RF #12 "Race" Chassis

re: RF #12 "Race" Chassis

Hi Jim. Yeah, the problem is that because my steering arms mount on top of the control arm from the upright, the taper didn't suit at all. This hole was then reamed out in that direction, effectively reversing the cone shaped hole. I tried just about every possible tie rod end available without success.

Happily, problem has been solved, and now allows me even more adjustment down there!
 
re: RF #12 "Race" Chassis

Wow, that's some nice trans work there Troy. That's the kind of trans that appeals to me, but just a little out of my range right now. I'll be very interested to see how it performs though. May get my car back on the track in a month or two though, so hopefully I'll get a bit of a head start on you in development time - I'll need it by the looks of your beast!

Cheers,

Julian
 
re: RF #12 "Race" Chassis

Troy,

That transaxle is one sexy beast. Have you considered using it as a stressed member? It looks like it is designed to take suspension arms.
 
Last edited:
re: RF #12 "Race" Chassis

Troy,
I would like to see a side shot of the rear of the trans in your chassis. It looks as though it will stick out a bit. It looks like a monster setup though.

Bill
 
re: RF #12 "Race" Chassis

Good grief!! I think you'll need to tow a box trailer to carry half the transaxle. But I'm sure you've measured and worked it all out.
 

Clayton

Supporter
re: RF #12 "Race" Chassis

Nice work Troy
I see you have your workshop up and running.
Still not sold on your engine choice though :lipsrsealed:
Cant wait to see the rest of the goodies.

Clayton
 
re: RF #12 "Race" Chassis

Hi all!

Tom, yes. The new suspension arms will mount directly to the pick-up points on the transmission. This new rear design also allows for a simpler adjustable anti-roll bar mounting than previously thought. The whole shooting match will be solid mounted, and the only need for any chassis members past the rear transmission mounts will be to locate the rear clip, the oil coolers and tunnel diffuser.

Bill and Dalton, I'll post another few pics soon. From where it is in that picture, it still had another 70mm to go forward, and 10mm down at the front. My old mate Mr. Makita came to visit, and the existing cross member at the back was removed about 2 hrs ago. All slips in nicely, and fits within the confines of the body. Phew!

Clayton, the new shed works wonders for motivation! With regards to the Chev, it almost found a new home between it's procurement and the arrival of the gearbox. I bought a '96 HSV GTS/R and thought it'd look ok in the yellow engine bay. Steady on, I thought - particularly since all the one off stuff already made for his set up was already sitting in the shed! At least I have a cool tow car, for when the LS2 lets go ;)
 
re: RF #12 "Race" Chassis

Troy,

will you need to modify the front end to get similar camber gain front to rear? With regards to the rear suspension, will you be fabricating the whole thing, or are there some parts out there that can be modified to get you the track and fore/aft placement you are looking for?

This should turn out really nice - I'd love to fit a similar set up on my car.
 
re: RF #12 "Race" Chassis

Hi Tom, my front end is pretty much a fully adjustable set up, that will be corrected once all is installed. I will be having most of the parts fab'd to suit, though there is an option to buy parts off the shelf from a company in the UK that has a race proven set up for the Prosport 3000 cars. Some of these are running the Hewland NLT, which is the same as the Elite gearbox (front half, at least). This set up also has push rod suspension incorporated - better for my diffuser tunnels!

I will be visiting their factory next week, and may be influenced into their arrangement, despite the price tag! (the easy option). The only thing I would have to change is the adapter plate to the trans, as they hang some suspension pivot points off it.

Also, their cars run true wishbones on the rear with toe links - no trailing arms.
 
re: RF #12 "Race" Chassis

uprights tucked inside rear wheels = bigger tunnels.
If you've seen a Porsche 962 etc, as well as some other prototype chassis, the rear suspension arms are hung on carriers which are bolted to the gearbox. I guess the purpose is to shorten the arms so that they produce similar geometry to the front.

can't wait to see this build up.
 
re: RF #12 "Race" Chassis

Quick update. The sun was out the other day while I was measuring up for all of the engine and trans mounts, so I decided to grab a quick pic of the car for the thread. All of the chassis behind the removable cross brace will be removed as all will be hung from the transmission. Yep, it's all gotta go!
 

Attachments

re: RF #12 "Race" Chassis

So, just for info on what I've been up to in relation to the rear suspension on RF12.

The rear uprights are not fully modelled, but the pick up geometry and sizing are accurate, and have been set at 1 degree negative camber. I currently have no castor dialed in, but will model the drag link connection points and connecting clevis bolts then test. Static Roll centre is 41mm above ground level.

The transmission is not the full model either, but just the info I need. The full STEP file on the transaxle is massive, and really slows the PC down!
 

Attachments

Re: RF "Race" Chassis 12

Just an update on RF 12.

I have the car now and am planning to continue with the original plan of a road registered race car. The motor will be the good old Windsor 5.0L and audi transaxle. The car will be painted up like the picture without silver stripe. I have always liked green GT40s and now is my chance to make this dream come true.

Interested to know if there are any other RF's out there with a similar rear suspension set up? I would really appreciate a few pics of the rear suspension and some feed back on how it works in the real world.

I am thinking of returning the car to the reverse A arm set up on standard RF's.


Cheers
Dave
 

Attachments

re: RF #12 "Race" Chassis

Hey mate, cool colour choice. Can't wait to see it finished up.

As far as the rear control arms go, Iain's RF117 originally left the factory with that arrangement, but was changed by Corsa during their re-design. So that leaves just Jim's RF105 with it. He also has a cool idea for the rear clip hinge locations! (Pics of Jim's car attached)

Clayton (Otto69) with #RF066 in N.T. changed his rear chassis to the higher rear cross-member, but kept the reverse A arm (different mounting position to std RF).
 

Attachments

re: RF #12 "Race" Chassis

Cheers troy, I have contacted Jim.

Heading to Rick's when i get back from Site to check his RF out. Nothing like looking at a finished car for inspiration......
 
re: RF #12 "Race" Chassis

Yes Dave I have that set up.
2 lower laterals. It cancels the rear bump steer out.
My lower inner pick up points are lower than them.
Troys upper lateral looks longer(on a bracket), that can reduce rear neg gain but it fundamentaly the same.

I also made a rear roll centre adjuster on each upper inner laterals.

It took a little sorting on my part ( lack of rear eng car experiance).
I am extremly happy with the way the car behave's
I have never had a car that I can get on the power so early and I am still exploring that.

It is forgiving and likes to to be driven through a corner,like a race car,if I lift it does not get out of shape.
I have bounced it of ripple strips and you can stay in it with confidence.

The set up issue I had was it had to much rear grip and induced understeer.
I reduced the rear toe to 1mm. neg is 3/4 deg.
I changed the rear R/Centre ht to knock off some grip to get the balance ,Front and rear R/Centres are at about 30mm give or take a mill.

I would work with what you have, lower laterals need to be on the same plane.
I have talked to a few 40 owners and my car does not have inherant rear eng handling issues.

Jim
 

Attachments

Last edited:
Top