Dyno experts please help!
Thread Starter
Melting Slicks
Joined: Sep 2000
Posts: 3,150
Likes: 1
From: Carlsbad, CA CA
Dyno experts please help!
I just figured out that there is definitely a fuel delivery problem in the steel blue.
The first dyno chart is made on the motor and you can definitely tell that the fuel flow is not at a constant rate. The unsmoothness in the power curve could also be felt through the seat of the pants.
However, in the second dyno chart with the nitrous and extra fuel provided by the fuel jets smoothes out the power and the difference could definitely be felt as well. All the fuel and ignition components on the car is brand new. Could this be because the fuel line is too small? Any information is greatly appreciated!
The first dyno chart is made on the motor and you can definitely tell that the fuel flow is not at a constant rate. The unsmoothness in the power curve could also be felt through the seat of the pants.
However, in the second dyno chart with the nitrous and extra fuel provided by the fuel jets smoothes out the power and the difference could definitely be felt as well. All the fuel and ignition components on the car is brand new. Could this be because the fuel line is too small? Any information is greatly appreciated!
Team Owner
Joined: Apr 2000
Posts: 27,818
Likes: 8
From: CT
Re: Dyno experts please help! (zelement)
I'd have to start with which fuel pump are you using? Is it sufficient enough for BOTH motor and NOS? Secondly, how big are the injectors? What fuel pressure? You get the general idea. Timing obviously is very crucial.
Point out some details and I am sure others will chime in. Just for reference...on my 383, I am using a Vortec GM Truck pump, stock lines etc..Accel adj regulator(40 psi idle- I forget what it goes to when you're on it..but it goes up and stays up...be sure yours does too) and 26 pound injectors.
Sorry I can't help you more.
Point out some details and I am sure others will chime in. Just for reference...on my 383, I am using a Vortec GM Truck pump, stock lines etc..Accel adj regulator(40 psi idle- I forget what it goes to when you're on it..but it goes up and stays up...be sure yours does too) and 26 pound injectors.
Sorry I can't help you more.
Burning Brakes
Joined: Nov 2001
Posts: 1,241
Likes: 9
From: Houston TX
Re: Dyno experts please help! (zelement)
nothing wrong with those curves. if you're "feeling" surging power when driving, whatever it is doesn't show on those graphs.
n/a, your a/f ratio is varying between 12.0 and 13.0. it would be better if it stayed more constant, but nothing bad.
your nitrous runs are mega rich. i guess better safe than sorry, although if it's really running that rich, i'd be concerned about lack of ring lubrication, and contamination of gas in oil.
n/a, your a/f ratio is varying between 12.0 and 13.0. it would be better if it stayed more constant, but nothing bad.
your nitrous runs are mega rich. i guess better safe than sorry, although if it's really running that rich, i'd be concerned about lack of ring lubrication, and contamination of gas in oil.
Melting Slicks
Joined: Aug 2001
Posts: 2,047
Likes: 0
Re: Dyno experts please help! (zelement)
It is possible to plot other data along either the X or Y axis against RPM. If the shop that you're doing this at has all the data acquisition capabilities, I would hook up the fuel pressure sending unit and also wideband O2. If the fuel pressure falls off as you climb in RPM, you know what the deal is. I'm betting you're on the right track already. Another $150 or so will tell the tale. Put it on the dyno again. It's worth spending that $$$ rather than a new motor or experimenting with parts! It's inexpensive insurance!
Thread Starter
Melting Slicks
Joined: Sep 2000
Posts: 3,150
Likes: 1
From: Carlsbad, CA CA
Re: Dyno experts please help! (MSR)
I am running brand new fuel filter, FMS 24# injectors with a TPIS 550 HP in-tank pump, and the Fuel pressure is set at 40lbs with vaccum line disconnected. I don't have a fuel guage so I can't tell if the pressure raises when I run it on the dyno.
MSR,
That particular run with the nitrous turned out to be super super rich because we guessed the fuel jets, but made sure it would be rich if anything, it was not a suggested jetting by Nitrous Express. With a NX suggested 100 shot it pulled 441.1 hp 418 tq and A/F was 12.1 to 1. So, if I had the right jet for 150 shot the A/F mixture should be the same.
There is for sure something wrong with the motor runs because all three motor passes on the dyno had erractic spikes in the curves like the one shown, and all three nitrous passes were smooth like the one shown.
Even the guy that ran the car on the dyno said the power delivery wasn't smooth at all!
MSR,
That particular run with the nitrous turned out to be super super rich because we guessed the fuel jets, but made sure it would be rich if anything, it was not a suggested jetting by Nitrous Express. With a NX suggested 100 shot it pulled 441.1 hp 418 tq and A/F was 12.1 to 1. So, if I had the right jet for 150 shot the A/F mixture should be the same.
There is for sure something wrong with the motor runs because all three motor passes on the dyno had erractic spikes in the curves like the one shown, and all three nitrous passes were smooth like the one shown.
Even the guy that ran the car on the dyno said the power delivery wasn't smooth at all!
