40 Pipe Stinger Size?

[jaxracer]

Hey guys, looking for input on what is a recommended stinger size for a 40 outboard pipe? I’ve heard a few different opinions so wanted to see what the general consensus was. Running a .430 bore carb if that makes a difference. 

Thanks!

 

[Carl Van Houten]

Hey,

I see that you are getting absolutely no help with your question from the good ole IW crowd... The stinger acts like a variable pressure  resistor. The length and diameter are determined by many variables. If you are running a Nova Rossi 46 power head your best bet would be to order a SPP 46 muffled carbon pipe from Ron Shaw and forget about trying to figure out anything about your pipe. That pipe is the BOMB my friend. You see that I have one on my Mod 40 and Talley has the same one on his. The biggest problem you will have with the carbon pipe will be trying not to run over the back marker boats LOL.

-Carl

 

[BradSpencer]

Great topic. I had a 46 outboard pipe made with a 9mm(.350”) ID stinger, with plans to test and slowly drill it out in small increments.

My train of thought was the smaller stinger used with a smaller carb(10mm/.394”) should help generate engine temp, and assist with the inherent problem of fuel draw in outboards where the fuel tank is mounted considerably lower than the carb...... 

Also thinking it will help with on/off throttle situations. Outboards generally don’t see as much WOT as a hydro for example. Yet the pipe specs(stinger ID, length, volume etc) are the same for a Hydro pipe and a outboard pipe .....

 

[aaron alberico]

A lot comes into play regarding stinger size, carb bore, spraybar size, rpm range, nitro% etc, but a good all round size is 9.5mm -10mm.. 

As Carl stated get yourself SPP 45o/b best  out there.. just my opinion..

regards Aaron 

 

[topfuel443]

Ill be the third one to say it. Get the SPP quiet pipe from Ron. We tested the Irwin, Hopper, Aerotech and a homemade pipe on the NR, nothing came even close to the SPP. 

 

[aaron alberico]

Now the SPP pipe was designed for Novarossi 46 by Ian Inverarity ...

 

[jaxracer]

Good info Brad and Aaron. Appreciate it guys. 

Are the Salisbury pipes available again, I was under the impression they were on backorder?

And currently running the Irwin stamped pipe. It’s a good bit faster on the NR than the Equi we tried. We have another stamped pipe as well but it has a different stinger size is the reason for the question.

Also, side question, if these Salisbury pipes run as well as advertised, has anyone tried one on a Nelson and what were the results?

 

[HTV Boats]

Back to your info, I won't say a .430 carb will not work but to me it's like putting a 1000cfm carb on a 283 Chevy. I think .375-.390 will run and needle much better. As to stinger outlet,  .340 -,330. The Nelson aircraft .40 set a world record with a much smaller stinger. Maybe .250? 

Mic

 

[topfuel443]

Are the Salisbury pipes available again, I was under the impression they were on backorder?

Ron shows 2 in stock on his site. 

 

[dave roach]

Had a member in the boat club that had a 45 Rossi outboard with a big carb on it and was chasing the needle all the time and I said one day the carb to big and he said that wasn't the problem.I took a K/B red carb and put a sleeve on it to fit the Rossi 45 and told him to try the carb.when he put the carb on it was a total animal.It run better and had a needle adjustment know and he was every happy with the out come.The Irwin pipe he was running had a .320 stinger out let on it.I think the stinger out let dia.is for your set up.

Dave

 

[Jim Allen]

Back to your info, I won't say a .430 carb will not work but to me it's like putting a 1000cfm carb on a 283 Chevy. I think .375-.390 will run and needle much better. As to stinger outlet,  .340 -,330. The Nelson aircraft .40 set a world record with a much smaller stinger. Maybe .250? 

Mic

Hi Mic,

How are you & Jay doing? Do you remember the HTB-360 I ran in Charleston with Jay as my back up man. I used a Nelson .45 long stroke engine with a OS-Max 9B (.4724" bore) carburetor. The carburetor needed a special adaptor & venturi to work properly. It works very well with the high & low speed needles once they were properly set. I use a Silver bullet tuned pipe with a .3438" ID X 4.750" long stinger. The Nelson .40 short stroke engine used a magic muffler with a .250" ID stinger. The Nelson .45 long stroke engine with a magic muffler has a .272" ID stinger & this is the same engine used on the HTB-360.

JA

 

[Carl Van Houten]

Good info Brad and Aaron. Appreciate it guys. 

Are the Salisbury pipes available again, I was under the impression they were on backorder?

And currently running the Irwin stamped pipe. It’s a good bit faster on the NR than the Equi we tried. We have another stamped pipe as well but it has a different stinger size is the reason for the question.

Also, side question, if these Salisbury pipes run as well as advertised, has anyone tried one on a Nelson and what were the results?

Who has the fastest 40 modified you have ever seen? I'll bet it had an SPP on it. I would just order one and get that problem behind you.

 

[jaxracer]

Hi Mic,

How are you & your dad doing? Do you remember the HTB-360 I ran in Charleston with you as my back up man. I used a Nelson .45 long stroke engine with a OS-Max 9B (.4724") carburetor. The carburetor needed a special adaptor & venturi to work properly. It worked very well with the high & low speed needles once they were properly set. I used a Silver bullet tuned pipe with a .3438" ID X 4.750" long stinger. The Nelson .40 short stroke engine used a magic muffler with a .250" ID stinger. The Nelson .45 long stroke engine with a magic muffler has a .272" ID stinger & this is the same engine used on the HTB-360.

JA

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You guys were spot on. The Salisbury .46 pipe screams with the right prop.

Still experimenting with my Irwin stamped pipe though as it still runs good. With that being said, how do you guys recommend stingering down a pipe? I see a lot of people with brass tubing. What’s the best method?

Thanks!!

 

[Jim Allen]

Hi Mitch,

If you can find a  thin walled brass tubing that will telescope inside the ID of of your existing tuned pipes stinger, this would be the easiest method to decrease the ID & increase the total length. Since thin walled rigid brass tubing has a .015" thick wall, very small reductions in the ID of the stinger can be made.  Both things will increase the HP produced & both things will increase the engines operating temperature but not in the same way. Small decreases in the stingers ID will greatly increase the engines operating temperature. This is why you want to make small decreases to the stinger's ID. Large increases in the stinger's length have a less of an effect on raising the engines operating temperature. The telescoping tubings can be held in place with a .026" diameter steel wire by cross drilling both pieces. 

One more important thing when using the Nelson .45 long stroke engine. This is the same engine as the FAI speed engine. It has the same bore in the crankshaft as the FAI speed engine & therefore it requires a .472" bore carburetor. The OS Max 9B (.472" bore) has automatic fuel metering with high & low speed needles. Once the needles are set properly, the engine can be easily throttled up & down. 

One more thing to be aware of. If the tuned pipe has an adequate volume compared to the displacement of the engine (approximately 26 times), you will be able to make the stingers length 13 times its ID.

Jim Allen

 

[RonShaw]

Ill be the third one to say it. Get the SPP quiet pipe from Ron. We tested the Irwin, Hopper, Aerotech and a homemade pipe on the NR, nothing came even close to the SPP. 

Thanks Gabe. I try to keep the 21, 46, and 67 SPP OB pipes in stock at all times. 

 

[Grimracer]

Hi Mitch,

If you can find a  thin walled brass tubing that will telescope inside the ID of of your existing tuned pipes stinger, this would be the easiest method to decrease the ID & increase the total length. Since thin walled rigid brass tubing has a .015" thick wall, very small reductions in the ID of the stinger can be made.  Both things will increase the HP produced & both things will increase the engines operating temperature but not in the same way. Small decreases in the stingers ID will greatly increase the engines operating temperature. This is why you want to make small decreases to the stinger's ID. Large increases in the stinger's length have a less of an effect on raising the engines operating temperature. The telescoping tubings can be held in place with a .026" diameter steel wire by cross drilling both pieces. 

One more important thing when using the Nelson .45 long stroke engine. This is the same engine as the FAI speed engine. It has the same bore in the crankshaft as the FAI speed engine & therefore it requires a .472" bore carburetor. The OS Max 9B (.472" bore) has automatic fuel metering with high & low speed needles. Once the needles are set properly, the engine can be easily throttled up & down. 

One more thing to be aware of. If the tuned pipe has an adequate volume compared to the displacement of the engine (approximately 26 times), you will be able to make the stingers length 13 times its ID.

Jim Allen

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Good post.. thanks for sharing

Grim

 

[Carl Van Houten]

Jim,

I have a question about the picture of your boat. It looks as if you are running a textured bottom. I would think that you have tested the textured bottom against the smooth bottom. You must have seen an improvement by adding it? I haven't ever tried it. Did you find an improvement is handling or speed from using it? I would venture to say it was a handling improvement of some kind maybe in rough water... ?

 

[Jim Allen]

Mike,

There is a machined piece that is added between the cylinders exhaust window (top edge arched)  & the outside edge of the crankcase exhaust window (rectangular shaped). It is held in place between the crankcase & the tuned pipe header. It greatly increases the flow in this critical area. Also notice the machined adaptor mounted to the back side of the 9B carburetor . The two standard mounting logs are machined off the 9B carburetor & four 4-40 SHCP screws are used to hold the carburetor to the machined adaptor. The stock "O" ring is used as a seal at this point. The machined carburetor adaptor provides increased flow into the crankshaft window.  There is also a ramp used in the crankshaft to increase flow in this area. The original venturi clamp screw holds the entire assembly in place.

JA

 

[Grimracer]

Do you worry about fuel collecting on the crankshaft ramp and sending the blobs of fuel into the combustion area?

Great looking work!

Grim

 

[Jim Allen]

Jim,

I have a question about the picture of your boat. It looks as if you are running a textured bottom. I would think that you have tested the textured bottom against the smooth bottom. You must have seen an improvement by adding it? I haven't ever tried it. Did you find an improvement is handling or speed from using it? I would venture to say it was a handling improvement of some kind maybe in rough water... ?

Carl,

I do not run this boat in rough water because it is a very light weight layup. The bottom running surfaces have been coated with West System #423 graphite powder mixed in #105 West System epoxy resin with #206 slow hardener. One thin layer is applied with a foam roller. After cure the surface is lightly block sanded with 800 grit wet or dry paper. The final surface should be "very flat, but not very smooth". On calm water I see a 2 to 3 MPH increase in speed over a slick smooth epoxy painted waxed surface. I do not see any improvement in handling.

JA

Do you worry about fuel collecting on the crankshaft ramp and sending the blobs of fuel into the combustion area?

Great looking work!

Grim

No! This is the same ramp used in the Nelson .45 long stroke Pylon racing engine & the Nelson Fai speed engine. The ramp not only increases high end RPM (29,000 to 32,000) it helps the engine to pipe up.

JA