'The Mouse' is in da house

[Code4]

Finally picked up my first MX-5 this week. NA8a, silver 5 speed. early 2000 build. 173K km, full service history including major service at 100K. New clutch and brakes 30K ago.



First thing was a wheel alignment and balance to get base obs. The tyre guy: 'One wheel was out by 40 and another was out by 25. 40 is a lot'. It certainly steers and rides smoother now below 100 kph. There is still some front end skittishness at the 100kph mark on rough roads. Wheels are 16x7 CSA's with orange Mullins hub rings. Probably the cause of the nvh.

Front tyres are new Hankook Ventus V2 205/45/16 on the front and on the rear, the same size Blue Streak Stilletos rear !!



Plans are to keep it stock for GT travels and cruising. May get more comfortable seats if the standard ones prove to bad on longer trips and an up to date head unit.

[Magpie]

'Stock' watching this thread

[Lokiel]

Hmmm, buys an MX5 > 5 years old, plans to keep it stock - we've all heard this story before

[Code4]

Wow called out already you guys are quick

[Code4]

The alignment specs. A huge improvement.

[speed]

Nice one! If you stay in this forum your car will become modified. Is only a matter of time before you are drawn to the power of the dark side

[Code4]

My paint & panel guy checked out the car.
No major damage repairs and no prangs.
The bonnet, right front guard and rear panel under the boot have been repainted previously. Otherwise its straight and original.
He was impressed with the resprays. He has done many of the show cars that live here in T-bar and knows his stuff. I was very relieved to get his report.

[Code4]

Last Photos.

[Zabinskii]

replace that radiator soon ;) looks like its on its last legs.

alloy ones are cheap from ebay and do the job well

[Code4]

Well finally had time to take the mouse out. Headed off to the local BP for a tyre pressure check. Luckily their pressure machine is within 1 psi of my own $75 Bushmaster 3 in 1 tyre gauge.

On the way some 'spirited' driving revealed a sudden lateral change in the rear CG... as if a 20 kg bag of cement had been thrown across the boot. No loss or change in vehicle attitude but a sudden weight transfer.

BP gauge revealed 18psi rear and 22 psi front ! I brought both (hot) up to 32psi which was 31psi on my gauge. The sudden weight transfer has now ceased.

This morning they are 28psi. Research here and over at the big pub reveals anything from 29 psi to 38 psi for 205/45-16 tyres on 16x7 rims.

Does anyone use the 4 psi rule ??
The rule:
At the starting point, vehicle loaded, inflate the cold tyres to the recommended tyre pressure of your vehicles tyre placard. Then to determine if you have the correct pressure for a given load check the COLD pressure again and note the reading.
Drive the vehicle for several kilometres on bitumen at regulation speed until the tyres have heated up to operating temperature. This temp will also be influenced by the ambient temp of the day and road surface . . . . but that's OK. That's what you're driving on.
Now, say after 15 minutes, check the tyre pressures again and compare this to the cold starting temps. Ideally the tyre pressure should read about 4 psi above the cold pressure.
If the pressure is more than 4 psi above, the tyre is overheating and more air should be added. This is because there is too much friction from the road surface and side wall flexing.
Conversely, if the tyre pressure is less than the 4psi allowable difference, then there is too much pressure, tyre pressure is high and needs to be lowered.

So do I go lower than 28 psi ?? I was thinking no.

[rascal]

If the pressure is more than 4 psi above, the tyre is overheating and more air should be added.

or you are driving it harder than expected...

I start at 26psi cold and then after the first session it is sometimes 34hot. I then bleed air, not add it, to get down to my desired 30-31 hot.

Cold air pressures are just a guide to get you to your desired hot pressures..

[Magpie]

The only way to correctly set hot tire pressures is to use a pyrometer.

http://www.yokohama.com.au/News-and-Blog/2013/September/How-to-set-hot-tyre-pressures-in-race-tyres.aspx

[Code4]

A few minor additions and purchases made.
Deleted the sun visors and filled the holes with eBay blanks. Vision is noticeably improved.
Fitted carbon miata seat belt extensions. It is certainly easier to reach back and put the seat belt on with them, however the auto rewind feature has stopped.
Purchased some Koni STR.T OEM replacement shocks and FCM comfort bump stops from Moss Miata. They will replace the 180K original shocks still on the car. Ride height will stay stock.

A big shout out for Toowoomba Muffler Kings on Ruthven street. I wanted a smaller rear muffler with a slightly more pronounced 'tone' than the stock muffler. They kindly trial fitted a few generic options and I picked the one that sounded best to me. They claim it is free'r flowing' than stock so maybe mileage will improve a little. My wife couldn't tell the difference but under open throttle it is definantly louder.

I'd looked at some of the US sourced mufflers and various forum suggestions, but didn't want to spend huge amounts of $$'s.

[MattR]

For your tire pressures for the road, between 30-32psi will be fine if you drive sedately to the servo. I ran my NA at 32 cold for the setup I had for the road on Khumo tyres.

Rascal and Magpie were overthinking it a bit talking about setting pressures for the track.

Best to check pressures every fuel fill if it is not a daily car and take note of any wear on the tyres, wearing in the middle faster than the edges, drop a couple of pounds pressure, both outside edges wearing faster the middle then up the pressures by a couple of psi.

Other wear patterns can mean problems with alignment.

[Code4]

Thx MattR. Yes the forum seems dominated by race and performance posts. So be it. Got to have a ceiling to aim for if you want.

30psi works atm but I will have to play with a few more changes. When I learnt to drive, new Ferraris and Maseratis had 70 series tyres so the low profile and +1, +2 practices are a new experience for me.