bigger rear sway bar or droop limiters aka chains - integra

[da9jeff]

Just wondering if limiting the rear wheel droop length with chains or cables will have the same effect as fitting a thicker rear anti rollbar?

The intended out come is that I want the car to have less power understeer.

My understanding is that a bigger rear bar (or any rear roll bar) wants to lift the unloaded wheel, thus lowering that wheels effective spring rate and achieving less body roll as there is less "spring" holding that side of the car up. If thats all that is happening, then could I just install some chains or cables that will allow, say 1 inch of droop before it stops the suspension travel?

Also, someone suggested that I disconect the front sway bar to achieve the roll balance that I want. I disagreed with that as I would have thought it would be better to have more total roll control with the correct rates front and rear, than have the correct rate ratio (front/rear) with less overall roll rate. Is this correct?

Cheers,
Jeff

[Uncle Arthur]

Droop limiters don't do anything to counter body roll so if roll is the problem then changes to your spring/ ARB rates are the answer, with dampers relevant to transitional roll. With a front wheel driver you need to transfer as much of the anti roll duties to the rear as is possible, if this results in the picking up of an inside rear wheel on occasions then so be it.

Generally speaking, with FWD soft front, hard rear.

[da9jeff]

thanks richard. so why do people fit limiters? the one that sticks out is that white/blue IPRA laser in race magazine.

also in regards to my other thread about 225 tyres on 7 inch rims, the guy I bought them off (class winning targa tas S1/2 RX7 13BT) ran them on 7's and has just purchased a set of yokos in 225 to go on the 7's. Thats not to say its ideal, just that it does work.

Thanks,
Jeff

[charged]

Jeff most people run the limiters to help with spring retention,

[Gammaboy]

Short, stiff springs tend to fall outwhen the suspension goes into droop, so the options are limit straps or internally droop limiting the shocks...
A guy i know off another board experimented with a droop limiter on the back of his Alfa (ie it kept the springs quite close to ride height when the car was off the ground, there was a fair bit of compression), the thing developed a habit of swapping ends under heavy brakes and snap oversteer in mid corner. Removed it and it all went back to normal.

[da9jeff]

ahhh ok. after thinking it through in my noggin i have a better idea of how arb's work and why chains wouldn't do what i want :)

cheers,
Jeff

ps whats with the charged then gammaboy double team in both my threads??:D

[xbgs351]

Short, stiff springs tend to fall outwhen the suspension goes into droop, so the options are limit straps or internally droop limiting the shocks...
A guy i know off another board experimented with a droop limiter on the back of his Alfa (ie it kept the springs quite close to ride height when the car was off the ground, there was a fair bit of compression), the thing developed a habit of swapping ends under heavy brakes and snap oversteer in mid corner. Removed it and it all went back to normal.

Front wheel drive car?

[Gammaboy]

Nope, Alfetta platform car.

[Uncle Arthur]

If some are using droop limiters merely to stop the springs coming loose then tender springs can be used for that, a better solution IMHO.

There is some theory for limiting droop on RWD cars that is to do with handling, I was thinking about doing it on the front of the Z but decided it would be inappropriate when driving the car on the road.

[xbgs351]

Nope, Alfetta platform car.

Well that was never going to work.

[xbgs351]

Limiting droop on the front of a rear wheel dive can work. Just look at the Gould in Race magazine for instance. Limiting droop can increase weight transfer at the front by adding the unsprung mass of the inside wheel/hub/etc to the sprung mass.

[morerevsm3]

you better get it sorted Jeff...I changed springs and fitted camber plates and LSD to the E30 and it is 4.5 seconds a lap faster at Winton now...

[da9jeff]

assuming i can get some 15" wheels, Ive now got shagged out re555's so beat THAT!!1

Ill prob just fit a whitline rear sway before the next pooper sprint, You going?

Anyway, If you beat me I'll just take the bit of wood out from under the throttle - easy......:D

Also, you doing the Ledgend of the Lakes in Nov? I am. should only be a couple hours drive for you. I think entries are full now tho, Its a pretty popular event.

[morerevsm3]

I am in Winton 6 hour the weekend of next supersprint, not doing lakes, will do Ararat hillclimb in november though

[Gammaboy]

Limiting droop on the front of a rear wheel dive can work. Just look at the Gould in Race magazine for instance. Limiting droop can increase weight transfer at the front by adding the unsprung mass of the inside wheel/hub/etc to the sprung mass.
Yeah, and they look ace carrying the inside front wheel :D

http://photos23.flickr.com/34692982_2c2e891b1f.jpg

[Lonx]

what bars do you currently run front & rear?

I'd definitely look at the fattest rear bar whiteline can give you before worrying about chains... I've only a little Nissan Exa, but with koni yellow's & king springs all round (was going to go Eibach but the king's were a little stiffer and suited the yellows better) - it was alright until I fitted the 27mm solid rear swaybar (whiteline). The result was kinda lucky for me as the setup allows me to play under/oversteer with the touch of throttle, exactly how I wanted it to end up. First time out I turned in quite heavy and found the rear wanted to come right around, but a little adjustment to my driving and it ended up being very predictable & much better grip when putting the power back on mid-corner.

[da9jeff]

unlike some bmw's i run with :D my car is mechanically stock, just striped interior and other bits moved around, oh and some pedder shocks/springs from when it was my road car. It handles pretty well now just that under power it pushes alot. The worst being turn 1 and northern hairpin at mallala- i know its FWD but im sure theres heaps more to be had, just that I want to spend the least possible ;) The whitline bar is like $220 so ill order that asap unless anyone know if they can be made cheaper at an industrial spring shop?

If someone wants to give me some fulltime work for 6 months, i'll promise to get this fucker sorted before i head off to wagga ;)

[da9jeff]

I am in Winton 6 hour the weekend of next supersprint, not doing lakes, will do Ararat hillclimb in november though

oh well, anyway I got the entry for ararat but i think my bank card would crap its pants seeing as im only doing cash jobs atm. Wouldn't have any pics of the track would you?

Cheers,
Jeff

[Tripper]

If some are using droop limiters merely to stop the springs coming loose then tender springs can be used for that, a better solution IMHO.


Wouldn't using a shorter shock so it retains the spring under full droop be a better answer ?

[da9jeff]

will bottoming out shocks out regularly (ie full droop) damage them? does it depend on the shock?

[charged]

Your topping out the shock when it goes to full droop not bottoming, bottoming is worse as it fucks the bump valve at the bottom.

http://www.minimania.com/images/webstuff/keith/Damper-3.gif

[Gammaboy]

Wouldn't using a shorter shock so it retains the spring under full droop be a better answer ?

Yep, thats why I had Heasmans install 40mm droop limiters in the fronts of my XY's billys.

[Lonx]

I'm far from a suspension specialist and most who replied probably have a better idea than me, but I'd go for keeping the shock in full range if possible and sort it out with a swaybar before trying to limit travel of anything else because I think you'll have a better balance overall.

Plus if its near stock as far as power goes then u're less likely to have her up on two wheels as much (not taking your driving skill/method into the mix of course). I mainly replied because I was honestly amazed at how much of an improvement the tighter rear bar made - was the first time where I needed to consider counter steering on a regular basis if I went in too hot.

[Uncle Arthur]

I'd be wary about droop limiting the driven wheels because you want both of them on the ground at all times. For the same reason, grip, they need to be still under spring pressure in droop, not just hanging down due to gravity only.

But for the undriven wheels there is an argument that if they are not droop limited then they should just hang down due to gravity only when in droop. Otherwise the inside wheel's spring may add to the roll forces. Never seen that point mentioned in any book but it makes sense to me and is the way the Z has been set up. Ooops, that was supposed to be a secret :)

[xbgs351]

This subject is discussed in Appendix A of Brabham+Ralt+Honda, The Ron Tauranac Story.

I think Carroll Smith also discusses this topic in some of his books.

[hrd]

Just wondering if limiting the rear wheel droop length with chains or cables will have the same effect as fitting a thicker rear anti rollbar?

The intended out come is that I want the car to have less power understeer.

My understanding is that a bigger rear bar (or any rear roll bar) wants to lift the unloaded wheel, thus lowering that wheels effective spring rate and achieving less body roll as there is less "spring" holding that side of the car up. If thats all that is happening, then could I just install some chains or cables that will allow, say 1 inch of droop before it stops the suspension travel?

Also, someone suggested that I disconect the front sway bar to achieve the roll balance that I want. I disagreed with that as I would have thought it would be better to have more total roll control with the correct rates front and rear, than have the correct rate ratio (front/rear) with less overall roll rate. Is this correct?

Cheers,
Jeff

here's how it works:

a swaybar increases the effective spring rate on the outside wheel when cornering, and has an equal and opposite effect on the inside wheel - ie it applies the same force upwards on the inside wheel as it applies downwards on the outside. But the thing that's changing the handling balance is the increased spring rate on the outside wheel, not limiting the droop on the inside rear.

on a FWD, a larger rear bar will have 2 effects:
1. change in balance - less understeer/more oversteer than you currently have
2. keep more weight on the inside front wheel when cornering, improving corner exit traction.

removing the front bar will only do one of those 2 things - the change in handling balance. It will have little effect in keeping more weight on the inside front wheel as what you make up for in removing the upward force that was being applied to the inside front will be somewhat offset by the increaded body roll.

you could remove the front bar and compensate for the change in roll resistance with heavier front springs, but this could make the car more skittish and reduce traction over bumps and may also require different shock valving, depending of course on your current spring rates.

a larger rear bar is a much better solution most of the time for a FWD, which is why its so common.

[da9jeff]

cool, thats a great post.

dont mind me, I just like to reinvent the wheel to save $200 :)

[morerevsm3]

oh well, anyway I got the entry for ararat but i think my bank card would crap its pants seeing as im only doing cash jobs atm. Wouldn't have any pics of the track would you?

Cheers,
Jeff

one tree hill road

http://maps.google.com.au/maps?f=q&hl=en&geocode=&q=one+tree+hill+road,+ararat,+victoria&sll=-25.335448,135.745076&sspn=52.088211,71.71875&ie=UTF8&ll=-37.2649,142.885308&spn=0.017658,0.038452&t=h&z=15&iwloc=addr

[morerevsm3]

crappy vid of road, holding camera and driving towards the sun late afternoon causes camera to struggle with colour balance, but you get the idea.

http://www.youtube.com/watch?v=3qXCzhwOy94

hill is steep, think mt panorama terrain, looking from the top-
http://i5.photobucket.com/albums/y171/morerevsm3/FILE0004.jpg

[da9jeff]

cool, thanks for that. I'll cautiously say that i'll do it next year/when they run it next. Is the E30 your daily drive?

Speaking of mt panorama, im leaving 3am tues morning. Can't Wait!!

Cheers,
Jeff

[morerevsm3]

Is the E30 your daily drive? Cheers,
Jeff
no, first time its been on the road since about 2 weeks after I bought it, the M3 is my daily, but had the diff out fitting new LSD clutches as the splines were stripped, also fitted DBA 4000 rotors and Ferodo DS3000 pads ready for Phillip Island next saturday, should be quicker next time at mallala with an LSD that works too...

[da9jeff]

when you coming over to mallala next?