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Author Topic:   NEED HELP WITH FORWARD BITE
marksracing
Dirt Forum Racer

Total posts: 79
posted November 06, 2005 10:53 PM  
CAR IS GREAT IN AND THROW THE MIDDILE .BUT HAS NO BITE OFF THE CORNER JUST SPINNING THE TIRES . SET UP IS SPRINGS LF 800 RF 850
LR 175 RR 175
SHOCKS LF MED RF MED
LR BILST 1044
RR BILST 1044
RIDE HGT LF 6 3/4 RF 7 1/2
LR 7 1/2 RR 7 3/4
% LEFT 53% REAR 55% CROSS 48% 70LBS OF LEFT REAR

THIS IS ON A METRIC CAR THAT WEIGHTS 2100 LBS WITH OUT THE DRIVER. ALSO THE % ARE WITHOUT THE DRIVER

johder
Dirt Forum Racer

Total posts: 100
posted November 07, 2005 04:14 AM  
2100 Pound Metric?

CLBaker25
Dirt Maniac

Total posts: 193
posted November 07, 2005 07:21 AM  
I would probably soften your right rear to a 150. With a 2100 pound car you probably can go lighter than a 175. We run a 175 right rear on a 3100 pound car. The lighter right rear spring will loosen the car a little on entry but will tighten you up on exit.

juliaferrell
Dirt Freak

Total posts: 370
posted November 07, 2005 07:23 AM  
Why would the softer RR spring loosen entry? Won't that increase crossweight, tightening entry?

CLBaker25
Dirt Maniac

Total posts: 193
posted November 07, 2005 11:13 AM  
A softer right rear spring can loosen entry because as weight trasnfers to the right rear corner a stiffer spring will push down harder than a softer spring. So as an example if 300 pounds transfers to the right rear spring. If you had a 150 pound spring the spring should compress 2 inches. If you had a 175 pound spring in the right rear the spring would only compress around an inch and 3/4. So it pushes down harder on the right rear with the stiffer spring. The softer spring more of the weight transfer is used to compress the spring instead of press down on the right rear tire.

IMO increasing crossweight will loosen a car on corner entry because you will be taking weight off of the right rear and putting it on the left rear. The only time this is not true is if you keep the car loaded up on the left rear on corner entry by keeping the car very straight then more cross will make the car tighter because it causes the left rear to bite harder.

[This message has been edited by CLBaker25 (edited November 07, 2005).]

dirtyboy58
Dirt Full Roller

Total posts: 40
posted November 07, 2005 06:49 PM  
2100 with motor and trans if so please tell me how

o5racer
Dirt Freak

Total posts: 402
posted November 07, 2005 07:51 PM  
Pics would be nice to.
Nick

marksracing
Dirt Forum Racer

Total posts: 79
posted November 07, 2005 08:08 PM  
IT IS A SIMS LIMITED MOD IT IS NOTHING MORE THAN A METRIC HOBBY STOCK WITH A MODIFIED BODY ON IT. WHAT ABOUT SOFTING THE FROUNT SPINGS WHAT WILL THAT DO FOR GRIP OFF THE CORNER.

CLBaker25
Dirt Maniac

Total posts: 193
posted November 08, 2005 07:22 AM  
You might think about stiffening your left front spring to atleast a 900. I would also go with a 150 right rear for sure.

Lower your front spring rates will cause the car to get on the front end more and will decrease the amount of weight transfer to the rear. Overall this would give you less forward bite.

[This message has been edited by CLBaker25 (edited November 08, 2005).]

nyracer77
Dirt Roller

Total posts: 10
posted November 08, 2005 07:39 AM  
I have found with our car if the car is handling fine but we are having bite problems I always check our pinion angle. we usually use 5 and a half degrees down angle on it, but have been told and have used upto 7 degrees. It helps on the forward bite part.

racer17j
Dirt Forum Champ
Total posts: 5390
posted November 08, 2005 05:30 PM  
RACER17J THE REAR SPRING ARE 15IN HYPERCOILS THE RIGHT REAR HAS SOME UP HILL ANGLE. LEFT REAR IS ALMOST LEVEL

matt9
Dirt Full Roller

Total posts: 34
posted November 08, 2005 07:54 PM  
hey what does this up hill and level angles mean on your rear springs? just wondering. your problem may not be just be set up. we have found that a good cornering car with no bite may be a result of too low of a gear ratio. what tranny and rear gear are you running? you may consider trying a higher gear ratio, it will help on blowing tires loose on exits. we run sport mods and your set up is really close to what we run except the front springs. we run 600 across the front. shocks make a big differeence as well.

racer17j
Dirt Forum Champ
Total posts: 5390
posted November 08, 2005 08:41 PM  
i am not following you. how does longer springs change pinion angle. you raise the spring buckets to compensate for the longer springs.

44nymod
Dirt Maniac

Total posts: 120
posted November 09, 2005 01:54 PM  
I have been talking to alot of Drag racers and circle track guy's and what I've learned about the pinion angle is this!
On a factory type suspension car that really has no movement lifting wise in it you don't want alot of pinion angle.
Pinion angle in a suspension like this causes bind and slowes the drive shaft down making people think that it is creating forwardbite!
What I do in the car's that I drive and set-up is I add the angle of my drive shaft and the angle of my rearend together to get my 7 deg pinion angle.
Example drive shaft 5 degree's plus 2 degreee's rearend angle equals 7 deg pinion.
All the car's I have set-up this year have won and gained rpm's by doing this.
A friend that has a driveshaft shop tried this theory on a driveshaft dyno and it held true!
As far as no forward bite take the RR spring down and bump your LR bite up to 100 lbs. That should drastically help.

racer17j
Dirt Forum Champ
Total posts: 5390
posted November 09, 2005 09:28 PM  
now that more sense racer. thanks for the help.

    

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