306 replies to this topic

[MAXR]

 

So, what are you going to do captain? Fit harder springs or wait for the clubsport and upgrade to ntr40?

 

TBH - The first thing I did was to bid on a Caterham Mega Grad race car (150bhp, wide track suspension, 520kg, aero screen) but after Lady V hit the ceiling and asked where I would store it (and the associated tow car) I decided it was perhaps more sensible to spend money on the VX where I can hide fit the shiny parts underneath the car and accurately claim it was essential maintenance.... Fortunately for my marriage the Caterham didn't meet reserve (if anyone has a spare garage space near south Essex, I could be interested..)

 

Anyway, the current plan is to try harder springs on the NSS and some EP negative camber steering arms. The NSS can handle up to 600lb springs which I believe is pretty much on the margin of road usability anyway. I want to keep the road usability otherwise I may just as well get a 'track only' car and tow car...

 

 

 

Man Maths at it's best!

[SteveA]

You give up too easily Kev

 

http://www.pistonhea...OU4UuaD80CXf.03

[Captain Vimes]

You give up too easily Kev

 

http://www.pistonhea...OU4UuaD80CXf.03

 

Not helping!

 

I took the vx for a blast this evening and it reminded me how great it is to be able to just go out for a spin, so I need something road legal and fun. (It also reminded me the SC belt is slipping - plastic sh*t box...)

 

 

This is what I was bidding on http://www.ebay.co.u...984.m1435.l2649 - it states it's a super grad (135bhp) but the spec and previous owner suggest it's actually a mega (wide track suspension, 150bhp, straight cut box, aero screen, no lights). 

[SteveA]

They can all be made to be road legal and most racecars will be if they have been through the academy. You can also buy full wet weather gear so you can store it outside. No excuse

 

Mega or Sigmax (higher rev limit and an LSD) are the way to go in graduates. Supersport is the equivalent in the Avon championship (albeit with a little less power and different tyres)

[Captain Vimes]

Boring nerd alert... I stuck all the spring rates from this thread into a table to get an idea of where to go with mine.

I'm going to aim for 425/550 which seems to be on the cusp of needing helpers. Just figuring out whether to splash out on the helpers which will more than double the cost.

[Scuffers]

Not sure what your trying to achieve with said table?

 

dampers/tyres/ARB/ridehights/etc will all affect the choice.

[Captain Vimes]

They were all in my table but I didn't have the info. Just trying to figure out where to start.

[Scuffers]

if it was me, knowing how you drive, I would go with 500/650 (with 200/300 tenders) on Quantum single ways, along with a 1" ARB.

 

Longer term, springs are cheap, and if you progress, then it's cheap/easy enough to switch them out for stiffer later..

 

 

[chris_uk]

i agree with scuffs

[Exmantaa]

The need for helpers also depend on ride height and damper length.

But assuming you got sufficient length rears (for droop) and "reasonable" ride height that looks ok, you can go away with only helpers on the 550 rears and single 425 springs on the front. (just....)

Any stiffer or going lower, you will need front helpers too.

 

Edited by Exmantaa, 21 November 2015 - 03:23 PM.

[Scuffers]

The need for helpers also depend on ride height and damper length.

But assuming you got sufficient length rears (for droop) and "reasonable" ride height that looks ok, you can go away with only helpers on the 550 rears and single 425 springs on the front. (just....)

Any stiffer or going lower, you will need front helpers too.

 

yes and no

 

depends if they are simply 'helpers' to take up the slack or 'tenders' to add some rate.

[fiveoclock]

For your table I have NTR40 500/650 with 150 helpers on the rear and a 1" bar

[Jason]

On the EP 1" ARB, supposedly the Pilbeam one is loads better.  Mine is set to middle setting and feels fine on the road.
 

Now it could be bollocks, but I'm told the pilbeam ARB is more linear than the EP 1" one

Also if the EP one is solid the Pilbeam one will be lighter

I was certainly sucked in and bought one, not fitted it yet tho

 

I saw the comments from Chris Randall on the VX220 forum regarding these 2 anti-roll bars and it's pretty hard to ignore advice from someone like him, although I did, EP one was £100 cheaper I'll let you know what my thoughts about the bar once fitted, for what little thats worth!

Edited by Jason, 21 November 2015 - 09:07 PM.

[Scuffers]

Lol! I'm not going to begin to say how laughable the 'linear' claim is, What i will say is where do you think the extra £100 goes?

[Scuffers]

Ps, as i am sure some of you know, EP setup a test rig for ARB's, we tested every bar out there, and i have the test data tabled and graphed.

[Jason]

So what does the table and graph show? The bars do the same job? Is the stiffest settings on my EP irrelevant as suggested. I'm not one for adjusting anyway so it staying one one setting. The way I read the quote Mr Randall played a part in development of both bars.

[Scuffers]

So what does the table and graph show? The bars do the same job? Is the stiffest settings on my EP irrelevant as suggested. I'm not one for adjusting anyway so it staying one one setting.

The way I read the quote Mr Randall played a part in development of both bars.

read into it as you will.
 
The history is pretty straight forward, I had the original Pilbeam 1" ARB back in 1998 (along with some other stuff), this got damaged when Mr Randall binned my car into the wall at Silverstone in 2005.
 
I then got Geary to make their 1" bars, initially as a batch of 6, then as Elise Trophy took off, they became a std stock item.
 
ie. this one:
 

 
the design changed in mid-2014 to make them easier to make/weld:
 

 
and it also went from 5 setting (where the stiffest hole could not really be used) to 3.
 
this design is now common to both the 1", 1⅛" and 7/8" EP ARB's.

 

so, yes, his part was in trashing my old Pilbeam one so I needed a new one.

 

as for function, a 1" ARB assuming you have not designed something really wacky, will be much the same in stiffness as any other, steel's modulus of elasticity is a constant (and even between different grades of steel it has little variance, hence why a T45 ARB is no better in stiffness than plain CDS).

 

(If you calculate the stiffness on paper from this knowing the tube dimensions, then surprisingly enough, you come out with pretty much the same answer as when you measure one.)

 

Geary even made up a 'blade' adjustable one:

 

 

but when tested out, it was worse than the basic old design (too much flex in the blades and mountings)

 

here's a vid showing the test rig we used:

 

 

So, want to keep commenting on about who has done what in the past, and who actually has done the work?

 

 

[Jason]

Thank you Scuffers that really explains this in more detail. Seems like over time the confusion over the EP MK1 & 2 version in terms of settings. As would explain the comment that the only the softest is relevant although an exaggeration of your own comment. (Chinese Whispers and all that). So did you have measurement from other brands apart from EP. Interested to know the comparative stiffness of standard to 1" to others beams. I know you just said that steel is steel so performance is very similar but comparative testing been done and curiosity has me wanting to know also I think the pilbeam is not as thick diameter to make it not as stiff per their design.

[Scuffers]

What confusion? they are both 1", they both perform the same (within the bounds of the setting they have), etc etc.

 

(Also worth mentioning that the Pilbeam one has changed over time).

 

Cover this completely, some notes:

 

1) no matter what steel you make an ARB from, they will all be about the same stiffness (it's less than 5% between plain low-carbon steel and top spec, high % CrMo steels)

 

2) biggest factor in ARB stiffness is the OD of the tube, then the gauge (wall thickness).

 

3) assuming you don't do something dumb with the design, the 'lever' on the ends of the ARB make little odds, stiffness is defined by the distance from the bar to the drop-link (at 90 degrees to the bar).

 

4) no matter how stiff the bar is, the way it's mounted on the chassis will add some compliance, reducing the effective rate.

 

5) the pick-up point on the wishbone for the ARB drop-link is inboard from the dampers pick-up point, so it's effective rate on either the spring/damper & wheel rate will be a ratio (and less than it's absolute rate).

 

Lastly, in track testing/racing/etc I have yet to get to too stiff an ARB (hence Testing [color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]1⅛" bars)[/color]

[thejoaoserra]

Boring nerd alert... I stuck all the spring rates from this thread into a table to get an idea of where to go with mine.

I'm going to aim for 425/550 which seems to be on the cusp of needing helpers. Just figuring out whether to splash out on the helpers which will more than double the cost.

Nice table!

Can a vx n/a be comfortable on road with the 425/550 spring rates on nss2? Will it be better on comfort than oem suspension, or much worst? 

I assume that with those spring rates it should be even better on track... 

Edited by thejoaoserra, 23 November 2015 - 10:29 PM.