Originally Posted by diamondjim
Can anyone tell me the pros and cons to the newer style snorkel opposed to the older flat style. I am looking at an older 4 and it has the flat style air intake. I was wondering if anything can be done or should be done with it. If so does anyone make a kit or can I just make a snorkel. Thanks
Sounds like your RV4 was built and fitted with a Bracket Air Filter from certified aircraft parts.
Many early RV4 builders (me included) had few options in the plans for Carb intakes and filtration as the now standard FAB Air Box wasn't designed yet.
The pre-97' standard RV4 Cowl had the small intake which required fabricating an aluminum Carb induction that fit the intake/"snorkel" as you call it. The "Flat" intake you're referring to is when several builders back in the day simply took an off the shelf Piper or Cessna Bracket air filter box and fitted it on their RV4.
I bet yours is one of these.
Later RV4 (post 1997) cowlings have a larger intake scoop to match the Vans FAB AIR Box intake system. The 0-360 Cowl has an even larger scoop. If I were you and it's running good, don't mess with success.
Cutting the lower cowl to install the scoop and Vans FAB AIR box will cost with paint around $1000 (or more) and may yield 1-2" of additional MP. You could also go with a Sam James cowl, plenum, RAM air intake and re-engineer your entire intake system.
If it were me I'd just spend that money on 100LL and enjoy it.
Early RV4 with the Bracket "Flat" filter intake set-up. (Savvy viewers will also notice the counter clockwise prop rotation from the LO-360E-1AD)
PS:Much of this corporate knowledge comes from building an RV4 but that's the beauty of this site, learn from others