Even a modest weight reduction of the uprights is probably worth achieving, since it is unsprung mass which you're reducing. The ratio of unsprung/sprung mass should always be kept as low as possible, the sprung mass of the lightweight is very low, so reducing the unsprung mass would seem a good move. Using lighter weight uprights also seems to me a better way to achieve this than using inboard dampers, which I've heard talk of.

As to where you could get suitable uprights, and whether capri/cortina hubs fit, I've no idea.

The design of the lightweight makes inboard dampers pretty much a non starter but they are a good move. Any aftermarket alloy hub carrier or the cortina ones will move the top balljoint outward far enough to suggest that refabricating the top wishbone will be needed to retain strength. Not difficult and by incorporating adjustable rose joints on the inboard ends will allow tuning of castor angles.

Interestingly the lightweight on show at Exeter last weekend had cast alloy uprights and a Duratec engine.

 

Nigel

Dan, no, the 75-80lbs of the hubs and brakes is half my weight....not riz's weight...tho i have gained a few pds in my old age, i am still w/in the l/w (car) range!!

 

Sorry about getting frustrated w/ the negative responses. My fault.

Tim, yes, reducing the unsprung weight is a good idea. The weight (overall, and some unsprung, and some rotating) and KPI are my reasons for proposing this switch.

 

However, what are ur and Nigel's concerns w/ the inboard shocks? Are you concerned that the interior sections of the lightweight will not be strong enough for them?

Nigel, yes, just getting a longer adjustable rose joint is probably not the best way to handle the new KPI of the cortina/etc uprights. Would probably overly increase the "lever" force on those threads. And, you are right, it wouldnt be that hard to simply extend further the end of the top wishbone. And then i would just need to thread into it the correct rose joint for the cortina/etc uprights.

 

The bottom would be easier, since it doesn't move. ie, all that would be needed is new ball joint, to allow it to be hooked up to the cortina upright....

they wernt negative responsess,im sorry if it came across that way

 

but in thid country in the rgb championship(for bec) all the cars are raced to a certain weight,and very few run alloy hubs etc,i agree on the unsprung weight issue,but if its for road and track its not worth it, 99% of the lsis kits use sierra hubs with no problem,the others use cortina etc because they are based on the chapman book "build your own sports car for £250"

 

it wont inprove your handling or traction etc in corners

 

marc nordons race car weighed in at 397kg with race leader stuff on,my car was 420 at sva with all sierra stuff,so thats only a difference of 23kg

 

he also had no interior,fibreglss seats and 13 inch lightweight alloys,no clocks(just a digidash)

 

ps the cars were identical in every other way including the engine

 

the mnr cars also run with the "ackerman" princible built into the geometry to give better handling than normal

 

i still think you could find a better way of inproving the front geometry of the car than changing the hubs,hundreds in this country have

The increased KPI of the sierra hubs will have a negative impact on handling.

 

As will the increased unsprung weight, and increased overall weight.

 

I cannot comment on the overall weight of your car vs. Marc's car. I would instead like to keep the discussion on the sierra hubs and brakes, vs cortina/etc uprights/hubs/brakes.

 

-sm

i give up,have fun

Sorry, Riz. Don't mean to be contentious.

 

I think the unspring weight issue is fairly self-explanatory.

 

In terms of the KPI, the problem, as i understand it, is the KPI causing a significant camber change as you turn the wheels.

 

Hope that helps.

 

-sm

Sorry about my "Negative" Response earlier.

 

Heres another one

 

You brits need to work on that english thing!!

 

 

 

Regardless of what Richard is meant

 

 

ScotMac, your post count is going to be going up very quickly with the amount of posts you have in a row to cover each point

 

I study English Language and English Literature and my english is worse than most

 

can i be upfront with my naivety and ask why inboard shocks are better?

I've got a funny feeling you are going to get frustrated very quickly with your kit with your KPI's and all.

 

Don't forget you have bought probably the cheapest kit car on the market. If you are losing sleep over the angle of the sierra hubs (or whatever the issue is) I can't imagine what your feelings will be when you start getting into the build.

 

Am I right in thinking you haven't got your kit yet?

If you are losing sleep over the angle of the sierra hubs (or whatever the issue is)

Couldn’t agree more its a track day "fun" car you are going to build which is also designed to be used as a road car, don’t expect it to be competitive with a 1960's technology engine in it so why worry about the suspension at this stage? Build the thing (you’ll have more to think about than KPI) run it then think about doing mods to improve it

 

Rant over

And to be helpful.... how about these? http://www.nfauto.co.uk/alloy_uprights.htm

 

£1,500. That's cheaper than some I've seen. If they can't do export to you then I may be able to help.

 

The guys are right, the Robin Hoods we all know & love are not race bred mega machines, they are a cheap way into this type of fun & as such are really good value for money but don't expect the tolerances to be spot on etc. How good a car it is will largely depend on the builder & their ability to solve the numerous problems that arise in inventive ways.

 

In my opinion if you are looking for a real fast race machine you are better off spending your money on a different type of kit to start with than face all the hassle, frustration & expense (£1500 just for uprights is a substantial investment) of improving a RH to a standard you are happy with.

 

It's completely different in the UK, I reckon that if Robin Hood were a US company they would have been sued & gone out of business from legal expense a long time ago!

 

If you're having trouble with export of other kits, give me a call, I'd be happy to try help you import one. If you want to discuss then PM me for a number...

 

Dan

LOL....ok, guess i deserved all that...

 

However:

 

First of all, this will be used almost exclusively as a race/track car.

 

Secondly, why would i build it using something i am not happy w/ (sierra uprights), and then have to change them later, if i can instead build w/ something i am happy w/ upfront??

 

Thirdly, the engine is 2005 duratec I4. One of the most modern engines avaiable, and already (in only 3 years) used in many different racing series.

 

Fourthly, yes, i have not received my kit (Dec 5th)...that's why i am posting in the donor room!!!

 

Fifthly, the english thing was a joke!!! I think it is funny when americans and brits can't understand each other...because we speak a different language!!!

 

Doc/Jim, you can read here and other threads why inboards are better. But, in general, they reduce unsprung weight and slightly increase aerodynamics (unsprung weight is main point).

 

Anything else???

 

Now can we get back to the topic at hand...ie, the cortina/capri uprights?

Nigel (or anyone else), did you get a picture of the l/w w/ the alloy uprights? Any idea what kind they were?

 

Cheers, -sm