Smackdown help!

[TEAM56RACER]

I know this thread has probably been started on here a dozen times, but here goes. I have an '05 smackdown with a S7 front end and the following setup. SPRING RATES--LF 500, RF 500, LR 250, RR 200 FRAME HEIGHTS-- LF 3.5, RF 3.5, LR 8.25 RR 8 1/8" SHOCKS---LF 5/5, RF 3/12 (35 PSI) LRF 6/0 (150 PSI) LRB 6/2 (175 PSI) RR 4/4 J-BAR-- 8.5 on frame and 1" below center of pinion BAR LENGTHS--LRU 17.5, LRL 15.5, RRU 17.5, RRL 15.5 BAR LOCATIONS-- LRU 1 HOLE DOWN FROM TOP, LRL 1 HOLE UP FROM BOTTOM, RRU 1 HOLE DOWN FROM THE TOP, RRL TOP HOLE. 5TH COIL--34" OUT, 350 LB, 1/4" PRELOAD 13" LR DROOP WSR-2 TIRES ON ALL CORNERS, 5" BS, LF 8#, RF 10#, LR 6#, RR 9# %'S-- LEFT 53.4%, REAR 54%, CROSS 51%, 110# BITE. Now to the problem. The car is average/good early in the night, as soon as the track dries out it goes to bad. The car has no side bite and little to no forward bite. We race on a 3/8 semi banked track, on super slick this car will skate from bottom at corner entry all the way to top by the center. Our driver seems to have to wait forever to pick up the throttle regardless of his corner entry. It seems like the car wont stick on the RF. We have battled this problem for awhile and we are looking any help we can get. I know a lot people are thinking that the obvious answer is driver, but we have had 3 different drivers with the same results.

[TheJet-09]

I by no means have all the answers, but I will say that at first glance your RR ride height is way too high (should be 7 3/8" from what I understand). To help tighten entry you can also lower the RRL bar (looks like you have it in the top hole). Are you moving the RR forward at all in the slick (shorten both rods 2-4 turns)? Your RF spring also seems too stiff. I attended the MasterSbilt class this winter and Keith said the only two RF springs you need are a 350# and a stack. Running just a spring on the RF (no rubber or stack set-up), I believe some guys are going as soft as 275#. You might also try a 225 RR spring and a 200 LR. I know it might seem to contradict what you are trying to accomplish, but the 200 requires more pre-load which can help get the LR up on the bars. The last thing I thought stood out was your shock PSI on the RF. It appears to be a tie-down shock, but at only 35 PSI I'm not sure it will actually do that. Lastly, lastly...assuming you have lead in the car, where is it or where do you move it when the track slicks off? That's my two cents...or should I say "sense"?

[hpmaster]

The 07 smackdown I set up has softer frt. springs, 450LF and 375RF as our base setting, we use softer RFs and bumps on slick, never below 300lbs. Also your upper bar settings are all higher on the frame than we ever have used. As for bars I like degrees of angle better than what holle you are on when talking bar angles. We use rear staggers around 4.5" to as high as 6". Our RF shock is at 75 lbs. I have for years used the rule if the car won't turn into thru the middle go softer on the LF spring. JMHO

[TEAM56RACER]

I screwed up my first post the RF spring rate, it is a 350# not a 500#. I will check the exact angle of the bars and see where it is right now. When I drop the RR frame height down its puts 160# or more of bite in the car, it also puts the LS % at around 55%. What TheJet-09 said about going softer on the LR does make sense, because the car does seem to be "lazy" about getting on the bars. I am going to up the pressure on the RF shock, I just started @ 35 psi to see how it acted. I haven't tried moving the RR yet. And as far as lead goes, its got 20lbs low right behind driver, and 20lbs just left of 90/10 shock mount, and 40lbs behind the dry sump tank. I have not tried moving it around too much.

[TheJet-09]

When you mention the wedge/bite increase with lowering the RR ride height, are you not adjusting the LR as well? The 8.25" you first mentioned as your LR ride height also seems high (at least to me). I think mine is around 7 5/8" - 7 3/4". As for the lead...I would remove/move the 20# behind the driver. Unless he/she's only 120# themself, it's not helping transfer to the right. Maybe move that piece to the top of the bar that the rear shock mounts are welded/clamped to. Also, when you mention the 90/10 shock location, are you just using it as a reference point or do you actually run a 90/10 shock? Lead behind the drysump tank seems like a common place from what I see on other's cars. I guess try getting the lead "up" in the car and between the four corners (shock/spring locations)...you should be okay.

[Matt49]

Swap your rear springs and I bet it comes to life. Stiffer RR will get you more side bite and softer LR will help get the car up on the bars and provide you with the drive you need.

[TEAM56RACER]

Matt49 Thanks for the advice, I did go to a 200# LR spring, I didn't swap springs I left the 200# on the RR, I will put the 250# on the RR tonight. How much difference does the spring length make on the rear?

[Matt49]

Matt49 Thanks for the advice, I did go to a 200# LR spring, I didn't swap springs I left the 200# on the RR, I will put the 250# on the RR tonight. How much difference does the spring length make on the rear?

Sorry I should have been clearer. I didn't mean to literally swap the rear springs but to swap the spring rates. Spring length doesn't affect handling until you start encountering coil bind issues or bowing problems. Most guys run a 14 inch spring on the LR and 12 inch spring on the RR.

[hot rock]

How did the 250 rr work out

[TEAM56RACER]

I ended up staying with the 200 spring on both sides. The car was still way too loose off, the track was dead slick. I started the feature on 2 new rear tires, the left tire was still like new after the race and the right side tire showed alot of wear. I'm going back to the drawing board. I guess I will just load it up with a ton of bite, and I'm gonna go up to 450 RF spring. It had 125# of bite in it.

[7uptruckracer]

You said your RLB and Both Uppers are one hole from top and the RLB is in the top. Knock the RLB down a hole as well as your RUB and Index the LRU bar on the birdcage the 450 RF you probably won't like at all.... Put more LRF compression and gas into that shock

I ended up staying with the 200 spring on both sides. The car was still way too loose off, the track was dead slick. I started the feature on 2 new rear tires, the left tire was still like new after the race and the right side tire showed alot of wear. I'm going back to the drawing board. I guess I will just load it up with a ton of bite, and I'm gonna go up to 450 RF spring. It had 125# of bite in it.

[TEAM56RACER]

I ended up this weekend with radius rods at LRU in the top, LRL 3 up from the bottom, RRU 1 down from the top, RRL 1 up. The car has the 4 hole mounts on the frame.

[manwplan]

One thing I notice is you make mention that when you lowered your RR ride height you gained LR bite and LS %. Something isn't adding up. In general you can't change the left and rear % with out physically moving weight around. To have a 1.5% change in LS just by lowering your RR doesn't make sense.

[Matt49]

How much ballast do you have bolted on? Where is it all mounted and at what height?

[hot rock]

How was entry this wk
IS CAR FLAT OR ON BARS KINDA HIGH ON ENTRY COULD BE BOTH LR BARS BEING HIGH HOLDING A LOT OF STEER
MY 05 SMACK WHEN I SAW THE TRACK DRY OUT I WOULD GO TO BOTTOM HOLES ON BOTTOM BARS BOTH SIDES CLOSE TO SAME SETUP I RAN A 225 ON RR AT VERY SLICK BANKED TRACK I WAS TOLD NEVER TO DO THIS BUT STARTED WINNING AND RUNNING STRONG ALWAYS TRYED OTHER THINGS DIDNT WORK AS WELL
MIGHT TRY RUNNING A WHEEL SPACER ON RF OR LR IN SLICK
WHAT TYPE OF 5TH COIL SHOCK MAKE SURE ITS STILL WORKING
MIGHT ADD MORE REBOUND IF LOOSE ON ENTRY STILL GOT TO FIX ENTRY FIRST

[TEAM56RACER]

Entry was better, the car got on the bars better than normal. It would enter on the bottom pretty good, then from the center off the driver would just have to chase the RR up the track. And as far as lead goes, its got 20lbs low right behind driver, and 20lbs just left of 90/10 shock mount, and 40lbs behind the dry sump tank, 30lbs on the front ballast clamps that hold the fuel cell in. Overall the changes that we made seemed to help it. Its just got to drive off the LR more than it did.

[7uptruckracer]

If he's chasing it up the track it sounds like to much rear steer or rear trail. Drop the LRL down a hole or it you have the Right side bars lengthened undo it. You don't want to lose your entry but I would drop the LF to 450 it will free up entry but when you take the rear steer out for your exit drove and tail out feeling that will still allow it to get in. I'd look at the LRL unless your not dropping the LR on entry and holding rear steer in if you are drop the RRU bar the second hole from bottom if it's 4 bar and seriously look at indexing on the LRU birdcage it's a very effective change. What is your shock setup?

[7uptruckracer]

Definitely post your 5th coil travel I saw you said it was a 350 at 34" post what motor your running too that derives most your drive and the bars tune the balance of it

[TEAM56RACER]

7uptruckracer, I'm not sure how much 5th coil travel it has in it right now, I'll check and get back with you on that. The current motor is a steel block, brodix headed 358, 650hp. The other motor that we run is an all aluminum 420, there is about 150hp difference in the motors but you sure can't tell it with the way the car is working now. So for now the little motor is plenty. We won the heat by a straightaway, track had some moisture and the car worked pretty good. Started 3rd row inside in the feature, track was slick. Although we are getting closer we still finished 5th and not much improvement in forward drive. I took roll steer out, added LR bite and also went to the 450 RF spring. I'm limited on how much rear stagger I can take out, its either 4" or all the way down to 2". Would 2" of rear stagger be enough? It sure seems like it could get away with a lot less than 4"

[7uptruckracer]

The 5th coil and shocks could be your key. Unless your at a high speed banked track most won't be as stiff as that 450 RF, most my cars are 350-375. While it might be looser off i tend to think of loose and drive as related but a little different at the same time over rotated and the inability to go forward are two different problems. I would stick with 4" definitely shoot for the closer side to 4" of 5th arm travel if you don't have it change your 5th coil spring 25# at a time till you do As far as how forward for back it is you want far enough back for traction until you get wheel spin from to much instant, High HP motors are normally farther forward around 38" and lower like stock heads or crates are farther back, but still the same travel range 3-4" the more travel the more torque your absorbing so he can throttle up without shocking the tires. Sounds like your doing well just need to keep up with the changing conditions more.