Pneall and bumpsteer on Classic Revival.

Mando · #1 (**permalink**) 11-12-2004, 01:34 AM

Hi Phil,
I was talking with Aussie Mike soon after the Nationals and he told me that you were trying to reduce bumpsteer by installing 25mm spacers between the frame mounting points and the steering rack. Have you had any success. Can you tell any differance?

Regards

pneall · #2 (**permalink**) 11-14-2004, 01:07 PM

Mando,

I am not back on the road yet as I am making a few other changes.

Leeroy gave me the idea and he believes the bump steer is almost eliminated. The wheels noticeably changed toe (at full droop) when I added tha spacer . I wil need to realign wheels then try out. Maybe by the weekend.

Took up you idea of extra support for front of body and have added support from chassis up to bonnet support.

I'll post results of steering mod once knowm

cheers , Phil

Bathrone · #3 (**permalink**) 11-15-2004, 06:21 PM

There is software programs like susprog3d that would give you advantages in trying different setups without the hassle of having to fabricate and fit the prototypes.

I would try to use one of those and see what the outcomes is with the geometry cos you could try over 100 of them a day that way.

BTW, what is the measured bumpsteer of the classic revival kit?

Has anyone done a graph of camber change VS suspension articulation?

Is the camber adjustable?

Is the castor adjustable?

Whats the polar moment of interia like in the Classic Revival against other kits or are basically all the kits layed out pretty much the same?

Aussie Mike · #4 (**permalink**) 11-15-2004, 06:35 PM

Camber is adjustable front and rear. Toe is adjustable front and rear and castor is adjustable on the front.

I figure Polar movement is going to be similar for most kits ans they have very similar weight distributions and wheel base. Ther main thing that will efect it would be engine choice and how far back in the frame it's positioned.

I've got the bump steer graph at home some where. I'll have to see if I can find it.

pneall · #5 (**permalink**) 11-15-2004, 06:53 PM

Mike,

Is CR only manufacturer with steering rack behind front wheels?

Phil

Aussie Mike · #6 (**permalink**) 11-15-2004, 07:28 PM

Most of the ones with in Aus are rear steer. The Jag front end equiped cars are, as are the Torana cars I believe.

Robnel is front steer and I think the newer DRB 2000 has the jag front modified for front steer.

Cheers

boxhead · #7 (**permalink**) 11-15-2004, 07:36 PM

I can scan my bump steer graph when I get home tonight if you want to see it.

Bathrone · #8 (**permalink**) 11-16-2004, 04:19 PM

I'd be thankful if you could boxhead

boxhead · #9 (**permalink**) 11-17-2004, 03:32 AM

Here is the plotted graph that came with my Classic Revival kit.

pneall · #10 (**permalink**) 11-22-2004, 10:08 PM

My alloy radiator wants to be a fountain instead of a radiator so it has gone back to Qld for inspection

so it will be a few weeks before I can report on the bump steer mod.

Guess I will just play with my nuts

until the rad comes back.

Phil

Aussie Mike · #11 (**permalink**) 11-22-2004, 10:21 PM

I've been playing with your nuts all week end. I spose it's about time I gave them back.

I'm going to go and play with my wifes rear end*.

*The rear wheel bearings and uni joints in her Jag need replacing.

Cheers

boxhead · #12 (**permalink**) 12-26-2004, 03:03 AM

I was just cruiseing through some build pics on the site when I came accross this one.

I realise it is fairly easy to make adaptor bolts to fit the rose joint type ends above the standard jag arm but when I saw this I thought this could be even easier.
You could make the arm to whatever hiec=ght you needed to get the rack on a level plane.

Rebel1 · #13 (**permalink**) 12-26-2004, 03:33 AM

Boxhead, that steering arm on the jag upright is very similiar (if not the same) as the DRB2000's.

It's a welded up arrangement which aligns with a very high mounted steering rack.

But, as you say, if they can do it so can anyone.

Cheers

boxhead · #14 (**permalink**) 12-26-2004, 03:35 AM

Yeah I dont think it would be hard to make, and I have a tappered reamer in my tool box from back in my buggy raceing days (used to fit hk holden rod ends to vw steering arm

pneall · #15 (**permalink**) 01-30-2005, 01:52 PM

Finally back on the road and have completed mod to steering.

Dropping the rack by 25 mm has almost eliminated the droop steer and also helped the bump steer.Also needed to thread extra section of tie rod to get enough adjustment.

The car feels a whole lot better on the road and goes around corners much better. Thanks Leeroy for putting me on to this.

Only way to get things any better will be to shorten rack .

Spent yesterday with the NSW Cobra Club at Eastern Creek skid pan. This has got to be the best way to see if your Cobra is handling and braking well. Had a ball.

Phil

Bathrone · #16 (**permalink**) 01-30-2005, 04:04 PM

Phil, do you have metrics on what the new geometries are now? Thanks

pneall · #17 (**permalink**) 01-30-2005, 04:16 PM

Only have new toe, castor figures . No actual bump /droop plotting. Just know it drives better.

Probably come up with actual figures once I go to next step of shortening the rack.

Phil

Rebel1 · #18 (**permalink**) 01-30-2005, 05:29 PM

Hi Guys

You may already be keeping track of this thread on the gasshole site.

http://www.gasholes.com/smf/index.php?topic=3232.540

Interesting little gadget Morris made.......excellent way to fine tune the suspension. Make sure you read all the threads.

Maybe I'll have a friendly chat to Uncle Aussie mike or uncle ozvenom to make one of these and share it around.

Aussie Mike · #19 (**permalink**) 01-30-2005, 05:35 PM

Already working on a similar setup. I bought a second dial indicator last year and I'm part way through welding up a frame. Just got to pull finger and finish it since I want to check the results on my heim joint steering mods.

Cheers

Rebel1 · #20 (**permalink**) 01-30-2005, 06:37 PM

Now....why did I know you were working on something similiar?

Jag stud pattern thanks mike.