improve on dual cooling

[Freakrider]

My two water lines from the pump go to each side of the exhaust manifold...but I heard that running one of those lines from the pump to only to cool the pipe is better ? and then you run the other pump line to a "y" connection at the manifold ? According to an engine builder this will make your cylinders run much cooler ?

 

[Mike W]

Thats how I had mine ran but I switched back to single cooling. The water comming out of the pissers were luke warm. Deffinatelly not hot enough. Worked too well for my setup.

 

[SuperJETT]

Dual cooling in a split setup is how I run mine. One line for the engine, one for the pipe. You can adjust one without affecting the other.

As for the water not getting warm enough, that's why you run restrictors to get ~120F coming out of the engine.

 

[#ZERO]

Dual cooling lines are mainly used as a safety precaution in case one of the lines happens to get clogged up.

A single line system will cool the engine more then adequate but if the line happens to get blocked and you don't notice the pissers are not working, the engine will cook.

It a good idea to keep the head pipe as hot as possible so it won't rob any horsepower and that's why most people run two lines to the exhaust manifold with restrictors before the pissers.

Plumbing the exhaust manifold with a Y or T-fitting is a great idea if you're running single cooling because it makes the temperature more constant on each cylinder.

 

[freestylegeek]

...
It a good idea to keep the head pipe as hot as possible so it won't rob any horsepower...

I've found just the opposite. I run my exhaust as cool as possible so that I can run the pipe as dry as possible and still get good low-end. I'm also running a mod chamber, so I need to compensate for the shorter length. Maybe it's a northern thing...

 

[Mike W]

Dual cooling lines are mainly used as a safety precaution in case one of the lines happens to get clogged up.

A single line system will cool the engine more then adequate but if the line happens to get blocked and you don't notice the pissers are not working, the engine will cook.
It a good idea to keep the head pipe as hot as possible so it won't rob any horsepower and that's why most people run two lines to the exhaust manifold with restrictors before the pissers.

Plumbing the exhaust manifold with a Y or T-fitting is a great idea if you're running single cooling because it makes the temperature more constant on each cylinder.

True, but I'm always keeping an eye on the pissers...Um..That didn't come out right

 

[#ZERO]

I've found just the opposite. I run my exhaust as cool as possible so that I can run the pipe as dry as possible and still get good low-end. I'm also running a mod chamber, so I need to compensate for the shorter length. Maybe it's a northern thing...

By making the pipe dryer you're just making the chamber warmer and hotter exhaust gases exit the system faster through decreased density and increased exhaust scavenging is produced.

:scratchchin: Interesting you would think by making the head pipe hotter and running a dry exhaust would produce the most horsepower overall.

 

[freestylegeek]

...you would think by making the head pipe hotter and running a dry exhaust would produce the most horsepower overall.

That's absolutely true, but only at peak RPM. I want the biggest torque possible from 4500-7000 RPM. A slow moving exhaust wave will help at the lower RPMs. The reason I want the chamber dry is to keep the waterbox dry as well. Also, with the higher temperature difference between the cool water and the hot exhaust, I'm able to remove more heat from the exhaust and slow the wave down. Yes, I realize by remobving heat I'm removing energy (and thereby removing horsepower), but that return wave is useless if it's slaming up against the side of the piston.

Maybe I'll have to bite the bullet and get a stinking limited chamber...

 

[Freakrider]

I am wondering which set up will be best to keep cylinders cooler for warm summer water to help avoid high compression deto.

 

[ANT]

I ran my exhaust colder once and lost power, definetly more poser when you run the screw closed more. I have a 1/4 on top, 1/8 middle, closed bottom, tryed plaing with it a little and less power. Also have a jetworks valve.

 

[Brenden]

i had single cooling last year but tapped for dual this winter idk if it will rob me of power or not? malone setup my headpipe one day he was at the lake
he put it at 2.5 on the top and like i had 1/4 on the bottom and i noticed a big difference once he went out 2.5 but im questioning if the dual will affect that now that i read this

 

[SuperJETT]

i had single cooling last year but tapped for dual this winter idk if it will rob me of power or not? malone setup my headpipe one day he was at the lake
he put it at 2.5 on the top and like i had 1/4 on the bottom and i noticed a big difference once he went out 2.5 but im questioning if the dual will affect that now that i read this

Yes it will affect it, unless you make some other changes. Adding a second line will increase the pressure in your system, so that 2.5 turns out screw will flow a lot more water which will cool the exhaust more and put more water in the waterbox. You just need to readjust the screw.

 

[DaUpJetSkier]

so on say a factory type 4 pipe (dry pipe) for best bottom end does it matter if the pipe is cold or hot, I just ran dual cooling fall of last year and I think i need some restrictors for spring and fall cuz both pissers were just warm.

 

[#ZERO]

I am wondering which set up will be best to keep cylinders cooler for warm summer water to help avoid high compression deto.

.
In the automotive world, a few racing teams have implemented reverse cooling systems on the ultra high compression, high boost forced induction engines to keep their cylinder heads' combustion chamber from developing hot spots, which can lead to detonation. I've heard that some racing teams were able to run extremely high boost pressures with this type of system that were not possible with conventional cooling systems. The heads would always develop what's called nucleate boiling, where the coolant actually boils off inside the cylinder head impeding the cooling process in that area, causing even more hot spots, and eventually causing detonation or cracks in the combustion chambers.

I'm just wondering if anyone has tried this with jet-ski engines. You almost always see detonation around the edges of the domes and on the top edges of the pistons when it occurs. It seems like you would be able to run higher compression with smaller cc domes by cooling them first to eliminate any hot spots. The only problem that I can foresee with this setup is, after starting a heat-soaked engine, there might be a possibility of cracking the domes with the sudden rush of cool water. This setup may not work with certain types of cylinder heads because some have restrictor holes built into the head shell, but I think it might be worth a try.

It's a very simple cooling circuit where two lines come into feed the cylinder head and exit through the exhaust manifold. Then the bottom of the head pipe gets fed with warm water, and then dumped into the stinger inlet with the excess water going overboard. There will probably be no need for cooling restrictors because it only uses one overboard bypass fitting.

Here's a diagram of the cooling line routing.
.

 

[Freakrider]

I believe some newer corvettes run reverse cooling...I too wonder if any of the jet ski engine builders have tried this ? If it would work it would help in the warm summer time water.

 

[Freakrider]

Quick google search...The Corvette LT1 used a reverse-flow cooling system which cooled the cylinder heads first, maintaining lower cylinder temperatures and allowing the engine to run at a higher compression than its immediate predecessors.

 

[marz831]

That seems like an interesting idea especially for us Gulf riders when water is near 90 degrees in the summer time.

Would running the cooling in this manner put cold water riders at higher risk for cold seizures?

 

[#ZERO]

That seems like an interesting idea especially for us Gulf riders when water is near 90 degrees in the summer time.

Would running the cooling in this manner put cold water riders at higher risk for cold seizures?

Since there is only one pisser fitting you could easily install a 2mm~3mm restrictor for the cold water riders if needed.

 

[freestylegeek]

Since there is only one pisser fitting you could easily install a 2mm~3mm restrictor for the cold water riders if needed.

Instead of a restrictor, a 5-10 psi check valve would be really nice. That way you could keep water in the cooling jackets (and head) so that you wouldn't get that initial blast of ice cold water.

It's definitely something to think about. I'm just not sure I'd want to try it on a custom 8mm Lamey stroker...

 

[Mike W]

.
In the automotive world, a few racing teams have implemented reverse cooling systems on the ultra high compression, high boost forced induction engines to keep their cylinder heads' combustion chamber from developing hot spots, which can lead to detonation. I've heard that some racing teams were able to run extremely high boost pressures with this type of system that were not possible with conventional cooling systems. The heads would always develop what's called nucleate boiling, where the coolant actually boils off inside the cylinder head impeding the cooling process in that area, causing even more hot spots, and eventually causing detonation or cracks in the combustion chambers.

I'm just wondering if anyone has tried this with jet-ski engines. You almost always see detonation around the edges of the domes and on the top edges of the pistons when it occurs. It seems like you would be able to run higher compression with smaller cc domes by cooling them first to eliminate any hot spots. The only problem that I can foresee with this setup is, after starting a heat-soaked engine, there might be a possibility of cracking the domes with the sudden rush of cool water. This setup may not work with certain types of cylinder heads because some have restrictor holes built into the head shell, but I think it might be worth a try.

It's a very simple cooling circuit where two lines come into feed the cylinder head and exit through the exhaust manifold. Then the bottom of the head pipe gets fed with warm water, and then dumped into the stinger inlet with the excess water going overboard. There will probably be no need for cooling restrictors because it only uses one overboard bypass fitting.

Here's a diagram of the cooling line routing.
.

If you think about it, it seems like if you run it that way you will have air pockets with the water flowing down. You will want to run it into the manifold so the flow will be up out of the head. The same for the pipe, water in at the bottom of the headpipe and exit out the top. Thats just the way I do it.