CSX3170 gets killed in autox

[Jdata]

Are the kuhmos still available? So basically you're going to have to fool your suspension from front to rear and thinking it's longer wheelbase by slowing the transfer so you can somehow keep your lateral grip be the same. Are movable or sliding ballast allowable? ��

[t walgamuth]

I think not in SCCA.

[Cobra #3170]

Kuhmo's for the ACR are no longer available as far as I know I think the ones we bought new were date coded 2017. Concrete can take higher rates of weight transfer than asphalt we just need to do a better job of tuning on concrete. The cars size helps and hurts times, just need to do a better job minimizing the hurt. I am just beginning a new project to make the car more competitive in CAM-S but it will take about 2 months to complete. I will post everything here once it is done including how much it helped.
I wish pictures were easier since nothing is low resolution anymore. Maybe I will do a video. I am having cataract surgery Thursday so that will set me back a bit but I am fully committed to making this upgrade, no matter how long it takes. Lots of design work and machined parts should be interesting for people that like the technical side. Keeping a 54 year old car competitive gets tougher every year!

[t walgamuth]

I would like to compete in Cam s but I would need nearly 400# of ballast to be legal. About 200 for XP so that is more doable.

[Cobra #3170]

Originally Posted by t walgamuth

I would like to compete in Cam s but I would need nearly 400# of ballast to be legal. About 200 for XP so that is more doable.

You could not have chosen a tougher class, they allow extensive aero modifications and have some of the best drivers in the country competing.
You probably don't care but you will be 6-7 seconds behind a good XP carand maybe more.

[t walgamuth]

Do you think Cam s would be easier? Does it allow any aero?

What class have you been running?

[Cobra #3170]

Originally Posted by t walgamuth

Do you think Cam s would be easier? Does it allow any aero?

What class have you been running?

I have run AP before they dropped it was second nationally in 1977 and 1978 ran Emod when it came out, think I was 3rd. Started running CAM-S about 5 years ago and Scott won the shootout and Class whenever it did not rain.
Corvette people kept crying and complaining until they had Cobras up to 2500 pounds. We carry 200 lbs of ballast and it does not hurt, in fact the car is faster weighted up because of 200 TW tires. They do not allow wings and only minimal splitters and spoilers. You would be better off there than a race tire class like XP. Engine mods are unlimited the only restrictions are weight, tires and aero

[t walgamuth]

Maybe next year. I am still sorting the car now. The XP class seldom has a large field at the local events. I pick a guy I know is similar to me in skill and compete against him. At present I am almost equal to a guy who runs a very clean 99 Miata in ES, and has been running the same car since it was new.

When I beat him I will know I am improving.

[twobjshelbys]

Are you going to be at the Colorado Good Guys show this weekend? Is that your car in the auto cross promo pic? We were back there for the Shelby American Collection party. I'm thinking of waiting a week next year for the Good Guys.

[t walgamuth]

Sounds like fun.

[Cobra #3170]

Originally Posted by twobjshelbys

Are you going to be at the Colorado Good Guys show this weekend? Is that your car in the auto cross promo pic? We were back there for the Shelby American Collection party. I'm thinking of waiting a week next year for the Good Guys.

No Tony, unfortunately we missed SCCA nationals and Goodguys Colorado.
I am in the middle of a major upgrade that has proven to be far more difficult and expensive than I ever anticipated. Car will not be operational till late this month or early October. I have been working on it since mid July. When it is done and tested I will list all the details here. Yes they are using the car in some Goodguys promotions.

[snakeeyes]

Originally Posted by Cobra #3170

We carry 200 lbs of ballast and it does not hurt, in fact the car is faster weighted up because of 200 TW tires.

It’s ironic with a lightweight, high-hp car, isn’t it? I spent a great deal of time sweating blood to make my Beck Lister as light as possible when I was building it. She ended up at 1,976 pounds with a half-tank of gas so I was happy with that. In multiple track days the best lap I ever ran was with a 240-pound passenger, LOL. Don’t know if that’s a reflection of my need to cross-weight the car, if the extra weight helped the tires get up to temp, or if I just drive faster when I’m trying to impress.

Regarding aero, when I was tracking my Lister a lot I didn’t want to drill a bunch of holes in the body. I ended up mounting an APR wing to the roll bar (my bar extends the width of the car unlike a typical Cobra single-hoop design, so it was easy to do), making a splitter out of some high-impact material, fabbing a defuser from sheet metal, and then adapting some generic canards. The splitter and defuser bolt on but they’re both on the underside of the body where you’d never see the holes. The only visible holes are for the canards, and they’re pretty tiny. My “aero package” was all seat-of-the-pants but the car got faster afterwards, whether that was a reflection of aero benefits or just my increased confidence in it.

[Cobra #3170]

Originally Posted by snakeeyes

It’s ironic with a lightweight, high-hp car, isn’t it? I spent a great deal of time sweating blood to make my Beck Lister as light as possible when I was building it. She ended up at 1,976 pounds with a half-tank of gas so I was happy with that. In multiple track days the best lap I ever ran was with a 240-pound passenger, LOL. Don’t know if that’s a reflection of my need to cross-weight the car, if the extra weight helped the tires get up to temp, or if I just drive faster when I’m trying to impress.

Regarding aero, when I was tracking my Lister a lot I didn’t want to drill a bunch of holes in the body. I ended up mounting an APR wing to the roll bar (my bar extends the width of the car unlike a typical Cobra single-hoop design, so it was easy to do), making a splitter out of some high-impact material, fabbing a defuser from sheet metal, and then adapting some generic canards. The splitter and defuser bolt on but they’re both on the underside of the body where you’d never see the holes. The only visible holes are for the canards, and they’re pretty tiny. My “aero package” was all seat-of-the-pants but the car got faster afterwards, whether that was a reflection of aero benefits or just my increased confidence in it.

What tires were you running? In the past I found that running on Hoosier A6 or A7 at lower weight helped but with 200 TW you don't get the mechanical grip from the tread rubber conforming to pavement irregularities.

I can't do any aero on the Cobra because I don't want to spoil the original appearance. I did put a large wing on my 2005 Ford GT, added a much longer front splitter with shields for the front tires. I also lowered it about 2" and added full contact skirts to seal the diffuser air using conveyor belt material.
The car was scary because it stuck so well I could not sense the limit and I know if exceeded it would just let go. I ran it at Big Willow and found that it was 10 miles an hour faster around turn 2 than it was with out the aero upgrades. I am sure a really good driver could have gotten into the low 20's with it. It just scared me though, here it is on the front straight at Willow

https://www.youtube.com/watch?v=RsQoE1T-aNs

[snakeeyes]

That GT is a bad bear! Nice video.

I was doing a mix of AX and track days with my Lister. I tried R6 Hoosiers but the tire I actually liked the most was the Kumho V710, which I guess is now supplanted by the V720. It seemed to offer the best combination of predictability and grip. It also wore like iron but with a 2,000-pound car tire wear was never going to be a big issue. I was using the same tires for AX and track days.



I certainly understand not wanting to touch the bodywork on your car. Before I settled on a roll bar-mounted wing, I was looking into fabricating one that actually mounted inside the trunk. But that would be difficult with a Cobra because the trunk lid is cut so far down into the rear bodywork; on the Lister the opening was at belt-height so it was a more viable option. I don’t know how you’d be able to mount a splitter on the front, given the oil cooler opening on the chin, and you’d have to run your support stanchions through the fresh-air vents or something. Not easy!