How important is cool air ducting?

[superherojohn]

I'm going to run a 18hp B&S Vanguard is my Max II if I ever get it built. The Vanguard is a replacement engine so the originial ducting needed to come out. The engine compartment is nice and neat at the moment and at least though the test / trouble shooting phase I am not going to put in the ducting so I can get to everything for finial adjustments. I'm a middle aged guy who will be happy bumming around, I'm not racing anyone. Maryland has hot summers but not desert hot!
OK so I know that the engine needs to be cooled but come on.. is all that tin really necessary? Is anyone running without it?

[Roger S]

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[MaximusII]

I'm going to run a 18hp B&S Vanguard is my Max II if I ever get it built. The Vanguard is a replacement engine so the originial ducting needed to come out. The engine compartment is nice and neat at the moment and at least though the test / trouble shooting phase I am not going to put in the ducting so I can get to everything for finial adjustments. I'm a middle aged guy who will be happy bumming around, I'm not racing anyone. Maryland has hot summers but not desert hot!
OK so I know that the engine needs to be cooled but come on.. is all that tin really necessary? Is anyone running without it?

My MaxII has no ducting! I have a 16HP Vanguard and the only thing close to ducting is the air filter housing!

[Bud]

I have the 18 HP B&S in my Max II, and no ducting. It runs fine.

[whipper-ag]

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How could ANYBODY not like this guy?

The Model Citizen

[Roger S]

what happened was I read "is all that tin really necessary? Is anyone running without it?" and made an ASSumption of myself he meant the "tin" on the engine itself, which is a no-no to run without.

[Hey_Dan]

The duct is only needed with the internal muffler.

[superherojohn]

I have never actually seen a Max II with a B&S engine so some of my questions my be a little simple minded.

Here is a link to richard's showing a 25hp Max with a ton for cool air ducting. To be honest with you, I didn't want to build it.

Welcome to Richard's Relics Parts for ATV's

[Raleigh Trainer]

The colder the air entering any engine, the denser it is, meaning the more oxygen it holds, meaning the more fuel it can burn, meaning the more power you can get at the same compression. Whether or not you achieve a noticeable gain on an 18hp B&S or not, I do not know, but it's not a question of whether or not an engine will work (as long as it's correctly jetted for whatever intake it has).

My new Max II has the ducting, which is basically a large plastic snorkel and a rubber vibration fitting attaching it to the engine. It bolts to the tub in four places to keep it from shaking all over the place.

It gets plenty hot under the lid, though the new Maxxes come with the internal muffler, as previously mentioned.