need a CE-4028A alloy 3.062" case, a CE-4048C alloy big bearing pinion support, a CE-5021 DPI Platinum Track or an Eaton True Trac... and... I would pony up the $150 extra for a lightened gear set, if... if... they will do that ratio. Especially if they have some USGear 4.10's in stock. And... a CE-4044B billet 1350 yoke.

Or purchase all of the MW stuff and Ill teach you to do your own differentials for free. 'Give a man a fish and he has a meal. Teach a man to fish and he eats for life'.

[Steve1968LS2]

I told you where you should have gone for this stuff... but say HEY to Ray and Chuck for me anyway.


I go where I'm told to go ;)

But I will do my best...

[Steve1968LS2]

Seriously though. you... need a CE-4028A alloy 3.062" case, a CE-4048C alloy big bearing pinion support, a CE-5021 DPI Platinum Track or an Eaton True Trac... and... I would pony up the $150 extra for a lightened gear set, if... if... they will do that ratio. Especially if they have some USGear 4.10's in stock. And... a CE-4044B billet 1350 yoke.

Gotcha.. I can pretty much choose anything from the Currie catalog.. as long as my 31 spline axles work I'm golden.

Is that case iron or aluminum? I've heard the alum cases aren't great for longevity. I don't think Currie offers the DPE Platinum deal so it will be a Eaton Ture Trac. Gotcha on the rest.

[Steve1968LS2]

Never mind.. I found the case.. nice!

How about it compared to iron for durability? Not like Penny is a daily driver but still.. thoughts?

http://www.curriejeep.com/CEStore/Product.aspx?id=2096

Here's the pinion support you mentioned:
http://www.curriejeep.com/CEStore/product.aspx?id=1657

And here's the diff.. man, that's spendy...

How much better is it than the True Trac and is it as good on the street?

http://www.curriejeep.com/cestore/productsRE.aspx?id=1647

[chicane67]

Dont forget... not the polished one... the "as cast" unit. I just wish it had a 'load bolt' provision.

Durability ?? Not a question. The Strange case is more than adequate for the application. Plus your not trying to launch it on slicks at LACR for a living. I wouldnt even think twice. What you gain in weight savings helps the suspension ten fold. Not to mention... that if it were put together correctly the first time... there should'nt be an issue for its entire life. The only Iron case that I would consider would be the Mark Williams 57460 or my choice the 57465 case.

As for the cost... I did mention an alternate approach. Currie isnt really moola friendly on certain components... and that is one of them. And... if you actually read this thread... my previous comments sum it up. $675 once... is cheaper than $375 twice. Oh yeah. They want $875... :eek:

Its the difference between night and day. Not to mention the strength is far and above that of an 'out of the box' True Trac. Unless you want to take it apart as I explained earlier in this thread and spend another $300 to tune it correctly. ? Naw... I didnt think so either.

You better squeeze Ray for the good guy price.

[parsonsj]

I'm using the Moser as-cast aluminum case. So far, so good.

jp

[Steve1968LS2]

Dont forget... not the polished one... the "as cast" unit. I just wish it had a 'load bolt' provision.

Durability ?? Not a question. The Strange case is more than adequate for the application. Plus your not trying to launch it on slicks at LACR for a living. I wouldnt even think twice. What you gain in weight savings helps the suspension ten fold. Not to mention... that if it were put together correctly the first time... there should'nt be an issue for its entire life. The only Iron case that I would consider would be the Mark Williams 57460 or my choice the 57465 case.

As for the cost... I did mention an alternate approach. Currie isnt really moola friendly on certain components... and that is one of them. And... if you actually read this thread... my previous comments sum it up. $675 once... is cheaper than $375 twice. Oh yeah. They want $875... :eek:

Its the difference between night and day. Not to mention the strength is far and above that of an 'out of the box' True Trac. Unless you want to take it apart as I explained earlier in this thread and spend another $300 to tune it correctly. ? Naw... I didnt think so either.

You better squeeze Ray for the good guy price.

Polished?? PLEEEEESEE... lol.. the less I have to clean under there the better :)

Squeeze for a good price??? lol.. you're so cute :)

[CarlC]

.....any story explaination on bearing pre-load and how to do it and get it right... and on gear pattern and what it takes to do it and get it right. Get plenty of pictures of the gear pattern stuff. Pinion support assembly will be part of the bearing pre-load stuff... but its assembly is pretty important stuff.


Ditto. The greatest components in the world won't work if they are improperly assembled.

[Steve1968LS2]

Ok, here's what we're building:

CE-4028A alloy 3.062" case
CE-4048C alloy big bearing pinion support
Eaton True Trac
Midwest 4.10 gears
CE-4044B billet yoke OR their iron yoke.

As for the yoke they feel it's nearly as strong as the billet unit, and at my power level is more than capable.

I would lighten the gear set but it will take 2-3 weeks to get it done. I don't have that much time due to deadlines. I will discuss it though. The Midwest gears are equal to the USGear.

The Platinum track was way to expensive, I'm not building a racecar.

I want to discuss the benefits of weight and all the different options specific to a "road race" third member compared to a "drag race" unit.

Shooting the build/story next week.

[chicane67]

Next week huh ??

Well... you will need to look at the Jerico web site, specifically their catalog, for some eye opening stuff on the subject of lightening components.

You will also want to look at the Mark Williams site and catalog... as they too have a bunch of low friction options as well as being the best products currently made in the market. Oh yeah... they also have some great lightening tricks up the sleeve too.

And... you may as well throw the hat in the ring and possibly talk about REM finishing and cryo treatments. These topics at least cover all differential builds and are not subject to one specific application.

And by the way Steeve... PlatinumTracks are not just for race cars. I myself... just hate to spend money twice.

Oh. Yeah. Midwest gears are not quite the same... but then again I am not trying to sell you something either.

[Payton King]

Steve what gear were you running? I am thinking of going up on my set as well. I am turning 1500 at 65 mph and would like to raise it a bit.

I have a 9 inch with a set of 3.80 gears and a tru-trac. The gear set came from Hendrick race team here in Charlotte. They have been polished.

My question is the rear howls on the pull side but is whisper quite on the coast or decel. Is this a diff problem or a lash problem?

6th gear, 2000 rpm, 80 mph it almost sets up a harmonic in the car.

[chicane67]

Gear patterns for race cars are a little different than it would be for patterns for street cars.

Race car:
https://static1.pt-content.com/images/pt/2008/03/contactb-1.gif

The drive side of the tooth is set up a little toe to combat tooth loading and deflection. Since race cars and noise are an all in one package... the noise from the gear set up is acceptable.



Street car:
https://static1.pt-content.com/images/pt/2008/03/contacta-1.gif

Since passenger cars (the idea of them) are more for comfort vice 800hp high bank pavement pounders... the noise is somewhat unacceptable to the masses. Not to mention, that they were not designed and/or produced with the idea of and level of performance that mere mortals ever needed.

[James OLC]

For what it's worth we are running a DPI platinum track in the OLC Camaro. When we were laying out the the rear end design with Mark Williams I asked their chief tech what differential he would recommend in a road racing, ORR, autocross environment and his answer, with no response was the DPI unit. What really impressed me was that he then went on to say that they do not stock nor sell the DPI unit but suggested that I contact them directly and make arrangements to get one straight from DPI. Besides the obvious pleasure dealing with someone who is truly out to ensure that a customer or potential customer gets what is best suited for him regardless of his line card, the guys at MW went out of their way to explain the benefits, pro's and con's.

At the end of the day though, the pretty much told me the exact same things that Tom had told me when we first started talking about differential options....

[Payton King]

so what you are telling me is I am going to have to live with the whine for the durability trade off...not a problem

This is the first 9 inch that I have owned and the guy who set it up does circle track cars, so I am sure it is correct.

Thanks for you time to post.

Payton

[Steve1968LS2]

Next week huh ??

Well... you will need to look at the Jerico web site, specifically their catalog, for some eye opening stuff on the subject of lightening components.

You will also want to look at the Mark Williams site and catalog... as they too have a bunch of low friction options as well as being the best products currently made in the market. Oh yeah... they also have some great lightening tricks up the sleeve too.

And... you may as well throw the hat in the ring and possibly talk about REM finishing and cryo treatments. These topics at least cover all differential builds and are not subject to one specific application.

And by the way Steeve... PlatinumTracks are not just for race cars. I myself... just hate to spend money twice.

Oh. Yeah. Midwest gears are not quite the same... but then again I am not trying to sell you something either.

I know PlatinumTracks arn't JUST for race cars :)

The story is at Currie, so I need to do it on parts they have. I will discuss the DPI and Detroit units, I'm just using the Detroit unit.

So, what's wrong with the midwest gears compared to the USGear? They use to use the USGear but USGear couldn't keep them supplied.

The lead time killed me on getting a set of gears lightened. They are digging around the shop to see if they have a set already done. At the very least I will discuss the topic.

I'm pretty much going to go over a "cost is no object" diff and then a more wallet-friendly option. My unit is a compromise based on money and, in some regards, to the time frame I have to work in. Hopefully I can make the story educational.

At the end of the day Penny is still a street car that will occasionally see some track time and not the other way around.

[chicane67]

Here is where you got into trouble:


I'm going ot Currie next week to do a story on building a third member for the road track. Suggestions?

And then you stated this:


The Platinum track was way to expensive, I'm not building a race car.

So which is it going to be Steve-O ??

I will try and surmise all of this... with a simple statement:

At this level, street cars are merely race cars with license plates. :enguard:



We can talk about the gear difference in a private setting sometime...


Next... on your full blown build speal... don't forget to add the EDM lightened gear sets from Tex Racing, a MW titanium yoke and throw in a pinion driven gear pump for the cooling efforts. :twothumbs

[Steve1968LS2]

Here is where you got into trouble:



And then you stated this:



So which is it going to be Steve-O ??

I will try and surmise all of this... with a simple statement:

At this level, street cars are merely race cars with license plates. :enguard:



We can talk about the gear difference in a private setting sometime...


Next... on your full blown build speal... don't forget to add the EDM lightened gear sets from Tex Racing, a MW titanium yoke and throw in a pinion driven gear pump for the cooling efforts. :twothumbs

Ok, you're right.. I give..

I should have said..

"I'm going to Currie next week to do a story on how to choose parts for more "road race" g-Machine car. And even though some of the parts won't be the "full race" versions I will still address those parts in the story. After all, Penny is far more of a street car."

How was that? lol

Titanium Yoke? Well, this isn't circle track magazine.. I don't know how far I will get into the total race stuff. I'm sure we will talk when I get down to writing the story. :)

[chicane67]

Yup, Titanium. But, its not for left handers...

[Steve1968LS2]

Yup, Titanium. But, its not for left handers...

What I meant is that some of the more exotic, and expesive, stuff is more towards the race side where people are spending tons to be a hair faster. In other words it's more on the "race car" side of the equation.

How much does a Titanium yoke cost? Just curious...

[Damn True]

Can someone PLEASE edit the title of this thread?

It's driving me up the wall.

[fast Ed]

Scott,

Is that the same diff that is used by Ford in the 03-04 Cobra Mustangs?

Andrew

Andrew, the 03-04 Cobras used a standard Ford traction-lock differential, but with carbon fibre clutch packs.


cheers
Ed N.

[parsonsj]

Can someone PLEASE edit the title of this thread?

It's driving me up the wall.Glad I'm not the only one!
jp

[chicane67]

What I meant is that some of the more exotic, and expesive, stuff is more towards the race side where people are spending tons to be a hair faster. In other words it's more on the "race car" side of the equation.

How much does a Titanium yoke cost? Just curious...

There are things that I do and its not just to go a hair faster... it is also for saftey, reliability and weight managment. Especially for anything related to rotational inertia.

They are 'bout seven bones.

[Steve1968LS2]

'bout seven bones.

Point made :)

[Steve1968LS2]

Glad I'm not the only one!
jp

Maybe it's just a very rough road??? ;)

[Neil B]

I ran an Auburn in my Camaro-Mustang Challenge road racer and it lasted 6 races. I replaced it with a Detroit C-Locker and it was still going strong after 4 seasons. The lockers will corner a little more tail-out (yaw) when you're on the throttle; at first, it's a little unnerving mid-way through fast corners, but you quickly get used to it.

[rohrt]

Can you expand on the lightend gears? Great thread by the way.

thanks

[Damn True]

Maybe it's just a very rough road??? ;)

Oh Sebring?

[fast Ed]

I ran an Auburn in my Camaro-Mustang Challenge road racer and it lasted 6 races. I replaced it with a Detroit C-Locker and it was still going strong after 4 seasons.

The Auburn in my 5.0L Mustang (with a mild engine mind you) went for about 12 races, and probably that many Solo I weekends as well, before it cacked. Worked quite nicely up to that point. The car was street driven in that time as well.


cheers
Ed N.

[chicane67]

Point made

What was the point again ?? I dont remember. I thought we were throwing out ideas for the ultimate build diggs for the possible article. :spank2:





Can you expand on the lightend gears? Great thread by the way.

thanks

What exactly would you like to know specifically ??

[Steve1968LS2]

What was the point again ?? I dont remember. I thought we were throwing out ideas for the ultimate build diggs for the possible article. :spank2:


Just that it's more of a race part. Rather than "ultimate" I guess I should have said the "right" parts for a g-machine. "right" being a part that will perform well at a realistic price and a g-machine being a street car that likes to visit auto-x and road deals.

Mostly I'm just messin with ya ;)

A $700 yoke? Damn..

[Steve1968LS2]

The Auburn in my 5.0L Mustang (with a mild engine mind you) went for about 12 races, and probably that many Solo I weekends as well, before it cacked. Worked quite nicely up to that point. The car was street driven in that time as well.


cheers
Ed N.

I killed two Auburns in my 2000 SS. Once at the drag strip and once at Buttonwillow.

[chicane67]

Mostly I'm just messin with ya ;)

Who... you ??


Nooooooooo...:ssst:

[derekf]

Can someone PLEASE edit the title of this thread?

It's driving me up the wall.

Done, at least assuming that's what was bugging you.

[parsonsj]

Done, at least assuming that's what was bugging you.Thanks Derek!

jp

[Damn True]

Muuuch better, thanks!