Backdraft Drivetrain

[Tico]

After a few months of research I am seriously considering a Backdraft Cobra. As far as the engine, I would like a Roush 427R or a Keith Craft Racing 427W - but I saw this on another thread and wondered if the statement has any truth to it (concerning the drivetrain):

"If you are considering the Backdraft and a Roush then buy a Superformance and anyone's engine and you will be better off for the same money. But based on the specs I've seen, I don't think the BDR drivetrain is up to a Roush 427R. So why spend the money just to break the drivetrain? Add the Roush to a Superformance and you have a killer combo that adds long term value."

Does anyone here have a 351W stroked to 427 in their Backdraft? If so, have you had any problems with the BMW rear end?

Thanks in advance.

[Gatorac]

Your going to have to find a pretty cheap engine to make up the $10k plus difference in price.

I haven't heard of anyone breaking the diff yet.

Since your in Orlando, are you coming to the Roundup? You can see the cars and owners in person. There will be examples from just about every manufacturer there.

[DC COBRA]

TICO

Yes I have a 427W in my Backdraft, She makes over 612 on horsepower and 615 on torque. I have the standard E36 BMW drivetrain in my car. Sort of being a guinea pig in a way, I have been trying test the limits to the point of breakage, along the way feeding info back to REG and TONY of Backdraft Racing. So far no luck as to breakage. After doing some reseach with some BMW racers and other technical people and "testing" of my own, these rear-ends are a hell of lot stronger than people will give them credit for.

DON

[Dennis Kelley]

No one may have broke the differential in one of these cars (BDR), BUT the one wheel peel is standard and will drive you crazy. This is the first car that I have had that does not have limited slip. I'm pricing limited slip and its anywhere from 500.00used to 1900.00 new. thats with me installing it. I cannot get a little 302 to lauch with it so with a stroker windsor's torque you will go nowhere fast. It will make for a great one wheel burnout though. Did I tell you I hate the rearend and it does not belong in a performance car. Upgrade to limited slip before you pick the engine, Dont make the mistake of buying the standard differential. Just my opinion.

[Gatorac]

Originally posted by Dennis Kelley


No one may have broke the differential in one of these cars (BDR), BUT the one wheel peel is standard and will drive you crazy. This is the first car that I have had that does not have limited slip. I'm pricing limited slip and its anywhere from 500.00used to 1900.00 new. thats with me installing it. I cannot get a little 302 to lauch with it so with a stroker windsor's torque you will go nowhere fast. It will make for a great one wheel burnout though. Did I tell you I hate the rearend and it does not belong in a performance car. Upgrade to limited slip before you pick the engine, Dont make the mistake of buying the standard differential. Just my opinion.

What tires are you running? I went with the 17" wheels with the Nitto DR's. I have a 408 SB @475hp. Traction is not an issue. (To my surprise.) WOT in 2nd gear with no spin. This thing sticks better the my FFR with a 302 (traction lok diff and crappy tires). The 15" standard wheel/tire package will suck. Especially with an open diff.

Any kind of posi diff for the E36 doesn't come cheap.

[Dennis Kelley]

I'm running the 15 inch wheel and tire package and its spin city. Gatorac what are your 60 foot times? The best I have done is a 2.1 but mostly 2.2 is the norm. Where did you get your wheels. Ive never run DRs how are they on the street?

[Tico]

Originally posted by Gatorac


Since your in Orlando, are you coming to the Roundup? You can see the cars and owners in person. There will be examples from just about every manufacturer there.

I will be away on a business trip to Guadalajara, Mexico, from November 11th to November 20th - so unfortunately I will miss the Reptile Roundup. However, I did buy five tickets to hopefully win the Backdraft roller.

Since I will miss the Roundup (which would have been ideal to check out several manufacturers in one day) I have been slowly but surely trying to do my homework. Last month I visited Backdraft (Reg and Frank) in Boynton Beach, Florida, and Blue Moon Motorsports (Factory Five dealer and builder) here in Orlando. Last week I visited Shamrock Autocraft in Chattanooga, Tennessee, and also McMichael Motorsports (Superformance Dealer) in Braselton, Georgia.

[chuckmynatt]

I also believe the BMW diff's to be much stronger than people give them credit for. These cars are so light that it's hard to place a huge load on the drivetrain anyway. Having said that I wouldn't build a full-blown drag car using a BMW e36 IRS either! Drag race-style launches are not good with any type of IRS. The only area I might look at upgrading is the half shafts. With the 427R motor I would upgrade to the M3 half-shafts.

My 2 cents

Chuck

[Lizard_King]

I have a Backdraft, with a Keith Craft 351w stroked to a 408, 580 hp, 565 pounds of torque, 750 mile new on the car. I upgraded the suspension and brake system to the M3-series, what a differance. I also put a 3.73 rear vers the stock 3.10. I get on her from time to time, and she has not missed a beat, Reg and the crew really know there cars well! I belive the Backdraft has a heads up on the Superformance as far as price goes, you can't beat the Backdraft!!!!!!

[Gatorac]

Originally posted by Dennis Kelley


I'm running the 15 inch wheel and tire package and its spin city. Gatorac what are your 60 foot times? The best I have done is a 2.1 but mostly 2.2 is the norm. Where did you get your wheels. Ive never run DRs how are they on the street?

I have the 17" package from BDR. It's a $1000 option and comes with the 315 Nitto DR's. We ran these on my wifes daily driver for a while. They are fine on the street. They are not ideal for the rain.

No 60ft times to report yet.

[Tico]

Originally posted by Dennis Kelley


No one may have broke the differential in one of these cars (BDR), BUT the one wheel peel is standard and will drive you crazy. This is the first car that I have had that does not have limited slip. I'm pricing limited slip and its anywhere from 500.00used to 1900.00 new. thats with me installing it. I cannot get a little 302 to lauch with it so with a stroker windsor's torque you will go nowhere fast. It will make for a great one wheel burnout though. Did I tell you I hate the rearend and it does not belong in a performance car. Upgrade to limited slip before you pick the engine, Dont make the mistake of buying the standard differential. Just my opinion.

Would the upgrade to the BMW M3 suspension correct the limited slip situation (one-wheel burnout)? That's a $4,000 option for the sport suspension (which includes the 17" wheels and tires). This option, added to the options I want on the car, would put the price only $5,900 below the Superformance 10th Anniversary Edition ($41,900).

[Dennis Kelley]

Choose your poison Tico. I love my BDR but I'm not happy with the one wheel peel. that M3 upgrade is expense. If your just driving the car to look good don't worry about limited slip. If you plan on Any competition you better get limited slip. I thing if you add M3 option, conv top, heater, the price differecne between BDR and SPF is minimal. compare apples to apples. This is just my opinion the SPF come standard with a lot of equipment that is options on the BDR. Their both graeat cars I just can't afford 40K all at once.

[CSCHWER]

I replaced the open differential in my BDR with a LS unit and what a difference! Any Cobra without LS is helpless when the wheel(s) are spinning. You can pick up the LS Diffs used for a reasonable price. The price seems to depend on the ratio your looking for. I picked up a 3.91 LS for $140.00. The mid-ratios seem to go for $300 to $600. Rebuilt about $1600.

Chet

[Dennis Kelley]

CSCHWER

Tell me where you picked up your used Differential. I need one bad its my winter project if my wife doesn't divorce me and make me homeless.

[CSCHWER]

Dennis,

Watch E-bay. Look at the Bimmer Forums. Like I said, depends on the ratio you want. www.diffsonline.com has used and rebuilt diffs in most ratios, rebuilt and used. Diffsonline can rebuild in just about any lockup you want for $ 1400-1600 exchange.

Chet

[Dennis Kelley]

Thanks chet,

looks like i found a diff.

[Boudy]

Hi Tico: These guys are petty much dead on. We have not had a failure yet due to HP/TQ issues. There have been some minor failures, of course, but none indicating weakness on the drive train.

As for the M3 package, really nice and worth the money if it's what you want. I does require 17's to house the brakes which some guys don't like. The brakes are really the best assett of the M3 package. If you were to consider an upgrade to handle drag slicks, for example, DC COBRA can tell you where to find half shaft upgrades for less than $1,000. You can't just change to M3 shafts alone, things won't fit.

All in all, I assure you that you won't twist a shaft with 15" T/A's and a 2300 lb car.

As for buying a Superformance, that debate will never end. There's a car for everyone so just buy what works for you.

Boudy

[Tico]

Originally posted by Boudy


As for the M3 package, really nice and worth the money if it's what you want. I does require 17's to house the brakes which some guys don't like. The brakes are really the best assett of the M3 package.

Gentlemen, thanks for all of the replies. However, I am still a little confused. If I upgrade to the M3 suspension will that eliminate the "one wheel burnout"? In other words, will BOTH rear tires spin?

Surely Backdraft must be searching for a fix to this problem without requiring their clients to upgrade suspension, right?

Thanks.

[Dennis Kelley]

You don't have to upgrade to a M3 suspension but you can buy a E36 limited slip diff and put in your standard suspension car. If you like to do things yourself buy the car and change the diff in the driveway. You can do it yourself I took the diff in my car out to install a new driveshaft. Its simple but a limited slip diff is expense as has been explained. I'm just trying to find one for the right price but I feel that a good stock one can be had for 600.00. Just buy either car and take it out and beat on it until you find something you don't like and fix it and tell us all about it. I don't think you can break the diff in a backdraft standard or Limited slip. repeat after me "I promise to beat the S!!t out of either car I buy I PROMISE.

[CSCHWER]

Hey Dennis,

What ratio did you get?

Chet