Well got off the phone with Nissan Engineer (coolinfo)
10-17-2002, 05:54 PM
#61
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Going to be a project that I'm undertaking.
Might end up w/ a kit that would allow the 2 ecus to play together. Seems the simpler and more flexable route, as opposed to reflashing the stock ecu.
Can't wait to hear what the tech guy has to say in answer to my questions.
BTW, great to hear your new transmission is doing well, InternetAbyss
Might end up w/ a kit that would allow the 2 ecus to play together. Seems the simpler and more flexable route, as opposed to reflashing the stock ecu.
Can't wait to hear what the tech guy has to say in answer to my questions.
BTW, great to hear your new transmission is doing well, InternetAbyss
Last edited by UnderPressure; 10-17-2002 at 05:57 PM.
10-17-2002, 06:05 PM
#63
Originally posted by UnderPressure
Going to be a project that I'm undertaking.
Might end up w/ a kit that would allow the 2 ecus to play together. Seems the simpler and more flexable route, as opposed to reflashing the stock ecu.
Going to be a project that I'm undertaking.
Might end up w/ a kit that would allow the 2 ecus to play together. Seems the simpler and more flexable route, as opposed to reflashing the stock ecu.
10-17-2002, 06:11 PM
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You have a great contact there. I understand what he was saying from my antiquated and somewhat faulty memory knowledge. You did a great job relaying it, you must have a photographic memory.
The emissions system or Emissions Control Module (ECM) is a closed loop feedback control system. It monitors the Oxygen sensors (yes plural for the Z, I have pictures) and adjusts the amount of fuel being delivered by the injectors to lean or richen the air/fuel mixture. Rich mixture means more power but also more polutants and the output voltage of the oxygen sensor changes. There are several types, still waiting on the Shop Manual to know what type is used on the Z. I am most familiar with the O2 sensor that toggles around .5 volts.
So, if you want to fool the ECM into thinking it's lean when it is actually rich then you have to fool the oxygen sensor. However, this type of oxygen sensor isn't easy to fool. Because it toggles around .5 Volts. By that I mean it never stays on .5 Volts. It does not have a linear ouput, it really jumps with a little change in O2. You can think of this type of sensor/feedback/control as a bang-bang control. One instant it is like .01 volts, the next instant it is over 1.0 volts as the ECM constantly adjusts more/less fuel. But what is amazing is how fast it does this and how little of a change in fuel (air/fuel mixture) it takes. So you can only fool it a little bit because eventually the computer has to bang back to lean and the only way it can do that is if it gets a sensor reading that requires a lean mixture to produce. So if you don't fool it correctly, the ECM probably detects a fault because it never goes lean or doesn't go lean often enough, probably lights the check engine soon lamp and goes into a default mode using pre-determined fuel amount settings in the ECU. IE default mode for a broke O2 sensor. Ok, so all you have to do is change the default fuel amounts so it will run rich once it reaches that mode and voila more power, but crappy emissions. Hence why you need to reprogram/rewire the ECM/ECU to change the default fuel settings for a broke O2 sensor mode.
If you bring in more air, then the ECM detects a lean mixture from the voltage on the O2 sensor and commands more fuel. Emissions are increased for lean mixtures too. Been a long time but I think rich fuel mixture yields increased hydrocarbons and lean yields more nitrogen oxides (NOX). Both types of emissions are what EPA is trying to reduce. So the ECU is always trying to control the Air/Fuel mixture to stoichiometric or about 14:1. At stoichiometric, you have the best situation for least hydrocarbons and least nitrogen oxides. So that is what the ECM does, it continuously reads the O2 sensor and adjusts the amount of fuel being delivered to achieve stoichiometric. Now it gets a little more complicated when you introduce acceleration/deacceleration and air temperature which means air mass and that is where the mass air flow sensor comes into play. The goal of the emissions system is to reduce emissions at all times under all conditions, cold engine, warm engine, high and low air temperatures , iddling, accelerating etc. As EPA reduces the allowable manufacturers emissions, the circuitry has to get more complicated to reduce emissions under all conditions.
That is why HP advantages by non-breathing improvement ad-ons won't add-on HP if the emissions are the same because the ECM is controlling the mixture. You have to fool the circuitry as well.
If you put on any type of intake (properly designed with info from Nissan that enhances breathing over the stock which is already pretty good) or Forced Induction which will need a bigger input pipe (plenum and MAF sensor) for best efficiency, you are moving more air into the engine and the ECM compensates by adding more fuel to avoid lean emissions. Which means more power. However as you force more air into the engine, you do two things. First you compress the air, which effectively raises the compression ratio and there is a limit (by design of engine internals - heads cranks bores etc). Secondly when you compress air it heats up. So you need an intercooler to cool the air after it is compressed but before it enters the engine to extend engine life and to get the yield out of the increased breathing (cooler air more HP). At the same time, the injectors and the computer that controls them (ECM/ECU) has to be able to provide the extra amount of fuel to maintain stoichiometric with the additional amount of air, which is why capacity of the injectors and the pulse-width range of the control electronics are important.
Now, turbos run HOT because they use exhaust gas which is hot. All that heat sits under the hood. I know about this, because a friend and I just got done replacing all the rubber under the hood of his RX-7 TT. It even has a circuit on it that lets the engine run for a few minutes when you turn the key off to cool down the turbo bearings and oil so it doesn't coke off. Whereas on my other friends stock supercharged intercooler SVT, it stays pretty cool under the hood. Yes there are things you can do to mitigate the heat of turbos, but it's tough and you still have the bearing oil temperature problem. Where as with a supercharger, they don't run off of exaust gases and don't put all that heat in the engine compartment. For an already high compression ratio engine, with already good breathing that doesn't require a lot of boost (compression) to get more air flowing into the engine a supercharger is the right choice especially when you consider the less heat under the hood benefit and when what you want to do is force as much air in the engine as you can without causing it to prematurely fail. So I understand his desire for a supercharger in lieu of a turbo charger and agree with it. Can the engine handle more boost as with a turbo charger? He should know. Will you get more HP with turbos versus supercharger? He should know.
Supercharger for me please!!!!!
Enforcer
BTW, you can trick the ECM with some electronics (more than just a resistor) and even better if you add a different kind (expensive) O2 sensor. And O2 sensors have to heat up first before they start working, which is why your engine runs differently when it is cool, the ECM is not controlling yet. Enter the 3 wire O2 sensor years ago, the third wire is for pre-heating so the ECM can start controlling emissions earlier.
The emissions system or Emissions Control Module (ECM) is a closed loop feedback control system. It monitors the Oxygen sensors (yes plural for the Z, I have pictures) and adjusts the amount of fuel being delivered by the injectors to lean or richen the air/fuel mixture. Rich mixture means more power but also more polutants and the output voltage of the oxygen sensor changes. There are several types, still waiting on the Shop Manual to know what type is used on the Z. I am most familiar with the O2 sensor that toggles around .5 volts.
So, if you want to fool the ECM into thinking it's lean when it is actually rich then you have to fool the oxygen sensor. However, this type of oxygen sensor isn't easy to fool. Because it toggles around .5 Volts. By that I mean it never stays on .5 Volts. It does not have a linear ouput, it really jumps with a little change in O2. You can think of this type of sensor/feedback/control as a bang-bang control. One instant it is like .01 volts, the next instant it is over 1.0 volts as the ECM constantly adjusts more/less fuel. But what is amazing is how fast it does this and how little of a change in fuel (air/fuel mixture) it takes. So you can only fool it a little bit because eventually the computer has to bang back to lean and the only way it can do that is if it gets a sensor reading that requires a lean mixture to produce. So if you don't fool it correctly, the ECM probably detects a fault because it never goes lean or doesn't go lean often enough, probably lights the check engine soon lamp and goes into a default mode using pre-determined fuel amount settings in the ECU. IE default mode for a broke O2 sensor. Ok, so all you have to do is change the default fuel amounts so it will run rich once it reaches that mode and voila more power, but crappy emissions. Hence why you need to reprogram/rewire the ECM/ECU to change the default fuel settings for a broke O2 sensor mode.
If you bring in more air, then the ECM detects a lean mixture from the voltage on the O2 sensor and commands more fuel. Emissions are increased for lean mixtures too. Been a long time but I think rich fuel mixture yields increased hydrocarbons and lean yields more nitrogen oxides (NOX). Both types of emissions are what EPA is trying to reduce. So the ECU is always trying to control the Air/Fuel mixture to stoichiometric or about 14:1. At stoichiometric, you have the best situation for least hydrocarbons and least nitrogen oxides. So that is what the ECM does, it continuously reads the O2 sensor and adjusts the amount of fuel being delivered to achieve stoichiometric. Now it gets a little more complicated when you introduce acceleration/deacceleration and air temperature which means air mass and that is where the mass air flow sensor comes into play. The goal of the emissions system is to reduce emissions at all times under all conditions, cold engine, warm engine, high and low air temperatures , iddling, accelerating etc. As EPA reduces the allowable manufacturers emissions, the circuitry has to get more complicated to reduce emissions under all conditions.
That is why HP advantages by non-breathing improvement ad-ons won't add-on HP if the emissions are the same because the ECM is controlling the mixture. You have to fool the circuitry as well.
If you put on any type of intake (properly designed with info from Nissan that enhances breathing over the stock which is already pretty good) or Forced Induction which will need a bigger input pipe (plenum and MAF sensor) for best efficiency, you are moving more air into the engine and the ECM compensates by adding more fuel to avoid lean emissions. Which means more power. However as you force more air into the engine, you do two things. First you compress the air, which effectively raises the compression ratio and there is a limit (by design of engine internals - heads cranks bores etc). Secondly when you compress air it heats up. So you need an intercooler to cool the air after it is compressed but before it enters the engine to extend engine life and to get the yield out of the increased breathing (cooler air more HP). At the same time, the injectors and the computer that controls them (ECM/ECU) has to be able to provide the extra amount of fuel to maintain stoichiometric with the additional amount of air, which is why capacity of the injectors and the pulse-width range of the control electronics are important.
Now, turbos run HOT because they use exhaust gas which is hot. All that heat sits under the hood. I know about this, because a friend and I just got done replacing all the rubber under the hood of his RX-7 TT. It even has a circuit on it that lets the engine run for a few minutes when you turn the key off to cool down the turbo bearings and oil so it doesn't coke off. Whereas on my other friends stock supercharged intercooler SVT, it stays pretty cool under the hood. Yes there are things you can do to mitigate the heat of turbos, but it's tough and you still have the bearing oil temperature problem. Where as with a supercharger, they don't run off of exaust gases and don't put all that heat in the engine compartment. For an already high compression ratio engine, with already good breathing that doesn't require a lot of boost (compression) to get more air flowing into the engine a supercharger is the right choice especially when you consider the less heat under the hood benefit and when what you want to do is force as much air in the engine as you can without causing it to prematurely fail. So I understand his desire for a supercharger in lieu of a turbo charger and agree with it. Can the engine handle more boost as with a turbo charger? He should know. Will you get more HP with turbos versus supercharger? He should know.
Supercharger for me please!!!!!
Enforcer
BTW, you can trick the ECM with some electronics (more than just a resistor) and even better if you add a different kind (expensive) O2 sensor. And O2 sensors have to heat up first before they start working, which is why your engine runs differently when it is cool, the ECM is not controlling yet. Enter the 3 wire O2 sensor years ago, the third wire is for pre-heating so the ECM can start controlling emissions earlier.
Damn!!! Those Alabama people Are smart!!!
10-17-2002, 07:46 PM
#68
Registered User
There is always more power to be made with turbo (b/c you can always do something to up your boost, however, after we get to 9psi it's going to be costly). I believe if we get a SC and a TC running at the same pressure in our cars the TC will make more power. Also, there's a lot circulating around discussing turbos not being reliable. While it is true that turbo's require more maintance, they are very capable of running with no problems. For those of you thinking SCs are super reliable, think again. They can cause problems as well. There have been plenty of people w/ JR sc's that ahve had problems. It all comes down to how well you care for your car. Also, I wouldn't worry about running boost on our engines as long as you do it in moderation (I would say around 9 psi, intercooled, can we say 400?). There are RSX-Ss out there that are turbocharged and they have a higher Cr than we do. Also I would like to note to all that turbos are more effiecient. SCs cost power to make power while TCs are pretty efficient.
Also, I belive if NISMO offers and sort of FI kit it will not be covered under warranty (sorry, I would like it too, but it's not going to happen).
IA: Please ask the guy what we can to to recover the 320hp NA that the engine is capable of. PM me!!!
Also, I belive if NISMO offers and sort of FI kit it will not be covered under warranty (sorry, I would like it too, but it's not going to happen).
IA: Please ask the guy what we can to to recover the 320hp NA that the engine is capable of. PM me!!!
10-17-2002, 07:47 PM
#69
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Internet Abyss,
While I don't own a 350z, I do have a 2002 Sentra SE-R spec-v, and do admire the 350z and Nissans in general. I found a link to this post from the forum I usually go to www.b15sentra.net. If you don't mind, I have a couple of questions relating to the spec-v that I would appreciate you asking the Nissan Engineer.
1) What was changed in the 6-speed manual from the 2002 to 2003 model years other than just the gear ratios? Did they fix the clunky, hard shifting?
2) (While not applicable to my car) What did Nissan do to correct the oil burning problems found on some 2.5 litre engines?
Also, maybe you can convince the engineer to register and post at this forum, and perhaps www.b15sentra.net ? At least that will make your life a little easier, and maybe help your phone bill too.
Thanks.
While I don't own a 350z, I do have a 2002 Sentra SE-R spec-v, and do admire the 350z and Nissans in general. I found a link to this post from the forum I usually go to www.b15sentra.net. If you don't mind, I have a couple of questions relating to the spec-v that I would appreciate you asking the Nissan Engineer.
1) What was changed in the 6-speed manual from the 2002 to 2003 model years other than just the gear ratios? Did they fix the clunky, hard shifting?
2) (While not applicable to my car) What did Nissan do to correct the oil burning problems found on some 2.5 litre engines?
Also, maybe you can convince the engineer to register and post at this forum, and perhaps www.b15sentra.net ? At least that will make your life a little easier, and maybe help your phone bill too.
Thanks.
10-17-2002, 08:28 PM
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hmmmm....my car is fixed so i probably will only get one more phone call...I hope he will have a LONG conversation with me....
Enforcer....I liked your post....I barely understand it....but it sounded ALOT like the stuff he was talking about....
You said in your post something about 14.1 ratio.....I distinctly remember him saying something about 17.1 I have know idea what about....this stuff is way above me....I wish one of you techies was talking to this guy....he might give you a job...LOL
MY CAR IS FIXED
Still happy
Enforcer....I liked your post....I barely understand it....but it sounded ALOT like the stuff he was talking about....
You said in your post something about 14.1 ratio.....I distinctly remember him saying something about 17.1 I have know idea what about....this stuff is way above me....I wish one of you techies was talking to this guy....he might give you a job...LOL
MY CAR IS FIXED
Still happy
10-17-2002, 09:25 PM
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Porshekiller if you knew me....you would know that is a dumb question
They took care of me with freebies since I lost a total of 6.5 days of Z driving time and had a sub par dealer experience.
They gave rental cars during that time too...so it was a fair trade off IMO
ALSO...My Z resents the remark about being defective....she was just born alittle special. She is fine now.
They took care of me with freebies since I lost a total of 6.5 days of Z driving time and had a sub par dealer experience.
They gave rental cars during that time too...so it was a fair trade off IMO
ALSO...My Z resents the remark about being defective....she was just born alittle special.
She is fine now.
Last edited by InternetABYSS; 10-17-2002 at 09:30 PM.
10-17-2002, 09:58 PM
#75
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Originally posted by InternetABYSS
Porshekiller if you knew me....you would know that is a dumb question
They took care of me with freebies since I lost a total of 6.5 days of Z driving time and had a sub par dealer experience.
They gave rental cars during that time too...so it was a fair trade off IMO
ALSO...My Z resents the remark about being defective....she was just born alittle special. She is fine now.
Porshekiller if you knew me....you would know that is a dumb question
They took care of me with freebies since I lost a total of 6.5 days of Z driving time and had a sub par dealer experience.
They gave rental cars during that time too...so it was a fair trade off IMO
ALSO...My Z resents the remark about being defective....she was just born alittle special.
She is fine now.
10-17-2002, 11:00 PM
#76
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Originally posted by frayed
That was the most rudimentary and techinically inaccurate discussion of thermodynamics and engine control management I've read in a long, long time.
That was the most rudimentary and techinically inaccurate discussion of thermodynamics and engine control management I've read in a long, long time.
.
10-17-2002, 11:16 PM
#77
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Originally posted by channone
I think your Z must have come over in a "short boat" unlike the rest of ours.
I think your Z must have come over in a "short boat" unlike the rest of ours.
The short yellow school boat...funny. If I had time I would photoshop the visual I got from that...hee hee
porcshekiller......No need to be sorry I'm just playing....its funny I had these problems...oh well its fixed. (i hope)
10-17-2002, 11:36 PM
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Uhm, what your engineer guy told you about the intake makes no sense at all. I don't know if the car uses a MAP or MAF sense for the intake, but either way the ECU doesn't have a say in things up to a point.
If power gains can't be had from an intake, it's because the car already has a really good air intake. Same thing goes for the exhaust.
If power gains can't be had from an intake, it's because the car already has a really good air intake. Same thing goes for the exhaust.
