Crate to Super

[Rooster7]

I have been running my 400hp crate motor this year with the Super Lates at Screven Motor Speedway. 1995 GRT. We are currently building a Ford Motor for next year. What changes am I gonna have to make to my car with 300 more HP? My problem this year was I was always too tight...... At first it was getting in.. Started dropping the left front spring rate until it would turn in. Then it was too tight under throttle in the middle. If I did anything to free it up so the motor wouldn't bind up, I would just spin all the way off an be too loose in the center and off.
Current Set-up
LF 400 75shock RF 400 762shock
LR 275 953shock RR 175 94shock
53.6% left
54.9% rear
185lbs bite
lru 23 degrees up rru 18 degrees up
lrl 6 degrees up rrl 2 degrees up
3/8 rr trailing
j bar bottom hole on pinion 7.5 inches of split.
I would let off and roll in and start to turn, nail the brake to set the car and stand back on the gas. I would bind the motor up beyond all belief, and if I did anything to free it up some The car would get so loose it would barely set and spin the tires all the way through the middle and off.

[Rocket Bonehead]

I have been running my 400hp crate motor this year with the Super Lates at Screven Motor Speedway. 1995 GRT. We are currently building a Ford Motor for next year. What changes am I gonna have to make to my car with 300 more HP? My problem this year was I was always too tight...... At first it was getting in.. Started dropping the left front spring rate until it would turn in. Then it was too tight under throttle in the middle. If I did anything to free it up so the motor wouldn't bind up, I would just spin all the way off an be too loose in the center and off.
Current Set-up
LF 400 75shock RF 400 762shock
LR 275 953shock RR 175 94shock
53.6% left
54.9% rear
185lbs bite
lru 23 degrees up rru 18 degrees up
lrl 6 degrees up rrl 2 degrees up
3/8 rr trailing
j bar bottom hole on pinion 7.5 inches of split.
I would let off and roll in and start to turn, nail the brake to set the car and stand back on the gas. I would bind the motor up beyond all belief, and if I did anything to free it up some The car would get so loose it would barely set and spin the tires all the way through the middle and off.


First off, if you have to "nail the brake to set the car", then something is inherently wrong with your setup. You are TOO TIGHT, and you obviously know that, but you still haven't freed it up enough. In fact, I'd say you're too tight all the way thru the corner.


Your RF spring is too soft for the engine weight you have up front. Your LF is too soft as well. For the crate engine, I'd suggest going with a 600LF and a 500RF for starters, and then check your RF travel to see whether or not you are getting in to coil bind. Go as stiff as needed on the RF to keep from getting into coil bind.


Your exit problem is directly related to both your entry and middle issues. Assuming you weigh 2400 (which is common for the 604), your R side springs are too soft. Along with stiffening the RF, I would stiffen the RR to a 225 for starters. I would also add some LRB rod angle or RRT rod angle to help free the car up from the center out. Indexing the RRT rod will be more effective in doing that, but if that isn't an option, go ahead and raise it on the frame. Raising the RRB rod will also free the car up on entry thru to the center. If you're still tight on the gas, you may try softening the LR spring to help the car get thru the center better while on the gas.


As for your shocks, I am assuming you listed them as C/R, so the 2 rebound on the RF isn't helping things any. That will add to your tight throttle condition.


Make those changes and you should be a lot happier with the car in it's current configuration. IF the track is heavy, and the car is tight, you may want to look at raising the J-Bar on the Pinion 1/2" to 1" to keep from pinning the car on the RR.



As for going to SLM, what changes to make will depend on what your engine combination will be. Are you going to run an all-aluminum piece or a alum/steel piece? Your main changes will be with the front springs. I would run the rest of your setup the same (with the changes I listed above) and see how the car reacts before making wholesale changes.



The biggest thing you need to remember and focus on is that these cars (regardless of chassis brand) are built to turn L at the end of the straight. If you have to stab the brakes to get the car to turn, what does that tell you? Realistically, you shouldn't need to use a lot of brake to turn the car. You definitely shouldn't need to stab it or stomp on it (especially in the slick). Regardless of the engine type and HP, if the car doesn't want to turn at the end of the straight, you need to free it up. Front spring rates are CRUCIAL to corner entry. Just about every chassis builder's "baseline" setup will be based on having an all-aluminum engine, so if you have a steel block or all-steel piece, you will need to be stiffer than their recommendations.




RB

[Rooster7]

Thanks RB, I kept telling my "CREW CHIEF" That the front of the car felt to soft and sluggish. We only had 2.5 - 3 inches of travel on the RF. We actually put a 375 on it one night and the car got worse. But at the same time He changed the RR shock and moved the J bar. The car was a handful.
We have 2 motors we are working on. 1 is all steel and the other has aluminum heads. We now have a few months off other than possibly Lowes with the crate motor on Nov 3rd. I ran this year with my crate motor in the Super class. I was a good field filler at best. Made a few big races. Stayed out of the way and had fun. But I am ready for more motor so I can be competitive. I forgot to say my car is 2300lbs. I cannot get it any lighter. 22 gallon fuel cell full with driver.