1st autocross run.

-
7

70b7duster

Well-Known Member
Joined
Feb 8, 2014
Messages
60
Reaction score
2
Location
San Jose
So I signed up and ran as a guest in my first autocross event today. Found some things that need improving and would like some advice.

Quick rundown on my car. 70 duster, 360, reverse manual 727, 8 3/4 posi 3.55, HDK front w/ QA1 double adjustable shocks 500# springs, superstock 2800 springs w/ hotchkis/fox shocks, 1" lowering front spring mout, 275/40zr 18 rears, 245/40zr18 fronts, Goodyear asymetrical f1 tires. 13" cobra front brakes. 11.7" cobra rear brakes.

Had a little push, and a decent amount of roll in the front, the guys at the event suggested to get a bigger sway bar rather than messing w/ spring rates. Thoughts? Would using the adjustment in the shocks make much of adifference? The rear handled pretty well. But can see that the rear was moving side to side (could see marks from the spring touching the tti exhaust at the rear of the car). Anyone run or have advice on a pan hard bar? Any other input from personal experience would be great.
 
If you're not running sway bars right now, I would start with there. If you are, what sizes are on there right now? Adjusting the shocks isn't really going to effectively control your body roll, and if you go overdamped on the shocks you'll just end up with a harsh ride.

Do you know what the actual wheel rate works out to be for the 500# springs? Maybe Denny will chime in. You might also ask wracks71 what he's running for spring rates on the AlterKation set up he has on his car, he spends a good amount of time on the track. I'm running a 300 lb/in wheel rate with my 1.12" torsion bars on my Duster, and I still run a Hellwig 1.125" front bar. I haven't run the car at an autoX yet but I'm pretty happy with the handling so far.

As far as movement in the rear, that may have a little to do with the arch on the SS springs. While the lowering hanger may take care of the ride height, the more arch the spring has at ride height the more side to side movement there's going to be. Ideally the springs should sit fairly close to zero arch at ride height, as that helps to limit the side to side motion. Obviously it won't get rid of it entirely, but it does help. Also, are you running left/right SS springs or two of the same? If you're running the SS springs as intended with the left/right springs the difference in arches and spring rates from left to right will not help your cause on an autoX course. If you're looking to spend a lot of time on the autoX course I would do something different for rear springs before I went to a panhard bar.
 
^^^^Like he said
SS springs are designed for a car going down a drag strip. You might wanna consider changing the springs to one designed for handling. Hotckis sells a pair (as do others but they are the only ones coming to my mind at the moment).
 
attachment.php


Not sure if you're still at this ride height, but that's too much altitude in the rear, and far too much arch on the rear springs for autoX. You shouldn't be able to see your leaf springs hanging down below the body of the car, and ideally your car should sit dead level. Not the best "look" for a musclecar, but the less rake you run the better you'll handle.

I'm running AFCO 20231M leaf springs. They have a reinforced front section (similar to other performance springs), but they sit with almost zero arch in the back. That really limits the side to side travel. And, lowering the tail end will change your wheel weights up front, so that should help with the front body roll as well. I know there have been a few folks with Dusters that had issues with the Hotchkis springs, not sure if they've addressed them or not.

The 20231M's are 121lb springs, but I run them with a E-body rear sway bar, which is 7/8". I still have it adjusted to the lightest setting of 3, seems pretty decent at least out on the country roads. I'm pretty happy with what I've got, but I'm sure I still have a decent amount of tuning to do once I finally get to a track. Next spring rate up is the 20231 at 142 lbs, but I think that's going to be too much for an A-body with a sway bar.
 
Thanks for the replies! If I remember correctly the front bar is 1". The rear springs are matched. I already had the springs, and the thought after speaking to a few people was rather than buy springs and a rear sway bar, control the rear roll with spring rate. Which seemed to work quite well just had some side to side movement like you mentioned was probably due to the arch. I raised the nose about an inch from that picture. Here's my idea for the rear. Let me here some feedback.

Rather than dumping a bunch of money into springs and bars. (When I eventually want to do a HKD triangulated 4bar ;). Use afco spring sliders to get the rear down, and also help w/ the side to side movement, fab a panhard bar, and maybe put a 1" lowering block in it.
 
70b7duster said:
Thanks for the replies! If I remember correctly the front bar is 1". The rear springs are matched. I already had the springs, and the thought after speaking to a few people was rather than buy springs and a rear sway bar, control the rear roll with spring rate. Which seemed to work quite well just had some side to side movement like you mentioned was probably due to the arch. I raised the nose about an inch from that picture. Here's my idea for the rear. Let me here some feedback.

Rather than dumping a bunch of money into springs and bars. (When I eventually want to do a HKD triangulated 4bar ;). Use afco spring sliders to get the rear down, and also help w/ the side to side movement, fab a panhard bar, and maybe put a 1" lowering block in it.
Click to expand...

the rear shackle deflect big time. i installed sliders in my car and i have nearly zero side to side movement.

 
I've read that the proper way to install them is to have it 2/3 to the rear of the slider with the weight of the car on it. Is that how you welded yours in younggun2.0?
 
Well I have mono leaf springs so I went pretty close to middle. I think 2/3 back with ur spring is safe bet
 
70b7duster said:
Thanks for the replies! If I remember correctly the front bar is 1". The rear springs are matched. I already had the springs, and the thought after speaking to a few people was rather than buy springs and a rear sway bar, control the rear roll with spring rate. Which seemed to work quite well just had some side to side movement like you mentioned was probably due to the arch. I raised the nose about an inch from that picture. Here's my idea for the rear. Let me here some feedback.

Rather than dumping a bunch of money into springs and bars. (When I eventually want to do a HKD triangulated 4bar ;). Use afco spring sliders to get the rear down, and also help w/ the side to side movement, fab a panhard bar, and maybe put a 1" lowering block in it.
Click to expand...

Sounds like a plan to me. I don't think you'll need a 1" lowering block with the sliders. You can see in younggun's picture that just installing the sliders will lower the car. If you're springs aren't relocated like his are, I would weld an "L" shaped piece of channel to the top of the slider so that you can use the stock rear spring mount. Put the slider flush with the bottom of the frame at that mount, and locate the "L" bracket so that you can use the original shackle mount bolts. Or just weld the slider onto the bottom of the frame there below the original shackle mount, depending on whether or not you care if the slider bracket is still there after you convert over to the triangulated 4-link.

Looking at younggun's picture that would put the slider even higher than his, and would probably work out to at least an 1" of drop, if not more.

lilcuda said:
Where was the autocross? I've been looking for a place to try autocrossing my car.
Click to expand...

I'd be interested in the answer to that too. In fact, if you let me know when the next time you're planning on taking your car out I'd love to try and make it down. I'm just up in Sacramento. I've yet to get mine on any kind of course, and I'd love to see a HDK car in action.
 
this is the club. http://www.lmsportscarclub.org/ they run the third sunday of every month.
I heard about it from a co-worker whose friend is a member. I signed up as a guest. it only cost $25 for 4, 2 lap runs. i grew up racing quarter midgets, micros, and midgets. so it was a lot of fun to be able to do something similar to that again. it would be awesome to have some more mopars out there(as i was obviously the only one).

so for the next meet i will hopefully have it converted to a power rack (that was a workout lol), give it two more clicks for compression, get the sliders installed, and maybe fab up a panhard bar. getting the rear down i think will help a lot w/ the roll in the front.
 
70b7duster said:
this is the club. http://www.lmsportscarclub.org/ they run the third sunday of every month.
I heard about it from a co-worker whose friend is a member. I signed up as a guest. it only cost $25 for 4, 2 lap runs. i grew up racing quarter midgets, micros, and midgets. so it was a lot of fun to be able to do something similar to that again. it would be awesome to have some more mopars out there(as i was obviously the only one).

so for the next meet i will hopefully have it converted to a power rack (that was a workout lol), give it two more clicks for compression, get the sliders installed, and maybe fab up a panhard bar. getting the rear down i think will help a lot w/ the roll in the front.
Click to expand...

Ahhh. Lockheed Martin. I think they discourage guests from coming on a regular basis. As I understand it, you have to be an employee or retiree from LM in order to join. I knew a guy who worked there. Not sure if he still does. I lost touch with him. He was a good driver.

I was hoping for a regular thing I could go to.
 
I was one of 4 people that didn't personally know anyone and were 1st timers so I guess it would be worth a shot. Was also told to come back. Where are you located lilcuda?
 
70b7duster said:
I was one of 4 people that didn't personally know anyone and were 1st timers so I guess it would be worth a shot. Was also told to come back. Where are you located lilcuda?
Click to expand...

Interesting. Maybe their turnout is low, so they are opening it up to others?

I'm in San Jose.
 
A panhard bar would locate the axle effectively. However, it will make the car behave differently in left and right turns because it attaches to the axle at one end. IMO, a Watts link works better because it attaches at the center of the axle and has equal effect at either end. The problem is going to be mounting one on an 8.75" axle housing. Another problem is going to be sure that it does not interfere with your tail pipes and rear anti-roll bar (if any).

I ran one of these on a NASCAR Sportsman short track car back in the day. We quit chewing up the inside of RH tires and the practice was banned the following season.
 

Attachments

  • 1940-willys-pickup-watts-linkage-build.jpg
    45.7 KB · Views: 1,064
Lilcuda I believe there was 20 or so cars Sunday. I asked about becoming a member and they said to show up as a guest a few times before I can become a member.

2 darts, I know a watts link is superior to the panhard bar, but like you said I dont think its doable w/o chopping up the $800 dollar tti exhaust.
 
Be careful mounting the slider so far up in the car. You don't wanna disturb geometry too much. The front spring eye in my car is nearly 3" up from stock also. I know moving the front spring eye up helps with traction and handling.
 
If you are moving the front eye and rear mount up or down. you gotta recheck your pinion angle. If you don't move the front and rear the same, you WILL have a pinion angle change.

Might have been off before and the change makes it better. Or vice versa. But just gotta check at least.
 
70b7duster said:
So I signed up and ran as a guest in my first autocross event today. Found some things that need improving and would like some advice.

Quick rundown on my car. 70 duster, 360, reverse manual 727, 8 3/4 posi 3.55, HDK front w/ QA1 double adjustable shocks 500# springs, superstock 2800 springs w/ hotchkis/fox shocks, 1" lowering front spring mout, 275/40zr 18 rears, 245/40zr18 fronts, Goodyear asymetrical f1 tires. 13" cobra front brakes. 11.7" cobra rear brakes.

Had a little push, and a decent amount of roll in the front, the guys at the event suggested to get a bigger sway bar rather than messing w/ spring rates. Thoughts? Would using the adjustment in the shocks make much of adifference? The rear handled pretty well. But can see that the rear was moving side to side (could see marks from the spring touching the tti exhaust at the rear of the car). Anyone run or have advice on a pan hard bar? Any other input from personal experience would be great.
Click to expand...

Like it was said, we need to know the wheel rates.

But 500 lbs springs seem a little soft for what you are trying to do. BUT can't say anything for sure without wheel rates.
 
look at the post though, it was made in 2007. come out to the next one and check it out. I can give you the email of the guy I got in touch w/ to get on the guest list if you'd like.
 
70b7duster said:
look at the post though, it was made in 2007. come out to the next one and check it out. I can give you the email of the guy I got in touch w/ to get on the guest list if you'd like.
Click to expand...

Sounds good. Send me a PM with his email address.

Thanks!
Lee
 
70b7duster,
What other kinds of cars were at the AutoX? Was this a mopar only, or was there a variety of cars?

My wife was a member of a Nissan/Datsun club which hosted an went to several events. She runs a modified 72 Datsun 510 which has 1.5 inch front sway an 1 inch rear. Then runs a softer coil spring rate. An even still when she would push it hard could lift a rear tire off the ground. This combination allowed there to be some general suspension for road manors an the ability to corner. All in all it has been a good package.

Keep in mind that the 510 is a factory coil suspension car, an this one has been heavily modified.

My opinion, if I was going to autox a mopar of this era, I would be planning on a double triangulated 4 link rear such as seen on Jeeps an buggys.

John
 
ohh man, im in gilroy, i want in on some of this action!!, OP, lets hook up some time. I have an RMS front end on my 68 cuda I'm building. maybe we can help each other out!
 
You must log in or register to reply here.
-

Back
Top