advice: 02 diff to handle 600 hp

[ehegwer]

how 'bout a few photos then. I'd love to see the monster you are trying to tame.

[codigoRojo]

Thanks for the feedback everyone. I like the idea of running a vette rear end, and probably a dana 44 could handle it. It might even fit my budget, but once I start tweaking it (i.e. narrow it) it'll go way over. I already know I can do a nice ford 9" with floating axles, coilovers and whatever suspension link design I want within my desired price range. The unsprung weight kinda bugs me, but durability is irrefutable. So is gear selection. I also thought about a quick-change rear end like out of a sprint car. Those can get spendy though too. Light though.

As for the "half-assed planning" remarks, you talkin to me? I'm only asking about rear end options that the 02 community might have some experience with that I haven't thought of. The car is tube framed and the rest of the drivetrain is bulletproof. No, you may not take it for a drive.

-Rojo

[tjones02]

email Rob at 2002 HAUS 2002haussales@gmail.com Ask about the rear differential conversion

Ok, so the 2002Haus subframe can mount the "mid case" diffs from an E30 but the mounting bolt pattern of those diffs are the same for the E23 7-series and E28 M5 and other early "Big case" BMW diffs......... The big case diffs might be able to handle the power...

The case in these E34's mounts different but the R&P's are the same.... 1200hp E34 M5....

[Preyupy]

Sorry did not mean it as any kind of dig on you. Just thinking about all of the things that have to be thought of when you start a project like this. What class are you going to run EM?

[Guest]

Heck, weren't the Group 5 turbo cars only in the low 400 HP range? I'd say those were modified "a bit" to handle that power.

Boost dependent, between 450 and 650 according to the FS here. http://www.race-cars.com/carsold/bmw/1053033333/1053033333ss.htm

I second the "big case" diff, medium case wouldn't cut it. Go ask on bimmerforums, some of the e30 guys are making 500-600 and I'm sure they can answer the question of what breaks first.

[amdavidson]

The car is tube framed and the rest of the drivetrain is bulletproof.

Pics or it didn't happen ;-)

[ClayW]

And I don't want to spend more than $1-2k for the whole rear end and suspension setup.

Rojo

$1-2K for an IRS that can handle 600hp sounds a little tight. You can get a stock E30 medium case diff with 2002 Haus's rear subframe and axles and stay within your price range, but you're probably going to have to open the checkbook a little wider to get stub axles and hubs that can handle that kind of power.

[TobyB]

As for the "half-assed planning" remarks, you talkin to me? I'm only asking about rear end options that the 02 community might have some experience with that I haven't thought of. The car is tube framed and the rest of the drivetrain is bulletproof. No, you may not take it for a drive.

..and there you go. Nothing offered, little gained. You show up with no

pictures and numbers that don't make sense for a 2002, no real history

of build posts that I'm aware of, and sure, we're not going to take you very

seriously. Bulletproof. Ok. How? What?

A little history, a pic or 3, and you'd be surprised at how much

'something offered' might get you in return- 'something gained.'

Heck, or even a back story...

jus' sayin'.

t

been here a while...

[Ken]

This was pulled from the E30 tech forum. You can find a lot of information on that site as well as other E30 forums

09-19-2009, 07:13 PM

Senior Member

Its torque that kills em fella. But there are lots of E30's punching well over 600HP on the stock medium frame diff.

__________________

If you are going to use a Ford 9" differential you should start with a Ford Falcon.

[tim385]

Ya got to get that HP to the ground and be able to use it ...too much is a waster of time and money , My lotus 7 has got 230 hp car weighs 470kg 4;11 LSD It was quicker with 40 hp less as now it just lights em up....admittedly its good fun ......mind bending accell.....HP aint the be all end all .

[Tommy]

I would build it around the e30/e28 188=middle case diff as suggested. It's proofed that it can handle those figures. Because of width custom shafts are required but if you build the subframe by yourself the budget could be ok.

Don't ruin your BMW with straight axle unless you only want to drag race.

Tommy

[thorgan]

Have you thought of using the IRS out of a Ford Thunderbird or Lincoln Mark VIII? Both are based off of the Ford 8.8" center section which, although not as strong as a Ford 9", they are definitely stronger than the Dana 44 diff in the 'Vette rear. This is the IRS that the Factory Five Cobra kit cars use and they're regularly putting down the kind of hp and torque numbers you're talking about. Furthermore, the Lincoln units used an aluminum diff housing for a little bit of weight savings.

This is the unit that I'm using in my '02 project and, to fit the wheels and tires I'm planning, I'm going to have to narrow it about 10" and put mini tubs in the car. I'm not looking forward to fabbing the control arms.

I also like this rear end because it's a true unequal-length double A-arm system and I expect it to handle better than the stock geometry.

I picked up the one I'm using for only $300 from a guy who was parting out a Mark VIII.

[Lee]

The medium case e30 diff is the same as the e28 diff, except for the rear cover. That diff was able to widthstand the euro M5's 290hp for a lifetime. Therefore that same diff will be able to sustain 600hp, providing you maintain it and check it out from time to time. The subframe will have to be a solid mounted e30 subframe, with pins going thru the trunk.

The differential is not the weak link. You will need to make custom halfshafts, and change them often. After all, at that level of power, every simgle element will need frequent inspection. But honestly, while you are there, I am pretty sure that you don not intend to buy an off-the-shelf conversion and have the ability to produce your custom set-up.

Lee

[tjones02]

The medium case e30 diff is the same as the e28 diff, except for the rear cover. That diff was able to widthstand the euro M5's 290hp for a lifetime.

The E28 M5 used the big case diffs, not medium.....

[Lee]

Was the e28 M5 diff. different from the 535i diff?

I had a bunch of Euro e28 diff that I sold and got installed on e30 M3s.