Diagnose not enough jet vs not enough fuel

[Coyotemutt]

Y'all were right and I ended up pushing the boost up. But only because it didn't cost anything and there were no ill effects. Basically I'm finding out the limits of what I can do with what I have without spending any more cash.

So now I've experienced 16psi. The water-meth has completely removed knock, even though it starts to go dangerously lean after 11psi.

It sounds and feels amazing but I know I wont get away with it being lean once the temps come back up next summer.

How would I go about deciding if this is a jetting issue (which I probably wouldn't be able to solve) or the bowls simply running out of fuel?

[buguy]

Could you run it up into high boost and then shut the key off and coast to a stop, then check the fuel level?

[Coyotemutt]

Could you run it up into high boost and then shut the key off and coast to a stop, then check the fuel level?

I could probably do that but I think the bowls would refill on just the leftover inertia of the engine slowing down after shutoff.

As soon as I let off the gas, the AFR returns to normal.

[kangaboy]

So now I've experienced 16psi. The water-meth has completely removed knock, even though it starts to go dangerously lean after 11psi.

You have data? How lean are we talking here?

[Coyotemutt]

So now I've experienced 16psi. The water-meth has completely removed knock, even though it starts to go dangerously lean after 11psi.

You have data? How lean are we talking here?

It got as lean as 14:1 for a moment right as I shifted. 13.5 otherwise. The main jet comes in at 11.5 otherwise and holds steady through the whole powerband if the boost is around 11psi. With it turned up higher it leans out suddenly near the end of the pull.

I have no data logging. I'm 100% mechanical here.

[panel]

What fuel pump are you running again ?

[Coyotemutt]

A stock style Brosol unit that has been boost referenced and the pump pushrod has been sealed with an o-ring.

[buguy]

Oh. I assumed you were running an electric pump.

[kangaboy]

So now I've experienced 16psi. The water-meth has completely removed knock, even though it starts to go dangerously lean after 11psi.

You have data? How lean are we talking here?

I have no data logging. I'm 100% mechanical here.

Yeah I just meant do you have numbers, which you do, and scary ones at that. Did it not ping when you went that high?

[buguy]

Agreed. That lean, it doesn't matter if it's cold or hot. Better get a handle on it before your tearing your engine back down.

[Coyotemutt]

It actually didnt ping. It sounded like a solid "vroom"

None of that rattle in a can sound. I'll just turn it back down. I'm still using the 1.5mm needle and seat and I'm wondering if that may be the main issue but I'm not sure how to figure it out without just buying the 1.75 seat and trying it.

[Clonebug]

Your intake temps are pushing 220 degrees at 16 lbs. boost......

[madmike]

try an electric pump , increase fuel inlet N&S , ,, or go F.I. =$$$
or go draw threw w/a 4 barrel we all been there

[Coyotemutt]

Your intake temps are pushing 220 degrees at 16 lbs. boost......

I used the calculator you sent me before heading out. It was a 50 degree night, I entered 50% for my efficiency and got aboit 110 for intake temps. I didnt just crank it and run.

Presently just figuring out if the carbs simply cant provide a reasonable fuel curve above 11psi or if I just need to get the bowls filling faster.

[madmike]

That was always a problem for my Doce side draft carbs too, not enough fuel in the bowls,