Vaporizing Fuel w/my Device... Results...

[mderoy340]

Thank you.

By the fuel curve base line, do you mean the acc pump cam lobes, and power valves the same? If so, no they weren't. I had the orange cam lobes on the 750 and the pink ones on the 650, also, I have adjustable linkage on the secondaries that was pulling the secondaries open sooner on the 650. Everything I know of points to more power on the 650 run, but it was lower. I can't for the life of me figure it out. Does it seem to you that the 20* would drop my hp or increase it? I just finally got the timing chain changed, but it still had the power I had when I first set it up 6 months ago in summer, albeit not quite as much, it was still more than the 750 set up it seems like. Maybe I need to get the 750 running with the same set up I had it at and see one run after the other if the 750 has more than the 650. Like put the 650 on, drive it, then put the 750 with the same set up it had on in on and see what it does at the same temperature to be certain. I'll try that. I can be sure due to the crazy weather were having, but I'm in S. Tx and it is warm here half the time, even in winter.

But if you can let me know, do you know if a 750 will out perform a 650 with identical cams, power valves and the same position of secondary linkage?

Thanks

Carb selection depends on tons of variables and one of the biggest IMO is intended use. In my case, a 340 street/strip combo I have tested at the strip with a 650dp and 750dp mighty demon. Both carbs were set up to drive on the street at 13.5 to 14:1. WOT was setup for 12.4 AFR. I run an rpm airgap (dual plane intake). To get the AFR as equel as I could in all 8 cylinders I did a lot of testing reading plugs at light cruise and WOT. The different runner lengths to each cylinder required stagger jetting to get each cylinder as even as I could. I say as even as I could, because the AFR meter just aft of the header collector is an average of one bank and two cylinders are feed by the deep side, and the other two by the shallow side of the intake manifold. I ended up running 4 different size jets in each hole. Long story short the 650 always has a better 60' time over the 750. The 750 always produces a 1 1.5 MPH increase at the 1/4 stripe. For my combo the 650 is best because the ET and consistency is better, (my intended use).
Seat of the pants feel in my case did not work in my car. One day I made a change on the 750 and went for a ride and thought I finally found the magic tune. It felt better than the 650 driving around town. Went to the track and the 60' and 330' times were slower than the 650'. I don't know how much time I've spent changing carb and timing settings trying different setups but it doesn't matter to me. It's a hobby for me to always try and tweek a little more power from my combo.

If I were you I would stick with one carb for testing and get the optimum tune on the engine without your device installed (baseline). Document all jetting, air bleed sizes, pump cams, nozzle sizes, etc.
Install your device and tune the motor again. I say tune again because if you atomize the fuel better then less fuel will be required to make the same power. Document all the settings again.
Go to a dyno and run back to back tests on the same day and you will have better data than now.

 

[70DusterBob]

Carb selection depends on tons of variables and one of the biggest IMO is intended use. In my case, a 340 street/strip combo I have tested at the strip with a 650dp and 750dp mighty demon. Both carbs were set up to drive on the street at 13.5 to 14:1. WOT was setup for 12.4 AFR. I run an rpm airgap (dual plane intake). To get the AFR as equel as I could in all 8 cylinders I did a lot of testing reading plugs at light cruise and WOT. The different runner lengths to each cylinder required stagger jetting to get each cylinder as even as I could. I say as even as I could, because the AFR meter just aft of the header collector is an average of one bank and two cylinders are feed by the deep side, and the other two by the shallow side of the intake manifold. I ended up running 4 different size jets in each hole. Long story short the 650 always has a better 60' time over the 750. The 750 always produces a 1 1.5 MPH increase at the 1/4 stripe. For my combo the 650 is best because the ET and consistency is better, (my intended use).
Seat of the pants feel in my case did not work in my car. One day I made a change on the 750 and went for a ride and thought I finally found the magic tune. It felt better than the 650 driving around town. Went to the track and the 60' and 330' times were slower than the 650'. I don't know how much time I've spent changing carb and timing settings trying different setups but it doesn't matter to me. It's a hobby for me to always try and tweek a little more power from my combo.

If I were you I would stick with one carb for testing and get the optimum tune on the engine without your device installed (baseline). Document all jetting, air bleed sizes, pump cams, nozzle sizes, etc.
Install your device and tune the motor again. I say tune again because if you atomize the fuel better then less fuel will be required to make the same power. Document all the settings again.
Go to a dyno and run back to back tests on the same day and you will have better data than now.

Excellent~~!!!

Thank you. Have you ever thought of getting a job as a Holley Tech on their phone line. J/K! But that sounds great! Thanks again!

 

[mderoy340]

Excellent~~!!!

Thank you. Have you ever thought of getting a job as a Holley Tech on their phone line. J/K! But that sounds great! Thanks again!

You're welcome. I'm still learning and trying new things every trip to the track.

 

[70DusterBob]

You're welcome. I'm still learning and trying new things every trip to the track.

Here is what I mean. The original graph smoothed out the actual power dive and increase so much you couldn't tell this was in it.

That is prob where the secondaries kicked in I'm thinkin'