I have spend many hours searching on this topic, but I cannot figure it out and I need some help. I've been lurking here for a while and reading others posts has served me well until now.

I have an NA Chumpcar. I am looking to install a coilover setup (80 points). I believe Bilstein HDs are now point free. I believe KYB OEM replacement foam bumpstops are point free and I can cut them down. I am told I must retain the OEM NA top hats.

1. What should I do for an upper spring centering unit? Will the all star coilover tops be sufficent to center the spring? http://www.summitracing.com/int/part...4174/overview/ It looks like the AWR units are discontinued.

2. Given that the NA top hat allows for less travel and a spring centering unit looks like it might reduce travel further, do you think 6" 550lbs front, 7" 350lbs rear with 5" allstar sleeves will work?

Thanks.

 

I'm pretty sure that it is common to not run any centering units on the coil over sleeves.

 

I am confused as to why you are wasting 80 points on coil overs. I highly doubt they provide enough of a benefit over cutting stock springs to warrant the cost.

 

he;s talking about about 600lb springs on stock stocks. he might as well install rebar.

 

throw in a set of spring rubbers and call the suspension done. best part is you can pull them if it starts to rain.

 

Yeah, local team has run a Miata with just bump stops, no springs. Worked well. Basically high rate springs. Best part is you don't really need a quality shock. Best setup? No. But they got 4th or 5th IIRC.

And Brain, he did say he's running Bilsteins, not stock shocks.

From personal experience, you'll want a 7" front, 6" rear, or 6" all around. My car is pretty light, but not as light as I could make it, and I can BARELY get low enough with a 7" spring in the back, and I still want comfy low, not race low.

 

Thanks for all of the replies.

If you guys think this is a bad idea I'm open to suggestion. The spacer idea has essentially the same points value as springs/coilovers (or best case 1/2).

If stock spring rates can be cut/increased say 50% over factory, I figured it would be potentially riding heavily on the bumpstops. I figured the benefits of coilovers compared to cut stock springs would be: higher spring rate, ride height could probably be lower/better, corner weighing. Given that other options for a similar number of points would be header or sway bars, I figured coilovers with higher spring rates would be better. Agree/disagree?

Do others agree that an upper spring centering unit is not required with NA top hats?

 

Chump racing in general is a bad idea. but we do it anyway.

 

Cut the springs F/R and put on a front sway bar. Put in a good radiator and lighten the hell out of it. This will be a good reliable setup that will be competitive along with being cheap/easy to build.

 

Brain as shitty as the NA R-Package billies are they're actually kind of okly valved for spec miata spring rates. Not great but not hella rice bounce.

 

Are the bilsteins point free? Chump does not allow update/backdate for free, and the MPV is based on a standard model, not an enhanced performance model (like an R-package miata).

OEM-replacements are point free. Non-OEM components are 10 points per component. Cutting an OEM-like bumpstop is point free, but replacing it with a higher grade bumpstop is a 10 point penalty.

FYI, my new Chump project, picked it up last weekend. 92 Infiniti G20 with the SR20DE. It's very similar to a Sentra SE-R, but much cheaper to buy.

 

Unmolested Bilsteins B6/HDs appear to be point free for 2015. I plan to buy a set shortly. I do not have a R-package.

 

You could still have them revalved by someone like bilstien who doesnt add a shrader valve and no one would ever know that they're molested you know. R-package billies from mazda are less hatefully valved if you dont want to spend that much though.

 

Where do you find this info?

 

The rules (non-adjustable, non rebuilt shocks are allowed up to 2x cost of OEM equivalent shock, pricing based on a national auto parts retailer) and the chumpcar forum.

 

Oh I see, 2x for shocks is new for 2015. Rad. Carry on.

 

Does the same rule apply for springs? Coilovers are nice, but a real suspension for "free" would be a pretty big improvement. I'd consider doing a few test days with coilovers, pick a ride height and save the points.

 

No, dampers are now 2x. Springs are the same as the ever were: OEM or cut OEM for free, or non OE springs for 20pts per corner

 

Cut springs are not point add, but any other springs are a point add. Coilovers are the same point value.

Can anyone else confirm if I need upper spring centering units with the NA top hats?

Anyone else have an opinion on the length of springs (say 550/350) with say 5" all star sleeves?

 

Welcome to the Asylum...

I hope you or someone on your team knows those transverse SR20s well...my impression is they can have durability problems in enduro racing. My buddy who had an B13 SE-R PTE car had plenty of issues and he was only sprint racing.