Which Koni's for my NA8?

geoffblick · Postby **geoffblick** » Sun Apr 21, 2013 3:08 pm

Guy behind me at Phillip Island yesterday told me that the front of my stock NA8 was almost touching the ground & in his words "you could stick your head between the wheel arch & your rear tyres". He suggested that my struts were either too old or too soft. On not very good Pirelli P6's my best time was a slow (and embarrassing) 2minutes & 20 seconds. My question is. What is the cheapest way to go to replace the struts & get reasonable performance? Is there an alternative to Koni & what should I pay? The car is not a daily driver so I don't mind losing some comfort in the ride. Last question is. Do I need to replace my split boots or can I leave them off?

lee · Postby **lee** » Sun Apr 21, 2013 4:27 pm

I got my Konis from Shox.com for $650 landed. They also sell Eibach springs which are possibly worth looking in to. A lot of people here recommend getting FatCat Motorsports bumpstops as well, I got mine for around $140 landed.

manga_blue · Postby **manga_blue** » Sun Apr 21, 2013 6:57 pm

If you're running in the MX5 Vic club comp then any modification, including shocks or springs, will take you straight out of standard NA (SNA) class into Clubman. Is that what you want to do? Stock NA8s are still fairly quick. The club's SNA lap record is 2:04 at the Island (thanks to Noel yesterday, amazing!) and I can assure you that's with a fair bit of body roll. Tyres make a far bigger difference than shocks. I went from 2:24 to 2:08 between sessions just by swapping from Goodyear Eagle F1 to Yokie C-Drive tyres. Nowadays Dunlop DZ101 Star Specs are much quicker than the C-Drives.

Also suggest you talk to Rob Downes or Noel Heritage about where to pick up time before you modify.

lee · Postby **lee** » Sun Apr 21, 2013 7:37 pm

If you're keen on staying in SNA class, I have some ~130,000 km old stock shocks & springs you can have for whatever you think is reasonable

geoffblick · Postby **geoffblick** » Mon Apr 22, 2013 4:28 am

Thank you all for the feedback. I want to stay in stock class so what are my options in replacing the shocks? Do they have to be stock Mazda parts or can I go for another brand?

sailaholic · Postby **sailaholic** » Mon Apr 22, 2013 7:41 am

manga_blue wrote:If you're running in the MX5 Vic club comp then any modification, including shocks or springs, will take you straight out of standard NA (SNA) class into Clubman. Is that what you want to do.

This is retarded. I can accept spring changes is a mod happily, but shocks are a wear item! What do they expect people to do? I doubt you could even get factory replacement units now.

Could the OP use clubman bilstien units? At least these are rebuildable.

Out of interest does the stock class require oem brake pads to be fitted as well?

manga_blue · Postby **manga_blue** » Mon Apr 22, 2013 10:46 am

It's not retarded. It's all about keeping it competitive and low cost. OEM style replacements are OK for brakes, clutches, suspension, whatever.

Monroe, Pedders and KYB all make OEM non-adjustable replacement shocks which should still keep you in SNA, but I'd check with Daniel or Russell about classing before splashing out.

Given what you've described I'd be checking out the suspension for problems or damage to springs, rollbars, control arms and their mountings.

If you don't do the work yourself it might be a good idea to speak to Dean at Motorsport Essentials. He has done preparation work on Rob/Noel's car (among many others) and knows a thing or two about getting an SNA to go fast. He's also very good at sourcing parts cheaply and his work is up to the standard you need for track work.

Otherwise you could call Pedders. They usually have good testing equipment and can machine test your shocks and check the rest of the suspension before asking you to spend on parts. I have a personal policy of not replacing parts that don't need replacing. If you've read Guran's "Little Reddy" thread in Garage Chat you'll notice that he's still setting NSW SNA lap records on original Mazda shocks with 190,000kms on them.

If you're doing the work yourself then I'd be tempted by lee's offer. Get those, take them to Pedders for testing and then whack them in.

sailaholic · Postby **sailaholic** » Mon Apr 22, 2013 2:10 pm

I read it as any modification being, "if it didn't come out of the factory with it you can't use it". As long as replacement is allowed with SIMILAR units then I can completely understand the rules.

Steampunk · Postby **Steampunk** » Mon Apr 22, 2013 5:37 pm

Koni brought out those orange STR.T dampers a few years ago with mixed reviews, so you can try those if you really want to use Koni. As stated, why not get Clubman Bilsteins.
I quite like KYB Excel-G for OEM replacement BUT if you think your springs are getting on and are saggy, forget it. Although they have good rebound, they rely on good condition springs to be optimised.

manga_blue · Postby **manga_blue** » Mon Apr 22, 2013 8:10 pm

Clubman Bilsteins are an upgrade under Vic rules, so are virtually any Konis. Valving needs to be as near as possible to stock. This is a class for bog standard NAs and it's probably the most desperately contested competition in the country, if not the planet.

Matty · Postby **Matty** » Tue Apr 23, 2013 11:57 am

Ditto to everything manga said. With the double wishbones and camber patterns on the MX, body roll doesn't slow you down much, and shocks alone won't limit body roll (springs will). The car wallows but you can mostly drive around that, the rubber stays pretty flat on the road.

In an NA, the shock boots are integral with the bump stops (or they are when the car is new). Not necessary to change them but it's nice to have fresh rubber. If it was a road car I'd say change the bushings with new ones, but I've heard that Spec Miata racers prefer older ones because they go hard as they age.... Max out the camber and you should be about as good as you can get in that class.

Amazing lap times happening now; tyre tech has come a long way in the last 10 years! (and some faster tyres are now allowed in standard it seems)

hks_kansei · Postby **hks_kansei** » Tue Apr 23, 2013 12:40 pm

manga_blue wrote:Clubman Bilsteins are an upgrade under Vic rules, so are virtually any Konis. Valving needs to be as near as possible to stock.

How is "near as possible to stock" determined?

Just going off the manufacturer saying "OEM replacement", "OEM Equivalent"

Or is there a list of specifically allowed shocks?

geoffblick · Postby **geoffblick** » Tue Apr 23, 2013 12:43 pm

Looks like we will go for Pedders. I am going to get my mechanic to do the job & he is researching which Pedders will be the best. Thank you for your advice.

geoffblick · Postby **geoffblick** » Tue Apr 23, 2013 4:31 pm

Just got the quote. For Pedders plus boots & stops & allowing I hour labour per corner. Under $1300. I told him to book it in.

Steampunk · Postby **Steampunk** » Tue Apr 23, 2013 4:48 pm

geoffblick wrote:... allowing I hour labour per corner. Under $1300...

Getting ripped on hourly rate and RRP, but hey, it's SOP Pedders.
A professional shop should take no longer than 30mins per corner, heck, my mate and I did it in 2.5 hours and that was going slow and steady.

Sourcing your own set-up then paying a shop a couple hundred $$ would save you several hundred $$.