Need a little help figuring something out

[BanditDarble]

I've got WAY more work in mine than just bolting on the pretty parts, that's what makes it so satisfying... Your biggest challenge might be coming up with an appropriate sized front sway bar and making it stock looking. Where you'll run into a challenge I suspect is tire clearance.

Oh I agree. I should have worded that differently. What I meant was I have to modify the stock control arms versus using the pretty DSE or ridetech parts, fab a swaybar versus buying one. Not meant as a dig at all. Wish I could bolt on parts as it would save some time. The parts still need to the proper mounting points which is work whichever way one goes.



The front sway doesn't have to look stock so long as I make it. Won't be too difficult as long as I can get the correct tubing. It's 50 points to change the sway on the front and 20 on the back. I COULD bolt on a Monster bar but they have a clause saying that can penalize above and beyond for parts outside the spirit of the rules. I think a $500 sway would likely get a few value points added so making one is the best option to get a really big bar on the car. The 36MM would be the straight 50 points, same as the fabbed piece. (The rules can be a bit convoluted and subject to interpretation.)

With tire clearance are you talking about with the front control arms? Being a race only car I'm not TOO worried about turning radius. Have actually kicked around going up to 18's to get an even wider contact patch but the tire prices really jump up which could make the tire bills untenable. Clearance on the fenders/quarters is not an issue as I can adjust those. Likely with a baseball bat. Racecar. hah!

[SSLance]

The tire clearance issue is the inside front edge of the tire contacting the sway bar just before full turn left or right. When I ran the 36mm bar, the bar actually rubbed on the frame itself under compression and the tires rubbed the bar on sharp turns. It's more of just a hindrance than a real problem, it never did any damage to my tires, just had to watch for it when pulling back into grid spots or parking spaces at the mall #becausestreetcar ;)

The ridetech MonsterBar solved that with their fabbed steel sway bar links, they clear both the frame and the tires don't touch them.

What will you run for rims? Getting a 9.5" wide rim with the correct 5.0" backspace is tricky in either a 17" or 18" Most likely you'll have to special order them.

[Ron Sutton]

Hey guys,

Considering that Ron's fee is way less than I would be spending for a set of tires for a weekend, less than a pair of 275/40/17 615k's let alone 8, I agree that not tapping his expertise would be foolish. I had actually already visited his site and checked out his prices before posting here.

I asked if Lance's setup Stage 1 setup would be a good baseline for a long course, fairly high speed, setup as it would be easier to replicate with the factory parts that I would have to work with. DSE and ridetech parts are not going to fly in the series I am looking at running, while I am free to change pivot points, springs and such. I can fab up a swaybar out of 1.5" 4130 tube but can't buy a Monster bar for instance. Think along the lines of what Donohue had to work with on his First Gen Trans Am cars. He couldn't open a catalog and get parts. He had to modify the factory parts, make offset bushings, change suspension pivots, cut and weld control arms, etc. That's what I have to do while running on 180tw (615k's are 200tw but the only brand with the size I want.) tires against lightweight E30/E36 BMW's and V6 swapped MR2's with a 3000 pound G body with maybe 250whp.

I should have worded my initial post a bit better, but I'm really curious if one could make this chassis competitive with the parts restrictions. I believe one can but am curious what area one would change on Lance's setup if one was to set it up with no concerns about street drivability and focused only on road course versus autocross. (I have zero interest in autox) And if that change is feasible for a guy with a welder. I'm not looking for specifics.

Can I cut, relocate, weld and drill factory parts and tubing to out corner a 2100 pound BMW E30 in the Carrousel at Road America? The last race there the fast lap was 2:49.

If not I'll build something else. a 2nd Gen would probably be smarter, bigger gas tank and lower CG, but i don't care for the look...

One other thing that hopefully Ron can answer; Are BBSS setups generally easy on tires? These are endurance races, so being easy on tires is important so the tire bill doesn't end up being 3 or 4 grand for a weekend just racing for a trophy.

Lance-Have you ever had a G meter in your car? Obviously it corners hard. I'm just curious if you have measured it.

I've really enoyed this thread, and have picked up from my reading that Ron doesn't like hypotheticals. One has to start somewhere however and figuring out if a car can be made competitive is the logical starting place. I know the chassis can be with loads of parts.

I don't have access to those parts however due to the class rules.

edit-Lance-Road America would be the focus of the car, however I would likely run it at a few other tracks. Brainerd and possibly Autobahn Auto Club would be likely as would Daytona if I can get a 5.3 in the car while staying under the point limit. A guy HAS to race at Daytona if he gets the chance. btw-While a number of Chump cars look like rolling wrecks, more and more do not and this one definitely would not. Whatever I build will definitely look like a racecar and will perform like one. Just lacking the big horsepower and name brand aftermarket parts.

Even at that, at the last Chump race at Road America a 79 Camaro had the top speed in the speed trap at 127mph, so a good Chump is not terribly slow. I've seen claims of 140+ at Daytona with GPS verifying.

Thanks,
Joe

Hey Joe,

I understood your post. Sorry mine wasn't clear. You may be looking to see if Lance's set-up is right for your goals, which I don't think it is. The answer is 2-part.
1. Yes, the type of mods Lance made ... is good route for your Chump Car G-body for road racing.
2. The exact changes, roll centers, geometry, etc ... will likely be different.

You can make your car a mean road course machine within the Chump Car rules. The keys are:
A. Deciding on a suspension strategy (hi travel/low roll, low travel/high roll or moderate travel & roll)
B. Work out the spring & sway bar rates to achieve the strategy
C. Correct & optimize the geometry for the strategy.

* I just wouldn't copy Lance's work or numbers, as your car could be ... and should be ... set-up differently to achieve optimum road course performance. you don't have the same goals Lance has with his air conditioned, big gulp in the cup holder, comfy GTO seated, wife on the passenger side, Sonic drive in cruising, corn dog driver eating street machine that happens to win CAM class SCCA autocross events.

I made up the part about the corn dog.

[BanditDarble]

Lance-Torque thrust II's are available 9.5" wide with a 5.5 backspace on the 17's and 5.75 bs on 18's. Should be workable unless they hit the tie rods? Can use spacer but would like to avoid due to scrub and bearing stress. Was initially looking at 17x9 Soft 8's with a 5" bs until I saw they weigh 40 pounds each. Too much unsprung mass and even with C5 brakes would make things more difficult.

Haven't looked into wheels quite as much as I'd like. Would like to avoid custom or high end due to price and likelihood of damage.

Hi Ron. I'm liking the sounds of BBSS however I am curious which is better for tire wear? This is "fun" endurance racing that can be admittedly expensive. The races at Road America are Double 7's, meaning 7 hours Saturday and 7 hours Sunday. Daytona is a 14 hour race. I'd prefer to keep the tire costs down as much as possible and hopefully have a car that is "easier" to drive for complete rookies. Is one style of suspension setup inherently better than the other when it comes to tire wear or are they about the same assuming a good setup? Most teams are not having to change tires but they are lighter with less power.

I do like the G body for various reasons but let me ask you this; Which would you build? Second gen F body, 75-79 X body (Nova has second gen suspension I gather), or 78-88 G body?

I've always avoided leaf springs but as I gather the F body front suspension is much better than the G. The X is obviously lighter.

While the discussion has been about G body suspension setup I am not set on the car. It is just my personal preference when it comes to appearance. If a F or X would easily be better on a road course with similar effort I may go that way.

Thanks your help here. Your threads here and at lat g have really peaked my interest in doing this.

[SSLance]

Lance-Torque thrust II's are available 9.5" wide with a 5.5 backspace on the 17's and 5.75 bs on 18's. Should be workable unless they hit the tie rods? Can use spacer but would like to avoid due to scrub and bearing stress. Was initially looking at 17x9 Soft 8's with a 5" bs until I saw they weigh 40 pounds each. Too much unsprung mass and even with C5 brakes would make things more difficult.

Haven't looked into wheels quite as much as I'd like. Would like to avoid custom or high end due to price and likelihood of damage.

You will have more trouble on the back than on the front with a 5.5" BS, I run a 1/8" spacer with my 5" BS wheels and can barely fit my finger between the frame rail and the rim in the back. A frame notch would make more room back there, but that causes a whole nuther host of issues. On the front as long as you don't mind a reduced turning circle, they might be okay. Some inner fender clearancing may be needed but again, it's a race car so that's okay. The GTA wheels in a 16x8 are a good size for a cheap factory light wheel, but they aren't quite as wide and good sticky street tires in a 16 are very hard to come by. It might make more sense to pick up a nicer couple of sets of rims to ease on the tire budget down the road. Some people have the CCX BMW wheels re-hooped as an option you might consider as well.

[Rod]

his air conditioned, big gulp in the cup holder, comfy GTO seated, wife on the passenger side, Sonic drive in cruising, corn dog driver eating street machine that happens to win CAM class SCCA autocross events.

I made up the part about the corn dog.

[SSLance]

Do NOT encourage him Rodney!! And besides...I sold the GTO seats...

[BanditDarble]

You will have more trouble on the back than on the front with a 5.5" BS, I run a 1/8" spacer with my 5" BS wheels and can barely fit my finger between the frame rail and the rim in the back. A frame notch would make more room back there, but that causes a whole nuther host of issues. On the front as long as you don't mind a reduced turning circle, they might be okay. Some inner fender clearancing may be needed but again, it's a race car so that's okay. The GTA wheels in a 16x8 are a good size for a cheap factory light wheel, but they aren't quite as wide and good sticky street tires in a 16 are very hard to come by. It might make more sense to pick up a nicer couple of sets of rims to ease on the tire budget down the road. Some people have the CCX BMW wheels re-hooped as an option you might consider as well.

Thanks for the info Lance.

Notching the rear shouldn't be a big deal as the body will be off the frame and I will be able to add some reinforcement. Plus the cage will stiffen things up as well. Another option would be swapping in a 71-72 A body rear which is 2.5 inches wider while also giving me a stronger axle. Points for that however and the wider axle would likely make suspension tuning more difficult as the rear would have more bite.

I came across the BMW wheels thing the other day and it might be something to look into. Stock the offsets are way off of course, but if a guy could pick some used/take offs cheap enough rehooping might be an option. Unfortunately for us none of the later Camaro or Vette wheels work on a G body while the guys racing BMW's have piles of 16 and 17 inch used wheels available for cheap. Oh well, it is what it is.

The GTA wheels won't clear the C5 brakes so they would be a no go.

It's all the little things... heh

[Ron Sutton]

Hi Ron. I'm liking the sounds of BBSS however I am curious which is better for tire wear? This is "fun" endurance racing that can be admittedly expensive. The races at Road America are Double 7's, meaning 7 hours Saturday and 7 hours Sunday. Daytona is a 14 hour race. I'd prefer to keep the tire costs down as much as possible and hopefully have a car that is "easier" to drive for complete rookies. Is one style of suspension setup inherently better than the other when it comes to tire wear or are they about the same assuming a good setup? Most teams are not having to change tires but they are lighter with less power.

I do like the G body for various reasons but let me ask you this; Which would you build? Second gen F body, 75-79 X body (Nova has second gen suspension I gather), or 78-88 G body?

I've always avoided leaf springs but as I gather the F body front suspension is much better than the G. The X is obviously lighter.

While the discussion has been about G body suspension setup I am not set on the car. It is just my personal preference when it comes to appearance. If a F or X would easily be better on a road course with similar effort I may go that way.

Thanks your help here. Your threads here and at lat g have really peaked my interest in doing this.

The low roll strategy is what we often refer to in racing as a "long run" set-up. The downside is it takes about 1 to 1.5 laps for the tires to be 100% hot. But then the tires & car perform the same lap after lap until the tires wear out the tread. A high roll set-up's advantage is the tires come in quicker ... usually within 1/2 lap or less ... but overheat and the handling "goes away" quicker. Low roll spreads the loading over the tires more evenly ... and promotes longer wear. High roll over works the outsides tires in each corner, making them hot, and wears them out sooner.

I think you should build the car you'll enjoy the most. If we were all looking for the optimum performance, we wouldn't be be building 60's-80's muscle cars. If your love for each body style was equal, the Gen 2 F-bodies have a better front suspension, brakes & aero shape.

Best wishes ... but mostly ... have fun.

[UMI Tech]

Hey Ron.

Would we ever want to adjust anti-dive on the upper a-arm or perform any other magic up there? I realize there isn't much room to work with but if it would be beneficial...

I'm envisioning our local street stock divisions where that type of adjustment is common.

[Ron Sutton]

Hey Ron.

Would we ever want to adjust anti-dive on the upper a-arm or perform any other magic up there? I realize there isn't much room to work with but if it would be beneficial...

I'm envisioning our local street stock divisions where that type of adjustment is common.

Hey Ramey!

As you know, the anti-dive percentage is a measure of the mechanical leverage the control arm assembly has over the spring under braking. Through testing, I've been all over the place with both anti-dive & pro-dive. For those reading along with us that don't know what they do ... anti-dive makes the spring act stiffer under braking & pro-dive makes the spring act softer under braking. If a car had zero anti-dive, the front end dive (compression) under braking would be solely based on spring rate & shock valving. By running anti-dive in the front control arms, we're making the car dive slower, and therefore less.

For those that don't know this, in addition to being a savvy suspension engineer, Ramey was crew chief in oval track racing.

Also as you know Ramey, in oval track, racers play with different anti-dive percentages ... and even pro-dive ... side to side. I've seen (and tested) running moderate anti-dive on the RF (say 40-50%) & small amounts of pro-dive (10%-20%) on the LF ... to get the front end to dive & stay flatter on corner entry under braking (oval track - turning left). The only thing I don't like about running pro-dive in those situations is we have caster loss on the LF ... which is the opposite of the goal. So after tons of testing, I landed on running small amounts of anti-dive on the LF (20% +/-) and more on the RF (40-50%) ... and of course run a LOT of spring split. (Spring split means we're running different spring rates left & right.) So instead of running springs of 325#/375# L/R with pro-dive on the left & anti-dive on the right ... I preferred 250#/375# L/R ... with a small amount of ant-dive on the left for caster gain. Of course other crew chiefs that also won races ran pro-dive successfully, but with more KPI split in the spindles. There's a lot of different ways tot skin that cat.

For road course track days, autocross & overall performance street performance, we obviously want everything to match side-to-side. We want the same spindle KPI, same anti-dive, same caster & camber. So the only question is how much anti-dive. I know autocross & road racers that run stiff front springs are all over the map ... from 20% to 70% ... depending on their theory. Personally, I like my high travel cars to run moderate anti-dive, typically around 40%, and soft enough front springs to hit my travel target under braking. This makes the springs act softer when not under braking ... which provides several benefits ... smoother ride, less harshness, etc ... but mainly more grip.

A key thing is that the anti-dive be the same on the left & right. I just did the calcs on a SCCA racer with a 3rd gen Camaro ... and the anti-dive was dramatically different side to side. It was 20% on LF side & 41% on the RF side. It came from GM that way. Typical production tolerance variances. That creates more diagonal roll on RH corners ... making the car looser ... and less diagonal roll on LH corners ... making the car tighter. Gotta fix that.

While I am a fan of guys testing to learn what stuff does on practice days & track tests ... I'm not a fan of using anti-dive as a "tuning tool" at race events. Some guys do tune with anti-dive to fine tune their spring rate ... if they need the front end to dive quicker or slower. I prefer to change shock valving to achieve that. In summary, if someone's anti-dive is different from side to side ... fix it for Pete's sake. If your anti-dive is too low ... under 30% ... I suggest increasing it to 40-50%. If it is too high ... over 55% ... and the car isn't "getting on the nose" hard enough ... I'd decrease it into the 40-50% range.

[RMMiller]

Well you guys ate up the better part of my weekend reading this thread! Ron, you're generous with your knowledge, thank you for that. I feel like I understand the suspension and how the angles change the way it all works much better now, not that I can do anything with it at the moment. Again, thanks for sharing the knowledge Ron and thanks to Lance for taking us along for the ride.

[Ron Sutton]

Well you guys ate up the better part of my weekend reading this thread! Ron, you're generous with your knowledge, thank you for that. I feel like I understand the suspension and how the angles change the way it all works much better now, not that I can do anything with it at the moment. Again, thanks for sharing the knowledge Ron and thanks to Lance for taking us along for the ride.

You're welcome Mr Miller. Lance's goal was to make his car handle better ... which was my goal for him. Our other goal was to show the why & how to getting the suspension geometry matched side to side & optimized for an individual's suspension strategy.

We didn't throw a bunch of parts at the car. We focused on getting the geometry optimized and the front/rear spring & bar rates balanced for a neutral handling car.

Best wishes with your car.

[Ron Sutton]

Hey Folks,

I have a lot to wrap up for my 2015 Workshop & Book Tour (details HERE) ... so I won't be answering questions on this thread until mid-summer.

Best wishes!

[GrabberGT]

Studying up a little before this Thursdays workshop. Im up to page 10 in this novela and have already learned a ton.

[Boss002]

This is being done way later than I had hoped to have done this, and on a iPad of all things, but wanted to give some feelings on Lance Hamiltion's Ron Sutton setup SS Monte Carlo "Barney"

I will start off by saying I have driven over 35 different cars in autocross, I've won nationals pro solo, match tour, and champ tour, but never the national championship, and this is only the second vehicle that was a frame instead of unibody, the other one being a late 70's ford pick up with a big block powered by propane.

I prefer racing on R comps, but have had my fair share of time on street tires and even some stock cars. The newer tires are starting to bridge the gap between street 200 two and r comps. The reason I'm mentioning tires first is because I feel the biggest thing holding Barney back from being faster are the falken tires. I know the sponsor a lot of stuff , I know they are the only wide tires below 18", I know they are cheaper, but if you really want to compete , car needs some 18" wheels and Bridgestone RE-71R or BFG rival S (still haven't driven on these yet). /end tire rant.

As for the car itself. It drove down the road like a dream, I love that it has a 6 speed, it looks amazing, has great tq and is a great balance of road tripper, show car, and race car. The softer spring rates helped the car from being skippy or darty on rough surfaces, and the car never felt like it would snap ones sending it into a slide. At first autocross run I was originally feeling the car would be "too soft" but was quickly surprised by how the car responsed through the slalom, it had roll but it still did exactly what I wanted and without drama.

The only maybe issue other than tires I had was we need to adjust the shocks a little to help on throttle off rotation, and I feel the rear diff might be too aggressive on its lock up giving the car some in need sliding where I should just smoothly go around.

Other than that Barney was great! I want to thank lance again for letting me borrow the car for the cam challenge, and thank Ron Sutton for helping with the setup and opening my eyes on making the big girl handle.

[Ron Sutton]

Hey Everyone ! I've caught up enough ... so now I back answering questions on my Suspension, Safety & Aero threads.

So if you have questions ... post'em up!

[rq375]

Thanks to everyone who has contributed to this thread, especially Ron and Lance. I am also working on an 85 SS with very similar goals and this has saved my quite a bit of money and guesswork.

Given properly squared up chassis points as described above, any thoughts on a longer lower control arm to improve scrub while also moving the ball joint forward to improve caster? (I'm building arms and can jig up alternative dimensions) I'm also thinking of cutting the outer spring pocket bulge off the frame and plating it back flat to use a conventional upper coil over mount and to get the lower mount out closer to the ball joint for more shock travel.

thanks

[Ron Sutton]

Thanks to everyone who has contributed to this thread, especially Ron and Lance. I am also working on an 85 SS with very similar goals and this has saved my quite a bit of money and guesswork.

Given properly squared up chassis points as described above, any thoughts on a longer lower control arm to improve scrub while also moving the ball joint forward to improve caster? (I'm building arms and can jig up alternative dimensions) I'm also thinking of cutting the outer spring pocket bulge off the frame and plating it back flat to use a conventional upper coil over mount and to get the lower mount out closer to the ball joint for more shock travel.

thanks

Sure, we do it all the time. It just requires deeper backspaced wheels & making sure there are no issues from that.

Same on the shock travel. Any time we're modifying control arms, we typically ...
* Move the lower shock mount out to improve shock responsiveness
* Move the LBJ forward to increase caster

In Lance's case, we used off the shelf ridetech arms & did not modify them. I have a new line of control arms being designed currently ... that ridetech is building for me ... that does these exact things (moves the lower shock mount out & ball joints for more caster) as well as cut & weld in upper shock mount. They also use screw in ball joints which provides me with more geometry & spindle options. These will be sold only through RSRT, not Ridetech.


You're on the correct path. Best wishes!

[Rat Stu]

In Lance's case, we used off the shelf ridetech arms & did not modify them. I have a new line of control arms being designed currently ... that ridetech is building for me ... that does these exact things (moves the lower shock mount out & ball joints for more caster) as well as cut & weld in upper shock mount. They also use screw in ball joints which provides me with more geometry & spindle options. These will be sold only through RSRT, not Ridetech.

Ron,
Another huge thank you for all of your time, effort and good will providing the wealth of knowledge in this thread.

My car is a 1960 Studebaker with a 79 malibu front clip. I just took it to my first track day ever last week. All the drivers were newbies so it is hard to judge my car's abilities but I was in the middle of the pack not far behind the camaros and vettes. I was very pleased since this is a budget build that I did myself while learning to weld and building my first motor.

Its not a dedicated track or AutoX car. I like driving it on the street..when I don't have it torn apart. So should I be shooting for similar caster numbers to Lance? I can currently get about 4.75 degrees while keeping the camber correct. I plan to align the LCA mounting holes this winter and I am wondering if I should move the lower bj forward at the same time. If the holes are close I may just use some of these new arms you are talking about.

Up front the car has inexpensive circle track tubular UCAs, 1/2 inch tall ball joints top and bottom, stock LCAs, QA1 single adjustable coilovers with 500# springs and a 7/8" rollbar. The camber curve may be too aggressive as I lowered the LCA mounting holes 1/2" also. The car weighs 3200# with me in it and the 400hp sbc. The rear is a Monte 7.5 inch unit that I mounted to the Studes leaf springs and non-adjustable shocks. I also added a track bar to keep the wheels from hitting the fenders.

I am also debating whether or not to buy the Performance Trends software to dig a bit deeper. I did allot of work on a RC calculator spreadsheet that I put together last winter but without having any end goals I found I was just obsessing over the numbers and never getting out to work on the car.

Thanks Again,
Greg