Water injection to lower DB

[Brian Blazer]

On gas boats, we inject water into the end of the stinger to quiet the boats down (3db). Why isn't anyone doing this on nitro? Just curious.

Brian

 

[Ron Olson]

I don't know Brian. I've seen people ask why or why not before. I don't know if there would be one place better than another to place the fitting because I wouldn't think that you'd want it where the water would go into the fuel pressure fitting. There could also be a problem of water exiting the head going back into the combustion chamber after running. I dunno, just thinking out loud.

 

[Ron Saxvik]

On gas boats, we inject water into the end of the stinger to quiet the boats down (3db). Why isn't anyone doing this on nitro? Just curious.

Brian

This would also act to lengthen the pipe.....we used water injection

on our pro outboard (full-sized) to get the pipes to come in if they

were too short.

Are you coming to Seville or with the old man to spectate the big

boats ?

 

[Brian Blazer]

On SAW boats, we sometimes water inject the pipe towards the header to make the pipe seem long during startup. Then shut off the water once the speed gets up.

The water injection I am refurring to is located at the end of the stinger.

We will not be in Seville. We are going to the real boat race in Hillsboro.

 

[Ron Saxvik]

On SAW boats, we sometimes water inject the pipe towards the header to make the pipe seem long during startup. Then shut off the water once the speed gets up.

The water injection I am refurring to is located at the end of the stinger.

We will not be in Seville. We are going to the real boat race in Hillsboro.

Same deal for us....we used the water to get the boat on plane and

then slid the pipe while underway to get into and thru the corners.

Was thinking that the injection in the stinger would do the same

thing but guess not. Was also thinking bout putting a water jacket

around the pipe to muffle the resonance of the pipe itself but not

sure if it would cool the gasses to far and affect the pipe performance.

Guess I am going to have to get busy and get some stuff built so I

can test some of my ideas out in the spring. Not sure how much r/c

racing we'll be able to do though.....kinda getting back into the full

sized stuff but am going to try to get the r/c stuff going too. Time

will tell.

Will miss you at Seville....just heard that there are going to be quite

a few boats there so should be fun. Was also going to try to make

Elmira but that be too much travelling for one day.....who knows ?

May still do that trip.

Hoping to see you and the "old guy" next year....maybe we can hook

up and pound a few down at Toledo in the spring.

C.U.Later,

Ron (the good Sax)

 

[Bart Drieghe]

I've done it on a nitro exhaust and as long as you really do it in the very last end , no changes in performances .

Being honest , it was the cooling water of the header that i used .

Angled towards the outside naturally .

B

 

[snowdog-2112]

Is it just me or do the stock K&B 11 and 13CC Outboards use water in the exhaust to muffle the noise? Seems to me that this was thought of long ago by the ones who brought us the infamous "Fuel to noise convertors" (Thanks JD)

 

[Jerry Dunlap]

Is it just me or do the stock K&B 11 and 13CC Outboards use water in the exhaust to muffle the noise? Seems to me that this was thought of long ago by the ones who brought us the infamous "Fuel to noise convertors" (Thanks JD)

Injecting water into the K&B 11/13cc lower units is an option. It does reduce the noise along with slightly reducing top speed. However, water into a tuned exhaust system would seem to be a different thing than water into a lower unit muffler.

JD

 

[gil sonsino]

After have tried this set up on my gas/cat with sucess using a Mike Tyson muffler with water injection throughout the drain oil hole have saw lot of guys using this on nitro with custom or Prather mufflers with no loss of performance.Low the noise Dbs has made people start some good experimentation and the results are also good.

Gill

 

[Chris Wood]

Not trying to be negative.. I saw jerry crowther at the nats.. he tried teeing into the water line and shooting water up at the end of the stinger on a either 90 or 1" motor mono.. he burned up the motor at the nats..

Not sure why it happened other than just took away from the cooling of the motor and he said he didn't see or hear any difference other than he thought is sounding like it was making bubbles. but he said it was still to loud..

chris

 

[Bart Drieghe]

Chris , there might be just more than just T-ing the waterline that caused the burning up .

-Engine doesn't get the normal flow of water through the head

-pipe is closed off too much , pipe gets extreme hot

While i do use the cooling water of my engine ( on my petrol boat) , i only use the cooling water of the header on my nitro boats .

I've done several tests with water through the exhaust and i had the best combination of performance/sound at the very end of the stinger .

I could lower the DB's if i placed the nipple in the exhaust itself but the performance wasn't the same .

I won't deny that my petrol engine had less issues that the nitro engines.

B

 

[AWaddle322]

I think most of us understand how a tuned pipe works but what i do not understand is why you would not have a water reversion problem with water injection. Water reversion is when water runs back into the motor thru the exhaust system. Can anyone explain?

Sincerely,

Allen

 

[Joe Warren]

Not trying to be negative.. I saw jerry crowther at the nats.. he tried teeing into the water line and shooting water up at the end of the stinger on a either 90 or 1" motor mono.. he burned up the motor at the nats..

Not sure why it happened other than just took away from the cooling of the motor and he said he didn't see or hear any difference other than he thought is sounding like it was making bubbles. but he said it was still to loud..

chris

Chris I seen the same on Jerry 60 mono. he was guessing that the water pressure @ one point exceeded the pipe pressure & let the engine have plenty of water thru the pipe KILLING the brgs...

 

[Wally Marsh]

I think most of us understand how a tuned pipe works but what i do not understand is why you would not have a water reversion problem with water injection. Water reversion is when water runs back into the motor thru the exhaust system. Can anyone explain?

Sincerely,

Allen

I'm with Allen on this one, I've wondered about this for a long time. Why wouldn't the "supercharging" effect of a properly tuned pipe not put water back into the the motor? Inquisitive minds looking for answers.

the Wallster

 

[Don Ferrette]

Not trying to be negative.. I saw jerry crowther at the nats.. he tried teeing into the water line and shooting water up at the end of the stinger on a either 90 or 1" motor mono.. he burned up the motor at the nats..

Not sure why it happened other than just took away from the cooling of the motor and he said he didn't see or hear any difference other than he thought is sounding like it was making bubbles. but he said it was still to loud..

chris

Chris I seen the same on Jerry 60 mono. he was guessing that the water pressure @ one point exceeded the pipe pressure & let the engine have plenty of water thru the pipe KILLING the brgs...

Hmmmmm. It would seem that enough water to wash out a set of bearings would have put the flame out & stopped the motor from running. I'm thinkin' if he T'd off the cooling line the motor got cooked from running too hot but was rich enough to keep running. I did this once, had a water line split but had enough water that it kept running. It was fast too, never realized I had a problem that is until it quit on the cool down lap at the end of the heat. When I checked why it stopped & sounded really wierd trying to unsuccessfully fire it up, I found it burned a hole clean thru the piston. Besides, Chris said Jerry was shooting water AT the stinger end, not into it, I don't believe there is enough pulse reversion that far downstream to draw water in all the way back to the motor. I've seen the gas guys have success with sending water in the back of an add on muffler flowing in the same direction as the exhaust gases. Also they either use a seperate water line or use the DISCARGE side of the water jacket & do not take away any water meant for cooling the motor.

 

[AWaddle322]

Not trying to be negative.. I saw jerry crowther at the nats.. he tried teeing into the water line and shooting water up at the end of the stinger on a either 90 or 1" motor mono.. he burned up the motor at the nats..

Not sure why it happened other than just took away from the cooling of the motor and he said he didn't see or hear any difference other than he thought is sounding like it was making bubbles. but he said it was still to loud..

chris

Chris I seen the same on Jerry 60 mono. he was guessing that the water pressure @ one point exceeded the pipe pressure & let the engine have plenty of water thru the pipe KILLING the brgs...

Hmmmmm. It would seem that enough water to wash out a set of bearings would have put the flame out & stopped the motor from running. I'm thinkin' if he T'd off the cooling line the motor got cooked from running too hot but was rich enough to keep running. I did this once, had a water line split but had enough water that it kept running. It was fast too, never realized I had a problem that is until it quit on the cool down lap at the end of the heat. When I checked why it stopped & sounded really wierd trying to unsuccessfully fire it up, I found it burned a hole clean thru the piston. Besides, Chris said Jerry was shooting water AT the stinger end, not into it, I don't believe there is enough pulse reversion that far downstream to draw water in all the way back to the motor. I've seen the gas guys have success with sending water in the back of an add on muffler flowing in the same direction as the exhaust gases. Also they either use a seperate water line or use the DISCARGE side of the water jacket & do not take away any water meant for cooling the motor.

The way I rember it Jerry's boat it was the bearings had welded itself to the crankshaft. No hole in piston.

Allen

 

[Don Ferrette]

Not trying to be negative.. I saw jerry crowther at the nats.. he tried teeing into the water line and shooting water up at the end of the stinger on a either 90 or 1" motor mono.. he burned up the motor at the nats..

Not sure why it happened other than just took away from the cooling of the motor and he said he didn't see or hear any difference other than he thought is sounding like it was making bubbles. but he said it was still to loud..

chris

Chris I seen the same on Jerry 60 mono. he was guessing that the water pressure @ one point exceeded the pipe pressure & let the engine have plenty of water thru the pipe KILLING the brgs...

Hmmmmm. It would seem that enough water to wash out a set of bearings would have put the flame out & stopped the motor from running. I'm thinkin' if he T'd off the cooling line the motor got cooked from running too hot but was rich enough to keep running. I did this once, had a water line split but had enough water that it kept running. It was fast too, never realized I had a problem that is until it quit on the cool down lap at the end of the heat. When I checked why it stopped & sounded really wierd trying to unsuccessfully fire it up, I found it burned a hole clean thru the piston. Besides, Chris said Jerry was shooting water AT the stinger end, not into it, I don't believe there is enough pulse reversion that far downstream to draw water in all the way back to the motor. I've seen the gas guys have success with sending water in the back of an add on muffler flowing in the same direction as the exhaust gases. Also they either use a seperate water line or use the DISCARGE side of the water jacket & do not take away any water meant for cooling the motor.

The way I rember it Jerry's boat it was the bearings had welded itself to the crankshaft. No hole in piston.

Allen

Once again you've missed the point. The hole in the piston was only an example of how HOT the motor could get & keep running..........

 

[lohring]

Nearly every gas boat in our club runs a water injected stinger muffler using water from the engines cooling water outlet. If you couple this with an inverted stinger, the results are really impressive. There are no problems with water getting into the engine, power loss, or changing tuned pipe pperformance. We have also done dyno and on the water testing of water injection into the header. This "lengthens" the pipe and broadens the power band considerably. We use a tee off the engine's cooling water inlet. Here, you do need to be careful not to get water into the engine when the boat is moving but the engine is shut off. This won't be a problem if the water is shut off before the engine.

Lohring Miller

 

[AWaddle322]

Nearly every gas boat in our club runs a water injected stinger muffler using water from the engines cooling water outlet. If you couple this with an inverted stinger, the results are really impressive. There are no problems with water getting into the engine, power loss, or changing tuned pipe pperformance. We have also done dyno and on the water testing of water injection into the header. This "lengthens" the pipe and broadens the power band considerably. We use a tee off the engine's cooling water inlet. Here, you do need to be careful not to get water into the engine when the boat is moving but the engine is shut off. This won't be a problem if the water is shut off before the engine.

Lohring Miller

And how do acomplish cutting off the water prior to killing the engine?

Allen

 

[Bob Finn]

The ones I've seen used a servo operated valve. From what I've seen, thats not neccesary if you put the water into an add-on muffler angled towards the outlet. Seems to work fine, and it really does quiet one down.