Pro charger and carb Info
 

Going to run a pro charger with a carb box.Not a blow thru hat.Do the guys that are running this set up use, besides a boost gauge are you running a AFR gauge.Little confused on this matter could someone clear this up.Is there any off the shelf carb set up for use in a pro charger box.Any help would be appreciated. Thanks JOHN SR

No clue on the carb, but I would want the wideband 02.

I think a buddy of mine, has a like new prosystems blow thru, and possibly a carb box setup he was selling. You want me to find out about it?

Any modified engine should have an AFR gauge in my mind. I run blow thru on my Ford so the only comment I'll make is an extreme velocity hat system flows better.

I ran one several years ago, did use a Holley off shelf, then ordered threw Holley the marine kit (J-tubes, etc.). I didn't use a AFR, just read the spark plugs for a rich setting. Never had any trouble, maybe I was lucky?

If you are running the carb in a box and the floats are under pressure the carb has to be tweeked, If you are running a hat and the floats are seeing atmosphere not MUCH changes internally. make sure you error on the rich side until you get your AFR readings throughout the RPM range

The reason for wanting to run the box, is from all that I have read is it is a easier set up to tune, using a flame arrestor, helps smooth the air flow out more, so again seems as it will be more tune friendly. Also I do believe that the carb needs less internal changes vs the hat style carb. Only shooting for 550-600 hp, so the box should do the trick for us.

MILD what does your buddy have as far as CFM wise ? Would only be looking for a carb, as we have the box..

Thanks guys, any more info is always great..

John jr :drink:

John he has a pro systems 750. It's like brand new. It can be run in a box or with a hat.

it is easier to make your jet and other carb changes with a hat,it,s a pain in the azz removing the carb from the box.

Yes, a carb in a box requires less mods. No shaft seals. Probably all air emulsion circuits being left stock.The power valve boost vs. no boost transition may not be an issue stock. (biggest drawback to blow thru) Wouldn't necessarily say it's easier to tune though. The box cover needs to be removed every time you want to play. Jetting and cams can be a pain possibly requiring the carb to come out. Get a carb you can adjust air idle bleeds and has good floats. Obviously, boost sensing fuel pressure regulator is still necessary.

The box WILL have more turbulence though. What is the engine?

Only problem i see with the hat, is on high boost setups, you really need to mount the hat straight on. Meaning the inlet should face the front of the boat. My buddys setup would make one bank run a bunch leaner than the other bank. Probably not an issue with lower boost, and a spacer between the hat and carb can help that out a bit. I think the hat is the way to go.

Not saying it can't be done but if it was my hard earned money on a forced air motor I would want to get the tune as close as I could on a dyno and then re-tune in the boat using afr and plug readings. Afr's are great but they don't tell you what each individual cylinder is doing. I would also want a hat as opposed to a box not just for tunning but if you had an issue down the road like stuck float or something it would make life alot easier.

The hat is not "legal" on a boat..only the box with a carb, I ran this setup for 2 seasons, had Patrick @ prosystems build me a carb, was spot on out of the box, the box is a royal pain in the a$$ to deal with as you need to remove the top to make any adjustments, also need to remove carb to remove bowls, the issue that I kept having was carb flooding when coming off plane, had to cycle the fuel pump(elec) off for a few seconds to get by with the issue...switched to our own EFI and never looked back...performance is ok with the box though...good luck

what unit do you run and how much boost?

This is something else that I was going to put in my other post aswell. Also running a flame arrestor is '' said '' to smooth out the turbulence, Find out what kinda coin your buddy is looking to get ??


EZ. This is also correct, the hat isn't certified by the coast guard.

Said engine is a forged 355 sbc. Going to run about 10-15 lbs through it. Just trying to get a good idea.


As always thanks for the info. I am running a procharger on my vehicle, but it is EFI, not carbed, so would like to get as much info on a carbed set up as we can. Been doing a bit of reading about it aswell. Thanks

John jr

I run the Vortech blow-through systems with boxes , i used Quick fuel Q-750-ban carbs did not have any problems with the tune up . The AFR gauge would be nice for a reference, but it is tough to watch to be able tune off of , dyno pulls are much more user friendly ,I just added boost pressure and fuel pressure gauges to the boat . The only problem I had was the return line off the fuel regulator was too small and made my fuel go all over the place other than that I am real happy

I just pulled a pro charger blow thru 555ci engine off the dyno , used a CSU blow thru carb , they are the blow thru guys , took a lot of tuning !! , 23 pulls , jetting went from 76 to 92 in the rears , 10 air bleed changes , fuel system mods , went from 650 hp with a blow thru efi merc system , To the carb blow thru making 821 hp- 867 tq @5000, 4-5 psi of boost , 93 pump, a/f 11.9 , bsfc# 48.idle at 900. also we went away from the box system becouse of the problem jetting and if it floods over , you have a bomb . should be up on the website soon www.thunder-boats.com Bobby

Great info! what were the primary jets? and PVs front and rear?

I run a M3 only 5-6psi as of now, I talked to Patrick @ Prosystems, he did not want me to run without a box, as he felt there was not way to keep from blowing a small amount to fumes out thru the throttle shafts and in a enclosed engine compartment...not good...

ezstriper! So what configuration carb are you running.Is it set up for a box a blow thru or a stock type. JOHN SR

Weird. My buddy had prosystems blow thru's, with the throttle shafts pressurized via fittings for that purpose.

Do you have any pics of pressurized throttle shafts .I'm just trying to picture in my little brain,what you are describing

Let me see if I can find one

I was told by both manufactures that the only coast guard approved method of a blow-through carb application was with a box and if you had a fire your insurance co would not cover .

john, just remember you dont need alot of carb or cfm for a blow-through set up..all you may need is a 650 cfm carb..the air is forcing the fuel out of the carb..to be honest call c&s and have them build you a arosol carb with progressive linkage..i always use a carb that all four barrels open at once so your getting a equal fuel charge through the transition..their is a few tricks that need to be done to the carb in a blow through system..just changing jets dont cut it..you also have to open op the passeges to tje power valves to feed the bigger jets..just have c7s build a carb..http://www.candsspecialties.com/abcmods.html

I now am running our own EFI with a hat, using megasquirt, our own harness and tune...

He said even with "sealed" throttle shafts they do blow out a small amount of fuel under boost...said they noticed it on the dyno...

with carb...
http://i227.photobucket.com/albums/d...r/100_1741.jpg

with EFI

http://i227.photobucket.com/albums/d...pse6b4071c.jpg

does your megasquirt throttle body have a shaft for the throttle blade or blades because if so you still may have some fuel leakage under boost.the deal patric from pro systems sells for carb apps with a hat consists if modifying the carb and a plate under the carb.it is a really neat deal.

no fuel thru the throttle body, port EFI, according to patrick they do not seal totally, I ask as I did not want to run the box...knew was a pain...he insisted when he did the carb for me..., megasquirt is only the ECM, using a 1000cfm billet throttle body

ok,now i understand your setup.