Intake manifold tubing

[FIntruder]

I will be making an intake manifold for my Suzuki Intruder 1400. The thickest mandrel bent aluminum "tubing" I can find is only .065 (1/16"). Should I look for thicker "pipe" or is .065" ok? The aluminum injector bungs that will be welded to this runner tubing are thicker, like .125" or more.

When fitting the injector bungs, how far recessed from the intake runner should the tip of the injector be? Is it important to have the injector aimed at the intake valves? Is there an angle relative to the intake runner that the injector should be? Space constraints may limit just how much I can dictate the design but if'n I can I may as well make it as Ninja as possible.

[SQLGUY]

A lot of the answers here depend on what your goal is. To be perfect and ideal, the injector does need to be aimed directly at the intake valve and be close enough that its spray doesn't spread much onto the head or other parts. To work, though, there's plenty of room for error. Consider that TBI sprays into the manifold way back from the intake valves.

For my bike I made the intake manifold out of copper pipe fittings which are a bit thicker than 1/16", but I think 1/16" would be plenty... Aluminum is usually more ridgid than copper. If it doesn't deform noticably when you squeeze it by hand, it should be OK.

For injector placement, I simply did the best I could within space constraints, the access I had to the intakes (rubber boots limited how close I could get), and to get the injectors aimed as close as I could towards the middle of the intake stream. My injectors are probably aimed further "down" than what would be optimal, and I don't know how perfect my X-Tau is, but the running results for the engine are pretty good.

[obxer]

This info is targeted more at cars, but you might find it a good read for initial info. But they do make mention of engines up to 18K redline

http://www.jenvey.co.uk/
http://www.dtafast.co.uk/Throttle%20bod ... #positions

If you search for similar terms as found on these pages maybe you'll find info specifically for bike systems.

[FIntruder]

Good info. Looks like my space constraints will work to my advantage. My engine redlines at 5,000rpm, should make 80hp/100ftlbs at the crank. Having the injector close to the intake valve and the throttle body close but not real close is supposed to work good with my combination. That is how I have room for it coincedentally.