Coffman Sizzler setup and tuning

[King Kang]

That way above isolates the head/manifold cooling from the pipe cooling. By watching your pissers, you would know where you have a problem if you have a clog, etc. The head pipe is routed backwards in the diagram above- you could switch the entry/exit lines if you want a slightly cooler exhaust.

Edit: Since the water is coming directly into the head pipe, it might be too cold if you reverse the direction. Honestly, it might be too cold either way since the pipe is designed to get water that has already passed through the manifold and out of the head.

 

[King Kang]

Here's another way you could do it. It requires less T connections and provides more cooling to the exhaust manifold. Maybe this way is better for a race or long haul application? Again, see how the water flow in the head pipe is reversed when compared to the first diagram?

 

[johnboy72]

Hi guys
That's brilliant thanks. The second pic looks like how I had my protect f pipe hooked up . With the jetworks valve at the bottom to dry the waterbox out

 

[joecef]

I enjoy these pipes. It hit very close to the same as my b pipe did. And the best part is they're quarter of the price

 

[joecef]

Anyone have anything on a duel cooling on a stock head?

 

[Quinc]

Anyone have anything on a duel cooling on a stock head?

Drill a hole and tape it for an npt fitting.

 

[King Kang]

I made some diagrams showing some viable cooling setups for sizzler pipes.



Here is a link to a pdf with them all included.

 

[Quinc]

I made some diagrams showing some viable cooling setups for sizzler pipes.

View attachment 311047 View attachment 311048 View attachment 311049 View attachment 311050 View attachment 311051 View attachment 311052 View attachment 311053 View attachment 311054

Here is a link to a pdf with them all included.

Be interesting to run these different combos and see how it effects the water spraying into the head pipe. Might also be worth taping the hole in the headpipe and adding difference sized low jets to it.

 

[King Kang]

I thought I'd follow up on this thread with some recent pipe maintenance that I did. I started to notice exhaust coming through my pisser, and saw that two of my cooling lines were turning black (The lines leading out of the head pipe.) The line connecting the head to the head pipe was still clear, which lead me to believe that my head pipe bolts were loose and the seal between the head pipe and the manifold was letting water and exhaust mix. After tightening down my three bolts, no more smoke came out the pisser, and the ski accelerated better.

I wasn't planning replacing my water lines, but it turns out that I really needed to. One of my lines was on the verge of total failure (the one going to the pisser) because it had been rubbing against the line that goes to the stinger. Both were probably weakened by the exhaust that had been leaking into them too. They were the typical, cheap clear water lines that many people run, and I had only been running them for about two seasons. They were replaced with Eaton lines.

 

[Quinc]

I like the clear pvc lines from home depot. Cheap and fairly stout.

 

[johnboy72]

Hi guys
Here's my new pipe
Looking forward it fitting it . But got to build my ski first

 

[Patrick Star]

Any base line for a 61x/61x stock 701? Or just run with the 650 jetting on the Coffman instructions?

 

[Quinc]

Start with 125L 150H and 24psi pop off.

 

[Patrick Star]

Any ideas on how to run the sizzler with the stock waterbox? I have the pipe with the curve in it.

Sent from my SM-N900T using Tapatalk

 

[orangefinger]

I Like all the different cooling diagrams nice !!

I personally would stir away from any T going into the manifold and 2 singles coming out of the head, without further restrictors in overboard water bypass and even difference within the lines coming out of the head I think its a culprit for a lot of hot air .....not hot water

 

[Req]

Does anyone know the peak rpm the sizzler is tuned for? I imagine its around 6500 rpm. I am porting this winter and and I have specs for 6500 and 6800 rpm and I am trying to figure out which spec to use.

 

[kevbo]

Does anyone know the peak rpm the sizzler is tuned for? I imagine its around 6500 rpm. I am porting this winter and and I have specs for 6500 and 6800 rpm and I am trying to figure out which spec to use.

My 701 with 182 degrees open exhaust will not rev over 7000. Low end was soggy when propped at 6800. I flattened out the impeller for good response and it turned just under 7K. Top speed was the same in smooth water. The pipe works well with low ports.

 

[Quinc]

Does anyone know the peak rpm the sizzler is tuned for? I imagine its around 6500 rpm. I am porting this winter and and I have specs for 6500 and 6800 rpm and I am trying to figure out which spec to use.

I dont think mine ever saw above 6700 with a solas repitched from 14.7/18 to 13/15

 

[Req]

I dont think mine ever saw above 6700 with a solas repitched from 14.7/18 to 13/15

On my stock 701 with head last season I was getting around 6700 according to my hardline tach, and that was with a 9/15 concord. I am hoping to get about 7k or a bit more out of this engine. I am going to ceramic coat the pipe and run it pretty hot to shorten the perceived tuned length and get it into the pipe a bit more at higher rpm. I will pitch the prop up till it stops slipping, I imagine 11/17 will be where I end up depending on how much the motor rips.

My 701 with 182 degrees open exhaust will not rev over 7000. Low end was soggy when propped at 6800. I flattened out the impeller for good response and it turned just under 7K. Top speed was the same in smooth water. The pipe works well with low ports.

My porting I am doing is a bit higher than most however I am going to be running total loss with this engine, I think I can get away with it using lots of timing and reverse jetting. If I run the pipe hot as I said I can tune it to stuff the exhaust port at the right time.

Exhaust duration 188 degrees
Transfer duration 124 degrees
Blowdown 32 degrees
I can move the peak HP range between 6500 and 6800 depending on how I radius the exhaust port.

So it seems that most people are getting about 6500-6700 out of the sizzler. Quinc, how did the short tail cone effect your rpm or are you still using it?

 

[kevbo]

Im sure that it will rev higher with a taller port and/or shorter tuned length, my porting was 120/182. Once you get the pump load light enough for good response the pipe will go rich and wont rev much more. Small CC engines struggle getting on the pipe with much more than a 9-15. A programmable ignition and high compression will help a lot with that issue allowing a little steeper prop.