Blow Thru Centrifical Guru's

[LittleDcsRodShop]

I'm sure there are a few Blow thru guys around & about so I am curious as to whether or not all of you are running carb enclosures ??? Is anybody running a bonnet or "carb hat" ?? I remember the insanly fast 18' small block powered Donzi that ran like 120+ that was owned by GEO on oso ran a bonnet, however if I remember corretly it was EFI (which yes I would like to be doing but out of the budget)..

I know that all the "marine" kits come with enclosures (procharger/vortech) as well as the R-Tech setup (which I would also love to have btw)

So I guess what I'm asking is anybody out there running a Blow Thru Centrifical with a Cabureter & running a "carb hat" instead of the eclosure ??

Without trying to be a smart azz in any way I'm really not not looking for "don't you think the mfg's know what they are doing & use carb enclosures for a reason answers"

 

[Airpacker]

the idea behind the "box" is that the carburetor isn't really under pressure. Seals and gaskets between parts of the carb were never designed to contain any more than a few pounds of fuel pressure. In theory, inside the box is all the same pressure so there is no pressure differential from inside the carb to outside the carb.

 

[LittleDcsRodShop]

Thanks for your response..

I do understand what you are saying about the pressure & I could be totally wrong but I could't see that being a problem running 6-8lbs of boost on a properly setup blow thru carb..?.. There are allot of non marine setups blowing a Ton of boost through carbs with hats on them & no box..However that being said I'm all ears & always willing to listen to opinions (well most of the time.. haha.)

So here here is my "personal" main problem with the box :: When it comes time for maintnance, tunning, ect..ect.. on the carb its obvlously going to make it much more difficult esp. if i happen to be sitting at the dock.. Another is the fact that the box is not going to seal up perfect therefore having a slight & (very minimual i'm sure) pressure drop.. Yes I can be sealed up better but there goes more to the list above.. Lastley I could be wrong again but it seems to me that the motor would be a bit more responsive with a carb hat over the box ??

How about the saftey issues of a hat over the box ?? I assumed the box deal had something to do with Coast guard approval ect.. ?? Was that a wrong assumption ??

 

[HaxbySpeed]

I've got a customer with a pair of Carb shop blow through with SME bonnets. Three seasons @10lbs boost with no problems so far. I haven't done any enclosed vs bonnet comparisons, but this one seems to work well.

 

[FULL FORCE]

Thanks for your response..

I do understand what you are saying about the pressure & I could be totally wrong but I could't see that being a problem running 6-8lbs of boost on a properly setup blow thru carb..?.. There are allot of non marine setups blowing a Ton of boost through carbs with hats on them & no box..However that being said I'm all ears & always willing to listen to opinions (well most of the time.. haha.)

So here here is my "personal" main problem with the box :: When it comes time for maintnance, tunning, ect..ect.. on the carb its obvlously going to make it much more difficult esp. if i happen to be sitting at the dock.. Another is the fact that the box is not going to seal up perfect therefore having a slight & (very minimual i'm sure) pressure drop.. Yes I can be sealed up better but there goes more to the list above.. Lastley I could be wrong again but it seems to me that the motor would be a bit more responsive with a carb hat over the box ??

How about the saftey issues of a hat over the box ?? I assumed the box deal had something to do with Coast guard approval ect.. ?? Was that a wrong assumption ??

My buddy uses the bonnets on his 7lbs of boost, it can leak past the carb seals at the throttle shaft under boost, but he sent carbs in to be worked and solved that issue, much easier to tune and in my opinion looks alot better

 

[LittleDcsRodShop]

Thanks.. I agree they do look better & another one of my reasons that may sound silly to some.. Yeah I know the BG carbs advertise sealed throttle shafts.. I definatly agree with the maintnance part as well..

Are those M1's ? on HP 500's ?? Looks like they are spinning pretty hard..? Out of curiosity who is doing his carb work ?? I am sending a few of my brackets out to powder coat in the next day orso so I am trying to get a game plan on my intercooler routing ect.. I am also waiting to get a crankshaft accesory pully from Vortech.. I would like to mount my inercooler a bit differantly in order to clean it up a bit & get the look I want..

 

[FULL FORCE]

Thanks.. I agree they do look better & another one of my reasons that may sound silly to some.. Yeah I know the BG carbs advertise sealed throttle shafts.. I definatly agree with the maintnance part as well..

Are those M1's ? on HP 500's ?? Looks like they are spinning pretty hard..? Out of curiosity who is doing his carb work ?? I am sending a few of my brackets out to powder coat in the next day orso so I am trying to get a game plan on my intercooler routing ect.. I am also waiting to get a crankshaft accesory pully from Vortech.. I would like to mount my inercooler a bit differantly in order to clean it up a bit & get the look I want..

I believe they are M1's, were hp500's now 509CI with Edelbrock heads and 525 cams, boat is Lake Effect, he is also on the site you can aski him who did the carb work, I forgot, send him a messege..

 

[LittleDcsRodShop]

I believe they are M1's, were hp500's now 509CI with Edelbrock heads and 525 cams, boat is Lake Effect, he is also on the site you can aski him who did the carb work, I forgot, send him a messege..

Thanks.. Btw: Be sure to keep those Saber buddys of yours in line !!

 

[FULL FORCE]

Thanks.. Btw: Be sure to keep those Saber buddys of yours in line !!

HA!! very hard to do!!!! you have Jim's old one right?

 

[LittleDcsRodShop]

Yeah.. Trying to do the old girl up right in an attempt to somewhat keep her "legend" statis.. haha

 

[FULL FORCE]

Yeah.. Trying to do the old girl up right in an attempt to somewhat keep her "legend" statis.. haha

Sweet! maybe someday Jer will sell me Clifford!!

 

[LAKE EFFECT]

Thanks.. I agree they do look better & another one of my reasons that may sound silly to some.. Yeah I know the BG carbs advertise sealed throttle shafts.. I definatly agree with the maintnance part as well..

Are those M1's ? on HP 500's ?? Looks like they are spinning pretty hard..? Out of curiosity who is doing his carb work ?? I am sending a few of my brackets out to powder coat in the next day orso so I am trying to get a game plan on my intercooler routing ect.. I am also waiting to get a crankshaft accesory pully from Vortech.. I would like to mount my inercooler a bit differantly in order to clean it up a bit & get the look I want..

Performance Carbs out of Ontario California is where I got the carbs. Engine setup is a little different now, as Tim mentioned. Still M1 Prochargers, those are 3.05" pulleys, running 2.85" pulleys now, blowers are maxed out at around 7-8 psi.

Your not going to have an issue sealing the carbs bowls. The throttle shafts will seep a little. My plates are referenced to the bonnet, which keeps boost on the shafts, and keeps the seeps to a minimum. I'm also running blow off valves. Throttling in rough water is when you might get some seeping.

Its very important you have a good fuel system. Im running a Aeromotive pump, thru #10 lines feeding the motors and #8 returns. You also need a fuel pressure regulator that increases pressure 1 for 1 with boost.

I also returned your email. Give me a call when you get a chance.

LE

 

[LittleDcsRodShop]

Performance Carbs out of Ontario California is where I got the carbs. Engine setup is a little different now, as Tim mentioned. Still M1 Prochargers, those are 3.05" pulleys, running 2.85" pulleys now, blowers are maxed out at around 7-8 psi.

Your not going to have an issue sealing the carbs bowls. The throttle shafts will seep a little. My plates are referenced to the bonnet, which keeps boost on the shafts, and keeps the seeps to a minimum. I'm also running blow off valves. Throttling in rough water is when you might get some seeping.

Its very important you have a good fuel system. Im running a Aeromotive pump, thru #10 lines feeding the motors and #8 returns. You also need a fuel pressure regulator that increases pressure 1 for 1 with boost.

I also returned your email. Give me a call when you get a chance.

LE

Thanks for the email.. Hadn't got a chance to read through it but Im about to..

Yeah I definatly plan on running a good dedicated fuel system.. Most likely an Aeromotive A1000 & definatly will be doing the 1:1 rise with boost on the regulator..

 

[unnatural]

Earhart just dyno'd a 572 inch @ 1200hp. Had an f2 Procharger with a 960 c&s blow thru carb with a bonnet. Ran about 15psi of boost and had a 1:1 boost referanced fuel pressure regulator. Granted it was a drag race motor and i'm not a carb guy, but it worked flawlessly. Didn't see any throttle shaft leaks even at high boost levels. I'm not sure if c&s does any marine work but they may be an option.

 

[LittleDcsRodShop]

Earhart just dyno'd a 572 inch @ 1200hp. Had an f2 Procharger with a 960 c&s blow thru carb with a bonnet. Ran about 15psi of boost and had a 1:1 boost referanced fuel pressure regulator. Granted it was a drag race motor and i'm not a carb guy, but it worked flawlessly. Didn't see any throttle shaft leaks even at high boost levels. I'm not sure if c&s does any marine work but they may be an option.

I have talked with C&S and from what I can tell they do have there stuff togather on blow thru technology & if money wasn't an object I would definalty look into them alittle further..

 

[unnatural]

Yeah, I know what you mean. This guy paid over $1400 for his.

 

[LittleDcsRodShop]

I just looked back & they were in the 1150.00 range for one of their billet aerosols.. The differance in my quote may be that I would definatly not be needing that much carb & he may have even used a 4500 instead of a 4150 like would better fit my application.. Feel free to post any pics you may have of the setup on the drag motor.. Marine or not its all cool stuff & welcome here !!

 

[LittleDcsRodShop]

Anybody used any of the Barry Grant bt carbs ? Seems like allot of carb for the coin ?

Just curious of any real world experiance ?

 

[Trim'd Up]

Anybody used any of the Barry Grant bt carbs ? Seems like allot of carb for the coin ?

Just curious of any real world experiance ?

I had them on my last boat. N/A though, so not the same but I never could get them quite right. They sure looked pretty but the holley's ran better. I am no carb guru by any means though.

 

[LittleDcsRodShop]

Anybody want to comment on the effect of tubbing length from the charger to the intercooler and then up to the carb & its relation to boost & even throttle response loss ??

I ask this b/c I have some ideas of relocating my intercooler a bit & I see allot of centrificals making Huge power in street & drag cars ect.. with a few miles of tubbing work & routing..

I will go ahead & add that yes I know I am not dealing with a drag car.. & yes I realize that most of these guys are launching at rediculous rpm's & have boost built up & ready..

Common sense tells me to keep all tubbing as short & straight shot as possible but anybody want to comment on this..?