Damper/shock absorber forces

[Ozone]

Being a suspension engineer I'm a geek when it comes to my AE86 (and S15) suspension.
Does anyone have or know where on the www I can find Force-Velocity curves/data for AE86 dampers/shock absorbers?
I've tried searching on some forums but all I seem to get is "my springs/shocks are better than XXX" but no data.
Any will do for my interest (KYB/Koni/Bilstein etc) although I'm really keen to know for my GReddy Type-S kit as that is what I've got fitted.
I might end up having mine put on a damper dyno if I can't find any information although that is difficult with my car in the UK and me in Japan.
If I do get some info or dyno my parts I'll try to post it with along with some analysis e.g. bounce frequencies, C/Cc etc.

BTW Happy Christmas!

[Ozone]

I'm still interested if anyone has any information.

[Kid Karola]

I have noted the OEM spring settings and damper rates, and TRD damper rates (Tokico and KYB) will dig up what I can for you. (only figures, no graphs) Companys like Koni and Bilstein usually list their damper rates for specific applications - you may need to refer to their catalogues.

Found a little info on the Greddy Type-S dampers (but not much on similar Kei-Office/DG5 or GP Sports, but I'll check in Levin & Trueno Magazine product reviews) Recall spring rates (8k/6k) and 32-way adjustment (5-preset) for Greddy. There's a schematic graph on the brouchure, but for exact figures you might need to opt for the shock dyno
http://www.greddy.com/news/suspension_brochure.pdf

I recently asked HSD distributor for spec on their new AE86 coilover kit (that looks remarkably like a few others now on the market) and got a vague response that didn't really answer the question. Still waiting for clarification...

[NoHachi]

There are some graphs available for the tokico HTS..search around on the interwebs, don't have them handy. They looked pretty good. Would be interested to see the TRD ones.

In the mean time, could you give some details of the model you are using?
I have one wheel and two wheel bump done, but haven't gotten round to doing the roll calculations and pitch calculations. Its weird how the geometry of the rear axle changes between roll and pure bump.

I can take a stab at your results though: ride frequencies near ~3Hz, usually overdamped at approx 1.4~2.0 x Ccrit (most generic stuff uses 200sx shocks unchanged). Basically the no-suspension type of stuff required to run wide rims with 2cm of travel.

[Morten]

I copied these of the internet somewhere a while back. Its the Tocico HTS ones mentioned.

[img name=]http://www.aeu86.org/files/ht/htsadjustmentscale_208.jpg[/img]

[img name=]http://www.aeu86.org/files/ht/hts_graph_main_large_163.jpg[/img]

[Ozone]

Thanks guys for your info.

I'm a suspension engineer and bit of a geek so I've made my own spreadsheets. I've been calculating Roll centre height, load transfer etc. I haven't done any SDoF models though.

With regards to damping forces I'm hoping to calculate %critical damping so I can estimate what springs I can run with my Greddy's - I'm hoping to run softer springs.
I did the same thing with my S15 to spec my own springs rates and I was very happy with the result.

I'll try to get the Tokico HTS info off the graphs and see where they come out.

[Bean]

Ozone Wrote:Thanks guys for your info.
I did the same thing with my S15 to spec my own springs rates and I was very happy with the result.

just curious what (setup) did you end up with as I have an S-body as well?

[NoHachi]

What do you use for cog height? I have the roll centre height for the front but its not much use without the cog height. Also I get into trouble with the rear roll centre: it just moves around so much.
What company do you work for? Been dying to pick the brain of a professional susp.engineer regarding the 86.
So far i've just set the nat.freqs to 2Hz allround and placed the suspension in the middle of its stroke. What are you aiming for? Which shocks? Care to share spreadsheets?

[Ozone]

I work for large Japanese car manufacturer.
I bought my S15 with standard suspension and fitted NISMO springs and dampers. When I returned to the UK the NISMO stuff was far too stiff. I ended up with Standard dampers and custom springs - 26N/mm front springs, 28N/mm rears. Faulker who made them actual made the fronts at 28N/mm which made it understeer but I fitted some PU ARB links which got the balance neutral again. If it wasn't I had a S14 ARB for the front which is slightly smaller.
S15 standard dampers have quite high forces for a standard damper (compared with S14) so can take stiffer springs while still feeling composed and well damped.
I'm not into mega stiff suspension so I'm sure some people would disagree with the above but I think comfort and grip are as important as handling.

Back to AE86!
I'm using a guestimate of 500mm for CoG but haven't done any research as to how accurate it is. As I'm only using for making comparisons, not outright results so it doesn't make a big difference.
I'm only using static Roll Centre. I measured my car up (although quite inaccuratly, I need to remeasure now I have a flat garage floor) and calculated them at 90mm front and 265mm rear.
I bought Greddy Type-S when living in Japan as I got a big discount. With 8kg/mm/6kg/mm springs I've calculated bounce frequency of 2.49hz front and 2.56hz rear. I want to run softer springs but I'm worried my 86 would then be over damped even with the dampers set to minimum - that is why I'm trying to get damper info. Even then I think the Greddys might bottom/top out as the stroke is so short. Anyway I think less than 2Hz would be a good start - 5kg/mm/3.5kg/mm.
When I share any spreadsheets I want to double check I haven't any errors first! I hope in the future to have one big spreadsheet that does everything, at the moment I have a number of smaller spreadsheets. Below is a screen shot of my front suspension geometry calc sheet:

[SekiguchiUeno]

I am not suspension specialist (that does not mean i am not interested in it

I have the same feelings about suspension like you, many peoples use too much rubber and too much springrate and damping force than really needed.

I have some static load data from koni/bilstein/stock
I find it and post it here.

Problem about greddy is very short stroke. I tried 6kg/mm in front and it feels little bit better but there was already preload needed to not bottom out and keep the static heigh in the middle of the stroke. I tried also 3,5kg in the rear but the preload needed was already too much for my taste without that i was always at the bottom of the shock(or better to say on that rubber buffer on the shaft). The shocks alone have from feel much compresion damping force comparing to bilsteins.

For street car i was trying to get 4,5/3,3 kg/mm + stock bilstein shocks, but ended with springs little bit out off the scale. Still think that setup would be great for experienced driving and still be very comfortable, enough stroke etc. I need to order adjustable swaybars and tweak little bit.

I would say 6/5maybe 4,5 can be used on greddy with some preload on the springs. Much less will not work.
But then again greddy with its very short stroke is good for autoX/slaloms events where you dont need bodyroll at all and dont care about stroke.