Put my car on the Dyno at Mid America, results inside with pic of the sheet
09-22-2003, 11:18 PM
#1
Drifting
Thread Starter
Put my car on the Dyno at Mid America, results inside with pic of the sheet
The first run was the strongest at 230.4 HP and 325.2 torque
Second run was 230.6 HP and 321.3 torque
Third run was 229.3 HP and 320.1 torque
Is it normal for the torque to drop off a little on each run? The numbers didnt vary by much.
Torque was over 300 foot pounds by 2800 RPM, 325 foot pounds by 3000 RPM and stayed over 300 till 4000 RPM.
The operator said my A/F ratio was from 12.8 to 13.2. What does that mean?
This is rear wheel power. How does that relate to the factory rating of 240 HP and 330 pound feet? Is the car actually losing power from stock?
It was a blast at the fest. We had a good time. I spent most of my day at the dyno.
Second run was 230.6 HP and 321.3 torque
Third run was 229.3 HP and 320.1 torque
Is it normal for the torque to drop off a little on each run? The numbers didnt vary by much.
Torque was over 300 foot pounds by 2800 RPM, 325 foot pounds by 3000 RPM and stayed over 300 till 4000 RPM.
The operator said my A/F ratio was from 12.8 to 13.2. What does that mean?
This is rear wheel power. How does that relate to the factory rating of 240 HP and 330 pound feet? Is the car actually losing power from stock?
It was a blast at the fest. We had a good time. I spent most of my day at the dyno.
09-23-2003, 12:36 AM
#3
Le Mans Master
Re: Put my car on the Dyno at Mid America, results inside with pic of the sheet (Paul G)
If I were to guess why the numbers fell slightly after each run I would say it was heat buildup after the previous run. I would probably guess you had let the car sit and cool prior to it being put on the dyno for the first run.
Good Numbers... :cheers:
Good Numbers... :cheers:
09-23-2003, 07:08 AM
#5
Drifting
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Re: Put my car on the Dyno at Mid America, results inside with pic of the sheet (Paul G)
The first run was the strongest at 230.4 HP and 325.2 torque
Second run was 230.6 HP and 321.3 torque
Third run was 229.3 HP and 320.1 torque
Is it normal for the torque to drop off a little on each run? The numbers didnt vary by much.
The hotter the engine the less power output.
Torque was over 300 foot pounds by 2800 RPM, 325 foot pounds by 3000 RPM and stayed over 300 till 4000 RPM.
That's good midrange RPM torque for street driving.
The operator said my A/F ratio was from 12.8 to 13.2. What does that mean?
That means 12.8 parts air, 1 part fuel. optimum ratio is 14 to 1. So it was a little rich, but at full throttle the computer will give the engine as much fuel as the fuel pump can give and the injectors will pass. Economy goes out the window.
This is rear wheel power. How does that relate to the factory rating of 240 HP and 330 pound feet? Is the car actually losing power from stock?
To find HP at the flywheel, you have to factor that 18% is lost in the drivetrain with auto trans. (15% for manual trans.).
It was a blast at the fest. We had a good time. I spent most of my day at the dyno.
It is very addictive... :thumbs:
Second run was 230.6 HP and 321.3 torque
Third run was 229.3 HP and 320.1 torque
Is it normal for the torque to drop off a little on each run? The numbers didnt vary by much.
The hotter the engine the less power output.
Torque was over 300 foot pounds by 2800 RPM, 325 foot pounds by 3000 RPM and stayed over 300 till 4000 RPM.
That's good midrange RPM torque for street driving.
The operator said my A/F ratio was from 12.8 to 13.2. What does that mean?
That means 12.8 parts air, 1 part fuel. optimum ratio is 14 to 1. So it was a little rich, but at full throttle the computer will give the engine as much fuel as the fuel pump can give and the injectors will pass. Economy goes out the window.
This is rear wheel power. How does that relate to the factory rating of 240 HP and 330 pound feet? Is the car actually losing power from stock?
To find HP at the flywheel, you have to factor that 18% is lost in the drivetrain with auto trans. (15% for manual trans.).
It was a blast at the fest. We had a good time. I spent most of my day at the dyno.
It is very addictive... :thumbs:
[Modified by Q1KSLVR, 7:17 AM 9/23/2003]
09-23-2003, 07:25 AM
#6
Drifting
Thread Starter
Re: Put my car on the Dyno at Mid America, results inside with pic of the sheet (Q1KSLVR)
If it is a little rich at WOT would an AFPR be helpfull to lower the fuel pressure? Or would that hurt performance?
09-23-2003, 08:33 AM
#7
Re: Put my car on the Dyno at Mid America, results inside with pic of the sheet (Q1KSLVR)
I agree with everything but this
There is a very important distinction that needs to be made here.
The ideal air to fuel ratio is 14.7:1 under part throttle and cruising because this burns all of the fuel, thus gives you the least harmful emissions. For maximum power though 14.7:1 is VERY lean and can potentially be dangerous.
For peak power most cars like an air fuel ratio of around between 12 & 13. Every car is a little different so you would really need to play with the tuning to nail it down for sure, but I'd say you're pretty close. My personal experience has been that 12.8:1 is damn near perfect for most cars. You might find one or two more horsepower by moving it up or down a tad, but it's really not worth spending any money on. It's running so good right now why risk screwing it up? Remember they say if it ain't broke, don't fix it.
Also, believe me the comptuer doesn't max the pulse width on the injectors at WOT, there is PLENTY of room for adjustment in the computer program. If the computer set the injectors for maximum pulse width the car would be running so rich it would barely run at all. The computer does go to "power enrichment" mode when you go wide open throttle. This basically means that it knows you are WOT, it knows you want the power so fuel economy be damned. It goes to a set of values for fuel and timing so as to provide peak power, which happens to be right where his is running. :cheers:
One more thing. The car has no way of knowing what your fuel pressure it is running. When you are crusing at part throttle it tries to maintain a 14.7:1 air fuel ratio by either adding or subracting fuel. It calculates your instantaneous MPG and average based on how much fuel it thinks you are flowing. If you raise or lower the fuel pressure you will screw up these values. The computer knows how much the injectors are supposed to flow. Now if you raise the fuel pressure you will flow more fuel, the computer will have to cut back on the pulse width. All the computer knows is that it is having to cut back on the injector open time to get at the right A/F ratio. It doesn't know why, so it assumes it is less fuel. As such all your MPG readouts will get screwed up.
So while an adjustable fuel pressure regulator might let you tune at WOT, it will only screw up what the computer knows at part throttle. Now call me crazy, but I want all that fancy stuff on the dash to be as accurate as possible. What's the point of having all those neat toys if they don't work? To me nothing yells ghetto like having a bunch of gauges that don't work, or display the wrong values all the time. That's also not to mention that the computer will constantly be having to adjust the long term fuel trims to compensate for the injectors, which looks really crappy on a scan tool. It also narrows the cars range of what it can adjust for.
So what can we do? Get a real computer tune. If your driveability is perfect and you just need a little more fuel up top you can play with the power enrichment vs RPM tables and add a little bit more fuel. Suddenly rather than having to guess the computer still knows exactly what is going on at cruise, yet adds more fuel at WOT.
I've got all the adjustment room that I could possibly need to make my car run richer or leaner, just by playing with the computer. I'm pushing 379 horsepower to the ground, on stock injectors, on stock fuel pressure. IMHO the adjustable fuel pressure regulator is WAY over rated.
[Modified by Nathan Plemons, 7:44 AM 9/23/2003]
[Modified by Nathan Plemons, 7:45 AM 9/23/2003]
That means 12.8 parts air, 1 part fuel. optimum ratio is 14 to 1. So it was a little rich, but at full throttle the computer will give the engine as much fuel as the fuel pump can give and the injectors will pass. Economy goes out the window.
The ideal air to fuel ratio is 14.7:1 under part throttle and cruising because this burns all of the fuel, thus gives you the least harmful emissions. For maximum power though 14.7:1 is VERY lean and can potentially be dangerous.
For peak power most cars like an air fuel ratio of around between 12 & 13. Every car is a little different so you would really need to play with the tuning to nail it down for sure, but I'd say you're pretty close. My personal experience has been that 12.8:1 is damn near perfect for most cars. You might find one or two more horsepower by moving it up or down a tad, but it's really not worth spending any money on. It's running so good right now why risk screwing it up? Remember they say if it ain't broke, don't fix it.
Also, believe me the comptuer doesn't max the pulse width on the injectors at WOT, there is PLENTY of room for adjustment in the computer program. If the computer set the injectors for maximum pulse width the car would be running so rich it would barely run at all. The computer does go to "power enrichment" mode when you go wide open throttle. This basically means that it knows you are WOT, it knows you want the power so fuel economy be damned. It goes to a set of values for fuel and timing so as to provide peak power, which happens to be right where his is running. :cheers:
One more thing. The car has no way of knowing what your fuel pressure it is running. When you are crusing at part throttle it tries to maintain a 14.7:1 air fuel ratio by either adding or subracting fuel. It calculates your instantaneous MPG and average based on how much fuel it thinks you are flowing. If you raise or lower the fuel pressure you will screw up these values. The computer knows how much the injectors are supposed to flow. Now if you raise the fuel pressure you will flow more fuel, the computer will have to cut back on the pulse width. All the computer knows is that it is having to cut back on the injector open time to get at the right A/F ratio. It doesn't know why, so it assumes it is less fuel. As such all your MPG readouts will get screwed up.
So while an adjustable fuel pressure regulator might let you tune at WOT, it will only screw up what the computer knows at part throttle. Now call me crazy, but I want all that fancy stuff on the dash to be as accurate as possible. What's the point of having all those neat toys if they don't work? To me nothing yells ghetto like having a bunch of gauges that don't work, or display the wrong values all the time. That's also not to mention that the computer will constantly be having to adjust the long term fuel trims to compensate for the injectors, which looks really crappy on a scan tool. It also narrows the cars range of what it can adjust for.
So what can we do? Get a real computer tune. If your driveability is perfect and you just need a little more fuel up top you can play with the power enrichment vs RPM tables and add a little bit more fuel. Suddenly rather than having to guess the computer still knows exactly what is going on at cruise, yet adds more fuel at WOT.
I've got all the adjustment room that I could possibly need to make my car run richer or leaner, just by playing with the computer. I'm pushing 379 horsepower to the ground, on stock injectors, on stock fuel pressure. IMHO the adjustable fuel pressure regulator is WAY over rated.
[Modified by Nathan Plemons, 7:44 AM 9/23/2003]
[Modified by Nathan Plemons, 7:45 AM 9/23/2003]
09-23-2003, 08:52 AM
#8
Tech Contributor
Re: Put my car on the Dyno at Mid America, results inside with pic of the sheet (Nathan Plemons)
:iagree: with everything Nathan wrote above.
09-23-2003, 12:29 PM
#9
Le Mans Master
Re: Put my car on the Dyno at Mid America, results inside with pic of the sheet (96GS#007)
I did not read all the babble that Nathan wrote :jester but I am sure it was right on.
I would like to add (if he did not already) that the dyno has a lot less of a load than you would have on the street and that will account for a slightly richer reading on the wide band while on a dyno. 12.8 is almost ideal for LT1 motors NA, while closer to 12.2 is best while on the juice. Not sure about the L98 motors and their likings.
I would like to add (if he did not already) that the dyno has a lot less of a load than you would have on the street and that will account for a slightly richer reading on the wide band while on a dyno. 12.8 is almost ideal for LT1 motors NA, while closer to 12.2 is best while on the juice. Not sure about the L98 motors and their likings.
09-23-2003, 05:33 PM
#10
Drifting
Thread Starter
Re: Put my car on the Dyno at Mid America, results inside with pic of the sheet (Nathan Plemons)
Nathan you explained that very well. Thanks. I wish I had the stock chip that came with the car so the next time I see the dyno I could compare stock to the Hypertech.
If I were to install 1.6 rockers would they make much of a difference without doing anything at that time?
If I were to install 1.6 rockers would they make much of a difference without doing anything at that time?
09-23-2003, 06:16 PM
#11
Le Mans Master
Re: Put my car on the Dyno at Mid America, results inside with pic of the sheet (Paul G)
Nathan you explained that very well. Thanks. I wish I had the stock chip that came with the car so the next time I see the dyno I could compare stock to the Hypertech.
If I were to install 1.6 rockers would they make much of a difference without doing anything at that time?
If I were to install 1.6 rockers would they make much of a difference without doing anything at that time?
09-23-2003, 07:29 PM
#13
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Re: Put my car on the Dyno at Mid America, results inside with pic of the sheet (Paul G)
Looks good :thumbs:
take those numbers and add 17-18% and you get the crank rating
take those numbers and add 17-18% and you get the crank rating
