Inlet upgrade?

Fast Eddie said:
90hp 961...?
Sorry, my mistake I didn’t realise we were talking about superchargers... ;)
Click to expand...
I'm determined to be optimistic.
If I said 82HP, who would bother. :cool:
I'm putting the supercharger on hold, until a practical nuclear fusion power station is a reality.
In other words, there is no hope of one in this century.
 
Still interested in a proper electric turbo style supercharger. Even Garrett are working on them. Gives you a short boost when you need it from a lipo pack which recharges while pottering along in traffic. Haven't done the maths but like the idea.

Ref inlet mods my pre-mod dyno run showed the bike running lean (see other thread) so the shop recommended not to do anything to possibly lean it off until I either get a new richer map installed or new fiddleable ECU otherwise no benefit and possible damage. Anyone enlighten me to what maps are available from a dealer who has access to the hidden mysteries of the Euro 4 Omex ECU?

But as the Omex ECU is a Lambda closed loop system how can inlet mods lean it off further? I feel like what should be a logical process is muddied up with a dose of Black Arts carried over from the days of swapping carb jets and distributor advance springs and bob weights.....
 
Clive said:
Still interested in a proper electric turbo style supercharger. Even Garrett are working on them. Gives you a short boost when you need it from a lipo pack which recharges while pottering along in traffic. Haven't done the maths but like the idea.

Ref inlet mods my pre-mod dyno run showed the bike running lean (see other thread) so the shop recommended not to do anything to possibly lean it off until I either get a new richer map installed or new fiddleable ECU otherwise no benefit and possible damage. Anyone enlighten me to what maps are available from a dealer who has access to the hidden mysteries of the Euro 4 Omex ECU?

But as the Omex ECU is a Lambda closed loop system how can inlet mods lean it off further? I feel like what should be a logical process is muddied up with a dose of Black Arts carried over from the days of swapping carb jets and distributor advance springs and bob weights.....
Click to expand...
My (very limited) understanding is that the ECU can only compensate within a relatively small range. That range is designed to cope with weather, altitude, etc... not tuning.

Clearly your ECU is already making it run on the weak side. I think the point is that if you weaken things further, the ECU may not have the range to compensate for this.

Hence, you’ll get no benefits, and may get damage.
 
I’ll have to look at what kind of lambda sensors the 961 runs, but I can add some general info. Narrow band sensors ( which I think the 961 has) typically have, as the name suggests, a very narrow band of operation, so could be used to compensate for small variations. They are typically used to tune the mixture at small throttle openings and idle. They typically won’t be used throughout the Rev range and even not all the time, even at idle. At these times, the ‘map’ both ignition and fuelling is used. When you start from cold, the sensors need to warm up. Newer ‘wide band’ sensors are typically electrically heated to help bring them up to optimal operating temps sooner, but older narrow minds need more time...so while they are warming up, you are probably running on a map. The need to be at a certain temp is why they are placed nearer the engine vs the tail pipe. Off idle and under hard acceleration, this is another area where you would probably be running on the map, where you’d be running richer than stoichiometric ideal....14.7:1....you’ll probably run richer than that in most points in the Rev range. When you fit factory open exhausts is an example where you want to run a different map. As the ecu is probably not running closed loop at the point where the pipes make a difference...the ecu doesn’t know you are running lean, as it’s well into the area where you are running a map, independant of lambda readings....and you are outside the area of accuracy of the narrow band sensor anyway. .....so closed loop doesn’t mean closed loop all the time. Mostly it isn’t running closed loop....but for idle and emission testing ( which there is no current requirement for bikes in the uk post homologation) it will be. Newer ecu’s ..maybe the delta..would need to check, can use wide band sensors. These can operate at a far great range vs narrow bands, so can be used to ‘tune’ the engine at any speed. Some of the US based ecu companieies make ‘E Z efi’ systems where the ecu tunes itself using wide band sensors. This will keep you safe...lean at low revs load is relatively safe, but high loads, higher revs and lean conditions will melt pistons. There is still no substitute for a mapping session on a rolling road, where both ignition and fuel maps can be optimised for power, so the map becomes the desired settings and the wide band sensors can help keep the fueling at these desired points...but I know on my home brewed efi set up on my car, I’m running the map most of the time....but I can configure what parameters determine the closed loop vs open loop operation...below x revs at x throttle opening below x temp, run closed loop. That sort of thing. On the 961, changing anything that effects ( improve really) the efficiency/ airflow through the engine will effect fueling as more than likely, where they have the most significant effect when you are running ‘on the map’ and fueling is not being tweaked by the ecu. Outside the ecu using closed loop, the ecu is effectively ‘blind’ it sees Revs and throttle opening and makes it’s fueling decisions based on it’s look up table. It’s still mind boggling about how quickly this is all done. I have a 30-1 trigger wheel on the front of my engine. 30 teeth, one gap. The ecu counts the teeth, can ‘see’ the gap....it knows the gaps is at 40 degrees before top dead centre....then thinks, ok, I know the revs, so I need to fire the coils 10 degrees before tdc, so need to wait while crank turns another 30 degrees....while I’m waiting, I’ll go and check the fueling map, see what injector duration I need....all up up to 6500 rpm. With a bike, it could be looking at 13 k rpm or higher. You just can’t imagine the speed theses things work at!
 
Vernon240 said:
... Newer ecu’s ..maybe the delta..would need to check, can use wide band sensors. These can operate at a far great range vs narrow bands, so can be used to ‘tune’ the engine at any speed....
Click to expand...

The Delta 400 can use wide band sensors, as well as narrow band sensors. In SCS' words, it has "Stereo Closed Loop Fuelling Control (Narrowband or Wideband) with Lambda Auto Mapping."

Ken
 

Attachments

lcrken said:
The Delta 400 can use wide band sensors, as well as narrow band sensors. In SCS' words, it has "Stereo Closed Loop Fuelling Control (Narrowband or Wideband) with Lambda Auto Mapping."

Ken
Click to expand...
Cool, wonder how effective automapping is? Pretty sure wideband vs narrow band wiring is different, so would take some work to add a pair.....but not impossible. I’ll have to have a look at the manual. One system I used needed a programmable controller that mapped afr ratios across a 0-5v output. Never really got it to work accurately. Might dust it off and take another look.
 
Vernon240 said:
Cool, wonder how effective automapping is? Pretty sure wideband vs narrow band wiring is different, so would take some work to add a pair.....but not impossible. I’ll have to have a look at the manual. One system I used needed a programmable controller that mapped afr ratios across a 0-5v output. Never really got it to work accurately. Might dust it off and take another look.
Click to expand...

Right. It does require a wideband controller to use wideband sensors. SCS sells them for 90 pounds each. I've thought about trying them out with my D400, but so far haven't convinced myself that I really need them. On the 961 it would also require either welding in new fittings or using adapters to accomodate the larger thread diameter of the wideband sensors. I have fitted wideband sensors to my 961 using adpaters, but have so far only used them with a stand-alone WEGO controller and data logger to collect AFR data.

Ken
 
Probably a good idea to clear up the topic of o2 sensors and open vs. closed loop.

A narrow band o2 sensor can only tell the ECU the engine is rich or lean relative to lambda 1 (lambda being the ratio of air to fuel that results in complete combustion (gasoline is 14.7:1, methanol is 6.46:1 etc), a lambda value less than 1 is rich more is lean - it functions as part of a closed loop control circuit that in effect means the ECU is constantly swinging the mixture from slightly rich to slightly lean. You don't need to know the actual AFR number in this type of circuit (look up PID controllers if you want to know more), to rich or to lean is all you need. These systems don't cope well with sudden big changes in inputs i.e. opening the throttle, but are very efficient in steady state conditions. A narrow band o2 sensor has by definition a narrower range of operation but this doesn't matter if the initial fuel values programmed into the ECU are reasonably accurate. Also as it can only say the AFR is rich or lean relative to lambda 1 it's useless when the engine requires a richer (or leaner) mixture since it has no idea what the actual value is (not quite true but the ECU is only looking for a rich or lean signal as a narrow band can't read values outside a narrow range).

A wide band sensor has a wider range of measurement and can provide the actual AFR number to the ECU. But there is no need to fit such a sensor in a mass produced engine. Instead you place an example of the engine on a dyno, fit it with a wide band o2 sensor and program the ECU with the correct fuel values at different load and RPM values. If done correctly the engine should be receiving the correct fueling at any combination of RPM and throttle position. The proviso being that the engine including induction and exhaust system is the same as when the engine was on the dyno. This is called an open loop system, there is no feedback to the ECU regarding the actual AFR, but since there is no loop there is no delay and the ECU can instantly change the fueling on the fly. If done correctly there is little benefit from a manufacturers perspective in fitting a wide band o2 sensor as they're much more expensive than a narrow band sensor.

Obviously once you start modifying any part of the engine including induction and exhaust you will start to see changes in the AFR when in open loop. In closed loop things will generally remain the same (if the modifications are not to extreme) as the ECU is able to detect the change and compensate via the input from the narrow band o2 sensor.

But you need to bear in mind that power is not directly made by changing the AFR. The ultimate name of the game is to produce the maximum amount of pressure on top of the piston at precisely the right point in its stroke. Most engines are knock limited meaning you cannot achieve the optimum ignition timing without encountering knock. Knock is essentially the uncontrolled ignition of fuel often caused by excessive cylinder temperatures. If you add fuel you might think you get a bigger bang but this is not what happens! That extra fuel does not burn instead it acts to lower the cylinder temperature which then allows you add more timing. This is why you see flames coming out exhausts - it's the excess fuel suddenly being exposed to oxygen and is now able to burn. It has not been used to produce any power in the cylinder its only function was to cool the cylinder to allow more ignition advance.

Simply speaking there are only two ways to make more power.
  • Get more air into the cylinder to make a bigger bang and
  • Adjust the ignition timing to achieve peak cylinder pressure at the correct point in the pistons stroke.
So we only add fuel in excess of 14.7:1 to control cylinder temperatures so we can add more ignition advance. Obviously there's a whole lot more going on but I hope this makes some sense. High octane fuel for example resists knock allowing for more ignition advance - don't bother paying the extra for it if your engine doesn't have a knock sensor and an ECU able to automatically adjust the timing to take advantage.

Vernon240 said:
Cool, wonder how effective automapping is? Pretty sure wideband vs narrow band wiring is different, so would take some work to add a pair.....but not impossible. I’ll have to have a look at the manual. One system I used needed a programmable controller that mapped afr ratios across a 0-5v output. Never really got it to work accurately. Might dust it off and take another look.
Click to expand...
It would not be capable of getting close to what could be achieved on a dyno. On a dyno you hold the engine at a fixed RPM and slowly change the timing and fueling at each load point (throttle position) to achieve peak torque (the dyno holds the engine at a fixed RPM regardless of throttle position). A good operator will use an anti-knock system to get the engine safety to this point.

If you start mucking around with a modern engine without the ability to program the ECU you can easily end up in a world of hurt! For example, you manage to get a bit more air into the engine playing around with the intake or exhaust system. Great you think, but without changing the fuel tables you now have an engine running lean with the potential to knock!
 
Last edited:
iwilson said:
If you start mucking around with a modern engine without the ability to program the ECU you can easily end up in a world of hurt! For example, you manage to get a bit more air into the engine playing around with the intake or exhaust system. Great you think, but without changing the fuel tables you now have an engine running lean with the potential to knock!
Click to expand...
Thanks for this great info but I think you sent Nigel's brain open loop ;). So is the answer a knock sensor? Looking at the Omex site it looks like it is possible to add a knock sensor but again we are into the realms of a DIY dabbler trying to program an ECU which I have come to the conclusion of being very difficult. I'm thinking if I manage to get the bike running on the dyno with a AFR reading that looks ok, which should be possible thanks to open loop mode, and I'm not too worried about economy - more preserving the engine - then I should not be too far from getting the best from the engine. First 'dabble' is a pair of alternative higher flow injectors.

I think back to when I was at Lucas with the mechanical fuel injection systems on cars such as the TR6 which were crude in the extreme but economy and fuel emissions were not such big considerations.
 
iwilson said:
Probably a good idea to clear up the topic of o2 sensors and open vs. closed loop.

A narrow band o2 sensor can only tell the ECU the engine is rich or lean relative to lambda 1 (lambda being the ratio of air to fuel that results in complete combustion (gasoline is 14.7:1, methanol is 6.46:1 etc), a lambda value less than 1 is rich more is lean - it functions as part of a closed loop control circuit that in effect means the ECU is constantly swinging the mixture from slightly rich to slightly lean. You don't need to know the actual AFR number in this type of circuit (look up PID controllers if you want to know more), to rich or to lean is all you need. These systems don't cope well with sudden big changes in inputs i.e. opening the throttle, but are very efficient in steady state conditions. A narrow band o2 sensor has by definition a narrower range of operation but this doesn't matter if the initial fuel values programmed into the ECU are reasonably accurate. Also as it can only say the AFR is rich or lean relative to lambda 1 it's useless when the engine requires a richer (or leaner) mixture since it has no idea what the actual value is (not quite true but the ECU is only looking for a rich or lean signal as a narrow band can't read values outside a narrow range).

A wide band sensor has a wider range of measurement and can provide the actual AFR number to the ECU. But there is no need to fit such a sensor in a mass produced engine. Instead you place an example of the engine on a dyno, fit it with a wide band o2 sensor and program the ECU with the correct fuel values at different load and RPM values. If done correctly the engine should be receiving the correct fueling at any combination of RPM and throttle position. The proviso being that the engine including induction and exhaust system is the same as when the engine was on the dyno. This is called an open loop system, there is no feedback to the ECU regarding the actual AFR, but since there is no loop there is no delay and the ECU can instantly change the fueling on the fly. If done correctly there is little benefit from a manufacturers perspective in fitting a wide band o2 sensor as they're much more expensive than a narrow band sensor.

Obviously once you start modifying any part of the engine including induction and exhaust you will start to see changes in the AFR when in open loop. In closed loop things will generally remain the same (if the modifications are not to extreme) as the ECU is able to detect the change and compensate via the input from the narrow band o2 sensor.

But you need to bear in mind that power is not directly made by changing the AFR. The ultimate name of the game is to produce the maximum amount of pressure on top of the piston at precisely the right point in its stroke. Most engines are knock limited meaning you cannot achieve the optimum ignition timing without encountering knock. Knock is essentially the uncontrolled ignition of fuel often caused by excessive cylinder temperatures. If you add fuel you might think you get a bigger bang but this is not what happens! That extra fuel does not burn instead it acts to lower the cylinder temperature which then allows you add more timing. This is why you see flames coming out exhausts - it's the excess fuel suddenly being exposed to oxygen and is now able to burn. It has not been used to produce any power in the cylinder its only function was to cool the cylinder to allow more ignition advance.

Simply speaking there are only two ways to make more power.
  • Get more air into the cylinder to make a bigger bang and
  • Adjust the ignition timing to achieve peak cylinder pressure at the correct point in the pistons stroke.
So we only add fuel in excess of 14.7:1 to control cylinder temperatures so we can add more ignition advance. Obviously there's a whole lot more going on but I hope this makes some sense. High octane fuel for example resists knock allowing for more ignition advance - don't bother paying the extra for it if your engine doesn't have a knock sensor and an ECU able to automatically adjust the timing to take advantage.


It would not be capable of getting close to what could be achieved on a dyno. On a dyno you hold the engine at a fixed RPM and slowly change the timing and fueling at each load point (throttle position) to achieve peak torque (the dyno holds the engine at a fixed RPM regardless of throttle position). A good operator will use an anti-knock system to get the engine safety to this point.

If you start mucking around with a modern engine without the ability to program the ECU you can easily end up in a world of hurt! For example, you manage to get a bit more air into the engine playing around with the intake or exhaust system. Great you think, but without changing the fuel tables you now have an engine running lean with the potential to knock!
Click to expand...
There are quite a few of these 'self tune' systems out there. 'FAST' have one and they claim it tunes as you drive, but agree, hard to see how it optimises things other than just keeping things safe. Mind you. I bought one of their trigger wheels. What a piece of crap. Way too thin and would not run true. It now hangs on my wall of shame of the many failed parts. Still the sensor pick up worked. Once I modified it to fit!
 
Clive said:
Thanks for this great info but I think you sent Nigel's brain open loop ;). So is the answer a knock sensor? Looking at the Omex site it looks like it is possible to add a knock sensor but again we are into the realms of a DIY dabbler trying to program an ECU which I have come to the conclusion of being very difficult. I'm thinking if I manage to get the bike running on the dyno with a AFR reading that looks ok, which should be possible thanks to open loop mode, and I'm not too worried about economy - more preserving the engine - then I should not be too far from getting the best from the engine. First 'dabble' is a pair of alternative higher flow injectors.

I think back to when I was at Lucas with the mechanical fuel injection systems on cars such as the TR6 which were crude in the extreme but economy and fuel emissions were not such big considerations.
Click to expand...
Could that be the simple answer? Following inlet and exhaust mods, if found running weak, tweak the injector? Would the O2 sensors look after idle and low revs allowing extra fuel were necessary up through the revs? Or is my thinking locked in a carburettor tuning loop.
 
Al's#5 said:
Could that be the simple answer? Following inlet and exhaust mods, if found running weak, tweak the injector? Would the O2 sensors look after idle and low revs allowing extra fuel were necessary up through the revs? Or is my thinking locked in a carburettor tuning loop.
Click to expand...
Open loop works in our favour here so I'll let you know - my baseline dyno chart is in another thread. I'm going up around 10% flow rate and will try them with the standard airbox, then with the K&N intake filters.
 
Al's#5 said:
Could that be the simple answer? Following inlet and exhaust mods, if found running weak, tweak the injector? Would the O2 sensors look after idle and low revs allowing extra fuel were necessary up through the revs? Or is my thinking locked in a carburettor tuning loop.
Click to expand...
Not really...well, maybe, but not a path I would go down. Yep, you are thinking in a carb type tuning mode! You would tweak idle jets, mains, emulsion tubes..accelerator pumps cams, secondary springs if you like your Holleys etc to try and get the fueling right under all conditions..idel, off idle, agressive acceleration, steady state..then you might try different springs/weights on your dizzy to alter the ignition curve.

When you start changing injectors as a means of tuning, you are kinda harking back to changing jets etc, wheras the whole idea on EFI is you don't need to do this. You could play around with jets all day long. They were relatively inexpensive and nothing was really lost. When you start playing around with injectors as if they were jets, just to see what happens, it starts to get pretty expensive. I know a fair amount about this stuff, but I'd be simply making an educated guess as to what would work....and then have to write off a couple of injectors and try again if it wasn't what I wanted.
You could tweak the fuel rail pressure (the ECU is simply opening the injector for a specific duration, not a specific amount of fuel....that comes when you combine a fixed pressure and a specific duration which will give you a specific amount of fuel..but the ECU won't know anything about your pressure) but that means more fuel is delivered everywhere across the rev range. An adjustable regulator MIGHT give you some tweakability and if I wanted to play without biting the new ECU bullet, I might investigate this. Changing injectors would probably not feature, as after a few different injectors, I'd soon be heading towards an ECU cost.

Once example of when I have changed injectors was when I was new to all this. Bought throttle bodies from the US and asked for the suggested injectors for my application. No problem they said. Turns out they were waaay to big. Even reducing my line pressure, I could not actually get the injector duration low enough to get my mixture anywhere near right at moderate to low engine speeds (it was fine wide open!) These things were throwing fuel in by the bucket load it seemed. So I bought new smaller (in terms of flow rate) injectors and now I had adjustability.

Normally you might entertain upgrading injectors as far as flow is concerned if you were on a dyno, max revs and your injector is close to 100% duration and you are still weak. so you are 'running out of injector' You could up line pressure, which can work, or look at new higher flow injectors. Changing pressure while mapping can cause an issue, but there are tricks around this...but you may well end up repeating the process if you started from low to high revs.

I recon Iwilson has played around with the Norton 961 more than most in this regard, so I'd listen carefully, as he seems to have a fair few miles under his belt on this specific subject.
 

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