M20 RHD ITB’s to S54 air box adapters

[E30budget]

Hello r3v,

I am currently building and developing a few parts for my own M20 build. This is an adapter for the RHD M20 ITB kit to use the S54 CSL air box. This air box is a very well engineering part and I think it looks substantially more pleasing than the available RHD box. I plan to use the Karbonius CSL box - the original SMG box pictured was modified by Kassel performance and was used for testing purposes.

if anyone wants to also run this setup here are some things to note:

• This setup, with either a modified stock box or the Karbonius E30 swap box, should clear stock brake booster as the M20 head is much narrower than the S54
• You will need to plumb your vacuum system however you desire
• No clearance issues with RHD linkage system or throttle cable

These parts are designed to match the inner port diameter of the throttles AND the inner port diameter of the air box. The inside of the adapter has a tapered eventuri to not cause turbulence in the flow of air.

these will be produced of 6061-T6 aluminum and cost is $300 + shipping!

if anyone is interested shoot me a message with any questions you have - later June I will update this with other photos

[rturbo 930]

RHD makes an airbox specifically designed to be used with their ITB kit in an E30, and it's $385 extra. Your kit is $300 just for adapters, no airbox, to retrofit an airbox that is for a different engine and application. No offense, but what's the point of this?

[E30budget]

RHD makes an airbox specifically designed to be used with their ITB kit in an E30, and it's $385 extra. Your kit is $300 just for adapters, no airbox, to retrofit an airbox that is for a different engine and application. No offense, but what's the point of this?

Thanks captain obvious! The plenums are completely different in design, engineering, and aesthetically the CSL S54 box is substantially better looking.

that’s simply it. As I said, this is a project for my own car and I am simply offering it to anyone else who may want to do this. Not all of us are penny pinchers ;) don’t let the door hit you on the way out

thanks cap’n

[digger]

Interesting project, i have made a custom airbox before to suit m20 some years ago (refer to build thread) and have made plans to do a better/nicer one and fitted the e90 style booster to assist a bit due to the smaller OD.

Before you go further i would investigate the brake booster clearance as its an issue especially if the runners have any length to them which is what you want. The m20 head may be narrower but it is also more upright.

[E30budget]

Interesting project, i have made a custom airbox before to suit m20 some years ago (refer to build thread) and have made plans to do a better/nicer one and fitted the e90 style booster to assist a bit due to the smaller OD.

Before you go further i would investigate the brake booster clearance as its an issue especially if the runners have any length to them which is what you want. The m20 head may be narrower but it is also more upright.

I appreciate the input. However, I have taken measurements from the S54 swapped E30 we have. Furthermore, I will not be running the spacer that you have shown in your photo. The S54 air box trumpets are plenty long enough.

[digger]

I appreciate the input. However, I have taken measurements from the S54 swapped E30 we have. Furthermore, I will not be running the spacer that you have shown in your photo. The S54 air box trumpets are plenty long enough.

Just as long as you have compensate for the different angle of the engines. You can see below that on the e30 the s54 airbox is quite central not the case on the m20 even without the spacer after the throttles



the optimum length for a typical m20 is like shown with respect the factory booster and the downward curvature of the s54 style box normally results in number 6 having to be shorter to fit the shell of the airbox around





you can of course shorten number 6 to whatever but this may not be the best compromise.

Anyway im intersted to see how it turns oiut