Region: Des Moines Valley
Car #: 59
Year : 1991 Posts: 1910
Status: Offline
posted
I'm with Jason - when you guys figure out just how much difference it makes to put one side rear on full stiff and the other on full soft, and when that would be appropriate, let the rest of us know.
Drago, tell them, you are as good as anyone with different bar settings side to side.
Jim Daniels
Guest
Status: Offline
posted
I always think of it in terms of the unsprung weight a corner has. As if I were pushing down the unloaded corner.. What effect does more or less leverage (firm to soft setting) have on the grip of the other side.
Region: WDCR - 042
Car #: 75
Year : 93 & 95 & 99 Posts: 3727
Status: Offline
posted
Jason, I have no idea about any of the math these guys are using. Here is what my simple brain says. If the soft setting is lets say 50" hole to hole and the medium is 48" and the stiff is 46" the soft/medium would be 49" and medium/stiff would be 47". The butt suspension meter tells me to tighten up the inside link relative to track direction.
-------------------- Mike Collins MEATHEAD Racing http://www.SHEETZ.com The MEATHEAD Racing 2010 Calendar is up!!!! www.MEATHEADRacing.com SMAC Member WDCR-SCCA SM Drivers Rep. ALL OPINIONS ON RULES OR SPECIFICATIONS ARE JUST THAT, MY OPINIONS!
Region: Lone Star
Year : 1990 Posts: 4253
Status: Offline
posted
This was a fun thread, maybe I'll play around with this some more Jason and see what I find out empirically. I learned early on in my career that you can spend a lot of time doing multi-variate differential equations to do an impedance match, and you still have to tweak it.
Oh yeah! Todd, nobody does Diff Eq. when you can use transforms.
Sometimes it's easier just to make an educated guess and tweaking it.
-------------------- "Your victory is tainted! Asterisk! Asterisk!!!"--Lisa Simpson
Region: SouthEast
Car #: 28
Year : 95 Posts: 3756
Status: Offline
posted
Well, it was just 27 in the front and that at the advice of someone speedy. It didn't really work for me but I think the conditions were different.
Don't worry AG, I'll see if I can get you on as test driver. I'll be talking to Jean Todt this week. He's a nice guy, I'm sure we can work something out.
Jason
-------------------- Jason Holland Semi-interested civilian
I'm actually taking a college-credit class in chassis setups with a guy who literally wrote a book on race engineering and I asked him this question a week ago. He said it doesn't matter which side is shorter or longer and that it does give you 1/2 adjustments. But it does not tune each side separately. The whole thing twists as a unit.
Region: Houston
Car #: 91
Year : 1991 Posts: 2171
Status: Offline
posted
quote:Originally posted by Sphinx: I'm actually taking a college-credit class in chassis setups with a guy who literally wrote a book on race engineering and I asked him this question a week ago. He said it doesn't matter which side is shorter or longer and that it does give you 1/2 adjustments. But it does not tune each side separately. The whole thing twists as a unit.
Here's his book in case anyone cares: <a href="http://www.sae.org/news/releases/handsonracecar.htm" target="_blank" style="text-decoration: underline">http://www.sae.org/news/releases/handsonracecar.htm</a>
Unless you have preload...
-------------------- Do I turn my 99 Hard S into a killerfast SM or seek a donor?
quote:Originally posted by Kent Carter: Unless you have preload...
So, if we have preload on one side and no preload on the other, that would have no effect on the forces acting on or generated by the swaybar. The forces at the ends of the swaybar have to sum up to zero.
That you may have engineered preload will have no effect on which holes you select on the sway bar.
I don't understand why you'd ever want preload on the endlinks. It seems to me that there are better ways to fix whatever it is that is supposed to fix.
Region: Houston
Car #: 91
Year : 1991 Posts: 2171
Status: Offline
posted
The endlinks are usually adjustable, with the goal of eliminating preload. I was just adding a bit of precision to your statement that you can't tune one side of the car or the other by the swaybar (not that you were really trying to say that). You can, with preload, but (like you) I doubt you'd want to.
And yes, I agree, that which hole it is in doesn't matter from a preload perspective. We always use all of the holes to get '1/2 hole' adjustments. When others found out, some were shocked and unsure if it was a good idea, as though it would cause the earth to explode.
-------------------- Do I turn my 99 Hard S into a killerfast SM or seek a donor?
Region: Waterford Hills
Car #: 38
Year : 96 Posts: 348
Status: Offline
posted
You can only preload one side. Meaning that one side of the bar the end link will been in compression and one side will be in tension as the car is sitting in its static state. It’s kind of like messing with cross weight to tune in your car.
-------------------- Ralph Provitz #38 2008 WHRRI SM Champion 2008 WHRRI Top 10 Overall V2 Motorsports, Race support, Data Dude
Region: Houston
Car #: 91
Year : 1991 Posts: 2171
Status: Offline
posted
Ralph,
Doing so puts more force (weight) on one wheel and removes the same from the opposite side, all springs being equal. So, in effect you are 'preloading' both sides, just in opposite directions.
-------------------- Do I turn my 99 Hard S into a killerfast SM or seek a donor?
Doing so puts more force (weight) on one wheel and removes the same from the opposite side, all springs being equal. So, in effect you are 'preloading' both sides, just in opposite directions.
I think Kent and Ralph nailed it. Conclusions: 1) You can't preload just one side (despite my earlier hypothetical) 2)this is a crappy way of messing with your cross-weights and 3) the holes effectively give you 1/2 adjustments and are basically side independent.
Region: Waterford Hills
Car #: 38
Year : 96 Posts: 348
Status: Offline
posted
quote:Originally posted by Kent Carter: Ralph,
Doing so puts more force (weight) on one wheel and removes the same from the opposite side, all springs being equal. So, in effect you are 'preloading' both sides, just in opposite directions.
I guess I think of preloading as adding pressure.
So as my pea brain sees it, one side is preloaded and the other side is unloaded.
I think we are on the same page.
-------------------- Ralph Provitz #38 2008 WHRRI SM Champion 2008 WHRRI Top 10 Overall V2 Motorsports, Race support, Data Dude
Region: South-West
Car #: 88 / 188
Year : 1995 Posts: 67
Status: Offline
posted
I'm still not sold on any of this! The only thing that matters is crossweight change. Rrrright? I started digging into the math and got a headache and ended up with a bunch of crumpled paper on the floor.
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