Duct Fun (NGC)

[geodoc]

Just for a little burst of winter wild-ass. Friend Tom Mellor is modifying his Triumph Trident salt-flats record holder for this next year's BUB event (my shop space is a little nook in his shop).

The trick now is an airbox that will (1): provide ambient temp air to the carbs (2): increase the pressure at 170 MPH+ to (hopefully) about 3/4" MAP above station pressure. (3): I'm sworn to not blab about #3.

Pink stuff is a form for laying up fiberglass on top of for construction of the inlet 'S' duct. Inlet mouth is machined out of a solid block of aluminum.

He'll be in the 1000cc class this year (in 750 partially streamlined pushrod gas last year) he did 180+ in 2008 and is hoping to break 200 this year.

Subtle Crowbar .............. the gauntlet is getting thrown down! The Canadians are coming and they're going faster than 99 motherf****rs!

 

[geodoc]

Here's the finished intake duct and airbox plenum with tricky low pressure compensating door.

 

[guzzigray]

Beautiful work. Say hi to Tom for me and good luck.

 

[geodoc]

I will.

BTW, the air filter is from a house furnace.

Shocking .......................

Beautiful work. Say hi to Tom for me and good luck.

 

[Chris R]

Beautiful work as usual George. Designing airboxes is I think a bit of a black art - I've seen some that look like they should work well but didn't and vice versa. How are you going to test it?

And did you vent the float bowls to the plenum? Again finding the right place to stick the tap is a bit of a trick. I tried to sort one out once with a buddy and well we never got it to carburete correctly.

I think it would be easier these days as digital manometers are really cheap. If you are really cheap motorola make a pressure tranducer that is referenced to sea level that is both cheap and robust - we use the MPX5010. Available at Digikey for 15$

 

[geodoc]

Heh Chris,

I should clarify - the duct work was fabricated by friend and garage-mate Tom Mellor's Bonneville record breaking T150 Trident.

He's planning to test it out in Seattle at a guy's dyno that supposedly has a blower set-up that can simulate a 150 MPH airflow. His hope is to see if at that speed the pressure in the airbox will at least equal or better yet, exceed atmospheric pressure. Looking at what the by-pass door does on the airbox should give some indication, but an actual reading of the pressure would be better of course. I believe Tom is planning to use a water manometer for the dyno run to get an idea. I wonder whether an airplane altimeter would work nicely. At the salt flats there's no room for instrumentation though.

Beautiful work as usual George. Designing airboxes is I think a bit of a black art - I've seen some that look like they should work well but didn't and vice versa. How are you going to test it?

And did you vent the float bowls to the plenum? Again finding the right place to stick the tap is a bit of a trick. I tried to sort one out once with a buddy and well we never got it to carburete correctly.

I think it would be easier these days as digital manometers are really cheap. If you are really cheap motorola make a pressure tranducer that is referenced to sea level that is both cheap and robust - we use the MPX5010. Available at Digikey for 15$