Shock Help

[Gratefuldiver]

Im currently using single adjustable Vari shocks all the way around. I think Im at the point where adjusting them up anymore in the rear will make the rear to stiff and cause me to spin even more during auto x. My times are fairly consistent (consistently bad, but consistent none the less LOL) So Im looking for ways to improve the car. Ive stepped up to AZENIS RT615K over the Nitto 555 (rear) and cheap coopers (front) I was using but am thinking some double adjustable Vari's may help. At the same time Im having a hard time with the cost, are they going to help enough to justify the $600 they cost? I guess in the end its a personal decision but Id love to hear what you guys could add.

72 GTO w/vert frame
461 Stroker w/th400
SC&C Stage 2 plus kit
275/40/17 RT615K all the way around (yet to run)
Hellwig tour pro hollow bars w/adjustable rear (set in middle)
Vari single adjustable shocks (set at 11 front and 9 rear)
Baer Track 4 front
Wilwood D154 rear
Alignment= -2deg camber, +4.75deg caster, -0.9deg total toe

[Rod]

I think Im at the point where adjusting them up anymore in the rear will make the rear to stiff and cause me to spin even more during auto x.

Hellwig tour pro hollow bars w/adjustable rear (set in middle)
Vari single adjustable shocks (set at 11 front and 9 rear)
Alignment= -2deg camber, +4.75deg caster, -0.9deg total toe


looking at the basic setup you have listed, it seems ok...so before you throw money at a problem .....have you tuned the car,,,find an empty parking lot and chalk out a basic 180 degree turn,,,

Personally If I was to start with your car and tune what you have
1) disconnect the rear sway bar

2) I would turn the front shocks up full and drive, the handling will suck and then back them down 3 clicks at a time..it will get better then when sucks again...now your close the turn up one click at a time till it feels good again...........now repeat this on the rear shocks

3) now hook the rear bar back up on the softest setting...and test again

hope that helps

[Gratefuldiver]

No I haven't tuned to that degree. I think that's another one of my problems, identifying the issue and correcting it with what I have. I figured that would come with time. I will look at trying to dial the shocks in at the next T&T, my luck I would find an empty lot, start to tune and promptly be awarded a CNI from the man.

[Rod]

No I haven't tuned to that degree. I think that's another one of my problems, identifying the issue and correcting it with what I have. I figured that would come with time. I will look at trying to dial the shocks in at the next T&T, my luck I would find an empty lot, start to tune and promptly be awarded a CNI from the man.

ha ha ha ha ...yep that could happen...tell him you doing safety test... I have used that excuse before

[nokones]

There too many varibles in the equation to provide an accurate response over the internet. Shocks, spring rate, sway bars or no sway bars, tire pressures, tire brand and size and age, wheel size, vehicle weight distribution ( cross-weight precentage) come into play here and also one most important factor is the problem enhanced or induced by the driver as the primary or contributing cause of the handling problems. You may have a whole slug of problems and not realize it. You need a hot shoe driver take the car for a run and/or take the car to a suspension tuning shop that can get the car in the ball park and you dial in the rest. You will need to exercise a lot of patience in order to get it dialed in

[Gratefuldiver]

I would welcome the opportunity for an experience driver to take my car out. The auto cross group in STL is not the biggest muscle car group. I can think of 3 guys

[Rod]

I would welcome the opportunity for an experience driver to take my car out. The auto cross group in STL is not the biggest muscle car group. I can think of 3 guys

your in STL area? I might be doing some work up in IL around January... at a shop there, if so I could try to set aside some time to review the car

[Gratefuldiver]

Wow thanks, that's a generous offer! The weather would be a big X factor in January. With midwest winter it could be 60 deg on day and -10 the next so you never know. I'm about 35-40 min from Gateway on the IL side.

[Rod]

Wow thanks, that's a generous offer! The weather would be a big X factor in January. With midwest winter it could be 60 deg on day and -10 the next so you never know. I'm about 35-40 min from Gateway on the IL side.

your car have coilovers?

[David Pozzi]

The 555's are not that great for autocross. Nice on the street but you won't get good autocross times with them. The NT05's are good and the Falken's are very good.
I don't like mixing tires but I understand economizing so you can run, I did that for many years. I would have put the Falken's up front to gain the best advantage. Look around for some used take-offs from the better financed guys. Frequently at the end of the season guys sell off their excess tires.

[Gratefuldiver]

your car have coilovers?

No, coil springs and shocks


There too many varibles in the equation to provide an accurate response over the internet. Shocks, spring rate, sway bars or no sway bars, tire pressures, tire brand and size and age, wheel size, vehicle weight distribution ( cross-weight precentage) come into play here and also one most important factor is the problem enhanced or induced by the driver as the primary or contributing cause of the handling problems. You may have a whole slug of problems and not realize it. You need a hot shoe driver take the car for a run and/or take the car to a suspension tuning shop that can get the car in the ball park and you dial in the rest. You will need to exercise a lot of patience in order to get it dialed in

Vari single adjustable shocks
Front Hotchkis coil springs 580 lb/in
Rear SPC coil springs 135-150 lb/in
Hellwig Pro Tour hollow sway bars
Tire pressure was normally 32 hot
Cooper Zeon 275/40/17 front
Nitto 555 285/40/17 rear
Tires are about 3-4 years old with 6500 miles (installing four 275/40/17 Falkens this winter)
Wheels are 17x9.5 w 5.5 BS
Car weight about 3500? No clue what the cross weight is. Guess I would need a set of wheel scales for that
Driver, one year of auto cross experience.

[nokones]

Don't forget about all the rear suspension bushings and control arms. If you are still using OEM rubber bushings that will contribute to the problem. If your rear control arms are flexing, that could be another problem. I do not have any experience nor do I have any knowledge on the Vari shocks. Are these the shocks that Ridetech uses in their line of products? If so, I would contact them and ask them for some technical help with your shocks. You need to have the right valving for your particular car if you want them to work on autocross courses. You may want them to revalve the shocks for you. Just make sure who ever works on your shocks that they have current autocross experience and data so they will know how to revalve your shocks.

If you're in the neighborhood, you can come by put your car on the scales. However, you won't be able to adjust any cross weight unless you have coilovers or jacking points

[UMI Tech]

It's a minor detail but you can soften the Hellwig bar one hole and have less of the "rear stepping out".

Depending on how deep you want to get into this, I'd recommend reading the Ron Sutton handling information posted in this section. Ron makes cars win.

For driving, it's definitely an eye opener to have a pro drive your car and then ride with you and give you tips. I learned a ton from Brian Finch and Sam Strano this past year. I also learned there's still a lot more to learn...

ramey

[BMR Sales]

Wow thanks, that's a generous offer! The weather would be a big X factor in January. With midwest winter it could be 60 deg on day and -10 the next so you never know. I'm about 35-40 min from Gateway on the IL side.

Take Rod up on his offer! Heck he will teach you things in the Snow that you will use in the Dry!

[Gratefuldiver]

Don't forget about all the rear suspension bushings and control arms. If you are still using OEM rubber bushings that will contribute to the problem. If your rear control arms are flexing, that could be another problem. I do not have any experience nor do I have any knowledge on the Vari shocks. Are these the shocks that Ridetech uses in their line of products? If so, I would contact them and ask them for some technical help with your shocks. You need to have the right valving for your particular car if you want them to work on autocross courses. You may want them to revalve the shocks for you. Just make sure who ever works on your shocks that they have current autocross experience and data so they will know how to revalve your shocks.

If you're in the neighborhood, you can come by put your car on the scales. However, you won't be able to adjust any cross weight unless you have coilovers or jacking points


UMI Adjustable Upper Control Arms- w/ Roto-Joint
After Market Boxed lowers with poly
Vari shocks are Alston's Chassisworks Brand

[rustomatic]

For such a substantial car, your rear spring weights seem really super-light. My Falcon is barely surviving what I think are 150-pound leaves in the rear, and it weighs several hundred pounds less than your GTO; I'm wanting 200-pounders. While I'm not indicating that you need crazy-heavy springs in the back of your goat, it would undoubtedly benefit from heavier rear springs. On some level, this might help in the avoidance of un-weighting the rear corners of your car when you dive into a turn...

With a big block, I'd think that you'd need to be closer to 700 in the front...

[Gratefuldiver]

The rears are pretty much a match for the front. A Pontiac engine isn't really a big block or small block. It fact 350-455 is pretty much the same block with different machining. I originally went with those front springs because everything else lowered the car to much.

I guess just because they are matched doesn't mean they are perfect for auto x. I'd assume Id have to go coil overs to get much more

[nokones]

The springs may or may not be too lite for his current setup. It all depends which suspension theory you want to run with. Heavy springs and soft sway bars or soft springs and humongous bars. (The Herb Adams concept or the non-Herb Adams concept.) Of course the shocks will need to be valved correctly to complement the spring and sway bar package. You won't know until to throw the car into a curve or through a slalom, then you start working on the problems.

[Gratefuldiver]

Bringing this one back,

If I had the chance and money to add coil overs in the rear would it be worth it? That adds a whole set of questions about what coil over system. Ride Tech has 4 different set ups and Vari has one. Looking at https://www.cachassisworks.com/p-1152-chevelle-64-72-gm-a-body-rear-coil-over-conversion.aspx and Ride Tech set ups http://www.ridetech.com/store/1964-1972-gm-a-body-coilover-rear-system-triple-adjustable.html http://www.ridetech.com/store/1964-1972-gm-a-body-coilover-rear-system-single-adjustable.html

[Carl @ Chassisworks]

Bringing this one back,

If I had the chance and money to add coil overs in the rear would it be worth it? That adds a whole set of questions about what coil over system. Ride Tech has 4 different set ups and Vari has one. Looking at https://www.cachassisworks.com/p-1152-chevelle-64-72-gm-a-body-rear-coil-over-conversion.aspx

The Chassisworks/VariShock rear system is available with many different options. There are three shock options; single, double, or 4-way adjustable with remote reservoir. The upper and lower shock mounts are available either bolt on, or weld on. You can see that the brackets are laser cut for clean edges and superior fitment and are made from thicker steel than our competitors for excellent strength. You can read a LOT more about this kit by downloading the Product Data Sheet HERE. (https://www.cachassisworks.com/Attachments/DataSheets/5824-XXX_DS_WEB.pdf)

This is the bolt-on version of the lower mount that will work with your stock brackets. Recommended for most applications.
https://static1.pt-content.com/images/pt/2015/01/5824a10_7_-1.jpg

If you get the weld-on lower control arm bracket it gives you an additional lower control arm pickup point so you can adjust the IC. It also opens up additional wheel clearance. The picture below shows the weld-on style bracket. It's the same one we use for our factory welded Chevelle g-Link style FAB9™ housings.
https://static1.pt-content.com/images/pt/2015/01/5824a10_6_-1.jpg

[Gratefuldiver]

Is there a huge difference between coil springs and shocks vs coil overs? What are some pro and cons? Is it silly to run rear coil overs with a traditional set up front?

[eric1967]

I would not be concerned with coil overs. Some of the best money you can spend is a driving school. I will be glad to help you dial your car in. We should hit one of the SCCA test and tunes. Listen to Rod. He know what he is doing. Fresh tires will make a huge difference.

[Carl @ Chassisworks]

Is there a huge difference between coil springs and shocks vs coil overs? What are some pro and cons? Is it silly to run rear coil overs with a traditional set up front?

There are advantages to both. Running different styles front and rear is not necessarily a bad thing. Chris Sr. wrote an article about coilover conversion that covers a lot of ground and common misconceptions. READ IT HERE (http://www.cachassisworks.com/whitepapers/002-CoiloverConversion_WP_WEB.pdf).