Bored the other weekend (rear beam triangulation).

Craig you have to much spare time on your hands....

looking good

 

I want to add these but also avoid combes daft regs regarding rose joints and suspension. Strengthenging rods are'nt suspension per-say are they??

 

depends if you beat people I suspect Billo

Very nice work there - also on my to-do list - still deciding whether to fit the heavier Mk2/3 golf beam to my ibiza though and dont want to fab twice

will probably stay with lighter ibiza beam as its been ok on my car so far (and on badgerwagon) with slicks fitted - and on ibiza the tank is ahead of the beam so no clearance issues

I have mixed thoughts on how necessary this is for circuit racing - even with slicks - on a Mk1 beam maybe as its got far fewer strengthening plates than later items

I can see it may be useful for rallying to stop big sideloads from clouting banks bending the beam

But I kind of recall reading somewhere that the VWM cross brace design with the towers was no where near as simple as it looks - its not just for sideloads - it actually imparts beneficial camber change on the axle in lean - cannot remember the details though - from looking at it looks like it might induce negative camber on the outside wheel in lean - any uni attendees got access to a simulation package ?

(off to shed to make a stick model.....)

Maybe the towers were just to clear the exhaust and tank though ?

 

Nothing to lose and unboltable / back of the grid job if you get a decision after qualifying....

 

If pugs can be independant rear suspension I may be ok.. lol

when does strengthening become suspension? Its not a pivoting mechanism but one to hold the beam stable and for "safeties" sake thats a good thing.

controlled beam deflection for consistent geometry would be a start me thinks, if perhaps like rob says there was some geometry benefit going on by deflection in a certain direction..

 

Well it's strengthening of course Suspension? Never occurred to me

 

touring cars were not allowed to have additional 'pivots' in the rear beam so they designed them with 'flextures' - PMSL - not pivots but areas of metal engineered to be bendy.....

seem to recall you being bothered about arb droplinks being rose jointed - similar situation with this perhaps but if pugs run independent rear.....you have no issues

 

ARB I would consider as a suspension component (active) but adding stiffening tie bars is'nt suspension?
lol.. they wont like the car anyhows as its too yellow or something

 

I always wondered if it was possible to temper the rear beam and alter its flexibility properties, anyone know

Could be handy if it would work where the regulations are very prohibitive about modifications

 

In theory yes.... but because its a fabricated part Im not sure how the weld strength and fracture tougthness may be affected.

On a FWD car I believe you want the rear wheel to stay in the same position or steer in the same direction as the fronts. If the rear beam deflects its going to steer the rear of the car in the opposite direction..SPIN! so anything to reduce this deflection is going to be advantageous?

 

Two schools of thought: some will argue on Vortex like this > that you want the rear beam to toe out under load, for your set up.

Others say you don't want it pinging in and out, load-sensitively, if you're going to get it to move - ie you want consistency over momentary toe out, and you set up accordingly.

So some serious levels of testing are required to make the call....

 

Need 2 beams, a skid pan and an infa red thermometer.. I'l try it at some point

 

Prelude VTEC, 4WS, counter steers the rear wheels in fast corners on track.


Makes the car awesome in the wet. Although in the dry you can't provoke the back properly - as soon as it starts to slide the steering angle on the rear comes off - so any slide gets stopped straight away, leading back into understeer.

With the prelude I'd want 4ws turned on for the wet, and turned off for the dry.

 

Basically you're looking for something that's consistent and adjustable at the wheel.

 

In reply to Bill, i had some 21mm ID 2mm wall thickness CDS tube lying in the garage so just used that, the joints, insert, half nuts etc. are 5/8" as that was all i could get hold of next day with matched inserts. I had to shave a ball hair off the inserts in the lathe to get them to fit although it took the plating off which aided the welding. Oh yeah 5/8" is equivalent M16 in metric a bit extreme

And Dave (VR6T) you can never have enough time i only wish you could get more hours in the day sometimes and didnt get tired
Hows the MK3 coming ?

 

Fine and danny thanks, just need to get a down pipe fabed and finish it off, your right three MOT's last week and a MK4 in bits its never a dull moment....

 

I think I recall the carvell lupo having similar tie bars, but on that one they bent at odd angles... using slicks in VW cup action, but the beams movement was in no one direction.

for me, consistency is what I would like to dial in.. set it, and it stays there no matter what I am doing.

thanks for the info.. cheers for that

 

Not bad





Before anyone says the powder coat will be coming off the stub axle faces i just forgot to tell them to mask it up

 

looks the buisness, nice one

 

They were very lightweight in mfr - much thinner than VWM spec - which is likely (IMO) to be why they deformed.