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Ok so for various reason's I don't want to cut a hole in my hood. Our car is Busa powered therefore has quad throttles. So far I have been using rubber plumbing elbow's to locate the filter's to the side of the engine. It should also be noted that I have now ported these to make the transition much smoother and open up the volume. However I think this has made them more flexible and am not sure how well they'll stay contoured.
pic:
http://www.flickr.com/photos/30221154@N ... hotostream

These tubes are 2'' on either end and taper down to 1.5 in the middle. Busa throttle's are more or less 2''.

I have recently found different elbow's that I can make work. They are used for central vacuum plumbing. They are 2'' all the way. However they are a tighter radius I believe then the rubber ones. They have to be to clear the hood. I can run my finger inside the pipe and it will come out the other end to give an idea of the radius. I like the idea of solid tubes that won't flex and potentially close.
pic:
http://www.mistersweepervacuums.com/sto ... 0elbow-78/

Now without actually taking these to a flow bench in theory what am I better off with? It is my understanding that you want as straight a shot into the intake port as you can. However what about the added volume of the extra half inch or so?

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Deman Sr7 build turning laps once in a while

Whats the tilt angle of your motor? Whats the possibility of coming up with an insert to go between the carb and head?
If the cylinder bank is tipped off of vertical you would be putting the curve in the intake tract further down on the Z axis of the car than if the curve were before the carb which would lower the overall height of the system.
Might even be able to fit straight runners going into the carbs that way and mount a remote airbox right on the edge of the chassis.

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"There are times when a broken tool is better than a sound one, or a twisted personality more useful than a whole one.
For instance, a whole beer bottle isn't half the weapon that half a beer bottle is ..." Randall Garrett

Could you maybe use a silicon turbo tube.
They come in various sizes and bends and would probably stand up better than rubber.

http://www.siliconeintakes.com/index.php?cPath=4&osCsid=ec62caa42d8b57d59a5712ef50acbc79

Al

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Super Seven 3.4

I think your best bet is to fab an aluminum (or whatever you like to work with) plenum. Looks like you have the room, and I would be surprised if you didn't see a decent performance increase.

Something like these: http://www.google.ca/search?q=hayabusa% ... 24&bih=655

but built to fit in your space. The 4 runners into the plenum will give your engine more instant air giving better throttle response, and maybe give you cold air intake. Those cone filters aren't helping your power level at all.....

I would say there would be two easy ways to make a plenum for that car. Either way would be held to the TBs with small rubber hoses with clamps and the plenum would have an inlet on the front somewhere with a filter on it, or in the plenum.

1- take some short straight tube and go straight out from the TBs, and then bring the plenum over the top and make the plenum larger along the outer/bottom edge. The plenum would be curved to fit close to the bottom of the hood. These short runners would be better for HP gains. Really all you need is them long enough to get a hose clamp on them.

2 - take some mandrel bent 90 (or whatever angle you need to clear the hood and get lower) and then have the plenum be lower on the car. The longer runners should increase velocity and give you better torque.

Cheers.
Cory

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Build log: viewtopic.php?t=9291

I used this calculatorhttp://www.not2fast.com/gasflow/velocity.shtml I made a few assumptions:

1.6L engine
10,000 RPM
100 deg F

The difference in pressure drop between the 2 sizes is:

1.5" dia = 0.155 inches Hg
2.0" dia = 0.049 inches Hg

Unless you are racing and need that last 0.3% of power, I'd say it is fine with the 1.5" dia elbows. If you support the filter end with a bracket of some kind (should be done anyway) then the vacuum created should not collapse the rubber tubes. The numbers here are just an example based on the elbow size differences and not the elbows with filter.

Just an opinion.

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Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE

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I am actually working on an airbox for the car and these elbows will play a role in the design. Are those pressure drop's throw a straight tube or an elbow? I guess what I'm wondering is if the flow will seperate on the inside radius do you guy's think? My airbox will be similar to the turbo plenum's but it will sit more to the side of the engine and the filter I plan on using is this one mounted inline and close to the front of the inlet hose near the rad


http://www.google.ca/imgres?imgurl=http ... =128&ty=51

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Deman Sr7 build turning laps once in a while

Those numbers are for a straight tube. The site suggests that the Reynolds number indicates turbulent rather than laminar flow indicating to me that it may separate on the bends. This is for either the 1-1/2 or 2" elbows. Whether the smaller diameter with a larger radius bend is better that the larger dia with tighter bend radius? I have no idea.

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE

And don't forget my Cushman Truckster resto Locostusa.com/forums/viewtopic.php?f=36&t=17766

There is a small distance from the throttle plate to the actual port entrance where I would think the air could straighten out. I will finish the 2'' tubes off and try to make some more progress on the rest of the box.

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Deman Sr7 build turning laps once in a while