Freestyle Annular Discharge
- Thread starter munki63
- Start date
GIL
Power In The Hands Of Few
- Location
- Cullman AL
munki63, keep this simple. Look down the throat of a Novi or Full Spec and tell me what you see. Now look down the throat of a BlackJack and tell me what you see.
Which one do you think is going to flow more and which one do you think is going to be more crisp and responsive?
Once you take all the smoking mirrors out of the equation, it's pretty obvious.
Which one do you think is going to flow more and which one do you think is going to be more crisp and responsive?
Once you take all the smoking mirrors out of the equation, it's pretty obvious.
- Location
- Lake Havasu City, AZ USA
^^^
A bombsight/spray bar blocks basically 9% of the throat of a carb.
:brap:JaCk!
A bombsight/spray bar blocks basically 9% of the throat of a carb.
:brap:JaCk!
Then how much does a throttle plate turned edgeways block ? You will never get 100% on any carb , even at full throttle .
Why are watercraft carbs known only by a name and throttle plate size? Never any mention of venturi area.
- Location
- Rochester, NY
Yes, but that bombsight puts the fuel in the highest velocity section of flow...whereas annular discharge is put very close to the outer wall where, for laminar flow, the velocity is ZERO. It's a pressure vs. flow design consideration, and there's benefits to each in different scenarios.
I can tell you that modded 38's with a brass tube simply didn't work for me and my style of riding. I got much more instant response with stock 38's and a lightened flywheel (and with unfilled crossover). This was tried back to back on two different skis (a ported 735 and a ported 701) with at least 4 timing curves each, and the outcome was the same. Carbs were all tuned with snail synchro and pet-2100 tach. So, add me to the list of not believing the "hype".
I haven't drawn up the carbs and flow modeled them yet, but man I want to...I think the brass tube hurts more than the stock bombsight, since the fuel port is blocked from the direct high velocity airflow (i.e, it's hidden under the "hood").
Last edited:
Modding with a brass tube?
So your saying the bomb site drops the fuel into the highest turbulence part of the carb for maximum mixture... So the other type just kinda bleeds out the walls of the carbs? Or do I have it wrong?
- Location
- Ahwahnee, CA
Here's a decent pic. About half way down the post http://www.greenhulk.net/forums/showthread.php?t=101642 I couldn't find a video
- Location
- Ottawa, IL
"Give me Black jacks or give death. "
- Location
- Largo, Fl
No but Gil has a 12 minute video of his ski idling on a trailer.
- Location
- South Africa
A 'sort of' alternative method of annular discharge
I modded(hacked) some sxr 40mm carbs lately. Flow area at throttle-plate equals 36,3mm(Throttle bar is 5,5mm wide). Have moved house so didn't have my lathe available to do a pro job, ground out venturi and bombsight by hand to 40mm and installed 4mm brass tube across the bore(flow area = 37,4mm). Six holes set at equal distances in the bore at about 10-degrees below horizontal. Works very well. Learnt this mod from RC cars. I was definitely worth it.
I modded(hacked) some sxr 40mm carbs lately. Flow area at throttle-plate equals 36,3mm(Throttle bar is 5,5mm wide). Have moved house so didn't have my lathe available to do a pro job, ground out venturi and bombsight by hand to 40mm and installed 4mm brass tube across the bore(flow area = 37,4mm). Six holes set at equal distances in the bore at about 10-degrees below horizontal. Works very well. Learnt this mod from RC cars. I was definitely worth it.
Attachments
Last edited: