BDR rear end opinions please (BDR owners)

[pjmoore2003]

Rick thanks again, and you always give good advice.

Kevin, good luck, look forward to hearing how you like the rear later on.

[RodKnock]

Originally Posted by charlandk

While I have no intentions of ever selling this car, I believe that I will have more luck with resale if I were to have the LSD.

Hey, I think I said that over on your other thread.

[Gatorac]

I'm sure you'll be happy. Now on the hard decisions like what color.

[charlandk]

that part was not very difficult.

Sterling Gray with Silver stipes and thin raceway blue accent stripes on the outside of the silver. Not sure how to insert a picture of what it will look like.......

[Cashburn]

Concept...

[charlandk]

thanks Jay

[RodKnock]

Originally Posted by charlandk

that part was not very difficult.

Sterling Gray with Silver stipes and thin raceway blue accent stripes on the outside of the silver. Not sure how to insert a picture of what it will look like.......

That's pretty "ironical." Color choice is generally very difficult for most, including me, and the LSD is generally an automatic for most.

[Jimbocobra]

Picking that color combo is easy Oh, I have an open differential on my Sterling Grey and Silver Strip car and it works just fine on the street and strip. Listen to Jay on this one.

[spookypt]

Originally Posted by Cashburn

The Sebring video is a TD car that is not sold for street use, yes it has the LSD and a lot of other things for the track. Video also shows a French driver (note flag on helmet) and not Reg.
That's my theory...

Yes all true Cashy...... and it looks just lovely in my garage now! In my other cobras I run a semi locked diff as well but they aren't BD so I won't pass comment.

[mln385]

Well here is another take on it.... if a bdr handles so well with an open diff just think how well it handles with and LSD.


I am an advocate for the LSD.

[Cashburn]

Originally Posted by spookypt

Yes all true Cashy...... and it looks just lovely in my garage now! In my other cobras I run a semi locked diff as well but they aren't BD so I won't pass comment.

So you are the new keeper? I did not realize same person... good luck, to all the other racer Cobras in Australia now

[6t8stang]

I have a 450HP 351 with a T5 trans and 3.91 open rear. Never any problems with traction or kicking it sideways on demand. Every winter I thought about swapping the rear for a 3.91 LSD...still may do it, but I'm still very happy with what I have...

[spookypt]

Originally Posted by Cashburn

So you are the new keeper? I did not realize same person... good luck, to all the other racer Cobras in Australia now

Yeah mate...the goss is slowly bleeding out here in OZ.

Sorry for off topic hijack.

[Rwillia4]

sorry I did not read all of the responses...I wanted to skip the b!tching.

I have a 427W, T-56, M3 LSD and race springs. I think this is a pretty similar setup to what you are looking for. I can not comment on an open-diff. But with my LSD, I have had no problems with tracking around corners and never had the rear unpredictably kickout, never. When I want it to kickout it is easy to do and also VERY EASY to recover. It is so predictable I am thinking of going with bigger sway bars to stiffen it up a little more but I'm working on other upgrades (solid mounts for the engine, diff, x-member).
I (well at least use to) live in CA. The T-56 is great, highway speeds are normally 75mph, so the 6 gear with a 3.46 rear has worked well. ...yes I will be back in CA soon, gotta love the military life.

I didn't read how you were going to use it. I do both daily driver and SCCA.

[Ant]

Interesting topic and opinions.

My cobra although not a BDR is a UK version RamSC I have fitted a 675bhp nascar based alloy engine with race box etc, and all the good AP brakes, 8.8 irs with Eaton carbon posi and on it goes, there isnt a decision on whether I should run an open diff or LSD because an open diff wouldnt cut the mustard, the decision is more like either LSD, locker or a spooled diff. All the cars I have driven with an open diff I have soon found the inside wheel generally breaks loose with loss of traction.

I am no M Schumaker, and probably most of you BDR drivers with BMW rear end and good suspension design makes good use of an open diff which is fine for most drivers, but for serious horsepower and track use the open diff is a waste of time period, you dont see race cars with open diffs unless they were little light Lotus type of cars of the 1960's which never seemed to really need a LSD!

Interestingly enough back a few years when I had a Bathurst Monaro and a friend had a Falcon XA GT 351 both had LSD and on a wet off cambered road these cars could easily catch out the inexperienced drivers when you gave them a heap of gas which could result in a spin or tank slapper, they didnt have good steering either....!

I do apologise for giving a non BDR opinion but I am bored and have posted for a while.

[Dinobyte]

No matter which rearend...with the power you say your motor will be making, make sure you beef up the differential support. The BDR TD cars come with something already, and there are aftermarket kits for it.

Here is one...http://www.aatuning.com/viewproduct.aspx?id=Product42

I have run into three separate folks here in SoCal that have had this issue, where the support bolt snaps. For the record, all of them had the larger bolt in there differentials.

As for Gearing...I would not recommend going higher than 3.46. Great gear for quick burst and for highway driving.

[Blittleton]

Originally Posted by Excaliber

Never said they were a bad car. I doubt there are any BDR's competitively running a road course with an open diff, Gator included. I seriously doubt there are any BDR's running under 12 seconds in the 1/4 with an open diff and street tires (personally I run in the 11's, with street tires). Traction, across the board, for ALL Cobras is the number one limiting factor when it comes to performance, accelleration or cornering.

For the best performance it's just a no brainer, you need an LSD of some kind. If your mostly street driving, going in a straight line, not seriously running SCCA events, are happy with a mid 12 or low 13 second quarter mile time on street tires or willing to run slicks (I wouldn't on the street) then an open diff may work well for you.

While it may be safer in the short term, I question how safe it might be in the long term? When you get used to the car and start to push the envelope and the rear end steps out, will you know how to handle it? How will you learn? I think a good drifting session is a great way to figure that out. Do it on wet pavement, low speed, in a big parking lot, but do it BEFORE it happens on the street, with other cars all around you.

excaliber,

Ihave customer that ran a 11.4 1/4 mile. Actually he has ran this a couple times. And yes with an open rear.

Bill

[Sledge]

Dinobyte: is installinng the aatuning support as easy as it looks? I have the standard suspension (not M3). I understand there are other supports out there as well, and a couple of friends have been describing home made braces for the two small unused lugs on the underside of the diff. Seems to me the aatuning support would perform a very similar function.

Thanks

[pjmoore2003]

Originally Posted by Blittleton

excaliber,

Ihave customer that ran a 11.4 1/4 mile. Actually he has ran this a couple times. And yes with an open rear.

Bill

Which engine did he have??

Phil

[Excaliber]

Bill, 1/4 mile is a straight line. I just got home from running a road course today, very tight and twisty. You could easily spot the cars with and without LSD's. Extreme cornering lifts up the inside tire which promptly goes up in smoke. Now perhaps with the right suspension setup on a BDR body roll would be minimum, even under extreme cornering so inside wheel spin could be limited. But for road racing, I'd go with LSD every time in every car.