Experience with BG blower carbs??
 

I have 2 of Barry grant's Demon carbs that are factory tuned for blower set ups. They are 975 cfm. I have been told by distributor that they should be very close right out of the box. They are boost reference types.

Anyone out there have experience with these?

Thanks.

I see you lurking, JDNCA1 and Wette...
 

Give me your take...

Did you provide all your specs?
 

I know JDNCA1 gave the BG people all of his engine specs and they were pretty close right out of the box. I think some jet changes were made on the dyno but that is to be expected. I think JDNCA's carbs were lean. When making your first runs be sure to keep an eye on the plugs and watch for the formation of a fuel ring before laying into it for a long WOT pass. Better safe than sorry. What plugs are you running? I think some NGK R5671A-9 would be just about the right heat range and will give you accurate readings if viewed after a WOT run. Are you getting pumped?

Yes, cautiously so.........

I ordered them from the blower shop. Marv gave them the basics (C.I., head type, etc...). I just got off the phone with him. I didn't realize that the race demons were all custom order. Apparently there is a new type that can be ordered blower calibrated without removable venturies that comes off the shelf (non custom). I thought that was the case with these, but Marv says no...

I plan on taking it slow and really watching the plugs. I don't really know the difference between heat rings and color critiquing.

Those are the plugs I have been running and have a fresh set in.

On my motor I run NGK R5671A-8 and they just leave a gray ring around the base of the porcelins after a WOT pass. On my engine Dean says that ring indicates a slightly rich condition for racing fuel which is good in a marine environment. That is after maybe an hour of running time with minimal idle time. I also did readings at cruising RPM. Do you use a plug magnifier? If so watch out for shiney areas and small beads of aluminum on the procelins. That would indicate pre ignition or detonation. Also make sure the cen electrode isn't "heat blue" after a hard pass. I am sure you already know this but I recite it sometimes to remind myself. Are you running this weekend? JDNCA1 is planning on flying his Stearman up here tomorrow and we hope to put the WETTE VETTE through the paces. It should be fun. Good tuning!!!

Brad;

I run the 775 race demons with the Removable Sleeves, they were dead on out of the box for the TR set-up with the exception of jets. Had to go up 2 sizes all the way around. Two things to watch; first be sure you lock tight the base plate screws in place (wvette and I were lucky and caught mine before a couple got ingested) also periodically check the boosters to be sure they are staying tight (like at every oil change) I've had to tighten mine 1 time in about 60 hrs. You have to buy a special tool from BG to do this.

The tech guys seem to be very good from BG, I thought about changing sleeves to the 975cfm for more power when I started to turn more r's. While they agreed I would likely pick up some on the very top end, they advised against it because idle and mid range would suffer drastically. They basically saved me 600.00 to make the change. Anyway I've been really happy with the Demons...just look at them compared to a holly, put together much better. Good luck:cool:

I run the NGK 5672A-10's and the -9's (Projected nose plugs)

Brad:

Those carbs should be safe out of the box, make sure to hook up the vacuum fitting on the side of the carburetor to the base of your intake manifold (it is the boost ref. port for the PV) If you have any problems call our shop (706) 864-8544 or Marv.


Doug

Brad, many times boost referencing doesn"t work on heavier boats. If your mid range is shot, hook it up as stock but read your vacuum under the carb to see where your power valves will open. Just above high cruise speed works best.
JB

Thanks for the information guys,
 

I ran them on the hose this weekend and set the timing. Spent a while working on getting the linkage just right. It had a 400rpm roll on top of a 1200 rpm idle at first. Worked on idle mixture screws and got a stable, 900 rpm idle. I've never got that before with past setup. These carbs seem very sensitive to the least change in setting.

JDNCA; I noticed that the base screws were not that tight out of the box and tightened them before installation!!

It's been still all summer here for the most part and the day I want to go out and test, we had 25mph wind. Drove quite a ways to a lake that had a protected marina and a protected strip of water along north side of freeway. Pulled it off trailer and had no forward gear! If it isn't one thing it's another. Just had the gears put back to 1.5 with new clutch by my most trusted mechanic. I'm sure it can't be much. Hope to try it NEXT weekend. :rolleyes:

If I can figure out how to shrink down photos, I'll post a pic of the setup.

Thanks again,
Brad

Engine

Boat

Brad;

Red Lock-tite them, don't take a chance on something stupid like that. ;)

We'll do,
 

Good point. I ingested one of those little allen setscrews from a B&M universal blower manifold on my last motor after 2 seasons running, so there's no reason to have something like that happen again.

Brad;

That is a sweet looking motor and install, will that 21 float with all that weight? :rolleyes: You should FLY in that boat. :cool:

Problem is,
 

I've just crossed the age threshold where I care more about making it back to the dock in one piece than how fast I went, if you know what I mean ;)

Brad I know the feeling,
 

Our pontoon is my favorite boat. All relaxation and no frustration. :cool: Your boat and motor look great!! Hope it runs up to your expectations!! It should fly.

I'm pulling the drive tonight and bringing it in first thing in the morning. Hope to be running this comming weekend.

So you got a 'toon too? One of the best buys I ever made:cool:

Is that motor gonna fit in my 24:D :D :D :confused: :confused: :( :)

Only if we break out the sawzall! And guess whose driving!:D :D

Brad, Everyone should have a 'toon' as a back-up.... Everytime my boat is "down", I know the 'toon' is ALWAYS ready to go, no sweat!! The 'go fasts' are 'gonna break, we know it, and I AM NOT going to stay on the beach or at home because something broke. There are only so many boating days/weekends in a season and they cannot be wasted! Power to the 'toons' !!:)

Also, I am still using your exhaust tips, I really appreciated the favor. I hope everything goes well for you.

George

:D :D :D :D :D :D

barry grant
 

if you need any tech talk to mike knowls at barry grant, he is the head blower tech guy there ,on mine i could not get the idle down that far ,so just let it purge and shif t on down cycle,i had the 775 gold claws, the jetting was close out box,played around with the idle feed restrictors alittle,,got close, good luck