BC Racing coilovers/spring rates for 172

[krappy]

Howdy all - apologies in advance for the long winded post! I am looking for some advice regarding the suspension on my 172.

Currently I am running Koni yellows with Eibach Sportlines, but will be getting my hands on a rollcentre kit shortly. Now I understand that if I were to run the Konis/Eibachs with the rollcentre kit I would need to get them shortened/limited, which I could do relatively cheaply - but seeing as these days the Clio is not seeing so much road use I am seriously thinking about coilovers. This would give me the option for corner weighting and I could then sell-on the Konis/Eibachs to help offset the cost :smile:

The BC Racing coilovers seem to get quite good reviews on here, I am looking at the RN-O-06 kit:

http://www.kamracing.co.uk/car-tuni...lover-type-rn-2-0-16v-rs-172-172-cup-182.html

Anyone have any opinions/comments on the quality/durability after running these for a while?

Also what kind of spring rates do people run/recommend with this setup?

The Eibach Sportlines I am currently on have progressive spring rates of 160-239lb/354-752lb F/R which equates to be about 2.85-4.25kg/6.3-13.4kg (or 28-42N/62-131N approx.). Certainly this setup feels as though it is a bit soft on the front for the track, seeing as the front of the car gets quite a bit of compression under braking/hard cornering (although I am sure this is also partly due to the rollcentres being out). The standard spring rate for the BC's is 4kg/8kg F/R but I have read that this is also a bit soft for track work.

Seeing as I can specify spring rates for the BC's at no extra cost, should I look at going a bit stiffer on the front? And if so how much?

I also believe the rollcentre kit will also affect how soft/hard you can go?

While the car doesn't get driven on the road as much, I still need to get it to and from the track so don't want it *too* stiff but would like something that is a bit more track orientated than currently.

Any advice greatly appreciated :smile:

@MicKPM
@NorthloopCup

 

[bozothenutter]

I have alwayst thought the BC rates were a bit strange.....front really soft and rear relatively hard when billies are 75 front and thpught of as too soft.
You can keep what you have even with the RC kit, as it moves the wishbone down...nut the suspension up.
The RC kit will allow you to go softer up front without getting too much roll as it restores the eoginal goemetry

 

[DCELEC 182]

I run the BC's on my track car, 8kg front 8kg rear (you can only have an 8kg rear spring though, and it equates to half that as it sits in the original 'inboard' position).
Great suspension kit for the money imo, really well designed/made. If they offered a proper coilover rear they would be perfect (I wish they would)!

 

[krappy]

I have alwayst thought the BC rates were a bit strange.....front really soft and rear relatively hard when billies are 75 front and thpught of as too soft.
You can keep what you have even with the RC kit, as it moves the wishbone down...nut the suspension up.
The RC kit will allow you to go softer up front without getting too much roll as it restores the eoginal goemetry

Surprised that the Bilsteins are 75(N?) on the front as well! I searched for the spring rates for the B14s but couldn't find them, as I did for the KWs - purely to compare as a couple of friends in Clios that I have done trackdays with run those and they comment that they are too soft for track. If that spri g rate for the Billies is correct, maybe the reported softness is also to do with the fixed rate damping?

I know I can keep what I have currently but the Konis will need to be altered to limit the travel, otherwise I'll the rollcentre kit will bottom out. I was just thinking that if I sell them on I could also put the cost of limiting them towards coilovers and have a set for not that much more. Plus it gives me the option for corner weighting if I want to do it

Yeah I had read that rollcentre kit will allow me to use softer rate springs as the front suspension will be back to optimal geometry and therefore won't be working as hard as it is currently

 

[krappy]

I run the BC's on my track car, 8kg front 8kg rear (you can only have an 8kg rear spring though, and it equates to half that as it sits in the original 'inboard' position).
Great suspension kit for the money imo, really well designed/made. If they offered a proper coilover rear they would be perfect (I wish they would)!

So you can't specify anything else other than an 8kg spring on the rear?

I believe you were running the 5kg spring on the front before yeah? Obviously the 8kg springs is quite a bit firmer, how does that compare to the 5kg on track? Do you drive the car on the road at all - if so how did you find the 5 and 8kg springs on the road?

TIA

 

[DCELEC 182]

So you can't specify anything else other than an 8kg spring on the rear?

I believe you were running the 5kg spring on the front before yeah? Obviously the 8kg springs is quite a bit firmer, how does that compare to the 5kg on track? Do you drive the car on the road at all - if so how did you find the 5 and 8kg springs on the road?

TIA

I phoned BC direct earlier in the year when I was looking to change spring rates, there's plenty of options available for the front coilovers as you'd expect but as the rear springs are in the oe position they're progressive not like a coilover spring and he told me it was too expensive to make different spring rates for the rear as they'll be specific to a clio where the fronts fit all sorts of Coilovers.
I've done two days so far this year on the 8kg springs, with a noticeable improvement to be honest once I'd got used to how the car handled on the new setup, I've added a gripper diff now as well. Is very much track dependant though as to what spring rates will suit but the combo I've got seems to work well. If you go up too high spring rate wise on the front without upping the rears the car will become unbalanced and probably start understeering of anything!
Car isn't used on the road apart from driving to and from tracks, at the moment.
The old 5kg springs with the dampers on a soft setting drove really well on the road.
The 8kg springs have made the ride a LOT harsher though, I wouldn't want them on a road car.
Hope this helps

 

[Greeny.]

I have the 5kg's and I'm finding that they give me abit of bump steer but my car is far from setup atm! Ideally want to change them at somepoint. I found the best balance on track was 17 clicks from soft on the 5kgs.

Love the shocks though

Dan

 

[Steven103]

Springs don't give you bump steer, rappers do... wait what

Overly stiff springs or dampers give you twitchyness. Poor suspension geometry gives you bumpsteer. Messing with the suspension and not checking alignment can give very err "responsive" amounts of toe.

If it is genuine geometry-induced bumpsteer, then the roll centre kit or PMS bumpsteer kit will help.

Oh and knackered bushes or soft bushes + mega hard springs can give you strange direction changes under load.

 

[Greeny.]

Springs don't give you bump steer, rappers do... wait what

Overly stiff springs or dampers give you twitchyness. Poor suspension geometry gives you bumpsteer. Messing with the suspension and not checking alignment can give very err "responsive" amounts of toe.

If it is genuine geometry-induced bumpsteer, then the roll centre kit or PMS bumpsteer kit will help.

Oh and knackered bushes or soft bushes + mega hard springs can give you strange direction changes under load.

Interesting... tbh I was abit annoyed when I was told on here it was the springs considering I bought the 'track day' BC spring variant, here is my original thread, although after playing with tyre temps/dampening it has got better: http://www.cliosport.net/threads/advice-on-setup.774226/

People were basicily saying my front springs were stiffer than the road set 5kg vs 4kg and that I had removed to much weight from the car causing the skipping, although @DCELEC 182 has changed his fronts to 8kg so even stiffer?! This confuses my little brain somewhat

 

[DCELEC 182]

Those springs won't be causing the bump steer mate. 5kg isn't even a stiff spring as they go track car wise!
What issues/symptoms have you had?
Geometry as said is the likely cause.

 

[NorthloopCup]

@krappy I'll reply later on mate. I've been a bit too busy to reply the past few days.

 

[krappy]

I phoned BC direct earlier in the year when I was looking to change spring rates, there's plenty of options available for the front coilovers as you'd expect but as the rear springs are in the oe position they're progressive not like a coilover spring and he told me it was too expensive to make different spring rates for the rear as they'll be specific to a clio where the fronts fit all sorts of Coilovers.
I've done two days so far this year on the 8kg springs, with a noticeable improvement to be honest once I'd got used to how the car handled on the new setup, I've added a gripper diff now as well. Is very much track dependant though as to what spring rates will suit but the combo I've got seems to work well. If you go up too high spring rate wise on the front without upping the rears the car will become unbalanced and probably start understeering of anything!
Car isn't used on the road apart from driving to and from tracks, at the moment.
The old 5kg springs with the dampers on a soft setting drove really well on the road.
The 8kg springs have made the ride a LOT harsher though, I wouldn't want them on a road car.
Hope this helps

Great info mate - many thanks! When you explain it like that you can see why they do only offer the one spring for the rear - didn't realise they were progressive though, and assuming the info I found on spring rates is correct the Eibach rears are a fair bit stiffer. The 5kg springs would be about 18% stiffer than the Eibach fronts though (but not progressive so firmer initially than the Eibachs as well?) but sounds like they would still ride quite well on road. 6kg would be about 40% more but might be tending towards being too stiff for road, wonder if something halfway would be ok - do they do 5.5kgs springs?

I can imagine that the 8kg springs would have made quite a difference to the handling, as would the gripper! I had a quick drive of a mate's clio that had the rollcentre kit and a quaife and my god, the difference to how my car handled was like night and day! It was eye-opening! Not sure how much of the difference was rollcentre kit or LSD but I am hoping a fair bit of it was the rollcentre kit lol, by all accounts it should improve things quite a bit though :smile:

I have the 5kg's and I'm finding that they give me abit of bump steer but my car is far from setup atm! Ideally want to change them at somepoint. I found the best balance on track was 17 clicks from soft on the 5kgs.

Love the shocks though :smile:

Dan

Springs don't give you bump steer, rappers do... wait what

Overly stiff springs or dampers give you twitchyness. Poor suspension geometry gives you bumpsteer. Messing with the suspension and not checking alignment can give very err "responsive" amounts of toe.

If it is genuine geometry-induced bumpsteer, then the roll centre kit or PMS bumpsteer kit will help.

Oh and knackered bushes or soft bushes + mega hard springs can give you strange direction changes under load.

Interesting... tbh I was abit annoyed when I was told on here it was the springs considering I bought the 'track day' BC spring variant, here is my original thread, although after playing with tyre temps/dampening it has got better: http://www.cliosport.net/threads/advice-on-setup.774226/

People were basicily saying my front springs were stiffer than the road set 5kg vs 4kg and that I had removed to much weight from the car causing the skipping, although @DCELEC 182 has changed his fronts to 8kg so even stiffer?! This confuses my little brain somewhat :smile:

Those springs won't be causing the bump steer mate. 5kg isn't even a stiff spring as they go track car wise!
What issues/symptoms have you had?
Geometry as said is the likely cause.

I get that 'bouncing' sometimes in my car too - usually in tighter, slowish corners after a heavy braking zone. I think that the reason is due to the rollcentres being out, but I found it was worse when I ran the Konis at full hard up front - softening off the Konis a half turn improved it somewhat. So possibly a combination of both - dodgy rollcentres and damper set too hard for relatively soft springs? FWIW my car isn't stripped, I take out the spare wheel/toolkit/floor mats/parcel shelf/boot carpet and that's about it, so it certainly isn't anything to do with being too light lol. And I suffer from a bit of bump steer as well.

@krappy I'll reply later on mate. I've been a bit too busy to reply the past few days.

No problem mate - whenever you get a chance! Just tagged you as I thought with the rollcentre kit in the equation you would be the person to seek some wisdom from :smile:

Also re: Bilstein B14s, if they are really rated at 75N up front yet are thought of as too soft for track I was wondering if perhaps they are a progressive spring? So initially are quite a bit softer?

 

[bozothenutter]

Why were you runnig full hard on the fronts mate?

 

[krappy]

Why were you runnig full hard on the fronts mate?

Because racecar :tonguewink:

Haha no not really - I normally run the Konis at 1.5 turns on the road anyway. I was trying them firmer on the front to see if I could stop the front diving so much but found that at full hard I was getting the bouncing so wound it back a bit which helped...

 

[Steven103]

TBH it sounds like you've already found the least-worst damper setting for the unique combo of you & your car/roads/usage/preferences and bouncing problem.

Is the bouncing in a straight line or just corners? Have a play with rear damping if it's in a straight line.


The ratio of things that play a part to things you can sensibly change isn't exactly in your favour.

There are 6 springs on each corner of the car. 2x progressive rate air springs (tyre & gas chamber in damper), 3x progressive rate springs (coil spring, topmount & spring aid) and 1x linear rate spring (ARB).

Nevermind all the other things you could namedrop from vehicle speed to obscure suspension geometry effects. And you're controlling all that with one dial (which IIRC only does rebound damping on the koni's).

 

[krappy]

Thought I should update this as things have moved along somewhat.

After much thought re: the BC's I ended up getting an excellent offer on a set of barely used B14's (swap for the Konis/Eibachs and a bit of $$$), actually off the Clio that I was getting the rollcentre kit from. After fitting the B14's and the rollcentre kit and getting an alignment and cornerweighting done, the car now feels amazing! Ride is firm but not harsh (feels very well damped), corners nice and flat, less diving under braking and has heaps of grip, steering feels a bit lighter too - basically feels like a massive step up over before. Really looking forward to seeing how it feels out on track - I know that a lot of people feel that the B14's are a bit soft for track work but initial impressions are that it should be a good improvement over the previous setup. The B14's definitely don't feel soft put it that way, but will see how they feel when pushing on track.

I also managed to pickup a cheap set of 15" semis on TD 1.2 rims, so after running the new setup on the AD08Rs to try and get a direct comparison on similar rubber I'll pop those on and see what that does. I haven't used semis before so will be interestimg to see what that's like! Hopefully a lot quicker haha!

 

[krappy]

Forgot to add, thanks again to you all for the advice re: BCs/spring rates- I think if I do intend to go down the BC route in future I will actually have a better idea of what I will want/need after running these B14's. If they feel too soft on track then I will know I need to go harder, and what that may potentially feel like on the road - the only trick will be trying to work out what the spring rate for the B14's actually is!