Nitrous in bleed ports?

**90 5.0** · 09-27-2016, 02:54 PM

I have a block with the bleed fittings for carbs but we have laser injection on it now, the bleed fittings pull vacuum to carbs by intake velocity from behind the liner right?

thinking of an easy way to run a dry shot where all cylinders get same volume. Would it be crazy to try a 6 port manifold and dump the gas into the cylinders through the bleed fitting ports?

**Chaz** · 09-27-2016, 04:31 PM

Ya mean like diz .....

**90 5.0** · 09-27-2016, 05:03 PM

Damn Chaz there's so much going on there I can't tell if that's the from or the back of the motor!!!

that looks like it's in the intake side? But it's hard for me to tell in that pic with all that spaghetti everywhere!

I'm talking about in the carb bleed fittings on the block back half, since there is already a port for each cylinder to the port ? Make sense?

**Chaz** · 09-27-2016, 11:40 PM

It does appear to be a bit "busy" ...

Plumbing into the bleed line hole .... good and bad ...

It's already 1/16 npt , so a nozzle will go right in .... that was easy ..

Spraying after the reeds won't tend to try and keep them open or freeze them . But it will do it's best to create pressure that will be trying to push them shut the entire time the transfers are closed and blowing the charge out of the ex port when they are open.
Where would you aim the nozzle ? The bleed hole is aprox. 3/4 the way up one of the boost ports .
If you used a bottom dump , the charge would go straight across and hit the sleeve in one tiny spot , bounce off and find it's own direction . If you used a 90* nozzle and aimed it up , it would blow right on the the piston most of the time , freeze a small section of the rings for about 60* of the BDC sweep . If you blew it back down the port then that port would become ineffective but make the other three conduits think it's a crisp winter morning . Would the trade off be worth it ?
Spray bars have their own set of issues , especially when you stand them up vertical . I have never been a fan of them , but that seems to be the road most traveled on carb outboards .
Dry shot , no way to retard timing on the hose and two strokes seem to be a recipe for disaster .
Dry to me is only a way to clean up a poor tune-up . If you can stay on the hose for longer than a little blip then the motor is way to fat to begin with . Or if your using it to clean out the excessive fuel and oil that's puddled in the crank case , then how do you know when your one tap of the button too many ... ?
Guys that do have dry systems seem to be around 50 to 75 hp . It use to be , coming up with flow rates was the hard part , now it seems like the hardware is a bigger issue ....

All that being said , it take 330 lbs/hr to support 100 hp worth of fuel . Which works out to be a .052 jet @ 900 psi.
Break that down to a six shooter and you would need a half a dozen .021's to get 330 lbs/hr
So 50 hp = 165 lbs/hr or six .015's 75 hp = 247.5 or .018's
As you can see , the jetting is really small . I guess it's not so bad since it's on the air side . I'm a bit gun shy of small jets because I had a small sliver of plastic from a Jazz fuel cell plug up a .022 fuel jet and it looked like a plasma cutter ripped thru the motor .
The worst would have to be if you didn't service the solenoid and have it do the hissssssssss .... BOOM . Nothing but a thin plastic cowl between you and the shrapnel ... what ever you do , put safety first and I'm sure you'll enjoy having that "passing gear" @ your finger tip ...

**texasvector** · 09-28-2016, 12:05 AM

chaz................i know diddly squat about nitrous...........that being said.

EXCELLENT READ!! needs to be more post like that on this site...and everywhere for that matter...less "my black max wont idle" leave that for boats.net

**90 5.0** · 09-28-2016, 03:06 AM

Chaz thanks for your insite, so you suggest not to try it.

Lookksike I should put a horn on the front and spray my fogger 2 nozzle into it?

**dwilfong** · 09-28-2016, 06:01 AM

Let me pass some thing by ya all wile your all in the mood...............
I am using 3 center WH-15 on my mod 2.5. The reason is I found a good deal on 3 new carbs but thy where all center carbs.
Now the center carbs have the T fitting for the enrichment circuit on them. The ports go in to each venture on the carbs.
So I am setting up the fuel system with a carter pump and by pass regulator for fuel delivery to the eng.
Now on the eng I have a fuel block with one line to each carb also a second block with a sol on it to feed it. This will have one hose going to each T fitting on the carbs with one side of the t blocked off.
This is for the fuel delivery for enrichment to each carb bore.

Have bin tossing around using this to have a stand alone system with its own tank on the enrichment circuit and use Nitromethane.

Nitro makes tones of power even in a supper rich mix........................................

No freeze up and as long as you keep it rich no burn down.
Now will the rotating assembly take it???????????????????????????????
No need for high revs as nitro is liquid toque.

**Slimm** · 09-28-2016, 09:01 AM

I LOVE the idea and I'd try it if I had the equipment. Funny thing is I have thought about the possibility of using those ports for some go fast(er) purpose while inspecting the carbs I have. I know almost nothing about Nitromethane other than it's what we used in some RC cars.

Slimm

Originally Posted by dwilfong

Let me pass some thing by ya all wile your all in the mood...............
I am using 3 center WH-15 on my mod 2.5. The reason is I found a good deal on 3 new carbs but thy where all center carbs.
Now the center carbs have the T fitting for the enrichment circuit on them. The ports go in to each venture on the carbs.
So I am setting up the fuel system with a carter pump and by pass regulator for fuel delivery to the eng.
Now on the eng I have a fuel block with one line to each carb also a second block with a sol on it to feed it. This will have one hose going to each T fitting on the carbs with one side of the t blocked off.
This is for the fuel delivery for enrichment to each carb bore.

Have bin tossing around using this to have a stand alone system with its own tank on the enrichment circuit and use Nitromethane.

Nitro makes tones of power even in a supper rich mix........................................

No freeze up and as long as you keep it rich no burn down.
Now will the rotating assembly take it???????????????????????????????
No need for high revs as nitro is liquid toque.

**97 TWISTER** · 09-28-2016, 09:31 AM

I have a mod 85 Suzuki on a GW invader that was a buddies pet project. He was setting up a set of carbs for Nitro and gave me some fuel with the boat. I did a bunch of reading on Nitro and it certainly make a pile of HP but the learning curve sounds pricey. I found most of the 2 stroke info on quad racers forums. I read a a lot of stories about stretched rod bolts bend rods and complete destruction. I have kinda backed down on the Nitro and am leaning towards nitrous. There is a lot of info available on Nitrous but not done right can also have pricey results. The boat is right on the #'s for our 65mph class but do to all the weight hanging off back it causes the boat to dig deep and come out a bit slow. Over the winter I'm planning on trying to figure out how plumb 35-45hp shot to get the boat rolling. Good read guys and please keep ideas and experience coming. Thanks

**WillySteve** · 09-28-2016, 10:50 AM

Originally Posted by Chaz

It does appear to be a bit "busy" ...

Plumbing into the bleed line hole .... good and bad ...

It's already 1/16 npt , so a nozzle will go right in .... that was easy ..

Spraying after the reeds won't tend to try and keep them open or freeze them . But it will do it's best to create pressure that will be trying to push them shut the entire time the transfers are closed and blowing the charge out of the ex port when they are open.
Where would you aim the nozzle ? The bleed hole is aprox. 3/4 the way up one of the boost ports .
If you used a bottom dump , the charge would go straight across and hit the sleeve in one tiny spot , bounce off and find it's own direction . If you used a 90* nozzle and aimed it up , it would blow right on the the piston most of the time , freeze a small section of the rings for about 60* of the BDC sweep . If you blew it back down the port then that port would become ineffective but make the other three conduits think it's a crisp winter morning . Would the trade off be worth it ?
Spray bars have their own set of issues , especially when you stand them up vertical . I have never been a fan of them , but that seems to be the road most traveled on carb outboards .
Dry shot , no way to retard timing on the hose and two strokes seem to be a recipe for disaster .
Dry to me is only a way to clean up a poor tune-up . If you can stay on the hose for longer than a little blip then the motor is way to fat to begin with . Or if your using it to clean out the excessive fuel and oil that's puddled in the crank case , then how do you know when your one tap of the button too many ... ?
Guys that do have dry systems seem to be around 50 to 75 hp . It use to be , coming up with flow rates was the hard part , now it seems like the hardware is a bigger issue ....

All that being said , it take 330 lbs/hr to support 100 hp worth of fuel . Which works out to be a .052 jet @ 900 psi.
Break that down to a six shooter and you would need a half a dozen .021's to get 330 lbs/hr
So 50 hp = 165 lbs/hr or six .015's 75 hp = 247.5 or .018's
As you can see , the jetting is really small . I guess it's not so bad since it's on the air side . I'm a bit gun shy of small jets because I had a small sliver of plastic from a Jazz fuel cell plug up a .022 fuel jet and it looked like a plasma cutter ripped thru the motor .
The worst would have to be if you didn't service the solenoid and have it do the hissssssssss .... BOOM . Nothing but a thin plastic cowl between you and the shrapnel ... what ever you do , put safety first and I'm sure you'll enjoy having that "passing gear" @ your finger tip ...

Couldn't have said it better myself!!!!!
There is no amount of Dry Shot on a 2 stroke that will not be a disaster!!!!

Alot of People don't realize that Nitrous also takes FUEL and the dry shot works only on a system that has O2 exhaust sensors and an ECU that is capable of enrichening the fuel system when it sees the exhaust gasses are lean!

IMO, best to use Foggers and put them in the Carb Throat, in front of the butterflies or just behind, (just be sure to install it on the side where it doesn't interfere with the butterfly's opening). I've never had a problem with either of these and 1/16 NPT taps are cheap!

**johnmiffco** · 09-28-2016, 11:44 AM

I ran alcy through my merc motors back in the 1980s
to help keep the combustion cooler on the nitrous
always keep the nitrous injection in front of the reeds
whether it was wet foggers in between the carb and reed on the intake
or the old L&S drilled tubes in the intake
as a naturally aspirated motor can only suck in soo much pr stroke
and an opened solenoid never stops flowing
if inject after reeds u choke the air and fuel coming in
as a 900lb """non flammable gas""" fills up the intake track
both directions,,,towards the combustion chamber and back up the intake
so a 900lb expanding gass will choke the intake charge of air and fuel
so stay in front of the reeds ,,,,,,,,as not a good outcome when choke intake charge
and when talking nitromethane
gaylen and I played a lot with it
got to keep in mind nitro is a very long burning fuel with a lot of oxygen content in it as why it makes so much power
still burning out the tuner
late in evening and could see a pretty blue haze on top of water behind the ex outlet on mid on the water,,,,,,,
the oxy content is why alcy is ran with it,,it mixes well and helps cool the extra oxy content
as why top fuel cars have 10' flames out the zoomies
there is a stopping % on a 2 stroke reed motor of how much u can give it
as a 2 stroke has reeds out the track at the carbs,,,,not valves inside the combustion chamber as a 4 stroke
and the long burn will travel back up the intake track and melt out the reeds
not to mention burn the intake charge fuel and oil,,,,,leaving bearing dry and hot
gotta not guess,,,,,gets costly
went through a lot of R&D back then on spray and nitro
so just a couple cents of what I learned,,lol

**olboatman** · 09-28-2016, 12:04 PM

Scribed.... Very Interesting!!!

Gary

**W2F a V-King** · 09-28-2016, 03:57 PM

Also scribed...

I run a dry system on my fuel injected SBC that increases fuel pressure to the fuel rail via the vacuum controlled fuel pressure regulator on the fuel rail.

When the system begins to flow N2O, the controller in my system (NOT the one in the link below) pressurizes the fuel regulator increasing fuel pressure in the fuel rail, in proportion to the amount of N2O shot. The controller monitors bottle pressure and as bottle pressure decreases (during a run as the bottle cools) it matches the decrease proportionally to the fuel pressure regulator, keeping the mixture happy.

Wonder if this type of system would work on a Merc EFI. With some calibration tweaks?

I do know that When the juice is on, it's better to have the motor in the higher rpm's and accelerating, because Like Dave mentioned..It is liquid torque, and it has no mercy on the rotating assembly. So for an out of hole situation, it will be harder on the crank/rods, etc. Than at an accelerating higher rpm.

There are dwell controllers that pulse the solenoids instead of an instant onn/off to soften the begin of the "hit".
http://static.summitracing.com/globa...a5074-snos.pdf

James

**WillySteve** · 09-28-2016, 04:36 PM

Originally Posted by W2F a V-King

Also scribed...

I run a dry system on my fuel injected SBC that increases fuel pressure to the fuel rail via the vacuum controlled fuel pressure regulator on the fuel rail.

When the system begins to flow N2O, the controller in my system (NOT the one in the link below) pressurizes the fuel regulator increasing fuel pressure in the fuel rail, in proportion to the amount of N2O shot. The controller monitors bottle pressure and as bottle pressure decreases (during a run as the bottle cools) it matches the decrease proportionally to the fuel pressure regulator, keeping the mixture happy.

Wonder if this type of system would work on a Merc EFI. With some calibration tweaks?

I do know that When the juice is on, it's better to have the motor in the higher rpm's and accelerating, because Like Dave mentioned..It is liquid torque, and it has no mercy on the rotating assembly. So for an out of hole situation, it will be harder on the crank/rods, etc. Than at an accelerating higher rpm.

There are dwell controllers that pulse the solenoids instead of an instant onn/off to soften the begin of the "hit".
http://static.summitracing.com/globa...a5074-snos.pdf

James

JMHO it would not be worth gambling a scattered engine on whether a dryshot would work, or you could get a dryshot to work, when I'm positive that adding additional fuel via it's own separate fuel system does work!
I've ran an old '78 2.4 175 Black Max to death over 3 years with N2o and never had any powerhead problems, (by running a standard Nitrous PLUS fuel system)......the prop shafts and drive shafts were different stories!!!!
Another JMO is if you can't experience N2o out of the hole all the way up to top RPM's yer missing out by running it!!!!
I sold the old boat and 175 to a friend, (less the N2o), and he ran the crap out'a it for another 4-5 years then sold the boat, never having a wrench on the powerhead!!

**dwilfong** · 09-28-2016, 05:05 PM

Yes a nitro shot would just be a top end thing for sure..........
Not some thing you would use for any amount of time.
You don't need any more air with nitro it carries its own with it. It can be used as a mono fuel with no air at all.
You would not need tones of it to get good results. But it can run away quick if the shot is just right.
Also the chamber would have to be large and cyl pressure kept low as to not blow the heads off. A large shot can hydro lock the eng.
Yes you can dump that much in the eng.

The burn back to the reeds is some thing I have never heard of before. would love to hear more on what has bin tried in the past.
How much has bin dumped? How long did the eng run? Any one dumped strait nitro unmixed?
Some propylene oxide will help with the slow burn rate and may cure the burn back. Have tested propylene and nitro mix a few times with small 2 stroke engs.
Would really like to give it a shot.