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IMCA Stock car is loose into and off the corner when the track is dry handles well when there is any moisture at all. Springs are LF1000 RF900 LR225 16" RR200 13" car has 51.5 left 54.5 rear has 130lbs bite. Would like to know what changes to make to get the car tighter into the corner when the track slows down.
If you are running 3 wheel brakes, that might be your loose entry problem.
Springs are close. If you swap the fronts that would tighten exit but will loosen entry even more.
Tighten entry: Move RF wheel out and/or LF wheel in. Less spring in RF. More stagger
Tighten exit: More spring in the RF. Less spring in RR. Less stagger
Make sure nothing is binding in the suspension. Usually they are tight in and loose off or either loose in and tight off.
Loose when braking into corner or still on the throttle entering corner ? Percentages with driver in car ?
Not running 3 wheel brakes. Loose when off the throttle coming in. Percentages are without the driver. I've been considering increasing both front springs 100# or decreasing both rears #25 to keep the balance the same would either of these help?
Depending on driver weight and seat placement, you could be heavy on Left side % and Rear % and have a lot of Bite with the driver in the seat. Too much bite or too much Left side % will make it loose on entry. I would scale the car with drivers weight in the seat and see what you have.
I would scale the car with the driver in the car and see what your percentages are. We have had our best luck with front springs in the 1100 to 1150 pound range in the left and right. We usually run 200 pound springs on both sides in rear. 16 inch on left and 13 inch on right. Left rear bite seems to be a driver preference. I like around 200 pounds. Weight placement seems to be very important on these cars because a lot of weight has to be added to make weight. Where is your weight mounted. I do not claim to know everything, just telling you what has worked well for us.
Ok I have considered going stiffer on the front springs I'm not getting too much movement currently, right around 2.5-3.0 on the rf but I suppose there is a chance I could get more movement with a stiffer spring if it plants the tire better. Battery is mounted on top of lr spring bucket. There is 150 under the fuel cell right at 50 in front of the cell then I've got 50lbs on the lr next too/ahead of the cell and 40 to the right/ahead of the cell
If possible try moving half of that 150 lbs that is under the cell up higher and forward. Low weight can cause a car to be loose in and weight too far back can cause loose in. Getting all that weight in the correct position seems to be the trick to balance these cars. We found that it needs to be spread out. Not all low or high. Not all on the left or right. 300 lbs in the wrong place is hard to compensate for.
you don't mention cross %. I'm guessing with that much lr bite your cross is high
To be honest it sounds like you need to look for binding in the suspension if you are not getting much movement in the front. We run the same springs in front 1000 LF and 900 RF as you are and similar in the rear.
52.5 left, 52.5 cross, 54 rear %'s. 3,000lb car. All with drivers weight in the car. No weight jacks. 2" offsets all around most of the time. Our car gets better the slicker the track gets because it is usually too tight when tacky.
Just curious what makes you think 3” isn’t a lot on what is perceived to be a STOCK IMCA car, aren’t the shocks mounted in stock location? That shouldn’t be too far off max travel for a stock deal if memory serves me correct? If the rear end is locked look at stagger. You don’t need big swings if car isn’t that far off. Me personally I never ran that much rear or that little left on the cars I setup I was around 54-55 left and 52 rear but that’s with driver make sure you don’t have to much weight behind axles or it will swing the rear end out pendulum effect. You want better polar moment.
Quote:
Originally Posted by racing08
We dont run stock shocks in imca stock car. They can be mounted outboard just like on a modified. 3 inches of travel on the rf is what I shoot for and then adjust from there. 130 is on the lower end of bite for what I've ran in my car when scaling without me in it. Typically for slick I will put 1 or 2 rounds of wedge into the car if I dont think I'll be tight enough, dial in a good bit of front brake and back my entry up to make sure to get through the corner squared up. What are you currently adjusting when the track gets slick? Moving some ballast forward certainly will help tighten entry. 54 rear is not uncommon for these cars these days, especially for the slick
move weight up. all weight should be at or above rear frame rails.
sounds like your car needs to scotch better on entry, which would mean moving some weight closer to rr tire.
how big is fuel cell? is it mounted as high in the car as it can be? like filler neck right below trunk. Car sounds like it is not transferring any weight to rr.
if you have a lot of low left weight (like post above mentioned) get rid of it that low and move it up, as high as possible.
No LEAD behind the axle.
Mount your lead shoulder height BETWEEN the 4 weight jack bolts and re set all the ride heights.
I ran no more than 51 rear, but I also ran 200 bite, search my user name there are some posts I didnt erase still on here. your rear springs are too soft if you ask me. Id put 250s in there.
Id search other people also posting in this thread before I took their advice.
cross is a reference for pavement carsQuote:
Originally Posted by Fox_hunter42
Bite is what dirt racers use.
Who do you recommend for a shock builder or starting shock rates?
5050 8060 8040 flatter track or momentum
3030 3030
bilstien
bob harris for high end shocks
wade cross for bilstien budget minded builds
Talked to Bob Harris and he said he could build me a package to fit my driving style and would probly only need 6 shocks thanks for the info.