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flying tomato
09-08-2010, 10:03 PM
Ok, I am in the process of gathering information about Nitrous Oxide to put into my Donzi Hornet III. From what I read, as long as you set it up correctly and don't over HP it, it sounds "fairly" safe.

Looking for some people that have tried it and I want their opinions. Please if you have never used it please don't reply. I want "real" life scenarios. Pls be specific: what HP used, what type of controller did you use (if any), what type of ignition retard did you use. And, of course, what were the results.

Thanks in advance,
Flying Tomato

Just Say N20
09-08-2010, 11:14 PM
1979 18 2+3.
Mercruiser 260 w/Alpha drive (somewhat tired, but solid)
NOS 110 hp - 125 hp kit (the most mild kit they had for a SBC)
Standard mechanical fuel pump, that maintained 7 psi at WOT
The nitrous added 800 rpms.
21" Cleaver went from 4,400 rpms, to 5,200 rpms but the prop slipped a lot so it only picked up about 5 mph.
23" S/S round ear prop (I don"t know what brand of prop it was) went from 4,200 rpms to 5,000 rpms and I picked up 8 mph.


This was all way pre-GPS, but the cleaver ran a speedometer indicated 58 mph without/63 mph with, and the round ear prop ran 58 mph without/66 mph with.

I ran a 10 lbs bottle, and never held the button in for more than 7 seconds at a time. It was an immediate, smile producing blast of acceleration. But if I wasn't blowing by someone in 7 seconds, I let off to preserve the engine.

I never had any engine issues.

Hope this helps.

PlumCrazy
09-08-2010, 11:47 PM
I ran a NOS Sniper wet kit with a 125HP shot on my '88 Baja Sunsport 196 for two seasons. The engine was a 500HP 357ci Chevy with 11.25:1 compression and utilized a MSD ignition retard control box(PN 8970). I pulled out 3-4° of timing with a WOT switch. The boat had an Alpha SS spinning either a Spinelli 26P or a Quicksilver Mirage 23P to 6000 RPM naturally and 6500 on nitrous. The speed gain was exactly 5 MPH. The boat went from 79 to 84 on GPS. I liked the novelty of having the nitrous. People were always shocked to see it on a boat. It was fun, but also expensive filling bottles that only lasted about 30 seconds. You can see it in the background of this pic.

http://img.photobucket.com/albums/v215/dpluhm/Baja/baja2.jpg

A2VeeDub
09-10-2010, 11:39 AM
I currently have a 100 shot on a sbc in a 1972 18 2+3.
I've gotten very similar results as Just say N2O.
I'm running an alpha drive with ~275hp small block.
With a 23" cleaver I go from 4400 rpm at 62 mph gps to ~5200 rpm at 70 mph gps.
Running a full throttle engagement switch with a secondary switch to enable it.
Stock mechanical fuel pump that still delivers 7 psi with nitrous on.
Solenoids wired in line with low fuel pressure cut out.
No timing retard at 100 shot, just 93 octane in the tank. NOS recommends taking out timing at 125 shot and above. I think it was like 3 or 5 degress for every 25 over a 100 shot.
I go through about a 10lb bottle in a season only spraying once or twice per trip out for about 4-7 seconds at a shot.

justleft
09-10-2010, 06:13 PM
The only bummer, it was only 10 seconds worth.

But it was 10 seconds of whop arsh !! :hyper:

Just don't inhale NOx :bonk: Just leaving the dock is really funny.

fysis
09-11-2010, 02:50 PM
Ok, I am in the process of gathering information about Nitrous Oxide to put into my Donzi Hornet III. From what I read, as long as you set it up correctly and don't over HP it, it sounds "fairly" safe.

Looking for some people that have tried it and I want their opinions. Please if you have never used it please don't reply. I want "real" life scenarios. Pls be specific: what HP used, what type of controller did you use (if any), what type of ignition retard did you use. And, of course, what were the results.

Thanks in advance,
Flying Tomato Hello Hornet. How big is your engine and how much compression ratio are you running. Whatīs your goal of using Nitrous. Íīm quite familiar with the stuff since back in the street racingdays in the early 80:s (back then we got the bottles from the lokal hospital by some nurse I dated)and used Phantom solenoids.Even in my Donzi 22 540" i have used N2O "Cheater system" just to see how the boat behaves under more power. Cheaper way than to build an engine and find out thatīs not up to your expectations . I can give you some information of my experiences if you want.:sweden:

flying tomato
09-12-2010, 01:27 PM
Hello fysis,
My engine is a 489 cid. 454 with stroker crank. Aluminum heads, x-treme marine 278 hydraulic cam, demon 850 carb, aluminum stainless marine exhaust. Approx 500 hp. Compression is 10-1. Boat has TRS drive. (I know, not the best for speed)
I am looking for some more speed. I have exhausted all other avenues (eng tuning, props, trim settings). Top speed is 71.
I will only be able to use the spray in short spurts probably 4-8 seconds, as the boat is only 21 ft long and kinda squirrely at speed.

Any advice is appreciated,
Flying Tomato