How critical is the length of the trumpets fitted to Dellorto 45's ?


I'm changing oval filters in the engine bay for a big cone filter within the nose cone.

Cheers
Paul G

The shape of the bell mouth is probably more important than the length, unless you have a very particular set up in mind. Usually, the longer the better for road use is a not bad rule of thumb, but don't get hung up on it if shorter ones mean everything fits better.

Cheers Si,

I have 85mm of space to fit them in so I was thinking perhaps 45mm trumpets if I can find some.
From the air box I have coggered up I have 3" flexi to the filter in the nose. No trumpets yet though.

It did run lumpy if stuck in traffic but I took it out Saturday and did some in town driving and the improvement
was immense. The traffic around my local town since the "inferno" near the market hill has now made it an ideal
test track for overheating problems. The detours can be chaos at busy times.

Once I get the trumpets on I'll get a final set up done by a chap that Mel (Rusty Nuts) recommended.


Cheers,
Paul G

Have a read of this

http://www.emeraldm3d.com/articles/emr-adj-length-intake/

http://www.emeraldm3d.com/articles/mar2012/

http://www.emeraldm3d.com/emerald-adjustable-length-intake.html

Might give some idea

Shape is important.

http://www.profblairandassociates.com/pdfs/RET_Bellmouth_Sept.pdf

Length depends on whether you're aiming for low down power or top end. But it starts getting quite complicated quite quickly! Length gives better low end (usually).

Thanks everyone.

Reading and digesting that little lot should occupy me for a while.



Cheers
Paul G

I wonder how many other people have saved that page I scanned in years ago?!

One other rule of thumb is to try to leave at least the width of the choke free above the bell mouth. So on the 45's you have, aim for a minimum clearance of 45mm between the open face and the air box wall. A few mm won't kill it dead however.