MX5 MK3 / MK3.5 Owners

Amps · 14 Feb 2012 at 09:23

I recently bought a 2.0L Sportech MX5 Mk 3.5 NC, this car has recently had its clutch changed by the dealer (not mazda). Not having a massive amount of experience in rear wheel drive cars I notice that the following and would like to know if these characteristics are normal for this car.
• Diff noise at low speed (mechanical noise , appears when pulling away , disappears about 1.5-2k revs)
• When driving perfectly straight the rear end likes to try and overtake the front on damp (not wet roads) when giving it beans this happened twice this morning causing the TC to kick in at around 30mph.

And yes i will ease off in the wet

Dup · 14 Feb 2012 at 09:36

I haven't had much experience with the MK3, but are you sure it's the diff and not the gearbox? Remember compared to an FF car, you're actually sat on the transmission and you can probably hear that. Diff noise might be an acceptable if it has an LSD and an LSD may explain your second issue to a small degree. I would look into getting the gearbox and diff oil changed to see if that makes any difference.

For point two I would look at your tyres. Are they of a decent brand and are they near the wear markers? The weather recently has been exceptional in that it's been raining but so cold it's been freezing up the roads, this can make the car behave quite weirdly. I had a similar indecent to yourself in my MK1 the other day but I also have quite worn rear tyres which were the main contribute.

Amps · 14 Feb 2012 at 09:49

Tyres have a good 4mm/5mm on them front and rear, but are rather poor Bridgestone Potenza's , RE040's. (I will check exact model) it was 7C/8C when this occurred this morning.
I was kind of taken by surprise as I didn’t expect it to kick out so violently that it engaged the TC , I assumed that the diff would reduce the instance of this happening.
The noise may well be the gearbox it appeared to be coming from behind the driver so I assumed it was the diff.

Conscript · 14 Feb 2012 at 10:31

I have a 2006 MK3 2.0 with 6-speed box and LSD.

There only time I've thought Ive heard noise from the transmission is on long motorway drives - thought I could make out a kind of very faint mechnical buzz, although it could just be me. It hasn't caused any issues, and Ive had the diff/gearbox oil changed. That said, with the roof up, the car is quite noisy, and the confined engine/road noise is more noticeable than anything else when at speed.

As for stepping out, I've had very few problems with the TC kicking in. It's only been an issue when booting it out of roundabouts and occasionally when coming out of my workplace (although thats probably more due to a dodgy road camber and the fact that our lorries are probbaly spilling diesel than anything). Even on the now wet and greasy roads following the snow melt, the car is very stable and confident when accelerating and it's certainly isn't coming on regularly. For comparison, I am currently running Toyo T1-Rs all round since August, but before then the car was shod with Bridgestone RE040s on the rear. The T1-Rs feel better, but even so, the RE040 rarely gave me the same problems you are describing.

I would suggest having your suspension geometry looked at by a specialist. I had mine looked at by Wheels in Motion in Chesham who are renowned for the work they do with MX5s. My car was transformed after visiting them (although I had shorter springs fitted at the same time), but others in the MX5 community have also said what a difference a decent geometry setup can achieve.

Siliconslave · 14 Feb 2012 at 10:35

I've had a bit of noise from my gearbox / diff - apparently its normal for the 6 speed box it uses.

As for kicking the back out it will happen, but it shouldn't be happening too much unless your really flooring it, the tyres are useless or the road surface is really icey.

For comparison in normal driving the only time this has happened recently was when the roads were properly iced over, accelerating in a straight line caused the back to step out and TC to kick in. In damp conditions i have to properly work at getting it to break traction...

I'd be inclined to get my tracking looked at & check that the tyres are the same size (garage managed to fit the wrong size tyre to my car a while back and it has a very odd effect!)
Is this

grimm · 14 Feb 2012 at 10:40

Not noticed any problems with my 3.5.

The back end has swung out a few times when accelerating from 0 or slow speeds at junctions/tight turns but that has been due to the conditions, and I haven't noticed the traction control kicking in at all. No problems at all when the car is straight unless it's been really icy.

When it has been icy on the roads I have been pleasantly surprised really as it's handled pretty well as long as I avoid side streets.

sovietspybob · 14 Feb 2012 at 11:39

MK3 2.0 here and never had any transmission/drivetrain noises so far, had it from 16k now at about 42k on the clock, ours has the LSD aswell.

They can be quite skittish and nervous without a proper geometry done. We noticed a massive difference when we took ours to WIM and had it lowered and a full geo, it used to sort of 'shimmy' going into corners and inspire no confidence atall. Also the traction control light would be flashing a lot pulling away from junctions and on roundabouts. Almost all that stopped after the alignment and lowering.

I still find it has overall moderate grip compared to something like my subaru but thats to be expected, it is however perfectly balanced so you can have maximum fun with the avaliable grip and not be doing silly speeds to have some movement. But i've never had it step out of line unless i was provoking it.

Amps · 14 Feb 2012 at 11:41

This was a lightly damp road both times , fairly sure it wasnt cold enough for ice to form. I will get the car booked in for a geometry looked at. My concern was that there might be something up with the Diff related to having the clutch replaced.

Conscript · 14 Feb 2012 at 12:01

Amps said:
This was a lightly damp road both times , fairly sure it wasnt cold enough for ice to form. I will get the car booked in for a geometry looked at. My concern was that there might be something up with the Diff related to having the clutch replaced.

That would be a good first step, as a geometry setup can improve the handling immensely.

Can I ask, how does your car react to high speed? When I first bought mine, I used to the find the front end would tender to wander somewhat on the motorway at abouth 70MPH - quite disconcerting. A commonly reported problem which disappeared after a geo setup. If yours does this as well it might back up the conclusion that your geo could do with some attention.

Amps · 14 Feb 2012 at 12:40

I can't say i noticed a handling issue at mororway speeds the only issue has been in the wet when pulling away. The rear end of the car wants to overtake the front. Which is kind of disconcerting

BigshotPie · 14 Feb 2012 at 13:04

I have the MK3 2.0 Zsport and experience the same diff/transmission noise (coming from the rear) and beleive this is normal - my old mk1 and 944 used to make a similar noise also.

The second point is likely to be down to geometry, so find someone local that can sort this - I went to WIM and the difference was certainly noticeable afterwards. (I presume you've also checked the tyre pressures?)

On the tyre front I can whole heartedly recommend Michelin PE2's for your next set if you enjoy the cars handling - absolutely brilliant on my 5. I have since changed to Toyo T1R's (in bid to save money - as they are nearly half the price) and I have to say they are not even close, but I guess you get what you pay for!!

Lastly; Turn the TC off

Conscript · 14 Feb 2012 at 13:08

I've found the T1Rs excellent so far, if a little soft. Can someone describe the transmission noise? I can hear a slight chapter at idle but I hear that's normal.

BigshotPie · 14 Feb 2012 at 13:17

The transmission/diff noise, won't be at idle. The noise occurs when moving/pulling away slowly at low revs up to say 2-2.5k - I can only describe it as being a gritty/grindy/mechanical type sound which comes from the rear.

Siliconslave · 14 Feb 2012 at 13:19

oh, mines more of a metallic rattle - i thought it was a loose heat shield originally

Conscript · 14 Feb 2012 at 13:36

BigshotPie said:
The transmission/diff noise, won't be at idle. The noise occurs when moving/pulling away slowly at low revs up to say 2-2.5k - I can only describe it as being a gritty/grindy/mechanical type sound which comes from the rear.

Im hearing something different then, an irregular kind of chatter, is that what you get Silicon? I might try and get a recording one day.

Siliconslave · 14 Feb 2012 at 14:27

Conscript said:
Im hearing something different then, an irregular kind of chatter, is that what you get Silicon? I might try and get a recording one day.

yer, pretty much. Seems to be most prevalent when pulling off without too many revs. The best thing i can describe it as is a metallic rattling but its sporadic at best after nearly 8k miles...

Amps · 14 Feb 2012 at 14:30

BigshotPie said:
The transmission/diff noise, won't be at idle. The noise occurs when moving/pulling away slowly at low revs up to say 2-2.5k - I can only describe it as being a gritty/grindy/mechanical type sound which comes from the rear.

That is exactly what i hear. Only occurs when moving off at low revs or if you try to drive off in to high a gear

Amps · 14 Feb 2012 at 14:32

i dont fancy turning the TC off just now until i get to the bottom of this as without the TC on today i may have binned it.

Sin_Chase · 14 Feb 2012 at 14:34

Amps said:
Tyres have a good 4mm/5mm on them front and rear

I would not call 4-5mm good. Legal, yes.

I look at changing the tyres on my S2000 at 6mm where wet performance starts to become a concern.

The rear is going to lose traction in damp conditions if you are giving it loads, fully expect TC to kick in.

Conscript · 14 Feb 2012 at 14:55

Amps said:
That is exactly what i hear. Only occurs when moving off at low revs or if you try to drive off in to high a gear

Aha! I think I know what you mean now. Ive heard it too, I figured it was simply a symptom of the engine being under too uch strain when accelerating hard while still in a higher gear or pulling away with too little throttle.