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Author Topic:   Please Help!!!
start79
Member
posted March 13, 2001 08:11 PM
Let me start off by saying I am newbie to modified racing. I have a 98 Harris and raced it just a few times last year. Last year the car had no forward bite at all. So I changed it from a swingarm set-up with an afco torque link & panhard bar and went to trailing arms, with a spring bar & J-Bar. Saturday night at HRP, the car felt ok going in but as soon as I picked up the throttle it was WICKED loose, from the middle out all the way down the straitaways. Managed to do 2 batman turns, which is not good! The car was so loose I was fighting the wheel all the way down the straitaway. Here's what I have:

1" stagger across front.
2.5" stagger across the rear.
3" offsets all corners.
3/8 - 1/2" lead in the rear end.
54% rear wt.
51.5% left side wt.
51% cross wt.
j-bar is mounted almost parallel to the floor (from heim to heim I belive it's 10 degrees.
200# rear springs (mounted in front of rear end).
650# left front, 750# right front.
Trailing arms are in the middle holes.

Track is Houston Raceway Park, 3/8 mi. Tight corners, long straits.

Any help would be greatly appreciated.

Thanks,

Ronny Taylor


dirt racer
Member
posted March 13, 2001 08:33 PM
I agree with the idea that you need more rear percentage, but I'd also add more cross and left. You could accomplish the last two with just a 4" wheel on the left rear. To get more rear, you'll have to add ballast. 50-75 lbs should do it to get to 58%, depending on how far behind the rear wheels it's mounted.
Something else to consider...if you're running tight turns, maybe 2 1/2" stagger isnt enough. It's possible that the looseness you're feeling is coming from the fact that you HAVE to spin your tires to keep it from pushing through the middle of the turn. Once the tires get spinning, any amount of stagger is too much once you get to the straight.

just some thoughts,
Matt


A2KY2K88
Member
posted March 13, 2001 11:02 PM
REDUCE THE AMOUNT OF RR LEAD. THIS IS CAUSING YOU TO HAVE TO SPIN YOUR REAR TIRES TO GET THE CAR TO TURN. REDUCE YOUR STAGGER TO ABOUT AN INCH IN THE REAR. YOU NEED 5% MORE REAR WEIGHT. YOU DO ALL OF THESE AND YOU WILL FEEL A NEW CAR.


CUSTOMPERFORMANCE
Member
posted March 14, 2001 12:58 AM
take out some stagger in the rear. increase your rear % closer to 58%. try a 2 inch wheel on rf and a 4 inch on rr. run no more than 1/4-3/8 lead on rr. try the rr spring behind the housing, left trailing arm in the top hole and the right in the bottom hole. try this and get back to me.


ufb
Member
posted March 14, 2001 09:20 AM
IF THE CAR IS STIIL LOSE AFTER THE CHANGES THEN TRY BUTTING THE 750 SPRING IN THE LEFT AND THE 650 IN THE RIGHT.IT WILL HELP COMING OFF! ALSO ARE YOU SMOOTH ON THE GAS ?TRY RUNNING 4" OF TRAVEL ON THE GAS PEDAL.AND 1TO 1 SET UP ON THE LINKAGE OF THE CARB.HOPE THIS HELPS!


wfoondirt
Member
posted March 15, 2001 05:50 PM
You might want to contact harris, Kelly is really good about helping people with harris cars. Harris has a really detailed base setup sheet that will help you get on track. Most of the above replies are right on track for your car. The only other thing i'd suggest to start is to move the rr spring behind the rear-end and put a 225-250 srping in the left rear. That along with the increase in rear percentage and putting the rr trailing arm in the bottom hole and the lr trailing arm in the top hole should get you pretty close. Also what spring are you running in the torque link. Should be around 7-800# or some guys like to run a progressive. Also that seems like way too much stagger, most harris's that i have seen run no more than 1/2" and even reverse stagger.


36k
Member
posted March 15, 2001 06:01 PM
I appreciate everyone's input. I was up in Iowa picking with my buddy picking up his new Harris a couple of months ago and they were extremely helpful. This go round I'm going to change the stagger, move the trailing arms, increase the rear %, reduce the amount lead in the rear and try a heavier spring. So much for trying one thing at a time.

By the way his 2000 and my 98 are set up the exact same way and have the exact same problem.

Thanks for all the help and I'll keep ya'll posted.

Wauge28
Member
posted March 16, 2001 03:09 PM
You might think this sounds crazy, but if after trying those thing it is still loose, try reducing your cross. I know, sounds crazy but if you take your cross doen a bit and put about 40 lbs of LR bite and take out you leed, I think you will see you were fighting two problems that both resulted in a tight car. By adding weight to the rear, your cross is going to come down a bit anyway and keep your stagger at 1.5 to 2 if possible. Also, are you measuring the rear steer with the chassis of againts the front ball joints? A 96 could be tweeked and could explain a loose feel. Who know, I could be all wet but you might consider it.


start79
Member
posted March 18, 2001 09:19 PM
Thanks for everyone's help. I changed the LR spring to a 225, increased rear % to 57.5, moved the LR trailing arm to the top hole, went to 1/2" stagger, put 2" offset on RF.

During hot laps the car pushed like a dump truck. Found that the RF shock was bottoming out, replaced it and went to the heat race. Car started out feeling pretty good, however was loose down the straights & got progressively worse.

In the "B" the car was extremely erratic to say the least. Problem was discovered Sunday morning after unloading the car and finding that both bolts for the idler arm were no longer there..... So I'll try again next week and let ya'll know if the changes fixed it.

Thanks,

Ronny Taylor



wfoondirt
Member
posted March 19, 2001 09:54 AM
Was the idler loose in the heat also? Alot of racers will disagree and dont pay much attention to it but if the front end is not right it can make the car feel loose. Sounds like your much closer so i wouldn't reccomend any major changes, at this point you should be able to get there with a few smaller changes.


start79
Member
posted March 19, 2001 06:50 PM
I belive the idler arm came off during the heat race. I'm normally pretty good at preventive maintenance, it appears that I dropped the ball this time though.

I'll know more this weekend and keep you updated.

start79
Member
posted March 25, 2001 02:29 AM
Car now has big time push going in. However, the car is not loose anywhere on the track. What do ya'll suggest for the pushing problem?

Also, my car dosen't roll over as much as the other cars, could this be a problem?

36k
Member
posted March 25, 2001 08:53 PM
how much front stagger are you running, what brake bias are you using.


start79
Member
posted March 26, 2001 05:50 PM
I have the following:

STAGGER

LF - 86 1/2 RF 86 3/4

LR - 86 RR 86 1/2

WEIGHT-----

LF 509 RF 531

LR 709 RR 617

56% REAR
92 LBS. LEFT REAR

I started out with about 50/50 on the brake bias, then I started dialing in more rear. Didn't seem to help.

If ya'll need more info, let me know.

I appreciate all the help.



wfoondirt
Member
posted March 26, 2001 06:25 PM
a few thoughts on loosening entry, more diagonal will loosen entry IF the car is significantly slowed by the rear, either by the brakes or the engine, on entry. you might want to try a slightly stiffer lf or softer rf, 100 lbs front spring split is a little much for most tracks. since you said you had a problem bottoming out try rf 700 lf 750 rf. another consideration would be the angle of the panhard bar, i have seen several harris cars have entry problems with the panhard bar at more than 10 degrees, ideally it should be flat to 5 degrees. I assume your figguring your brake bias via guages so as long as your using more rear brake than front your stagger looks good.
what are your shock valving all around? If the push is severe you probably can't fix it with just a shock but if the car is close that may also be a consideration.


start79
Member
posted March 26, 2001 06:49 PM
Shocks:

lf - 75 rf - 76
lr - 93 rr - 93

When I installed my J-Bar I determined the degree by placing a straight edge from heim to heim and then using a degree gauge set it at 10 degrees. The long portion of the bar is almost parallel to the floor. Is this the correct way?

MOD RACER#93
Member
posted March 26, 2001 07:18 PM
The push was when I was off the throttle. It's perfect when I get it pointed in the right direction, no looseness at all. Am I setting the J-Bar correctly?

Thanks,

[This message has been edited by start79 (edited March 27, 2001).]

wfoondirt
Member
posted March 27, 2001 08:22 PM
the angle should be measured between the mounting points. Sounds as if you are doing it corectly. If so 10 degrees is a little much.


A2KY2K88
Member
posted March 27, 2001 10:46 PM
HOW MUCH RR LEAD DO YOU PUT IN?? MIGHT TRY EXTENDING THE RIGHT SIDE 1/8 INCH AT A TIME.


the fact man
Member
posted March 29, 2001 03:56 AM
i think i would double check the front end settings. if you dont get the angle of the tie rods correct with that much movement in the right front it can cause a toe in problem as you enter.

------------------

dan patterson


start79
Member
posted March 29, 2001 09:31 PM
Right I have no lead in the rear at all. The shock that bottomed out was the wrong shock,it was a 9" instead of a 7".


start79
Member
posted April 08, 2001 07:21 PM
Ahhh the saga continues....When I left off the car had a bad push, but handled great otherwise...So I used the shotgun approach this week. I put a 150 lb. spring in the RR, put a 650 in the rf & a 550 in the left front, raised and increased the angle on the J-Bar a bunch. Now I'm loose off. I think I'll lower my J-bar back to where it was at keep at it.. (I know I should have taken some of the angle out of the J-Bar, but my buddy said his car was doing the same thing and when he raised his j-bar it helped) It didn't help me, if thats the cause for it being loose off.

Just keeping everyone updated. All comments are welcomed, good or bad.

Thanks

dirttrackracer
Member
posted April 09, 2001 05:46 PM
When making changes to the panhard bar,make small changes to get the desired effect.You probably could have left the car alone from when it was pushing,and made half the change to the panhard bar that you did.Many times the hardest thing for a new racer to learn is,do not try to make it harder than it is,get close and then fine tune from there,do not try to reinvent the wheel every time you go to the track.And dont worry about your buddy,that could be different driving styles.Keep us posted about your progress.


start79
Member
posted April 09, 2001 09:49 PM
I'll do it and I appreciate the input.


start79
Member
posted April 15, 2001 10:13 AM
Well, I lowered the J-Bar, and it felt like a new car this weekend. Had just a little push going in and was a little loose coming off. But it was a tremondous improvement. Thanks for everyones help.


wfoondirt
Member
posted April 15, 2001 10:41 PM
The 150# rr spring may be part of you entry/exit problems. you might try a 175# rr and even a 600 lf if you can't get it the way you like it with j-bar adjustments.


ronwil19
Member
posted April 20, 2001 01:01 PM
Many of these suggestions are good. But heed this one the most. ONE CHANGE AT A TIME!!!! Your changing so much so fast that you really don't know what made the car react the way it is now. Yes, you had to baseline your car, but now, 1 CHANGE AT A TIME. My 3 cents worth.