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Author Topic:   what are we missing???
dluna
Dirt Full Roller

Total posts: 42
posted June 06, 2002 09:40 PM
It has been a long time since I have posted anything on this site. Our race team has had much success this season thus far, and I accredit 99.9% (gotta leave some credit for the driver) of it directly to this site. BUT...the days are getting hotter and the tracks are getting dryer. We have always had a tough time with dry slick. We won the heat race last saturday by almost half a lap on a tacky track (not due to motor…we just run a cheesey flat top 400), then gradually moved back during the feature as the track got slick. ANY help at all would be much appriciated with our set up.
Dirtworks 2 link car:
Shocks are all Bilstein:
LF: 50/50 RF: 30/50
LR: 30/30 RR: 30/30
Spring rates:
LF: 650 RF: 750
LR: 200 RR: 150
Weight Dist WITHOUT driver: Weight Dist. WITH driver:
LF: 563 RF: 505 LF: 647 RF: 484
LR: 648 RR: 597 LR: 750 RR: 667
w/out: Cross: 49.8% Rear: 53.8% Left: 52.4% w/: Cross: 48.4% Rear: 55.6% Left: 54.8%
These distributions were all taken with 12 gal. of alcohol because we were in a hurry last time we had it on the scales…(sorry).
We run a 14 1/2“ left side trailing arm in the top hole and a 13 3/4“ right side trailing arm in the second to bottom hole.
We run a 25“ rubber pull bar at 18 degrees.
We run a rubber J-Bar in the second hole up from the bottom on the pinion.
The left rear spring is in front of the rear end and the right rear spring is on top of the rear end.
Last Saturday we tried leading the right rear by 3/8” and also took off the J-Bar and hooked up a long panhard bar behind the rear end, running right at parallel with the ground.
We are having thoughts about putting in an older 350 engine we have in the garage to possibly let the car hook up better on the dry. 99% of our problem is from the middle of the corner to about half way down the starightaway (yep, we pretty much spinning for about half of a full lap).
We have not had as much time as we would like to mess around with the car on the scales. I am thinking our main problem is rear weight percentage but ANY INSIGHTS are VERY welcome.

Thanks in advance!….(sorry about the novel)

matt newkirk
Dirt Roller

Total posts: 10
posted June 06, 2002 10:03 PM
DLUNA

TRY 59 TO 60 PERCENT REAR. THAT SHOULD HOOK THE CAR UP COMING OFF THE CORNER. I RUN A 2-LINK DW. PM ME IF I CAN ANSWER ANY SPECIFIC QUESTIONS YOU MAY HAVE.

2nd2none
Dirt Maniac

Total posts: 193
posted June 07, 2002 03:19 AM
quote:
Originally posted by matt newkirk:
DLUNA

TRY 59 TO 60 PERCENT REAR. THAT SHOULD HOOK THE CAR UP COMING OFF THE CORNER. I RUN A 2-LINK DW. PM ME IF I CAN ANSWER ANY SPECIFIC QUESTIONS YOU MAY HAVE.


i agree, i run dw 3 link with over 58% rear

dirtbuster
Dirt Maniac

Total posts: 106
posted June 07, 2002 08:21 AM
ditto. More rear weight.

Have you thought about using the short panhard bar in front of the axle??

dluna
Dirt Full Roller

Total posts: 42
posted June 07, 2002 09:23 AM
Ok, all say more rear weight and I do agree. My question is then when it gets dry and you add more rear %, what do you want your cross and left side weight to be? I have always thought you go up a little on cross when it gets dry (like 51% or so). Another thing is when people say 60% rear, that is without the driver right? Our problem is when the driver gets in, it increases the cross by 1.6% and the rear by 1.6%, so I never know which way to set it up.

dirtbuster, that is actually our next step. we didn't have to much luck last week with just taking the j-bar off and putting the long panhard bar on behind the rear end. Does about 8" on a short bar sound good? What kind of angle would be a good starting point?

Can anyone explain to me how the different styles of panhard bars affect the cars handling: j-bar, panhard behind rear end, and shorty bar hooked to left side of pinion.
Do they just affect how much the body rolls?

Thanks again all

dirtbuster
Dirt Maniac

Total posts: 106
posted June 07, 2002 10:01 AM
We also run a short 2 link DW and are using a 12" panhard bar. That is about the shortest you can go and not make the car so erratic it is undrivable. I beleive dirtworks recommends starting it 8" up on the frame and 2nd hole from bottom on pinion plate. This has worked well it reacts very fast which is good on a dry track but on a rough track it becomes a handful. We are still playing with ours (angle) but this should give you a starting point.

Our numbers are very close to yours except we run 58%+ rear. Yes when ever we add rear weight we keep try to keep our left and cross % the same. How much LR bite do you have. With the short trailing arms 20 # should be enough. DW even reccomends RR bite if the car likes it.

autoshop
Dirt Full Roller

Total posts: 65
posted June 07, 2002 11:12 AM
I don't run a DW but I run 60% rear in my harris with 51.5 cross ,the only thing else we change is the right lower trailer arm we put it in the bottom hole on the frame rail.

2nd2none
Dirt Maniac

Total posts: 193
posted June 07, 2002 12:19 PM
i wouldnt go any shorter than a 12" panhard bar. mount it to the left side of the bracket attached to the frame, if you go with the shorter bar that mounts to the inside of the frame bracket the car just seems too irratic. my bar length is 13" and i got it mounted 2nd hole from bottom on LH side of pinion and about 6" up from bottom of frame mounted to far LH side of bracket.

dirtracr
Dirt Forum Racer

Total posts: 79
posted June 07, 2002 10:16 PM
more wedge, more rear

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