Dyno Nitrous Results...very disappointed

[01 RT SNAKE]

I took the car to get dyno'd today and to get the air/fuel readings. I'm running a NX Wet Kit. The FJO mini computer is set to start at 2600 rpm (30%) and 100% at 3000 rpm. It is 100% all the way to 5700 rpm.

My air/fuel was absolutely terrible. Below 10:1 on the chart. I followed NX's jetting recommendations.

100 shot 35 N20 / 18 Fuel
150 shot 41 N20 / 22 Fuel
200 shot 52 N20 / 33 Fuel

I called NX and they agreed that the car was running way too rich and was hurting the numbers. The tech recommended I up the N20 jet and leave the fuel jet alone. On my last run I ran a 41 N20 and a 18 Fuel. It gave the best air/fuel readings but the numbers were still low. I gained a whopping 56.5 peak HP.

Here's the graphs...

This is my pre-nitrous dyno done last year at a different dyno shop.

My three runs were:

421.91 hp / 451.16 tq
429.75 hp / 456.73 tq
428.65 hp / 459.19 tq

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This is my baseline today. I'm running a NGK plug one step colder than stock. My numbers were down just a bit (about 3-10 peak hp torque pretty much stayed the same). I'm guessing it's just a dyno variance.

418.2 hp / 457.8 tq

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Here's the 100 shot....

463.8 hp / 536.9 tq

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Here's the 150 shot...

468.5 hp / 563.7 tq

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Here's the 200 shot...

466.1 hp / 574.5 tq

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Here's the 41 N20 and 18 Fuel jets

474.7 hp / 568.0 tq

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Notice, the air/fuel is much better on this run, however, it's still not close to the approximate 125 HP shot.

My bottle pressure was around 925-950 psi on all the runs. NX said it should be 1000-1050 psi. I still don't think the bottle pressure being slightly low should have resulted in a 150 hp discrepency on the 200 shot.

Anyone care to diagnose this and tell me what's wrong?

My mods are K&N's, tubes and a Corsa exhaust.

Mike
2001 RT/10

 

[RedEnuf93]

LOW bottle pressure.
Keep it around 1050-1100, HUGE difference.
Do you have a bottle heater?

Try again with that.

 

[v10kingsnake]

You also need to watch that the ultra rich condition didn't foul any plugs. The good new is you are rich which is much safer than being lean. Keep us posted.

 

[01 RT SNAKE]

Would being low 50-100 psi on the bottle pressure cause these pathetically low numbers? I checked the plugs, they're fine.

Yes, I have a bottle heater.

When they weighed the bottle after the runs, it had 3.5 lbs of nitrous in it (10lb bottle). This would include about 4 street blasts approximately 3-4 seconds each on the 100 shot and the 4 nitrous runs today.

Mike

 

[mntngts99]

I would get six passes on a ten pound bottle. I used a 42 nos / 25 fuel and made 607 rwhp and 700+ rwtq at 1100 psi on the bottle at 11.4 AFR.

 

[plumcrazy]

yes those low bottle pressures can make a HUGE difference.

get heaters and bring it up to 1050psi.

my car ALWAYS ran super rich. it takes time to find the right jets and tuning. but at least you know you're safe

 

[BigCarrot]

A 10lb bottle lasts no time at all on a Viper. Fill it up, get the pressure to 1100-1200, check your plugs (and make sure they are gapped properly) and see what it does. Dual bottles would be worth while.

 

[Jack B]

A couple of insights. You can make as much hp at 950 as you can at 1050, it is just a matter of jetting it correctly. In other words, at lower pressure it just take a larger NOS jet.

The problem you are having is more than likely that you are spraying gas, not liquid. Watch for too many 90's or more importantly look for any increase in size of the feed line. As an example iy you go up in fitting size as you move forward, it will turn to gas. In addition, if you have it too close to a heat source, it will become a gas. It can also happen at a solenoid or in a filter.

 

[RTTTTed]

A friend of mine once told me that his Nitrous kit made NO power so I installed it into my car. I had to turn the fuel pressure down so far to get any power from the bottle that it was obvious why his kit wouldn't make much power - No nitrous to help burn the fuel that went into the engine. The fuel makes the hp, not the Nitrous.

Since I had installed the kit into my car we knew the problem wasn't the car or the instal - it had to be the kit, so I told him to return it. It turned out that the feed line inside the bottle was too long and had kinked so not enough Nitrous would get out of the bottle so the mixture would run way too fat - no power. Once the tube was shortened the kit worked fine.

I'd suggest that you first check the line for kinks, then take the solenoid apart and check the filter. If that doesn't find the problem disconnect the fuel solenoid and see how far the solenoid opens with the computer controlling it. If you don't find the problem, return it as disfunctional. You obviously aren't getting the correct amount of Nitrous for the amount of fuel you SHOULD be injecting.

Since you had to run too small of jets for the amount of fuel it takes to make the hp for the Gas jet, it means that you're not getting enough Nitrous. The fuel makes the hp and the Nitrous is the "air" for the mixture. Less fuel = less hp.

Ted

 

[viper spray]

My Gen I made more power than that with the old NOS 5180 system...........

 

[Russ M]

The NX kit was very poorly jetted anywhere above 100hp, and even that was extremely rich. You need to up the bottle pressure to get a good base to work with, 1050 is a good PSI, then adjust your jets from there.

On the 100 shot you should be making 500-510 rwhp, if you keep recomended jetting and only 520 or so on the 150 and 550 or so on the 200. So what you need to do is change the fuel jets on the 150 and 200.

You need to get a hold of Alan on this forum, he had the setup you have. And did a bunch of dyno testing to validate the numbers. So getting jetting off him will be ideal in your situation.

 

[FATHERFORD]

NX sets up there kits super rich for a reason.. It's not an error.. Up the bottle pressure some with a full bottle and try again. Are you sure your FJO controller isnt staying at 30%?

 

[ACELLR8]

Something is wrong with your setup. Running 900 PSI of bottle pressure should make a lot more power than that.

You did not pick up any HP when you upped the shots. I know it sounds dumb but I would ensure you have a full bottle. Also, is your bottle positioned properly so the pickup tube in the bottle is in the bottom.

Also, I see Fatherford mentioned about your FJO Controller possibly being stuck at 30%, that would seem about right that you are only getting %30 of the HP of a certain jet. I would suggest taking that out of the system and trying it just using the full throttle switch.

 

[viperrt96]

Got a question about your settings with the FJO

Are you "RPM Based"? (next to type) there is a option to be
'Timed- Based"

You should use "RPM Based" if you are you will see three rpm window settings

RPM trigger , RPM end and RPM cutoff

The trigger is obvious but the "RPM end" can be confusing. If you have the "RPM end" set at 5700 like the "cutoff" the nitrous wont go 100% until 5700.

You should have it set something like 3200 "trigger" and 4200 "end" and 5700 "cutoff"

It will ramp from 3200 30% (start or trigger) up to 4200 end (where it will hit 100%) and then stay 100% up to 5700

The graph you see below is just the ramp from "trigger" to "end" not "cutoff"

 

[01 RT SNAKE]

Here is my bottle setup...

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This is the delivery...

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I have since added a Fuel Pressure Safety Switch and a Fuel Pressure Gauge before the gas solenoid since taking this pic.

My FJO is set up to trigger at 2600
RPM end at 5700
RPM cutoff at 5750
It is RPM based and ramped from 2600 rpm @ 30%
2763 rpm @ 50%
2926 rpm @ 75%
3089 rpm @ 100%
3089-5700 rpm @ 100%
I didn't pic these weird numbers, the program does it when you choose rpm based as opposed to a time based trigger.

Viperrt96, my graph shows that the nitrous is 100% from 3089-5700?? You're saying that the window should be smaller on the graph?

Here's my last question. If the bottle only had ~3.5 lbs in it when we were done testing, would say 4-5 lbs have been sufficient enough to still make close to advertised numbers at 925-950 psi?

Oh, and each run was purged prior to testing.

 

[plumcrazy]

do you have a lot of breaks in the line ? how about angles ?

did you check to make sure the solenoids were working maybe ?

 

[viperrt96]

My FJO is set up to trigger at 2600
RPM end at 5700
RPM cutoff at 5750
It is RPM based and ramped from 2600 rpm @ 30%
2763 rpm @ 50%
2926 rpm @ 75%
3089 rpm @ 100%
3089-5700 rpm @ 100%
I didn't pic these weird numbers, the program does it when you choose rpm based as opposed to a time based trigger.

Viperrt96, my graph shows that the nitrous is 100% from 3089-5700?? You're saying that the window should be smaller on the graph?

Here's my last question. If the bottle only had ~3.5 lbs in it when we were done testing, would say 4-5 lbs have been sufficient enough to still make close to advertised numbers at 925-950 psi?

Oh, and each run was purged prior to testing.

If you have the RPM end @5700 it is not at 100% @ 3089. I had this same problem with mine in the beginning. Change your RPM End to something like 4200 and you will notice the graph will not change. Just the bar. your NOS will then be 100% at 4200 up to 5750

 

[RedEnuf93]

Make sure you have a FULL bottle, not 4 lbs or 3....

 

[99 R/T 10]

Make sure you have a FULL bottle, not 4 lbs or 3....

Bingo! Pressure and a full bottle are vitial to getting a good run

 

[PowerKraus]

You've received some great advice. Let me offer some pointers on a 'quick and dirty' field test. Take the necessary precautions to not deliver any fuel while doing the following, and do not get yourself some freezer burn either. Before you go pulling selenoids apart, do a quick test for us.

Bypass the FJO controller, get full 'hot' to the nitrous 'noid.
Remove and cap off the fuel to the fuel selenoid (safety measure).
Grab your aligator clips/wire and establish a 'hot wire' connection to the nitrous 'noid. Keep track of this, as you'll need to jump this in a moment.
Unscrew the nozzles, keep the nitrous and pill inplace.
Secure the nozzle in a fashion so the anticipated plum shoots up/away from you and the car.
Check bottle pressure, and 'hit' the nitrous 'noid........IF working properly, you should see a nice 6' plum come out of the nozzle.

If no results, try again with the nozzle and pill removed (to rule out some type of clog in the nozzle)...a plum should shoot out the nozzle feed line.

If another no go, or lazy 'squit' from the nitrous line...swap out the bottle with a known working unit and try again. If no go again, then remove the nitrous feed line and see if the freaking bottle, when turned on, is even delivering nos to the 'noid.

Anyway, you get my drift.....kind of like plumbing.....confirm you have delivery, then start at the other end and work backward toward the source. hope it works out. the list above assumes some general knowledge about the workings of the system, so if you feel a little puckered, then by all means, do not attempt without the assistance of one who knows. I've had great success with NX and TNT kits, this sounds like a real simple problem to fix, e.g. bad bottle feed as mentioned above.


...oh, and if you get a great plum....double check the fuel delivery & look at your FJO set-up and all electrical connections
Rob

 

[IEATVETS]

Fill the bottles then report back.

When I had Nitrous on my 94 RT and the bottles dropped below 4#'s, I had a huge drop in power.

 

[01 RT SNAKE]

Thanks for all the great advice guys. I'll try and get this done this week.

Another guy from a different board mentioned that it looks like I'm getting nitrous delivery because of the torque numbers. Should the torque on a 100 shot be more than 536? My torque on the 41/18 shot was 568. Should I be in the mid to high 600's?

Mike

 

[viperrt96]

I mocked up on my FJO program to the numbers you gave and I got the following

Your settings

RPM Trigger = 2600
RPM End = 5700
RPM Cutoff =5750

Here are the results

2600=30%
2763=34%
2926=37%
3089=41%
3253=45%
3416=48%
3579=52%
3742=58%
3908=59%
4068=62%
4232=67%
4395=71%
4558=74%
4721=78%
4884=82%
5047=85%
5211=89%
5374=93%
5537=96%
5700=100%

Like I said RPM end can be confusing. I do like progressive controllers. I like them most of all because you can bring the NOS on easy rather than all on at once giving it less shock. That said you do want your NOS on 100% by the time you hit your power curve.

So if you keep all of your settings the same change just your RPM end to something like 4200 and you'll see the numbers change to the following

2600=30%
2684=34%
2768=37%
2853=41%
2937=45%
3021=48%
3105=52%
3189=56%
3274=59%
3358=63%
3442=67%
3526=71%
3611=74%
3695=78%
3779=82%
3863=85%
3947=89%
4032=93%
4116=96%
4200=100%
then you'll stay 100% all the way up to your cutoff of 5750

 

[RedEnuf93]

Why would you have 100% at 4200RPM? Just my 2 worthless cents, I would have it much earlier than 4200. With 4200 you are not going to be a long time at 100% powerband, maybe a second or so? You go through 4 gears in 1/4 mile, that means that the 100% hits only 3 times maybe 3 sec alltogether...?

Its not like 150 shot is a lot anyway... I hit mine with 150, 200, 225 and 300 shot, all without progressive.

 

[viperrt96]

Why would you have 100% at 4200RPM? Just my 2 worthless cents, I would have it much earlier than 4200. With 4200 you are not going to be a long time at 100% powerband, maybe a second or so? You go through 4 gears in 1/4 mile, that means that the 100% hits only 3 times maybe 3 sec alltogether...?

Its not like 150 shot is a lot anyway... I hit mine with 150, 200, 225 and 300 shot, all without progressive.

I was just making an example. That's close to my tune for the street. You can also say Progresssive controllers are NOS for dummies. A progressive controller will shut off my NOS if I miss a shift. I don't want it on 100% before let's say 3000rpm. If you flow a Big shot of NOS at a low rpm you can easily have detonation, Worse yet you can easily bend connecting rods . I think common sense would tell you any engine can handle more NOS when it's in proportion to engine RPM. The motor is going to handle safely twice the NOS at 4500 than at 3000rpm. Only a controller can do that for you.

And no a 150 shot is nothing to a V10. Any NOS manufacturer will tell you as a general rule of thumb for safe NOS use is 20hp for every cylinder. So a 4 cyl can easily handle a 80 shot. A V8 can easy handle a 160 shot. V10's can easily handle a 200 shot

 

[FATHERFORD]

Why would you have 100% at 4200RPM? Just my 2 worthless cents, I would have it much earlier than 4200. With 4200 you are not going to be a long time at 100% powerband, maybe a second or so? You go through 4 gears in 1/4 mile, that means that the 100% hits only 3 times maybe 3 sec alltogether...?

Its not like 150 shot is a lot anyway... I hit mine with 150, 200, 225 and 300 shot, all without progressive.

Are you using an external fuel cell for that 300 pill? I plan on running an external with 104 unleaded octane or the likes for a 250-300 pill for my car.

 

[Jack B]

Are you using an external fuel cell for that 300 pill? I plan on running an external with 104 unleaded octane or the likes for a 250-300 pill for my car.

I am running a two stage progressive 350 shot with a 255 lph pump and a voltage booster and it runs fat thru the quarter. As a matter of fact I've had it up to a 400 shot with the same set-up.

 

[kwkshift]

What's wrong with 100% from 3000-5600 rpm?

 

[viperrt96]

What's wrong with 100% from 3000-5600 rpm?

If you flow a Big shot of NOS at a low rpm you can easily have detonation, Worse yet you can easily bend connecting rods . I think common sense would tell you any engine can handle more NOS when it's in proportion to engine RPM. The motor is going to handle safely twice the NOS at 4500 than at 3000rpm

With a big shot I think 100% at low RPM's (3000rpm) could mean disaster. That's the whole point of having a progressive controller. Bring it on in proportion to the power (rpm) range.

 

[Jack B]

What's wrong with 100% from 3000-5600 rpm?

how about breaking the tires loose at 100 mph when you are running 14 psi in the slicks.