Bc Racing Coilovers?

[Kanaric]

Can you guys help me make a purchase decision?

Have a R32 GTS-T and am doing SCCA Autocross with it, would like to do track days, about half my use of it and weekend driving. Bought new subframe and differential bushings and am wondering between two different things.

One of the issues i was having is some clunking in the rear which I attribute either to subframe or diff bushings. I want to get suspension, specifically swift springed BC BRs. Will be using near as possible to stock ride height because otherwise I would not be able to get in and out of my garage lol and if I lower it i would probably need more adjustment for my alignment than I can do stock.

The thing is though is other people were suggesting to me in buying basically what comes in this:

http://www.driftworks.com/driftworks-r32-suspension-kit.html

plus lower control arms or replace all suspension bushings. The bushings themselves are expensive and I would have to press them in possibly f**king shit up so I figured just buy new suspension components.

The thing is I get no clunking, uneven tire wear, or anything like that from any part of my suspension aside the area of the rear subframe. So is this really necessary at this stage? Or would I be better served getting coilovers and possibly sway bars? Stock struts are not blown. I know if I go one route or the other I will eventually want both. If you have any suggestions besides what i'm thinking please let me know.

Edited September 15, 2015 by Kanaric

[GTSBoy]

Better off finding out what actually makes the noise.

[Kanaric]

Better off finding out what actually makes the noise.

It is the subframe narrowed it down to that which is good because i bought replacement bushings for that.

[V28VX37]

...

Thanks guys! I'm pretty sure there's enough thread left, I was mostly concerned about the shock travel with an (occasionally) fully loaded sedan.

Theory is though that with a 20% stiffer spring you'd have less travel over the same bump at the same speed than with the softer spring, right?

...

Just in case anyone else is looking at doing this, the BC BR 200mm front springs can definitely be used to replace the 220mm rears.

I've now gone from 6/5 combo to the BC BR default 8/6 with no issues so far.

I did this last week, it's straightforward enough. Seized lock rings gave me some headache and readjusting ride height all around takes a lot of time.

I also realised that the preloads were not consistent and have set that to 4mm all around now.

sounds great, if your car doesnt already have them maybe go for some poly bushings instead of stiffer springs? it would help reduce body roll and retain the good ride quality, plus its a maintenance item that you wont have to replace ever again

Interesting. I've changed virtually of the suspension arms bar LCA's but otherwise most bushings are OEM.

Curious to know how a poly bush would reduce body roll though?

2 things - if you're tracking the car def go the 8/6 spring combo, they're a bit harsh on street sometimes but quite liveable. I woyldn't want softer on the track myself.

Also the chassis bracing you mention - i poo-pooed alot of the bracing you see for skylines - until i actually tried it, and now i'm a huge fan. PM me if you would like any further info on that, its already been covered in threads on here.

So far very good actually, 8/6 is a touch more harsh on sharp bumps/corrugations than 6/5 but not massively, I'm quite impressed actually.

I'm currently running the 8/6 at 5 clicks from full soft, whereas with the 5/6 I used to have them at 10 clicks.

Keen to hear about the chassis bracing Andy if you can PM me some info please?

[GTSBoy]

I'm currently running the 8/6 at 5 clicks from full soft, whereas with the 5/6 I used to have them at 10 clicks.

See this sounds messed up. Stiffer springs need more damping, not less.

[V28VX37]

See this sounds messed up. Stiffer springs need more damping, not less.

Interesting, will need to play around with the settings. I would have thought that full rate of damping adjustment is somewhat acceptable for the default springs (being 8/6) supplied with the coilover? Is there a guide somewhere on matching damping to spring rates?

[hardsteppa]

See this sounds messed up. Stiffer springs need more damping, not less.

The job of the dampers to control the bounce of the spring, and softer bouncier springs having more travel generally speaking (the primary concern being the damper being reasonably matched to the spring rate of course, neither will be giving optimum performance if completely mistmatched). The term 'reasonably' being applicable for a street/soft circuit car, we're not requiring Formulae Uno precision here. Softer springs can be offset to some degree by using a firmer damper to slow down the spring compression giving the 'feel' of a firmer spring. Conversely, a stiffer spring can be made to compress rapidly more easily when a softer damper is used giving the feel of softer suspension. This being easily evidenced by the wide range on adjustment on BC's, mine are only set a few clicks in and if the firmness of the damper is adjusted to halfway the increase is very noticeable; turn it all the way firm and it's like a bloody rock. Possibly granite or quartz, definitely not limestone.

Anyway not discounting your input but could you expand on that gtsboy?

[niZmO_Man]

To stop the spring "bouncing". I'll let the engineer explain.

[GTSBoy]

Yuh, a spring, a mass and a damper walk into a bar. No that's not how it starts. Um, a spring, a mass and a damper combine to form a resonant system. If you just hang a mass from a sporting and pull the mass down from its resting position and let go, it will bounce up and down and yup and down until all the energy you put in by displacing the mass downward (stretching the spring) has been dissipated by friction in the spring. Add a small damper to the system and it will absorb some of the energy on each stroke, this reducing the number of up down cycles and generally making the cycles smaller. This is the underdamped condition. Not enough damping to make the response of the system look much different to the unnamed system. Put just the right sized damper in (ie, a tuned damper rate, you can actually calculate it with the right formulae) and the response of the stem to the initial displacement is to shoot back to the starting position and not actually go past it very far before settling back to the initial position. Of you add in too much damping then the response is to return to the initial position more slowly and never actually overshoot the initial position at all. This is called overdamped. Overdamped systems are actually kinda common on cars, because a tuned system still feels a little too bouncy on cars.

Add more mass to the system with the same sized sporting and you need to add damper in order to meditation the same "tune". Add more showing worth the same mass and you also need to add more damper in order to maintain the same tune.

As has been said earlier(by yourself) people do use unbalanced setups to bandaid not having three right springs, but that doesn't make it the best choice of course.

Edited September 30, 2015 by GTSBoy

[V28VX37]

Just a quick update on my BC BR's; I have just replaced my right rear shock just now as it started leaking, and previously replaced my left rear last year as it got super squeaky. Some more info here.

The left side lasted just under 20,000kms and the right let go just now at about 30,000km, both running 220mm 5kg springs on the sedan for all that time.

I'm not sure if it's the sedan or these coilovers specifically but the rears seem to wear out quicker than the fronts. The fronts seem to be going ok for now but I'll be keeping an eye on them.

[V28VX37]

Thread resurrect.

What damper settings are people running with their BC BR's with the default 8kg front, 6kg rear springs? Specifically on the track.

Last time at Sandown I tried the following:

• Session 1: Full soft, it was very floaty
• Session 2: Full hard, very jittery on the crappy surfaces especially just before turn 2. Also the rear felt 'out of sync' with the front, not sure if that's because of the front heavy car?
• Session 3: Front full hard -8, rear full hard -12. This was better - more cohesive - but didn't get a full sense as I had to cut the session short.

Those last settings were in line with the comments above that harder spring needs more damping, makes sense.

Next time I'll probably try front full hard, rear full hard -8 or something. The BR's have 30 levels of damping adjustment.

[GTSBoy]

Bugger me.  I just read my last post in this thread.  What sort of auto-correct drugs was I on to make so many typing mistakes?

 

Back on topic, I think the last line of your post is close for a smooth track.  Nearly full at the front, a bit softer at the rear.  Have a fling and then try small changes, seeing as you've already done the gross changes and found what you REALLY didn't like.

[G3TFKD]

My current coilovers have finally died in the 32 and I want to get some BCs.

Any recommendations on where to get these? From what I can tell, it is now just JustJap in Sydney selling them? Shame that it is now up to $1399, why couldn't my coilovers die earlier....?

 

[niZmO_Man]

Get MCA.

[Hadouken]

^^^^^^Do yourself a favour and get some mca's.

[GTSBoy]

1 hour ago, niZmO_Man said:

Get MCA.

 

56 minutes ago, Hadouken said:

^^^^^^Do yourself a favour and get some mca's.

 

Would seem to be the sensible consensus for coilovers.

[V28VX37]

 
Would seem to be the sensible consensus for coilovers.

Seeing this a lot lately, MCA > BC.

Could someone who has run both please summarise why MCA's are better?

[GH05T]

do people generally go MCA Blues or is the price for the X series worth the $500

[owen1r]

1 hour ago, GH05T said:

do people generally go MCA Blues or is the price for the X series worth the $500

I think people should be tossing up between X series and Reds! 

X Series are the ones to go. 

[Dose Pipe Sutututu]

been on BCs (not my car) - felt ok...

I own MCA X-R with 10/7 spring rates and feels more planted and less bumpy than a set of BCs with 8/6

Also 32 adjustment on the BC vs 12... ain't no body got time for 32 adjustment points.. heck 12 is 4 too much.