Educate me about springs

[Lastminuteracin]

My car is an 86 Anson Supervee. Resurrected from a box of parts. Springs on the car are 425f and 550r. Old set up notes that came in the boxes show the car was run 425/600, 425/900 and 600/900. My butt is telling me at 425/550 the car is just glued to the track. It goes where I point it. At Sonoma it had a very slight mid corner push in the slow turn 11. One notch on the front sway bar cured it. I just feel that I need to “free” the car up overall. It’s too “mushy”
Will stiffer springs achieve this? I figure going up 30% to 550/700 would keep the front to rear % almost the same. If i did this would I need to stiffen the sway bars equally? Or will the bat balance remain as is?

[teamwisconsin]

Lap time? For that car at Sears, until you get under a high 30 (say 1:38-ish) it's going to feel pretty ok regardless of what springs it has. And until you get sub 1:35 you could have all sorts of spring combinations that would "work". Good driver/good tires/clear track/nice day that car should be able to be under a 1:32. Don't tune any car for balance in T11. If you are hugging the inside the whole way around in a formula car, you're doing it wrong. Use a healthy dose of trail brake into the corner until it feels like it's about to spin; rotate it at once, then be hard on the power and drive it out on the gas.

Tunneled cars can really utilize bump stops and packers. For my fast drivers in Atlantics and SV's, I'll set the car up to run on the springs until the downforce takes over and the car is sitting on the bump stops. I like the 32 gram Penske ones for my RT4's and 5's.

[Lastminuteracin]

1:38’ish…not even close ?
So much to learn still. I do take 11 with a late turn in and a late apex to try to get it pointed straight and back on the gas earlier. Trailbraking I have not tried. My current (Mintex) pads suck. I have new KFP’s on the way for the next outing. Everywhere else on the track the car is planted and turns well.

[Hardingfv32]

Free up, mushy, planted? What do these these mean to you? Oversteer or understeer?

You really do not find these terms in the engineering books.

Brian

[Lastminuteracin]

Free up, mushy, planted? What do these these mean to you? Oversteer or understeer?

You really do not find these terms in the engineering books.

Brian

Thanks for the reply. I come from 40 years of karting. I’m trying to wrap my head around the dynamics of a sprung vehicle with an open diff vs a Superkart with a straight axle and a chassis that is effectively “the spring”
I now realize that the springs are more to retain ride height and conformity to the track surface than actual fine tuning.
I think Ethan is correct in the fact that I probably haven’t pushed the car hard enough to really illicit any bad characteristics. What I would like to feel is a slight bit more oversteer. Getting out the Carrol Smith book (which can make my head spin) leads me to believe the easiest way is to achieve this is by playing with the sway bars and not the springs.

[John LaRue]

Thanks for the reply. I come from 40 years of karting. I’m trying to wrap my head around the dynamics of a sprung vehicle with an open diff vs a Superkart with a straight axle and a chassis that is effectively “the spring”
I now realize that the springs are more to retain ride height and conformity to the track surface than actual fine tuning.
I think Ethan is correct in the fact that I probably haven’t pushed the car hard enough to really illicit any bad characteristics. What I would like to feel is a slight bit more oversteer. Getting out the Carrol Smith book (which can make my head spin) leads me to believe the easiest way is to achieve this is by playing with the sway bars and not the springs.

It might be worth putting someone experienced in the car, Ethan or even VFP (Vince "F" Puleo ) and have them get it close. It is much easier, not to mention safer and less expensive, to learn in a car that has a good set up than one that is in left field.

[S Lathrop]

A bit of advise:

When ever you change spring rates, you need to adjust ride height so that you maintain the same dynamic ride height

Adjusting the rear ride height is the first tuning adjustment I use and until I get the best performance from a combination of rear springs and rear ride height, I do not make any other handling adjustments.

If you just change a rear spring rate, you are making 2 changes at the same time. You are changing the rear spring rate plus the rear dynamic ride height. Put a stiffer spring on rear and leave the ride height un-changes, you have stiffened the rear of the car and raised the dynamic ride height.

The dynamic ride height is the ride height the car oscillates around as you drive around the track at speed.

[E1pix]

Neat to read that Vince Puleo is still active.

We’ve both shared photos on the OldRacingCars site, and both raced in the IKF Grandnationals in 1981. Beyond, we don’t know each other.

I love the history of racing, always will, and it’s good to hear he’s still out there and racing.

[Lastminuteracin]

Neat to read that Vince Puleo is still active.

We’ve both shared photos on the OldRacingCars site, and both raced in the IKF Grandnationals in 1981. Beyond, we don’t know each other.

I love the history of racing, always will, and it’s good to hear he’s still out there and racing.

VFP has pretty much been with me for this entire journey. From picking the car up to being at every outing. He’s been trying to get a medical signed off but Kaiser won’t do it.

[E1pix]

Oh the continuing irony being you’re an Anson owner, Jim...

You may recall I was trying to rally an Anson registry a couple years ago, via Mike McHugh, but his records are scant and I moved on to other things. Great guy, regardless.

Please tell Vince I’ve enjoyed his F5000 images, taken at the same time I was doing the very same as a fellow teenager at Road America.

Edit: Sorry for going off-topic

[Offcamber1]

I'm not a chassis engineer, there are plenty of those that have chimed in here, but it seems to me two big factors to be considered are:

1. What compound of the tire used? Are you actually getting them up to operating temp?

2. How much experience does the driver have in gaining the max out of the package?

Again, i am not an expert by any means, but it seems to me starting off soft to slow up transition times from straights, to braking, to cornering, makes sense?

I have no idea how the front/rear wing angles affect all this, so maybe start with a lot of downforce and trim it out as you get more comfortable?

What a fun problem to solve!!!

Kip

[teamwisconsin]

VFP has pretty much been with me for this entire journey. From picking the car up to being at every outing. He’s been trying to get a medical signed off but Kaiser won’t do it.

Kaiser stopped doing race physicals a couple years ago. It’s so dumb. The form puts no liability on the doctor, but they aren’t willing to risk it. I actually went to Planned Parenthood for my race physical a couple years back. Got some odd looks from the staff, but they signed off.

[S Lathrop]

When I choose a set of springs I want to know the motion ratio of the spring/shock movement to the wheel movement. This is step one.

Step 2 is knowing what the corner weights are.

If you take the motion ratio squared and times the spring rate you get the wheel rate for a given spring. With the wheel rate for the spring, you can calculate a ratio of the spring rate at the wheel to the load of the car on that corner/wheel. This is important because the pitch angle of the car is a big determinant in how the car will handle as you go through a corner. In general a car will push when the rear is low and be loose when the rear is high relative to the front. Getting the spring balance optimized is the first step in getting the car handling as you want.

Changing the spring rate by say 50 pounds per inch will give a very nice, incremental adjustment to the handling. As you raise the spring rate on a corner you need to lower the ride height by some increment to keep the dynamic ride height, constant. That is the ride height the car oscillates about as you go around the track.

I may not have explained this any better than I did last time. I learned this spring changing technique from oval track racing where we would change springs to tune handling and were time limited so when we went back on the track we were as close to the optimal setup as possible and did not need to do repeated pit stops to get the balance optimized after a spring rate change.

[DaveW]

Kaiser stopped doing race physicals a couple years ago. It’s so dumb. The form puts no liability on the doctor, but they aren’t willing to risk it. I actually went to Planned Parenthood for my race physical a couple years back. Got some odd looks from the staff, but they signed off.

I get my race physical along with my Medicare annual physical at my primary care office that is part of the University Hospitals Medical Group. They have no issue filling the required parts out for me. I get my annual eye exam close to the same date and so they fill out the vision part.

[Richard Hybels]

VFP has pretty much been with me for this entire journey. From picking the car up to being at every outing. He’s been trying to get a medical signed off but Kaiser won’t do it.

I’m a Kaiser member and they are just a pain trying to get a racing physical. I got my last physical in combination with an FAA class 3 by Dr. Toth in Concord, Ca.
I don’t have any outstanding issues but over the years Kaiser seems to be scared of lawsuits. When a regular Kaiser Dr. would do an SCCA physical for me he would refuse to do the simple eye test.

[Richard Hybels]

It might be worth putting someone experienced in the car, Ethan or even VFP (Vince "F" Puleo ) and have them get it close. It is much easier, not to mention safer and less expensive, to learn in a car that has a good set up than one that is in left field.

Ethan has been known to do that from vintage F1 on down.