c55 suspension upgrade????
MBWorld Fanatic!
Joined: Jul 2004
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From: Hong Kong
C55AMG W203; 330i E90
hope someone here gives an advice.
My C55 has done 33000km.( the current PS/2 tires done ~20000km) Recently months, I found the ride quality has been so comfortable. Everything about the car seems to be quiet down e.g engine noise. One thing I am puzzled , it is the stock suspension feel , is never as stiff as when the car was new.
I actually like the way it is. But , does that also mean, it is time I need to replace the suspension systems to new ones (still stock) e.g. shocks
thx
My C55 has done 33000km.( the current PS/2 tires done ~20000km) Recently months, I found the ride quality has been so comfortable. Everything about the car seems to be quiet down e.g engine noise. One thing I am puzzled , it is the stock suspension feel , is never as stiff as when the car was new.
I actually like the way it is. But , does that also mean, it is time I need to replace the suspension systems to new ones (still stock) e.g. shocks
thx
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From: Diamond Bar
2005 Renntech C class
Lifting throttle is definitely improper driving technique. Trailbraking is taught but it is crude, dangerous, and really not as fast. Sooner or later with trailbraking you're going to be too hot into a corner think you can trail brake into it and then apply too much braking. The car will straighten out and off you'll go.
Whatever technique works for you... fine; but it will be slower and that's what it's really about right? Before I get flamed, know that I have been through many racing schools front, rear, and mid engine, and have a couple of dedicated race cars etc, so don't get offended. BTW my first race school I was in a professional drivers group and I beat every student and the instructor when I was 17, so maybe I am not the right person to talk to. Further when I had my stock 911 996 at the track I beat fully prepped gt2's gt3's 360's, an andial 993tt, flipped 996tt turbos and an NSX fully done with everything including supercharger driven by a professional drivers. I did go through a full set of pads though!
Anyhoo, I found that while driving the car in the canyons the other day, that the best way to really get the car to not understeer and instead be neutral through a corner is after making sure the car is neutrally loaded, (that is if coming out of the opposite corner to brake to reduce the opposite load and negate the transfer), is to almost set the car at an early apex slightly and throttle steer the car by flooring it, much like driving an all wheel drive car- flooring it before the apex. The turn in sucks, but it is neutral, has equal slip angle as such, and is the fastest your going to get with the current setup. This is of course after making sure to set the fronts pressure lower than stock, esp is off and you're not going to wreck into anyone while trying this! etc.
Whatever technique works for you... fine; but it will be slower and that's what it's really about right? Before I get flamed, know that I have been through many racing schools front, rear, and mid engine, and have a couple of dedicated race cars etc, so don't get offended. BTW my first race school I was in a professional drivers group and I beat every student and the instructor when I was 17, so maybe I am not the right person to talk to. Further when I had my stock 911 996 at the track I beat fully prepped gt2's gt3's 360's, an andial 993tt, flipped 996tt turbos and an NSX fully done with everything including supercharger driven by a professional drivers. I did go through a full set of pads though!
Anyhoo, I found that while driving the car in the canyons the other day, that the best way to really get the car to not understeer and instead be neutral through a corner is after making sure the car is neutrally loaded, (that is if coming out of the opposite corner to brake to reduce the opposite load and negate the transfer), is to almost set the car at an early apex slightly and throttle steer the car by flooring it, much like driving an all wheel drive car- flooring it before the apex. The turn in sucks, but it is neutral, has equal slip angle as such, and is the fastest your going to get with the current setup. This is of course after making sure to set the fronts pressure lower than stock, esp is off and you're not going to wreck into anyone while trying this! etc.
Also, I would highly recommend not running tire pressures below stock because that air in the tire is supporting the weight of that big V8 you got there and I wouldn't want to mess with that.
Member
Joined: Jun 2006
Posts: 137
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From: 858
2005 Brabus C55
spr,
too tired to digest the entire thread now, so...
never drove a stock c55, but I have brabus springs + offset front & rear wheels ... it's not perfect but probably less understeer than stock.
... also...
It's time for an LSD dammit! ... PM me.
too tired to digest the entire thread now, so...
never drove a stock c55, but I have brabus springs + offset front & rear wheels ... it's not perfect but probably less understeer than stock.
... also...
It's time for an LSD dammit! ... PM me.
Super Member
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From: Los Angeles, CA
2006 BMW X5 4.8is and 2005 C55 AMG
Are you looking at the Brabus or the Quaife LSD?
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C32 AMG
Trail braking: Crude, dangerous, and taught by Skip Barber.
http://www.skipbarber.com/videoFiles...ing_School.wmv
While scoping out possible Christmas presents for myself, I found this Skippy video.
About 2/3 through the video, they show the graphic: "Proven curriculum - TRAIL BRAKE ROTATION" Crazy b@stards.
While scoping out possible Christmas presents for myself, I found this Skippy video.
About 2/3 through the video, they show the graphic: "Proven curriculum - TRAIL BRAKE ROTATION" Crazy b@stards.
MBWorld Fanatic!
Joined: Feb 2003
Posts: 1,415
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From: Charlotte, NC
Had: 1987 300TD, Had: 2004 C230 Sport Sedan, Have: 2014 E350 Sport, Have: 2019 S450
Increasing the rear tire pressure allows less contact patch and slip angle = less grip certis paribus. Decreasing the tire pressure increases grip on that corner. Go read any credible suspension/driving book.
As for my experience or technique, I was giving my experience to help others. Your explanation on technique is that of an novice. I will waste my time no further educating you; go to a school and read some driving books instead of merely listening what some "driving instructor" who thinks he knows what he is doing tells you. Comedy.
If anyone could tell me where I can obtain the negative camber bolts and what their part number is I would appreciate it. Thanks Sean
As for my experience or technique, I was giving my experience to help others. Your explanation on technique is that of an novice. I will waste my time no further educating you; go to a school and read some driving books instead of merely listening what some "driving instructor" who thinks he knows what he is doing tells you. Comedy.
If anyone could tell me where I can obtain the negative camber bolts and what their part number is I would appreciate it. Thanks Sean
In general, decreasing the front pressure will increase grip at the front, decreasing understeer - BUT . . . if you are looking for a crisper turn-in, this is not the answer, as the turn in will be more sluggish, although the maximum cornering load will be higher.
If you're streeting, then you may want to stay 'as-is', but if you are looking for crisper turn-in at the track, you can try to go with a little toe-out. I was running between 1/16" and 3/16" when racing my Integra (another nose-heavy pig), and the car dove to the apex quite agressively. With toe-out, you get a slight braking effect from the inside front tire (Ackerman steering) when turning into the corner (as it scrubs), which slows the inside tire, rotating the car down toward the apex.
Of course, the downside to this is that when you combine toe-out with negative camber, you wear the inside of the tire. When racing it wasn't an issue, as it actually helped balance the tire wear (normally the Integra was grinding the outside tread bar off of the tires). If streeting with this setup, you may need to turn the tires on the rims, and swap sides of the car (maintaining the direction of rotation, but swapping inside/outside of the tire) in order to get decent tire life.
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Thread Starter
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I learned it there and at bonderant when I was 17. I and most people that have more experience don't use the technique as when going 9.5/10's and say if you make a mistake and need to use more brake- off you go. (I have never done this but have seen it countless times by people trying to go "fast" instead of being smooth)
Member
Joined: Jun 2006
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From: 858
2005 Brabus C55
spr ... sorry for hijacking the thread...
my p-zero-nero are almost toast ... should be there for the next TART event.
get the darn LSD w/ me!
Thread Starter
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where are you picking it up from and at what price??? I am going to do the swap myself a I have a lift and will take it to the local diff shop that has been around for years. It appears that the only parts needed are new bearings???
Member
Joined: Jun 2006
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From: 858
2005 Brabus C55
if Mr. ****, Mr. Baker and possibly you Sean (or other socal folks), can agree to be interested & 1/4-committed ... I can see what their pricing is for the unit & install. Order of magnitude is $1700 for LSD & $1000+ for labor (1.5 guys for a day). Yeah it's pricey, but ...
Sean, who's your rear-end guy? j/k ... pro-gear?
Thread Starter
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hahah. My father's has a guy he uses in LA. It might be that place. I dunno offhand. I thought the LSD without install was around 1400? Is 1700 include the install? I will ask who he was referring to, and no he's not my rear end guy-hehe.
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C32 AMG
Oh no! The dreaded semi-annual "LSD Group Buy" is back! Isn't there a web site that will manage group buys? They work with the vendor and set up a price and means for customers to really COMMIT to buying (credit card payment taken). When commitments reach a certain level, the deal is processed. This way the buy works smoothly and nobody gets frustrated.
Member
Joined: Jun 2006
Posts: 137
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From: 858
2005 Brabus C55
Pro-Gear is in SD. Please do a little research on you dad's guy. Evopsort ain't cheap, but I don't want a total MBZ novice doing my LSD.
Member
Joined: Jun 2006
Posts: 137
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From: 858
2005 Brabus C55
Oh no! The dreaded semi-annual "LSD Group Buy" is back! Isn't there a web site that will manage group buys? They work with the vendor and set up a price and means for customers to really COMMIT to buying (credit card payment taken). When commitments reach a certain level, the deal is processed. This way the buy works smoothly and nobody gets frustrated.
The <$1500 C55 Quaife deals never happened & were not honored (verbal commitments didn't pan out). I also need someone to install.
If someone in SoCal has any ideas or shops, I'm all ears.
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C32 AMG
IMHO, it's generally not worth it. You might save $200, but then you have to wait for the buy to come together, assuming that it ever does. If/when I'm ready to go for the LSD, I'll may the freight.
Super Member
Joined: Nov 2004
Posts: 570
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From: Los Angeles, CA
2006 BMW X5 4.8is and 2005 C55 AMG
Now you guys bring up the group buy!
Oh well I didn't want to have to wait this long to get the LSD.
If anyone wants to do a group buy on a PSS9 or a brembo kit I'm down with that.
Oh well I didn't want to have to wait this long to get the LSD.
If anyone wants to do a group buy on a PSS9 or a brembo kit I'm down with that.
Member
Joined: Sep 2003
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From: Kansas City
'07 E63; 05 C55 gone; '02 C32 gone;1996 SL320;1978 280CE Gone
Understeer
Back to the issue of understeer and tire pressure. It was "suggested" that I do some reading on the subject. The following are some of the articles that support that on a front engine car, reducing rear tire pressure, or increasing front pressure will reduce understeer (or conversely, tend to induce oversteer):
1. Tire Rack: tirerack.com/tires/tiretech/techpage.jsp?techid=58
2. Roger Krause Racing: rogerkrauseracing.com/overundr.html
3. West Texas Region SCCA: wtrscca.org/tech.html
4. Driver's Ed. Education by Hajny: homestead.com/redlinerennsport/DrEdEd22Understeer.html
5. polybushings.com/pages/handlingtips.html
6. Simulator Racer Documentation: tru7h.org/srdp/index.php?pagename=Problems.Handling
7. Nevada Racing: nevadaracing.com/oversteer.html
8. R&S Racing Inc.: rsracing.com/tech-tire.html
9. Wikipedia, Car Handling: en.wikipedia.org/wiki/Car_handling (see p. 8)
10. Sport Compact Car: sportcompactcarweb.com/tech/0506scc_handling_cornering/oversteer.html. This article states re reducing understeer:
"The first option a tuner has is to increase the tire pressure. The harder a tire is inflated, within reason, the smaller slip angle it develops. In the case of a nose-heavy front-wheel-drive car, if you add several psi to the front tires and take some pressure out of the rear, the front tires will run a smaller slip angle while the rear tires' slip angle will increase. This alone can do quite a bit to reduce understeer."
11. Suspension Fine Tuning - Handling Adjustments: member.rivernet.com.au/btaylor/BMWText/technical/SuspensionFineTuning.html
12. Italkart Chassis Setup Guide: italkart.com/chassis_setup_guide.pdf
If you want to reduce understeer on the track you might read these and many other articles that discuss using tire pressures to help control understeer. However, my experience with the C32 was that it was impossible to balance the car well with the wider rear tires, which is the reason I put the same wheels on all four corners in the C55 when on the track. It takes some experimentation to get pressures that work. I already set out the pressures that I find that work well.
1. Tire Rack: tirerack.com/tires/tiretech/techpage.jsp?techid=58
2. Roger Krause Racing: rogerkrauseracing.com/overundr.html
3. West Texas Region SCCA: wtrscca.org/tech.html
4. Driver's Ed. Education by Hajny: homestead.com/redlinerennsport/DrEdEd22Understeer.html
5. polybushings.com/pages/handlingtips.html
6. Simulator Racer Documentation: tru7h.org/srdp/index.php?pagename=Problems.Handling
7. Nevada Racing: nevadaracing.com/oversteer.html
8. R&S Racing Inc.: rsracing.com/tech-tire.html
9. Wikipedia, Car Handling: en.wikipedia.org/wiki/Car_handling (see p. 8)
10. Sport Compact Car: sportcompactcarweb.com/tech/0506scc_handling_cornering/oversteer.html. This article states re reducing understeer:
"The first option a tuner has is to increase the tire pressure. The harder a tire is inflated, within reason, the smaller slip angle it develops. In the case of a nose-heavy front-wheel-drive car, if you add several psi to the front tires and take some pressure out of the rear, the front tires will run a smaller slip angle while the rear tires' slip angle will increase. This alone can do quite a bit to reduce understeer."
11. Suspension Fine Tuning - Handling Adjustments: member.rivernet.com.au/btaylor/BMWText/technical/SuspensionFineTuning.html
12. Italkart Chassis Setup Guide: italkart.com/chassis_setup_guide.pdf
If you want to reduce understeer on the track you might read these and many other articles that discuss using tire pressures to help control understeer. However, my experience with the C32 was that it was impossible to balance the car well with the wider rear tires, which is the reason I put the same wheels on all four corners in the C55 when on the track. It takes some experimentation to get pressures that work. I already set out the pressures that I find that work well.
Member
Joined: Jun 2006
Posts: 137
Likes: 0
From: 858
2005 Brabus C55
...
Member
Joined: Jun 2006
Posts: 137
Likes: 0
From: 858
2005 Brabus C55
MBWorld Fanatic!
Joined: Nov 2005
Posts: 1,513
Likes: 0
C32 AMG
Back to the issue of understeer and tire pressure. It was "suggested" that I do some reading on the subject. The following are some of the articles that support that on a front engine car, reducing rear tire pressure, or increasing front pressure will reduce understeer (or conversely, tend to induce oversteer):
1. Tire Rack: tirerack.com/tires/tiretech/techpage.jsp?techid=58
2. Roger Krause Racing: rogerkrauseracing.com/overundr.html
3. West Texas Region SCCA: wtrscca.org/tech.html
4. Driver's Ed. Education by Hajny: homestead.com/redlinerennsport/DrEdEd22Understeer.html
5. polybushings.com/pages/handlingtips.html
6. Simulator Racer Documentation: tru7h.org/srdp/index.php?pagename=Problems.Handling
7. Nevada Racing: nevadaracing.com/oversteer.html
8. R&S Racing Inc.: rsracing.com/tech-tire.html
9. Wikipedia, Car Handling: en.wikipedia.org/wiki/Car_handling (see p. 8)
10. Sport Compact Car: sportcompactcarweb.com/tech/0506scc_handling_cornering/oversteer.html. This article states re reducing understeer:
"The first option a tuner has is to increase the tire pressure. The harder a tire is inflated, within reason, the smaller slip angle it develops. In the case of a nose-heavy front-wheel-drive car, if you add several psi to the front tires and take some pressure out of the rear, the front tires will run a smaller slip angle while the rear tires' slip angle will increase. This alone can do quite a bit to reduce understeer."
11. Suspension Fine Tuning - Handling Adjustments: member.rivernet.com.au/btaylor/BMWText/technical/SuspensionFineTuning.html
12. Italkart Chassis Setup Guide: italkart.com/chassis_setup_guide.pdf
If you want to reduce understeer on the track you might read these and many other articles that discuss using tire pressures to help control understeer. However, my experience with the C32 was that it was impossible to balance the car well with the wider rear tires, which is the reason I put the same wheels on all four corners in the C55 when on the track. It takes some experimentation to get pressures that work. I already set out the pressures that I find that work well.
1. Tire Rack: tirerack.com/tires/tiretech/techpage.jsp?techid=58
2. Roger Krause Racing: rogerkrauseracing.com/overundr.html
3. West Texas Region SCCA: wtrscca.org/tech.html
4. Driver's Ed. Education by Hajny: homestead.com/redlinerennsport/DrEdEd22Understeer.html
5. polybushings.com/pages/handlingtips.html
6. Simulator Racer Documentation: tru7h.org/srdp/index.php?pagename=Problems.Handling
7. Nevada Racing: nevadaracing.com/oversteer.html
8. R&S Racing Inc.: rsracing.com/tech-tire.html
9. Wikipedia, Car Handling: en.wikipedia.org/wiki/Car_handling (see p. 8)
10. Sport Compact Car: sportcompactcarweb.com/tech/0506scc_handling_cornering/oversteer.html. This article states re reducing understeer:
"The first option a tuner has is to increase the tire pressure. The harder a tire is inflated, within reason, the smaller slip angle it develops. In the case of a nose-heavy front-wheel-drive car, if you add several psi to the front tires and take some pressure out of the rear, the front tires will run a smaller slip angle while the rear tires' slip angle will increase. This alone can do quite a bit to reduce understeer."
11. Suspension Fine Tuning - Handling Adjustments: member.rivernet.com.au/btaylor/BMWText/technical/SuspensionFineTuning.html
12. Italkart Chassis Setup Guide: italkart.com/chassis_setup_guide.pdf
If you want to reduce understeer on the track you might read these and many other articles that discuss using tire pressures to help control understeer. However, my experience with the C32 was that it was impossible to balance the car well with the wider rear tires, which is the reason I put the same wheels on all four corners in the C55 when on the track. It takes some experimentation to get pressures that work. I already set out the pressures that I find that work well.
And that's where I think we have some common ground here. A few lbs of pressure will reduce sidewall flex/roll and improve response, but a few more will balloon the tire and reduce contact patch. Short answer, for street use, where tires are usually cold-to-warm, a few more lbs of pressure will tighten things up; but on the track where tires are hot-to-melting, adding pressure may end up hurting you.
Last edited by Fifth Ring; Nov 28, 2006 at 09:07 AM.
