MX5 on Carbs

[Cropper]

Hi, Newbie here with a question, I am just researching what donor to use for a roadster, I like the idea of using the MX5 but i would love to have the engine breathing through twin 40's or 45's, I love the sound.
Does any one know if anyone has done this?
All suggestions greatly recieved.

Neil:)

[jason 82]

I have not came across this before. I suppose best thing to do would be to fabricate an inlet manifold to suit the mx5 head, and your selected carbs, junk the ecu, and take the car to a rolling road to get the carbs set up correctly. It could take some time trying to identify the correct jet sizes. I think that you need to prioritise which is of more importance, mx5 engine or webbers. If you want webbers, go for a pinto. In my opinion, it will cost a lot of money and time, not only to get it all fabricated up nicely, but to get it running correctly. You may have an issue if you junk the ecu on a 1.8 as I believe the engine runs variable valve timing. Best thing would be to ring a company called race shak, based in Tewksbury Gloucestershire. These boys are amazing at stuff like this, and are also main dealers for omex. But it will cost you a load of wedge I am sure ! Happy hunting. :D

[Stot]

It can be done. There are people with bike carbs on the MX5 forums and they retain the ECU to run the spark. It doesn't get you more power the injection is optimal for power output.

If you want the sound a better bet may be to go for an individual throttle bodies setup and run a megasquirt ECU. Or chuck a crossflow on twin webers in there.

Cheers
Stot

[Cropper]

Thanks guys,a bit more thinking time reqd I think!

[Not Anumber]

When i was looking to build a Haynes one of the most convincing arguments for using the MX5 lump was the ability to use it's robust and efficient fuel injection system rather than having to throw money and time into sorting out alternative induction systems.

I am sure there are some mods you could make to the air intake / air filter to improve the induction roar without compromising performance.

[vmax1974]

Give me a supercharger whine and nice sounding exhaust

Just my preferance

[jason 82]

Stole my thunder vmax. Moss Europe sell a bolt on supercharger, everything included, just plug and play. :D

[Cropper]

Thanks for the comments, but i was brought up on Twin Cams & twin 40's, it's probably me just wanting to re-live those days!!:) It maybe that i end up with the stock injection system, i suppose it will depend on funds at the time! Maybe throttle bodies would be a reasnoble compromise?

[jason 82]

Go for throttle bodies, with trumpets & air filter socks. Or if you want to go real old school, when I first passed my test, I had an Astra mk3 injection. I was totally broke paying finance, so I pinched a pair of my girlfriends tights, ditched the air box, and pulled one leg of the tights over the airflow meter. Lol. Oh the good old days where you just didn't give a stuff ! Good days. :D p.s the tights were for the car, honest !

[Cropper]

If you say so!!;)

[Dualist]

Jenvey do an inlet manifold for it and as their TB's are the same mounts as carbs but the angle is incorrect so you could mod them.

Go for what you want mate, feck anyone else, it's your car you're building ;)

[PorkChop]

The stock MX5 inlet manifold is pretty good for an OEM item (as is the exhaust manifold come to think of it).

You wouldn't get much change from £500-1000 depending on how much you can do yourself to fit ITBs. So you're getting into the sort of budget that you could build a low pressure FI MX5 engine.

Another option is to look at Blink Motorsport's recently offered cylinder head & cam package over on MX5Nutz. £1250 + VAT for a worked and refurb'd cylinder head, hotter cams, wideband lambda and a PNP Megasquirt.