F111F

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Hey Dan, I have a question on suspensions and maybe general advice.

Background:
I have a 350 w/ sport suspension. At Texas World Speedway, coming of the high speed front stretch, my rear suspension would completely compress, bottoming out the rear suspension, unsettling the car slightly (at ~100+ mph, this can be very unsettling). This is the same course Easty has on his video. On the other hand, on tight cornering/acceleration my SLK350 could outperform a lot of the smaller cars (Miata's/S2000/Evo's) which is great since my HP wins out on the straight passing zones (except for that evil turboed Evo), and of course I completely harass the Z06's in corners.

Instructor with me had a lot of driving experience (former SCCA champion in a Supra-Turbo, and former instructor for PCA), recommended more dampening and maybe slighty more camber (not enough to wear the tires unevenly, but to support turn-ins better). In the same group was an experience solo driver running an SLK55, which seemed to perform great on the track (blew by me on the high speed front stretch).

So.....

Question 1a: What would you recommend for suspension upgrade?

1. AMG Suspension,
2. Bilstein Active Suspension,
3. Tein Active Suspension,
4. MB Black Series?

Question 1b: Upgrade to an SLK55, because cost would be about the same and the SLK55 is not going to be passed on a high speed straight very easily by a Z06?

Input and opinion are appreciated, I am not looking for exact answer some insight on what direction to go before sinking a lot of money.



P.S. Of course, if I had lots of money I would go for the SLK55 black series.



http://www.tuningmag.net/?name=merce...edition-tuning

DansSlk

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If i where in your place i would go for a proper system ideally active damping so you can tune it much better.

The AMG system is good but ultimately like everything that gets produced today is a compromise a system with fixed rates that has to cope with normal day to day driving and harder track use with more bias toward the day to day, an active system would allow you to set the car up for on road use and then change the setup to allow for hard on track driving.

Bilstein make the PASM system used on Porsche's and its very good indeed.

Can't really answer 1b mate thats a very personal choice certainly if it was something within your reach and being seriously considered i would encourage you but can't really make the call for ya.

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Ynot

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I've heard only good things about KW coilovers, they are adjustable for street and track driving, you might want to check it out.

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My vehicles are for transportation and fun driving. I have no desire for track driving and any potential abuse to the vehicles other than some on road, spirited driving. Therefore, I'm content with what the factory provides. Call me a prude, but who would knowingly purchase a used vehicle subjected to extreme driving. Not me.

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N4PWJ

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nor me, good point.

however on the topic, i have heard kw variant 3's are a great set up. Tein are also meant to be good, but have also heard some negative reports about them. Tein make adjustable suspension which can be adjusted inside the car i think.
is the black series suspension any different?

Ynot

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Alot of people, you'll be surprised, it's great fun tracking the SLK, give it a try, the next track day is in July, I can't wait.

412driver

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Well said Don. Buy a second SLK for the track and mod the heck outa it, drive tha heck outa it and when you're done, put it in your garage or sell to another enthusiast. The SLK you drive daily and plan to trade or sell to some unsuspecting buyer, well take the hit and disclose the cars past, either way, you pay for the fun...

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Don't get me wrong, I'm sure it's tons of fun. Anyone have an extra SLK I can track? I promise not to run it too hard.

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DansSlk

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I think it all comes down to what you term "extreme" certainly the road itself can put the SLK under extreme stresses driving in bad weather conditions heavy rain, snow and so on will do the car far more harm than a track ever could you also have to take into account other factors that come into play things like potholes in the road sometimes simply can't be avoided some people don't even try to avoid them and the stress that puts on the suspension and axle is huge i can almost guarantee that a pothole strike will have adverse effects on your cars alignment.

Of course the track scene can do harm also but I'm talking things like 1/4 mile runs it does not take many of them to do permanent damage to the transmission system, attempting to power slide the car or cause the wheels to spin up such as in a burnout or 360 are very bad for the cars health but not often the track itself.

If you only drive your car in dry conditions on roads of autobahn quality then on-road driving is going to have less of an impact than track driving, if you drive your car in anything other than perfect conditions poorer quality roads or bad weather then your putting more wear and tear on your car than track driving.

When you think about it the track is a very good place for a car at no point is it under stress sure its going very fast but its built for that, the engine will be operating at higher RPM's but again the cooling system is capable of maintaining acceptable operating conditions, the transmission itself is not bothered its not been put under the huge stress of a 1/4 mile run or 0-60 runs on the road its been accelerated briskly to speed but not ragged silly because on a track there is no need, the suspension is active but since tracks tend to have very good surfaces its more relaxed than it is on an average road.

The brakes get used more and that will shorten the life of the pads and disks but they are wear and tear items anyways designed that way and of course tires will get a pounding but any summer tire will have had hard driving playing a factor in its development and again its wear and tear.

I would buy a car thats spent 5 years only on a track before i would a car thats spent 2 on the road its hell for cars hence the beaters for everyday use and the SLK ain't no beater, the whole track is hard on the car is a myth its the road you wanna watch out for.

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F111F

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Thanks for the input. The PSS9 which is fully adjustable was recommended. I want to look at the cost of upgrading. I am looking at some used 55's because of the price advantage.

I also appreciate the input from the rest of the group. My wife has voiced some of the same concerns that was voiced on this thread. I understand that tracking seems to be hard on the car, but I monitor the temperatures, oil, brakes, etc., very closely. These cars are a dream on the track and handle well and hold up very well. N/A engines also have a HUGE advantage. I saw more temperature swings on my engine while driving through the hill country 4 weeks ago, compared to 90+ degree temps in College Station this past weekend. Dan has a point, on my way to work, hit a huge pothole, and worried about what I did to the alignment. The tracks are some of the best roads I have driven on. Other than brakes and tires, tracking seems to not be that bad on a vehicle. And it is a safe environment, compared to "racing" on a city street. Safe driving is the primary concern when tracking your car.

412driver

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Good points Dan and I agree. The roads of the world are generally poor to acceptable at best. Wear and tear from normal road use may well be worse than the same miles on a smooth track. However, the average person buying a used car expects that the car has been used as intended and one that has been used for other than intended should be so represented when sold. The buyer should have the option to buy or not after considering the particulars of that vehicles life. You and I would buy a tracked car knowing it was properly maintained and cared for in accordance with that use. A person selling a home is required to disclose faults etc of the property and a failure to do so has been upheld in the courts as fraud. The same is true with cars and case law is in place regarding mileage tampering etc. Why risk litigation by not disclosing that a vehicle was driven at top speed on a track for hours. In disclosing this you will reduce your pool of buyers by 90% and thusly your resale recovery by many thousands. I sleep well every night knowing no person has ever been dupped by me intentionally.

cyberdrakon

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412, I don't know how much more wear the track will do to the car, there are no parking curbs, few potholes, few accidents (and when they happen it'll show on the car), no speed bumps, no red lights, not much stop and go traffic....etcetera....Most of the things that wear out on the track will be normal wear items, except they wear at a far accelerated rate.

Also Don, 19's aren't factory are they? F111 is also considering the AMG shocks, which are factory items also....

i would rather buy a used car from someone who admits to occasional track use, than from someone who denies any hard driving at all (how likely is that?).

DansSlk

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Hi Doug mate,
Of course i am certainly not trying to say that you should hide the cars history from anybody and its not something i would consider doing for moral reasons more than anything else.

The point i was trying to get across and you and F111F have both correctly understood it is that the track is not a very stressful place for a car its just a myth thats passed down that a track involving high speeds considerable brake use and all the rest of it is very bad for a car when ultimately its car heaven the road is the worst place for them because of factors outside of the owners control.

For legal reasons i am not allowed to buy cars from my own shop so i go to the closest dealer for purchases and in selling my M3 all i was asked was has it had the 1000 mile service completed they did not even ask to see the log book or inquire about its history now the car has been tracked but was very well cared for and i don't have that nagging feeling some poor bugger has a M3 thats giving them loads of crap i know it will be performing well for them and if the salesman had asked i would of course informed him of the cars on track use but he didn't so he knows nothing of it.

I guess my point with that is (and if we use the house example here) if i was selling one with foundation problems then of course everybody in the sales process would be made aware so that the buyer makes the informed choice to buy the house and attempt to fix it or not bother but if the house had suffered a failed plumbing joint i would not inform anybody of that unless questioned because it has no effect on the home whatsoever, same with a car if i was selling something with a leaking head gasket the buyer would be made aware of that even before they viewed the car but if the same car needed a new brake caliper the buyer would not be told because they don't need to know the problem has been fixed and thats all there is to it, i guess thats how i feel about track use also its not something that will have any negative effects on the car it wont shorten its life or cause it to underperfom so the buyer does not need to know because its irrelevant of course if i was directly asked has this car been driven in any track situation i would tell them the truth.

I think of all the people out there constantly doing 0-60 runs and 1/4 trap times just for the hell of it now buyers of those cars should be made aware of that because its not good for the car but do you think it ever gets mentioned? i would guess a few times outta every million you know. (Must have been writing this at the same time as Edward and he has hit on the same point about hard driving)

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F111F

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My wife is in real estate so I understand your example. If I was selling the car, and it was asked I would tell the truth. However, whether buying a new home or used home, there are many issues that are not disclosed, that if you knew, would be infuriating (sic?), but have little to do with the "value" of the home (i.e. the A/C compressor has SEER 14 but coil only rated for 9, so your A/C is only really a SEER 9!). On the other hand, is the home repainted every year?, does not painting every year decrease the value of the home? Only if you wait too long.

On the other hand, before you can track a car, you have to check it and an ASE Approved Mechanic sign off, because they want your vehicle in top notch condition. Normally, I can run brake pads down, tires to bald, never change brake fluid, etc. Tracking a car, you are constantly servicing your car. I personally put more time and effort into making sure the car has new fluids, etc., and is in top notch, almost show room condition so that I can track my car, than I ever did with either one of my Lexus's (Lexi?). Just some more thoughts to ponder, imho.

I don't want to rant, and I think it is great that most folks don't want to track their SLK's and want to keep them at showroom quality. Believe me I understand. But I have reached an age, where I kept putting off things, and no longer want to fade to black, but want to explore life. I recently went down double black diamonds (with a ski instructor) at an age, when most folks have quit skiing. I thought in my 20's I could never do that, now I am wondering why was I afraid to try? Same with owning the SLK, and worse, now I have the AMG fever. Tracking is something I thought only young guys could do. It is for all ages, for fathers and sons/daughters. It is great to see families enjoying thing and doing things together. I don't get to do that, but I get to enjoy these activities and see others enjoying them also.

I have seriously thought about getting a track only car (it would have to be a Yugo!?!), but the SLK does handle like a dream. MB got it right!

F111F

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Agree and understand.

F111F

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See my link at the beginning of the thread. The SLK AMG 55 owner, thought that it could be ordered through MB (used on E55 AMG?), and could be installed on the SLK. It is an adaptive adjustable suspension to change from normal driving to track driving put on by AMG. I have a sneaky feeling, that it is a Bilstein, since they are suppose to be a German company (PSS 9 system).

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OK, I've been educated on tracking a car and many valid points have been raised. Still, I'm very protective of my vehicles and try not to misuse them. In my life, I've had virtually zero mechanical problems with any vehicle I owned due to proper care and servicing. Tracking is fine but still not for me. I would feel much more comfortable doing the NASCAR or AMG experience events with vehicles provided.

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