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Re: Koni Racing strut conversion...

Tue May 31, 2016 5:23 am

underscore wrote:I'm assuming Koni shock dynos their dampers?


They wouldn't do it individually with the Red, Sport and FSD lines that's for sure. They would do a couple as part of batch quality control though.
With their more expensive models they may, but the high-end performance guys would have them redyno'ed, and revalved by local tuning shops or in-house anyway.
The thing that does make Koni one of the better low-mid end brands is decent consistency between units and over time. Iv'e seen this mentioned by a few different people that have dyno'ed them.
If i had a couple of extra weeks to spare before i need my car back on the road, i would have tried to get mine dynoed for interest sake. I need to get mine finished & back in the car for this Friday, so i wont have time to dyno them now.
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Re: Koni Racing strut conversion...

Wed Jun 01, 2016 10:06 am

I got the fronts finished this arvo :)

Image

Top adjuster is for rebound, bottom adjuster is for compression.
Image

Will hopefully get the rears finished tomorrow.

Re: Koni Racing strut conversion...

Wed Jun 01, 2016 10:29 am

Any photos of the process yet?
What springs are you running? Helpers too

Re: Koni Racing strut conversion...

Wed Jun 01, 2016 11:00 am

Ill leave the progress photos until later when i do the write-up.

Front springs are 475lb/in (8.5kg/mm).
Rear springs are 450lb/in (8kg/mm).
Helpers are Whiteline something that i dont think are available anymore. Any helper/tender coils will do.

Re: Koni Racing strut conversion...

Wed Jun 01, 2016 8:11 pm

Nice project, I have been looking into a similar Koni race setup but using some old Tein HA strut cases.

I assume you have read http://wilhelmraceworks.com/koni-shock-dynos

The shock dynos and calculation sheets (adjusted for ST185 corner weights) suggest that 8611 race series will be a pretty good match to the GT4 from around 4KG/mm up to around 12KG/mm (from memory). What I really like in comparison to the majority of "adjustable shocks" is that the low speed damping shifts in line with the high speed damping, most BC/Tein etc all seem to lose all semblance of low speed damping as soon as you open the bypass valve needle.

Which model inserts did you go for?
I would be interested in why you chose such stiff rear spring rate in comparison to the front?
I ran through some basic calcs for the standard front and rear anti-roll bars and from memory they were expected to be less than 0.5kg/mm, uprating to whiteline with springs as stiff as most coil-overs use is therefore probably pointless and will go mainly undetected but with standard springs or mildly uprated will provide a big change.

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 2:58 am

This thread is pertinent to my interest.

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 3:52 am

diceman wrote:Nice project, I have been looking into a similar Koni race setup but using some old Tein HA strut cases.


Good idea, i assume they are inverted?

I assume you have read http://wilhelmraceworks.com/koni-shock-dynos
The shock dynos and calculation sheets (adjusted for ST185 corner weights) suggest that 8611 race series will be a pretty good match to the GT4 from around 4KG/mm up to around 12KG/mm (from memory). What I really like in comparison to the majority of "adjustable shocks" is that the low speed damping shifts in line with the high speed damping, most BC/Tein etc all seem to lose all semblance of low speed damping as soon as you open the bypass valve needle.


It's funny, i only found that Wilhelm RaceWorks website in the last few weeks.
Ive been running 1259's in my front stuts for about a year now which have been great (i actually bought the 1259's for a different car about 8yrs ago, but never used them). Seeing that website has just confirmed why they have been working so well.
I have been running KYBs in the rear though, hence this new conversion happening now. The new 1257's are going into the front, and im moving the 1259's into the rear.

I would be interested in why you chose such stiff rear spring rate in comparison to the front?


Spring choice is based on the TTE setup sheet for this car (A. Aghini in the 1994 Corsica WRC round):
Image

There is some awesome old footage of him (and the other two TTE cars) here: https://www.youtube.com/watch?v=IY7WMjkJhh0

I figure choosing a setup myself will never get me close to as well as this car handled. So im just doing what i can to replicate it (within reason of course, mine is still a road car).
... and no, i wont be sharing that TTE setup sheet, sorry :(

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 7:57 am

Interesting.

My Tein Ha are regular configuration (not inverted) unfortunately. The main benefit is that they already have threaded cases and are larger diameter.

It is presently a toss up between sending the cases to Bilstein UK for them to build up some 36mm piston, fixed damping rate, inverted inserts or go for the double adjustable Konis. The Tein cases I had hoped would accomodate a 46mm bilstein piston inverted insert as they are larger diameter than standard struts and at nominally 51mm OD - unfortunately it isn't quite enough over stock diameter to squeeze in the race/rally spec Bilstein and hence I am limited to Bilstein 36mm or Koni inserts. The project has been put on the back burner a little as I stripped the suspension off to measure everything up and found I have TRD Dirt/Rally struts already fitted and the primary issue the poor lowering springs fitted (AVO and circa 45-50mm drop now they have sagged after years - I didn't buy them).

I did run the Koni/Whiteline kit around 15 years ago on my second ST185 and have been through various TRD adjustable setups on ST205 variants and experienced Tein Superstreet also.

IMHO the combination of Eibach springs and Koni single adjustable inserts was about as good as it got with the TRD 4-way adjustable and TRD springs also pretty good on the ST205.

I have spent many an hour trying to match/select spring rate and damping rate and run through a load of calculators which all seemed to suggest that for my purposes (mainly fast road) 5kg/mm and 4-4.5KG/mm front rear respectively were about right if I didn't want to lower it too much. With the current 40-50mm of lowering the car would probably need springs rate of around 8-10KG fornt and 7-8 KG rear which initially seemed more suited to billiard table smooth tracks!

This was until I read this article... http://wrcbehindthestages.blogspot.co.u ... gs-co.html

From this I am inclined to keep to the softer rates and maybe run a little more damping as an initial setting.

Would you be prepared to share any damping rates for your selected spring rate from TTE? I believe at the time they were using Bilstein?

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 11:47 am

celicast184 wrote:Koni's are great Combo 'd with ground control kit. Only thing that turns me away from them is that they are not ride height adjustable without sacrificing shock stroke and preload on the springs. This worries me because as a daily/weekend worrier, there will be lots of stress on the shocks. Especially when the spring basically just floats around if the springs are lowered to get the desired ride height.


This is why helpers are absolutely neccesary on the front with the GC kit. They should be included but they are not. The rears are not bad but the front springs should be alot longer if you lower the car at all with the GC kit.
I actually bought 200lb helper springs for mine to have a progressive spring rate with the 550 springs upfront and help keep the inside tire on the track on corners. I will have to wait till next year to find out if I guessed the setup right. Ground Control recomended 550 front and 350 rear for the bumpy tracks we have around here, still think that might be too stiff (especially after I lighten the car) but we shall see.

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 11:49 am

MWP wrote:I got the fronts finished this arvo :)

Image

Top adjuster is for rebound, bottom adjuster is for compression.
Image

Will hopefully get the rears finished tomorrow.


that is not the Ground Control kit, where is that from?
I was also curious why your rear spring rate is so high.

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 12:22 pm

diceman wrote:My Tein Ha are regular configuration (not inverted) unfortunately. The main benefit is that they already have threaded cases and are larger diameter.


Being able to change the saddle height easily would be a big advantage.

IMHO the combination of Eibach springs and Koni single adjustable inserts was about as good as it got with the TRD 4-way adjustable and TRD springs also pretty good on the ST205.


Ive run King Spring Low's and the normal Koni Sport Yellows on a couple of other cars.
They work quite well for a cheap setup.

I have spent many an hour trying to match/select spring rate and damping rate and run through a load of calculators which all seemed to suggest that for my purposes (mainly fast road) 5kg/mm and 4-4.5KG/mm front rear respectively were about right if I didn't want to lower it too much. With the current 40-50mm of lowering the car would probably need springs rate of around 8-10KG fornt and 7-8 KG rear which initially seemed more suited to billiard table smooth tracks!
This was until I read this article... http://wrcbehindthestages.blogspot.co.u ... gs-co.html
From this I am inclined to keep to the softer rates and maybe run a little more damping as an initial setting.


Wow, 5-4kg springs are soft! Great for comfort, but you cant get a decent low'ish ride height with that rate.
The 185 and 205 WRC cars achieved it by having greatly increased bump travel with raised towers, and top mounted stut tops.

Running that soft, as you mentioned, you also need lots of compression damping, which introduces heat and cavitation problems.
I doubt the 8611 series would be up to the task.

I dont know how you get the idea that the 8611's are ok with 4Kg springs?
Using that spreadsheet shows that even with my 8kg springs the rebound damping will be a bit too high when set on the minimum level.

Would you be prepared to share any damping rates for your selected spring rate from TTE? I believe at the time they were using Bilstein?


The sheet doesnt have any of that information.
It says they are "AM Dynamic - 12 Bars".

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 12:59 pm

TRDTurko wrote:that is not the Ground Control kit, where is that from?
I was also curious why your rear spring rate is so high.


Its an old coilover sleeve kit made by Noltec. I dont think they make them any more.

The sleeve kit im using on the rear which i bought recently is this, but with 8kg springs: http://www.otomoto.com.au/p/9062920/hsd ... it-6k.html
Its a cheap'ish Chinese kit, and the springs are probably crap, but the rest of the kit is decent. I'll just change out the springs for King Springs later.
This is one of the few steel sleeve with locking ring sleeve kits that easy to get.
Im not a fan of alloy sleeves, or grub screw locked rings.

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 1:37 pm

I have spent many an hour trying to match/select spring rate and damping rate and run through a load of calculators which all seemed to suggest that for my purposes (mainly fast road) 5kg/mm and 4-4.5KG/mm front rear respectively were about right if I didn't want to lower it too much. With the current 40-50mm of lowering the car would probably need springs rate of around 8-10KG fornt and 7-8 KG rear which initially seemed more suited to billiard table smooth tracks!
This was until I read this article... http://wrcbehindthestages.blogspot.co.u ... gs-co.html
From this I am inclined to keep to the softer rates and maybe run a little more damping as an initial setting.

Wow, 5-4kg springs are soft! Great for comfort, but you cant get a decent low'ish ride height with that rate.
The 185 and 205 WRC cars achieved it by having greatly increased bump travel with raised towers, and top mounted stut tops.

Running that soft, as you mentioned, you also need lots of compression damping, which introduces heat and cavitation problems.
I doubt the 8611 series would be up to the task.

I dont know how you get the idea that the 8611's are ok with 4Kg springs?
Using that spreadsheet shows that even with my 8kg springs the rebound damping will be a bit too high when set on the minimum level.


2 things
1) I had planned on using the standard single adjustable Koni MR2 insert for the rear on my ST185 as it is closer than the 8611 which as you say are higher damping rates and more suited to higher spring rates (especially on the lighter rear end).
2) With uprated ARB's I expected to get circa 1.5kg/mm plus increase in effective spring rate.

5/4 may be soft for race use but is much more suited to fast road use here in the UK. Having run 4.3/3.9 KG/mm before with circa 25mm drop on my TRD equipped ST205 this is a pretty good compromise. I don't want a large amount of drop as the travel is pretty small to start with for road use. The 5/4 is actually harder than the late TTE spec tarmac spec setup (albeit with v.high quality Ohlins dampers).

I'm interested in why you say the Konis will not be upto the job in handling the heat and possible cavitation? Is this where the larger piston Bilstein can provide will be beneficial?

I've done a fair bit of research in Bilstein damping rates for some known spring rates and they appear to opt for a higher damping rate than that calculator indicates. Even my TRD Dirt/Rally fixed struts with the matching TRD springs have damping rates far higher than that calculator would suggest as ideal. Don't get me started on the BC/Tein excessive damping if plumbed into that calculator and compared to dyno plots - I have no idea how they reached the valving selection or why but it seems flawed.

I don't confess to being an expert by any means and am just starting in suspension calcs but the data I have accumulated suggests the Wilhelm calculator provides quite different ideal damping rates than those developed by the big companies. I suspect the difference is if you are coming at the task purely as a race car on billiard table smooth race tracks where the only item you really need to control is the spring and to hell with body motion but I speculate.

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 1:53 pm

Did you read my Part 1 "Why Im Doing This" paragraph?
My setup is not for a track car. Its a daily driven / hillclimb / tarmac rally car.

Ive had the 8.5kg front and 8kg rear spring in the car for a few months, i actually find it quite soft. I have no problems hitting big potholes.
While running 8.5/8kg i even did a 3000 km (~1800 mile) round trip interstate driving 8hrs/day. It was not uncomfortable at all.

diceman wrote:5/4 may be soft for race use but is much more suited to fast road use here in the UK. Having run 4.3/3.9 KG/mm before with circa 25mm drop on my TRD equipped ST205 this is a pretty good compromise. I don't want a large amount of drop as the travel is pretty small to start with for road use. The 5/4 is actually harder than the late TTE spec tarmac spec setup (albeit with v.high quality Ohlins dampers).


As a general rule you should run 1/3rd droop and 2/3rd's bump travel.
25mm of droop means you only had 75mm travel overall? Surely that cant be the case?

When talking about the 205 TTE WRC cars setup compared to ours, you are comparing apples with oranges.
It's about that time that WRC suspension design took huge leaps forward... we cant begin to compare our setups with those.
A few years earlier, like in the 185 WRC days, they ran more more conventional setups which we can copy/emulate to some useful degree.

I've done a fair bit of research in Bilstein damping rates for some known spring rates and they appear to opt for a higher damping rate than that calculator indicates. Even my TRD Dirt/Rally fixed struts with the matching TRD springs have damping rates far higher than that calculator would suggest as ideal. Don't get me started on the BC/Tein excessive damping if plumbed into that calculator and compared to dyno plots - I have no idea how they reached the valving selection or why but it seems flawed.
I don't confess to being an expert by any means and am just starting in suspension calcs but the data I have accumulated suggests the Wilhelm calculator provides quite different ideal damping rates than those developed by the big companies. I suspect the difference is if you are coming at the task purely as a race car on billiard table smooth race tracks where the only item you really need to control is the spring and to hell with body motion but I speculate.


You keep saying "damping rates"... which damping rates? Compression or rebound?
Rebound damping needs to match the spring. Compression damping can be whatever you like.

Re: Koni Racing strut conversion...

Thu Jun 02, 2016 3:09 pm

I did read your original posts and even watched the videos :-).
Your roads appear far better than ours! I would say those roads have undulations and the odd bit of surface break up. Ours seem to have major grooves from traffic, roads that have dropped in short parts due to partial subsidence of the road sub-layer and large amounts of camber to assist rain run-off (centre whiteline as high point). I've never had the opportunity to drive hard in a firmly sprung GT4 over these roads but much firmer than I am aiming for I would expect would result in large vehicle body movement and wheels leaving contact with the road too much. It would probably be fine on 60mph plus roads. Again I hope to be educated/experience this soon in a friends car.

Sorry for any confusion; I said "drop" not "droop". By this I mean the suspension lowered the static ride height by xx mm over standard springs. I have figures for standard and calculated droop somewhere but I seem to remember that my current (BAD and not my choosing) AVO springs provide around 115mm of droop! this leaves around 40mm of suspension travel until the wheel/tyre has come into contact with the wheel arch and the shortened bump stop is solid and compressed. Given that we only start off with around 140-150mm of suspension travel we need around 50mm of droop according to the 1/3 and 2/3 guide suggested (which I have also read before) and aligns with a circa 8kg/mm spring at the front (without any helper or preload) and would give around 100mm of bump travel but only if you run at standard ride height otherwise you will be reducing the available bump travel. At this point you have 2 options as far as I can ascertain: -
1) run the stiffer springs at circa 8-10KG/mm and lower the vehicle a fair bit (say 40-50mm) in the knowledge that the stiffer spring will require less suspension travel.
2) run the softer spring at circa 5kg/mm and don't lower the vehicle as much (say 15-25). Also don't suffer as much from bump steer in this region.

I'd guess there is merit in both approaches depending on application.

From your writings it sounds like you have read similar sources as myself when endeavouring to select/fine tune spring/damping rates. These seem to be loose guides and far from precise. My concerns have been that all full suspension kits (spring & shock) I have reviewed so far have been way off the numbers from the guides I have read, why I have yet to establish. In particular the commonly reported "Rebound damping needs to match the spring. Ideal compression damping is determined by vehicle weight" seems massively simplistic and bears little resemblence to the shock dynos I have reviewed.

Hence - I keep saying damping rates = compression & rebound as I am not convinced as yet to the accuracy of the sweeping statements that are banded about.

Please don't take my posts as argumentative, far from it. I am merely trying to ascertain the truthes. If we can calculate that Tein/BC/Bilstein/KYB/TRD are all doing differently to the ideal damping calculation (some are miles out) then to me it suggests that the calculation is flawed or there are different requirements.

I'm very interested in to why you feel the Koni 8611 will not be upto the job with respect to the heat and cavitation, again this isn't argumentative but hopefully your experience or findings may save me from making the wrong choice.
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