rrragmanliam

My Feedback: (1)

Hi everybody, Hey I was wondering if anyone has ever tried relocating the exhaust pressure tap on a Norvell muffler. If you did, how did it work out. Also I've noticed that the tap is very close to the engines exhaust port. Is this important? Will I loose a sustantial pressure advantage if I move it farther away from the ehhaust port?

Darren

BMatthews

No real difference pressure wise. Muffler pressure isn't serious pressure like tapping the crankcase or similar. It's a gentle pressure that helps the delivery only. As such you can put it pretty much anywhere on a normal muffler. On tuned pipes I think it makes a difference since they are so long and the pressure waves in the pipe are repetitive.

But some mufflers are a little bit thicker at the point where the tap goes. Also you'll probably need to buy a metric tap of the correct size to tap the hole. And obviously find a screw to seal the other one.

combatpigg

My Feedback: (3)

Hi DARREN, I have installed a tap on a few mufflers. Since there isn't much meat to thread into, I don't run the tap in all the way, I want a tapered thread. The other thing is to work some epoxy into the threads. I have also had good luck installing a brass tube where a threaded fitting would not work.

BMatthews

For these small ones I wonder if you couldn't get away with a simple pressure seal. Use small 1/2A sized silicone tubing, drill a hole, smooth the edges, insert a 1/4 inch length of tube, force in a 1/2 inch length of 3/32 OD aluminium or brass tube so it forces the silicone to mushroom out and seal and then add your tubing run to the tank onto the stub of metal tubing sticking out. This is similar to the Fuji film cannister method but in this case I'd use a slightly smaller drill.

Try a similar install in a scrap of 1/32 aluminium or brass sheet to fine tune the drill size and method. A little oil will help you force the tubing into place.

flyinrog

My Feedback: (1)

Hey Darren, is it for looks? just dont like all the plumbing? cause if you move the nipple to the bottom of the muffler,or too close to the exhaust manifold, you would end up blowing spent fuel back into the tank...probably not a big deal with 1 oz tanks but ,,something to ponder...Rog

combatpigg

My Feedback: (3)

That's it in a nutshell, BRUCE. If you get too much pressure, then silver solder the end of the tube shut and drill a pin hole through it. I had to go this route with a piped super tigre .15.

BMatthews

Good point. You certainly want to keep any sort of pressure tap ABOVE the level of the top of the tank or fuel will syphon into the muffler at least until the engine is running. And I suppose a bit of old oil would enter a low positioned tube and get back into the tank but that's a small issue I would think. Once it's running it's a tempest inside the muffler.

rrragmanliam

My Feedback: (1)

Hello again. Thanks for all the input. Here's what I'm up against. As you can see the pressure tap runs right inlile with the fuse side. I want to plumb it so that it's inside the fuse. Once this thig is built the plumbing will be highly inaccessable. Ive never tried it but can you solder brass to aluminum? Also if I solder or JB weld a small screw into the old tap orafice, then file off the head so it's flush with the mufler will it hold?

Darren

flyinrog

My Feedback: (1)

Man, D.. I cant imagine a flushed screw being more than a thread thick, or that it would hold for any length of time,maybe with some serious threadlock, or a servo arm screw in some JB weld perhaps.......Rog

Bipe Flyer

I had the exact same problem installing an .061 into my Ultimate. I just used a small screw to plug the original nipple, drilled a hole and screwed in a brass one. It's a little hard to see in the picture, but the original nipple is on the left and you can see the head of the screw I used to plug it. It didn't affect the engine's performance.

rrragmanliam

My Feedback: (1)

Right on Bipe, nice to know it can be done easly. Hey Rog, I think you right. I was going to JB the screw in and then file the head off for a cleaner look. But on second thought I think I'll leave the head on.

Darren

meowy84

The method that Bruce mentioned I would imagine would work just fine since that is the very exact method that the muffler is tapped on my O.S. .10 CZ powered Kyosho buggy engine from the factory and it seems to work just fine.