The Coffee Clutch

[fndrbndr]

Sounds like you want Fit's place for a GOOD cup of coffee...

[DirtDriver]

well, I was really wanting to ask Jay about something Ske said the other day about camber and the rear axle model on the Muscle cars...but I was also hoping for some Joe...besides, I ain't dressed up enough to visit ole Fit's place o' business.

DD

[fndrbndr]

Man, I don't OWN the clothes necessary to visit Fit's employer.  His customers' trophy  wives would look down their new noses at my Chrysler no matter how much I dressed it up...lol

Edit:  I'm curious about that too, though.  I'm still figuring out a lot of the suspension stuff in the game.  It's opening up a lot for me, but it's definitely still in the "fool around" stage.

Edit of edit:  I'm wondering whether differential settings might be important in light of the changes in camber

[DirtDriver]

Jay should pop in here any minute...you didn't bring any donuts, did you?

DD

[JG4tr]

Good morning everyone.

First order of business: Apologies.

To anyone who may have looked through all of the class threads that I set up yesterday afternoon, Sorry I caused you to waste your time. I've updated the titles of those threads now to hopefully save others from the same exercise in futility.  

Tonight, after I put my daughter to bed, I think I'll get started on a car for the Feb Muscle D challenge. Its great seeing all of the activity and enthusiasm that this latest challenge has stirred up around here and despite the fact that I feel the pull of my next personal project ie: completing the TimeTrials, I think that its time that I get involved.

I tend to be a bit of the hermit type and while the easy thing for me to do is just work on my own projects, I made a conscious decision to open this garage in order to increase my participation and contribution levels within the community that has helped me so much.

I'm thinking that my old sentimental favorite, the blue oval may be the first to get some love. My first job working on cars was at a Ford dealership...

Hey! where'd you all come from! Here I was thinkin I was just talkin to myself.... guess I'm gonna need a second cup and wake up a bit more.

[DirtDriver]

Alright, Jay...get some coffee and listen up. Here's the thing. Ske is kicking out butts...now I know Muscle, Inc. challenges aren't competitions to see who's best and all that...But, I just gotta figure out what he knows that I don't.

Now, the other day he was wondering out loud if the live axle of a muscle car would mean you could run less camber on the rear than other cars. And, of course the payoff would be better straigh line acceleration.

But I was thinking that race upgrades probably eliminated that outdated system with something more contemporary. And I want to know what you think.

Gosh, I hope Ske doesn't wander in here and hear this....LOL

DD

[fndrbndr]

Well, the question isn't "contemporary."  It's "good."  That said, maybe I should flesh out my thoughts a bit.  If you're running very little camber, what about cornering?  Do you power slide, the way we've been driving these cars anyway, and just leave the differential alone, or do you open it up entirely and let the wheels do what they will?  Also, wouldn't larger rims help prevent sidewall flex in this sort of tune, making them more necessary?  I've been playing with this on my ghetto Z.

[JG4tr]

Hmmm... Well, I think that we all know that Ske is pretty quick no matter what he's drivin so, I wouldn't necessarily chalk that up to his cars rearend.

I have noticed that there are cars that, even after you upgrade them to a race suspension, their default rear camber is 0.0 instead of -0.5 like all other independent rear suspension cars. This may in fact be an indication of exactly what Ske was talking about but, I don't know for sure whether or not that's because the rear axle type has not been changed from its original design.

Personally, I have not done any experimentation specifically related to that possibility up to this point but, do generally make an effort, on any type of car, to focus, on the end of the car that is most critical to overall performance, on maintaining the best possible contact patch.

For me, that typically means using camber and ARBs sparingly on that end of the car.  So, for a muscle car I would tend to limit the rear camber anyway.

Has anyone checked their telemetry to see if the rear end is losing too much traction?

[DirtDriver]

Yeah, I always start with the stock tune and I tested the Boss in telemetry for the current challenge. I gotta tell ya I did't see anything that made me think the back end needed more negative camber. But, I tested it at -.8 and it did improve my stickiness through the turns.

DD

[fndrbndr]

Hm.  I might have to try that.  That's my one gripe with the boss, tends to slide out a bit of I'm not careful.  If camber fixes that, I might beat my Z28.

[DirtDriver]

Remember that I was running a pretty low FD...2.90 but having said that I found the only real trouble I had with the back end was when I stiffened suspension parts too much or had ride height lowered too much.

DD

[JG4tr]

the way we've been driving these cars anyway, and just leave the differential alone, or do you open it up entirely and let the wheels do what they will?

 Also, wouldn't larger rims help prevent sidewall flex in this sort of tune, making them more necessary?  I've been playing with this on my ghetto Z.

On the differentials, I typically have mine fairly open on the accel side ( 0-30 for most cars ) My preference is to set it up so that when I hit the throttle hard, the car actually takes a tighter turning radius. It feels as though the rear end wants to twist around an axis centered in the front of the car. This allows me to accelerate, rather than brake when it looks like I'm going to run out of room on corner exit. More time in the gas means faster laptimes.

I actually like having some sidewall flex. In addition to lowering the unsprung weight with the smaller diameter rims, the additional flexing and the increase in grip angles possible mean that the transition from maximum grip to a grip overload and sliding the tire across the pavement, seems less abrupt and even a little easier/ quicker to recover from.

I usually keep my tires aspect ratios in the ranges of 40-30 for the highest performance vehicles and 50-40 for more production level classes, generally speaking. If I know that I'm going to create a targeted build for a specific type of track, I would lean toward higher profile for the tight and twisties and lower profiles for Nissan...

[JG4tr]

Remember that I was running a pretty low FD...2.90 but having said that I found the only real trouble I had with the back end was when I stiffened suspension parts too much or had ride height lowered too much.

DD

I definitely run a soft rear spring in a muscle car. It may boil down to driving style so, I'm not gonna say that everyone should, but for me , it works.

I think that it works because of the weight transfer. If you're running a typical medium to firm spring, the weight transfers to the tire pretty quickly, making it easy to go past the edge of maximum grip. A softer spring should allow the weight to transfer more gradually, reducing the grip demand 'peaks' and making it less likely that the tire will suffer a momentary grip overload and break traction.

[JG4tr]

Mornin folks. Looks like it might be a busy morning for me IRL but, I'll have something to post up on the D class challenge when things have settled down a bit. 

J

[DirtDriver]

Mornin', J.

Kinda busy here, too...need to do the work I been putting off for two days due to the Superbowl of hangovers!

DD