Tuesday, January 06, 2009 - 07:04 pm, by: Ben Lipman(Ben12a)
I am currently looking at the suspension setup on my track car. I measured the 'eyebrow height' or 'Centre of Wheel to Guard(CWG)' height for all four corners today. The table below is the results with the car empty and with my weight (80kg) in the drivers seat.
front left
front right
rear left
rear right
Empty
336
335
333
328
w/ driver
336
331
332
322
As you can see the drivers(R) side is lower both empty and with driver on board. I was going to adjust it so it is all level, but then I thought maybe it should be done with me sitting in the car. What are peoples thoughts?
The second question is on ride height. My road car is set at the specs recommended by Tein: 360mm front and 340mm rear. Does anyone have any informed opinions or suggestions?
Once I get the ride height sorted it'll go in for a wheel alignment. I intend to speak to the workshop guy about camber/ caster/ toe settings seeing as it is a track only car.
Tuesday, January 06, 2009 - 10:08 pm, by: Andrew Meiers(Acmtt)
Traction tyres did mine. they set the car to level, checked corner weights, realised that there was little to be done to correct the jzz stock balance without major reassignment of components. They checked with me in the driver seat on the scales. They also checked heights from the concrete floor to the sill underside.
Wednesday, January 07, 2009 - 08:34 am, by: Ben Lipman(Ben12a)
I don't know if anyone has corner weight scales in town. This is a mining town. I recently partook in a discussion with several professional mechanics who sincerely believed torque wrenches are a total waste of time...
Are they normal equipment in a tyre/suspension shop? Otherwise I'd have to travel to get a service like that.
Thursday, January 08, 2009 - 07:27 pm, by: Ben Lipman(Ben12a)
Dave,
read the thread above. Thanks for that.
So I get that you have 15kg springs (front I take it?) and a ride height of 360mm(front?) and it handles well?
I have 17kg springs up front, and plan to run 360mm CWG. I also intend to dial in some camber(from reading on here 2.2 degrees is all you can get out of the factory setup) and get the thing properly aligned. Does this sound OK?
Obviously I'll be talking to the alignment guy next week, but you seem to have a good handle on suspension in general, and the Soarer in detail.
Friday, January 09, 2009 - 03:19 pm, by: Dave Cazes(Cazman)
15kg is my street setup, its border line too stiff, but its pretty nice really
360 is all Id run, any lower isnt doing you any favours, especially your roll centre.
2.5 camber is atainable at 240 cwg, but 2-2.2 is all you will get at 360cwg.
Caster is more important, and yours will max at 4 deg ish too.
For any more you need: Option daizin bushes ex USA, $100 ish or something + labour + post, very very good $ upgrade Next option is china arms $400ish but make sure to put me in your will Then Ikeya arms $1200+ gets a abit stupid really.
Use 0 toe up front, or 2 or 3 mm toe out if you want decent turn in, on tight tracks. you wont beleive the differents this will make to turn in.
I have some rear arms being made locally from USA made parts, Namely the rear toe arm and the rear traction rod, these will be rose jointed, easy to adjust (unlike the stock cam bolt setup) they are turnbuckle and should be about $180 per pair of arms. You can get china ones for about $200+ but these are chromolly not cheap rubbish.
Fulcrum also released some rear subframe bushes (not pineaplles, they have been out for a while already) but actual bushes, but think $150-250 depending on what mood im in
basically, at that ride height, you will max out EVERYTHING in your stock setup, and be wanting more after 1 track outing.
Especially since you are running semi slicks, you will be wanting 3+ degrees camber and 5 deg caster for sure.
Its all trial and error really, but I have done a years worth my self and I have managed to redo every single thing in my car about 3 times now.
If you havent got them get some swaybars, custom selby's, not whiteline, the whiteline ones arent big enough really, ok for street but not for track, I cant sell mine, it seems no one wants whiteline bars even.
The other prob is rear wheel travel, swaybars limit it, the prevent droop and cause inlift, I am running long rear shocks and I still get inlift exiting tight corners on the street. In your case HSD are very very short so swaybars wont effect you in this area.
But when your inside wheel comes back down your car will errupt in wheelspin, even in drifting this inst good for balance.
Friday, January 09, 2009 - 04:33 pm, by: Ben Lipman(Ben12a)
I have the Selby adjustable sway bars that were on a group buy last year. I dont have the specs handy, but they are solid, not hollow.
I'll have to talk to you later in the year and maybe get some of this gear from you (I take it you are in the business).
I imagine, after reading this and the first 10 pages of the Gixxer thread, that raising the ride height and getting it all aligned will make a huge difference compared to the last track day.
Monday, January 12, 2009 - 10:08 am, by: Dave Cazes(Cazman)
Selbys are great, what was the group buy? what price if you remember? maybe peter would allow another one that I could organise
The problem in soarers Ben is that the higher you go the worse your alignment is for racing use. 2 things though, the lower you go the more your roll centre and bottom out point is, which is the worst thing you could do to your car, but the lower you go the more caster and camber you gain, so its catch 22.
When you hit the track I suggest you bring a thermometer, not laser one but a probe style one as they are more accurate. jaycar sell them for $40 and it will be your best investment for tuning.
Get a mate or wife to help you too, everytime you pit in, come in as quick as you can without obviously heating the car itself up excessively, temp probe the inside, middle and outer of your tyres tread. Do this as quicly as possible and write all your data down or its useless.
Try to get a helper to do this as you wont have time youself as you will probly be strapped in to your seat.
The main thing to check for is visibly rolled over side walls which suggests either too little camber, or too skinny of a rim, you are using semislicks so you wont get as much roll as others, but you maybe.
If the other temp is alot higher than the middle then you are in trouble and will most likely have to fork out for a decent camber kit from the USA. or a cheap ebay china kit. Be warned though, as the cheap kits really muck witth your geometry and dynamic camber as they only come with adj upper arms, and not lowers like the Ikeya sets.
Monday, January 12, 2009 - 02:28 pm, by: Ben Lipman(Ben12a)
I have just read an old Auto Salon magazine. Now, before the world opens up on me, I don't usually buy magazines that are all style, no substance, BUT it had Khalid's pretty Soarer in it. (soon after the pics were done it was destroyed by vandals.)
Anyway it had a good article about suspension geometry, the effects of lowering too far etc. The diagrams illustrated what I believe Dave was getting at earlier.
In short, as you lower the car the roll centre lowers in relation to the car. Sounds great? Well, no actually. The reason is the centre of gravity(COG) remains in the same spot relative to the car. When you lower the suspension too far, the roll centre gets further and further below the COG actually causing more body roll. The reason we don't really notice is because we generally fit stiffer springs and sway bars at the same time as we lower.
The article goes on to state that you want your line between the two roll centres (or roll axis) to be as close to, or above the COG.
The full article is in issue 54 of AutoSalon magazine. Apologies if I have butchered any of it too badly.
Monday, January 12, 2009 - 02:30 pm, by: Ben Lipman(Ben12a)
Sorry Dave,
I don't remember exactly the details of the group buy, as I was out of the country. Around $500 ish for front and back I believe, and Khalid Swari may have been the guy to organise it.
Wednesday, March 25, 2009 - 01:25 pm, by: Dave Cazes(Cazman)
No more to tell. I know who makes their stock bush kit, but the extra camber kit is not made by energy or fulcrum, so your must order them ex USA really.
I am seeing if fulcrum can make them offset, I know its possible, but if they are they should be steel shelled as well, which would incur extra costs.
Ill let you know, and who wants to be the guniea pig?
Thursday, March 26, 2009 - 07:21 pm, by: Ben Lipman(Ben12a)
the good news is the US is literally printing money, so the US dollar is on the decline. How low will it go? Buggered if I know, but maybe they will get cheaper.