Is there any kind of positive traction or limited slip differential available for the XF?



I test drove an SRT6 the other day and left the traction control on and the XF took a nosedive when the tire broke loose. I turned off the traction control and just smoked the right rear tire. With people adding mods to the engine and increasing HP to 400+ it needs positive traction or limited slip for any kind of a decent launch.

 

Wayne 1992, You made a very valid point. With "mods" the SRT-6 probably does need "Posi" to actually realize any benefits the added H.P. supplies. At least in a 1/4 mile contest, when "hooking up" is imperative for a good launch, and the lowest E.T. possible. But I wonder if much or any improvement would be seen on a stock SRT with posi?

Now since I've never driven an SRT-6, I'm probably not the best person to be commenting on them, but from what I've read the fastest 1/4 mile E.T. I've seen in print for the SRT is 13.3 sec. With 330 h.p. an automatic, 3:27 final drive ratio, and factoring in the Crossfires weight, that's just about what it should be turning. Which isn't bad. Especially when the same magazine only got a 400 h.p. Vette to do 13.2. Sure it weighs more, but the 2 extra cylinders should have more than made up for it.

Some cars need a little "wheel spin" to keep from "bogging" when coming out of the hole, some don't. Personally, I don't know if the SRT is one of those cars or not.

All I know is, the very quickest 1/4 mile E.T. I ever turned in my 37 year old muscle car, was the runs I made with absolutely no wheel spin at all. It didn't bog, the back end just squatted down, the nose went up, and it left the line with no drama. Not very impressive to the spectators, but it got the job done with my best time ever.

So SRT owners, which is it. I know that some of you have "hammered" your cars while launching from a traffic light. Sometimes you hook up and hardly brake the tires loose, other times you smoke em. When you hooked up, did your car bog at all, or did it just dig in and pull like a freight train?

 

I'm kinda confused, all of the marketing material I've read over the past couple years says that the Crossfire has a limited slip diff. But, the other day I received the engineering specs. from DC and they say it is an "open" diff.

I was surprised when I saw the specs. from DC engineering...

 

I hammered it from a dead stop and it rolled out about ten or 15 feet before it built enough boost to spin the tire. There was no bog or anything out of the ordinary. At the drag strip with VHT down the track will be sticky maybe enough to maintain traction but with any more HP it will certainly break loose anyway.

I really think limited slip should have been an option.

 

Thanks Wayne, I've only driven a SLK Kompressor, and needless to say I was unimpressed. Thanks for giving me a better description on how you launched it. I was curious, because even a Viper will bog if you dump the clutch to soon thanks to its gigantic tires, and 3:08 rear end, but go just a little to far over a certain RPM, and all you do is fry em.
That's why I've always preferred an automatic over manual when drag racing. It's just easier to pull a hole shot on the other guy driving a stick.
I bet it would be really big bucks to get a posi unit set up for a SRT-6.

 

Actually, the fact that you can't get a posi unit turned me against spending the extra bucks for an SRT6. I would think you could probably get a posi somewhere but I don't know enough about Mercedes to find out where or how.

The XF is fun to look at and fun to drive. I even like the way it hits a chuck hole - solid if you know what I mean. The darn thing rides smooth for a small car. I think I will continue to race and modify the Vette and just enjoy XF as it is. But, my mind changes like the wind!

 

Wayne, what year Vette, and what kind of racing do you do? Just for the record.

 

I usually have to go about 3/4 throttle from a dead start to get a good launch. Too, I
have to say there has never been a problem with bogging out. Take the foot off the
brake and smash the gas, it just goes like a banshee. But a little too much gas and
you'll spin the tires and maybe fish out to the left a little before it bites down good.
24,000+ miles and seems to have lost nothing.

Coyote

 

berg werks made one for merc. but they are out of business. darn shame as they made gears too.
startech has one on there site. good luck getting one.

 

I've been a drag racer for years racing motorcycles and cars.

I have a '92 Vette with extensive streetable mods. I'm one of those people that prefer a straightaway to a turn but I'm beginning to appreciate a turn more since I got the XF.

• CNC heads and cam package
• full roller assembly
• under-drive pulleys
• 58mm TB
• cold air/ram air/air box
• Accel ignition
• 3000 stall torque converter
• Dana 44 conversion with 3.73 gears
• Tri-flo full SS 3" system

Check out my site. I no longer maintain it but the pics are still there.

http://home.alltel.net/wayne/

 

If you want an LSD they are available for the SLK32. Kleeman, MKB and possible Quaife (unproven fitment).

 

The Quaife will fit a SLK32 so there should be no reason it won't work on the SRT-6. Nice thing about them is if bought thru Quaife, it's a lifetime warranty (will no exception if the vehicle is used in competition).

 

Boy do I feel stupid, talk about an old "amateur" trying to tell a current "pro" a thing or two about drag racing. Thanks for humoring me.
Cars like your Vette, and guys (in the know) like you, are the #1 reason I choose not to race anybody with my "stock" Viper. It's always the "sleepers" like your Vette that cause the most embarrassment.
Are we talking 11's with your Vette?
What kind of "scooters"?

 

Believe it or not in "Hawaii's fastest street car shootout" the supercharged Viper only took 4th...lost to a turbo VR6 GTI (3rd), 1,000 HP TT Supra w/nos (2nd) and a Toyota Carina with a SBC...talk about a sleeper!!! Full blown Small Block Chevy in something smaller than a Vega!

~ Jess

 

Yes sir, 11.92 @ 119 mph @ 39 degrees F with drag radials. One draw back though is the fact that I have put four rear ends in it.

I'd love to have a VIPER! Actually I have been looking at an SRT10 truck. One bad as* truck!

 

I figured you had to be in the 11's with your mods. I'd love to have a 3:73 gear in my Viper, but since I don't drag race it I figure what's the use? The 3:08's that come stock are just to "high" for any kind of USA style driving. I mean where are you going to run 190 at without losing your license. On the other hand, I wish our Crossfires had 3:55's instead of the 3:27's. But with the 1st. gear being so low in our 6 spds. you would have to shift out of 1 st. gear before you got to 15 mph. Might work in the automatics though.
Just out of curiosity, what kind of bikes do you race, and what kind of times do you turn?

 

When I was a kid (crazy kid) I drag raced a 1973 DENCO 500 Kaw. It was not fast by today’s standards but was one of the fastest in its day. I bought the bike in 1974 and sold it 1996. I was not a good bike rider but it was cheap speed.

 

As far as I know (knew?) fitment is (was) unproven. There is an outstanding question about the rear differential size and the Quaife fitment.