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This topic was originally posted in this forum: Modified Tech Talk
Author Topic:   Dry Slick Adjustments
GrnHornRacing
Member
posted April 11, 2004 01:38 PM     Click Here to See the Profile for GrnHornRacing   Click Here to Email GrnHornRacing     
This is my first year running a modified full time, so far this year the track has been a tacky track, and the car has been a rocket finishing in the top 5 both times out.

But i know it is approaching the time of the year where we will start getting some dry slick tracks, and want to be competative on these tracks as well.

Okay now for the car. So far the car has been real neautral so far.

The car is a 2003 GRT Modified swingarm car on the left and right side. J bar, long spring pull arm. Spring on the left side is mounted infront of the rearend on the eliminator, and the right side spring is mounted on top of the rearend.

1. Just curious as to what adjustments might need to be made?

2. We are running on alky right now and as we burn of the fuel load will the car get looser or tighter?

3. If you put more angle in the J bar will that give more side bite or increase the sidebite?

4. Also on a tacky track, right now i have the same type shocks on both sides of the rear end, if i was to put a softer shock on the right side what should i expect?

thanks for all the help in advance?


JMillerJr76
Member
posted April 11, 2004 10:39 PM     Click Here to See the Profile for JMillerJr76   Click Here to Email JMillerJr76     
What we will do is when it dries out, we will close the rear stagger up running as little as a half inch or so. Also, we will raise the j-bar up on the frame. That will give you more sidebite. Also you may play around with the tire pressures too, we will drop as low at 7 on the LR, and 10 on the RR. That should give you an idea, and a good place to start.


James Miller
Sooner Motorsports
Norman, OK
405-360-0596

[This message has been edited by JMillerJr76 (edited April 11, 2004).]

GrnHornRacing
Member
posted April 12, 2004 09:21 PM     Click Here to See the Profile for GrnHornRacing   Click Here to Email GrnHornRacing     
Come on guys need a little help here????


Majic Maker
Member
posted April 13, 2004 07:19 AM     Click Here to See the Profile for Majic Maker   Click Here to Email Majic Maker     
Lower your j/bar to the bottom hole on the pinion and decrease your tire pressure two pounds all the way around from what you normally run.



NJantz
Member
posted April 13, 2004 07:29 AM     Click Here to See the Profile for NJantz     

1. Just curious as to what adjustments might need to be made?
There are several things you can do to tighten your car up when the track slicks off but it depends where in the corner the car is loose at. It will be best to wait for when the track starts drying out and make the necessary changes then.

Some typical changes you could make will be to run less stagger, add more rear percentage, lead right rear. You'll also probably add more wheel offset to the LR and decrease RR wheel offset.
2. We are running on alky right now and as we burn of the fuel load will the car get looser or tighter?
-Looser because your rear percentage will be decreasing therefore taking pressure off of the rear tires that in turn reduces the tires frictional forces.
3. If you put more angle in the J bar will that give more side bite or increase the sidebite?
More angle lets the tires accept more load therefore increasing traction in the rear tires. Don't go too far tho.

4. Also on a tacky track, right now i have the same type shocks on both sides of the rear end, if i was to put a softer shock on the right side what should i expect?
A softer RR shock will allow weight to transfer to the RR corner of the car faster when you are picking up the throttle. A softer RR shock will tighten up the car.
Also when you encounter ruts your car will become more erratic.

When the track slicks off you can put softer extension shocks on the front so weight transfers to the rear sooner improving forward bite.



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