NOS question
06-29-2002, 08:07 AM
#21
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I use to run NOS on a 18 Donzi I had. 175 HP shot would give me 10 mph.
I built the motor for NOS. 351W Ford, .030 over, good rods, roller cam, HD bearings, worked cast iron heads, forged pistons and two fuel systems. One for the carb and one for the NOS. It was a blast. You would be WOT and your fellow racer would be trimming out and creeping by, knowing you were out of motor, and presto hit the button, step right out away from him. What a rush.
Also, worked great on take-off. Could give the O/B guys something to talk about. Hit the button just as the bow started to drop.
Use to run it 30 sec. or so each shot. Had a 20 lb. bottle under the floor storage hatch.
Never had engine problems.
I built the motor for NOS. 351W Ford, .030 over, good rods, roller cam, HD bearings, worked cast iron heads, forged pistons and two fuel systems. One for the carb and one for the NOS. It was a blast. You would be WOT and your fellow racer would be trimming out and creeping by, knowing you were out of motor, and presto hit the button, step right out away from him. What a rush.
Also, worked great on take-off. Could give the O/B guys something to talk about. Hit the button just as the bow started to drop.
Use to run it 30 sec. or so each shot. Had a 20 lb. bottle under the floor storage hatch.
Never had engine problems.
06-30-2002, 11:28 AM
#22
Registered
I've never hurt a motor using nitrous that I didn't know before hand I was going to hurt !!!
Generally you need about 15 additional HP to pick up 1 MPH so to go from 80 to 90 plus you're looking at a good amount of N2O, plus the fact that you'll most likely have to change props running that much HP. When I work on Drag cars it's very common to have to change the torque converters when using N2O. My old car would need a 6,000 RPM stall speed w/o N2O, and a 3,800 with it.
C_Spray. You may want to double check with NOS, but that tune-up seems way off for a high pressure (F/I) N2O set up.
Generally you need about 15 additional HP to pick up 1 MPH so to go from 80 to 90 plus you're looking at a good amount of N2O, plus the fact that you'll most likely have to change props running that much HP. When I work on Drag cars it's very common to have to change the torque converters when using N2O. My old car would need a 6,000 RPM stall speed w/o N2O, and a 3,800 with it.
C_Spray. You may want to double check with NOS, but that tune-up seems way off for a high pressure (F/I) N2O set up.
07-01-2002, 10:54 PM
#23
1975 X-18 Donzi, Arneson
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C-Spray,
The jets you quoted are for a low fuel pressure (5-6lbs) set up. You need to install a second low pressure fuel pump for the Nitrous or a 2nd fuel regulator to lower the fuel down to 6lbs. I have a kit if you want to try it out for the run. George (203)258-5222
The jets you quoted are for a low fuel pressure (5-6lbs) set up. You need to install a second low pressure fuel pump for the Nitrous or a 2nd fuel regulator to lower the fuel down to 6lbs. I have a kit if you want to try it out for the run. George (203)258-5222
07-02-2002, 12:53 PM
#24
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Wild Horses,
Well it was a stock short block w/ stock heads (ported). It was an 85 , so no fuel injection to deal with.
Proshifted (no syncros , straight cut Liberty gears) T-5, 4:10 gear.
It would have went into the 11's if I would have put 4.56's in it, but it was set up for the spray.
Rumrunner,
I'm surprised to hear about having to change to a looser converter. The added torque usually would flash the converter higher. Although if it wasn't a special Nitrious converter it would usually damage it.
Well it was a stock short block w/ stock heads (ported). It was an 85 , so no fuel injection to deal with.
Proshifted (no syncros , straight cut Liberty gears) T-5, 4:10 gear.
It would have went into the 11's if I would have put 4.56's in it, but it was set up for the spray.
Rumrunner,
I'm surprised to hear about having to change to a looser converter. The added torque usually would flash the converter higher. Although if it wasn't a special Nitrious converter it would usually damage it.
07-02-2002, 07:30 PM
#27
Registered
26Scarab:
No, I was much tighter with the nitrous converter. Almost 2,200 RPM.
Meyer:
The engine is going to "pull" the N2O regardless of where you mount the nozzle. It doesn't matter how much suction your engine has the N2O has 1000PSI. But by the throttle body should work fine.
No, I was much tighter with the nitrous converter. Almost 2,200 RPM.
Meyer:
The engine is going to "pull" the N2O regardless of where you mount the nozzle. It doesn't matter how much suction your engine has the N2O has 1000PSI. But by the throttle body should work fine.
07-04-2002, 12:58 PM
#28
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Thanks for the input!
jdnca1 - It's a 28' BatBoat. I expect to see about 7-8 mph, since I've ran 6 mph faster with a 70 hp stronger engine in the past.
RumRunner - I may have mis-read the NOS website, but I could swear those specs were for an EFI system. Maybe they included a step-down fuel regulator???? I've got the props I need - they've been re-pitched from 29.5" to 31", and gave me the right numbers with the 600.
GEOO - Why am I not surprised that you would have a system?
Anyway, this particular engine still has the stock fuel pumps on it. There is a 6 psi low-pressure pump and a 40-42 psi high pressure pump. The only question is whether or not a pump designed for the original 415 hp could stilll supply enough for the nitrous shot. (It does just fine for the 530 hp I'm running now....)
UNFORTUNATLEY - This now all for nothing, as I will not be able to attend the Radar ShootOut due to work obligations.
(The trophy is there for the taking, boys.) However - next year I'll be back with the 100 hp nitrous shot on the 600 and an upgraded drive and taller gear ratio to handle the extra oomph. 
With 720 hp, these boats have run 107 mph, so I'd be happy to "settle" for 102......
RumRunner - I may have mis-read the NOS website, but I could swear those specs were for an EFI system. Maybe they included a step-down fuel regulator???? I've got the props I need - they've been re-pitched from 29.5" to 31", and gave me the right numbers with the 600.
GEOO - Why am I not surprised that you would have a system?
Anyway, this particular engine still has the stock fuel pumps on it. There is a 6 psi low-pressure pump and a 40-42 psi high pressure pump. The only question is whether or not a pump designed for the original 415 hp could stilll supply enough for the nitrous shot. (It does just fine for the 530 hp I'm running now....)UNFORTUNATLEY - This now all for nothing, as I will not be able to attend the Radar ShootOut due to work obligations.
(The trophy is there for the taking, boys.) However - next year I'll be back with the 100 hp nitrous shot on the 600 and an upgraded drive and taller gear ratio to handle the extra oomph. With 720 hp, these boats have run 107 mph, so I'd be happy to "settle" for 102......
__________________
Retired! Boating full-time now.
Retired! Boating full-time now.
07-04-2002, 11:11 PM
#29
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TMTHUNDER
From reading the posts, your motor has all good internal parts, including heads. Don't waste money on ported heads, unless you are planning on upgrading to a blower setup.
I use a TopGun nitrous kit on my blown 540 1100 hp motor. The kit ranges from 100 hp - 300 hp, I have used all stages. If you have the proper fuel for the nitrous, then the system will work fine. You do not need to rejet carb. the nitrous has it's own supply. If you run 100 - 150 shot nitrous, your stock fuel pump will be adequate. I have several buddies that I set it up on their boat motors. And their motors have been going for 3-5 years without breakage or problems.
Your rpm range needs to be 3000 + before nos is activated. The mid range pull to top end is AWESOME!!! Your motor will spin up to 6000 rpm no problem. Just remember once you put it on, you will eat up a bottle in a quick hurry.
I know when I hit the button I laugh all the time. What a rush! If you are running 36 degrees timing in retard timing to 33-34 degrees, no need to change plugs. Also nitrous loves a low compression motor, you will get more of the effect. NOS is not dangerous if its all by itself, when it mixes with gas then it becomes dangerous.
I hope this helps you in deciding whether or not to get a system.
Try Top Gun.
Good luck, if you have any questions, let me know!
SAM
From reading the posts, your motor has all good internal parts, including heads. Don't waste money on ported heads, unless you are planning on upgrading to a blower setup.
I use a TopGun nitrous kit on my blown 540 1100 hp motor. The kit ranges from 100 hp - 300 hp, I have used all stages. If you have the proper fuel for the nitrous, then the system will work fine. You do not need to rejet carb. the nitrous has it's own supply. If you run 100 - 150 shot nitrous, your stock fuel pump will be adequate. I have several buddies that I set it up on their boat motors. And their motors have been going for 3-5 years without breakage or problems.
Your rpm range needs to be 3000 + before nos is activated. The mid range pull to top end is AWESOME!!! Your motor will spin up to 6000 rpm no problem. Just remember once you put it on, you will eat up a bottle in a quick hurry.
I know when I hit the button I laugh all the time. What a rush! If you are running 36 degrees timing in retard timing to 33-34 degrees, no need to change plugs. Also nitrous loves a low compression motor, you will get more of the effect. NOS is not dangerous if its all by itself, when it mixes with gas then it becomes dangerous.
I hope this helps you in deciding whether or not to get a system.
Try Top Gun.
Good luck, if you have any questions, let me know!
SAM
