Polybush Vs Standard Rubber - Coilovers Vs Spring/Shock

[racer]

So 'racer' has said 250/300 and polybushes - well he would he's a maniac!

That will make the car quite responsive (from experience) but a bit thumpy!

250 isn't really hard though Rob. People forget that on a 2.5/2.25 spring the rate equivalent is less than a full size spring.
I'm running 400lb on my car but with good dampers the car is still not overly crashy.
It’s the solid mounts and complete lack of carpet and sound proofing that make it harsh.

It’s the shell that’s the limiting factor with springs. Too hard and the body will just flex like crazy in hard cornering.
Fit a cage and cross brasses and squeaks and rattles will be reduced.

A good restoration with nice fitting panels inside and outside the car should help also imo.

 

[racer]

I certainly don't want it to be a super harsh ride. A slightly harder than standard ride with good dampening will do me fine!

Im considering the BC Coilovers to get both a matched damper setup I can spec the spring rate on and camber adjustment...

I'm not sure if the BC legs are adjustable? If not you may be stuck with what the manufacturer sees fit for a spring rate for their dampers.

 

[jonbills]

250 isn't really hard though Rob. People forget that on a 2.5/2.25 spring the rate equivalent is less than a full size spring.

I know that seems to be the case in practice, but it makes no sense to be. the spring rate is the spring rate. A 250 lb/in spring requires 250 lb force to compress it 1 inch. The diameter of the spring shouldn't come in to it.

Can anyone explain?

 

[racer]

I'm no expert either John, we need Mr Skiddell for a full explanation.

 

[s2k_adz]

So I think Ive decided on going for the BC coilovers on my car as I can spec a spring rate, adjust the camber, albeit by dropping the shock down then bolting it back up, and adjust the dampening.

So.... next question, what would you guys recommend as a spring rate for a car thats going to be used on weekends for blasts around the countryside and maybe the very odd classic track day? I see I've already caused a debate regarding this!

I think they will be run with polybushes if that makes a difference!

 

[s2k_adz]

170/200 Front/Rear has been mentioned and 250/300!

BC Coilovers seem rated standard at 4/5kg front/rear.

One other thing, on the BC listing it lists 70-73. Whats the difference between fitment for an early 240/60 and a 260? Will they still fit?

 

[astroboy]

170/200 Front/Rear has been mentioned and 250/300!

BC Coilovers seem rated standard at 4/5kg front/rear.

One other thing, on the BC listing it lists 70-73. Whats the difference between fitment for an early 240/60 and a 260? Will they still fit?

Hello mate, this may come in handy?

http://forums.hybridz.org/topic/117236-bc-racing-coilovers-for-s30-now-offering-extreme-low-kits/

 

[s2k_adz]

Hello mate, this may come in handy?

http://forums.hybridz.org/topic/117236-bc-racing-coilovers-for-s30-now-offering-extreme-low-kits/

Just this minute found that mate thank you! I guess as long as it's a 55mm body it's all good then? Are lengths etc the same?

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[astroboy]

Just this minute found that mate thank you! I guess as long as it's a 55mm body it's all good then? Are lengths etc the same?

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I think so. I haven't read that thread in detail for a while but it's the case of being very Honda.

Find the parts and just 'bolt on'.

My understanding is that no cutting/welding is required. I would spend some money getting the camber plates though...

Where are you getting yours from?

 

[astroboy]

I think so. I haven't read that thread in detail for a while but it's the case of being very Honda.

Find the parts and just 'bolt on'.

My understanding is that no cutting/welding is required. I would spend some money getting the camber plates though...

Where are you getting yours from?

Bear in mind my info is regarding the spec coilovers on that thread, not sure what your getting nor have I matched it up to any info in the thread.

 

[astroboy]

I think so. I haven't read that thread in detail for a while but it's the case of being very Honda.

Find the parts and just 'bolt on'.

My understanding is that no cutting/welding is required. I would spend some money getting the camber plates though...

Where are you getting yours from?

Scratch that, the bolt on versions are not being made.

 

[johnymd]

I think all of this type of kit require you to cut and weld your existing strut. The type that don't are ttt or az.

 

[s2k_adz]

Yea I've yet to find one that doesn't require cutting. It's a bit of a pain as it takes away some originality I guess. It would be good if someone could design a system to make the hub bolt on to the shock! A few cars I've had have a collar with a nut that's tightened.

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[johnymd]

THe BC kit does look like a buy as I cant see anything else in that price range. You would spend more than that on converting your own struts to raised platforms and new adjustable dampers.

Some has modified Z31 struts to take the clamp on type dampers but I can't find to page now.

 

[s2k_adz]

THe BC kit does look like a buy as I cant see anything else in that price range. You would spend more than that on converting your own struts to raised platforms and new adjustable dampers.

Some has modified Z31 struts to take the clamp on type dampers but I can't find to page now.

It seems there's so many people cutting them up it does make sense to sort a bolt on option John! Do you have any idea what spring rates I should go for?

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[SKiddell]

Do you plan on running a moderate to significantly lowered car.
If so sectioning the struts to fit a shorter stroke damper is somewhat mandatory.

 

[johnymd]

I now run 350lb all round but mine is more track orientated. For a road car I'd probably run 250 to 275. My weight distribution is 642kg both front and back with me in the car and half tank of fuel so I run the same spring rate at both ends. I was running a lower rate at the back but this was noticeable too soft. Changing to the same rate all round made a massive difference. Some of the americans run a higher rate at the back and they also often run without antirolbars. I run the MM uprated bars and adjustable camber plates with 2.5neg front and 1.5neg at the back.

Getting back to your car and its main use, I wouldn't get too hung up about all this. Any new dampers will feel great and if you can adjust the rate to suit your preferred comfort level, then all the better. Adjustable platforms will let you lower the car which will also improve the handling as well as the looks. Zeds handle good anyway so you probable only need a few tweaks to make it better without loosing comfort. For the price your paying for the BC kit you cant go wrong. I would go for their shortened kit (which I think is the standard one) and not the extreme lowered version. Then probable go with their recommendations for street rates. Ask them what 4/5kg is in lb's. Give me a ring if you want to chat about it a bit more.

 

[jonbills]

conversion from kg/mm to lb/in is divide by 0.0179.
so 4 is 223 lb/in, 5 is 279 lb/in

 

[astroboy]

Dare I say it.

Air suspension.

** Runs away and hides awaiting fallout **

 

[johnymd]

Air suspension - I had thought about this after watch the "Fast and Loud" GT40 last week that ran on air. Go on, be the first...............oh no, I think its already been done to a 240.