use of air trumpets?

[mat777]

Whilst I continues my long and probably fruitless search for the right bit of adapting pipework (http://www.pistonheads.com/Gassing/topic.asp?h=0&f=140&t=1126673&nmt=Air+intake+suggestions%3F) to connect my new carburettor to the OE air filter box on my Land Rover, I have been forced to look for a more "boy racer" alternative for the meantime. due to the location and orientation of the carb, a pancake wont fit under the bonnet and all the cone ones are very expensive or have the wrong fitting. It was then I noticed you can buy straight trumpets with just a fine gauze on the top relatively cheaply.
Now, as mine is not a racing engine, and I dont wish to be rebuilding it any time soon due to dust ingress, do these providee satisfactory filtration? If not, I presume one can stick a lump of foam over the top like you see on some old F1 cars?
Also, a friend who has a max power filter can on his land Rover as a temporary solution advised me that with significantly less restriction there would be a fruity sounding intake roar - is this right, and if so will it be embarrassingly loud?

thanks,

matt

[davepoth]

Trumpets really don't filter much at all, and I've heard bad things about socks. If you are going to offroad at all it's a definite no-no; most people I know with them tend to only use them on track.

I reckon you would be better off using a bit of plumbing pipe (which happily can be found in 32mm, which is the intake diameter on the HS2 carb you've got give or take a bit) with a K&N filter or similar attached to the end. That way you can locate the air filter anywhere you like.

[lowdrag]

Well, the old fashioned way was a trumpet and some tights doubled and held on by an elastic band. Kept the dirt out and made the other access quicker!

[mat777]

Thanks for the advice guys.

Do tights provide adequate filtration against road dust?
Also, what bad things have you heard about socks? I was thinking about one of those pipercross sponge blocks for road use, that I could remove and replace with a length of flexi hose across the engine bay to the original oil bath filter before off roading

Thanks, Matt

[lowdrag]

I went from stone-guard wire mesh filters on my Webers to socks, and the spitting back caused the foam to disintegrate and the motor swallowed and burned the sock, so I went back to the wire mesh filters. I've never had a problem over the years, the use including touring and track use. Back in the days, tights were often used and were very efficacious.

[Shoestringracer]

I had foam socks which I sprayed with a special sticky spray. No idea what it was called. After one particularly dusty rally I washed the socks and the water was very dirty so they must have stopped some dirt getting in. However, there would also be visable dirt in the trumpets so they didn't stop it all!

[C8PPO]

A foam filter with filter oil over the trumpet will do it - this is what's used on all the dirt bikes. Needs a regular wash and re-oil though.

[mat777]

I dont mind the regular maintenance, and the vehicle does sod all miles these days anyway. I think based on these replies, I will go down the trumpet and sock route.
As for the spitback - this will be going on an SU carb so there should be no spitback as there are no jets like a weber.

A friend is still telling me that I;ll get a very loud induction noise from it though, is this true? I thought it only happened with those halfords cone shaped jobbies?

[aw51 121565]

Yes, it will hiss; whether you'll be able to hear it when driving I don't know (but it's not a 'nice' sound like a brace of webers is). The air filter and casing and pipework are all designed to minimise/banish this noise, but what you're proposing will still remove some of it .

[vpr]

I use these on my old Datsun....I know they're not great though they are finer than the pics show, its not just mesh its kind of triple layer

[Jacobyte]

For the road, I use K&N filters over the trumpets, like so: