I HAVE THE KW V2 but had some install problems as some know but i love them!

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

Which pro drivers did you pass in fully prepped GT2/GT3/NSX's? Which track?

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.

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.

brabus:

missed you at the Q last weekend. got beat by a mustang with R compounds. Let me know when you get your LSD. I'm still considering it...

Are you looking at the Brabus or the Quaife LSD?

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.

I'm going to disregard all comments as to expertise or experience, and provide the following information that worked well for me:

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.

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)

Quaife!

it's not the same GT that can't drive ?

my p-zero-nero are almost toast ... should be there for the next TART event.

get the darn LSD w/ me!

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???

this install is beyond my experience & available time (unless you know EXACTLY what your doing) ... I was talking to evosports since they have done quite a few quaife's (c55's & e55's) ...

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?

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.

I'm up for an LSD if we can the commitment for a group buy / discount...

I've been laying too much rubber around San Diego considering that I prefer to drive with ESP turned off.

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.

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.

Yes it's that time of year!!!

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.

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.

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.

I would be down for the group but. Did those other #'s translate to installed pricing from Evosport?? Or is 1700 just for the LSD????

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.

ummmm ... ... ... ... sorry ...

Once the LSD goes in I'll have more understeer as well

It's about $2.5K-$3K for a Quaife LSD installed @ Evosports ... I'd like to get that down a little...

I think the crux of the message (not mentioned yet) is that you need to establish an operating pressure for the tires not a cold pressure. On a heavy car like a C32, on the track you will gain several lbs. of pressure as the tires get hot, while on the street you may pick up a pound. I experimented a lot at two different tracks and found that I was reaching a 40lb. hot pressure if I started with the cold pressure at 34 to 36 lbs; and that resulted in the best turn-in. If I had started at 40lbs, I'd probably end up at 43-45lbs at which point you are losing contact patch and reverting to understeer. So 34 lbs becomes 40 at the track but only 35 on the street.

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.