1998 Formula Firebird LS1/T56 - ESP build Options

[FlatBlack]

Hello all,

Just picked up a 1998 Formula that I will be prepping for ESP class in SCCA Autocross. It's Blurple, but I don't care too much about my cars look (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

I have some other things to take care of first, but wheels (17x9 or 10+) and suspension should come soon. I plan on Koni yellows and GC coilovers.

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140226_175210.jpg)

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140226_175226.jpg)

This post has been edited by FlatBlack: Feb 27 2014, 10:22 PM

[trackbird]

35mm front sway bar and a 21mm solid rear or 22mm hollow rear. The "standard" ESP setup on these cars is 550 or 600 in lb front springs, 150 in lb rear springs, a good quality panhard bar and an alignment with as much negative camber as you can get (typically about -1.1 degrees...give or take a bit), 5 to 5.5 degrees of castor and 0 toe to 1/32" of toe out.

Add 17x11" wheels on all 4 corners and install the sticky tires of your choice and a good clutch type differential and you should be off to a good start.

[Racer X]

Just picked up a 1998 Formula that I will be prepping for ESP class in SCCA Autocross.

Words you never imagined would come out of your beard hole.

I'm still f'n dying over here.....

(IMG:http://www.frrax.com/rrforum/style_emoticons/default/rotf.gif)

[camarokid91]

I like Blurple and Trans ams so I approve. I just wish you where in my region I need more competition in ESP. New England is just me in ESP hanging out with Sam Krauss in his DSM.

[CrashTestDummy]

I like the color, too. You may be at a slight disadvantage with the t-tops, but it should still be fun.

[FlatBlack]

I like the color, too. You may be at a slight disadvantage with the t-tops, but it should still be fun.

Did they make a slicktop Firebird?

Hadn't thought about it. Are they heavier?

[CrashTestDummy]

Hmm, I don't know if they did make a slicktop 4th Gen Fbird or not, or the weight. The extra weight for the reinforcement and all that glass is high and forward, not where you want it in an autocross situation. Additionally, and gain, I'm not sure about 4th Gens, but 2nd and 3rd Gens with t-tops were a bit more 'flexible' than the hardtop versions. I don't think you can overcome that issue in ESP.

But still, it has an LS engine, which has a TON of potential, and you can have a lot of fun in it. I think the Firebird actually has a bit more room in the wheel houses, so getting even more tire under the car, as opposed to a Camaro, may be possible. I'd get under the car and look around, though. 18" wheels may afford you more space to tuck more wheel and tire under the car. 18" wheels fit a lot better, especially under the front end, than a 17" wheel on a 3rd Gen. I know they have different front suspensions, especially up front, so you'll have to do some research yourself.

Since Watts Links are legal (bolt-on only, IIRC), you may want to look into that to put on your mods list. They really help the 3rd Gens.

[FlatBlack]

Hmm, I don't know if they did make a slicktop 4th Gen Fbird or not, or the weight. The extra weight for the reinforcement and all that glass is high and forward, not where you want it in an autocross situation. Additionally, and gain, I'm not sure about 4th Gens, but 2nd and 3rd Gens with t-tops were a bit more 'flexible' than the hardtop versions. I don't think you can overcome that issue in ESP.

But still, it has an LS engine, which has a TON of potential, and you can have a lot of fun in it. I think the Firebird actually has a bit more room in the wheel houses, so getting even more tire under the car, as opposed to a Camaro, may be possible. I'd get under the car and look around, though. 18" wheels may afford you more space to tuck more wheel and tire under the car. 18" wheels fit a lot better, especially under the front end, than a 17" wheel on a 3rd Gen. I know they have different front suspensions, especially up front, so you'll have to do some research yourself.

Since Watts Links are legal (bolt-on only, IIRC), you may want to look into that to put on your mods list. They really help the 3rd Gens.

Korry (Racer X) has a Watts link, and he likes it alot. I'd planned on it since they are reasonably priced, but I'm worried about all the clearance issues with the exhaust and swaybar. Probably won't do it for a while anyways, Korry has an adjustable panhard bar for me.

[Racer X]

I like Blurple and Trans ams so I approve. I just wish you where in my region I need more competition in ESP. New England is just me in ESP hanging out with Sam Krauss in his DSM.

The wife and I are working on moving back to the northeast. NE PA may be a bit too far from you though. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/wink.gif)

Hmm, I don't know if they did make a slicktop 4th Gen Fbird or not, or the weight.

They did but were almost impossible to find on a lot. I really only remember seeing one. An '01 Formula Firehawk of all things. Usually you had to order a hardtop yourself to get it. That's what I did.

The extra weight for the reinforcement and all that glass is high and forward, not where you want it in an autocross situation. Additionally, and gain, I'm not sure about 4th Gens, but 2nd and 3rd Gens with t-tops were a bit more 'flexible' than the hardtop versions. I don't think you can overcome that issue in ESP.

Weight difference is negligible in a 4th gen application. No chassis difference between the two. Pull down the headliner in a 4th gen sometime. The T top option was baked in.

Even if the glass tops did weigh more than a hardtop, how often do you really see anyone run with the tops in?

If the car was somehow more flexible as a T top, SFCs are legal in ESP

I think the Firebird actually has a bit more room in the wheel houses, so getting even more tire under the car, as opposed to a Camaro, may be possible. I'd get under the car and look around, though. 18" wheels may afford you more space to tuck more wheel and tire under the car. 18" wheels fit a lot better, especially under the front end, than a 17" wheel on a 3rd Gen. I know they have different front suspensions, especially up front, so you'll have to do some research yourself.

Maybe somewhat but 17x11s fit Camaros just fine. I've even seen 17x12s.

17 inch tires a bit cheaper than 18s.

Since Watts Links are legal (bolt-on only, IIRC), you may want to look into that to put on your mods list. They really help the 3rd Gens.

A Watts will make the car better no doubt, but IMO it really doesn't have to be high up on the list if on a budget. The cars were (and still are) plenty fast with a good ol' cheap panhard rod.

This post has been edited by Racer X: Mar 1 2014, 01:19 AM

[FlatBlack]

I can't post in the Classifieds.

Anyone have a 17x9.5 C4 Sawblade spare?

I bought a set of stock C4 wheels (17x8.5F and 17x9.5R) and then two 17x9.5 rears for $100. One of the 17x9.5s has a bend in the rim, and the wheel repair place wants $100 to properly fix the bend. Figured I'd just try to find a spare or wait around until someone has another set of C4 rear wheels for cheap.

Tax return came in, and I sold some 240SX parts. Should be placing an order for Konis and Strano springs soon (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

[trackbird]

I can't post in the Classifieds.

Anyone have a 17x9.5 C4 Sawblade spare?

I bought a set of stock C4 wheels (17x8.5F and 17x9.5R) and then two 17x9.5 rears for $100. One of the 17x9.5s has a bend in the rim, and the wheel repair place wants $100 to properly fix the bend. Figured I'd just try to find a spare or wait around until someone has another set of C4 rear wheels for cheap.

Tax return came in, and I sold some 240SX parts. Should be placing an order for Konis and Strano springs soon (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

I'm currently "sitting on" 4 sets of sawblades. 3 sets of them are painted (factory silver paint) and 1 set is the "machined" finish (I didn't realize a machined finish existed). I'm not sure they are worth enough to sell though. I have a set that was used for autocross use (still have some 2007 vintage race rubber on them). They are brake dusted and marked RF/LF/RR/LR on the outsides. That's likely the set I'd sell if I sold any.

You need one wheel or two? I'm afraid shipping would run more than I could actually get out of the wheels.

[FlatBlack]

I'm currently "sitting on" 4 sets of sawblades. 3 sets of them are painted (factory silver paint) and 1 set is the "machined" finish (I didn't realize a machined finish existed). I'm not sure they are worth enough to sell though. I have a set that was used for autocross use (still have some 2007 vintage race rubber on them). They are brake dusted and marked RF/LF/RR/LR on the outsides. That's likely the set I'd sell if I sold any.

You need one wheel or two? I'm afraid shipping would run more than I could actually get out of the wheels.

Just one, that would be awesome if you would sell it!

I have the machined faces, but I intend to paint them

I'm in Austin, TX

This post has been edited by FlatBlack: Mar 12 2014, 12:43 AM

[Racer X]

Anyone have a 17x9.5 C4 Sawblade spare?

Hmmm.... could've sworn someobdy just very recently hooked you up with a full set of 9.5 sawblades.

*shrug* Nah..... must be getting old. Surely you wouldn't be buying yet ANOTHER set this soon..... (IMG:http://www.frrax.com/rrforum/style_emoticons/default/tongue.gif)

This post has been edited by Racer X: Mar 12 2014, 12:46 AM

[FlatBlack]

Got my Koni Sports and Strano Springs on last night. I didn't listen to Korry and put the shocks on the lower perch. He'll find out here, so.. enjoy that.

The car really is a different car with proper shocks. I'm exited to get my front and rear bars and panhard bar on. After I raise the front up some, I'll work on the alignment.

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140317_183115.jpg)

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140317_233412.jpg)

*edit*

More parts arrived! These are solid, very happy with them. Thanks Alan! My end links should arrive today as well

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140318_113431.jpg)

This post has been edited by FlatBlack: Mar 18 2014, 04:39 PM

[Racer X]

put the shocks on the lower perch.

There is SO much I could type here but I'll just go with....

Why?

This post has been edited by Racer X: Mar 20 2014, 02:11 AM

[FlatBlack]

There is SO much I could type here but I'll just go with....

Why?

I figured your version of "too low" and my version of "too low" were different. It wasn't.

Fixed it. Reinforced brackets and new end links are on, I should be picking up my 35mm solid bar on Sunday, and my Panhardrod/rear bar get it tonight.

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140319_233818.jpg)

[FlatBlack]

Got the rear bar/end links and panhard rod on last night.

I was wondering - can I just pop the ABS fuse out to get rid of it, or will that give me serious issues like putting the ECU into limp mode?

This post has been edited by FlatBlack: Mar 24 2014, 01:33 PM

[79T/A]

No issues with pulling the fuse. I do it when racing then pop it in for the street.

[CrashTestDummy]

Man, unless the car has a nasty 'ice mode', I'd think ABS would be a good thing to have. I've used it to great effect when running our 96 SS or 10 PPV on street tires. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/2thumbs.gif)

[FlatBlack]

I"ll probably run with it for my first event and see how it goes, then try it with the fuse pulled.

I've been able to engage it on street tires, it makes the pedal feel terrible.

[trackbird]

Got the rear bar/end links and panhard rod on last night.

I was wondering - can I just pop the ABS fuse out to get rid of it, or will that give me serious issues like putting the ECU into limp mode?

No issues with pulling the fuse. I do it when racing then pop it in for the street.

The LS cars use the ABS module for rear proportioning. You may find that you have way too much rear brake after you pull the fuse. I always autocrossed with the ABS in place and working. You have to learn to drive "with" the ABS instead of "against" it, but it works ok once you do.

[79T/A]

It may have been because of a loose hub, but my abs seemed to activate prematurely, and like flat black said the pedal feels terrible, and it recovers slowly. I was able to brake harder without ABS on track. I always put the fuse back in for the street, nice having it there for emergencies.

[trackbird]

Usually it just aggrivates brake hop. Or that was what I remember. It's been a while.

[Racer X]

I've been able to engage it on street tires, it makes the pedal feel terrible.

That won't happen (or it will at least happen a lot less) on better tires.

Did you install the pads I gave you?

The LS cars use the ABS module for rear proportioning.

This.

[FlatBlack]

I've been able to engage it on street tires, it makes the pedal feel terrible.

That won't happen (or it will at least happen a lot less) on better tires.

Did you install the pads I gave you?

I haven't yet. I will have them on before the next autocross (well... after the Tour).

[FlatBlack]

The good thing about ugly/unpopular wheels is that they are cheap.

Found these on CL, had to snatch them up.

I always said that if I bought a C5 with wagon wheels, I'd get rid of the wheels first thing. After putting them on the Formula, I don't really hate them. I think they might look pretty bitchin in white. They'll be my street wheels.

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140405_222602.jpg)

This post has been edited by FlatBlack: Apr 6 2014, 05:50 PM

[Racer X]

Does that gas station attendant give you odd looks?

I mean you keep taking pictures of his pumps. He probably thinks you have some odd fetish or something.


And ummmm.... FYI

This post has been edited by Racer X: Apr 7 2014, 12:28 AM

[landstuhltaylor]

The good thing about ugly/unpopular wheels is that they are cheap.

Found these on CL, had to snatch them up.

I always said that if I bought a C5 with wagon wheels, I'd get rid of the wheels first thing. After putting them on the Formula, I don't really hate them. I think they might look pretty bitchin in white. They'll be my street wheels.

If you ever decide to get rid of them just find the local VW/Audi guys. They would love to buy them.

[FlatBlack]

If you ever decide to get rid of them just find the local VW/Audi guys. They would love to buy them.

The C5 Wagon Wheels?

VW/Audis are 5x112 or 5x100, and these are pretty low offset for FWDs

Does that gas station attendant give you odd looks?

And ummmm.... FYI

A: No

B: You're a bad listener. No 11s this year.

This post has been edited by FlatBlack: Apr 7 2014, 08:17 PM

[dailydriver]

The good thing about ugly/unpopular wheels is that they are cheap.

Found these on CL, had to snatch them up.

I always said that if I bought a C5 with wagon wheels, I'd get rid of the wheels first thing. After putting them on the Formula, I don't really hate them. I think they might look pretty bitchin in white. They'll be my street wheels.

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140405_222602.jpg)

They actually look much better on our rides than on the C5s they were stock on from the factory! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/2thumbs.gif)

[landstuhltaylor]

The C5 Wagon Wheels?

VW/Audis are 5x112 or 5x100, and these are pretty low offset for FWDs

That's never stopped them from putting Corvette wheels on anything. Why do you think anyone buys hub adapters?

(IMG:http://i186.photobucket.com/albums/x7/pbplaya426/DSCF1428.jpg)

[ReEntryRacer]

The good thing about ugly/unpopular wheels is that they are cheap.

Found these on CL, had to snatch them up.

I always said that if I bought a C5 with wagon wheels, I'd get rid of the wheels first thing. After putting them on the Formula, I don't really hate them. I think they might look pretty bitchin in white. They'll be my street wheels.

If you want a set of center caps for those, I have multiple sets. I think I have a set of chrome ones too.

Just pay the postage from BC!

[FlatBlack]

If you want a set of center caps for those, I have multiple sets. I think I have a set of chrome ones too.

Just pay the postage from BC!

I appreciate the offer! I have the center caps, but I think part of the reason I hated the wheels on the C5 is that the nut covers look really cheap/cheesy. I'm leaving mine off, plus the keyed nut is too long for the covers anyways.

Got my offset bushing upper arms and ST 32mm solid bar, hopefully getting those on tonight.

[FlatBlack]

Had my first race in the Firebird on Sunday, I was very pleased with it minus the damn diff. Need to get that fixed ASAP.

https://www.youtube.com/watch?v=x5yaCzDnH08

[FlatBlack]

Finally got pictures back from the Autocross. If anyone thought I was just making 'racer excuses' about my diff, just check out this picture:

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/20140426_1251.jpg)

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/20140426_1244.jpg)

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/20140426_1246.jpg)

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/20140426_1247.jpg)

[2MCHPWR]

what diff you going with? I think I want one too.
auburn
easton
tru trac
torsen T-2R

[FlatBlack]

what diff you going with? I think I want one too.
auburn
easton
tru trac
torsen T-2R

Oh, wow! Thought I had updated this thread...

I did the Eaton Clutch diff (Part #: ETN-19599-010 http://www.summitracing.com/int/parts/etn-...9-010/overview/ )

Night and day difference. I was blowing through rear tires, the new diff has reduced my tire wear significantly, and now I can put power down reliably and predictably.

Here's a video from my runs at Circuit of the Americas (Parking lot, not track)

http://youtu.be/BVeDphoJJrk

I got a pair of OEM C5Z Speedlines, hoping to get another pair for a matching set soon

(IMG:https://farm4.staticflickr.com/3835/14518475708_336f80d788_c.jpg)

Also, found out that my rear LCA bushings were shot and my torque arm was loose.

Replaced them with the upgraded Moog bushing that doesn't have voids.

(IMG:https://scontent-a-dfw.xx.fbcdn.net/hphotos-xpf1/t1.0-9/10563113_10103543921320295_840459820431649785_n.jpg)

This post has been edited by FlatBlack: Aug 5 2014, 04:16 PM

[2MCHPWR]

that is awesome. good to know. why did you choose the eaton over the other options?
did you have an auburn in there stock? i have 98 formula too (slicktop as you called it) so I think we'd both have auburns.
You still on stock LCA's and TA?

Can you run 315's on all 4 corners under stock fenders using 10.5 c5z06 rear wheels?

I'm jelly of your lowering springs. I'm on stock 1LE springs and its like a 4x4.

[79T/A]

Yes you can use the 315's on z06 wheels all 4 corners. Mark (camarokid91) has been running that set up this year. Had some of those sweet Pirelli world challenge rollers on it. Think you need a small spacer though when running a full set of rears on an f-body.

[FlatBlack]

that is awesome. good to know. why did you choose the eaton over the other options?
did you have an auburn in there stock? i have 98 formula too (slicktop as you called it) so I think we'd both have auburns.
You still on stock LCA's and TA?

Can you run 315's on all 4 corners under stock fenders using 10.5 c5z06 rear wheels?

I'm jelly of your lowering springs. I'm on stock 1LE springs and its like a 4x4.

A local C5 guy here is running 315s front (17x9.5) and 335s rear (18x10.5) on his car... but they have double wishbone rear and I'm told they have a better camber curve?I'll eventually move to an 11, but I'm not going to pay 315 $$$ to run it super stretched on a 9.5.

*edit* That's not what you were asking (sorry). Yeah, All of the ESP guys I know of run 315 A6s, but they are on 17" rims. I see no problem with running them on a 10.5, but you might need spacers. My 18x9.5 Wagon Wheels rub on the back, I have ARP studs and run a 1/2" spacer. They are 56mm offset

My previous region's ESP group went through most of the diffs, and the Eaton clutch diff is the one that holds up to 315 A6s on all 4 corners. The helicals and Auburn Racer's diff didn't last long. My car came with the "Zexel-Torsen" diff. It didn't work after 120,000 miles.

The Strano Springs/Konis/bars and rear diff made this car go from a floaty boat to a heavy-set athletic girl (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif) All the new people that walk up to me at Autocrosses seem amazed that the thing can turn corners, and I'm a midpack driver. I would really suggest getting the suspension kit if you can, it's worth it.

This post has been edited by FlatBlack: Aug 5 2014, 06:50 PM

[robz71lm7]

No chassis difference between the two. Pull down the headliner in a 4th gen sometime. The T top option was baked in.

Bull. This is an oft repeated myth. Look at the cross sectional area of the members connecting the A and B pillar.

Attached File(s)

 Picture179.jpg ( 55.96K ) Number of downloads: 54

 

[Blainefab]

No chassis difference between the two. Pull down the headliner in a 4th gen sometime. The T top option was baked in.

Bull. This is an oft repeated myth. Look at the cross sectional area of the members connecting the A and B pillar.

Rob is correct - the sheet metal in the Ttop roof structure is thicker than the hardtop.

[Beach Cruiser]

I run the Z06 rears all the way around with 315 rubber. In the rear I needed a 5/16 spacer and in the front I used a 1/4" spacer with ARP studs. I also have the upper control arm camber bushings. Strano/Koni and Strano's bars. I'm using an Auborn Diff. My car is usually in the top 20 in our region. I'm VA State Champion two times in ESP.

[2MCHPWR]

I run the Z06 rears all the way around with 315 rubber. In the rear I needed a 5/16 spacer and in the front I used a 1/4" spacer with ARP studs. I also have the upper control arm camber bushings. Strano/Koni and Strano's bars. I'm using an Auborn Diff. My car is usually in the top 20 in our region. I'm VA State Champion two times in ESP.

do you use a watts link and aftermarket torque arm? if so, which ones? how much does your car weigh? Do you think you'd do well against the turbo buggies in STU?

[camarokid91]

I run 315 Hooisers for SCCA and 305/660 + 305/680 Pirelli's for club all on C5Z wheels.

(IMG:http://i.imgur.com/xLzcuf5.jpg)

(IMG:http://i.imgur.com/TX9OogV.jpg)

[dailydriver]

My previous region's ESP group went through most of the diffs, and the Eaton clutch diff is the one that holds up to 315 A6s on all 4 corners. The helicals and Auburn Racer's diff didn't last long. My car came with the "Zexel-Torsen" diff. It didn't work after 120,000 miles.

Has anyone actually rebuilt the Eaton CF clutch pack Posis with the stronger springs available (800# I believe?) to run autocross/open tracking/etc.??

Or would that make them even worse than a locker as far as being too 'spool-like' for corner exits/slow apexes/etc.????

[FlatBlack]

My previous region's ESP group went through most of the diffs, and the Eaton clutch diff is the one that holds up to 315 A6s on all 4 corners. The helicals and Auburn Racer's diff didn't last long. My car came with the "Zexel-Torsen" diff. It didn't work after 120,000 miles.

Has anyone actually rebuilt the Eaton CF clutch pack Posis with the stronger springs available (800# I believe?) to run autocross/open tracking/etc.??

Or would that make them even worse than a locker as far as being too 'spool-like' for corner exits/slow apexes/etc.????

Racer X Has a rebuild kit for his, he might be able to talk on that some.

[FlatBlack]

Track day at Harris Hill Road yesterday, someone grabbed this pic (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

(IMG:https://farm6.staticflickr.com/5601/15457100881_973ff832c1_k.jpg)

Car's working really well. Headers going in this week

[Smitty2919]

I'm interested in all this differential talk. I need to get on over the winter for next season.

Flatblack, what was your reason for going with the Eaton clutch pack vs Eaton TrueTrac or even the Auburn Race diff with their rebuild program? How is it working out for you?

I'm only running 275 V710's on stock 10 spoke ss wheels and try to autocross as much as possible with the car being a DD. I have horrible RH turn pass rear tire spinning issues and can't power out of turns.

I like the rebuildable clutch pack/spring idea vs Auburn/helical gear design only offering their rebuild program for the first 4 years after initial purchase.

[ReEntryRacer]

I like the rebuildable clutch pack/spring idea vs Auburn/helical gear design only offering their rebuild program for the first 4 years after initial purchase.

Just a correction... the auburn does not use the helical gears, that's Torsen. Auburn uses bronze cones/springs. And they will keep replacing the diff. forever as long as each one is within 4 years of the build date stamped on it. I'm on my 3rd in 10 years.

[Smitty2919]

Ahh yes brain fart. I meant it as the torsen helical gears and auburn cone gears are not serviceable.

In terms of wear, you may only use your car for racing only maybe once a month and have had 3 diffs in 10years. I will DD mine seeing 10k mi if that per year and autocross once a month during autocross season.

Do you think DD a diff with monthy autocross needing replaced once a year?

[ReEntryRacer]

Ahh yes brain fart. I meant it as the torsen helical gears and auburn cone gears are not serviceable.

In terms of wear, you may only use your car for racing only maybe once a month and have had 3 diffs in 10years. I will DD mine seeing 10k mi if that per year and autocross once a month during autocross season.

Do you think DD a diff with monthy autocross needing replaced once a year?

I have an '01 Firehawk with original Torsen and 60,000 miles. It still leaves two black strips out of every corner, only serviced once, and it gets driven HARD.
The racecar with the Auburn was built and used for mini-enduro races of 1 hour or more, on my home track with most corners as tight as any AX course, but with fast entries to most corners.
I gave up on the Torsen in the first season of racing as it just did the 'one tire fire' all the time. The Auburns have stood up and worked well. The first one I folllowed the instructions and added the lubricity additive they send in the box. Bad idea for a race car, its quiet, but it slips too much. I filled it without synthetic or additive (Red Line HD) and got all the bite I needed.

Only caution is that Auburn will ask you to prove (send pic) that you will use their Racer's Diff. in your race car. I assume that means it will not last as long in a DD due to the higher bias.

[Smitty2919]

I have an '01 Firehawk with original Torsen and 60,000 miles. It still leaves two black strips out of every corner, only serviced once, and it gets driven HARD.
The racecar with the Auburn was built and used for mini-enduro races of 1 hour or more, on my home track with most corners as tight as any AX course, but with fast entries to most corners.
I gave up on the Torsen in the first season of racing as it just did the 'one tire fire' all the time. The Auburns have stood up and worked well. The first one I folllowed the instructions and added the lubricity additive they send in the box. Bad idea for a race car, its quiet, but it slips too much. I filled it without synthetic or additive (Red Line HD) and got all the bite I needed.

Only caution is that Auburn will ask you to prove (send pic) that you will use their Racer's Diff. in your race car. I assume that means it will not last as long in a DD due to the higher bias.

I have heard from others about not adding in the additive to the Auburn Diffs. How do you prove a car is a "race car"? Put stickers all over it? lol Do they frown upon replacing the diff if you put it in a DD? lol

[dailydriver]

Only caution is that Auburn will ask you to prove (send pic) that you will use their Racer's Diff. in your race car. I assume that means it will not last as long in a DD due to the higher bias.

I know this is a very subjective question, being that they are such dissimilar diffs, but does the Auburn Racer's diff seem to be at least the equal, as far as bias goes, to the T2R, or not??

This question is open to others who may have had BOTH, if you have never used a T2R.

[Smitty2919]

I thought I came across something saying the T2R was higher bias than Auburn....but since the Torsen's have/had quality issues etc does it even matter? lol

I would call a vendor of both and ask. Strano comes to mind of knowing since I believe he ran a T2R and went to Auburn due to the T2R quality issues and Torsen's inability to acknowledge the issue.

This post has been edited by Smitty2919: Oct 13 2014, 08:49 PM

[FlatBlack]

I'm interested in all this differential talk. I need to get on over the winter for next season.

Flatblack, what was your reason for going with the Eaton clutch pack vs Eaton TrueTrac or even the Auburn Race diff with their rebuild program? How is it working out for you?

I'm only running 275 V710's on stock 10 spoke ss wheels and try to autocross as much as possible with the car being a DD. I have horrible RH turn pass rear tire spinning issues and can't power out of turns.

I like the rebuildable clutch pack/spring idea vs Auburn/helical gear design only offering their rebuild program for the first 4 years after initial purchase.

From the last page:

My previous region's ESP group went through most of the diffs, and the Eaton clutch diff is the one that holds up to 315 A6s on all 4 corners. The helicals and Auburn Racer's diff didn't last long. My car came with the "Zexel-Torsen" diff. It didn't work after 120,000 miles.

So I've only had the Eaton clutch type, but 3-4 guys using the same axle came to the conclusion that it worked the best. From what I gather, I'm going to need to rebuild even the Eaton every other year or so, but it seems to hold up the longest on Hoosiers.

No complaints with mine, I actually had the inside rear chirp pulling out of a parking space the other day, so it's still working for sure. It has probably 1000+ miles and 80+ autocross runs on it by now.

[dailydriver]

When everyone rebuilds their Eaton Posi, do they just replace the carbon clutchpack with the same, or do they switch over to the 'old school' steel clutchpacks??

I take it that NO ONE is running the 800 lb. springs in theirs, correct?

[FlatBlack]

Lots of winter upgrades happened.

Installed TSP 1 7/8" Longtubes and a 3" Off Road Y-Pipe. Currently still using the stock exhaust from the I-Pipe back, but plan to dump at the axle. Hopefully later this year.

Got the Strano 35mm hollow bar, ended up being 5# lighter than the 32mm solid bar I had been running, and should be much stiffer. Also took some weight out buy pulling the A/C compressor/lines, radio/speakers, and air pump box. Was about 50# total.

Last but not least, I picked up Dave Ogburn's CCWs. They are 17x12 (he also gave me the 11" outers) with 335s on the front, and 315s on the rear. Can't wait to try these steam rollers out at the College Station Annex for the Texas Tour (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/Mobile%20Uploads/CYMERA_20150307_091057.jpg)

This post has been edited by FlatBlack: Mar 20 2015, 03:16 PM

[Steve91T]

You've got the wider tires up front?

[FlatBlack]

You've got the wider tires up front?

Yes

[ESP125]

Hello all,

Just picked up a 1998 Formula that I will be prepping for ESP class in SCCA Autocross. It's Blurple, but I don't care too much about my cars look (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

I have some other things to take care of first, but wheels (17x9 or 10+) and suspension should come soon. I plan on Koni yellows and GC coilovers.

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140226_175210.jpg)

(IMG:http://i254.photobucket.com/albums/hh81/flatblack280/CYMERA_20140226_175226.jpg)

I noticed you said you were looking to get some Koni coil overs. Would you be interested in a complete set from my 94 Camaro? They are Koni Sports (yellow), they were rebuilt/dynoed in 2013 (only have 30 events on them) Front part number is 8242 1005SP1 and rear part number is 8242 1006SP1. The car is set up for ESP as well and took 1st at Nationals (ladies class) and 8th (mens) in 2010.

[dailydriver]

No complaints with mine, I actually had the inside rear chirp pulling out of a parking space the other day, so it's still working for sure. It has probably 1000+ miles and 80+ autocross runs on it by now.

Are you using any limited slip friction modifier in yours (whether added in via 4 ounce bottle, or already in the gear oil)?

Also what type of gear oil (synthetic or mineral based)?

[FlatBlack]

I noticed you said you were looking to get some Koni coil overs. Would you be interested in a complete set from my 94 Camaro? They are Koni Sports (yellow), they were rebuilt/dynoed in 2013 (only have 30 events on them) Front part number is 8242 1005SP1 and rear part number is 8242 1006SP1. The car is set up for ESP as well and took 1st at Nationals (ladies class) and 8th (mens) in 2010.

I've already got Koni yellows, but thanks for the offer. I was mostly referencing the coilover sleeves/springs, not the shocks.

No complaints with mine, I actually had the inside rear chirp pulling out of a parking space the other day, so it's still working for sure. It has probably 1000+ miles and 80+ autocross runs on it by now.

Are you using any limited slip friction modifier in yours (whether added in via 4 ounce bottle, or already in the gear oil)?

Also what type of gear oil (synthetic or mineral based)?

IIRC the Eaton comes with a paper slip that says not to use LSD friction modifiers? Pretty sure I'm using synthetic gear oil. Honestly I'm not too sure, I've had about a million beers since then.

[dailydriver]

IIRC the Eaton comes with a paper slip that says not to use LSD friction modifiers? Pretty sure I'm using synthetic gear oil. Honestly I'm not too sure, I've had about a million beers since then.

Actually, they tell you to use the friction modifier (even though some who ONLY race the car do not, and live with the carbon clutch pack wear for the sake of better lockup/launch off of apexes), and NOT to use synthetic fluid in their Posi (and Truetracs for that matter) gear oils, even though most do with no ill effects.

Their Posi unit's carbon clutch packs would not last very long in daily street driving without the L.S. friction modifier, sadly. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/sad.gif)

[FlatBlack]

Actually, they tell you to use the friction modifier (even though some who ONLY race the car do not, and live with the carbon clutch pack wear for the sake of better lockup/launch off of apexes), and NOT to use synthetic fluid in their Posi (and Truetracs for that matter) gear oils, even though most do with no ill effects.

Their Posi unit's carbon clutch packs would not last very long in daily street driving without the L.S. friction modifier, sadly. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/sad.gif)

I've put ~2,000 miles on the car since I bought it February 2014. Most of that is highway mileage (i.e. not using the diff) to and from races.

It'll still chirp my street tires on tight turns (parking lot situations), so if it gives me better lockup, I'm all about it. Seems to be working just fine, the car was pretty miserable to race on the blown stock LSD.

[Jimbow]

When I first bought my case it would also chirp and sometimes bind up in tight parking spots or turning around.

I changed the fluid to Mobil 1 fluid and added about 2oz of ford lsd additive.

The ford stuff seems to work a little better than the other off the shelf additives, maybe because fords need some miracle additive??? Lol

[dailydriver]

^^^Yes, I also ONLY use the Motorcraft XL-3, or the Ford Racing labelled stuff.

I have been told that the Ford Racing stuff is actually a little better than the XL-3, and that it is NOT the same exact stuff, just in a differently labelled bottle with .20 of an ounce less content, but who knows? (IMG:http://www.frrax.com/rrforum/style_emoticons/default/gr_confused.gif)

I actually pay less for the FR stuff, so I don't care. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/wink.gif)

This post has been edited by dailydriver: Mar 28 2015, 01:49 AM

[Racer X]

You *want* the diff to be tight for what we do. As tight as possible IMO.

The spare I rebuilt and have on the shelf will either work really, really well or it will self destruct on its first run. I shimmed that sucker as tight as I could get it and still be able to reinstall the spiders. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/biggrin.gif)

And yes, Eaton specifies the LSD additive. The diff oil is the only place on the car where I DON'T use synthetic.

This post has been edited by Racer X: Mar 28 2015, 07:49 PM

[dailydriver]

^^^^But the 800# springs (in an Eaton Posi) would be too much for the street, and act like a locker on the track/a-x, correct??

This post has been edited by dailydriver: Mar 29 2015, 12:38 AM

[Racer X]

^^^^But the 800# springs (in an Eaton Posi) would be too much for the street, and act like a locker on the track/a-x, correct??

I've thought about trying heavier springs but after taking the diff apart and holding them in my hands, I seriously doubt the retainer plates would be up to the task.

I don't like wrenching on the car enough to be an R&D guinea pig. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/wink.gif)

This post has been edited by Racer X: Mar 29 2015, 05:14 PM