Nitrous Set-Up

« **on:** February 11, 2016, 06:28:48 PM »

I decided to move these posts so I can find them easier...

I got this in the mail a couple days ago. I am going to add a 175 HP shot.

78Southwind
What's the best way per cubic dollar to retard the timing? I currently have a 6M-2 box. I have been looking at the Programmable Timing Computer since it's a good price but it looks like you have to lock out your distributor. I really don't want to lock out the timing. So now I am leaning towards the Digital Retard Control or a 6 plus. Any other ideas?

Also, I want to use my claysmith fuel pump (14 to 16 psi) to fuel both the main fuel system and the nitrous fuel system. I am looking at running two fuel regulators and dead head them at 6/7 psi. I also want to run a fuel safety switch on the nitrous fuel system. For the electrical, I am going to run a toggle switch to arm the nitrous system then a microswitch set for full throttle and a nitrous push button. Yada Yada... So does this sound good?

capogniracing
Just went/going through the same thing. I was thinking of a msd-6425 ignition and a msd- 8970 retard. A magnafuel 500 pump running both regulators. And I'm still gonna have locked out timing and a crank trigger. I would love to go with the Msd 6520 and think this is the best dollar for dollar but I need to be able to retard atleast 11 degrees and the 6520 only is capable to retard 9.9 which would work great for your set up. And maybe run a seperate fuel pump for nitrous to avoid a possible lean out. That's my 2 cents.

78Southwind
Ok, so you have to lock out your timing on the msd- 8970 retard box too. If I am running a fuel safety switch to the solenoids (say set 6 psi) should I really have to worry about a lean condition?

capogniracing
Andy gave me a full lock out dizzy and with a safety switch I would think your good to go. Those clay smith are around 140gph right??

jyeager
6 lbs is good for the safety switch. Start with retarding 2 degrees for every 50 hp shot of nitrous. That will give you a good base line for tuning. 👍👍👍👍
I don't like using the same fuel pump for both nitrous and motor but that's me. I use a Holley blue for the nitrous side and now a aeromotive with a bypass for the motor side.

78Southwind
I can see using a separate fuel system for racing but it just doesn't make sense to me for play. If you're running a safety switch then the nitrous won't fire unless you've got good fuel pressure. Maybe I will do some more homework and see what I find. I plan on running 78/78 fuel and nitrous jets with a 6°-8° retard. I am thinking about running one of my gunnel tanks with a mixture of 91/110 and just switch to that tank when I want to run a nitrous pass. Edelbrock says to use 92 octane pump gasoline or better with 175 HP shot.

jimpen
That jetting would be real fat.

78southwind
That's what came with the kit and what Edelbrock suggests.>>?

Flusher
What about when the fuel pressure drops as the demand increases after the N2O fires?

jyeager
I agree. i used the normal squared jetting 2 passes and dumped down the fuel side because it was so fat. It killed my plugs The recomended jetting from Edelbrock and NOS is a fat tune up for sure. Also spark plug gap plays a good role in the tune.

78Southwind
Interesting thanks...

« **Reply #1 on:** February 11, 2016, 08:03:40 PM »

Here is my current engine:
468 Chevy Mark IV, 4 bolt block, forged steel crank, 7/16-inch rod bolts, forged pistons, Cam Kit XM278H-12, hydraulic lifter,
Edelbrock Marine Cylinder Heads 61459, ARP Head Bolt Kit, RPM Air Gap intake, Holley 830, 9.6:1 Compression.
Probably making somewhere around 470 HP @ 4,800 RMP's. Detailed A/B MPD impeller.

I am thinking that if I stay at a 200 HP shot or under this engine should handle the power. What do you guys think?

So I am still in the process of buying parts. I just recently picked up a Victor Jr. intake which will allow a bigger shot of nitrous than my Air Gap. I also picked up a Holley 950 HP XP. I am not sure if the 950 will be too big for my current set-up but my engine can always grow into it.

« **Reply #2 on:** February 11, 2016, 08:40:34 PM »

I also ended up going with a MSD 6+.

« **Reply #3 on:** February 12, 2016, 12:00:53 AM »

I am kind of on the fence about using my Mechanical fuel pump for both sides. It's a 140 GPH (14 to 16 psi) Clay Smith. Anyone want to comment? Bostick you out there? Maybe I will call Clay Smith and see what they say.

I have seen others recommend to use a Holley Blue for the nitrous side. But I just can't get the image out of my head of Paul Kane throwing his second failed Holley Blue about three hundred feet in the parking lot of the AVI during the Classic Boat Beach Bash out of my mind.

Once I decide what I am going to do fuel pump wise I can come up with a plan for plumbing. I also need to buy a Edelbrock/Glycerin-filled mechanical nitrous system pressure gauge, Edelbrock / Momentary contact push button and Edelbrock PSI nitrous fuel pressure safety switch.

« **Reply #4 on:** February 12, 2016, 08:07:24 AM »

My two cents, and its worth about that...

I'd run either the safety switch, or a second pump. Lets face it, you wont spray EVERY time the boats out, and when you do, i cant imagine itll be an all day deal. I think you should be fine.

Is it the preferred setup? No. But will it work? I believe it will.

I run one single magnafuel 275 for both

« **Reply #5 on:** February 13, 2016, 12:04:46 PM »

Quote from: steves86ta on February 12, 2016, 08:07:24 AM

My two cents, and its worth about that...

I'd run either the safety switch, or a second pump. Lets face it, you wont spray EVERY time the boats out, and when you do, i cant imagine itll be an all day deal. I think you should be fine.

Is it the preferred setup? No. But will it work? I believe it will.

I run one single magnafuel 275 for both

Yes, I thought the use of a safety switch would prevent a lean condition caused by a drop in fuel pressure. But Flusher had a comment that has been making me think this out a little more. He asked what about when the fuel pressure drops as the demand increases after the N2O fires? I would think that with a fuel pressure safety switch if at anytime there's a drop in fuel pressure the nitrous will be shut off. So if there is a drop in fuel pressure say 6 PSI to 5 PSI and it takes a fraction of a second for the chain of events to happen (shutting off the nitrous) will this cause engine damage? Am I missing something here?

I know Squirtcha? (Dan) on the boards set-up his nitrous system using a Clay Smith Pump feeding two Holley 750's and the nitrous fuel side. I am not sure if he used a safety switch though. I sent him a PM but he doesn't come on the boards much any more.

« **Reply #6 on:** February 13, 2016, 12:27:23 PM »

Quote from: 78Southwind on February 13, 2016, 12:04:46 PM

Yes, I thought the use of a safety switch would prevent a lean condition caused by a drop in fuel pressure. But Flusher had a comment that has been making me think this out a little more. He asked what about when the fuel pressure drops as the demand increases after the N2O fires? I would think that with a fuel pressure safety switch if at anytime there's a drop in fuel pressure the nitrous will be shut off. So if there is a drop in fuel pressure say 6 PSI to 5 PSI and it takes a fraction of a second for the chain of events to happen (shutting off the nitrous) will this cause engine damage? Am I missing something here?

I know Squirtcha? (Dan) on the boards set-up his nitrous system using a Clay Smith Pump feeding two Holley 750's and the nitrous fuel side. I am not sure if he used a safety switch though. I sent him a PM but he doesn't come on the boards much any more.

Well you should set your nitrous fuel regulator flowing fuel. So yes it'll be a tad rich on the hit but then flowing should be what you need.

My nitrous fuel gauge reads about 9 psi resting but flows 6.5 psi

« **Reply #7 on:** February 13, 2016, 12:52:15 PM »

Quote from: steves86ta on February 13, 2016, 12:27:23 PM

Well you should set your nitrous fuel regulator flowing fuel. So yes it'll be a tad rich on the hit but then flowing should be what you need.

My nitrous fuel gauge reads about 9 psi resting but flows 6.5 psi

Yes, I have read that you should flow it. But that's the kind of stuff that I am talking about that maybe I am missing.

« **Reply #8 on:** February 13, 2016, 01:41:27 PM »

Yeah I'd you flow it. I would not worry about your pump

« **Reply #9 on:** February 13, 2016, 05:16:39 PM »

Quote from: steves86ta on February 13, 2016, 01:41:27 PM

Yeah I'd you flow it. I would not worry about your pump

Ok, so what I have read is that nitrous side fuel pressure will creep up due to line pressure until the fuel solenoid opens and then the pressure drops significantly. So is your gauge reading 9 PSI the entire time or just before the fuel solenoid opens? So the discrepancy between the gauge 9 PSI and flow gauge 6.5 PSI is due to both line pressure and jet size?

So error on the fat side by setting the flowed nitrous side fuel pressure at 6.5 PSI and set fuel pressure safety switch at 6 PSI. So imagine you need to flow the fuel pressure safety switch as well?

« **Reply #10 on:** February 13, 2016, 05:26:02 PM »

Quote from: 78Southwind on February 13, 2016, 05:16:39 PM

Ok, so what I have read is that nitrous side fuel pressure will creep up due to line pressure until the fuel solenoid opens and then the pressure drops significantly. So is your gauge reading 9 PSI the entire time or just before the fuel solenoid opens? So the discrepancy between the gauge 9 PSI and flow gauge 6.5 PSI is due to both line pressure and jet size?

So error on the fat side by setting the flowed nitrous side fuel pressure at 6.5 PSI and set fuel pressure safety switch at 6 PSI. So imagine you need to flow the fuel pressure safety switch as well?

Yes sir you assume correctly

My fuel side will read 9 psi or so, until the noids open. Then it drop down to the 6.5 rang (I assume I'm driving lol)

I'll be honest with you. I don't run a safety switch. But I like to live dangerously lol

If you can run your boat at WOT and have someone watch the fuel psi gauge on the solenoid, and see what it says while it's open (activated) without the nitrous it can be a workaround for no flow gauge

I hope that makes sense.

As always. Start with the smaller shot you can, back 2 degrees out for every 50 hp then work your way up from there.

« **Reply #11 on:** February 13, 2016, 05:59:57 PM »

Nice little video on flowing fuel pressure on the nitrous fuel system.

« **Reply #12 on:** February 13, 2016, 06:30:17 PM »

Quote from: 78Southwind on February 13, 2016, 05:59:57 PM

Nice little video on flowing fuel pressure on the nitrous fuel system.

yup thats exactly how it works.

« **Reply #13 on:** February 13, 2016, 08:07:03 PM »

Since it seems like it is a lot easier to flow the nitrous fuel pressure system with an electric fuel pump, can I use a similar 140 GPH electric pump instead of using my mechanical 140 GPH? I just want to use the electric for testing.

« **Reply #14 on:** February 13, 2016, 08:09:04 PM »

Quote from: 78Southwind on February 13, 2016, 08:07:03 PM

Since it seems like it is a lot easier to flow the nitrous fuel pressure system with an electric fuel pump, can I use a similar 140 GPH electric pump instead of using my mechanical 140 GPH? I just want to use the electric for testing.

Ehhhh idk if that would be right. Every pump is different hence why we need to flow them

I really don't know

« **Reply #15 on:** February 14, 2016, 07:29:17 PM »

Cool video, but I don't like how he used that guage. The bigger guage you get when you actually buy a flow guage set is cool because you can see the small amounts of fuel psi better. Here is my guage that Speed Tech Nitrous sent me.

« **Reply #16 on:** February 14, 2016, 07:30:14 PM »

I call my flow guage ( Flavor Flave) lol

« **Reply #17 on:** February 18, 2016, 07:21:20 PM »

So Clay Smith got back to me and said that the mechanical pump will handle the fuel demand. Now, I just need to find out a safe way to flow the pump and wait for more parts. I was thinking about plumbing the fuel system similar to this. However, I like the look of the brackets that come off of the manifold to hold the fuel regulators.

« **Reply #18 on:** February 18, 2016, 07:57:10 PM »

Quote from: 78Southwind on February 18, 2016, 07:21:20 PM

So Clay Smith got back to me and said that the mechanical pump will handle the fuel demand. Now, I just need to find out a safe way to flow the pump and wait for more parts. I was thinking about plumbing the fuel system similar to this. However, I like the look of the brackets that come off of the manifold to hold the fuel regulators.

(Attachment Link)

if your pump will feed it that will work.

Sent from my iPhone using SoCal Jet Boats

« **Reply #19 on:** February 19, 2016, 01:39:39 PM »

« **Reply #20 on:** February 19, 2016, 02:34:48 PM »

You are not flowing the N2O system. You are flowing the fuel system to verify that there is enough volume produced by the pump to maintain sufficient pressure in the system.

Remember that pressure is the result of resistance to flow. Once the flow increases, the pressure drops.

« **Reply #21 on:** February 19, 2016, 02:50:47 PM »

Quote from: Flusher on February 19, 2016, 02:34:48 PM

You are not flowing the N2O system. You are flowing the fuel system to verify that there is enough volume produced by the pump to maintain sufficient pressure in the system.

Remember that pressure is the result of resistance to flow. Once the flow increases, the pressure drops.

« **Reply #22 on:** February 19, 2016, 02:55:49 PM »

There another N2O thread recently, that I can't find right now.

It stated using a specific size jet for flowing a fogger and another for a plate. That jet is to restrict the flow to simulate the demand of the N2O system so that you are measuring FLOWING pressure as opposed to STATIC pressure (which will be higher).

« **Reply #23 on:** February 19, 2016, 02:56:53 PM »

Quote from: 78Southwind on February 19, 2016, 02:50:47 PM

I am not sure if I wasn't clear in my previous post but that is what I am saying. The tech said there was no need to flow it when using their kit. Maybe that's why they recommend squared jets.

I believe he saying that there is no need to flow the Edelbrock system

« **Reply #24 on:** February 19, 2016, 02:57:57 PM »

But that is down stream of the pump and regulators

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