MX5/Miata Thread

MX5/Miata Thread


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Suspense

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Do any of you guys have an after-market intake, preferably cold air?

Any thoughts on the various types and models available? I'm looking at options for a 2002 NB.

There's a lot out there that don't seem like they would be that useful (ie an open pod filter sucking in hot air right next to the engine...) but a lot of people seem to have them so surely there's some reason behind it? I would have thought something like the Racing Beat u-turn intake, boxed in to heatshield it would be preferred.
 

GaryC

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The only thing that works better than stock is to take cold air from outside the engine compartment. It's either intakes from under the windshield (MX5Mania CAI) or direct from outside (AutoEXE Ram Air Intake). Anything else just has the same issue with the stock one. Here's a good read too: http://autospeed.com/cms/title_FreeFlowing-a-Miata-MX5/A_110680/article.html

I've been thinking of this too, and if/when I'll be doing it, I'll be doing it the method of taking air under the windshield. But definitely not getting a Mania CAI. Bunnings should have all the stuff needed at a fraction of the price.
 
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Suspense

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If the intake is boxed in to the area just behind the left-hand side headlight, it should be protected from the heat of the engine bay, right? It's still taking in air from the same location as stock, but now shielded from the engine bay so in theory it should be just taking the air coming from that little pocked behind the headlight.

I'm confused by things like the K&N Typhoon and the AEM intakes. They seem really popular, but they're just sucking in hot engine air, and arguably worse than stock given they're actually close to the engine with no protection. They might let more air in but they're letting in a greater quantity of warm air.

Am I missing something?

The Mania-style intake would be great but isn't an option for an NB8B or later due to the location of the ABS unit. The SP Motorsports is the 'right' way to do it (a box located down behind the foglight, taking in cold air from the grill) but it's also a very expensive way (twice the price of the Racing Beat, 3-4 times the K&N Typhoon).
 

Lastsoul

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I was thinking about the RX7 AFM (Thanks for thel ink zephyrus17!) but apparently it's not a direct swap. Then I'd get cone-type filter, but I'd build heat sheat around it and direct airflow behind left pop-up lamp fitted with NACA duct to the filter. I haven't made any better plans yet, but that might be the best way to get cooler air with less restrictions. It would be mostly DIY parts except the filter and RX7 AFM to keep the costs down.
 

GaryC

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That link and other forums also mentioned having issues calibrating the RX7 AFM to work with the MX5. Personally, I think the differences aren't that big to justify the hassle of needing to recalibrate it.

Obviously the benefit of having the front facing intake is the fitment and not needing to drill a hole in the back......
 

thedguy

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I wouldn't touch the RX7 AFM. I've got one sitting on a shelf in my garage somewhere. If you can get it to run with decent power, it'll run rich as shit the rest of the time. I recall reading a thread about 1 guy who got it going ok, he soldered in 8 potentiometers to adjust the readings it gave on a dyno.

All said and done he spent as much as he would have getting a megasquirt trying to gain 4hp out of an rx7 afm.

BTW, if you want a better intake setup, look up "randall intake." Seems to be the way everyone's going these days.
 

GaryC

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Yeap! That Randall is the same as the MX5Mania one, taking air from behind the firewall under the windshield area. Drilling the hole is probably the only big issue.

From MX5 Mania:
ManiaCAI.jpg

I'm not too keen on the carbon fibre, though
 
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Lastsoul

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That looks like a pretty easy DIY project, I've to think about it. I'd guess induction noise is also pretty good when it's sucking directly under the windshield?
 

Suspense

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The Randall isn't an option, unfortunately, as there's no gap there for an Australian NB8B or later. In the pic above that zephyrus posted, that place in the firewall is blocked by the ABS system, and you can see to the right (where the Randall system goes) there's the wiper motor for RHD cars.

Bit of a bummer really as the cowl induction approach is a great one. So I'm back at looking at something like the Racing Beat system taking air from behind the left-hand side headlight.
 

MWF

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OK guys, help required (must get an account at Miata.net but in the meantime.....)

Right hand roof catch isn't closing the roof all the way, seems a but loose and leaving a 4-5mm gap but also looks like it is adjustable. Any clues as to how I can adjust the tension or where I might get this info?

Thanks.
 

GaryC

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That looks like a pretty easy DIY project, I've to think about it. I'd guess induction noise is also pretty good when it's sucking directly under the windshield?
Yeap! It's a well known high pressured zone that has a deep growl. But some people find it too loud. My intake currently makes a high pitched whistle above 2.5k rpm. Anything's better than that.

The Randall isn't an option, unfortunately, as there's no gap there for an Australian NB8B or later. In the pic above that zephyrus posted, that place in the firewall is blocked by the ABS system, and you can see to the right (where the Randall system goes) there's the wiper motor for RHD cars.

Bit of a bummer really as the cowl induction approach is a great one. So I'm back at looking at something like the Racing Beat system taking air from behind the left-hand side headlight.
Alternatively, make a tubing that takes in air around where the right (when looking at the car) baby tooth is. That could work.

OK guys, help required (must get an account at Miata.net but in the meantime.....)

Right hand roof catch isn't closing the roof all the way, seems a but loose and leaving a 4-5mm gap but also looks like it is adjustable. Any clues as to how I can adjust the tension or where I might get this info?

Thanks.
Can't you just adjust the little spinning knob on the thread? Your spring may be loose too.
 

MWF

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I saw that but it has a kind of plastic shield thingumy around it hence my question.
 

Lastsoul

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If somebody of you knows the address of that incabable guy who designed the lower A-arm, can you give it to me?

Ball joint is attached to lower wishbone with two bolts, smaller of them is in a small hole which access is restricted by the shock absorber. That makes the gap to about 18mm and the bolt is 17mm. Not a chance to reach it with a socket... If it were torx or some other type, it wouldn't be a problem at all. Now I have to remove shock absorber from the A-arm, which is quite a challenge with 18 year old bushing. It's totally rusted to the bolt and apparently no matter of reasonable opening techniques or unreasonable force and cursing (I've only tried in Finnish, English and German. Usually Finnish is the most effective) will make it slide out. :p
 

Posmo

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Yeap! That Randall is the same as the MX5Mania one, taking air from behind the firewall under the windshield area. Drilling the hole is probably the only big issue.

From MX5 Mania:
View attachment 4889

I'm not too keen on the carbon fibre, though
I just stubled upon this thread, but noticed this picture of the intake. My question is, how much does that intake system cost? Because I have the EXACT same air filter on my Sierra, and it cost me 15? new.. Piping is easy enough to do from plastic plumbing as the intake hole is exactly 4"/10cm, which is an easily found diameter.
 

thedguy

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The Randall isn't an option, unfortunately, as there's no gap there for an Australian NB8B or later. In the pic above that zephyrus posted, that place in the firewall is blocked by the ABS system, and you can see to the right (where the Randall system goes) there's the wiper motor for RHD cars.

Bit of a bummer really as the cowl induction approach is a great one. So I'm back at looking at something like the Racing Beat system taking air from behind the left-hand side headlight.
got pics of the engine bay in question?

You might try getting some flex tubing from a hardware store and running it down to the fog light area and having it feed air up to the stock air box location. I've seen that done, but no idea on the results yet.

If somebody of you knows the address of that incabable guy who designed the lower A-arm, can you give it to me?

Ball joint is attached to lower wishbone with two bolts, smaller of them is in a small hole which access is restricted by the shock absorber. That makes the gap to about 18mm and the bolt is 17mm. Not a chance to reach it with a socket... If it were torx or some other type, it wouldn't be a problem at all. Now I have to remove shock absorber from the A-arm, which is quite a challenge with 18 year old bushing. It's totally rusted to the bolt and apparently no matter of reasonable opening techniques or unreasonable force and cursing (I've only tried in Finnish, English and German. Usually Finnish is the most effective) will make it slide out. :p
I didn't have a problem with my car, and it spent many of it's former years in places that rust exist.

You do know you can replace just the boot and throw fresh grease on the ball joints right? You don't have to replace the joint itself if it's not worn out. I did exactly this to my tie rod ends and ball joints. IIRC I spent all of $30 to rehab all the joints on the front of the car.

Come to me when you gotta work on an e30. You have to lift the damn engine and use 15 extensions to get a 22mm nut off to get the control arms out, with non serviceable ball joints.

I just stubled upon this thread, but noticed this picture of the intake. My question is, how much does that intake system cost? Because I have the EXACT same air filter on my Sierra, and it cost me 15? new.. Piping is easy enough to do from plastic plumbing as the intake hole is exactly 4"/10cm, which is an easily found diameter.
285 australian loonies. No idea what that is in real money.

Most people I see get some kind of ebay intake. 90_mx on clubroadster does some seriously beautiful work to his NA. He went this route when he switched to MS
IMG_3616.jpg

link for more info

Oh and to who ever was looking at the RX7 afm option, everyone I know that ran it, got rid of it. 1 guy destroyed an O2 sensor (after 2 months), another destroyed a cat and fouled up all his plugs after 1 week +weekend at the track.
 
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Lastsoul

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Yeah, my dust boot is okay but the joint itself is loose. You don't hear it, but it failed the MOT and it had quite a lot of play to be honest. And finally I managed to get bolts out, it just needed a certain type of spanner modified with angle grinder to get the one inside the whisbone out. Now I only need to buy pickle fork tomorrow. I was expecting to remove the joint by hammering it a bit, it's already broken so no damage can be done, after pretty long hammertime I gave up.

And thanks about the info of RX7 AFM. It's nice to be able to avoid mistakes already made by other people :)
 

MWF

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I took the advice and fixed my hood latch.

Everything went better than expected. :D
 

GaryC

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I personally won't go even near paying that amount for an intake. Getting the parts from the hardware store is much cheaper. That's a beautiful engine bay, thedguy! *Hangs head in shame*
 

thedguy

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I personally won't go even near paying that amount for an intake. Getting the parts from the hardware store is much cheaper. That's a beautiful engine bay, thedguy! *Hangs head in shame*
His whole car is beautiful.

IMG_1723.jpg
dsc0249rb5.jpg
 
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