Discussion
Answer to both is a yes Sir.
If you take a look half way down this page www.efilive.com/supvehicle.aspx
You will see the support for the HSV (Vauxhall VXR) listed under "Gen IV LS2 E40 ECM - Stream S-LS2A"
Woops, sorry also forgot to say wideband support is included (But not the device itself) V2 has 4 Wideband inputs should you want that many. But the LS2 uses narrow bands.
There is a method you can use to tune autove from the narrowband's but its not 100% accurate and while its ok for offload condidtions its not safe/ideal for WOT tuning. Basically you can use the short and long term fuel trims to tell you the % error.
If you take a look half way down this page www.efilive.com/supvehicle.aspx
You will see the support for the HSV (Vauxhall VXR) listed under "Gen IV LS2 E40 ECM - Stream S-LS2A"
Woops, sorry also forgot to say wideband support is included (But not the device itself) V2 has 4 Wideband inputs should you want that many. But the LS2 uses narrow bands.
There is a method you can use to tune autove from the narrowband's but its not 100% accurate and while its ok for offload condidtions its not safe/ideal for WOT tuning. Basically you can use the short and long term fuel trims to tell you the % error.
Edited by ringram on Tuesday 27th February 14:29
Some guys use 2, but 99% only use one. In open loop, when the car is under heavy throttle etc the PCM fuels both banks the same. So you can do one side which should be close to the other. Some guys also tune to one side, then swap the WB (wideband) over and check to make sure that there isnt any engine or exhaust issues.
I got mine off a place in Germany www.lm-1.com they are around £130 by the looks these days.
The LC1 for example and most others have 2 programable outputs, one for wideband and the other for narrowband. You can wire the narrow bands to the ECM using the stock connector if you want to replace one of the stock sensors, or you can create a new bung. The LC1 comes with a threaded bung to use. A new bung is probably the most ideal.
I got mine off a place in Germany www.lm-1.com they are around £130 by the looks these days.
The LC1 for example and most others have 2 programable outputs, one for wideband and the other for narrowband. You can wire the narrow bands to the ECM using the stock connector if you want to replace one of the stock sensors, or you can create a new bung. The LC1 comes with a threaded bung to use. A new bung is probably the most ideal.
Edited by ringram on Tuesday 27th February 17:08
Ill have a go.
First thing to understand is that chemically speaking mixing petrol with O2 in the right amounts to get perfect combustion with no leftovers you need 14.7 parts of air to one part of fuel. (N2 Ar etc dont mix unless you run lean and hot, then you get NOx emissions etc.)
Now the narrowband sensors are designed to be accurate at this point also called stoimetric. They are generally configured to output 0-1V with 450mv being the point of stoich or 14.7:1 mix. (They use zinc chromate or something and measure the difference in resistance between the anode and the cathode which changes based on the O2 content on the inside and outside of the sensor)
On the other hand widebands are designed to opperate accurately over a wide range say from 7:1 to 25:1 some OEM vehicles use them, but they cost more and usually require some sort of calibration. They are ideal for checking how far out the stock PCM is as the narrowbands will simply not see anything other than 14.7:1. The wideband will give you an absolute value.
What you can then do is find out what the ECM is trying to get as far as fueling is concerned and work out the percentage difference between what you read and what the ECM is delivering and adjust the ECM calibration to increase or decrease the fueling. With efilive for example this collection of data is automatic and you are given a % error table to apply to the main fueling or volumetric efficiency table. So you just drive around collecting data and apply the changes and repeat a couple of time until your tune has been dialed in accurately.
The next step after that point is getting spark timing right. Thats a bit harder and requires something else like a dyno or acceleromter to measure power changes resulting from spark timing adjustments.
OEM's use narrowbands because at 14.7:1 thats what produces the most environmentally freindly emissions. Recent advances with direct injection and lean burn engines have led this to change slightly. But the governments standard MOT test doesnt take this into consideration and you will fail if you are running too lean. Maybe because lean = increased NOx emissions as mentioned previously.
The End
Hopefully not too technical and over everyones head.
First thing to understand is that chemically speaking mixing petrol with O2 in the right amounts to get perfect combustion with no leftovers you need 14.7 parts of air to one part of fuel. (N2 Ar etc dont mix unless you run lean and hot, then you get NOx emissions etc.)
Now the narrowband sensors are designed to be accurate at this point also called stoimetric. They are generally configured to output 0-1V with 450mv being the point of stoich or 14.7:1 mix. (They use zinc chromate or something and measure the difference in resistance between the anode and the cathode which changes based on the O2 content on the inside and outside of the sensor)
On the other hand widebands are designed to opperate accurately over a wide range say from 7:1 to 25:1 some OEM vehicles use them, but they cost more and usually require some sort of calibration. They are ideal for checking how far out the stock PCM is as the narrowbands will simply not see anything other than 14.7:1. The wideband will give you an absolute value.
What you can then do is find out what the ECM is trying to get as far as fueling is concerned and work out the percentage difference between what you read and what the ECM is delivering and adjust the ECM calibration to increase or decrease the fueling. With efilive for example this collection of data is automatic and you are given a % error table to apply to the main fueling or volumetric efficiency table. So you just drive around collecting data and apply the changes and repeat a couple of time until your tune has been dialed in accurately.
The next step after that point is getting spark timing right. Thats a bit harder and requires something else like a dyno or acceleromter to measure power changes resulting from spark timing adjustments.
OEM's use narrowbands because at 14.7:1 thats what produces the most environmentally freindly emissions. Recent advances with direct injection and lean burn engines have led this to change slightly. But the governments standard MOT test doesnt take this into consideration and you will fail if you are running too lean. Maybe because lean = increased NOx emissions as mentioned previously.
The End
Hopefully not too technical and over everyones head.
... also the vehicle will use the narrow bands to help it deliver fuel.
The factory ECM is a best guess single attempt which is designed to work with all vehicles in all locations for ever.
It basically looks to see if the voltage is over or below the 450mv level and either adds a litte more fuel or takes a little fuel out. Over time it builds up what are called LTFT Long Term Fuel Trims. For example if at a point in the operating range the engine always needs 5% more fuel then the trim at that point will be 5% and come hell or high water the ECM will put 5% more fuel in no matter what. Over time this can adjust, you can reset these trims by disconnecting the battery etc. Often after doing this you will note the car runs better. Thats because by design at open throttle irrespective of what the actual fueling is the ECM will throw whatever is in the LTFT into the engine as well as the extra fuel required for full throttle.
As you can see from the factory the cars will run rich.
A good tune will result in the ECM having near to zero LTFT values and perfect fueling under throttle.
In fact with a good tune you dont even need the O2 sensors as the actual and requested fueling will be so close they and their mates the fuel trims wont be required. This type of operation is called "Open loop" because the O2 sensors are disable and there is no closed loop system operating. The car is fueled solely off the VE/Fueling table.
A few guys here run open loop including me.
.... well you did ask
The factory ECM is a best guess single attempt which is designed to work with all vehicles in all locations for ever.
It basically looks to see if the voltage is over or below the 450mv level and either adds a litte more fuel or takes a little fuel out. Over time it builds up what are called LTFT Long Term Fuel Trims. For example if at a point in the operating range the engine always needs 5% more fuel then the trim at that point will be 5% and come hell or high water the ECM will put 5% more fuel in no matter what. Over time this can adjust, you can reset these trims by disconnecting the battery etc. Often after doing this you will note the car runs better. Thats because by design at open throttle irrespective of what the actual fueling is the ECM will throw whatever is in the LTFT into the engine as well as the extra fuel required for full throttle.
As you can see from the factory the cars will run rich.
A good tune will result in the ECM having near to zero LTFT values and perfect fueling under throttle.
In fact with a good tune you dont even need the O2 sensors as the actual and requested fueling will be so close they and their mates the fuel trims wont be required. This type of operation is called "Open loop" because the O2 sensors are disable and there is no closed loop system operating. The car is fueled solely off the VE/Fueling table.
A few guys here run open loop including me.
.... well you did ask
Yes in fact its pretty optimal for all tunes. Its when you go full throttle that the closed loop system isnt quite as good as there is a trigger which is based on throttle position or manifold pressure and even rpm based that determines when the richer mixture for open throttle is required. Stock from memory its 64% throttle only that determines power enrichment.
So fuel is added in even when you dont need it.
Closed loop only works when the car is warm and at low load. When cold its open loop and when under throttle its open loop in all cases of tune.
Even open loop you would want 14.7:1 most of the time. Except say over 80kpa manifold pressure. (Moderate to heavy load)
Closed loop with a good tune can run just as good as open loop. Its more consistent too because the fuel trims will keep it inline as the engine wears. Open loop will require a retune for each mod and as the engine wears the tune till not be quite bang on. If you have a tune tool and wideband, this isnt a problem. But for most people they will want to use closed loop.
So fuel is added in even when you dont need it.
Closed loop only works when the car is warm and at low load. When cold its open loop and when under throttle its open loop in all cases of tune.
Even open loop you would want 14.7:1 most of the time. Except say over 80kpa manifold pressure. (Moderate to heavy load)
Closed loop with a good tune can run just as good as open loop. Its more consistent too because the fuel trims will keep it inline as the engine wears. Open loop will require a retune for each mod and as the engine wears the tune till not be quite bang on. If you have a tune tool and wideband, this isnt a problem. But for most people they will want to use closed loop.
Yes you get more features and functionality than an aftermarket setup for free. Well the cost of the tuning tool.
You can run 2bar or 3bar custom operating systems as well as change from the stock MAF based fueling to Speed Density (Mafless) or Alpha-n (TPS v RPM) based. Plus NOS, Valet mode, etc, etc.
You can run 2bar or 3bar custom operating systems as well as change from the stock MAF based fueling to Speed Density (Mafless) or Alpha-n (TPS v RPM) based. Plus NOS, Valet mode, etc, etc.
ringram said:
Some guys use 2, but 99% only use one. In open loop, when the car is under heavy throttle etc the PCM fuels both banks the same. So you can do one side which should be close to the other. Some guys also tune to one side, then swap the WB (wideband) over and check to make sure that there isnt any engine or exhaust issues.
I got mine off a place in Germany www.lm-1.com they are around £130 by the looks these days.
The LC1 for example and most others have 2 programable outputs, one for wideband and the other for narrowband. You can wire the narrow bands to the ECM using the stock connector if you want to replace one of the stock sensors, or you can create a new bung. The LC1 comes with a threaded bung to use. A new bung is probably the most ideal.
How many NB's does the LS2 have? example 2 maifold, 2 post cat? 2 on each bank.I got mine off a place in Germany www.lm-1.com they are around £130 by the looks these days.
The LC1 for example and most others have 2 programable outputs, one for wideband and the other for narrowband. You can wire the narrow bands to the ECM using the stock connector if you want to replace one of the stock sensors, or you can create a new bung. The LC1 comes with a threaded bung to use. A new bung is probably the most ideal.
Edited by ringram on Tuesday 27th February 17:08
I think i read on the efi forum that if you wanted to simulate NB you would nead two WB's. If there are two NB's, one each side at the manifolds, do I just replace them with the WB's wire the NB outpus to the LS2 PCM and the WB's outputs into the cockpit for use with Efi live?
You can get away with one WB if you leave other one as is.
I replaced one narrowband with a wideband, which has 2 outputs. You can run the narrow band back to the PCM as per usual and the wideband into the tune tool and off you go.
If you use 2, just repeat. You can take the 12V and GRND from the stock O2 cable, ideally get a spare connector and wire the wideband to just clip into the stock connector.
The hardcore guys use 2 widebands though. Its the sensors located before the cats that you want to replace. Any post cat are there to verify cat function (on us cars etc)
I replaced one narrowband with a wideband, which has 2 outputs. You can run the narrow band back to the PCM as per usual and the wideband into the tune tool and off you go.
If you use 2, just repeat. You can take the 12V and GRND from the stock O2 cable, ideally get a spare connector and wire the wideband to just clip into the stock connector.
The hardcore guys use 2 widebands though. Its the sensors located before the cats that you want to replace. Any post cat are there to verify cat function (on us cars etc)
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