Mazdaspeed

[PaulF]

There are a fair few Roadsters in Japan running on carbs. I guess they're probably easier to work on at the track when you've got limited tools. Also, Warren Heath (wozzah1975) has a BP running twin Webers that makes about 150rwkW normally aspirated - partly because the manifold for the carbies has much better flow than a standard MX5 intake manifold.

[Aussie Stig]

I love how the Japanese will spend insane amounts on aftermarket parts.

Then of course we drool over them when they come up for sale secondhand.

[PhilM]

Thanks for the Eunos catalogue -there was a lot fitted to make a V Special Roadster that was not avail in Aus MX5s.

[thelaughingman]

anyone else got some stuff to share?

[hks_kansei]

There are a fair few Roadsters in Japan running on carbs. I guess they're probably easier to work on at the track when you've got limited tools. Also, Warren Heath (wozzah1975) has a BP running twin Webers that makes about 150rwkW normally aspirated - partly because the manifold for the carbies has much better flow than a standard MX5 intake manifold.

A pair of twin throat webers is pretty similar to quad throttle bodies as far as the engine sees it.
The difference is just in the fuel delivery, quads atomise fuel using injectors, carbs do it via airflow.

If you were really keen I'm sure you could fit a pair of sidedrafts and then machine a fitting into either the carb body, or the manifold, to fit injectors, then remove all the floats/needles/etc.
You'd then have the sidedraft look, and the ITB function. (well, assuming the placement of injectors that close to the ports doesn't cause issues?)

[thelaughingman]

If you were really keen I'm sure you could fit a pair of sidedrafts and then machine a fitting into either the carb body, or the manifold, to fit injectors, then remove all the floats/needles/etc.
You'd then have the sidedraft look, and the ITB function. (well, assuming the placement of injectors that close to the ports doesn't cause issues?)

That sounds far to complicated and expensive to be worth it for the gains, if that was the case it would be easier to get an adaptor plate to bolt to the manifold i have and run 4AGE itbs or even motorcycle units.

I wonder is there any motorcycle throttles that have the same bolt pattern as the the DCOE that might be an easier way, then i could still run injection.

[hks_kansei]

That sounds far to complicated and expensive to be worth it for the gains, if that was the case it would be easier to get an adaptor plate to bolt to the manifold i have and run 4AGE itbs or even motorcycle units.

I wonder is there any motorcycle throttles that have the same bolt pattern as the the DCOE that might be an easier way, then i could still run injection.

That's why I said if you were really keen.
It would be a lot of effort for no real gain over a normal throttle setup.

[thelaughingman]

That sounds far to complicated and expensive to be worth it for the gains, if that was the case it would be easier to get an adaptor plate to bolt to the manifold i have and run 4AGE itbs or even motorcycle units.

I wonder is there any motorcycle throttles that have the same bolt pattern as the the DCOE that might be an easier way, then i could still run injection.

That's why I said if you were really keen.
It would be a lot of effort for no real gain over a normal throttle setup.

I love the sound of ITBS and Carbs. I know that you dont see any real gains until you heavily work the engine but the noise just changes the whole experience.

[sailaholic]

Your both over complicating things. There are off the shelf throttle bodies to suit most popular carb patterns such as webbers.

The Jenvy kit might even use a standard bolt pattern, but I can't remember.


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[thelaughingman]

Your both over complicating things. There are off the shelf throttle bodies to suit most popular carb patterns such as webbers.

The Jenvy kit might even use a standard bolt pattern, but I can't remember.

yes but they have a hefty price tag too

Back OT anyone else have some mazdaspeed parts on there car?

[hks_kansei]

Your both over complicating things. There are off the shelf throttle bodies to suit most popular carb patterns such as webbers.

Well, the point wasn't really "oh it's an amazing thing, you should gut some webers and shove them on" it was more that if you really wanted, and had a big chunk of cash/time, you COULD do it. But it wouldn't really be worth the effort.

[Sikamikamiko]

Genuine Mazdaspeed Quad Throttle (IRTB) Kit to suit NA8

Hi there!

Anyone runnig these! How they feel On the road? Anyone selling by a mere chance? ;-)


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[sailaholic]

I run them. The exact ones pictured. Noticeable torque loss below 3/3.5 k. Much cleaner revving till red line.

For a daily it could get tiresome as the car struggles abit with hills or moving from the lights (particularly with ac on) with out appearing like your trying to race everyone.

I don't run the ecu or air box because my coolant reroute gets in the way of the air box and because I now have cams and headwork so didn't think the stock (mazdaspeed) ecu would cope.

I've thought about selling (twice) and getting Jenvy units seeing as I don't use the box and ecu... But I really can't be bothered and it would probably still cost money.


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[gslender]

It looks like it uses the NB injectors in the head. You might get better results if the injectors were closer to the butterflies which a Jenvey would provide.

I hope to have my NA6 with a NB8B and Jenvey ITBs going soon so would be interesting to compare (though I've yet to replace cams etc)

G


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[sailaholic]

Just ran standard na8 injectors to start with, but yes in the head as per standard na8.

The mazdaspeed units use a much shorter throttle body then the Jenvy units

The extra compression and variable valve timing should do a lot to help you also G.


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