What BC Coilover spring rate to go for in a Stripped out 172?

[Trackslag172]

Hi All,
I am looking for some advice, and kind of fast (need to order them Friday morning). For those that haven't seen my other posts or project thread (link below), I have just started work on a 172 track car but know very little about how cars actually work, I only started on Friday so I am learning as I go.
http://www.cliosport.net/threads/2003-172-track-car-build.780909/#post-10864538

I am about to order some BC coilovers from a friend and have been given the option of different spring rates and height of the struts. I have no idea what to tell him and he doesn't know enough about Clio setups to tell me. So I am asking you, the lovely people of Clio Sport :smile:.
Ideally I am looking for someone who has lots of track experience and experience with BC coil overs, but I will take what I can get :tongueout: the car is completely stripped out so very light at the rear which I guess will make a difference.

The standard spring rates for BC coilovers are 4kg front and 8kg rear - but I can choose what I like. Can anyone give me any advice?
Also should I opt for longer struts to give me more travel? if so how long/high?

I am also hoping to get a full set of figures for a suspension set up, e.g. caster, camber, toe etc but I will do another thread for that in a week or 2 as it will all go over my head right now.

Thanks for any advice, this is all beyond me at the moment, I have a lot of reading up to do
Cheers,
Tim

 

[JamesBryan]

8kg front and rear if it's for track.

 

[StuOwen86]

I'm thinking about changing the springs on my BC coil overs (also a set of spanners for adjusting the height too but that's another thread), not sure what they are as i bought the car with them on any idea how you check what they are? Mine has a bit too much roll according to the instructor I went out with at Oulton and since putting on my 888 I'm carrying a little more speed into Shell Oil hairpin and get (what sounds like) my passenger side suspension bottoming out, about half way round there is a little bump in the road and that's the only place it happens. Typical too, just sat here now typing and I didn't even think to go out on my own and see if it happens with no weight in the passenger side (off to kick myself) as I share the car with my dad and were always 2 up in the car so its probably an extra 90kg of weight (I'm not a little lad lol)

 

[Trackslag172]

I have been doing some reading, mainly on this forum, and realised that this is a much more debated topic than I thought.

8kg front and rear if it's for track.

Should I not have a slightly stiffer front 8kg/7.1kg (450/400lb) as it has all the weight?

I'm thinking about changing the springs on my BC coil overs (also a set of spanners for adjusting the height too but that's another thread), not sure what they are as i bought the car with them on any idea how you check what they are? Mine has a bit too much roll according to the instructor I went out with at Oulton and since putting on my 888 I'm carrying a little more speed into Shell Oil hairpin and get (what sounds like) my passenger side suspension bottoming out, about half way round there is a little bump in the road and that's the only place it happens. Typical too, just sat here now typing and I didn't even think to go out on my own and see if it happens with no weight in the passenger side (off to kick myself) as I share the car with my dad and were always 2 up in the car so its probably an extra 90kg of weight (I'm not a little lad lol)

What spring rates and strut height do you currently have?

 

[bozothenutter]

@NorthloopCup
Listen to this man....

 

[Trackslag172]

Ive just been reading his (and your) comments on an old thread
http://www.cliosport.net/threads/ag...-coilover-and-spring-rate-debate-help.747358/

He was running 450/475 on sportline2's. is that comparable to the BC's?

 

[StuOwen86]

I couldn't tell you what I have now as I don't know mate. Was wondering how too find out myself.

 

[Mini182]

Ive just been reading his (and your) comments on an old thread
http://www.cliosport.net/threads/ag...-coilover-and-spring-rate-debate-help.747358/

He was running 450/475 on sportline2's. is that comparable to the BC's?

The thing with the BC's is that they don't run a rear coilover setup, they use the original spring locations.

So the rear springs would need to be harder than the AST's to get the same spring rate, as the leverage force will be greater on the original spring platforms.

 

[Trackslag172]

The thing with the BC's is that they don't run a rear coilover setup, they use the original spring locations.

So the rear springs would need to be harder than the AST's to get the same spring rate, as the leverage force will be greater on the original spring platforms.

I have been texting @-Dan- this evening and he said exactly the same thing. He advised going for stiffer springs on the rear and to work it out on the BC rears add 30% to the equivalent full rear coilover. So if I wanted a 6kg rear spring, I would go for a 8kg as its a platform set up.

I am looking to order Standard length struts with Front/Rear 8kg/11kg (448/616lb) (78/108nm). As an approximation to the 450/475 AST set up (that I can't afford 😞)
Can anyone see a problem with that, as previously mentioned, I know only the very basics about suspension so all input welcome

 

[StuOwen86]

Would also be interested in knowing what springs would be best for my 172 (track car) if i need to order some, would the above same as Trackslag172 going for a 8kg front and 11kg rear be the better option?, I'm hopefully going to try and find out what rate the springs are on mine on Monday when the car is up on ramps.