Weber selection and initial jet tuning

[blodi]

That's impressive! Gosh, I have to go back just to remember where we even left off with my settings.  I took the car for a quick spin last night and she is running really nice.  Hopefully I'll get a few miles...maybe an updated log this weekend. 

 

[blodi]

Drove the car into work today. Took a log over lunch so I'll load that up tonight.  Running the F2 140/240 setup.  Car is running great though! 

[blodi]

F2-140/240....

51618 by blodi, on Flickr

Looking back through the logs to refresh my memory i'm thinking we were closest with the F16 155/185..... I still need to block the accell circuit and see how it impacts the richness up front. 

Edited May 17, 2018 by blodi

[240260280]

I'm in portugal until Monday. I'll plot after that. Yes plug spill jets and increase main to get a/f below 13.7 on wot run from 3000 to 6000 rpm.

 

[blodi]

I plugged the accel circuit and put in 150 mains last night. I'll report back when I have a chance to drive it. 

[blodi]

OK, F2 150/240 and the accell circuit "blocked"....so....uh....that didn't do what we thought at all....  

52218 by blodi, on Flickr

[blodi]

I guess it actually makes sense reading this from Pegasus. I guess I'll put back in the exhaust jet...

"The accelerator pump dischage valve (also called the intake and exhaust valve) bleeds off some of the accelerator pump output back into the float bowl. This controls how much fuel is actually delivered to the pump jet. Once you have selected your accelerator pump jet size, you can use this valve to fine-tune the output of the pump. If the accelerator pump jet is a little too large, one of these valves can get you to a setting "in between" jet numbers.

Discharge valve sizing, similar to Weber jet sizing, refers to the bleed hole size in .01mm increments. The 40 discharge valve bleeds fuel back into the float bowl as if it had a 0.40mm hole. The 100 size bleeds like a 1.00mm diameter hole, delivering the least fuel to the jet. (The 100 size makes a 50 size accelerator pump jet behave more like a 46 size.) The 000 size has no bleed hole, so it forces all of the accelerator pump volume to the accelerator pump jet.

The closer your accelerator pump jet is to being too large, the larger the discharge valve required. The closer the jet is to correct, the smaller the valve required. "

[blodi]

I put a 65 exhaust jet in.  The one that I had in there did not have any marking on it. I think that's why I thought it was a 00. But it clearly still has a valve function to it.  I'll report back tomorrow. 

[blodi]

ok...just educating myself more....the value on the intake/exhaust valve refers to the hole that is on the side of the valve like this.....

I forgot my SD card in my home computer last night...so couldn't take a log this morning...but overall...still looks very rich. 

[240260280]

Yes, the value is the hole size.

 

When you press the gas pedal, a piston in the carb squirts gas in two directions. 

1. Through the Accelerator Jet hole and into the throat of the carb

2. Through the hole in the spill jet above and back into the fuel bowl

 

The ratio of the two hole sizes determines how much fuel goes each way. 

- When you have 00 spill jets, all fuel goes into the throat.

- When you replace the spill jet with a bolt, no fuel goes anywhere and eliminates the Acceleration circuit .

 

From you results above, it seems the large dip at the start is not caused by the Acceleration Circuit.

 

For a next step, keep the acceleration circuit bolted shut and lower the fuel level 2 mm.

 

 

 

Edited May 23, 2018 by 240260280

[blodi]

Accel circuit is blocked, still have the F2 150/240 combo in and I dropped the floats from 12mm to 14mm.  I also re-synced the carbs, the front one was out of whack after having everything apart.  Now, just waiting for a dry day and we'll see what's what. 

 

[blodi]

OK, F2 150/240 and the accell circuit "blocked" with the floats dropped 2mm to 14....

6218 by blodi, on Flickr