Annular boosters on a Tunnel Ram
What I was trying to answer with this test was this. How does main air bleed size affect when the main circuit starts flowing fuel? Foolishly I thought this shouldn't take long to figure out.
My thinking was at first to check with no load on the engine. I tried .025 ,.035 and .045". Thinking big steps should show big changes and a clear trend.
The plan was to watch the booster with one eye and the tach with the other eye. Open the throttle until I see fuel dripping from the booster and note the rpm. Simple. I was surprised to see the rpm remain constant.
So I thought I could force a change. Next I put the .025 back in with .015 tag wire in it. Still the booster flowed at the same rpm. Next I took the main air bleeds completely out. Same result.
I thought maybe I need some load on the motor so I put a constant load on the motor and repeated the test. .025, .035 and .045. same result but at a lower rpm. Next I tried more load. Lower rpm same result. By now it was way past bed time and I gave up.
It would be my luck that I picked the one combination that could give these results. I will try this test again when the opportunity presents itself with another carb/ motor. Meanwhile is there someone who would be willing to try at least the unloaded version of this test on their motor in their car. I'm curious to see what your results are. It shouldn't take long. lol
I wasn't tuning this carb to this motor. I only picked it because it already had adjustable bleeds and no choke horn so the're easy to get at.
What I was trying to answer with this test was this. How does main air bleed size affect when the main circuit starts flowing fuel? Foolishly I thought this shouldn't take long to figure out.
My thinking was at first to check with no load on the engine. I tried .025 ,.035 and .045". Thinking big steps should show big changes and a clear trend.
The plan was to watch the booster with one eye and the tach with the other eye. Open the throttle until I see fuel dripping from the booster and note the rpm. Simple. I was surprised to see the rpm remain constant.
So I thought I could force a change. Next I put the .025 back in with .015 tag wire in it. Still the booster flowed at the same rpm. Next I took the main air bleeds completely out. Same result.
I thought maybe I need some load on the motor so I put a constant load on the motor and repeated the test. .025, .035 and .045. same result but at a lower rpm. Next I tried more load. Lower rpm same result. By now it was way past bed time and I gave up.
It would be my luck that I picked the one combination that could give these results. I will try this test again when the opportunity presents itself with another carb/ motor. Meanwhile is there someone who would be willing to try at least the unloaded version of this test on their motor in their car. I'm curious to see what your results are. It shouldn't take long. lol