03 grt weight transition

[71sponsor]

Will the 90/10 mounted on top of rear end effect weight transfer and side bite? We have an O3 GRT underslung that this year we can not seem to get to roll onto the right rear. The car is flat on the track and lacks side bite. The other thing I have noticed is that the rf shock is bottoming out as well. We have afco double adjustables on all 4 corners, we have tried different spring rates on the rf but it still bottoms out. Played with the compressions on the shocks. Played with percentages, played with J-bar angles. Everything we have tried does not seem to alieviate our flat race car or bottoming out of rf shock. We didn't seem to have these problems in previous seasons, but this year it is present. We mounted the 90/10 for traction reasons at the recommendation of our shock supplier. In previous seasons we ran without the 90/10.

[rubbinsracin]

what is your rf ride height?

[joedoozer]

Any chance the RF is bottoming out 1 time from a hole or when you enter or exit the track? Or is the little rubber slider thingy sliding down on its own? I had to put some zip ties under mine to help keep them in place.

[rubbinsracin]

Any chance the RF is bottoming out 1 time from a hole or when you enter or exit the track? Or is the little rubber slider thingy sliding down on its own? I had to put some zip ties under mine to help keep them in place.

thats a good point. especially if the car is staying "flat" i mean we have our car get a ton of roll and we never bottom out even on times were we have ran a 325 10" spring with a 3c7r shock.

[71sponsor]

Gentlemen,

This is car is an 03 with the new style front end. GRT recommends 3 5/8 inch which is what we are running. Also we have utilized the zip tie trick and it has actually forced the zip tie under the rubber snubber. The track is also fairly smooth, not perfect but not rough enough to cause heavy shock. Also the shocks are Afco t2's by Envy Suspensions. It just seems to me that we are transfering too much weight on the front and not enough on the rear. Our 90/10 shock is a gas charged shock that supposedly will aid in forward traction with the torque arm. Could this constant load on the 5th coil resist chassis roll on the rear of car?

Thanks gents

[HuckleberryB4]

I would check the rubber slider to make sure it's not just falling like stated above. It's common that they wear out and don't give accurate readings. As for the car not rolling over, check the RR shock and make sure the shaft isn't bent and binding up. Check birdcages for binding as well. If you run a chain for a limiter, make sure that's not wrapped up and binding. And lastly make sure that the 90/10 isn't binding and that it can fully and easily compress and that it's not bottoming when the rearend torques up. If you bent the shaft on it or the 90/10 shock is bottoming out, it'll be like running a solid bar in there and the rearend/liftbar won't be able to torque up and lift the car.

If all you did from last year was add a 90/10 that won't keep it from rolling over on the right rear. It just slows the weight transfer getting into the corner. Something is binding somewhere if there were no major changes made from last year to this year.

[abe_05]

I ran GRT's from '96 to '05 and had same problem. What rr spring are you running? I went to running 150rr spring on slick and 200 max on wet, 175 rr was my base line. I gained forward bite and side bite by going down on rr. This would make car roll even and not just front roll.

[71sponsor]

Thanks guys,

Abe, this is the first year we have run these t2 shocks. We are running a 225 RR and 250 LR. We have never ran that soft on RR with this car before. Answer me this question will you. By softening the RR will that effectively move my roll center to the left toward the heavier left rear spring? I just think I have a roll center verses center of gravity issue going on.

[abe_05]

Yea and no. Only way to move roll center is move mounting points, move rear end over, changing j-bar etc. Going softer will make it roll easier than rolling on right front and staying there. Dropping j-bar down on chassis and rear end will move roll center quicker than anything and this will help car roll over also. What pinion mount for j-bar are you running? 4-hole or slider type?

[71sponsor]

Abe

The pinion mount is a notched slider, we are running in the 1st notch up from bottom, we have also ran it 2 notches from bottom. The frame mount is a 8 3/4 from bottom of frame to bottom of slider bracket. The j-bar is mounted in the 4th notch up from bottom. We have also ran it in the 3rd notch from bottom. Are we maybe too high on the frame mount location?

Thanks

[abe_05]

That sounds high on frame. I don't know if I have notes from '05 or not. I will look and see tonight. I am thinking I was around 5-7 in from bottom on frame and bottom slot on pinion to only 1 slot up if track was real wet. Try moving j-bar at pinion all the way down to bottom and drop it on the frame down, try softer rr spring. She going to roll then for sure or something bad wrong.

[poppy]

Abe, I also run a soft spring setup, what are you doing with the LR when you are at 175/150 on the RR?

[abe_05]

I normally ran 500lr. The whole deal with going softer on rr was to make the car roll on the rear not just the front to have a balanced setup. With soft rf spring you run into corner and all weight rolls to right front, all you trying to do is unload lr to tighting chassis up on entry. If chassis rolls onto right side more evenly it will do the same and increase side bite. Everbody drives different and needs different setup for them but car needs to be balanced in terms of rolling front and rear end. This is just what worked for me.

[poppy]

Abe 500 LR that seems like a big split, I run 175 LR and 200 RR. are you runing a swing arm? I have never heard of that stiff a LR spring. Just curious if that is correct or a mistype.

[abe_05]

Sorry, I did. 500 LF 300-275LR