Driving in deep

Running limited mod class. The car handles pretty dam good if i am able to roll into turn and get back in it throught the rest of the turn. Car pushes real bad if I am forced to drive in a little deeper when on the outside.
What is it that I should be looking at for the cause of this.
car is :
56 % left
54 rear
50 lb bite
3 link 2 bbl limited mod. solid pull bar at 17.5 degree
.75 rt rear trail static
10 degree up rt lower
25 degree up left lower arm
j bar even at pinion with 4 inch RAKE
I know we dont have the HP to get the car up on the bars so easy and rolling in helps set it up better than driving in hard. ( NO BRAKE FLOATERS ALLOWED TOO )
But some guys relized my problem last year and took advantage of it. I need some ideas on some posible changes TO ME OR CAR !!!!

Any Sugestions ???

I would think you need to take some lr bar angle out or if the pull bar is not centered on rear end or at the front try that. You could raise the rr bar, that would help but might hurt your side bite. Good luck.

Sounds like a lot of LS weight and a lot of LR bar angle and a lot of RR static trail. You didn't mention anything about track size or banking or gear ratio or what spring rates you have.

Running a 3/8ths 10 degree bank long sweeping turn track
600 lf -4 shock 650 rf 3-5
175 lr -3 shock 150 rr 4
my right low bar is set so when car is at lowest shock travel the bar is FLAT
Left Lower is set high because if I didnt the car had a nasty PLOW PUSH anytime I was on the gas. The pull bar is in the center BUT I did buy the Jet Mod adjustable bolt to move it around a bit.
ANYTHING else to try I have a practice coming up this weekend so I can try a few things.
I am also gonna go from a 6.0 gear to a 5.43 to drop so rpm. They are going to a 7k limit this yr. was turning 7500

you ever try running a stiffer spring and stiffer comp shock on the lr? should help the car turn on entry a little better.

the other guy said it first... way too mush ls% you roll out of the gas and the ls% helps it rotate but if you drive in harder and are more on the gas it doesnt settle back to the ls and help it turn. remove LS% and see how it does when you drive it in deep/on the gas.

Slight dilema on left side %.
There is no bolt on weight on car. Fuel cell is in middle. The only thing I can move is the battery.
Right now it is mounted behind the seat area up high. Would moving that to the rt side Hi help it. or should I mount it low on the right side.???

Ill be the 3rd to say way too much left side %. Ive always been told to never take left % higher than the rear % on a mod. LR bar angle could be a problem, but have seen some wild angles on bmods. Bite sounds a little low for a 3 link also, most seem to be atleast 80-140 lbs of lr bite.

If the driver is above 220 lbs, this is prolly for the high left side. Ive been told if the driver is above 220, add the difference straight across from the drivers rear on the right side. This way it makes the car feel like a car does with the driver weighing less than 220. Heard some say 200 lbs is the weight to start doing this, but I started doing it at 220 because that was the number I heard the most. JMO

Quote:

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Originally Posted by BCR

Slight dilema on left side %.
There is no bolt on weight on car. Fuel cell is in middle. The only thing I can move is the battery.
Right now it is mounted behind the seat area up high. Would moving that to the rt side Hi help it. or should I mount it low on the right side.???

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Can you move the fuel cell or is it maditory to be centered? Also how high is the cell and can it be dropped or raised in the chassis?

As far as the battery, Id place it low. But that just my opinion because it sounds like your getting alot of transfer

I am 225 actually and these scale numbers are with me in car. The cell would have to be redone in order to move it.

What about wheel offsets.They are the easiest way to get rid of left side.If you can move the left wheels away from the chassis centerline and move the right or just right rear in it would change the left side pretty drastictly.

I agree. Move the battery and square the rear end. Get the car back to a more balanced set-up. What do you mean by no bolt on weight? Not allowed or don't have any? I'd get that split valve shock off the RF and that 3 valve off the LR. Put 6's up front and 4's in the rear. If it slicks up, put the 93 back on the LR if you need more drive. If you can, I'd try evening out the springs, too. 650's front 200's rear. You carry a lot more speed into the corner on the top, obviously, and you've got more or less a bottom groove set-up. That rear end that far out of square isn't helping matters any. Don't forget to "roll" off the throttle and carry momentum farther in the corner before "easing" back on the throttle. Sounds like a momentum type track, so you have to remember to drive it that way. You're going to be dropping some RPM which is going to tighten you up a little more in the middle of the corner when you ease back on the throttle. So, if it does get tight, try rolling it in farther past the middle before picking up the throttle again. Good luck.

Ty guys. I will try some of this this weekend and post back.

OK went to track this weekend.
I lowered the left side % to 55. Car turned and went thru alot better I think.
Delima. They removed the spoilers from us now I realy have no foward. I couldnt use more than 3/4 throttle. Even going down the straights if I got full throttle. The tires would just spin. but car was turning realy well.
What could I do to it without sacrificing to much.
Would putting more pull bar angle ( long bar style ) in it help. Even getting off the turn was a little on the loose end.
I am at 17.5 - 18 degree rite now on the pullbar angle.

I would change your shock package myself, some great reading.



Stated simply, I use shocks to alter/adjust/change a condition known as, "Instantaneous, Dynamic, Diagonal" - hereinafter refered to as "IDD".

The Cup guys get into suspension lockdown and other concepts for aero purposes, but my work is on the short tracks where the car often comes in with slightly different "aero" shape than it went out with after a 15-lap qualifier .

Okay, got your fresh cup of coffee and a notepad?????

Picture a car sitting on four wheel scales. This car has absolutely equal weight distribution, so all four wheels weigh exactly the same.

Now, if you were to push down on the exact center of this car, all four wheel scales would increase equally.....everybody agree?

If I were to add shocks to the RF and LR that had high - or higher compression values, and I pushed down on the center of the car, what would happen????

That's right....The RF and LR scales would show momentary increases over the other two scales due to the resistance of the two shocks, but everything would even itself back out again after the shocks bled down, and all four wheels would be equal in weight again......OKAY???

What happened here was a change in the IDD. For just an instant, there was more diagonal - or crossweight - with the RF and LR momentarily being more heavily loaded than the other two wheels.

But, once the shocks bled down, the setup returned to the equal-wheel-weights setup.

Now, go the opposite way.....lift slightly on the car.

All four wheel scales should show equal reduction of weight on all four wheels.

Add shocks with more REBOUND to the RF and LR, then lift again.

The RF and LR scales should show a momentary, increased reduction of weight over the other two scales until the shocks allow the wheels to go into full droop.

In this case, we have, momentarily, reduced the diagonal - or crossweight - for an instant.....

......which explains - for those of you who have read the Penske shocks setup manual - the suggestion to set the car up with a slight push on turn entry, dialing it out with LR rebound.

LR rebound induces a momentary reduction of crossweight upon turn entry, but allows the suspension to return to its original setup for turn exit.....effectively giving you one diagonal - or crossweight - for turn entry and a different one for turn exit.

A reduction of RF compression would probably serve the same purpose, but I am most comfortable working with rebounds - although I WILL monkey with compression when my back is against the wall.

With the right shocks, you could actually instantaneously DECREASE the diagonal or crossweight for turn entry, and INCREASE it for turn exit - or vice-versa.

The above is an over-simplified example of how it SHOULD work, and as we all know, nothing in racing is really "simple."

But, if you can get the concept of "controlling" body roll or weight transfer out of your mind, and visualize instantaneously - and momentarily - increasing or decreasing the diagonal or crossweight for better turn entry or exit, and you SHOULD begin to grasp the concept of shock tuning....