secondary injectors

[esprits4de]

The secondary injectors set in at about 4800-4900 RPM. I think that the power surge created through this is fairly abrupt.

Has anyone played aroung with reprogramming the ECU into having these set in at lower rpm or even played around with staging the injector output ?

[CarlC]

Looking at my freescan logs from last night my secondary injectors where coming in just under 5000 rpm and seem to also be dependant on the amount of throttle bring applied over 5000rpm. But I would not say I can notice when they come in but more that the car keeps pulling smoothly through the rev range.

Anyone else notice when the secondary injectors kick in. I didnt expect to be able to really feel when they did ?

[Artie]

Looking at my freescan logs from last night my secondary injectors where coming in just under 5000 rpm and seem to also be dependant on the amount of throttle bring applied over 5000rpm. But I would not say I can notice when they come in but more that the car keeps pulling smoothly through the rev range.

Anyone else notice when the secondary injectors kick in. I didnt expect to be able to really feel when they did ?

<{POST_SNAPBACK}>

I don't think I don't count but I have my secondaries stage in at 4K rpm and tip in is unnoticeable. There is power surge but it is quite linear(almost electric like power). I, if you have followed my saga, have a turbo model that I have chargecooled and added the secondaries with an electric injector controller. Hence the reason I don't count! Just chiming in that it is very nice adding in the the fuel from them at 4K.

Art

[karmavore]

Marcus' chips kick on the secondaries around 3K.

[Dermot]

Luke,

No quite true.

Secondary Injectors are controlled by a 3D map based on RPM and TPS

The base map is on

https://users.ox.ac.uk/~ohare/ecu_tables.htm

Best way to look at this in the Freescan log data is to plot Secondary Injector DC vs. RPM

PUK chips trigger secondary injectors just below 5000 rpm and initially it is quite gradual. This was an improvement introduced by Andy Whittaker.

Dermot

Dermot

[karmavore]

Humm... I have logs showing them kicking on much earlier. Let me look.

[karmavore]

Check out this log from my dyno page:

http://retrophit.com/Dyno/logs/run12_20050...pS4Sat45psi.xls

They seem to start to trickle at 3-3.5K

Lucas.

[Dermot]

Lucas,

Yes, I see what you mean. I think it is the special characteristics of the dyno. Thanks, I have not had a Freecan from a dyno run to study before. You were able to go WOT at 1000 rpm and hold it all the way to 7000 rpm. First secondary injector trigger occured at 3287 rpm and the boost was already about .8 bar.

Regards

Dermot

[esprits4de]

Check out this log from my dyno page:

http://retrophit.com/Dyno/logs/run12_20050...pS4Sat45psi.xls

They seem to start to trickle at 3-3.5K

Lucas.

<{POST_SNAPBACK}>

Lucas, what then makes them set in as early as this, just Markus' chip ?

[karmavore]

Would seem so, but I'm just deducing this from my logs on my car on the dyno. Lots of variables.

The logs I have using the OEM chip doesn't cause the 2ndaries to spit until, as Dermot said, until 5K.

[Paula&Marcus]

Lucas, what then makes them set in as early as this, just Markus' chip ?

<{POST_SNAPBACK}>

Hi All,

Yes the chips #4, #5 and #6 have the secondaries kick in earlier. Its also done by a 3D-map like with the stock chip. It just begins earlier and the fuelling is a bit richer, of course.

For example, with #6 the secndaries may kick in at 3200 rpm (only if MAP is high enough !)

Here is the 3D-graph:

I hope this will shed some light.

Cheers

Marcus

[islandbloke]

I think all this chip work rocks!

Years ago I raced a modified MG Midget and one winter we scratched our heads to think of another way of bending the rules (we'd already done splitters, a whaletail and a big bonnet scoop...all of which were subsequently banned) and my engine bloke (I'm useless with spanners) suggested we go for a properly mapped ignition.

Remember, this is only the sparks bit of the equation - no fuelling (carbs were mandatory). So he found an MBE system and bought a laptop and learned hex! He then devised a way to trigger the thing (a missing tooth on a modified crank pulley IIRC) and spent hours and hours with the car on his rolling road.

Certainly increased power, but more importantly, the car - which ran a wild race cam etc - was MUCH more driveable. Of course it was banned the following year...

Hats off to you guys.

[M Blur]

Not sure when my chip will kick in the secondaries - but at least the one in now will actually trigger the secondaries.

I'll keep an eye on it.. I guess they'll fire as soon as th ecar goes into overboost so I guess that is the key - Dermot/Marcus - can you elaborate on that..?

[Dermot]

As Marcus says it is linked to both boost and RPM. Most cars generate 0.8-1.0 bar boost just below 4000 rpm and this region is were most road cars trigger the secondaries.

Marcus I have question, since the ECU is still in closed loop as the secondaries start to trigger how does the ECU control the fueling. Are the primaries the controlling injectors and ECU just runs the secondaries of tables or are the BLM values applied to the duty cycles of both sets of injectors.

Dermot

[karmavore]

As Marcus says it is linked to both boost and RPM.  Most cars generate 0.8-1.0 bar boost just below 4000 rpm and this region is were most road cars trigger the secondaries.

You sure about that, Dermot? I think the 3-D graph above is for #6 Chip.

I have a log (again from the dyno) where, for example, RPM = 4028, Baro = .81, MAP = 1.92, and SI DC = 0

Marcus I have question,  since the ECU is still in closed loop as the secondaries start to trigger  how does the ECU control the fueling.  Are the primaries the controlling injectors and ECU just runs the secondaries of tables or are the BLM values applied to the duty cycles of both sets of injectors.

Dermot

<{POST_SNAPBACK}>

Good question.

[Dermot]

Luke,

How to visualise how the secondaries trigger on an actual car is hard to plot using just 2D (x,y) graphs. RPM vs Secondary DC is just a line though the 3D map. I have been trying to see if I can take Freescan data and use it to plot 3D graphs, a bit like the one Marcus has posted which comes from the chip programming software.

I believe the data is in the file as 3 variables to do it. I have tried doing it in Origin which is quiet a fancy maths plotting package but the data is just not the right format

for 3D plots.

So if anyone has any ideas I would be interested in some feedback.

Dermot

[karmavore]

No matter the number of axis you should be able to resolve a DC based on inputs for each axis. That was my attempt in the last post.

[Paula&Marcus]

As Marcus says it is linked to both boost and RPM. Most cars generate 0.8-1.0 bar boost just below 4000 rpm and this region is were most road cars trigger the secondaries.

Marcus I have question, since the ECU is still in closed loop as the secondaries start to trigger how does the ECU control the fueling. Are the primaries the controlling injectors and ECU just runs the secondaries of tables or are the BLM values applied to the duty cycles of both sets of injectors.

Dermot

Hi Dermot,

thats a very good question.

In most scenarios, when the secondaries kick in, you are actually in WOT (TPS>96%) and open loop mode.

For example, its very unlikely that you get nearly 1 bar boost @ 3000-4000 rpm without doing 100% TPS, ;o)

In other words the 3d-graph for the secondaries usually* is done in a way that it does not really interfere with the "normal" primaries closed loop fuelling.

Yes the primaries are the controlling injectors, the secondaries cannot get affected by the BLM-values. They just run according to their fixed 3D-graph.

If it really happens occasionally that the secondaries are "disturbing" the closed loop primaries work it is not a problem, because when it happens it will happen at a very low secondary DC cycle. The O2-sensor will detect this and will adjust your BLM value to a slightly lower level.

*With chip #7 or other special variants (on heavily modified engines with high output) we are intensionally using the secondaries also for normal fuelling purposes to help/add to the primaries in closed loop mode.

Of course, thats only useful with applications where the primaries max out (DC >80%) and the fuelling becomes a bit lean in normal closed loop operation. You will notice that effect looking at a wide band lamda sensor or just at your BLM-values.

The secondaries are a very handy tool to optimize fuelling. You have a real 3D-graph to play with and additionally you can also vary their size.

You see, the whole stock ECU is a very powerful engine management system. You have all the features you willl need to set up an engine properly in a very wide powerband ... no need for something different here ;o)

Unfortunately, many people who work on Esprits donot really understand how this entire management system is working. They just donot realize that the whole Boost Control->Fuelling->Timing->Thing is a dependent loop. They very often disturbe and totally confuse the whole system by adding unsuitable components (wrong MAP-sensors, wrong/too big injectors, wrong O2-sensors, wrong fuel-pressure-regulators, piggyback-confusion-boxes and so on and so on ...) with very poor results. Just swapping out a properly dimensioned component with not matching "bigger" part will not lead to a better result.

Cheers

Marcus

Edited July 26, 2006 by Paula&Marcus

[MrDangerUS]

On 7/26/2006 at 01:36, Paula&Marcus said:

 

Hi Dermot,

that's a very good question.

 

In most scenarios, when the secondaries kick in, you are actually in WOT (TPS>96%) and open loop mode.

For example, its very unlikely that you get nearly 1 bar boost @ 3000-4000 rpm without doing 100% TPS, ;o)

In other words the 3d-graph for the secondaries usually* is done in a way that it does not really interfere with the "normal" primaries closed loop fueling.

 

Yes the primaries are the controlling injectors, the secondaries cannot get affected by the BLM-values. They just run according to their fixed 3D-graph.

If it really happens occasionally that the secondaries are "disturbing" the closed loop primaries work it is not a problem, because when it happens it will happen at a very low secondary DC cycle. The O2-sensor will detect this and will adjust your BLM value to a slightly lower level.

 

*With chip #7 or other special variants (on heavily modified engines with high output) we are intentionally using the secondaries also for normal fueling purposes to help/add to the primaries in closed loop mode.

Of course, that's only useful with applications where the primaries max out (DC >80%) and the fueling becomes a bit lean in normal closed loop operation. You will notice that effect looking at a wide band lambda sensor or just at your BLM-values.

 

The secondaries are a very handy tool to optimize fuelling. You have a real 3D-graph to play with and additionally you can also vary their size.

 

You see, the whole stock ECU is a very powerful engine management system. You have all the features you will need to set up an engine properly in a very wide power band ... no need for something different here ;o)

 

Unfortunately, many people who work on Esprits donot really understand how this entire management system is working. They just donot realize that the whole Boost Control->Fueling->Timing->Thing is a dependent loop. They very often disturbe and totally confuse the whole system by adding unsuitable components (wrong MAP-sensors, wrong/too big injectors, wrong O2-sensors, wrong fuel-pressure-regulators, piggyback-confusion-boxes and so on and so on ...) with very poor results. Just swapping out a properly dimensioned component with not matching "bigger" part will not lead to a better result.

 

Cheers

Marcus

Marcus,

Could you tell me please, with your Red Racing chip (#6 ), when the secondaries kick in?

[Vulcan Grey]

Marcus hasn't been on here since 2010.