Air box

[jimj]

A pal is having a DB5 rebuilt and uprated at Aston Engineering in Derby. Yesterday we went down to see how it was coming along and ask gormless questions. These guys build engines for many of the more successful Aston racers so they must know a thing or two, have their own dyno. etc.
Their chief engine builder reckons a fast road 6 on triple Webers gains around 25 BHP with an airbox ducting cool air from ahead of the radiator, just like the standard set up in an Elan, compared with just bolting filters to the intakes and drawing air at under bonnet temperatures. That`s 25 on top af around 300 BHP so IF the proportion is similar on a twincam it`s a worthwhile gain.
Jim

[GrUmPyBoDgEr]

I agree that drawing cold air into the induction system will improve performance; it's been proved often enough.
The 25 bhp increase does sound optimistic however.
Rohan & others will probably have some more relevant facts regarding the "Twink"

Cheers
John

[bcmc33]

I?ve changed from ITG foam filters to an air box for my FI conversion on the basis that it is technically more correct to draw cold air from the nose instead of warm air from the engine bay. Theoretically there should be an efficiency improvement, but whether it will be all that noticeable, I?m mot sure.

Working on the DB5 figures ? it works out at about 12 BHP on my engine. The way I drive I think I?m more likely to notice the fuel economy more than the power increase.

What I?ve also done in an attempt to improve the induction cycle is to take-out the taper in the box that always seemed to be blamed for #4 pot being starved of air.