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Old 02-19-2015, 10:32 PM   #1
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Default Chumpcar Coilover Question

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.
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Old 02-19-2015, 10:39 PM   #2
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I'm pretty sure that it is common to not run any centering units on the coil over sleeves.
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Old 02-24-2015, 09:39 AM   #3
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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.
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Old 02-24-2015, 09:41 AM   #4
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he;s talking about about 600lb springs on stock stocks. he might as well install rebar.
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Old 02-24-2015, 09:48 AM   #5
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throw in a set of spring rubbers and call the suspension done. best part is you can pull them if it starts to rain.
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Old 02-24-2015, 10:22 AM   #6
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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.
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Old 02-24-2015, 10:30 AM   #7
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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?
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Old 02-24-2015, 04:00 PM   #8
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Chump racing in general is a bad idea. but we do it anyway.
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Old 02-24-2015, 04:29 PM   #9
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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.
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Old 02-24-2015, 09:35 PM   #10
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Quote:
Originally Posted by Braineack View Post
he;s talking about about 600lb springs on stock stocks. he might as well install rebar.
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.
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Old 02-25-2015, 10:11 AM   #11
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Quote:
Originally Posted by Snrub View Post
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.
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.
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Old 02-25-2015, 10:15 AM   #12
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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.
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Old 02-25-2015, 10:18 AM   #13
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Quote:
Originally Posted by Snrub View Post
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.
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Old 02-25-2015, 10:32 AM   #14
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Quote:
Originally Posted by Snrub View Post
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.
Where do you find this info?
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Old 02-25-2015, 10:38 AM   #15
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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.
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Old 02-25-2015, 10:41 AM   #16
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Oh I see, 2x for shocks is new for 2015. Rad. Carry on.
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Old 02-25-2015, 03:40 PM   #17
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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.
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Old 02-25-2015, 04:27 PM   #18
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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
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Old 02-25-2015, 04:29 PM   #19
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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?
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Old 02-25-2015, 04:31 PM   #20
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Quote:
Originally Posted by Ben View Post
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.
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.
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