4350 replies to this topic

[Scuffers]

Lol, not sure i would call it a marketing campaign! As said, this thread is about Mikes car, and how it can be made faster for next year. Now, i have no problem discussing what can be done to VXs in general, but as said, would be better in another thread, and i have no intentions of trying to push stuff on you guys.

[chris_uk]

Best thing that can be done to mikes car imo is get someone who can drive the vx chassis well and also has the ability to set it up. Scuffers, interested to know what you think about the way mikes shocks are setup, generally they are set 2 clicks harder on the front than back, personally this feels wrong to me but mike loves it. What are your thoughts?

[Scuffers]

Best thing that can be done to mikes car imo is get someone who can drive the vx chassis well and also has the ability to set it up.

Scuffers, interested to know what you think about the way mikes shocks are setup, generally they are set 2 clicks harder on the front than back, personally this feels wrong to me but mike loves it. What are your thoughts?

Honestly?

Just Throw them in the bin, period.

In more general terms, yes normally you need more bump at the front, however that's being very simplistic, as it's where in the dampers speed range that's the important bit.

[JimmyJamJerusalem]

Ok no more hub talk in this thread, a new thread is available below http://www.vx220.org...364-vx-gt-hubs/ Excuse the crap link I'm on my iPhone Please Simon everybody (including myself) is very excited to know more about hubs so let's carry on Over there

[chris_uk]

Interesting, thanks. In regards to the speed range, do you have the data to give an idea of whats excellent, good, ok, crap, shite etc? I have my monotube graphs here and would like to see how they stack up. Ta.

[Scuffers]

Interesting, thanks.

In regards to the speed range, do you have the data to give an idea of whats excellent, good, ok, crap, shite etc?

I have my monotube graphs here and would like to see how they stack up.

Ta.

I am sure you won't be surprised to hear that I am less than keen to post up the dyno graphs for the Quantums, apart from the obvious issue, unless you have the plots to compare with from the same type of damper dyno using the same test methodology, comparisons can be very meaningless.

in general terms, here's two different types of damper:





the first is a cheap twin-tube one typical of what you can buy for a few hundered £

the second is a Koni 3011 high pressure monoshock.

think to look at is the shape of the curves, at the far left in the very low velocity area is the important bit for what the car 'feels' like, as in the initial character of the steering etc. (this is what Lotus always used to play with to get the 'sporty feel' they go on about.)

as you go right up the velocity range, this determines how the car will react to progressively larger inputs, ie. by the time your at ~100mm/sec, that's significant bumps, like a typical exit curb.

now, in an ideal world, the last thing you want is a straight line, at very low speed (damper speed, not car), you want the damper to do almost nothing, so the wheels can move up and down and follow the track, most of it's work here is to damp the springs re-bound.

as you go up the speed range, you want to offer more resistance to the suspension, so, for example, as you brake hard/suddenly, you don't want the front of the car to pitch violently, the same goes for initial turn-in to corners.

as the speed still increase, ie, like your just about to go over an aggressive apex curve, you want the damper to let the wheel move relatively easy, so as not to pitch the car.

you then have to consider the requirements for re-bound, once again, as the speeds change, your asking for different levels of damping force.

now, going back to the graphs, typical twin-tubes etc. have exponential plots, ie, sod all at low speed and sh*t loads at high speed, this translates to a car that's under-damped for feel and fine control, but massively over-damped for big events (like kerbs, holes, etc)

so, what you then end up with is either adjusting them to be softer so it does not crash over the bumps, at which point you have almost no control at anything else, or harder so you have some pitch/stability control, but crash the bumps/kerbs so hard the car looses all composure.

if you look at the Second plot, you can see this has way more low speed, but the high speed does not rise at a hige rate.

these demonstrate the two basic shapes of the curves, there is a lot you can do in-between, for example, you can have digressive curves, ie. ones that are S shapes etc.

Now, back to Quantums, the way we have set these up is very much what I call 'light-touch' damping, ie, I am not using them to make the car feel stiff, (the stuffer you go, the less grip you have, springs are there to hold the cars weight, not the dampers, dampers are only there to control the speed of the transitions.)

what this means is that for a car setup right, you have full wheel-travel available at all times without the car flopping/pitching about, and still maintain excellent traction/grip, hence the reason I can throw Jamies car into the corners without it pitching violently and spitting me out backwards and also be able to get the power down out of the slow tight stuff.

now, most people will tell you that you can valve a damper to do anything you want, and yes, with a well designed damper that's mostly true, however, there are other things in damper design apart from the basic valve/shim setup, piston design is critical, it's not a case of right or wrong per say, but what's best suited to what your trying to get out of the damper.

Lastly, adjusters, having more clicks/adjusters is not a thing to be hailed as better, if the design of the damper is right to start with (for a given application) then there really is no point in having an adjuster on it - for example, F1 cars do not have adjustable dampers on them.

We (EP hat on here) came up with the Quantum Zero damper based on this, ie. we knew what we wanted the damper to do (for a 'sporty' road car setup) so just make a fixed damper that meet this spec (along with springs etc), these just work, and without having the stuff to make them adjustable, there is less to wear out, so they are likely to last way longer before their performance starts to degrade (talking many years here, to put this in context, the Quantum 1 and 2 ways that have been on cars now for 3+ years, and none have required re-gassing/rebuild yet, I expect the zero's to be even better in this respect).

Most dampers adjusters are a needle valve to by-pass the shim stack on the piston (Low speed on monotubes) or just buy-pass the oil flow (twin-tube), the more open this is, the less control the damper has, so if you are running your adjusters towards the fully open end of the scale, the less control you have, ie the more un-damped your getting, not a good thing as you have no real control any more.

Hope that helps? (sorry, got a bit unstructured...)

[chris_uk]

Just what i wanted to see. Thank you.

[Firthy]

Very interesting post again! that explains a lot of the feedback on here... regarding Mono tube and Twin Tube dampers. (people having trouble setting up the latter for a balance between control and stiffness) I have also driven a car on the latter twin tubes and could feel what the graph shows.


I know what my problem is with my setup now I currently run 10 (from hard) front 8 (from hard rear so rear stiffer) and as soon as i turn in at high speed if I am not super smooth on my input I get a dive of front roll which in turn lifts the rear wheel = oversteer you can see it at snetterton on turn 1 in my video if i put a sharp input in I get roll at the front which effects the rear which because its so stiff snapps.... in oppo

Running the fronts stiffer 9 - 8 or even 8 - 8 should help me in this respect... This is what an ARB will do for me..... allow me to run more compliance in the front suss but still get no roll?

The rear always stays flat as a pan cake.... and appears still well damped to me, its just the front thats a problem.

Fast road Ntr's 888's standard ARB for the record!

Thanks for persevering!

Edited by Firthy, 27 September 2012 - 11:44 AM.

[chris_uk]

You cant relay on one componet to do the job another. Ie dont try alter your shocks to act like an arb. Just get an arb. Sure it might help a fraction but everything in the suspension world is a compromise. If you start altering one thing to take up the slack of another your going to be in a world of confusion. I think the key is to be smooth you already know it, allow the weight to transfer smoothly. What springs are you running at the front? What kind of tyre pressures are you running front/rear.

Edited by chris_uk, 27 September 2012 - 11:53 AM.

[Scuffers]

Very interesting post again! that explains a lot of the feedback on here... regarding Mono tube and Twin Tube dampers. (people having trouble setting up the latter for a balance between control and stiffness) I have also driven a car on the latter twin tubes and could feel what the graph shows.


I know what my problem is with my setup now I currently run 10 (from hard) front 8 (from hard rear so rear stiffer) and as soon as i turn in at high speed if I am not super smooth on my input I get a dive of front roll which in turn lifts the rear wheel = oversteer you can see it at snetterton on turn 1 in my video if i put a sharp input in I get roll at the front which effects the rear which because its so stiff snapps.... in oppo

Running the fronts stiffer 9 - 8 or even 8 - 8 should help me in this respect... This is what an ARB will do for me..... allow me to run more compliance in the front suss but still get no roll?

The rear always stays flat as a pan cake.... and appears still well damped to me, its just the front thats a problem.

Fast road Ntr's 888's standard ARB for the record!

Thanks for persevering!

what video?

You cant relay on one componet to do the job another.

Ie dont try alter your shocks to act like an arb. Just get an arb. Sure it might help a fraction but everything in the suspension world is a compromise.

If you start altering one thing to take up the slack of another your going to be in a world of confusion.

I think the key is to be smooth you already know it, allow the weight to transfer smoothly. What springs are you running at the front? What kind of tyre pressures are you running front/rear.

kind of yes, if I am understanding you right.

Like I said before, dampers are not there to hold the car up, that's the job of the springs.
same for the ARB, you cannot make up for lack of ARB with dampers.

on a track car, so far as I have gone to date, I have yet to have too stiff an ARB, and running a siff ARB takes some of the need for high front spring rates away (note I said SOME).

Back to dampers, honestly, if you have twin tube ones, then the only good answer is to bin them.

[Firthy]

Cheers Scuffers,

Yep stiffer ARB it is then... I have Nitron NTR's Fast Road's so 375 lbs/" front, 475 lbs/" rear. (monotubes)

Cliffe's Gaz shocks are also mono tubes not twin tubes like the Golds.

Edited by Firthy, 27 September 2012 - 12:34 PM.

[Firthy]

Sorry forget the video didn't mean to stick that in... as I haven't posted it.

[chris_uk]

I think ur springs are too soft. For track anyway, you should probably look at adding 100lbs to each spring.

[Firthy]

Cheers Guy's thought that might be the case, I am trying to support the car too much with the damper and not enough with the spring! Turning the damping up is only going to make it less compliant and more twitchy on turn apex etc... as it can't deal with the bumps as well because the rebound is so hard.....

Edited by Firthy, 27 September 2012 - 01:14 PM.

[Scuffers]

Cheers Scuffers,

Yep stiffer ARB it is then... I have Nitron NTR's Fast Road's so 375 lbs/" front, 475 lbs/" rear. (monotubes)

Cliffe's Gaz shocks are also mono tubes not twin tubes like the Golds.

you need to decide what you wat the car for, those rates are very low for a track car (VX that is)

as for Gaz, don't care, they are still cheap crap period.

If you know the cost of quality materials and quality machine time, you would understand how it;s impossible to make a decent damper for that kind of cash without cutting a ot of corners. (this does not mean I suscribe to the more ££ the better it must be prinicipal though)

[Firthy]

Yes I hear you on the trade off between road and track... will start with stiffer ARB. If I end up going the way I think I will... aka more of a dedicated track car stiffer springs it is! Cheers for the advice its very much appreciated, and apologies once again for the thread drift Cliffe....

Edited by Firthy, 27 September 2012 - 03:03 PM.

[Scuffers]

Yes I hear you on the trade off between road and track... will start with stiffer ARB.

If end up going the way I think I will... aka more of a dedicated track car stiffer springs it is!

just as a guide, Jamies car is some 800Kg's (no fuel/driver), and has 750lb springs on the front.

[TazN]

I'll confess this is all really way over my head so excuse any obviously wrong lines of thinking. 1/ Are 'recommended' spring rates going to vary between different shocks? ie NTR fast road 375/475 comparred to quantum zero 325/400 that seems like quite a difference if both are aimed at a fast road application. 2/ (been slightly answered by your posts above) I was looking along 400f 525r for a compromise between road and track choice. or am I just better off deciding either way and stick with it instead of trying to get some of both worlds? Some great information I'm sure, even if I dont get half of it

[chris_uk]

I believe that the reason jimmy could get round turn 1 faster than mike is down to the spring rates, mikes are quite soft really (450/550 i think)

[Scuffers]

I'll confess this is all really way over my head so excuse any obviously wrong lines of thinking.

1/ Are 'recommended' spring rates going to vary between different shocks? ie NTR fast road 375/475 comparred to quantum zero 325/400
that seems like quite a difference if both are aimed at a fast road application.

2/ (been slightly answered by your posts above) I was looking along 400f 525r for a compromise between road and track choice.
or am I just better off deciding either way and stick with it instead of trying to get some of both worlds?

Some great information I'm sure, even if I dont get half of it

just to pick up on this, the Quantum Zero's at those rates are for Elise not VX

I have yet to do the numbers for a VX spring rates for the Zero's, but they are likley to be higher (we are also using variable rate springs on them so it's not that stright forward just to compare numbers)