Suspension debate ? Kw V2's , bc racing coilovers , cup shocks with uprated springs

[finch wxm]

I currently have KW V2's fitted on my red track car , has anyone gone from these to a pure track car set up on BC racing coilovers ?

If i did this then the V2'S would go on my other clio.

My white clio shocks are non cup so original plan was to buy cup shocks front and rear and maybe some grams springs as i have apex ones currently and dont know what they are like , white clio is mainly for b road blasting .

What are peoples experiences with these various shocks ?

 

[VenomUK]

AST all the way. I was sceptical about the hype but the hype is real.

 

[R29TJR]

AST all the way. I was sceptical about the hype but the hype is real.

I've only ever run OEM, GAZ GHA's and AST4100's and I must say the AST's have been amazing. So much more comfortable on the road than the GAZ and I've been able to get them perfect for every occasion.

 

[banhama]

I have the BC DS on my 182 track/race car, and I am very pleased with them.
I specified 8kg/mm springs all round.
Many would say that's a bit soft for the rear, but that's based on tyres of equal grip all round.
I tend to put harder, less grippy tyres on the rear so the softer spring compensates, and then you can fine tune on the dampers.

I haven't tried AST's and I am sure that they are a superior product, or at least should be for the price!

My experience of different coil-overs comes from a different track car (Impreza) where I tried Tein, Cusco, HKS, BC and finally Nitron, (very expensive).
I got my best lap time around my favourite circuit, Lydden Hill, on the BC's, hence my choice of BC's for the Clio. Once again on springs slightly softer than the race gurus would recommend.
Tein were good but weak. HKS were horrible but had too hard spring rate to give fair comment. BS external reservoir were great, but I punctured a reservoir in an accident. Cusco second hand replacements were decent. I then went all 'throw everything at the car' with 3-way adjustable Nitrons, and still couldn't beat my best time on the BC's. Although it's likely by this point I'd reached the limit of my ability whatever magic components I chucked at the car )

I would rate BC's as great value for money for a regular track day and race car.
If you're throwing everything at the car I'm sure AST's would be the choice.

Just don't forget whatever make you decide on you can choose the spring rates front and rears.
Getting that right for your application is possibly more important than the make.

Good luck

 

[finch wxm]

AST all the way. I was sceptical about the hype but the hype is real.

They should be the price if them 😜

 

[VenomUK]

They should be the price if them 😜

If you can grab a used set with history then you’re winning

 

[gambit]

BC DS coilovers, as i dont think youd find a better bang for buck setup. After that your looking at 1% gains in concert with driver skill.

 

[finch wxm]

I have the BC DS on my 182 track/race car, and I am very pleased with them.
I specified 8kg/mm springs all round.
Many would say that's a bit soft for the rear, but that's based on tyres of equal grip all round.
I tend to put harder, less grippy tyres on the rear so the softer spring compensates, and then you can fine tune on the dampers.

I haven't tried AST's and I am sure that they are a superior product, or at least should be for the price!

My experience of different coil-overs comes from a different track car (Impreza) where I tried Tein, Cusco, HKS, BC and finally Nitron, (very expensive).
I got my best lap time around my favourite circuit, Lydden Hill, on the BC's, hence my choice of BC's for the Clio. Once again on springs slightly softer than the race gurus would recommend.
Tein were good but weak. HKS were horrible but had too hard spring rate to give fair comment. BS external reservoir were great, but I punctured a reservoir in an accident. Cusco second hand replacements were decent. I then went all 'throw everything at the car' with 3-way adjustable Nitrons, and still couldn't beat my best time on the BC's. Although it's likely by this point I'd reached the limit of my ability whatever magic components I chucked at the car )

I would rate BC's as great value for money for a regular track day and race car.
If you're throwing everything at the car I'm sure AST's would be the choice.

Just don't forget whatever make you decide on you can choose the spring rates front and rears.
Getting that right for your application is possibly more important than the make.

Good luck

Yeah i dont want to put 2k into suspension for the amount of use it will get !

If you can grab a used set with history then you’re winning

Every pair ive seen look like theyve been in the sea and need rebuilding and still well over 1k

 

[Kev@KAM]

Its a balancing act. If you are racing or seriously using the car 10 or so times a year on track then the AST may work out reasonably good value. Just remember to factor in rebuilding and servicing costs.
I run BC's on my Toyota and its great for the money and is a balanced cost for what I use it for. The BC's on the Clio cannot be done with different spring rates on the back but you can get some adjustability with an ARB should you want. However 99% of my customers really are not fussed about a minor drop in performance compared to an expensive race brand. The BC is probably the most popular Clio kit we've ever sold too so its well tried and tested.
Repair costs - they dont rebuild but replace so its a brand new unit each time. Currently £110 for the Ds series inserts each. We dont deal with many issues yet though.

 

[banhama]

The BC's on the Clio cannot be done with different spring rates on the back but you can get some adjustability with an ARB should you want.

I must have been mistaken about choosing the rear spring rate, as I got the kit from KAM, and yes of course there is only the 8Kg rear option.

I guess it was the fronts I wimped out of going hard. Probably due to previous bad experience with over-hard fronts not allowing weight transfer under braking, and compromising both the braking and turn in. Bloody awful feeling tiptoeing around being overtaken by all and sundry!

Why is there no option for spring rate on the rear?
I guess it's because the rear BC isn't a coil-over, rather a replacement adjustable damper and independent spring?
I believe the effect of the spring rate on the Clio 'torsion beam-spring-damper' arrangement is very different to the effect of the spring rate on a full coil-over with independent suspension, BUT I would love to know why!

If you have the time could you give some insight please.
Say for example I got some 10kg/mm springs made for the rear, alongside the BC DS dampers. How much of a stupid idea would that be?

There is a practical reason for asking. Even running less grippy rear tyres at a high pressure, with the rear dampers full hard and the fronts full soft..... so everything trying to induce a loose back end..........I still find once everything gets up to temperature the rear still grips a bit too much to rotate the car as I would like in the tighter corners.
Stiffer rear springs sound like a simple solution, but maybe not with the torsion beam set up?

 

[JimF]

I fitted new Cup shocks with the current Apex lowering springs I had. Planned to replace them but after I’d stripped the car they performed a lot better. Before the car was stripped the Apex springs weren’t great and I understood the criticisms. But with less weight in the rear they behaved better. Perhaps that was the new shocks too. Or maybe I imagined it.
Either way I’ve no complaints. That’s on a road/track car too but I’m no Senna.

 

[Greeny.]

I run BC Racing BR's with 7Kg front & 8Kg rear springs, love them for the price I paid when I purchased them a good 6 years ago, they have covered all of 4k miles in that time, either driving to track or on track and still look brilliant. As said above, cant beat them for the price, obviously the AST's are better but they are double the price, for me who only does 3 or 4 trackdays a year, they are a perfect balance of price to performance.

 

[Greeny.]

I fitted new Cup shocks with the current Apex lowering springs I had. Planned to replace them but after I’d stripped the car they performed a lot better. Before the car was stripped the Apex springs weren’t great and I understood the criticisms. But with less weight in the rear they behaved better. Perhaps that was the new shocks too. Or maybe I imagined it.
Either way I’ve no complaints. That’s on a road/track car too but I’m no Senna.

These are the worst springs ive ever used lol, had a couple of sets over the years, ok for cheap lows for driving around Tesco car park but thats about it imo, your rear end must be seriously high using these with a stripped rear end, if not they must have sagged/snapped over time

 

[finch wxm]

These are the worst springs ive ever used lol, had a couple of sets over the years, ok for cheap lows for driving around Tesco car park but thats about it imo, your rear end must be seriously high using these with a stripped rear end, if not they must have sagged/snapped over time

Ive got apex springs currently on my stripped white build and its like a 4x4 😂

 

[Greeny.]

Ive got apex springs currently on my stripped white build and its like a 4x4 😂

Wouldnt expect anything less! haha

 

[finch wxm]

Yeah just got to weigh up if its worth me going from my KW V2's to the BC racing , i was going to look if i could get a harder spring for the v2's as i think others have done this in the past

 

[finch wxm]

I might put the KW on the white clio instead of buying new cup shocks and a set of springs and get a set of bc racing coilovers with 9kg or 10kg fronts as its a pure track car 🤔

 

[Kev@KAM]

I must have been mistaken about choosing the rear spring rate, as I got the kit from KAM, and yes of course there is only the 8Kg rear option.

I guess it was the fronts I wimped out of going hard. Probably due to previous bad experience with over-hard fronts not allowing weight transfer under braking, and compromising both the braking and turn in. Bloody awful feeling tiptoeing around being overtaken by all and sundry!

Why is there no option for spring rate on the rear?
I guess it's because the rear BC isn't a coil-over, rather a replacement adjustable damper and independent spring?
I believe the effect of the spring rate on the Clio 'torsion beam-spring-damper' arrangement is very different to the effect of the spring rate on a full coil-over with independent suspension, BUT I would love to know why!

If you have the time could you give some insight please.
Say for example I got some 10kg/mm springs made for the rear, alongside the BC DS dampers. How much of a stupid idea would that be?

There is a practical reason for asking. Even running less grippy rear tyres at a high pressure, with the rear dampers full hard and the fronts full soft..... so everything trying to induce a loose back end..........I still find once everything gets up to temperature the rear still grips a bit too much to rotate the car as I would like in the tighter corners.
Stiffer rear springs sound like a simple solution, but maybe not with the torsion beam set up?

Theres two issues. The spring is custom wound so could only be used on that kit - if they dont think it will eb popular enough its not worth the production run

Arguably the larger issue. When increasing spring poundage in the standard location the spring will resist the weight of the car more. This means its harder to get a low ride height without shortening the spring and then having issues like the spring coming unseated when the car is off the ground.

 

[plenty]

I still find once everything gets up to temperature the rear still grips a bit too much to rotate the car as I would like in the tighter corners.

Try increasing rear tyre pressures.

 

[banhama]

Theres two issues. The spring is custom wound so could only be used on that kit - if they dont think it will eb popular enough its not worth the production run

Arguably the larger issue. When increasing spring poundage in the standard location the spring will resist the weight of the car more. This means its harder to get a low ride height without shortening the spring and then having issues like the spring coming unseated when the car is off the ground.

Many thanks for the explanation, that all makes sense.
I guess you have to go to full coil-overs on the rear to play with spring rates.

I don't think I'll be touching the suspension after this Saturday's outing anyway, the car was almost perfect!

I had part worn slicks on the front and used r888rs on the rear.
I also softened the dampers all round as I hadn't tried this combination before.
There was just enough slip in the rear under trail braking to rotate the car without fearing 'sideways moment'
With the gripper LSD there was never any lack of traction.
Almost immediately knocked a second off the best lap time I'd achieved in over a thousand laps with all variety of semi-slicks.

It was also very evident when the slicks started to give up, but nothing snappy just more and more understeer.

So another plus for the BC DS 8kg/8kg. They work really well with slicks on the front

 

[Ph1 Tom]

IIRC @frayz has good experience of V2s

 

[frayz]

IIRC @frayz has good experience of V2s

Had KW Clubsports on the Impreza which were superb, but quite a different damper to a V2. Very well made though, id be happy with KW products again and would probably be my go to for the Clio if they still made them for our platform.

 

[finch wxm]

What valving would people go for on th BC racing coilovers , 10/10 valving and 8kg springs or do i need stiffer ? Pure track car running slicks and semi slicks

 

[JamesBryan]

What valving would people go for on th BC racing coilovers , 10/10 valving and 8kg springs or do i need stiffer ? Pure track car running slicks and semi slicks

10kg front/8kg rear.

 

[finch wxm]

10kg front/8kg rear.

So 10/10 valving and 10kg fronts , 8kg rear springs ?

 

[JamesBryan]

So 10/10 valving and 10kg fronts , 8kg rear springs ?

Not sure what you mean by 10/10 valving.

The valving isn't adjustable it comes set for whichever spring rate you order.

 

[-Jamie-]

Not sure what you mean by 10/10 valving.

The valving isn't adjustable it comes set for whichever spring rate you order.

You can spec the dampers as well as springs in 2kg increments

 

[JamesBryan]

You can spec the dampers as well as springs in 2kg increments

Didn't know that.

Spec them to what exactly?

Doesn't appear to be an option on KAM Racing.

 

[-Jamie-]

Didn't know that.

Spec them to what exactly?

Doesn't appear to be an option on KAM Racing.

The dampers are rated the same as the springs so you can go for a 10k damper with an 8k spring for example. Dampers good for 2kg either way for spring rates though

I only know this as I spoke to BC when wanting to spec up the ones on the E92 before they got removed

 

[JamesBryan]

The dampers are rated the same as the springs so you can go for a 10k damper with an 8k spring for example. Dampers good for 2kg either way for spring rates though

I only know this as I spoke to BC when wanting to spec up the ones on the E92 before they got removed

Ahh right.

Seems weird how you'd want it valved for a higher/lower rate than the spring you're trying to dampen.

Like you say, they're good for a couple kg either side anyway as standard.

 

[-Jamie-]

Probably doesn't make a huge difference tbf seeing as they are pretty janky anyway [emoji23]

 

[banhama]

You can spec the dampers as well as springs in 2kg increments

Interesting, I don't recall having and choice on the damping when I ordered my BC DS, also i would have thought damping would be rated in some sort of 'speed of reaction' type of measurement rather than weight. But I'm far from a suspension expert, just really interested in the topic.

Could be because the DS has 'digressive damping', not sure what the BC BR has but I guess it's Linear.

I think digressive damping force changes with the speed of compression or rebound, where linear damping the damping force is fairly constant through high or low speed compression or rebound.
Where high speed compression is hitting a sudden bump, like a kerb, and low speed compression is what the front springs would experience under braking....more progressive. (Speed is not referring to vehicle speed, rather the speed of the force acting on the suspension)
I think digressive damping favours the low speed actions, and is therefore good for handling on track as you are constantly inducing weight transfer, it may not be so good if you hit a large pot hole or sausage kerb.....but we're not really thinking about driver comfort here!
I think the ultimate is suspension with independently 4-way adjustable high/low compression/rebound. I had this on my Impreza, but I was nowhere near skillful or knowledgeable to make the most of it.

So with 1-way adjustable damping like the BCs I guess you are simply adjusting the overall resistance of the damper to any type of movement.

I have said 'I think' and 'I guess' a lot here so perhaps a suspension guru could give us a simple guide to high and low speed compression and rebound damping, and what's actually happening inside the damper when we fiddle with the little clicky adjuster knob. @Kev@KAM ?

 

[Kev@KAM]

Didn't know that.

Spec them to what exactly?

Doesn't appear to be an option on KAM Racing.

We generally dont offer it as we wouldorder a matching damper and spring.
Basically if you have the wrong spring rate for your application on an already purchased kit then you can get away with replacing the spring with a 2kg harder or softer spring yet still retain the original damper. You would then run damper adjustment significantly harder / softer to compensate. Its not ideal though.

 

[-Jamie-]

That's because the dampers will be spec'd to suit your chosen spring rate lol, I was gonna run a 14k damper to give me the option to run springs from 12-16k

 

[Kev@KAM]

I think the ultimate is suspension with independently 4-way adjustable high/low compression/rebound. I had this on my Impreza, but I was nowhere near skillful or knowledgeable to make the most of it.
@Kev@KAM ?

The ultimate is to be as simple as you can to achieve the desired handling. The 205 track car I'm building I purchased one ways simply because I didnt want to have the complexity trackside to adjust to the conditions. If I had a clever team of mechanics running around after me I might have gone more complicated.

 

[finch wxm]

I was speaking to an old friend from my 200sx days who happens to be a bc racing dealer and they were running a clio with a set and mentioned the valving could be specced but again valving would be done to suit springs picked

 

[Kev@KAM]

Default valving and spring is set for a 4kg front spring. I might have sold two or three sets standard lol.