need ideas for an inline airbypass valve

[Belgian1979]

What it says in the title. But it needs to be small. and to be used for a 1/4 rubber line. Any ideas on how I could fabricate one myself ?

[Kevin Johnson]

Try looking at small coolant bleeder valves. Maybe they would work for you?

[Keith Morganstein]

What it says in the title. But it needs to be small. and to be used for a 1/4 rubber line. Any ideas on how I could fabricate one myself ?

I’d like to more about what you want it to do and how it will be controlled.

[Belgian1979]

Just hand operated. Once set during balancing.

[ZIGGY]

Pet store aquarium valve?

[Keith Morganstein]

Pet store aquarium valve?

The aquarium air valves will be the most reasonable and compact. They are made in metal (stainless or brass) or plastic.
However, they are 3/16 (5mm) if that won't do, search for 1/4 barb valve.

[n2xlr8n]

I'm not sure if this is what you are asking, but I immediately thought of the manual boost control bleeder valves we used on the Subarus.

[Belgian1979]

Pet store aquarium valve?

The aquarium air valves will be the most reasonable and compact. They are made in metal (stainless or brass) or plastic.
However, they are 3/16 (5mm) if that won't do, search for 1/4 barb valve.

Thanks didn't think of that. Will look into that.

[Belgian1979]

I'm not sure if this is what you are asking, but I immediately thought of the manual boost control bleeder valves we used on the Subarus.

Any picture/schematic ?

[digger]

so you have balanced the throttles but now you are you trying to adjust each idle bypass hose?

[Belgian1979]

so you have balanced the throttles but now you are you trying to adjust each idle bypass hose?

Digger, my ITB throttle bodies are very low profile DCOE types. These have joined bores (one shaft with 2 blades on them) So balancing one pair against the other is not a problem. However since the blades in one pair are joined they cannot move relatively to one another.
Due to them being low profile they do not have an air bypass hole.
Each cylinder always has minute differences in airflow and with the unisync balancing tool I have them within one stripe of another (which the manual says is the aim) but that's as far as I get with that. I need to be able to get further.

[allencr267]

Are they equal when you pull a .0015 or .002 in feeler gauge thru them, same drag on both sides of the blade, holding down on the throttle stop?
You might have to reset the blades or just twist it a bit, pushing the blades in opposite directions.

[Belgian1979]

Well I use a strip of paper with which I verify drag to verify them when I set at equal opening initially, but they do require balancing immediately after as they are out of sync at that point. I guess theres only so much accuracy in using a gauge of sorts.

I don't think the blades/axles can be bent as they are pretty sturdy.

[cjperformance]

Get on ebay and search mini ball valve. There are tons to choose from.

[digger]

so you have balanced the throttles but now you are you trying to adjust each idle bypass hose?

Digger, my ITB throttle bodies are very low profile DCOE types. These have joined bores (one shaft with 2 blades on them) So balancing one pair against the other is not a problem. However since the blades in one pair are joined they cannot move relatively to one another.
Due to them being low profile they do not have an air bypass hole.
Each cylinder always has minute differences in airflow and with the unisync balancing tool I have them within one stripe of another (which the manual says is the aim) but that's as far as I get with that. I need to be able to get further.

I also have DCOE throttles synced using a syncrometer tool that works on airflow not vacuum. I also have idle control vacuum tube and individual hoses to each runner so not a true individual runner. My throttle butterflies were synced with the idle valve shut but vacuum tube still in place. Doing it this way with perfect evenness in the butterflies my issues were during trailing throttle it would have exhaust popping and sounds telling me that there was something amiss (i.e. high vacuum low throttle conditions).I surmised that the airflow was actually not balanced despite the throttles being balanced almost perfectly as measured using the sync tool and that the idle system that allows a small amount of cross talking between runners was somehow responsible. I made adjustable valves for each individual idle feed hose using a threaded rod with conical surface machined in that adjusts in and out like a poor mans needle valve. I tried to readjusting using a vacuum gauge and the needle valves. Ultimately it didn't solve my issues so I ended up getting rid of the contraption as at the time I convinced myself it was not a distribution issue. If I were to do it again I would I would try something different, I would see if the problem persisted without the idle system at all to ensure no cross talking.
The engine drove beautifully everywhere else, idled perfectly except one spot just off idle that would show up under trailing throttle (light cruise was fine)