Double Venom suspension question

[dvcobra]

I am running bethania garages tubular control arms with carrera coil over shocks up front, pro shock in the rear with springs. I removed front sway bar and changed the rear sway bar to the smaller mustang bar. I love road course racing and am looking for the best handling possible. The car seems to lean too much on the turns and I can't keep up with others on turns.
Should I put the larger CR sway bar back on the rear and are there any other front shocks that are easier to adjust or better? How do I know what setting the carrera shocks are on?
Any other recommendations to get the best handling in the turns?

[Curt C.]

What are your spring rates in the front and rear? Put the front bar back on. In front, I have QA1 coilovers 500lb, Behtania A arms, the CR front bar. In back its 9 inch ford, Bilstein coilovers (250 lb) along with a 1979 4 cylinder sway. I had the larger CR rear sway bar and it was way too much - severe oversteer. Car does well on the road course and keeps up with modern day marques. However, the four link Ford has inherent issues with bind. It would be nice to have a 3 link or torque arm / watts link but this would have to be customized. I know of no CR's with this setup. Before you start spending money, put the front bar back on and see if that helps.

[Double Venom]

dvcobra,
You are running exactly what I ran for auto cross how ever the rear bar is critical but I did REMOVE the front bar. The front bar is the one that is to heavy not the back one. If you have a little ability it is very easy to make a front bar of lighter material. (SPEEDWAY.COM has all the material you need to put one together.) The one I used with the "Double Venom" cars with the Viper engines- over 150 lbs lighter than a Ford BB all dressed.) was a tubular design roughly a 1/2 in diameter.

OK, a few tips I learned at Hondas track; what motor are you running, do you know the weight on the front. What rate springs are you using? Adjusting the fronts- good luck and if you find a better way please let me know!
I ended up taking the front springs apart and putting a thin but even coat of "anti-seize" on the front coil threads. Makes track adjustments much easier!

If you saw the thread about boxing in the rear lower control arms and haven't done it, this is the perfect reason to do so.

Scales? Have you had your car scaled? Very easy, time consuming and critical for auto-crossing, You will or should be able to get a CR cobra right at
48/52% with a driver in the car. Move your battery to the right hand pocket of the trunk. (Please run a long ground '00' from the battery to the motor.) Running the battery ground to the frame, although short run and cheaper it can effect your electrical system, especially if you are running EFI or an MSD
type box.

Carrera shocks have three settings, a stepped tooth design on the housing, we set this tooth to the middle setting.

As Curt C says 250 rates on the rears seem to work ok, but I need to know what weight you are pushing around the track on the front.
Is the front end 'plowing' in the turns or is the rear end too loose?

If you get all this done you may find out that you need a removable front spoiler/air dam to keep the front end down on the straights, as the car will want to go nose light once you get in the 130 mph range or higher. The front air dam should go corner to corner on the car and be no more than 1" off the ground.

A little -fun- type work, another small investment, a little driving time and it will be a long time before anyone in your class passes you on the track!
Keep me posted!
DV

Second time I've tried to edit: Went back and saw what engine you are using-excellent choice! Steering? Manual or power? What rack?

[dvcobra]

DV, here are the answere's to your questions; steering-Flaming River manual steering with your steering column, engine-351W with cast iron heads, front carrera coil overs with 350lb spring rate, rear springs are 200lb with pro shock from Bethania, rear end is a Currie 9" set up for 8.8 suspension components, I run Hoosier road racing radial. I balanced the car and was able to achieve 48/52 & battery is located in trunk on right side.
Handling- the car feels as though it is just leaning too much into a hard fast turn & the tires occasionally rub. As far as plowing or loose rear end, it's hard to say, sometimes it plows and sometimes it feels like the rear is about to slide out.
In conclusion- it sounds like I should change the rear spring rate to 250lb and re-install the larger sway bar in the rear and no sway bar in the front, is this correct? should I do anything to the front end or should this take care of the body roll?
If the rear is too soft, does this cause plowing or loose rear end?
I also have some photo's of the car on the turns showing the body roll if it will help.
Thanks for your quick response and time.

[Double Venom]

DVCobra,
Sounds just like the ones I built! I would go to the 250 on the rear. The rack is perfect. (Power steering does make these cars a llittle twitchy.) I would definately go with at least the stock CR REAR bar. We took the front one off completely until DVII came along and then had the resources and the pros to help us out with the front sway bar. This is where I put one together from "Speedway Motors".

On hard turns your tires should "roll over" about 1/4" onto the sidewalls. Once you get all the minor stuff taken care of it will be time to put your pit crew to work. If you have an area without the cops and the chance of hitting anything, mark of a 100' circle, have a pyrometer handy with probe or even the new heat guns will work. Push the car as hard as you can without spinning out then take four temperatures per tire, side to side and record the numbers. This will tell you if the car needs stiffer weight, looser, air pressure to high/low.
Report back! It's all fun from here out!
DV

[dvcobra]

Thanks again for the help. I am excited to get back to the track and test this out. It' kind of hard to find a place with no cops and no obsticles in Southern Calif.. It might be a while but I will get back to you with the results.

[Curt C.]

Do you want to autro cross or road race? In my opinion, the 350 lb front springs are too soft for road course. They decent for autocross. Removing the front sway bar will lead to more body roll and less understeer. Adding the CR rear bar will result in more oversteer. The two actions combined will cure a sever understeer or lead to greatly increased oversteer. Is your car understeering? I run 500 lb front springs along with the CR supplied bar. Along with the small bar in the rear, car is fairly neutral with no significant roll. This is with a 351W based engine. Car is nearly perfect front to rear weighting and cross weighted. Also, this is a road race setup. I find autocrossing an exercise in frustration.

[dvcobra]

Road racing. I had a professional driver (John Morton) drive my car when I had the CR front and rear sway bars and no coil overs and he said it was way too tight. That is when I started looking at coil overs and other sway bar options.

[Curt C.]

Keep us posted on you results. I would like to further compare notes. What tracks are you running?

[Double Venom]

Curt C.,
You'v'e got some good points but look hard at the stock front sway Bar. This thing was built by Ford for a 4,500 lb car. The actual manufacturers engineers that examined the CR Cobra could not believe that is what we used for the front. I explained back in the original CR days they bought parts that would work off the shelf and never went farther with it.

If you are running good now, and I assume you are I wonder how much better (if any) that you would be with an appropriate bar?
Just some info........
If dvcobra could get us now and after times that would be great!
DV

[Curt C.]

Hey Ed,

No question that the front bar is a little tight. However, I prefer a little understeer as opposed to oversteer, in a Cobra at high speeds. These cars, as you know, with their short wheel bases can be twitchy. Expecially if you get the rear too tight. The CR supplied rear bar is just as fat as the front bar. My car experienced significant oversteer / overcorrection issues with the rear CR bar. I learned that the rear bar should always be smaller than the front. I would love to build an adjustable type Nascar bar like you did. Did that bar utilize splined blades (arms) with adjustable features? Do you still have the drawings? Can you make another? I would love to have one. The circle track stuff is so cheap - I love it.

I have been tracking this car of about 8 years at Spring Mountain, Las Vegas Motor, Willow Spings, Button Willow, etc. The car holds its own with the competition (depending on the driver) - Z06's / Vipers / Lotus, etc. I am convinced that it would run much better with a torque arm / panhard rod set up or a 3 link. Four links with unapparalel bars simply have way too much bind. Since you sold your shop, there is really no one making custom suspension parts specifically for the CR. I do not have the technical expertise to design and build my own and ensure that the geometry is right. The folk that do are quite expensive.

[Curt C.]

Double Post

[Double Venom]

Curt C,
You nailed it, the front and rear bar were splined, changes were quick and relatively simple. Ever hear the saying. "If I had it to do over again!"? I only have a customers car in the shop now (new and grander shop which I really can't take the liberty of using it for a test vehicle. It was so nerve wracking to start with, what, how to mount, where to hook it up and on and on. It turned out so easy though. Maybe I just got lucky, only bent up two wrong bars and mounted the third which I ended up with. "TRC" (Honda of Marysville) tested for us. The G's on a skid pad with their driver out pulled a 1.3 skid pad test (using the exact same configuration as dvcobra with boxed rear control arms). He also burnt up the egine depriving it of oil on the #3 bearing. Viper then told me after I had to buy new parts for this engine that we pulled a 1+ G and knew exactly what bearing went first! Told me I would have to run a baffeled Viper oil pan! Then they tell me...! When I build the next Cobra I plan on building correct bars.

You are right about the size though, we did use the stock bar on the rear but the front was probably half as big in diameter. Thinking back a few years I think Speedway Motors got the weights of the car from me and suggested the size of the bar to start with-?

I love building these cars!
DV

[dvcobra]

Do you have a template or can you make another that fits if I want to test it?

[jdean]

Curt, I do have a 3 link rear suspension on my CR.....similar to what FFR and Hurricane have. I had to fab it myself but it works really well. The mounting point on the chassis is on the passenger side thick angled steel bar that goes vertically from the "shelf" bar to the bottom chassis cross bar. Of course it requires a panhard bar across the rear. I kept the stock CR lower control arms as is, but I will box them like DV says when I have time.

[Double Venom]

jdean,
I was looking at all your pictures. Couldn't find any pictures of your three link.
Any chance of posting some? Why did you change? Did it help? Just seriously interested. Saw your car on the track-definately boxing the rear lowers- you're going to like it!
DV

[jdean]

Here is one....to keep it compact enough to fit in the tight quarters of the CR, I discovered that the Ford Aerostar vans have a 3 link suspension and therefore use a special 8.8 rear end that has the top mounting cast into the side of the pumpkin housing....the rear end does need to have one side shortened since on the Aerostar one side is 3" longer than the other....I fabbed up the control arm myself and welded tabs to the frame member. Works very well, no binding since it is a heim joint, and NO wheel hop on burn outs.

[jdean]

Tough area to try to shoot. Hear you can see where I made the passenger side frame mounting point for the panhard rod....and you can also see the beginning and end of the 3 link control arm at the top.


Maybe this is a better shot....

[Curt C.]

That is great jdean. Where did you get that mount for the differential side of the 3rd link? That is not the upper control arm mount is it? Any pictures of the other side of the panhard bar? What rear spring rates are you running with the setup. This is very exciting to see. Any diagrams or measurments would be most welcomed. Are you running a sway bar?

[jdean]

The differential has the mount cast into the housing. The Aerostar has a 3 link as a stock factory set up.....but the control arm is HUGE....which is why I had to make one. I think the single control arm from the 2007 Mustangs would fit just fine, but those were not out back when I put this together. I will get a pic of the axle mount for the panhard. I dont use a sway bar but I may add one to see what difference it makes, but the car does not lean much as it is now. Springs rates are 275 I think, but dont quote me on it..if so 300 would be better since these have the adjustment screw quite a ways down.