Big Bore/Over Bore Throttle bodies - 1.8

[hamish71]

Does anyone know of a supplier for over bore (at least 57.5mm) throttle bodies for the BP engine, or a supplier who can bore the existing throttle bodies. Preferably in Melbourne.

[irwin83r]

http://www.mx5cartalk.com/viewtopic.php?t=29143

[hamish71]

Yes, have seen that thread....note that \"Woo\" did this himself, and is not a \"supplier\" as such. I have been chatting to him about the options.

I was hoping that someone could verify whther there was a melbourne business, such as efi hardware, had done this sort of work for mx5s before.

[hamish71]

FOr the record, EFI Technologies in Mitcham will do this work.

[CT]

What exactly will they do? I know they will modify stock manifolds and turn them into quad manifolds etc etc - fill us in mate?

[hamish71]

lol....CT...sell me that engine at a good price, and I might tell you!

EFI Hardware will overbore the throttle body by 2.5mm, and put in a new butterfly. I havnt got right down into the detail, the shape of the venturi so to speak, but yes, they gave me a quote for this work, no problems. If you go to the big forum, or look at solo miatas site...you will see he got a significant gain for an n/a engine (remembering for us n/a types, a significant gain isnt much!).

Ive had my cylinder head, intake and throttle body on a flow bench, and for you turbo types, the restriction is in the throttle body. If you are racing...I would highly recommend you do something here....like, adapt a 60mm throttel body. FOr street types, I think any bigger than 57.5 might create some issues.

[Steampunk]

what kind of gains are we talking about Hamish?

I want to slowly and steadily do up my engine and avoid the dark-side of artificial aspiration

[CT]

Sadly for racing, the rules prohibit us modifying the throttle body on a turbo car. Hi flowing the turbo and modifying manifolds is also illegal. But for NA, sounds promising.....

Is your head flowing more than 250hp yet?