: dyno #s



stbtt
07-12-07, 11:55 AM
i made a new intake for the car and put back on the dyno the best i could get out the car stock was 215 hp with just a cone at the end of the maf the best i could get was 224 hp now with the new setup i got a best of 231 hp

best of what i had to what i have now
http://i149.photobucket.com/albums/s77/stbtt/t.jpg
here is the nitrous with the old intake didnt have any n2o for the runs with the new setup
http://i149.photobucket.com/albums/s77/stbtt/tt.jpg
and the negative hp run
http://i149.photobucket.com/albums/s77/stbtt/1.jpg

eldorado1
07-12-07, 01:15 PM
very substantial gains... what specifically were the differences?

stbtt
07-12-07, 01:27 PM
it is a 4 in pipe going down under the facory box and moved the maf down there as well i was getting high iat and was running lean so i put it down there to cool it down and richen up the air fuel it was getting 14.5-14.9 now it is down to 13.2-13.5 it is the diff. in air/fuel that help in the gain

eldorado1
07-12-07, 01:52 PM
You were getting 14.5:1 at wide open throttle???? :eek:

stbtt
07-12-07, 02:34 PM
yes i was getting that at wot
here are some pics of the new setup i made
http://i149.photobucket.com/albums/s77/stbtt/DSC01701.jpg
http://i149.photobucket.com/albums/s77/stbtt/DSC01702.jpg
http://i149.photobucket.com/albums/s77/stbtt/DSC01703.jpg
http://i149.photobucket.com/albums/s77/stbtt/DSC01704.jpg
http://i149.photobucket.com/albums/s77/stbtt/DSC01705.jpg

eldorado1
07-12-07, 02:44 PM
Was this a "tail pipe" o2 sensor? Do you have cats? You can't trust readings made after cats. It will read lean. Interesting that it changed so much after relocating the IAT though.

stbtt
07-12-07, 02:54 PM
the readings are before the cat i wielded a bung in for tunning the nitrous but when i went to tune the n2o i left the jets at home so that is what i started with and staying with untill someone can make a program for me to edit the pcm 100 hp at the wheels is good for now air/fuel on the n2o is nice and safe at 11.8

eldorado1
07-12-07, 03:02 PM
wow, that is dangerously lean. 13.5 is still pretty lean. Something has to be wrong.... Have you scanned for codes?

AJxtcman
07-12-07, 03:22 PM
wow, that is dangerously lean. 13.5 is still pretty lean. Something has to be wrong.... Have you scanned for codes?

What?
I was under the impression some cars came out of the factory running 17 to 1. Yes they ran like crap, but the emissions readings were good.

AJxtcman
07-12-07, 04:10 PM
WRAF?:bigroll:

eldorado1
07-12-07, 05:41 PM
What?
I was under the impression some cars came out of the factory running 17 to 1. Yes they ran like crap, but the emissions readings were good.


Factory cars are running 10-12:1. They do this to keep the pistons from melting.

Are you sending out tuned PCMs running that lean? Liability would be a b@#$^ if you had to buy people new engines.

AJxtcman
07-12-07, 05:47 PM
Factory cars are running 10-12:1. They do this to keep the pistons from melting.

Are you sending out tuned PCMs running that lean? Liability would be a b@#$^ if you had to buy people new engines.

10 to 1 would kill an o2 sensor.
WRAF reading??
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After this morning I had two sets of keys cut. One is stuck in my igntion in the on position. I will post the information you are lacking later

AJxtcman
07-12-07, 06:38 PM
I think that Dyno tuning should be done with a WRAF.
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Some Background
The "conventional" O2 sensor in use since 1978 can tell the engine control system only that the exhaust is either too rich or too lean. It’s called a switching sensor because it makes a sharp voltage transition when the air/fuel mixture varies a tiny amount either side of ideal (14.7:1 for a gasoline engine). (fig. 5)

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Refer to figure 5, Typical Switching-Style O2 Sensor Signal.
A. O2 Voltage (mV)
B. Time (s)
C. Rich-Lean
D. Lean-Rich

The engine controller responds to a rich signal from the O2 sensor by leaning the mixture, and responds to a lean signal by richening the mixture.

Even more precise fuel control would be possible if the O2 sensor could detect the exact deviation of the exhaust stream, lean or rich. The new wide-range air/fuel sensor can do this.

Wide-Range Air-Fuel Sensor (WRAF)
The wide-range air-fuel sensor, or WRAF sensor, discussed in this article will be used in the 4.6L LH2 engine in the 2004 Cadillac XLR and SRX. This sensor may also be referred to as a lambda sensor or wide-band sensor.

The WRAF sensor has been used in the past on select models of GM vehicles with the 3.0L L81 engine, first in the 1999-2001 Cadillac Catera, then in the 2000-2004 Saturn LS.

TIP: Throughout service information, the wide-range air-fuel sensor is referred to using the standard terminology of heated oxygen sensor or HO2S; in this article we will refer to it as the WRAF sensor.

Advantages of the WRAF
A typical V6 engine operating at 2500 rpm will produce approximately 62 cylinder pulses per second per cylinder bank. Refer to the graph in figure 5, which displays the voltage of a switching-style oxygen sensor. During one rich-to-lean and lean-to-rich transition of the oxygen sensor signal (1/2 second), there will be approximately 30 cylinder pulses.

Each cycle or switch is the average air-fuel ratio of several cylinders.
With a switching-style sensor, the engine controller will merely continue to adjust fuel trim, rich or lean, until it sees a signal swing in the opposite direction. The process then reverses and continues transitioning rich-to-lean and lean-to-rich. This explains the constant cycling or switching of the switching-style sensor.

So, the first advantage of the WRAF sensor is that it can detect the exact deviation from 14.7:1, rich or lean, and allow the engine controller to precisely adjust the air-fuel ratio to the desired amount.

TIP: Ideal combustion occurs with an air-fuel ratio of 14.7:1, also referred to a stoichiometric.

Most switching-style oxygen sensors operate within a range of 0 to 1000 millivolts, and as a result will not provide an accurate reading when the air-fuel ratio exceeds approximately 14.6:1 when rich or 14.8:1 when lean.

The WRAF sensor (fig. 6) can provide an accurate signal when the air-fuel ratio is as lean as 16:1 or as rich as 11:1, allowing the engine controller to continuously adjust fuel trim throughout this wide range of air-fuel ratios. So, a second advantage of the WRAF sensor is its ability to provide an accurate signal while operating in an air-fuel ratio, or lambda state, other than stoichiometric .

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Refer to figure 6, WRAF Sensor.
A. Trimming Resistor
B. Resistor Cover
C. Sensor

WRAF Wiring and Circuits
Refer to figure 7, WRAF Sensor Cutaway.
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The WRAF sensor has six wires (circuits), divided among three functions.

Reference Voltage -- The engine controller provides a fixed signal voltage to the WRAF sensor on two circuits. These circuits are called the reference voltage circuit (D) and the low reference circuit (E) from the reference air duct (P).

Pump Current -- There are two circuits called the input pump current (F) and output pump current (G). They provide an electromotive force needed for the movement of oxygen ions inside the sensor.

Heater (N) -- As with a switching-style sensor, there are heater voltage supply (L) and heater low control (K) circuits. They are similar in operation to most switching-style sensors.

Each sensor contains a trimming resistor (M) that is integral to the sensor connector. This trimming resistor is used during sensor manufacturing to calibrate each sensor to the desired performance specifications.

Operation
Here is what happens as exhaust flows past the sensor. Refer to the WRAF sensor cutaway (fig. 7):
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1. As the exhaust stream (A) passes the WRAF sensor, a sample of the exhaust gases enters the exhaust gas sample tube (B) and moves through the diffusion gap (C).

2. When the air-fuel ratio of the sampled exhaust gas changes, there is a corresponding change to the voltage potential between the reference voltage circuit (D) and the low reference circuit (E).

3. When the voltage on these circuits changes, the engine controller changes the amount of voltage on the input pump current circuit (F) and the output pump current circuit (G).

4. As the voltage on the input and output pump current circuits changes, oxygen ions move into or out of the pumping cell (H) through the porous layer (J). This brings the voltage potential between the reference voltage and low reference circuits back to a desired value.

5. By monitoring the required voltage and current level change on the input pump current and output pump current circuits, the engine controller can determine what the air-fuel ratio is at that moment.

6. The engine controller can then determine exactly how much the air-fuel ratio needs to be adjusted to maintain the desired voltage potential and thus the desired air-fuel ratio.

The WRAF sensor is able to determine the exact amount of air-fuel ratio change required for the upcoming cylinder pulses. This is different from a switching-style sensor, which has a much larger estimating error of the air-fuel ratio change.

On a low level, there is closed-loop operation between the engine controller and the WRAF sensor pumping circuits, low reference circuit, and reference voltage circuit.

On a high level, there is closed-loop operation between the exhaust sampling of the WRAF sensor and total fuel trim adjustment. The latter is similar to the most traditional closed-loop fuel systems.

How to Interpret WRAF Sensor Data on the Tech 2
TIP: Even though the engine controller and the WRAF sensor use various voltage levels during operation, the signal value displayed on the Tech 2 is a lambda value, NOT a voltage value.

The variable name “lambda” refers to the deviation above or below stoichiometric, or 14.7:1 air-fuel ratio. A lambda value of 1.000 is equivalent to a perfect stoichiometric ratio of 14.7:1. Depending on vehicle platform, the lambda value can be as low as 0.750 or as high as 3.999. A low lambda value represents a rich exhaust sample, and a high lambda value represents a lean exhaust sample.
The lambda value can be used to calculate the exact air-fuel ratio.

For example, a lambda value of 1.025 on the scan tool indicates that the system is operating lean. To find out exactly how lean, multiply 1.025 by 14.7. This gives the result of approximately 15.07:1. Conversely, a lambda value of 0.975 indicates the system is operating rich. Multiply 0.975 x 14.7 = 14.33:1. This gives you an idea of how the controller is able to determine the exact desired air-fuel ratio.

The Meaning of Extreme Lambda Values
How can a lambda value of 0.750 or 3.999 be meaningful? Multiply a lambda value of 3.999 x 14.7 = 58.79:1. This is clearly not an air-fuel ratio that any engine could operate under during cruise or acceleration.

Extreme lambda values are a result of the limits of the controller hardware and software. When a vehicle enters a fuel cut-off state during deceleration, the lambda value may move to a very high number (infinity) because the controller software and hardware are operating the pumping circuits at their maximum correction state to offset the extremely lean air-fuel ratio that is occurring. The controller software will not display infinity but will instead display a large number. Depending on the controller manufacturer, these maximum limits may be as low as 0.750 during a very rich condition, or as high as 3.999 during a very lean condition.

Typical WRAF Sensor Lambda Values (fig. 8)
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Acceleration and Cruise -- The lambda value stays fairly flat, close to 1.000, during the moderate to heavy acceleration and during cruise (A). This is because the sensor and the engine controller are in their own closed-loop operation and the lambda value only “drifts” above or below 1.000 as the engine controller makes its fuel trim adjustments. This closed-loop operation between the engine controller and the WRAF sensor is an instantaneous reaction to voltage deviations between the reference voltage circuit and low reference circuit and the resulting oxygen ion exchange via the pumping circuits.
Power Enrichment -- The lambda value moves lower when power enrichment is active (B).

Deceleration -- During deceleration, the lambda value moves to 1.989. This is because the engine controller has commanded a deceleration fuel cut-off state and, as a result, the exhaust stream is extremely lean (C). Notice how the engine controller will regulate the closing of the throttle; the throttle plate must be less than five percent open before the lambda value will finally move to 1.989. On this particular vehicle, 1.989 is the limiting value of the hardware and software.

Diagnosing a WRAF Sensor
Here are a few points to remember when diagnosing a WRAF sensor:

- With the sensor disconnected and the ignition on, the voltage level measured on the input pump current circuit or the output pump current circuit, on the engine harness side, is very low and should be measured using the DMM millivolts scaling.

- In addition to the input and output pump current circuits, with the sensor disconnected and the ignition on, there will be a voltage present on the reference voltage circuit, low reference circuit, and possibly the heater low control circuit. The applicable DTC tables, when necessary, will provide the exact voltage values. Of course, there will be battery voltage present on the heater ignition voltage supply circuit.

- The voltage that may be present on the heater low control circuit is a diagnostic voltage produced by the engine controller. This voltage is used by the engine controller to discriminate between a heater circuit open, short to ground, or short to voltage condition. Depending on platform, the diagnostic voltage may or may not be present.

- Remember this when performing voltage measurements on the engine harness side. When a circuit fault is present, it may cause voltage level changes on the input pump current, output pump current, reference voltage or low reference circuits. So, you must not assume that because the voltage of the first circuit you measured is not within the correct range it is the problem circuit!

- As with any heated oxygen sensor, no circuit repairs should be attempted to the sensor harness.

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http://216.182.211.32/techlink/images/issues/may03/TLMay03e.html#story10

eldorado1
07-12-07, 07:31 PM
All dyno tuning should be done with a wideband. And yes, it really should run 10:1 after 15 or so seconds in power enrichment. This is done to cool the piston crown. There's no need to post wideband cutaways, I know what they are and how they work.

http://sdsefi.com/techtunesds.htm


Best power is usually obtained with an AFR of between 11.8 and 13.0 on most engines.

Usually people aim for 12.6:1.

Highline Cady
07-12-07, 08:03 PM
Stbtt,
I saw the nitrous. I assume you have a STS looking at the way you are running the air intake? Are you running wet or dry? What kinda extra pop, 50hp 75hp 100hp? What does it run on the bottle? Any good or bad news since using nitrous, and could you recomend a kit or part number? I have some left over nitrous parts off an old TA I used to have that I sprayed, and lately have been thinking about putting the spray on the Cady.

Really any information, good or bad, would be appreciated, maybe I could make a sleeper to. Thanx.

AJxtcman
07-12-07, 08:09 PM
I was under the impression you cool the pistons with oil.
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If you can't tell what the A/F ratio is you better be rich. Since an O2 sensor gets lost at 14 to 1 it is better to calculate A/F and be rich. If you can tell what the A/F at 13 or even 12 to 1 using a WRAF you can use the power that may have been lost.
How much power is lost at 12 to 1 over stoichiometric at WOT?
How much is lost at 13 to 1 at WOT over stoichiometric?
If you go Lean how much is lost?
Rich is bad, but lean is not good at all. If you go rich you will hurt performance slightly, but Lean can cause engine damage, Global warming, Converter failure, High High HC's.
Lean = High HC's and Low CO.
Rich = Low HC's and High CO.
Lean = raw gas in the tail pipe!:eek:

eldorado1
07-12-07, 08:15 PM
4.6L northstars don't have piston squirters. :bigroll:

How much power is lost at 12:1 over stoichiometric? LOL! You mean gained? Did you miss the part where I said maximum POWER is at 12.6:1?

AJxtcman
07-13-07, 07:01 AM
4.6L northstars don't have piston squirters. :bigroll:

How much power is lost at 12:1 over stoichiometric? LOL! You mean gained? Did you miss the part where I said maximum POWER is at 12.6:1?

How is the A/F ratio measured at 12.6 to 1?
What is the method being used to measure the A/F to clarify that question?
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I checked and no squirters yet for the 08 northstars. You know it has to happen soon. I think they have them in just about every engine except just a few.

msta293412
07-13-07, 08:52 AM
Hey tell us more about your NOS set up.

eldorado1
07-13-07, 09:09 AM
How is the A/F ratio measured at 12.6 to 1?
What is the method being used to measure the A/F to clarify that question?


When tuning? Or when in a vehicle?

You use a wideband when you're tuning.

In the vehicle, it's not measured. Narrowband o2 sensors can't measure anything but 14.7:1. However it can estimate where 12.6:1 is, and it's usually not too far off. GM usually aims for pig rich though (11-12:1).

stbtt
07-13-07, 10:36 AM
the nitrous setup is a wet kit 2 stage with a msd rpm window switch nothing fancy just parts i had laying aroud from other cars i had the jets are 42 nitrous 28 fuel on both stages it has given 100hp at the wheels

i have had no problems with anything on the car after the n2o install other than when the bottle is empty and i cant have any fun playing with some of the f-body cars and a few of the vetts around here

stbtt
07-13-07, 10:49 AM
each car is going to run its best at diff air/fuel every motor is diff evan if it is the same kind of motor from what i have leard though years of tuning is what i just stated the ideal a/f is anywere 12.5-13.2 you can make power with a leaner mixture but ect can get hot quick i will set a car up to run i little rich like 12.7 on the bottom end and lean it out to about 13.2 on the top end i never like to go any leaner than that

Highline Cady
07-13-07, 12:55 PM
Did you have to modify any fuel mixtures for the nitrous? Or are all these minor modifications just to run optimal NA, did you have to retard the timing? I guese what I'm asking is was the nitrous a true bolt on, or did you have to start changing stuff just so you could run the NOS? I'd rarely be using a nitrous setup if I did this to my tank, but I love the idea of messing around with kids in their f-bodies from time to time. Especially on the freeway. Thanks for the info and the help, you might just convince me to grab the NOS bottle in my garage, get it filled, buy a few minor parts, bolt it in, and go looking for someone to surprize!!!

stbtt
07-13-07, 01:28 PM
no mods just put it on and went sprayed with the datalog the ecm is pulling alot of timing out then ramping back up that is why the bottom lower rpm power smoothly ramps up instead of just coming on hard

AJxtcman
07-13-07, 01:37 PM
each car is going to run its best at diff air/fuel every motor is diff evan if it is the same kind of motor from what i have leard though years of tuning is what i just stated the ideal a/f is anywere 12.5-13.2 you can make power with a leaner mixture but ect can get hot quick i will set a car up to run i little rich like 12.7 on the bottom end and lean it out to about 13.2 on the top end i never like to go any leaner than that

In five years or less you will wonder why 12.7 was ever ok.
I am not going into the reason on your thread. You do need power enrichment. In the near future you will learn about the accurate AFR measurement being used in engine R&D and some cars.
I am not saying that you are wrong.
If you add NO2 it changes the AFR. You would need more fuel by weight ratio.
I believe AFR is relative to the weight. 14 grams to 1 gram.

stbtt
07-14-07, 10:14 AM
In five years or less you will wonder why 12.7 was ever ok.
I am not going into the reason on your thread. You do need power enrichment. In the near future you will learn about the accurate AFR measurement being used in engine R&D and some cars.
I am not saying that you are wrong.
If you add NO2 it changes the AFR. You would need more fuel by weight ratio.
I believe AFR is relative to the weight. 14 grams to 1 gram.

i have no idea what you are tring to say power inrichment is when the pcm will see wot and will use diff fuel tables. in most cars that are put out now have power inrichment delay set as high as 5000 rpm so they dont even get into pe tables untill that rpm is past or an amount of time has past. 12.7 is ok because it will alow a good burn of fuel for bottom end torque and lean it out alittle on top for hp. in most gm cars that i have got in the pcm a/f demand for wot can be as rich as 11-1 this is the first time i have seen a car from gm have a flat a/f that was around 13 most cars are set up from the factory to run around 13.5 on the bottom then go rich starting at about 4000 rpm.
i am not useing n2o to cange a/f you can tune nitrous 2 ways you can add n2o to lean it out or pull fuel out. afr can be looked at in any form wiegh,parts or what ever 14 to 1 just means you have 14 parts air to 1 part fuel.
like i said i dont know what your trying to say

eldorado1
07-14-07, 02:50 PM
One of the powertrain engineers that worked on the northstar has this to say:


Engine developers run very cold spark plugs to avoid the risk of getting into pre-ignition during engine mapping of air/fuel and spark advance, Production engine calibration requires that we have much hotter spark plugs for cold startability and fouling resistance. To avoid pre-ignition we then compensate by making sure the fuel/air calibration is rich enough to keep the spark plugs cool at high loads and at high temperatures, so that they don't induce pre-ignition.

Consider the Northstar engine. If you do a full throttle 0-60 blast, the engine will likely run up to 6000 RPM at a 11.5:1 or 12:1 air fuel ratio. But under sustained load, at about 20 seconds, that air fuel ratio is richened up by the PCM to about 10:1. That is done to keep the spark plugs cool, as well as the piston crowns cool. That richness is necessary if you are running under continuous WOT load. A slight penalty in horsepower and fuel economy is the result.

It's a fantastic read if you haven't read it:

http://www.streetrodstuff.com/Articles/Engine/Detonation/Page_7.php

AJxtcman
07-14-07, 03:20 PM
Guess what the AFR is on this. It is just an ECOTEC
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eldorado1
07-14-07, 03:57 PM
AJ: Northstars are NOT direct injection. It does not apply.

AJxtcman
07-14-07, 09:28 PM
It is the ability to measure the AFR and have no driveability issues

msta293412
07-17-07, 01:08 PM
AJ, I am having trouble finding a spare PCM. The one I had was bad.....I just want to tell you my info. 2001 sts, vin# 1g6kys54941u224750. Do you have a fairly aggresive program(without bugs) for my vehicle. By the way I have intake and exhaust work done. Also do you have any suggestions on getting a PCM or getting a tuned one from you without any downtime? Any response would be greatly appreciated.

msta293412
07-17-07, 01:09 PM
Woops, I should of posted that on the other thread.