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Author Topic:   What are they doing that we 're not?
xhubby
Dirt Freak

Total posts: 376
posted July 19, 2004 08:15 PM  
I,ve gotten some great advice & opinions on here before, so I thought I would try again. We have a consistant top 5th-7th place car (if we don't get crashed), but we seem to be getting passed by cars running in the middle groove on a dry slick track. When we try to run there, the car gets just loose enough that we either get passed on the bottom, or just hold our own. Driver says the car is very drivable, just not fast up there, & that's where we are getting beat.Is this a side bite issue?
Last weeks setup: DW-8 short 2-link 112" wheel base.
Springs-LF 650, RF 750, LR 225, RR 200
Tires- Left side 8psi, RF 14psi, RR 12psi, 3/4" stagger in rear, 1.5" in front
left-52.2%, rear 59.6%, 113 lbs LR bite
Shocks- LF-30/30, RF 20/50, LR 30/30, RR 20/20 (had about 4" of travel on the RR shock, & 3" on RF)
Put 1/2" spacers on LR & LF
shorty bar second hole from bottom on pinion,& 8" up on chassis (didn't have time to check angle)
both trailing arms in top hole(about 13*).
What do they know that we don't?? Any ideas?
Sorry this is so long.

[This message has been edited by xhubby (edited July 19, 2004).]

dirtywrench13
Dirt Freak

Total posts: 324
posted July 19, 2004 08:56 PM  
may want to try some more air pressure depending on the tires you can run.a little more wedge could be the way to go?

2nd2none
Dirt Forum Champ
Total posts: 755
posted July 19, 2004 09:07 PM  
dont be afraid to put more rear % in it either. I know it's already at 59.6 but if the track is that slick 61-62% might be the ticket.

mod70
unregistered Total posts: 755
posted July 19, 2004 09:41 PM           send a private message to 2nd2none   Edit/Delete Message   Reply w/QuoteBBBBBB
I agree with 2nd, a little more rear will help to tighten you up on the low side. Also might want to stiffen up compression on the RR shock when you do it. 4" now will become 5 or more with the added weight and body roll. Sounds like you're really close, just missing one or two small adjustments. Good luck.

joeyi
Dirt Roller

Total posts: 20
posted July 20, 2004 05:18 AM  
try less stagger to run up

2nd2none
Dirt Forum Champ
Total posts: 755
posted July 20, 2004 06:16 AM  
Yeah, I over looked that. Why are you running 1 1/2" of stagger up front? A typical setup uses 1/2" to 1" up front.

de94wcc
Dirt Forum Racer

Total posts: 87
posted July 20, 2004 06:36 AM  
This is very comparable to the set up we ran on past DW 2-links we had. The only thing that pops out is we ran 7" up on the frame for the panhard bar. Maybe you have too much angle? Maybe try to flatten it out a little and you will lower your roll center at the same time. Maybe try dropping your right rear bar a hole also?

dluna
Dirt Freak

Total posts: 334
posted July 20, 2004 08:26 AM  
Wouldn't flattening out the panhard raise the roll center? It will move the location of the roll center more to the right, but raise it at the same time...right?

mod70
unregistered Total posts: 334
posted July 20, 2004 10:05 AM           send a private message to dluna   Edit/Delete Message   Reply w/QuoteBBBBBB
dluna - only if you flaten it by rasing the pinion mount, if you lower the frame mount it will lower the RC and move it left.

i8uracing
Dirt Roller

Total posts: 18
posted July 20, 2004 11:54 AM  

 
I got the following from rpmnet.com

"Example "a" is typical of many dirt cars using a panhard bar mounted to the axle near the pinion gear. if the rear roll center occurs outboard of the panhard's mounts (as shown above), raising the panhard at the chassis will lower the rear roll centers and tighten corner handling! the opposite adjustment gives opposite results. "

I agree with dluna on this one.

nvracer
Dirt Maniac

Total posts: 127
posted July 20, 2004 11:59 AM  
dluna is right. Lowering a short Panhard bar on the chassis will actually raise the RC.

mod70
unregistered Total posts: 127
posted July 20, 2004 03:55 PM           send a private message to nvracer   Edit/Delete Message   Reply w/QuoteBBBBBB
O.K., I'm thinking about the rear moment center then. (dug into my Circle Track mags)

[This message has been edited by mod70 (edited July 20, 2004).]

xhubby
Dirt Freak

Total posts: 376
posted July 20, 2004 04:35 PM  
Ok, two things mentioned here have got me wondering about some things. Fist, we just moved our RR bar up a hole 2 weeks ago to get more rollsteer on a tacky track. Never thought about moving it back down for a dry tack. Duh. Second, we bought a new pinion plate from DW last week. The one we were using was bought from our local racing shop. When we set them together, we found that the four vertical holes on the old one were about 2.5" lower than the new one from DW. We were running the panhard bar in the second hole from the bottom on the old one, then put it in the second hole from the bottom on the new one, thus raising our roll center. The second hole from the bottom on the new plate matched up with the top hole on the old plate.Double Duh. With the angle we were getting with the old plate, the car was standing up like a honeymoon d***. With the new plate, more like a 50th anniverary. Not at all.LOL.

[This message has been edited by xhubby (edited July 20, 2004).]

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