Si.G's NA6

[Si.G]

Hi everyone, never actually looked in the garage section on the forum before, I am guessing it is the place for people to post up build diaries and stuff, so I thought I would share my experience so far.

Basically I bought my Na6 for sprints, but ulimately I am heading for targa and forest rallying. You will probably notice that my choice of upgrades seem more towards sprints, but that will probably change at some point.

FYI all my pics are here http://picasaweb.google.com.au/sigratton/MX5# but I will add them to the post as I go.

So the story so far - swore I would buy a rally/race car that was already ready to go after building a car in the uk - started with a stock na6



I was a bit loose on the suspension so I put new bushes in - sourced from the uk, significantly cheaper than sets available here





Another early purchase was wheels and tyres - People seem to think R-comps are worth about 3 seconds on the sprints here, so this was a must. Got Toyo R888, will probably go for something softer next time, but they have easily lasted a season.



Also added a rollbar that changed the stiffness of the chassis massively, but still need more bracing at the back. Got a bucket seat to hold me in too.

[Si.G]

Had the usual issues with hitting the bump stops on the back, so that needed to be fixed - adding the new suspension mounts = 1 sec faster over 2.5km! I managed to find a pair of apexi top mounts, but had to get some machining done for them to work with my konis.




I did some diy bracing next, until I get time to take the subframe off and build a tubular brace, similar to the autoexc type setup. Now I know there has been some stick on the forum towards people copying designs, but I make no appologies, this took a fair bit of effort to make. Looks a bit rough, but man does it work



Headers and zorst where next, second hand no name headers and a buddy club spec 2 zorst. the headers, thankfully, turned out to be very nice in terms of fit and welding. The zorst was on sale at the buddy club distributors - turned out to be a bit of a mistake - it is super loud, so loud that the venue where I do my sprints have ask me to quieten it down, even though it is next the airport here in perth - so some work is needed.




To hear the noise, check these out

http://www.youtube.com/watch?v=qD7h3ArDJc4
http://www.youtube.com/watch?v=AIOF3S0OD0A - pops a flame out on this one

I have made a bigger slot in silencer for the zorst, which is better than the buddy club supplied one at crusing, but not as quiet under load, so I think an extra box is required. Plus I worry driving it on the road because of the noise.

[Si.G]

I'm ultimately heading down the irtb path, so an ecu was required. A MS pnp came up for sale in the states, cost me $500 AU delivered so not a bad price. Hooked it up with an innovate motorsport wideband. The ecu was as easy to fit as they advertise and it did start first time, so I was very happy. the wideband was a bit more fun - I don't particularly enjoy wiring!!



got it all installed though - I need to find a less obvious home for the ecu



I did some mapping with a friend to get the tune fairly close before dyno tuning. Got it tuned - could have done the tune easily myself, but had to pay someone to do it to get access to a dyno. It is heaps better now that is has been fully tuned. It was decent after live mapping on the road, but the difference is noticable now it has been dyno tuned. I would recomend the investment to others.

Two bits of advice
1 - do your dyno tuning with the bonnet down, the intake temps are higher, hence my tune goes a bit rich because of the reduced air density - I am sure people are thinking yeap knew that, but hay you live and learn.
2 - the MS pnp base map is for a turbo application, so rescale your fuel and spark table straight away to avoid wasting time tuning and the having to do it again.

[Si.G]

After the dyno run, I have realised that cooling is a problem, so I have made shrouding for the rad. Ultimately I want a thicker rad, but that will have to wait for now. I have also recently discovered the coolent re-routing that people do, so I will be looking into that soon.



Finally got around to fixing my accelerator pedal - it was broken when I bought the car (only taken a year to get is sorted). It is quite a fun job - I had to take the whole steering column out.



I got a bride seat rail to replace my temporary solution - turned out be super heavy and not very low at all - I was very disappointed, so I used parts of it to make my own rail. The seat is now bolted in really well and the feel through the seat of the pants is loads better. Not dríven the car in anger since, but I am doing a MX5 club auto test tomorrow, so hoping the better feel turns in to faster times



The most recent additions to the car are racing beat sway bars, these where fitted last week, so looking forward to trying them out tomorrow on the autotest.

[Si.G]

These guys are waiting in the wings. I am having trouble finding a manifold for them. The jap companies that did make them (Jubiride, etc) don't make them anymore and have no stock left. I might end up fabricating one. They are Ae101 throttle bodies. I can find an adapter for the toyota manifold, but I don't want to use the toyota injectors and stuff.



That's it for now, I will post more up as I get new parts or jobs done. I think I am going to tackle the rear subframe bracing next.

[Jeo]

Great write up so far. Keen to see more.

[broady]

Wow, this is gonna be an awesome diary. Yea, all the buddy club exhausts are fscking loud!!

[Si.G]

So I did the club auto test today - all the work of fine tuning the dampers and tyre pressures has gone out of the window. The sway bars have change the car a fair bit. It is obviously much better in responsiveness now, but took a few runs to dial in other stuff. I am happy with the result!!

My next job to have the rear sub frame off and to make some tubular bracing so watch out for that.

[wazman]

Looking to be a tough little car

I love the DIY stuff ! not everyone is made of money....."Built not bought" a great way to put some love into the car.

What brand are the bushes ?

[Okibi]

We need to shoot some video, it's a quick little car with a very skilled driver and a BLOODY LOUD exhaust.

[Si.G]

Looking to be a tough little car

I love the DIY stuff ! not everyone is made of money....."Built not bought" a great way to put some love into the car.

What brand are the bushes ?

The bushes are from flo-flex in the uk - http://www.floflex.co.uk

You can buy from ebay - http://cgi.ebay.co.uk/Mazda-MX5-Miata-Eunos-Full-Polyurethane-Bush-Set_W0QQitemZ390123143697QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item5ad526c211

Work out about at less than $400 for the full set!!

I have not had any problems with them and they were a decent enough fit.

Si.

[Si.G]

Finally got phase one of the house reno sorted, so I can spend some quality time in the garage. I have decided to sort out my rear sub frame bracing. Going to fit some solid diff bushes while I am at it. Anyway made a good start today. Got the car stripped down and the tabs welded on.

I need to get on with this because there is a club autotest in 2 weeks.





Now onto phase 2.

[PUR157]

How have you found the bushes Si.G?

Stiffer? more Compliant? OEM replacement?

You sound like you've got alot of practical experience to share...!

[Si.G]

How have you found the bushes Si.G?

Stiffer? more Compliant? OEM replacement?

You sound like you've got alot of practical experience to share...!

I have had no issues so far with the bushes, they are a fair bit harder than the OEM ones. One thing though, my car is not a daily driver, so although I see no reason why they would not last, I have not done any serious kms (approx 2000km). I have the suspension off right now and they all look fine.

Si.

[Si.G]

Phase 2 complete





Unfortunately I got one of my tabs a bit low, but with it being a be-spoke brace it is not so bad.

I am thinking about having 4 links to the floor rather than the more standard 2 (oem style). I am also considering linking this to the diff. I am getting some new stiffer diff mounts so I will see if it needs it.

Should have some more updates next week.

Si.