NA info for noobie

wot · Postby **wot** » Mon Apr 16, 2012 3:00 pm

Hi,
First time here so I may be asking q's that have been answered before but I've trawled through the last 6 pages of W S B & T stuff and have learnt a limited amount.
90 model engine #B6614495, so I take it that it is an NA6 ?
Running 185x60 14s on orig minilite type rims which I presume are 14x 5.5 ins with 45mm offset.
Although I've had it for 20 years, it's been hardly used for the last 10 and I've been in a diesel ford ranger (slow revving).
Now I've got the feeling that I want to drop the engine revs by putting 15in rims on it and 195x50 tyres (Ku31's?)
So if i want to buy some s/h rims I need to know:
Will 15x6 rims fit inside the guards?
Is + 45mm offset the max I can go to ?
Understand the pcd is 100mm. Correct?
With the rims being 4 stud are these fairly scarce out on places like E bay?
Will NB rims fit? (think their offset is 40mm?)
Any ideas on where to source ?

Any advice/info would be much appreciated

manga_blue · Postby **manga_blue** » Mon Apr 16, 2012 3:23 pm

90 model engine #B6614495, so I take it that it is an NA6 ?
Yes

Running 185x60 14s on orig minilite type rims which I presume are 14x 5.5 ins with 45mm offset.
Most probably

Although I've had it for 20 years, it's been hardly used for the last 10 and I've been in a diesel ford ranger (slow revving).
Now I've got the feeling that I want to drop the engine revs by putting 15in rims on it and 195x50 tyres (Ku31's?)
195/50r15 are effectively the same diameter as 185/60r14, so no change in revs/km

So if i want to buy some s/h rims I need to know:
Will 15x6 rims fit inside the guards?
Yes, within a normal range of offsets

Is + 45mm offset the max I can go to ?
I'd say go lower, around +35 to +40 is best

Understand the pcd is 100mm. Correct?
Yes, 4x100PCD

With the rims being 4 stud are these fairly scarce out on places like E bay?
No, quite common, also fit Civics, earlier Golfs, MR2s and a host of other cars.

Will NB rims fit? (think their offset is 40mm?)
Perfectly

Any ideas on where to source ?
here, ebay, gumtree, etc

Any advice/info would be much appreciated
I'd stay with what you already have. Original, light, cheap, probably the best setup for a stock road-going NA6.

wot · Postby **wot** » Mon Apr 16, 2012 3:41 pm

Thanks,
Yes, just realised that only dropping fr a 71.4ins circumference to 71.2 so that doesn't make much sense. So finding some NB 15 in rims is no good, unless I went to a 60 profile tyre and that would give a 76.1 ins.
Can you explain why a smaller offset is preferable.

I don't think you can get KU 31s in 14 inch so if I could get some cheap Civic /jazz 15in wheels which weren't too huckery looking, is this a goer or am I just stuffing up a presently good looking car. Suppose I just hadn't realised just how quiet other cars had got and now the idea of doing a 1200 km round trip next weekend doesn't grab me.
Have I lost the MX5 plot?

Postby **NitroDann** » Mon Apr 16, 2012 4:02 pm

People incorrectly understand and or incorrectly use english to explain offset often. Less offset is actually MORE dish. The more plus offset you go the less dish. The lower the offset the more dish, negative offset is stupid wanker dish.

Forget dropping the revs, Rev it. It wants to rev and so should you. Mine does 8000rpm+ every day. Although its modified. You shouldnt labour the engine. Really.

Stock NB wheels are very good in every way on an na6.

Dann

Postby **NitroDann** » Mon Apr 16, 2012 4:06 pm

If it helps to understand the space in the guards, with just a roll done, the stock guards can accomodate 15x9'' rims. Patrick bramston has stock but rolled guards and runs 17x8 and 17x9s to fit his V8 supercar spec brakes under.

Dann

Guran · Postby **Guran** » Mon Apr 16, 2012 4:38 pm

Welcome to the forum wot. I'm not totally sure I understand the problem you're trying to solve. It sounds like you're concerned about the noise level in your NA6 while using it for a very long drive, and you're attributing that noise to the engine revs you need to use in 5th gear at freeway cruising speed. I don't think changing wheels or tyres will solve your problem. Engine revs are only one source of noise in an NA6. My experience with long highway drives in my stock NA6 (including 1000km each-way trips), is that it is a noisy thing by modern standards. However, most of it is wind noise rather than engine noise (unless you have a cold-air intake or sports exhaust which can both create droning noise). You can cut the wind noise by driving with the soft-top & windows raised, or even better by fitting a hardtop ... but it's still a very raw experience (some say that's part of the charm). For long highway drives, I like to use in-ear earphones with an iPod to listen to music at low volume. It cuts the wind & engine noise almost completely and you don't get to the end of the trip with ringing in your ears. Noise-cancelling earphones are even better. I recommend you give it a try on your 1200km trip. Even better, look for some twisty roads to break up your journey and remind yourself why you bought the MX-5 in the first place.

wot · Postby **wot** » Mon Apr 16, 2012 9:16 pm

Thanks for those contributions and I hear what you're saying.
I've just got a low rev diesel hangover but it's also a bit worrying to see how far away I've moved from the feeling that I had when picking this car up from the dealer in 1990.
I'll live with the revs and see if I can get a bit of soundproof lining to stick in the hardtop for long trips.
Anyone done this sort of soundproofing?

Postby **NitroDann** » Mon Apr 16, 2012 9:25 pm

You need to do it under the carpet, doing it on the hardtop will only make it louder.

Dann

wot · Postby **wot** » Wed Apr 18, 2012 2:19 pm

[quote="NitroDann"]You need to do it under the carpet, doing it on the hardtop will only make it louder.

Can you explain because I thought that later hardtops came with a lining that was all part of the noise reduction "program"

Mr nanotech · Postby **Mr nanotech** » Thu Apr 19, 2012 2:19 am

NitroDann wrote:The lower the offset the more dish, negative offset is stupid wanker dish.

Dann

So when are you buying neg offset wheels to go along with your comment?

PaulF · Postby **PaulF** » Thu Apr 19, 2012 2:41 am

nanotech wrote:
NitroDann wrote:The lower the offset the more dish, negative offset is stupid wanker dish.

Dann

So when are you buying neg offset wheels to go along with your comment?

When are you buying some useful information to go along with your comment?

Mr nanotech · Postby **Mr nanotech** » Thu Apr 19, 2012 2:51 am

You should be pretty safe with anything from 1x6 +45to 15x8 +20 with appropriate tyres and very minor guard work. Sky is tge limit but tgose are tge sensible boundzries nost stick to on an na6 stock powered. Use willtheyfit.com to get an idea of sizing and comparison. On phone so this may come out as jibberish lol. The hit detection on my touvh screen is pretty poor lol

Postby **NitroDann** » Thu Apr 19, 2012 2:51 am

Show me a pic of NEGATIVE offset wheels that are anything but wanky looking.

Not low, not less than stock, negative.

Dann

Mr nanotech · Postby **Mr nanotech** » Thu Apr 19, 2012 2:54 am

Charlie dosnt look too bad and you were looking at the n2 flared car ty bought too remember. Good luck putting anything but negative on that and not looking wanky!