We have all heard it, the nitrous beats the fuel that causes the lean spike. Or the nitrous beats the fuel and caused the car to caugh....

WILL HOW much time difference is there...

On a direct port kick, AS MOTORSPORTS plugged data logging sensors into the Nitrous Express rails. This is to see the time it takes the rail to fill and pressurize.

SO we have a SBC, DIRECT PORT, with RAILS. system PSI is 14 fuel 1050 on the nitrous. LOts and lots of space to fill up right.

Here it is!!!!!! we see FUEL pressure in the rail before nitrous pressure.. Several dyno pulls and we got .02-.05 seconds from seeing fuel pressure to nitrous pressure.
The fuel beats the nitrous liquid to the nozzle.....
WHY
fuel is a liquid and can not be compressed... Nitrous, when the noid opens turns to a gaseous state. A solid can travel faster... Also you have a vacuum pulling the fuel and the nitrous.

Now gaseous nitrous might beat the fuel to the nozzle there is no way to tell that by this test.. and real in a gaseous state who cares..

The 2 fpss switches got test on this car and NO way would it work, the car went way rich before the nitrous got there to clean it out...

NOW put this into perspective.. DIRECT port kit, single nozzle, lots of space to fill, little space to fill. The nitrous is not the direct cause of the lean spikes people see on the dyno.

I am willing to bet that the lean spikes are caused by the nitrous slowing the air flow down or destubing it just enough to freak the signal at the MAF or Carb. to slow that fuel flow down for a moment....

But world may never know...

"Thank you AS MOTORSPORTS for conducting this test on the race car."


Ricky

 

That's some good information. Thanks for posting.

 

No problemo!

 

Good info for sure. I wonder how we could test this on a standard wet kit. It seems it would be less of a problem than filling up the rails on direct port. I do know the lean spike is a reality though. You may be on to something, a dry hit will also have a lean spike and no fuel rail or line to fill, however, the maf does read a n2o shot and richens accordingly (maybe late?), thinking there is more air, so air theroy is? Something is causing both system to have an intitial lean spike, hmmm...
Robert

 

I wonder will his A/F ratio graph show a lean spike with a (non fuel injected) carburated set up.

 

Do we know for sure that this lean spike is really a lean spike at all??? The wideband sensor could somehow be affected.... Nice info! FPSS setup wouldnt work but....I told yall. lol

 

the dual FPSS did work no lean spike but really really really rich at first.
Ricky

 

Yep. Too much delay, and even if the fuel did arrive after the nitrous which we now know doesnt occur, the deadband on a FPSS is too wide to be useful.

 

Interesting to say the least. Not sure on other setups...but one thing to note is the setup, pics please? Since we are a EFI board, I am assuming this was on Fuel Injected setup and hopefully more than 14psi, inferring that this is using a dedicated fuel cell for the nitrous, which would also be inferred from it being a race car as you state.
Now, run the fuel tapped off the injectors rails and try it again, I bet you a coke-cola that there will be a major lean fuel spike as the fuel is drawn out of the inj. rails and through the fuel noid taking the path of least resistance!

note #2, I'm on a roll, one single wet kit, larger shots, the drivers bank WILL show lean ona wideband opposed to normal / rich on passenger side from wet kit pulling fuel as the DP does, but only from the Drviers side of inj rail.

Just muy $.02

 

I thought you where going to tell me, the chicken or the egg??? WTF. lol

 

Interesting for sure...
Ricky

 

The egg came first I thought everone knew that. But that is not the real question.
Ricky

 

or was it the chicken

 

nope the egg. Watch a special on TV about a year ago.. The Dinosaur laid the egg that became the chicken..
So which was first the dinosaur or the egg... The world may never know..
hows your car doing.... Need some more nitrous.
Ricky

 

Interesting,

frirst of all, Thanks AS Motorsports for sharing that info.

a few questions though. Were each of the 4 nozzles measured or just one of them. If so, which one?

Also, was fuel in the rail, or was it dry? I assume that if you don't spray for a while (maybe minutes, hours or days, not sure) the fuel after the solenoid drips out or evaporates out of the nozzle. But right after a pull fuel stays in the rails and lines, kinda like putting your thumb over a staw full of water. So I could see a big difference in time if there was already fuel after the solenoid, vs. no fuel.

Lastly, how was the test conducted? How did you measure time so accuratly?

 

Interesting,


frirst of all, Thanks AS Motorsports for sharing that info.

a few questions though. Were each of the 4 nozzles measured or just one of them. If so, which one?

Also, was fuel in the rail, or was it dry? I assume that if you don't spray for a while (maybe minutes, hours or days, not sure) the fuel after the solenoid drips out or evaporates out of the nozzle. But right after a pull fuel stays in the rails and lines, kinda like putting your thumb over a staw full of water. So I could see a big difference in time if there was already fuel after the solenoid, vs. no fuel.

Lastly, how was the test conducted? How did you measure time so accuratly?

 

Thats all cool, but you would see the same initial pressure drop on a gauge coming off the rail tap....Doesnt happen I've tested this several times.....edit. Also dry kits see the same initial wideband spike from what I hear.

 

Cool test...thanks. I was thinking maybe a better pressure switch, or some adjustable check valves with a high cracking pressure on the far end of the nitrous rails to relieve the nitrous gas pressure until it built up to XXX psi then closed forcing the hopefully liquid nitrous into the nozzle.....

But screw it...I finally ordered my MAX II. I want to play around with the settings running each noid from a different stage with different offsets at specific RPMs in RPM based mode. Seems like the way to go especially now that you have the multiple ramp points in the graph. Or possibly offset the fuel noid with the TPS settings to kick on a split second prior

Ricky...I know you where saying something about alternating noids with the MAX II with the dual drivers having an effect on this? Have you messed around with it any more?

 

Hey Vinny, the rails would be dry as soon as you left off the button.. Since there is 4 holes in the rail from the nozzles air can come up one and drain all fuel out of the system pretty quickly... AS Motorsports notice a rich conditioin for a bit after the pull and then cleaned out.. Also I have test a direct port on a Saturn and saw the same thing.. After the pull the rails was dry. The straw is the absolute with the single nozzle thou, only one way for air to get in an as long as the noid is not perfectly flat with the nozzle you get that vaccuum effect..
Test was done having datalogging sensor in the rails, and the data logger was the RPM version Data Jr. I beleive...
http://www.rpmperf.com
You can pick them up from NX.....That data logger is bad ***, AS Motorsports (Tommy) has used several different data loggers and think this on is the best. Easiest to down load, read, understand...
Ricky

 

The multi points not yet.. The water/injection and 341 stand alone fuel and ignition systems out the door.. THen the multi points are coming....

Now to the fuel offset. WHY not needed as you mention earlier...BUT IF U want to here is how you can.... MAke sure you down load the latest version.. In the config part it allows you to choose how the noids will be fired...TOgether lots of amp draw, so One set at a time, kind of spike and load saving. Put into the together mode... Then set stage 1 ramps once done copy stage 2 ramps from stage one.. Now both are the same untouched its like having 1 stage thats it... Modifi the stage that you want to delay ei nitrous... Then the fuel will fire first and then the nitrous... Talk to FJO the agreed, all bets are off if you do this, since they them selves have never tested in that mode...

Let me know the results, we are adding more and more stuff to that unit...
Did you get the special on that unit.
Ricky