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Crossover exhaust
- Thread starter jim
- Start date
Daddy Dave
Well-known member
Heard that boat run on the trailer at Melborne during the January FAA meeting. The crossover was connected to MagnaFlow mufflers mounted to transom butt plates. The boat was very quiet on the trailer.
A few racers and High Performance exhaust system builders are bragging about "X" joints sucking exhaust gasses out of valve chambers. Sounds like voodoo to me. Claiming + 20 hp.
The boat in question did not have an "X" or "H" it had crosses.
A few racers and High Performance exhaust system builders are bragging about "X" joints sucking exhaust gasses out of valve chambers. Sounds like voodoo to me. Claiming + 20 hp.
The boat in question did not have an "X" or "H" it had crosses.
"X" and "H" crossovers do work and have been used for years in Nascar and elsewhere. A lot has been written about it. Here is one small example of a test scenario:
http://www.pontiacstreetperformance.com/psp/exhaust2.html
Jim
http://www.pontiacstreetperformance.com/psp/exhaust2.html
Jim
A
Anonymous
Guest
Can't tell from your pics, do the two banks connect to reach other?
I have a crossover pipe on my truck. It makes the exhaust tone really mellow and takes out the "rapping", as well as boosting power at almost every RPM. Helps scavenging and cancels out some sound waves.
High time airboats started using some good exhaust tech to boost torque and eliminate some sound.
I have a crossover pipe on my truck. It makes the exhaust tone really mellow and takes out the "rapping", as well as boosting power at almost every RPM. Helps scavenging and cancels out some sound waves.
High time airboats started using some good exhaust tech to boost torque and eliminate some sound.
hillrunnerfl
Well-known member
I know all the guys involved in this boat. My wife's cousin built the hull and one of guys at Stumpjumper rigged it. The pipes cross sides of the boat thru the resonators. and exit to the mufflers. There is real no cross over connection between the cylinder banks. I used to run crossover pipes on small block chevy motors, and they will help if installed correctly.
The only way to verify any power increase is on a dyno, and I don't think it's been tested. I looked at the boat, and must say it looks good, and performs very well. Quiet, maybe.
Still no way to get rid of prop noise on a boat like this. It takes power to push a boat like this. And power makes noise. (I have see a "LOT" of these 383 crate motors on boats like this and most of them last a year maybe two before shucking rods
By far the quietest boat I know is my buddies 13 foot deckover with a 125 on it. It takes so little power to push it, it doesn't make much noise.
The only way to verify any power increase is on a dyno, and I don't think it's been tested. I looked at the boat, and must say it looks good, and performs very well. Quiet, maybe.
Still no way to get rid of prop noise on a boat like this. It takes power to push a boat like this. And power makes noise. (I have see a "LOT" of these 383 crate motors on boats like this and most of them last a year maybe two before shucking rods
By far the quietest boat I know is my buddies 13 foot deckover with a 125 on it. It takes so little power to push it, it doesn't make much noise.
airboat383
Member
Really the prop noise on that boat isn't bad either. He's got the wide blade Power Shift Sirrus 2 blade. He's got it set so it only turns 4900 rpm wide open. Thats right where the 383 GM crate engine makes it's torque. So far it is the quietist auto boat i've at idle and wide open
A
Anonymous
Guest
hillrunnerfl":3rekhe0d said:
I've seen numerous dyno tests proving the power benefits of crossover exhaust. It flat works, and sounds great to boot.
BTW, Hillrunner, check your private messages/
Red
G
Guest
Guest
cntry has the cross over system on his boat and it is quite
basketcase0302
Well-known member
Jim,
This was the boat in the "CSI Miami" episode if I'm not mistaken. I saw this boat at the River Ranch jamboree this past year. Very quiet, (just like Cntry's). Only thing i could hear when he crossed the field was the prop!
Basketcase
This was the boat in the "CSI Miami" episode if I'm not mistaken. I saw this boat at the River Ranch jamboree this past year. Very quiet, (just like Cntry's). Only thing i could hear when he crossed the field was the prop!
Basketcase