Double adjustable dampers

[Al Weyman]

OK guys, for the first time I have splashed out and got some double adjustable dampers fitted (rears), anyone got a ball park start point i.e the relation to bump to rebound figure I should set these at as it will be a baptism of fire Sunday with no time for testing.

[Notso Swift]

Don't know how many sessions you get to fine tune, but without being flippant I would start in the middle!

[Al Weyman]

Yeah I was going to do that but someone else reconed set the bounce lowish and the rebound about a third higher, trouble with this kit you buy it and if you don't know how to set it up you may as well leave it in the box. Just thought someone may have had some experience with these. Ithink I will try it one third on the bounce and two thirds on the rebound and take it from there, and we don't get any chance to alter things really.

[Notso Swift]

The problem with 1/3, 2/3 is that the graph shapes may be totally different, indeed the manufacturer may have designed the system so that the zero position is what they recommend and adjustment is designed to compensate for wear (aka Koni's orginal idea) or mid point is what you run normally, with fine tune either way.

Here are my rears (on a light 4WD, like the '80's Mazda 323)
Speed (Metre/sec) 0.13 0.26 0.39 0.52
Force in Nm
Rebound - Min 980 1260 2300 2800
Bump - Min 200 480 770 1000
Rebound - Max 1176 1512 2760 3360
Bump - Max 240 576 924 1200
4 positions for Rebound and 24 positions for Bump
(Note,This ramping up is typical of a rally car, which my car use to be. with a race car they would normall be reverse in shape, coming on quckly and leveling of at higher speed)
So where do I start, well may manufacturer gave me some initial places to start, based on my application, and I went from there, refining it with each run and each circuit (based on how you run the ripple strips, and I tend to use them a bit)

Usally the shocks are the last thing you touch for fine tunig, springs and anti-roll bars have more effect on the dynamics, but if you are like me you work on the basis 1 set of springs, 1 roll bar 1, shock, if I get better shocks I can cover not having enough springs!

[Al Weyman]

Yes i see what you mean, they do suggest 1/3rd for the start point on their single adjusters but no advise on the double adjusters which has thrown me a bit, I asked the supplier for a ball park figure and he has ignored me. These are American QA1's incidently.

[GordonG]

Ideally you could take the old and new dampers to someone with a shock dyno and find the adjustment on the new dampers that most lcosely matches the old - as good a starting point as any, and you can twiddle from there.

Failing that you could try judging by hand - I actually made up a simple "see saw" arrangement for balancing shocks side to side on the car - clamp the bottom of 2 shocks in a vice, with a bar between the tops able to pivot in the middle, then pump it up and down and adjust till you get the bar to stay more or less horizontal.

Now, whether the forces and velocities you are able to impart with your puny frame (I've never met or seen you Al, but I'm betting compared to those tanks you throw around you're puny!) is another matter, but as you say the alternative is a wild guess.

Or you could leave the old shocks in place until you can get some proper testing in. Nah, I wouldnt either.

G

[greenamex2]

Initially go lighter rather than heavier on the bump, probably less of a problem on your 'manly' vehicles but on lighter cars things can go horribly wrong very quickly with excessive bump settings, especially at the rear.

I'd do something really unscientific like set them so they 'feel' like the old ones when you push the rod in and out, then up the rebound a couple of clicks and have a suitably trained volunteer in the pits for practice to fiddle with.

If it's a local circuit, I'm not racing (with the way things are going is a distinct possibility, don't ask!!!!), you supply tickets/breakfast/lunch and you have nobody better I'd happily help.

[Rubinho]

Originally Posted by Denis Bassom

...have a suitably trained volunteer in the pits for practice to fiddle with.

[Al Weyman]

Ideally you could take the old and new dampers to someone with a shock dyno and find the adjustment on the new dampers that most lcosely matches the old - as good a starting point as any, and you can twiddle from there.

If you see the way the rear of my car was hoping about and corkscrewing you would realise I want to get as far away from the orginal as possible! They were in fact standard IROC Bilstiens and standard springs and although the IROC is a performance option our American cousins like their comforts so lets say it was a tad on the soft side:-)

I am running it a bit higher as well as the spring/shocker package is a tad tall but should settle but doing a bit of research I may well have had it too low before causing the wishbone angles and roll centres to go to pot as I drove one of these cars on the road and I swear it handled better than mine was, heres hoping. The whole set up including the rose jointed Torque arm, LC Arms, Panard rod and now the coil over conversion have all come from Steve Spohn Racing and they seem to be highly rated over in the good old US of A.

All the tickets have gone Dennis but come down to Brands on Sunday as it looks a cracking weekend's racing. I might stretch to a cup of tea!

[greenamex2]

Originally Posted by Al Weyman

All the tickets have gone Dennis but come down to Brands on Sunday as it looks a cracking weekend's racing. I might stretch to a cup of tea!

Sorry, at Cadwell on Sunday. Providing nothing else goes wrong!

[Al Weyman]

Good luck Dennis, give my regards to Gerry, he will be out this time.

[Chris Y]

Off topic perhaps, but just what *was* going on between those two Pug drivers, the Honda chap (Saunders) and Mr. Cain at Cadwell? It looked like there was going to be a punch up at one stage...

[Al Weyman]

I can't say too much on air but Gerry is not happy with some of the driving tatics displayed especially the weaving.

[greenamex2]

I have some photographic evidence from both my mum and my wifes cameras.

In the pictures I have Gerry was being very sensible, the others were being varying degrees of less so. Without knowing what happened pior to the sequence I wouldn't like to point fingers but from what I do have there was 'blaim' in all directions. Very much a 'red mist' in an inadvisable place racing incident.

The fact the Gerry walked away with the win after the others all 'fell over each other' speaks volumes for experience and patience over determination.

All the drivers were speaking to each other afterwards so there was no lasting harm done.

And yes, just about everything did go wrong for me, talk about inviting bad luck with my previous comment!!!

Still had a good clean race at the back.

[Al Weyman]

Trouble is if things don't get nipped in the bud they invariable end in tears and the championship looses more drivers.

[Chris Y]

I have some photographic evidence too, which is why I was confused at Gerry being involved in the post-race 'discussions', as it seemed he was very much not involved in the on-track incidents.

[greenamex2]

I think he was annoyed at some drivers possibly making the series look bad.

[Al Weyman]

I think a drivers wife started having a shout at him after the race and that has I am afraid really got him down apart from the rest of the on track antics.

Sadly, (and you will all find out tomorrow) this has had further unfortunate ramifications but I am not at liberty to divulge more until all the interested parties have been informed. There is not much thanks for running these clubs as I found out after 10 years of doing just that.

[norman-normal]

Al I called Summit about your QA1 rears. I assumed your camaro is a pre '69. The guy I talked to was very help-full,,,about drag racing. I told him it was for Brands Hatch road racing; he said "start in the middle and work from there"

About what I expected, but I thought I'd try.

[Al Weyman]

Thats jolly decent of you Norman thanks, its actually an 87 3rd gen IROC. I opted for 1/3rd 2/3rds as an initial setting and the corner weights were not set up but it was a big improvement and I did manage to win my class despite being down on power as I had to strangle the exhasut with a Supertrapp for the race, so a good starting point. Trouble with me is I tend to adabt to what is underneath me and not that sensitive to little changes so it may be hard for me to know which way to go with these. I think the rebound may have been too high as I did get a rear brake lock once or twice, I will try that half way position.

[norman-normal]

Happy to help, I have an account there and it cost me nothing to call, just let me know if there is something I can do.