Ideal front and rear suspension setup

boxhead · #1 (**permalink**) 10-06-2010, 03:03 AM

If you where building a Cobra purely for circuit racing with the occasional drag weekend thrown in, what design would you use?

Front end I guess idealy would be uneven length upper and lower control arms, with front and rear upper and lower rose joint inner control arm mounts, U shapped arms (so no caster bar is required)?
Is there a site somewhere that allows you to play with designs so you can see what camber/caster changes occure with suspension travel?

For rear end, would IRS be best or a watts link type setup on a solid axle?

Thanks for any links or ideas.

xlr8tr · #2 (**permalink**) 10-29-2010, 04:01 PM

check out the JBL cobra- looks like the best suspension setup I've seen on any cobra.

http://www.jblmotor.com/car1.htm

Note they have a new rear fender thats much closer to original look, no pictures on the website though.

john chesnut · #3 (**permalink**) 10-29-2010, 04:39 PM

I'll stick with my new Corvette aluminum double wishbone independent front and rear set up. I use their aluminum differential as well which I converted into taking a driveshaft. It bolts into my backbone trans tunnel. With an aluminum V8 and Tremec 6 speed the performance is quite spectacular. I think it's a good compromise to run on the Street, Roadcourse, and occasional Drag. I'm sure other designs work great as well. But, I am partial to mine. Have fun, john

xlr8tr · #4 (**permalink**) 10-30-2010, 06:36 PM

Hey John, I didnt know you were building the cobra's again- I saw the speedster (looks awesome!!)

Cheers,

boxhead · #5 (**permalink**) 10-30-2010, 07:02 PM

Mark, the JBL stuff looks interesting, but how has it proven to be in actual track conditions?

John, thanks for the idea of Corvette stuff, is it all adjustable? I would assume so.

I have been reading this site http://www.gmecca.com/byorc/designstrategies.html and will be buying some software I think.

john chesnut · #6 (**permalink**) 10-30-2010, 07:19 PM

Thanks for the positive comments Mark. After taking a year off I decided to offer my Speedster as a kit. So, I advertised it in Kit Car Builder. But, I informed them a few weeks ago that I am not going to build any more kits to sell. I love the cars and I am going to drive the heck out of mine. I never built them to make a living and now it is time to realize that I need to slow down and enjoy life. Hopefully I can find someone to take over my projects and market them. I have the C5 based Speedster and C5 based Cobra jigs and copy frames for both along with bodies to pull molds from. If anyone is interested just PM me.

vector1 · #7 (**permalink**) 10-30-2010, 07:22 PM

i used to have an '02 zo6 and now have the jbl, the jbl will run circles around the zo6. the zo6 because of the rear transverse leaf spring handled funny imo. the rear would take a set and then take a small hop or skip because of the rear spring unloading some of the weight transfer, i think that is the way to describe it. some use a coilover setup on the zo6 which might alleviate this.

john chesnut · #8 (**permalink**) 10-30-2010, 10:11 PM

I converted the rear to coil overs. I have experienced the snap oversteer associated with the transverse spring. (Much worse in the C4 than the C5) The rear in my car is planted, smooth and very predictable. No nasty habits. I have always admired the JBL frame and suspension. I have never driven one but it would be high on my list I am sure that it works great. The C5 parts were easy to get, pretty cheap, and I am familiar with them as I have used them in my other cars. I'm pretty sure that my Cobra will run rings around a Z06 as well.

GMS · #9 (**permalink**) 10-31-2010, 07:41 AM

Photo comparison of old JBL and new JBL body.

Larry

vector1 · #10 (**permalink**) 10-31-2010, 08:10 AM

Quote:

Originally Posted by GMS

Photo comparison of old JBL and new JBL body.

Larry

larry, you need to get a pic of the rear of the jbl against an "original" style and show the difference in the width and height. pretty dramatic. even though the jbl is set at the same ride height as an "original" it appears lower. the width will scare anyone with the 335 tires.

xlr8tr · #11 (**permalink**) 11-02-2010, 06:04 PM

Quote:

Originally Posted by vector1

larry, you need to get a pic of the rear of the jbl against an "original" style and show the difference in the width and height. pretty dramatic. even though the jbl is set at the same ride height as an "original" it appears lower. the width will scare anyone with the 335 tires.

I'd like to see that! I bought a used Can-Am cobra recently, (time, money and circumstances dictated doing that or I'd never get into this hobby the way I want to) but honestly my heart is still set on a JBL. One day, hopefully sooner rather than later!!

vector1 · #12 (**permalink**) 11-02-2010, 07:13 PM

the car closest should appear largest.....

3rd car from the right in this pic

i'll see if i can find a pic from the rear.

Mac VABCH · #13 (**permalink**) 11-02-2010, 07:40 PM

Boxhead,

www.corner-carvers.com is an excellent site for Tech questions like that. But be very careful and read the forum rules. If you just ask a question that could easily have been answer by searching on there site and google they will be rude. They pride themselves as being a more of a tech site that a social site... Also as a new user you must read and heed the forum rule until you are approved. Its a pain in the ass but they have there reasons and its there site. When I can't figure something out thats where I go. Mac

xlr8tr · #14 (**permalink**) 11-03-2010, 04:20 PM

In the side shot, you can really see the height difference in the rear quarter area above the rear wheels.

Quote:

Originally Posted by vector1

the car closest should appear largest.....

3rd car from the right in this pic

i'll see if i can find a pic from the rear.

vector1 · #15 (**permalink**) 11-04-2010, 04:05 AM

Quote:

Originally Posted by xlr8tr

I'd like to see that! I bought a used Can-Am cobra recently, (time, money and circumstances dictated doing that or I'd never get into this hobby the way I want to) but honestly my heart is still set on a JBL. One day, hopefully sooner rather than later!!

i'm curious, what is a "can-am" cobra?

boxhead · #16 (**permalink**) 11-04-2010, 05:18 AM

Quote:

Originally Posted by Mac VABCH

Boxhead,

www.corner-carvers.com is an excellent site for Tech questions like that. But be very careful and read the forum rules. If you just ask a question that could easily have been answer by searching on there site and google they will be rude. They pride themselves as being a more of a tech site that a social site... Also as a new user you must read and heed the forum rule until you are approved. Its a pain in the ass but they have there reasons and its there site. When I can't figure something out thats where I go. Mac

Thanks for that Mac, I will check it out and read what I can before I fire any questions about.

Mac VABCH · #17 (**permalink**) 11-04-2010, 06:18 AM

Box Head,

The Rules for new users are located General Discussion Forum. Read all the sticky threads at the top. The Honor List is not required reading but puts things in perspective for me.

boxhead · #18 (**permalink**) 11-04-2010, 07:20 AM

Hooley Dooley, I just registered and started doing some reading, they do run the place how they want it.

But if has the info I need then all will be good

Mac VABCH · #19 (**permalink**) 11-04-2010, 07:50 AM

They have some NASCAR engineers and many SCCA racer. Many are just self taught, but they are "difficult". I've been a member for many year and only made one or two requests. Most everything has been discussed before at length...

boxhead · #20 (**permalink**) 11-04-2010, 07:58 AM

I am not saying how they run it is a bad thing, it is there playground so they run the rules.

Just not very social, but very technical, so many hours of reading coming up for me, Thanks again.