So I've been autocrossing with the stock 25mm front swaybar for 5 years. Over the years I have seen several pictures of my car and felt the rear-inside wheel lifting & slipping during sweepers. According to Fred Puhn, this is a classic symptom of an insufficient front "anti-roll" bar. So I dialed up a heavier sway bar in GT6, and in the simulator the Crossfire felt better in turns. So I ordered a Front 30mm H&R from ECS Tuning for about $250. According to Fred's calculations going from 25 to 30mm is just under 100% stiffer. So I installed it and took it out to the track for an autocross event that had 3 Epic Sweepers (I was in third gear for two of them) and the H&R really flattened the car out in the turns. In addition to the sway bar upgrade, I did lower the rear about 1/2" and was running new 245 A7s up front and 295 A6s in the rear, so there was some additional improvements, but the H&R was a big help. I didn't seem to generate any more understeer, but that may be simply offset by the new tires. One of the faster Z06's used to be faster than me by 3-4 seconds in a 60 sec event, and he was only about 1.5 sec faster yesterday (fortunately he is 3 classes ahead of me). I will monitor it throughout the race season. For the money, I would recommend it to anyone wanting to autocross competitively.
Mike

 

That's a huge improvement. I've been thinking about the H&R sway bar myself. Perhaps it's time to stop thinking and just buy it.

Les

 

Wes
The front bar keeps the front outside tire from dipping and the rear inside tire from lifting. See if you have an issue with that. For me, I liked the way the car handled in all other aspects of transition, but I finally had enough evidence to fix that performance gap.

Hope your R7s are working well. My A7s really warmed up fast, and the mega-sweepers that were set up almost overheated them in 5 runs (few cars, lots of runs). TireRack says they will last longer than R6/A6, but taking care of them (psi, temp, alignment) is a must.
Mike

 

My biggest issue is putting the power down on corner exit, even with the wavetrac. I'm going to buy one for myself to find out what it does and doesn't do.

Les

 

I'm getting ready to install a factory front sway bar from a 2003 SLK32AMG. It's a lot bigger in diameter than a SRT-6 front sway bar except for the very ends. It still uses our same u shaped mounting brackets. To achieve this,the MB rubber bushings are a smaller wall thickness than ours. Squirrel Crusher

 

It's funny this topic came up. I was just talking to someone this weekend about set up and we were talking about bars. It was at that moment that I realized we have a bigger front bar but haven't installed it yet. Les this should help with the inside rear traction issue. in theory it should put more pressure in the rear inside wheel and relive pressure from the inside front wheel. It will require a fresh corner balance to get the understeer out. I'll get it installed sometime next week or the week after and got to testing. I'll keep you posted!

 

If I'm not mistaken, the H&R bar is an upgrade of the SLK32AMG bar.

Les

 

I'm thinking this is a good idea. Since the OP was not SRT6, I'll look forward to your report Les as I also have the Wavetrac and still oversteer on exits. thanks for the ideas!

 

After reading a long thread on how to fix an oversteer condition on a rwd .... Lets just say my method with toe in and limited rear camber was called lots of things but not the right way to fix it. The race car parts sellers and racers recommended a bigger front bar to start with and adjust from there. The car in question (BRZ) was good on entry and balanced mid corner like my car is. If I could put the hammer down on exit …… good gosh man ……. so ….. I'll order the bar when I get back from vacation.

Les

 

where does someone who lives in paradise go on vacation?

 

Portugal river cruise and then Madrid! Perhaps I'll order the bar from some exotic place. More special that way.

Les

 

aha! Yes, Portugal is awesome. Enjoy

 

Les are you having oversteer issues? Did you recently raise the rear of the car? What are your camber and toe numbers?

 

Just a heads up, the A7 and R7 require alot more pressure in them, like 44 to 46 hot. Hoosier changed the side wall construction from the 6's.

 

I'm running the A7's up front starting at 40 psi cold. I figure as long as it doesn't feel like I'm skating, I'll let the pressure rise and see when it falls off. It was up around 45 last weekend before I bled it back to about 40. I'll let it go higher until my times fall off. I wouldn't mind the firmer sidewall over the A6's.
Mike

 

Logically a lifting & slipping inside rear wheel would a classic symptom of an insufficient rear anti-roll bar.
Why not go with a larger rear anti-roll bar? It would cut down on rear roll obviously, keeping more weight on the lifting & slipping inside rear tire, keeping the rear (and whole) of the car flatter.
Which ever end of the car has the stiffest anti-roll characteristic will lose traction first.

 

A larger rear sway bar in the Crossfire's case is not just necessarily a "bolt on ".
There has been sufficient documented evidence that the stock bar is capable of tearing out it's body mounts.
If I were installing a heavier bar, I would seriously investigate reinforcing the two body mounting areas.

 

Is see the "tearing out its body mounts" issue as more of an anomaly (a production manufacturing problem on relatively few car) than an issue that affects all Crossfires. Either way a stiffer rear anti-roll bar would help the lifting-spinning inside rear tire issue. That said, it probably would be a good idea to beef up those problematic mounts if using a bigger rear bar.

 

Where does one purchase these upgraded swaybars?

 

2003 Mercedes Benz SLK320 Base V6 3.2L Suspension Sway Bar - ECS Tuning