Need some nitrous advise and expertise

[stoutner]

O.K. I had a little free time today at work and am trying to figure out the easist way to "bump" up my nitrous shot on my Apex.

I have the Boondocker nitrous with the fuel control module. This module allows me to adjust fuel through the injectors. It is my understanding that the stock injectors are big enough to flow enough fuel for at least an 80 Hp shot. My controller will adjust that high....so, if the injectors will handle it, I will be o.k. with fuel.

For those not familiar with boondocker, they give you 2 "manifolds" which spray into the air box. Each manifold gets either a 3, 4, or 5 hole nozzle. Each hole sprays enough nitrous for about 5HP. I currently run two of the 5 hole nozzles for 50 HP shot.

Instead of buying 2 more manifolds, tee fittings, and hose, I want to just drill out my 4 hole nozzles (that I am currently not using) to an orifice size that will allow for a 10HP spray per hole. Once drilled out, I will replace the factory nozzles with these.

Attached is a spread sheet with my calculations. Please look it over and see what you think. Is my math/engineering solid? If not, please comment. If so, please comment. Thanks !!!

 

[Blown14psi]

Looks good but I wouldn't rely on any dry system to support the fuel for such a big hit your asking for trouble.

I was told by N.O.S. and NX that the reason they provide an extra fuel pump in their kits is that the stock fuel pump won't support more than about 30HP more than stock. These guys have been around the longest and I Trust their knowledge more than anyone else.

 

[stoutner]

I am o.k. with the fuel. I had mine dyno tested with the 50 HP nozzles and had plenty of fuel. I tuned it in to have a BSFC of .50 to .53 throughout the RPM range while on the NOS. My stock BSFC when not on the button ranged between .44 and .50 throughout the range. So, On the NOS I am running a little richer than that to be "safe". I was able to pretty much flood the motor out using the controller even when on the NOS. So, I'm pretty sure I have a lot of fuel adjustment left.

I also checked a dyno report of a guy running a Boondocker Turbo that uses the stock injectors and the Boondocker fuel controller. On his dyno, his stock injectors/fuel pump were just about at the limit when he hit 235 HP....and that was on a turbo.

I would think I can run nitrous a leaner than turbo to make the same HP???

The good thing is....if I can't get the fuel, I'll just take the nozzles back out and throw them away. It takes about 5 minutes to change the nozzles.

Thanks for looking at that. I just hope my "math" on orifice sizing is correct.

 

[yamahajunkie]

tune with race fuel first, sound good.

 

[Blown14psi]

I am o.k. with the fuel. I had mine dyno tested with the 50 HP nozzles and had plenty of fuel.

O.K. you may be able to get enough fuel, but most automotive guys will tell you that 50hp is max for a dry system even on a car.

It's not that the fuel system won't provide the fuel it's the LEAN SPIKE that the motor see's before the injectors react and supply the additional fuel.

It's the LEAN SPIKE that causes DETO and burns down your engine. At 80HP you'll only have to DETO a couple of times to damage your engine and I don't think the race fuel will help but you could try

 

[stoutner]

Yes, definately going to tune with race fuel first.

As far as the injectors reacting too slowly...ummm, I've never heard of that. Thanks for the input. That would be a problem. I did notice when dyno tuning, I did have a slight (1/4 second) "lag" when hitting the button. I actually thought this was the injectors flooding the engine before the nitrous travelled through the solenoid, tubes, and airbox. I never notice this "lag" anymore when riding. The "lag" did show up on the dyno graph. I looked at the dyno report and don't see any fuel drop but, what you are talking about is probably a split second drop that wouldn't show up. Am I correct?

Attached is the report.

 

[ejcamaro]

It could be that boondocker has engineered the kit to put the extra fuel in a split second before the nitrous is activated. I'm not familiar with boonies kits, but that wouldn't surprize me that they would have that figured in for safety, hence, the slight lag (which is a good thing).

The holtzman kit has the fuel jets closer to the motor than the nitrous jets, therefore the fuel always gets there first.

 

[Blown14psi]

The only way to tell if the lag is from an overly rich condition or over lean condition is to check it with an exhaust sniffer and datalog the AF ratio throughout the powerband and when you spray the N2O.

You can also see it on a wideband but you'll have to be quick to see it.

It may work fine but with that much nitrous flow you don't have much room for error.

 

[stoutner]

Hey guys. Thanks for the input. I'm going to give it a shot....heck, I have over 4500 miles on it. Time to put it to the test

 

[efiguy]

The lag is definitely from the fuel getting into the engine before the nitrous. Depending on where the nozzles are mounted, the more nitrous and fuel you add, the worse this will get. There is new programming available for the Boondocker box that allows you to set a delay to overcome this problem (just talk to me, Dave, and I'll get you set up).

Your calculations based on increasing the surface area to deliver more nitrous is a good place to start. There are some other factors such as friction losses from the nitrous contacting the surfaces of each hole (more and smaller holes generally make this worse), and possible pressure drop inside the poly lines and the manifold itself due to the higher flow, but these are probably small factors until you get to around 90hp. Just be prepared to do some clutch work, use race gas, and keep a close eye on your plugs (gap them down to about .020 and go one size colder - might make it a little more difficult to warm up in the cold). Detonation will break/melt the electrodes off plugs and break ring lands. Good luck!

 

[stoutner]

The lag is definitely from the fuel getting into the engine before the nitrous. Depending on where the nozzles are mounted, the more nitrous and fuel you add, the worse this will get. There is new programming available for the Boondocker box that allows you to set a delay to overcome this problem (just talk to me, Dave, and I'll get you set up).

Your calculations based on increasing the surface area to deliver more nitrous is a good place to start. There are some other factors such as friction losses from the nitrous contacting the surfaces of each hole (more and smaller holes generally make this worse), and possible pressure drop inside the poly lines and the manifold itself due to the higher flow, but these are probably small factors until you get to around 90hp. Just be prepared to do some clutch work, use race gas, and keep a close eye on your plugs (gap them down to about .020 and go one size colder - might make it a little more difficult to warm up in the cold). Detonation will break/melt the electrodes off plugs and break ring lands. Good luck!

Dave,

I did think about friction and poly line sizing. I plan on going 80 HP but maybe 90....not more. I already run a colder plug. I will full race gas when using that size shot. My nozzles are mounted in the sides of the air box. Do you work for Boondocker? I do have one other question for you if you do....

Is the controller programmed in a "linear" fashion? In other words...if my fuel setting is at 30 does changing it to 60 double the amount of fuel...and 90 triple it? I have tuned mine in at 30hp (35 fuel), 40hp (45 fuel), and 50hp (55 fuel) nozzles and fuel settings are 10 higher for each 10 HP. For the 40HP nozzles, my fuel setting is 45. So, if I run 80HP nozzles, would my fuel setting be about 85-90? Also, that delay problem...what would I have to do? Send it in for reprogramming?

Thanks in advance for your help.

 

[efiguy]

Yes, I work for Boondocker. The amount of EXTRA fuel delivered at 60 will be double the EXTRA fuel at 30. The correlation of the fuel number to nitrous amount (10 fuel for 10 hp N2O) is sort of a coincidence, but gives a good starting point. Be careful your fuel pressure doesn't drop at the higher numbers (this may require even more fuel numbers). There's new programming that has a lot of new features. If you bought your box in the past year, I can upgrade it for free.

 

[stoutner]

Yes, I work for Boondocker. The amount of EXTRA fuel delivered at 60 will be double the EXTRA fuel at 30. The correlation of the fuel number to nitrous amount (10 fuel for 10 hp N2O) is sort of a coincidence, but gives a good starting point. Be careful your fuel pressure doesn't drop at the higher numbers (this may require even more fuel numbers). There's new programming that has a lot of new features. If you bought your box in the past year, I can upgrade it for free.

Dave, I did buy it last Fall. I will call you later this week.

Thanks a lot!!!

Wayne S.

 

[stoutner]

Yes, I work for Boondocker. The amount of EXTRA fuel delivered at 60 will be double the EXTRA fuel at 30. The correlation of the fuel number to nitrous amount (10 fuel for 10 hp N2O) is sort of a coincidence, but gives a good starting point. Be careful your fuel pressure doesn't drop at the higher numbers (this may require even more fuel numbers). There's new programming that has a lot of new features. If you bought your box in the past year, I can upgrade it for free.

Dave,

Your phone screener got me I left a message for you. If you didn't get it, check your PM. I will send you a PM.

Thanks, Wayne Stoutner