I got this in the mail today and thought it might be interesting to those contemplating a new air intake (CAI) pipe or carby "ram tubes" or "trumpets".

It's actually written for fans, but holds true for the exercise.

About 250kb

http://www.dairally.net/daihard/chas/Miscellaneous/IntakeCones2.jpg

From this you can see that if you are running 36m/s (nominal intake velocity) your losses would be:

21.6 x 21.6 x0.7 = 0.326kPa for an abrupt entry

compared to 0.023kPa with an exponential evasee.

Not much on the face of it, but people keep telling me that 0.100kPa gain using a pod filter is supposedly noticeable. :wink:

Hehe, funny you post that as me and my old man are in the process of making some fully rolled trumpets for the webbers on our Fiat :P we've just finished making some larger choke tubes too, woo can't wait to get this thing track ready.

Matthius

hmm webers - gotta luv them. Was running a set of 55mm DCOE Webers off my galant with the 2.6 astron engine, easy to tune, reliable as hell and worked a charm. In many ways they are still better than an EFI system with the ease and reliability. Now if the good old galant wasn't being turbocharged, then I woudl still be running hte webers.

Thanks for the info Turbo_Charade.

I was reading about an insert for Holley's that went on top of the carbi to produce radiused edges, (without starting an urban legend and without knowing the application) I think that they said it was good for an extra 10hp. So that is some indication of improvement.

Ken

Definatly, a carbi NA setup is cheap and 99% what a efi setup can be for most of their purposes. Turbo carburettor motors are a stupid idea, due to design.

My main point was just to show what sort of differences there was in engineering a part to suit the application, and to prove(as good as i can) how little effect a 0.1kpa pressure difference between a standard filter and a bigger throttle body has.