Got my car Dynoed today... Graphs, Kinda scary A/F

[BuffMUSTANG]

Here are the pics of the graphs from today... The first run (red line) was on the engine... The second run (Green line) the bottle pressure was at 1000psi and then FPSS was cutting the nitrous in and out at first, it was almost like a surge... The third run (Blue line) the bottle pressure was at 900 and this was the best run.... It was a lot smoother...
Run 1: 248.19HP 288.83TQ
Run 2: 336.78HP 449.43TQ
Run 3: 342.80HP 455.50TQ

The dyno guys said that my fuel pump was not keeping up with the Nitrous and that i need to get a better fuel pump and that i should put the next size up fuel jet in to be safe. The A/f worried me... 13.7 is not good...

After everything i would say i'm satisfied with the numbers but i would like the Nitrous HP numbers up a little bit...

I have the videos if someone wants to host them...

What does everyone else think??????

 

[ADRENLN]

id say the bigger fuel pump wil lhelp, just like with a blower

 

[YtnGT]

This is pretty standard with a wet nitrous system...

What kind of system do you have?

Most people will give you the standard response of " dude you need a larger pump" and back it up with no information. Most of the time they don't even have a power adder...

I refuse to take BS advice, so here is what I have found. When the nitrous system engages it causes a drop in fuel pessure and it takes the computer time to ramp up the duty cycle to the fuel pumps. You can see this at 3.3K rpms your a/f goes slightly lean. Then the PID control loop catches up and the a/f settles down nicely. It is not a fuel pump issue or you would be lean at higher rpms. You are lean down low (right after N2O engagement).

I am experiencing the same issue with my NX 100 shot. I go lean right after N2O engagement and then then it richens up. It is a computer controlled fuel pressure issue and a larger pump will not help. Be carefull with some of the advice you will receive around here...

 

[YtnGT]

FYI
You know your fuel pressure is dropping (oscillating) because the FPSS is cutign in and out. I had to set my FPSS @ 30-32psi to keep it from opening up at the beginning of a N2o run.

 

[onesticker]

Wouldn't a multiple program chip work? Have a setting just for the nitrous to help with the a/f? I'm not sure, I don't have much experience with spray.

 

[YtnGT]

Do a little reading...

Fuel Pump Thread

Fuel Pump II Thread

 

[2002BLGT]

need to adjust or get a new FPSS , looks like its not engaging till 3400 RPMS , do you have a rpm window switch on the car ? what kind of system is it ????

 

[YtnGT]

need to adjust or get a new FPSS , looks like its not engaging till 3400 RPMS , do you have a rpm window switch on the car ? what kind of system is it ????

The FPSS engages and disengages based off of fuel pressure. I had to lower my FPSS set point to 32psi (give or take a pound or two) to keep from dropping the solenoids out. What is going on here is when the fuel solenoid opens extra fuel is required to supply the N2O system. The fuel pressure momentatily drops, the fuel pressure sensor sends this info to the computer, and the computer increases the duty cycle (voltage) to the pumps. So what you are left with is a dip in fuel pressure. That should explain the FPSS issue and your lean issue.

 

[BuffMUSTANG]

need to adjust or get a new FPSS , looks like its not engaging till 3400 RPMS , do you have a rpm window switch on the car ? what kind of system is it ????

I have the NX kit PN:20922 with the GenX-2 upgrade kit as well as a MSD window switch set at 3000 and off at 5800, going to change it to 6000 though...

 

[SRMobile]

Man those are some insane torque numbers

 

[2002BLGT]

put in a focus pump just incase and ditch the FPSS or set it lower

 

[Darkhorse845]

Man those are some insane torque numbers

Nice torque numbers!

 

[mrvax]

Nice numbers, YtnGT seems to know his chit. I have heard that our 19lb fuel injectors are only good to about 300rwhp because they begin to run at 100% duty cycle. Maybe an upgrade in FI may help too.

 

[BuffMUSTANG]

http://209.245.59.135/Gimme/7522448...5-84B2-C87182480844/0.865405/3/Dyno#1---NAmpg

http://209.245.59.166/Gimme/7522448...-C87182480844/0.737285/3/Dyno#2---1000psi.mpg

http://209.245.59.141/Gimme/7522448...2-C87182480844/0.966961/3/Dyno#3---900psi.mpg

 

[TeriiK]

honestly you're AF numbers are fine. dont go up a jet size, you'll F it all up and the car wont hit at all. aside from the hiccup at 3400 you're way in the safe zone, and even at the bump you're below 14/1 AF. you might want to do some more bottle runs, sometimes on a wet kit if its your first pull, there is still a delay in the fuel hitting the fogger, that delay can be more pronounced if you have purge on the NO2 side. all in all, you're doing fine.

 

[mrpositraction]

If you look at the dyno graph, how it is really wavey, this means that the engine is starving for something, I would at least look into the fuel pressure and see what it is doing while under spray, the A/F ratio given isn't too lean. In fact it looks fine. But what kind of A/F ratio was he using, if he was using the kind that they stick the sensor up the tailpipes, they are known not to be as accurate as taking the data directly from the computer. I would do some more test before you make any drastic changes, just keep your foot out of it until then. I know, it will be hard.

 

[BuffMUSTANG]

http://ezshare.de/files-en/178944/Dyno_1--NA.mpg.html
http://ezshare.de/files-en/178994/Dyno_2--1000psi.mpg.html
http://ezshare.de/files-en/179055/Dyno_3--900psi.mpg.html


Here ya go... These should work... Just wait about 25secs after the page pops up... Then you can DL the vids...