New rear anti roll bar

[Stuntz]

Jedi!

[RMB-Racing]

Well - I think it is great that we have this discussion about handling, when we are changing the suspension on the Q4.

I?m really looking forward to hear about Jim's experience with the new ARB.

Have any of you (Stuntz, Evodelta) experience with, how to remove understeering form the Q4..?

I have the New suspension from D2, and I will almost upgrade to stiffer and thicker ARB both on the front end and back end.

What to do..?

PS. I wouldn't mind heavy oversteering..!

[Evodelta]

Well - I think it is great that we have this discussion about handling, when we are changing the suspension on the Q4.

I?m really looking forward to hear about Jim's experience with the new ARB.

Have any of you (Stuntz, Evodelta) experience with, how to remove understeering form the Q4..?

I have the New suspension from D2, and I will almost upgrade to stiffer and thicker ARB both on the front end and back end.

What to do..?

PS. I wouldn't mind heavy oversteering..!

Well you have to make the front grip better. Adding some more negative camber is the first thing you would do.

[j1v]

a torsen front diff would possibly do some great job too, but bacci romano wants a fortune for them

[jimnielsen]

I have been using -3.5 degrees negative camber ( on the front ) and have just changed it to -4.0. Any opinions on the ideal negative camber for a Q4 track car ( I am using these .. http://www.federaltyres.com.au/ss595rs .. tyres)

J1v - do you have a link to the place where you can get a front 'torsen' diff?

thanks, jimn~

why doesn't pic upload work properly anymore?? at least for me

[Evodelta]

No-one can tell you settings for your car as it is individual in its specification, you have to do your own tests and adjust it accordingly, just guessing is no good. The equipment needed isn't expensive.

[j1v]

J1v - do you have a link to the place where you can get a front 'torsen' diff?

http://www.bacciromano.com/index.php...&cat2=40&mar=5

[j1v]

J1v - do you have a link to the place where you can get a front 'torsen' diff?

http://www.bacciromano.com/index.php...&cat2=40&mar=5

BTW, i've been mistaken, it's not a torsen

[AlfaJack]

why doesn't pic upload work properly anymore?? at least for me

Not sure at the moment Jim, have emailed Steve to ask him if he can query it with the host. For now, another host would be best. My own here is quite easy and quick:

http://www.cloverleaf4.co.uk/upload.php

[jimnielsen]

I am going to give this a try this time...

ignore the caster figures....

[Evodelta]

Based on what? Without testing and getting some results on paper you might aswell open your wallet over the nearest storm drain.....

[jimnielsen]

Based on the fact that I did 65 laps at Winton last month with -3.0 degrees neg camber on the front - and its just not enough. Tire wear is high on the outside working front tire and temp is 20 degrees hotter on the front outside - than the middle and inner. The wheel alignment cost $55 (AUD) that's about 20p in British pounds!

[AlfaJack]

A wheel alignment over here is about ?27!!!

[Evodelta]

Based on the fact that I did 65 laps at Winton last month with -3.0 degrees neg camber on the front - and its just not enough. Tire wear is high on the outside working front tire and temp is 20 degrees hotter on the front outside - than the middle and inner. The wheel alignment cost $55 (AUD) that's about 20p in British pounds!

Ah so you have been testing, so why not say earlier??

Watch out that your toe is set to factory settings because it will give you some duff temp feedback if it isn't - too much toe in gives excessive wear and temp on the outside and vice - versa.

You should really only change one thing at once before testing again so you know exactly what has done what, not easy though I know from experience.
You must have some pretty hard suspension on there to need more than 3' neg - having it too hard at the front will cause understeer, it's very common for people to go too far with spring strengths, harder isn't always better - the strut needs to compress a bit, the more it compresses the more camber you will get.

Another mod I found which worked well was increasing the castor angle on the front struts. I don't know what the Q4 suspension looks like, but I had to re-engineer mine a bit to make it adjustable here.

[Evodelta]

A wheel alignment over here is about ?27!!!

That's too cheap to be true, especially darn Sarf! They charge ?40 cash in the trade for 4 wheel alignment. Is the rear adjustable on a Q4?

You must know somebody.......

[j1v]

Another mod I found which worked well was increasing the castor angle on the front struts. I don't know what the Q4 suspension looks like, but I had to re-engineer mine a bit to make it adjustable here.

Absolutely, more castor gives more dynamic camber.

I found some toe-out work pretty well on FWD cars to cure understeer on a slow track. It does wear the tires too .

I've been always interested in ackerman steering, as it gives dynamic toe-out, but as you know it is pretty hard to make it configurable on a regular car.

[AlfaJack]

That's too cheap to be true, especially darn Sarf! They charge ?40 cash in the trade for 4 wheel alignment. Is the rear adjustable on a Q4?

You must know somebody.......

The rear is not adjustable at all. ?27 was just for the tracking...not sure on 4 wheel alignment jobs.

I know a few people but never well enough to sneak it in for a cheap job at the end of the day..

[wrinx]

?35-40 roujd here too

With four cars in the household I need to find a DIY route!

wrinx

[Evodelta]

Absolutely, more castor gives more dynamic camber.

I found some toe-out work pretty well on FWD cars to cure understeer on a slow track. It does wear the tires too .

I've been always interested in ackerman steering, as it gives dynamic toe-out, but as you know it is pretty hard to make it configurable on a regular car.

Do you think that the suspension arms on the Q4 could be made adjustable for castor?

[Evodelta]

?35-40 roujd here too

With four cars in the household I need to find a DIY route!

wrinx

The proper equipment is quite expensive and DIY routes are quite time consuming, it can be done though as it's only basic geometry. A google search should throw something up, try adding 'string' to your search words.

[wrinx]

Mmm....

http://www.ahspares.co.uk/products/G...TE-MSC217.aspx

http://www.toolsbypost.com/product.php?id=273

Or true DIY:
http://www.beardmorebros.co.uk/websi...o/tracking.htm

wrinx

[j1v]

Do you think that the suspension arms on the Q4 could be made adjustable for castor?

Can't tell, i haven't been looking/thinking on the suspension yet on this car - just a set of yellow konis works pretty fine in the snow and on the street for me at this moment. Some custom arms will surely do the job, but not exactly street legal

[jimnielsen]

Some thoughts on using the 24mm rear anti roll bar...

I used the new 24mm rear anti roll bar that I have had made for the first time (on the racetrack - here at Phillip Island.) Body roll is much more well controlled in all circumstances, and understeer is improved in medium speed and fast corners. All in all it results in faster lap times. Understeer in slow (2nd gear 60kph) corners is still an issue. Unfortunately I have damaged the outside edge of the front tyres.... I am not 100% sure why, but I am going to have to find tyres that are better suited to track use than the ones I am using currently. As you can see in the pic, the tyres are trying to come off the front rim....

jimn~

[j1v]

Some thoughts on using the 24mm rear anti roll bar...

I used the new 24mm rear anti roll bar that I have had made for the first time (on the racetrack - here at Phillip Island.) Body roll is much more well controlled in all circumstances, and understeer is improved in medium speed and fast corners. All in all it results in faster lap times. Understeer in slow (2nd gear 60kph) corners is still an issue. Unfortunately I have damaged the outside edge of the front tyres.... I am not 100% sure why, but I am going to have to find tyres that are better suited to track use than the ones I am using currently. As you can see in the pic, the tyres are trying to come off the front rim....

jimn~

Definitely a problem of tyres, not alignment ... you could easily see that the rim is in a good angle, but the tyre wants to come off ... get some real tyres with hard board.

[#84]

Exactely as J1V says. What tyres do you use? I would say that Michelin and Bridgestone are the best when it comes to the cord structure. Pirelli and Yokohama are probably also good enough. I changed from Kumho to Yokohama and found the tyres to suddenly survive a track day. The drawback is that I had to go from 205/45-16 to 205/50-16 and had to go for the old Yokohama X-pattern tyre which generates a lot of noise.

What front anti-roll bar do you use?

In low speed you are often not so depending on the chassis balance and sometimes turn-in capability could make the difference. I have driven series 1 and 2 cars which feels far less agile than my series 3 car due to the lower steering gear ratio. A slightly stiffer front anti-roll bar increases steering reaction which makes the car get more "thrown" into the corner which in turn transfers more load to the rear wheels.

An interesting comparison (as I see it ) is between my 155 Q4 and a friend's 75 Turbo. The 75 works much better in long corners, in steady state cornering and in high speed cornering. The 155 works better in slow corners, in short/transient corners and in corners which you accelerates out off. If you consider the chassis differences between these two cars (both had the same level of modifications), you might find a key to how to improve low speed cornering.