Track day car advice please

Slowcoach · Post by **Slowcoach** » Sat Mar 08, 2014 10:38 pm

Hi all

(I've searched but failed to find - maybe looking in the wrong forum)

I'm interested in getting an MX5 and doing some light mods to make it a reliable track car (and possibly Targa).

I'm not wanting to build a berserk speed machine from the beginning, but needing your advice about starting car (year, engine, various specs) so that I don't snooker myself later when trying to add power/reduce weight/improve suspension etc...

So, what's the best starting point? Older = lighter? Newer = stiffer? Older = more bolt on options? Newer = better drivetrain/brakes?

Thanks in advance

marcellarius · Post by **marcellarius** » Sun Mar 09, 2014 1:47 am

I'd be inclined to go for a first or second generation (NA or NB); the styling is different but the chassis is very similar, a lot of stuff is interchangeable.

Get the best specimen you can afford. The 1.6 and 1.8 have similar power-to-weight, both are reliable engines with strong internals, ideal for a forced induction setup.

If you're planning to use it as a track car, you will need to roll protection. If you want to compete in MSNZ events the roll bar needs to be homologated. I suspect for Targa you'd need a full roll cage, which isn't really safe in a street car.

If you're at the taller end of the spectrum, driving position and head clearance can be improved with a race seat.

The cars came with a couple of differential options over the years. The NA6 (1.6, 1989-1993) had an open diff as standard, a viscous LSD was an option.
The NA8 (late 1993) and NB has a larger, stronger differential and came with an open diff or Torsen LSD as an option. The Torsen is a good, versatile diff, robust, and doesn't need regular rebuilds.
There are various clutch LSDs available for both types of diff; and the "1.8" rear can be retrofitted to the NA6 if desired.

Plan on upgrading the suspension to something more sporty... with a good wheel alignment the OE suspension handles well, but it's very soft and is designed to roll onto the bumpstops in corners.

Good luck

Ian · Post by **Ian** » Sun Mar 09, 2014 8:01 am

Welcome.
Been there/done/doing that...lol
I started with a NA8 and have no regrets. If starting again, I would look for a 1.8 NB, ideally an RS with torsen as standard and if it had a hardtop that would be an advantage as you will need one for competition.
Happy to help if you wish to PM me...

Ian

Snapfrozen · Post by **Snapfrozen** » Sun Mar 09, 2014 8:56 am

You've got a few "best options". Here's how I see it.

Avoid an early NA - They have a short nose crank that commonly has faults. This isn't a deal breaker, hell, my track hack has one. However if you ever need to rebuild it might mean a complete swap.

I'd take a 2002 NB Sport for a already done package.

-Huge brakes (Biggest of the lot from factory) with easily available pads, then you just need some good fluid.

-Awesome power from factory - more than enough to have fun

-Slap in some suspension and some semislicks and a rollbar/cage and away you go.

As far as a cage not being safe in a street car, I dispute that. Hitting your head on a padded rollcage is no different than hitting it on the window, the edge of the roof etc. Ultimately if you get hit that hard, you'll have your harnesses on so not likely to move that far, and they don't stretch a HUGE amount and have probably got bigger problems.

If you want a fun weekend car to dabble with and spend less to begin, buy an NA, slap in a Torsen, rebuild an engine, slap on a hairdrier and retrofit some brakes, suspension and you'll likely be away for cheaper than an NB

You also will not need a hardtop for competition, you'll need a rollcage

SLYDIT · Post by **SLYDIT** » Sun Mar 09, 2014 9:48 am

whats your budget?

first you need to ask whether you will use it in the mx5 racing class because that will limit modifications. probably the best "bang for buck" mx5 racer would be an 1800 NA or cheap NB with a turbocharger fitted, good suspension (fatcat motorsport kit maybe).. and some 15x8 6UL wheels and some good pads/tires.
that will be very fast but being a turbo would limit your entry into some classes.

at the other end on the scale is the latest shape NC mx5 which can be had for under $20K. youd only have to fit some nice suspension,rubber and pads to be pretty fast as the chassis is damn good.you can even get turbo's for this model too which puts you into porsche speed territory.(0-100 sub4.5 seconds. 300WHP)

Slowcoach · Post by **Slowcoach** » Sun Mar 09, 2014 10:47 am

Thanks all - great comments.

Budget… how long is a piece of string? Initially I'd want to spend less than 15k all up. More later perhaps

Why no love (apart from SLYDIT) for the larger engine NC? More complex/fatter?

Car is for track day fun initially, later I may want to get into race series so wouldn't want to do anything crazy that would require later removal (V8's! Turbo? Supercharger?)

Roll bar / cage - would probably go straight for the cage. Is there a 'best' homologated version? Different fabricators have different ideas - some good, some marginal. I'm only 5 foot 6 inches or so, and would put a race seat in straight away too, so should be ok (though can a roll cage work with a hard top?)

In my view, ideal sequence would be:
Safety (WOF, cage, belts, brake pads/fluids, bushes)
Reliability (clutch, gearbox, diff, fluids, belts, hoses)
Handling (springs/shocks, roll bars, tyres, brake rotors/calipers/lines)
Speed (weight reduction, engine power)
Aesthetics (go-fast stripes etc)

More or less correct? Are there items on these cars that are prone to failure? Radiators, diffs etc?

SLYDIT - is there a particular model of NC that would be a best base for porsche beater? (like the NB start point suggested by Snapfrozen's 2002 sport?) So many options/versions when you start to look (for a newb).

Thanks again!

Snapfrozen · Post by **Snapfrozen** » Sun Mar 09, 2014 11:09 am

You're bang on with the order to do things in. Just remember you'll make a bigger dent in laptimes with suspension, brakes, tyres and seat time than power.

I'd be inclined to get some semi slicks on it and take it straight out on the track. Then get some suspension in and good brake fluid in, then repeat. Then worry about aftermarket brakes (I've raced seasons on a factory setup, I don't believe in spending $2k on brakes in a light car). Race pads, Motul 660 fluid. Then worry about the seat, cage and harnesses. You might get to this step and hate the body and decide to sell and go for an NA/NB/NC.

I think the most aftermarket parts are available for NA/NB which is why theres so much love.

marcellarius · Post by **marcellarius** » Sun Mar 09, 2014 11:28 am

I quite liked Keith Tanner's book "How to Build a High Performance Miata"; it covers a wide range of topics and is full of useful info about the cars. http://www.amazon.com/Build-High-Perfor ... 0760337055

I'm still unsure about running a safety cage on the street in one of these, but as it doesn't have a structural roof, a cage can be LVV certified without requiring an authority card.

SLYDIT · Post by **SLYDIT** » Sun Mar 09, 2014 1:18 pm

The NC (2005+)is a REALLY GREAT chassis and even in standard form would probably out handle a tricked up NA but they are still 15k plus, so over your budget .the NC uses a shortened RX8 chassis while the earlier NA/NB use essentially the same chassis save for the NB having upgraded running gear.

For your budget a 98 to 2001 1800 RS model would be a good start for a base purchase of around 9k, they have good brakes 6 speed box,and an LSD and 15 inch wheels . Then add safety gear then brake pads. Then tires then some trick suspension and wider wheels. The reason you need a hard top is that the roll cage will most probably stop the NB's glass window soft top from working. Running with a hard top on will be about two seconds a lap faster than topless.if the car you buy has a good top then you can sell it off to pay for upgrades

There is a crowd that makes a fiberglass hard top shell for racecars thats pretty basic and isnt as weather proof as a factory top but is lighter and cheaper.

http://www.trademe.co.nz/motors/used-ca ... 806191.htm

http://www.trademe.co.nz/motors/used-ca ... 411847.htm (allow $1100 for a hard top)

having said all that...this earlier NA 1800 may be worth a shot, it doesnt have the LSD or 6 speed box but the money saved could go to some nice wheels/tires and suspension.
http://www.trademe.co.nz/motors/used-ca ... 318098.htm again youll need to factor on getting a hard top for it.

SLYDIT · Post by **SLYDIT** » Sun Mar 09, 2014 2:29 pm

Hey i have a great idea!
Ian could sell his NA8 to Slowcoach and build an NB instead...Win Win . you can both thank me later! hahahahaha

Post by **jif** » Sun Mar 09, 2014 3:36 pm

There was a MX5 "party race" series in Japan , maybe try and get ahold of one of these nicely track specced NR-A models :]http://www.miata.net/news/originaleditions.html

http://minkara.carview.co.jp/en/userid/ ... /31082983/

On 9 March 2014 14:29, SLYDIT <mx5talk@mx5forum.co.nz (mx5talk@mx5forum.co.nz)> wrote:

Hey i have a great idea!
Ian could sell his NA8 to Slowcoach and build an NB instead...Win Win . you can both thank me later! hahahahaha

------------------------
RED '90 TURBO.
SCARING PRIUS DRIVERS SINCE 2002
http://www.cardomain.com/ride/264041/19 ... -5/page-6/

[Posted via external email]

BRM · Post by **BRM** » Sun Mar 09, 2014 7:06 pm

I think that's all some solid advice.

Having an end goal in mind is a good way to go about things,
You don't want to build a car to suit one set of rules
then have to change bunch of things that cost a lot of money to suit for the other set of rules you're working towards..
It's a huge fuck around.

But what you said

In my view, ideal sequence would be:
Safety (WOF, cage, belts, brake pads/fluids, bushes)
Reliability (clutch, gearbox, diff, fluids, belts, hoses)
Handling (springs/shocks, roll bars, tyres, brake rotors/calipers/lines)
Speed (weight reduction, engine power)
Aesthetics (go-fast stripes etc)

there,
Is pretty good way to go about things as a starting point

Slowcoach · Post by **Slowcoach** » Sun Mar 09, 2014 7:36 pm

Yes, great advice. Thanks all.

I've just finished building a house, so will need to wait a few months for bank account to recover before kicking off. This will give me time to clear a space in the 3 car garage that I can only just fit 2 cars in at the moment!

One last question (or a repeat of an earlier one) - roll cages - is there any consensus on 'best' homologated version or best fabricator (Auckland). I don't want to pick a random place and have them weld something up out of exhaust pipe...

See you at the track in a while.

BRM · Post by **BRM** » Sun Mar 09, 2014 10:07 pm

Chubb racing on the shore,

Or defiantly quest fab in silverdale

SLYDIT · Post by **SLYDIT** » Sun Mar 09, 2014 10:14 pm

Cant recomend a builder but just note that the height and shape of the main hoop is different between soft top and hard top cages as the roof heights are not the same. If you got a cage built for a soft top car. Chances are the hard top wont fit on. Go crazy googling images of "miata cages" and take them along to the cage builder.

Ian · Post by **Ian** » Sun Mar 09, 2014 11:19 pm

Motorsport NZ have a list of approved roll cage constructors on its website....its not exhaustive but is a start.
MiataCage.com has an example of cage costruction as an example. There are at least 3000 Spec Miatas which have been built in the States so there is plenty to google..
Slyd - your suggestion is appreciated though I'm surprised you didn't suggest I use my 2006 MX5 !!!!!! Brian Goodwin's 3 NC build threads did get me thinking, esp his ultalight yellow one!!!!!
To the OP, a welded in cage will give you more rigidity than a bolt in cage...weight is your enemy, lightness is your friend. Even with a roll cage ,bigger wheels etc my car weighs at least 100KG less than when it was new.

SLYDIT · Post by **SLYDIT** » Mon Mar 10, 2014 6:41 pm

the NC is going to explode onto tracks very soon. as they get under that 15K mark more and more will start tracking them. they are a VERY good chassis will excellent braking and enough room for decent wheel and tire package. the NC is going to be around 2-3 seconds faster around ost nz tracks than a similarly prepped NA or NB. TDR does factory ECU retunes that get the HP a good nudge too. An NC just needs some decent suspension,pads and maybe a wider wheel out to 17x8 or 17x9, (oh and an NC WILL need to be hard top only as the folding top wrecks any chance of having a MSNZ cage

Keith Jones · Post by **Keith Jones** » Sat Mar 15, 2014 11:01 am

Check out ShoresNZ Fabrications Ltd (Tim Ackers) at Westgate.
We just got a MSNZ spec half cage for the Levin for $897 inc GST.
This includes all the necessary paperwork for MSNZ homologation.
A full cage, including side intrusion bars, dash bar etc, is around $1800 - $2000.

warrior · Post by **warrior** » Sat Mar 15, 2014 1:02 pm

Can I please ask "why a mx5?" If you are not wanting to turbo the car etc there may be a lot better cars to use.

Don't get me wrong I love mx5,s (I have two) They are fun, handle great and are cheap.

But they are not fast.

Well let me refrase that....there are a lot more cars for the money you are talking about spending that will go a lot quicker.

If you have your heart set on a mx5 then go for it but there may be better options.

SLYDIT · Post by **SLYDIT** » Sat Mar 15, 2014 4:58 pm

warrior wrote:Can I please ask "why a mx5?" If you are not wanting to turbo the car etc there may be a lot better cars to use.

Don't get me wrong I love mx5,s (I have two) They are fun, handle great and are cheap.

But they are not fast.

Well let me refrase that....there are a lot more cars for the money you are talking about spending that will go a lot quicker.

If you have your heart set on a mx5 then go for it but there may be better options.

agreed. but there is an enjoyment you get from an mx5 that no ther car gives you. sure there are "faster" cars on the track but they are boring. and in an autocross they are super fun. i regularly get first in class and top 1/4 of the field overall at club days. and the cars that are beating me are $20K+ race cars.
if you want a FAAAST MX5 then something like Ians Na8 plus turbo will fit the bill. or build a NB to similar spec and save up for a turbo later down the track. there is no point spending any money on a Naturally aspirated tune as the engines just dont respond. they are not a vtec honda

Slowcoach · Post by **Slowcoach** » Fri Mar 21, 2014 10:54 pm

Re: nb8 2002 sport.... You mean something like this?

http://www.trademe.co.nz/motors/used-ca ... 567234.htm

SLYDIT · Post by **SLYDIT** » Fri Mar 21, 2014 11:43 pm

there is very little benefit buying a sport like that over a normal 98-99 RS. its just wasting money. the vvti engine isnt that much more powerful and is a pain in the arse if you want to go with an aftermarket ECU later down the track if adding a turbo or just trying a better tune. sure the sport has slightly bigger brakes, but the NB size brakes are FINE for trackday work.
stick to a 98-99 RS and spend the money on tires etc