Sudden lack of forward drive

[missile07]

Ok we have really only ran outside of the top 5 once and that was a drivers mistake but this weekend we noticed a huge lack of initial drive up off the corner. The track was not very slick, the car turned in great on the throttle and driver says is handling better than ever. Says the car stays under him coming off but just lack of drive. Car is with a 604 legal crate on D-21 tires. We ran 2nd and could get under the leader but the car seemed to slower coming off the corner than normal. Small tight corner track.

Heres what we have:

Springs
RF 325 (we lowered this from a 350 this weekend)
LF 450
RR 250
LR 225

5th coil 34 inches out and 275 spring (moved this one hole forward this weekend)

Scaling with no driver
Left side 53%
Rear 52.5%
Cross 49.5-50%
20-30 bite

Right side bars are lengthened 1/2 inch past even.

We are leaning towards moving the 5th coil back and going a tick heavier on that spring. Other than the RF spring change and 5th moved nothing else has changed. Car is normally a little tight in but a rocket off.

Any thoughts?

[Matt49]

Softening the RF spring is what killed your drive off the corner. You decreased dynamic wedge. If you're insistent upon running the softer spring on the RF I would recommend less rebound in that shock.
Moving the 5th coil forward probably also hurt initial drive. With low HP applications, my opinion is that further back is better also. But this has a lot to do with how the car is driven, track surface, tires, etc.

[missile07]

Matt 49....thanks for the reply

We went to the lower spring to help in the center of the turn to reduce a slight throttle push. It really helped the car turning in on the throttle and thru the center. Without affecting much what can we do to increase our dynamic wedge. Or would it be better to go back up in spring rate and make a change somewhere else to help it turn.

[MBR Performance]

You could just add static wedge to compensate for the RF spring change.

[missile07]

Thanks for the reply MBR.....we are definitely going to add more wedge this weekend. Just don't want to get out of hand and create a push

[MBR Performance]

Get the bite to about 50lb with the 325 RF

[Dirt_Buster]

Mess with the low speed on the shock. You'll like

[CCHIEF]

Lower your right upper rod @ the frame. Get a bump stop fitted to the RF as you get into the softer RF springs. If your car is barred up, topped up thru out the corner (as it should be with a crate car), adding static wedge wont add noticeable drive. If you then find the car turns very well and has good forward drive but a little slow overall, roll the rr back 2 turns @ a time, the lap times will usually pick up. IMHO Crate cars need max mid corner speed ....compared to a super late. Momentum and neutral thru mid corner is the key to crate cars being fast. Some older cars do not respond well to the softer range RF springs. Is your lr spring lightly loaded a full droop? If not softening that spring till it is will add drive to the car. My opinion from my experience and not intended to discredit or add to any advice given by others.

[missile07]

CCHIEF....left rear comes unloaded at full drop with a 14 inch spring.

I appreciate all the advise from everyone. Like I said the car is good but just wanting to tweak a little at a time to improve.