small nitrous shot on a 4.3 merc to help plain?

Nice set-up. I am seeing those rims more and more on trucks. :huh:
 
H2ONUT said:
Nice set-up. I am seeing those rims more and more on trucks. :huh:
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yea they are cheap and black. so you can scratch em up and they still look good. perfect rim for a truck imo. i paid $140 canadian per rim. cant do much better than that. :grin:
 
I am with the previous post on the rims. I was looking at putting them on 4-door jeep wrangler unlimited.
 
What was the subject again? :smt017 Oh yeah, nitrous.

I'm just wondering and thought I'd post as a devil's advocate. A small nitrous shot isn't going to hurt that I could see; you didn't say you were going to get crazy with the nitrous and do something mega-horsepower stupid with it. As I read your original post you seem to be wanting just a little extra oomph to get on plane because the 4.3 just can't quite cut it with a full boat load onboard. If you're talking about a constant shot while towing tubing, that's a little extreme..... you wouldn't keep the juice on an auto for extended times either.

A 4.3 is going to have an Alpha 1 outdrive (at least mine does) and I know Alpha 1's are on 5.0/5.7's and other bigger engines. So you squirt a small shot... that doesn't give more oomph than an 8 cyl with the same outdrive. A 30hp wetshot is not going to push your 4.3 above 8cyl hp territory that push a lot of other Alpha 1's so I don't see the problem.

And most 8cyls don't have cavitation either if you have a similar prop. An Alpha 1 comes with 14.5" props but I put a 15" Black Max on mine and it has a LOT more prop area..... I cannot believe it would cause cavitation problems if I had put it under a 5.0/5.7

So, you fill up your boat with all your overweight buddies, hit the juice for a few seconds to get on plane, and then cruise as normal once up on plane. Sounds a like heckuva lot more efficient fix to me than swapping for a bigger engine.

Plus nitrous on water would just be cool :grin:

Now, if you plan to get stupid with it and up the shots, all bets are off. But within reason, I think you're on to something.
 
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GJarrett said:
A 30hp wetshot is not going to push your 4.3 above 8cyl hp territory that push a lot of other Alpha 1's so I don't see the problem.

And most 8cyls don't have cavitation either if you have a similar prop. An Alpha 1 comes with 14.5" props but I put a 15" Black Max on mine and it has a LOT more prop area..... I cannot believe it would cause cavitation problems if I had put it under a 5.0/5.7
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I agree with the Alpha 1 and the extra 30 horses - no big deal. But, the prop on the Alpha 1 is matched to the boat and engine more than the Alpha 1 is. You wouldn't run the same prop on that boat if it had a V-8. I think cavitation could be an issue.

I had a Classic 190 bowrider with a 5.0L V-8, Alpha 1, and Aluminum prop. We used to boat in shallow rivers, and we would occassionally ding a prop. If the shop shaved it down, but didn't build it back up, the boat would run fine and even have a quicker hole shot (like a lower gear). But, if you put all 200+ horses to it, the thing would cavitate fairly easily. Your prop is smaller than the one a V-8 would have in order to allow either engine to hit the proper WOT RPM. Putting an extra 30 HP to it may exceed the prop's ability to bite, and it may cavitate.

If you're using those 30 extra horses to get a heavily loaded boat on plane and it cavitates, you may find it hitting some pretty high RPMs in a very short burst (especially with the throttle control (or lack thereof) with nitrous), and that's not good for your engine. You do not want to run at normal RPMs with little resistance let alone above red line. I'm all for fun stuff, but this one may be a little risky.
 
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I want videos! Let us all see. One good thing is your boat will self extinguish at the waterline, but there is one problem. How are you going to run away from it? Good luck.
 
You could upgrade the carb and manifold from a 2 bbl. to a 4 bbl. just like the 4.3LXs for a 20hp gain . . .
 
Get a "High Five" prop with a 19" pitch. I think GJarrett was eluding to a 14.25" or 15" Diameter not Pitch prop.
The 19" high Five in a 185 w/4.3L should provide you solid "SAFE" performance.

I don't think NOS has a safe place on boats either.
 
Yep that was diameter not pitch.... 15 pitch would be insane! The High Five series prop might indeed be a great fix.

rktktpaul could also be onto something.... I've got the 4bbl 4.3LX in a boat a heckuva lot bigger than yours and with the 15" diameter 18 pitch Black Max prop have a little trouble planing out with five - six adults and a full load onboard, but she still does get up and do it. As was posted, the extry barrels are supposed to be good for another 20 hp or so (mine's 210hp), but I assumed that a 2005 engine would not have carbs on it (?) what is your configuration (carb/MPI/EFI)?

If you do have a 2bbl and want to look at an extra 20hp I do have an extra 4bbl carb for my 4.3. There's nothing at all wrong with it but I had a totally new engine replacement last year (including a new carb) so now I have an extra one.
 
Nehalennia said:
Get a "High Five" prop with a 19" pitch. I think GJarrett was eluding to a 14.25" or 15" Diameter not Pitch prop.
The 19" high Five in a 185 w/4.3L should provide you solid "SAFE" performance.

I don't think NOS has a safe place on boats either.
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I agree with the prop approach to this situation. But in general if one decided to properly install a nitrous system on a boat I don't know why they would be unsafe.
 
The last year of the piston powered Oh Boy Oberto had nitrous bottles lined up like peas in a pod. Course those WW2 fighter engines were designed for War Emergency Power with water injection too.
 
You are suggesting a short term solution to a long term problem.

You might get 1 maybe 2 seasons with the NOS addition. Then the engine will break due to the added stresses. Cast pistons and rods are suspect and it will be the added forces and not high rpms that will result in failed components.
Then you will probably upgrade to a 5.7 engine to replace the blown 4.3 at which point you will probably find the level of performance you want.

I do applaud your creative solution on a short term basis though!
 
DAMN.... I read from the beginning into page two and saw Hampton... And thought he is back?...then looked at the date.... I hate when this happens
 
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