How the ECU works and what needs to be overcome for NA gains
05-09-2005, 07:25 PM
#22
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Originally Posted by Nano
what about resetting ECU each morning?
That way when you wanted to play, the car would be fast, and when you wanted to conserve fuel, the car would be slower. :PIt would be cool to have a laptop hooked up, and some performance settings to pick from. It would be like an advanced version of the "fuel economy/performace" buttons they used to put in cars (which btw, didn't work worth a ****).
Last edited by phile; 05-09-2005 at 07:27 PM.
05-09-2005, 07:48 PM
#23
I'm not 100% sure, but I think a reset ECU won't perform as well as a car that does nothing but WOT. I wonder if the ECU might have the capability to advance timing and fuel a little bit (though probably not much) over the starting point that the ECU resets to. I guess the way to tell would be if you took your car to the dyno, reset the ECU and dynoed. Then tracked the car for a few 20 min sessions, turn the car off and let it cool. Then trailer it to the dyno and see what numbers you get. I wonder if they'd be slightly higher after doing the track day.
things like this, no one REALLY seems to know
things like this, no one REALLY seems to know
05-09-2005, 07:52 PM
#24
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I scratch my head at this thread; this is my impression of how our ecu works with mods.
Here are my mods:
K&N Drop in: Ever so Slightly increase air mass thus air/fuel ratio drops.
Comment if I screwed up here... This thread is confusing me; I think I need some beer...
Anyways, so you need to "trick" the ECU when you have a bunch of N/A mods.
When do you draw the line? When would I cross the line where I should start playing with the ECU, or have a crossed the line already?
Here are my mods:
K&N Drop in: Ever so Slightly increase air mass thus air/fuel ratio drops.
ECU compensates by adding fuel to balance?
AAM Spacer: Increase of air mass, especially to front cylinders (rumored to run rich) ECU compensated by adding more fuel to balance air fuel ratio?
Y-pipe:Faster gas expulsion not necessarily increase in air mass or fuel quantity. ECU compensates by adding more fuel? Since exhaust gets expelled faster less time to analyze fuel?? (Not sure on this one....)
So all my mods have (theoretically) added air to the mixture and the ecu by design should have added more fuel to compensate to maintain the pre programmed ratio.Comment if I screwed up here... This thread is confusing me; I think I need some beer...
Anyways, so you need to "trick" the ECU when you have a bunch of N/A mods.
When do you draw the line? When would I cross the line where I should start playing with the ECU, or have a crossed the line already?
05-09-2005, 08:07 PM
#25
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Originally Posted by sentry65
I'm not 100% sure, but I think a reset ECU won't perform as well as a car that does nothing but WOT.
Originally Posted by sentry65
I wonder if the ECU might have the capability to advance timing and fuel a little bit (though probably not much) over the starting point that the ECU resets to. I guess the way to tell would be if you took your car to the dyno, reset the ECU and dynoed. Then tracked the car for a few 20 min sessions, turn the car off and let it cool. Then trailer it to the dyno and see what numbers you get. I wonder if they'd be slightly higher after doing the track day.
things like this, no one REALLY seems to know
things like this, no one REALLY seems to know
About 2 years ago there was talk about having the dealers advance timing with the ConsultII device. One guy that I know of on this board actually had it done. He said he felt a little more power, from waht I remember. So say the dealership upped it 2 degrees. The ECU would then have to ability to add back two degrees if it ever dropped to zero or below. But without having the timing advanced on the Consult II, I would assume it could only be advanced up to the initial stock level, which in our scenario would be 0. Basically the ConsultII changes the limits.
05-09-2005, 08:08 PM
#26
the7ferret, don't take this the wrong way, but you don't have many NA mods
not enough, to the point where the ECU issues will effect you. And yes I believe in your case, since you have just slightly more airflow than stock, the ECU will give you more fuel to compensate.
The issue is for us people who have a lot of NA mods and going past the emissions and MAF voltage threshold where the ECU isn't happy anymore and thus starts adjusting things to reduce the power back down to "stock" levels
by "stock" levels, I mean stock give or take 10-15whp or so.
The ECU has to be able to compensate for different octane gas and different altitudes and climates/temps
As far as it knows, you're driving at a very low (below sea level) altitude in an extremely cold temperature. It has no idea that parts on the car have been changed. It was programmed with some room to adjust. But the engineers decided that anything beyond that small headroom, there must be something wrong and thus gave the ECU a sequence of steps to adjust itself to get back to that stock range.
not enough, to the point where the ECU issues will effect you. And yes I believe in your case, since you have just slightly more airflow than stock, the ECU will give you more fuel to compensate.
The issue is for us people who have a lot of NA mods and going past the emissions and MAF voltage threshold where the ECU isn't happy anymore and thus starts adjusting things to reduce the power back down to "stock" levels
by "stock" levels, I mean stock give or take 10-15whp or so.
The ECU has to be able to compensate for different octane gas and different altitudes and climates/temps
As far as it knows, you're driving at a very low (below sea level) altitude in an extremely cold temperature. It has no idea that parts on the car have been changed. It was programmed with some room to adjust. But the engineers decided that anything beyond that small headroom, there must be something wrong and thus gave the ECU a sequence of steps to adjust itself to get back to that stock range.
05-09-2005, 08:11 PM
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Originally Posted by sentry65
yeah I know, we have no way to know for sure that guy really was a nissan engineer, but the interviewer used to own part of my350z.com so unless he was lying to us, or yeah if the engineer wasn't who he said he was.
I thought the info seemed pretty genuine though from how it was written. I'm not sure WHY a nissan engineer would discuss the ECU etc - maybe he's allowed to with no repurcussions? It's not like they're really trade secrets so much since the car is out on the market and people will eventually figure it all out anyway. Most modern cars work that way these days anyway
I thought the info seemed pretty genuine though from how it was written. I'm not sure WHY a nissan engineer would discuss the ECU etc - maybe he's allowed to with no repurcussions? It's not like they're really trade secrets so much since the car is out on the market and people will eventually figure it all out anyway. Most modern cars work that way these days anyway
Yes he was a NNA's head engineer for all the service departments in the US....He worked with a team of engineers that arrange/deploy all the new vehicals when launched. THere is a nissan north america HQ in my area (Dallas TX)...and in california. At the time we were information ****** trying to figure out whatever about the Z while we were waiting 6 months or more for it. I got alot of contacts back then press kits, special appearances auto graphs, free extended warrantees, lots of free goodies. The other co-owner of the site actually got a test 350z vehical from Nissan to drive around the west coast for a week.
Back to the original write up. My car which was one of the first 1000 cars off the line. Needless to say it got attention because the transmission lasted like 4 days...LOL Mine was the very first 350z tranny to fail and get replaced. My car bottomline had every freaking thing wrong that was out there. ( I still have it FYI) They were also dancing around and kissing booty, calling me all the time making sure I was happy that they were getting things worked out. I think mainly since with my350z I could easily put a huge dent into their sales if I was pissed. So needless to say they sent the entire crew to inspect it and replace it. I also got the PR touch and put in constant contact with the guy thats incharge of training all the service departments at all the dealerships in the USA was a big plus. He personally worked with the original designers of the 350z so that he could setup all the service procedures to be deployed on the 350z. So i did my best to ask him whatever I could think of and he explained it with out pausing. THis guy was so important I name droped him anytime a delaership service departmetn would give me crap... They would immediatly change their tune. I also talked to most of the designers out of that lust and love z book. So yes the buck stoped with him ....(well as far as a english speaking person
) To be honest with you someone like yourself should have been the one drilling him...could have got more out of it and understood it all.
Here was the only issue with the information....Im NOT a mechanic and had very basic understanding so I tried to take notes and have them explain everything for me. I guess Nismo didnt want to do the liablity for a turbo or superchager after all..But old members remeber when NISMO sent us surveys and turbos/superchargers were on it. I reread the write up I did linked above and I think I was on target using hind sight now. Also realize I tried to put this together after a 2 hour phone conversation with him and I met him for like 20 when he flew in to test drive the car with me after it was fixed.
Its been like 3 years so I dont remeber all the names anymore.
05-09-2005, 08:19 PM
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Sentry:
Your right, I dont have crap for mods, my camera is to blame for that... Anyways, looking at your list of mods i can see where the ECU can become problematic; Cams, Cats, TB, Flash...
Your right, I dont have crap for mods, my camera is to blame for that... Anyways, looking at your list of mods i can see where the ECU can become problematic; Cams, Cats, TB, Flash...
05-09-2005, 08:25 PM
#29
InternetABYSS, just wanted to say thanks a lot for everything you've done - I hold that thread to be one of the great sources of info out the ECU and think you did a great job relaying it back to everyone even if you had trouble understanding it all.
I wasn't around on the boards then, but always come back to that thread to reread the 1st page. Back then there was so little hardcore info about the car, but I think everyone seemed to get more excited about a factory FI option than getting the car to actually gain power.
thanks for posting that - now we can say it's reliable info for sure.
As a side note, my mom had one of the very first murano's off the line and it had some sort of major engine problem. The head designer/engineer flew in town to personally evaluate it - her car just cut off and lost power, so was kinda a potential big deal. I think it turned out to just be just some crazy glitch in her car, but they ended up replacing the engine and transmission anyway. So just goes to show you, I think nissan pays extreme attention to the first cars that go out into the world - and they should since they could get sued if they don't catch any potentially fatal flaws.
BTW everyone, here's another bit quoted by InternetABYSS about what the engineer said for those who don't want to wade thru the whole thread:
I wasn't around on the boards then, but always come back to that thread to reread the 1st page. Back then there was so little hardcore info about the car, but I think everyone seemed to get more excited about a factory FI option than getting the car to actually gain power.
thanks for posting that - now we can say it's reliable info for sure.
As a side note, my mom had one of the very first murano's off the line and it had some sort of major engine problem. The head designer/engineer flew in town to personally evaluate it - her car just cut off and lost power, so was kinda a potential big deal. I think it turned out to just be just some crazy glitch in her car, but they ended up replacing the engine and transmission anyway. So just goes to show you, I think nissan pays extreme attention to the first cars that go out into the world - and they should since they could get sued if they don't catch any potentially fatal flaws.
BTW everyone, here's another bit quoted by InternetABYSS about what the engineer said for those who don't want to wade thru the whole thread:
First he told me to get to more power or more gotta make the cpu think the emissions are still there even if you removed them then add mods.
To get best out of stock setup (320) change the timing, air/fuel mapping and stuff in the programing...and also said something about makeing the stock mass air flow system go from 20 something to 30 something....That are the future fatory mods for the Z unless they decide to change the motor by going in it...the future stuff isnt set...
He definitly gave me the impression that there is alot more power in tuning the ECU...actually he called it ECM
He said that is what nissan has done in the past to increase power in the altimas and maximas
Obiviosly I asked him to do it on my car now....he chuckled ...I keep putting a bird in his ear that we are dying for more hp and that whoever makes mods that produce gains has alot of money to make
To get best out of stock setup (320) change the timing, air/fuel mapping and stuff in the programing...and also said something about makeing the stock mass air flow system go from 20 something to 30 something....That are the future fatory mods for the Z unless they decide to change the motor by going in it...the future stuff isnt set...
He definitly gave me the impression that there is alot more power in tuning the ECU...actually he called it ECM
He said that is what nissan has done in the past to increase power in the altimas and maximas
Obiviosly I asked him to do it on my car now....he chuckled ...I keep putting a bird in his ear that we are dying for more hp and that whoever makes mods that produce gains has alot of money to make
Last edited by sentry65; 05-09-2005 at 08:40 PM.
05-09-2005, 08:44 PM
#30
here's an interesting bit of info posted by Enforcer who I don't think has posted for a couple years now:
wow A/F = 14, doesn't that sound familiar to many of us with NA mods? My car rarely gets below that A/F and stays there month after month.
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.
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.
Last edited by sentry65; 05-09-2005 at 10:17 PM.
05-09-2005, 11:18 PM
#32
from Sport Z magazine:
interview with Nissan race team, Jackson Stewart
interview with Nissan race team, Jackson Stewart
The stock fuel system limits you to about 300 HP. To make more HP, you need to make significant changes.
it is not a fuel supply issue. Unless they started adding auxilary fuel pumps etc
We know for a fact the biggest issue is the fuel system design from Nissan. It is inadequate to provide greater than about 300HP at the flywheel. It is not necessarily a lean condition but an inconsistent fuel delivery issue. Realize that a guy might make 340 HP on the street but he can only use in excess of 300 HP for a brief period of time. He could not hold his foot to the floor for 40 seconds while banking a turn at Daytona.
.....One of the problems we found early on is the stock fuel tank. At Willows, we found we had fuel starvation problems in turns 2 and 9 which are long, fairly high G right-hand corners. (then goes on how they built a custom fuel cell etc)
I think the problem is they designed the motor to do what is needed to deliver good performance and durability in stock form and did not put real margins in for tuners. Nissan produced a very good system in stock. They just did not build in margins for tuners in the areas of fuel managment and electronics. You need to improve those systems if you want to add more power
it is not a fuel supply issue. Unless they started adding auxilary fuel pumps etc
We know for a fact the biggest issue is the fuel system design from Nissan. It is inadequate to provide greater than about 300HP at the flywheel. It is not necessarily a lean condition but an inconsistent fuel delivery issue. Realize that a guy might make 340 HP on the street but he can only use in excess of 300 HP for a brief period of time. He could not hold his foot to the floor for 40 seconds while banking a turn at Daytona.
.....One of the problems we found early on is the stock fuel tank. At Willows, we found we had fuel starvation problems in turns 2 and 9 which are long, fairly high G right-hand corners. (then goes on how they built a custom fuel cell etc)
I think the problem is they designed the motor to do what is needed to deliver good performance and durability in stock form and did not put real margins in for tuners. Nissan produced a very good system in stock. They just did not build in margins for tuners in the areas of fuel managment and electronics. You need to improve those systems if you want to add more power
05-10-2005, 12:43 AM
#33
so how would exhaust mods take place in this situation? do these matter in those ECU probs becuz isnt it mostly freeing up the pressure and just letting all the gases out? I kno that the test pipes have a big part because of those 02 bungs. but like a catback exhaust doesnt have much to do with the ecu rite since there arent any sensors around that area. Most people just do the intake, plenums, headers, test pipes, and cat back exhaust as NA mods. so can anyone plz describe how everyone of these mods would affect the ecu/power gain prob? sorri if this doesnt realli make sense, i dont even kno how to put these thots into words, haha.
05-10-2005, 01:49 AM
#34
i know next to zilch about engines so this thread is way over my head, but i have dumped lots of cash into my z for na mods with disappointing results. i have also been subscribed to the "interesting conversation with a nissan engineer" thread for a long time, because it seemed like this guy really knew how to get more out of our na mods.
Question: after all this time, why hasn't someone figured out the "cheap way to trick the sensor with a resistor and screw"? After all this time, why hasn't someone figured out the "specs/diagram of the ecu and the WIRE (not wires) that needs to be cut and resistors to be placed"?
Hello, are you there, TS and AAM?
Question: after all this time, why hasn't someone figured out the "cheap way to trick the sensor with a resistor and screw"? After all this time, why hasn't someone figured out the "specs/diagram of the ecu and the WIRE (not wires) that needs to be cut and resistors to be placed"?
Hello, are you there, TS and AAM?
05-10-2005, 03:27 AM
#35
Sentry, I would like to know how much power that you believe is being left on the table from the ECU issues. Your dyno came out at 280ish. Thats almost 45 more rwhp than stock. You are probably around 330-340 at the crank. Are you disappointed with that? I personally think that 45 rwhp is not an unreasonably small amount of power to gain compared to other N/A cars. Lets say worst case scenerio is you are losing how much? 10hp? 15?
My other issue is this, don't you dyno at WOT? Doesn't the TS Flash run the motor at that point? Bypassing all the crap? I don't know for sure, but I believe how that's how it works.
I don't think this motor is just going to give up free and easy power. The VQ is already in a pretty decent state of tune with a great airbox. It has always been about the combination of mods on N/A cars. They all have to be engineered together. Check out that Australian guy's thread about his S1 motor. He's running full Motec and has almost everything including nismo pistons, cams etc. He was a bit disappointed with his results too. More power will be found by desiging the parts to work together than through tweaking the ECU.
Just for reference your mod list is this; (left the 3.9 out because technically that doesn't add hp.)
JWT cams
Tilton Clutch/Flywheel
Crawford headers
Crawford plenum
Crawford cats
JWT popcharger
350EVO throttlebody
Nismo exhaust
Technosquare ECU flash
UR crank pulley
Sentry, you have pm.
My other issue is this, don't you dyno at WOT? Doesn't the TS Flash run the motor at that point? Bypassing all the crap? I don't know for sure, but I believe how that's how it works.
I don't think this motor is just going to give up free and easy power. The VQ is already in a pretty decent state of tune with a great airbox. It has always been about the combination of mods on N/A cars. They all have to be engineered together. Check out that Australian guy's thread about his S1 motor. He's running full Motec and has almost everything including nismo pistons, cams etc. He was a bit disappointed with his results too. More power will be found by desiging the parts to work together than through tweaking the ECU.
Just for reference your mod list is this; (left the 3.9 out because technically that doesn't add hp.)
JWT cams
Tilton Clutch/Flywheel
Crawford headers
Crawford plenum
Crawford cats
JWT popcharger
350EVO throttlebody
Nismo exhaust
Technosquare ECU flash
UR crank pulley
Sentry, you have pm.
05-10-2005, 03:38 AM
#36
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I think it was Tony from Performance or maybe another of our sponsor/vendors that said it best. You guys are giving the ECU supernatural magic powers. I don't believe any automotive ECU is as sophisticated as you all proport it to be. It is there to control a set of parameters to a point but it can't do all this mod negating stuff to the level all these theories propose.
The truth is we may never know just how it operates since only the real Nissan engineers that design the ECU's for them know the code they wrote and what the requirements and specs were for the Z project.
This is my theory on our ECU.....................................
The truth is we may never know just how it operates since only the real Nissan engineers that design the ECU's for them know the code they wrote and what the requirements and specs were for the Z project.
This is my theory on our ECU.....................................
05-10-2005, 04:09 AM
#37
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Subscribing. Good info here.I have slowed down from buying new mods(internal engine mods) because of the "ECU" issue. Also if you think we are trying to figure something out now. Wait until the GTR comes out. Thats a whole different piece of the puzzle we need to figure out if they use a VQ. Which is likely.
Last edited by pimp1911; 05-10-2005 at 04:14 AM.
05-10-2005, 05:44 AM
#38
Originally Posted by sentry65
yeah, my car did 281 whp on my last dyno in AZ on 91 octane at around 1500 ft above sea level.
If I wasn't running 1 step colder plugs, I'd make a few hp more I'd guess.
Also my car is misfiring. It didn't start happening until after my TS flash. I've sent it back to them 3 or 4 times and they say there isn't anything they can do about it and that multi misfiring is in fact common on this car with their flash...
So I have to reset the computer all the time. It drives great when it's reset. But as soon as the SES light comes on, it SUCKS to drive - wants to stall, less power, more jittery throttle response, etc etc
TS told me to try 1 step colder plugs, but that didn't help anything other than make me lose some power. Apparently my engine is not misfiring when the ECU is reset, but does so after it gives the SES light. That's suspicious to me. The ECU is doing something to cause it and I bet it's cause I don't meet the expected emissions or MAF voltage and don't have enough fuel going into the engine. So I'm pretty sure I need to upgrade my fuel system, find a way to control my MAF voltage, and get the O2 sensors under control. Only simple way to do that is an EMS with the non-fouler O2 sensor tweak that I can see.
that's my experience...
If I wasn't running 1 step colder plugs, I'd make a few hp more I'd guess.
Also my car is misfiring. It didn't start happening until after my TS flash. I've sent it back to them 3 or 4 times and they say there isn't anything they can do about it and that multi misfiring is in fact common on this car with their flash...
So I have to reset the computer all the time. It drives great when it's reset. But as soon as the SES light comes on, it SUCKS to drive - wants to stall, less power, more jittery throttle response, etc etc
TS told me to try 1 step colder plugs, but that didn't help anything other than make me lose some power. Apparently my engine is not misfiring when the ECU is reset, but does so after it gives the SES light. That's suspicious to me. The ECU is doing something to cause it and I bet it's cause I don't meet the expected emissions or MAF voltage and don't have enough fuel going into the engine. So I'm pretty sure I need to upgrade my fuel system, find a way to control my MAF voltage, and get the O2 sensors under control. Only simple way to do that is an EMS with the non-fouler O2 sensor tweak that I can see.
that's my experience...
05-10-2005, 06:11 AM
#39
yes 281 SAE corrected, I think doug's car at crawford is pulling more power than me though.
My dyno did something odd.
all 3 runs I did pretty much 281, ,but the 3rd one my A/F was a full bar higher than the first 2 runs
Why would my A/F change during the coarse of the dyno? I was doing WOT runs.
I'm not thinking there's TONS of power to get out of the MAGIC box as some of you say. I think there's some potential power, but maybe not a lot. What I want is the ECU to stop trying to negate mods. I'm tired of having ot reset my ECU every 2 days. I'm tired of people not knowing how the ECU works and dismissing it as either a "magic box" or "simple A/F regulator" because I don't think it's either. I think Nissan designed the car for stock purposes and that's it. Anything beyond that and you have to fight it for power.
I think the ECU and fuel system are the 2 major things holding my car back from being able to drive like a normal car.
If all the ECU does is try to give you a "good" A/F then it's not doing it's job. Everyone here is running lean who starts adding on bolt ons. That makes the car knock if you go too lean, and the car starts pulling power and doing all the stuff mentioned until it sucks.
I've tracked my car in safe mode with 103 octane. And when I was done for the day, my car actually felt stronger than when I reset the ECU on a normal day going to work. With 103 octane, it's doubtful it was pinging. Granted My A/F isn't great and seems to get a different number every time I dyno. TS and I have gone back and forth a few times and 2 ideas come to mind as to why my A/F is always sucking. Either TS doesn't know how to add fuel to my car - and I doubt this. Or the ECU variables keep changing. I'm on 91 octane gas here which I'm sure wasn't meant for the Z. In my case especially it's probably hurting my performance because it probably quickly gets knock. I've been using Shell 91 gas. Seems to be the best I can find out here. I occasionally use 101 octane or mix in 101 with 91 and it does drive smoother. Way smoother. I can't say it feels any more powerful though. For normal driving 101 octane is probably causing me to lose power.
I think my car runs richer in safe mode and leaner in normal mode. I think I'm losing power because the ECU just won't give me fuel. Obviously I may have a fuel deficency issue. I probably need more fuel to make more power. Maybe my ECU would even calm down. The return fuel systems are finally out now and most all the bugs have been worked out. I've been saving up some money to upgrade to it and some higher injectors and fuel pump as well as a good way to tune it.
With all the reading I've done, I think an EMS is just about the only solution to get the ECU to stop messing around with things. More power is a potential side effect.
I'll have to recheck out that austrailian guy's thread with the motec. I read it once I think a long time ago, but wasn't so interested in it at the time. I'm curious what all his setup was and what his findings were.
Like I said, as soon as I got the TS flash, I started getting misfiring. They said it was happening in a lot of cars and to just ignore it. Thing is, you CANT ignore it - it's night and day when that SES light comes on vs normal driving.
It might be I just need more fuel and the ECU is trying to give it to me, but can't so it starts pulling timing. But that doesn't explain why people with E-manages and Apexi SAFCII's get a perfect tune, then a few days or months later, their tune is shot and negated.
My dyno did something odd.
all 3 runs I did pretty much 281, ,but the 3rd one my A/F was a full bar higher than the first 2 runs
Why would my A/F change during the coarse of the dyno? I was doing WOT runs.
I'm not thinking there's TONS of power to get out of the MAGIC box as some of you say. I think there's some potential power, but maybe not a lot. What I want is the ECU to stop trying to negate mods. I'm tired of having ot reset my ECU every 2 days. I'm tired of people not knowing how the ECU works and dismissing it as either a "magic box" or "simple A/F regulator" because I don't think it's either. I think Nissan designed the car for stock purposes and that's it. Anything beyond that and you have to fight it for power.
I think the ECU and fuel system are the 2 major things holding my car back from being able to drive like a normal car.
If all the ECU does is try to give you a "good" A/F then it's not doing it's job. Everyone here is running lean who starts adding on bolt ons. That makes the car knock if you go too lean, and the car starts pulling power and doing all the stuff mentioned until it sucks.
I've tracked my car in safe mode with 103 octane. And when I was done for the day, my car actually felt stronger than when I reset the ECU on a normal day going to work. With 103 octane, it's doubtful it was pinging. Granted My A/F isn't great and seems to get a different number every time I dyno. TS and I have gone back and forth a few times and 2 ideas come to mind as to why my A/F is always sucking. Either TS doesn't know how to add fuel to my car - and I doubt this. Or the ECU variables keep changing. I'm on 91 octane gas here which I'm sure wasn't meant for the Z. In my case especially it's probably hurting my performance because it probably quickly gets knock. I've been using Shell 91 gas. Seems to be the best I can find out here. I occasionally use 101 octane or mix in 101 with 91 and it does drive smoother. Way smoother. I can't say it feels any more powerful though. For normal driving 101 octane is probably causing me to lose power.
I think my car runs richer in safe mode and leaner in normal mode. I think I'm losing power because the ECU just won't give me fuel. Obviously I may have a fuel deficency issue. I probably need more fuel to make more power. Maybe my ECU would even calm down. The return fuel systems are finally out now and most all the bugs have been worked out. I've been saving up some money to upgrade to it and some higher injectors and fuel pump as well as a good way to tune it.
With all the reading I've done, I think an EMS is just about the only solution to get the ECU to stop messing around with things. More power is a potential side effect.
I'll have to recheck out that austrailian guy's thread with the motec. I read it once I think a long time ago, but wasn't so interested in it at the time. I'm curious what all his setup was and what his findings were.
Like I said, as soon as I got the TS flash, I started getting misfiring. They said it was happening in a lot of cars and to just ignore it. Thing is, you CANT ignore it - it's night and day when that SES light comes on vs normal driving.
It might be I just need more fuel and the ECU is trying to give it to me, but can't so it starts pulling timing. But that doesn't explain why people with E-manages and Apexi SAFCII's get a perfect tune, then a few days or months later, their tune is shot and negated.
