Greddy emanage tricked into open loop

Davegtst · March 30, 2015, 14:35

I've been doing a lot of research into piggy back ecu's like my emanage blue and have come to the conclusion they aren't that great when used with cars that aren't meant to have turbos. They work fine when the ecu is in open loop and not using the o2 sensors but there is quite a lot of time when the turbo is boosting but the ecu is still in closed loop so the tuning done on a rolling road is wasted and can lead to completely wrong fuelling. There is a product by a company called Split Second that fools the ecu into open loop as soon as positive boost is detected but it fairly expensive. I have come up with a plan.

It seems the TPS is only used to tell the ecu that power is requested and then puts the ecu into open loop. If I were able to get a pressure sensor and set it so it switches a circuit on at positive boost which in turn sends a wide open throttle signal to the ecu this should trick the ecu into open loop and allow the emanage to work properly.

What do you think? Have I missed something?

https://splitsec.com/product/lsc1-001-universal-fuel-enrichment-module/

ChrisGB · March 30, 2015, 15:41

You need to find a mapper who understands this and generates a map that works around the closed loop areas. Richard at Redline tuning does a decent job of it, no issues fueling for 10psi of boost on my old system and it is running nicely in its new home too.

If your pressure triggered switch tells the ECU that you are at WOT, the ECU won't be correctly timing and fueling for the actual throttle condition. Remember adding a turbo changes the fueling and timing requirements at many load states between zero and peak boost.

Davegtst · March 30, 2015, 16:15

But does the tps actually change the timing and fueling. From what I've read it doesn't.

Davegtst · March 30, 2015, 16:53

Just done a quick test with another tps plugged and not connected to the throttle. With the engine at idle and turning the tps to full it doesn't change the ignition timing but does put it into open loop which changes the fueling to what the emanage is set to.

I can't see how a re map would change the closed loop areas. Surly the fuel trims would always be trying to adjust the mixture to keep it at stoichiometric.

ChrisGB · March 30, 2015, 23:48

If only it where that simple. Firstly, the splitsec does not put the ECU into open loop, it seems it tells the ECU that the target mixture is achieved by altering the O2 sensor readings so that the ECU does not adjust trims.

The TPS is the sensor that tells the ECU the load requested by the driver. If you tell the ECU that there is a fixed load, say 100%, the ECU will provide a fixed amount of fuel and timing for each RPM band, but that may well be way outside what a piggyback can realistically adjust for. Effectively, you would need a standalone to map from that starting point, one with its own accurate TPS or MAP sensor so it knows the load request.

From what I have seen, mappers who know what they are doing will monitor where closed loop activity is taking place and not apply piggyback correction in these areas. The stock ECU runs open loop enough of the time that you can successfully map for boost as many have done over the years.

If the mapper gets it wrong however, the stock ECU imposes some pretty crude across the board trims which will lead to rough running. Done right, the results are perfectly OK. I had a turbo setup controlled by a Unichip piggyback and Unichip electronic boost controller. It fuelled nicely under load allowing me to run 10psi, but have part throttle cruise efficiency in closed loop far better than pre turbo.

lamcote · March 31, 2015, 08:24

Regarding your first paragraph when you say the ECU is not put in open loop, I don't understand what the difference is between the ECU not adjusting trims, as you say, and running open loop. Don't these actually mean the exactly same thing, that being that the engine is indeed running open loop?
Thanks

ChrisGB · March 31, 2015, 08:32

Quote from: "lamcote"Regarding your first paragraph when you say the ECU is not put in open loop, I don't understand what the difference is between the ECU not adjusting trims, as you say, and running open loop. Don't these actually mean the exactly same thing, that being that the engine is indeed running open loop?
Thanks

The ECU is still running in open loop, but the splitsec is telling the ECU that the fuelling is hitting the target value, so it is not trying to trim fueling. It will still be providing a target fuel level based on load index, but effectively modified. Timing under partial load will still be related to throttle position.

Also remember, if you put the ECU in to WOT mode, you will also lose some vvti functionality.

hami · March 31, 2015, 09:32

I'm using the Splitsec Enricher for more than a year now, and it feels like I had a different car. Without the enricher the ECU lean the AFR back to 14.9 if you drive under 4000 RPM or 65% throttle position - you can really feel it, and it's not healthy either for a turbocharged engine. After it was installed the accelaration became smoother and harder in every RPM range, the AFR is in optimal range all the time. Now,my consumption is about 15 % higher in the city, but it's definetely worth the money! It's like a factory turbocharged MR2 now, I love it.

lamcote · March 31, 2015, 10:10

So do I take it that the ECU normally runs in closed loop below 4000rpm or less than 65% throttle.

Above these figures presmuably the ECU runs in open loop and can use modified settings put into the base map (load index?) by the tuner.

Below this the splitsec allows the ECU to read the load index directly, without any trims being added by the ECU based on the O2 sensors?

If the above is correct, two questions;

Can the settings in the load index, in the closed loop region, then be modifed by the tuner?
If yes to this, how do you pass the MOT?

Thanks

hami · March 31, 2015, 10:33

I can't remember how it works exactly, but the enricher has to be tuned seperatly I think. It's not that simple, that you install and it works fine. You can read about the setup here: https://splitsec.com/wp-content/uploads/datasheets/Enricher_ds.pdf . I don't live in England, don't know what is measured at the MOT, but probably it wont pass it with the enricher.

lamcote · March 31, 2015, 10:59

This is probably a massive over simplification but it seems the Greddy is used to remap the ECU running in open loop and the splitsec is used to remap the ECU when it is running the closed loop. Presumably the Greddy doesn't have the capability to trick the ECU in closed loop so without the Splitsec you are stuck at lambda =1 once closed loop kicks in?

Perhaps you can switch the splitsec off for the MOT?

Davegtst · March 31, 2015, 11:39

From what I can see the split second enricher will only fool the stock ecu when on boost so the mot won't be a problem. Most of the closed loop fuel trims will still work as normal.
The emanage can change the fueling across the range but in closed loop mode the O2 sensor will adjust it back to where it needs to be for good emissions. Open loop mode gets no feedback from the O2 sensor so it doesn't change the fueling.

lamcote · March 31, 2015, 11:45

Thanks everyone, it's all clever stuff.

ChrisGB · March 31, 2015, 14:14

The splitsec unit looks pretty useful. I wonder if any piggyback unit is available that could duplicate the function by altering the O2 sensor readings on their way back to the ECU?

Having said that, with multiple units all doing their own part, a standalone looks increasingly attractive.

lamcote · March 31, 2015, 14:50

But don't you lose OBD2 with a standalone. Also is the imobiliser, or anything else affected?

ChrisGB · March 31, 2015, 16:26

Quote from: "lamcote"But don't you lose OBD2 with a standalone. Also is the imobiliser, or anything else affected?

Yes, you get other challenges with a standalone. Some have their own diagnostic facilities, some don't, immobiliser needs to be run separately. You can also have issues driving the rev counter, temp guage, possibly charging circuit details too. It's never just easy.

Glubux · April 1, 2015, 19:42

Quote from: "Davegtst"It seems the TPS is only used to tell the ecu that power is requested and then puts the ecu into open loop. If I were able to get a pressure sensor and set it so it switches a circuit on at positive boost which in turn sends a wide open throttle signal to the ecu this should trick the ecu into open loop and allow the emanage to work properly.

That's how my car run, and it works pretty well!

1zz, turbo, E-manage blue with boost sensor, a relay, a voltage reducer.

It was not my idea, I came accros this :

First you have to know your WOT voltage, mine is 3.93v, set your voltage reducer to match this voltage

Drive a relay using the Vtec output of the E-manage, and try to use the mini Vtec map in order to drive the relay everytime the boost sensor sees boost, this ways it connect your voltage reducer to the ECU, and it switch to open loop and let you add all the fuel you want.

You can check the open/close loop with an OBD scan and Torque (Android)

Davegtst · April 1, 2015, 20:43

Your picture doesn't work. How to you set the vtec output?

Glubux · April 1, 2015, 21:11

Quote from: "Davegtst"Your picture doesn't work. How to you set the vtec output?

The picture came from here m http://www.rs25.com/forums/f72/191271-f ... age-2.html m

When the relay is off, the TPS is connected to the ECU, as normal.
When the relay is on, the voltage reducer (set with the same voltage as WOT) is connected to the ECU instead of the TPS

You drive the relay with the mini Vtec map, you can't change the "On/Off" inside the map but you can change RPM (horizontal), and you can choose "boost sensor" (vertical)

Then choose what RPM and what boost you want the relay to switch, mine is set at 0.05 PSI and 1500rpm if I remember correctly.

Davegtst · April 1, 2015, 21:31

Thanks for the link. Have you noticed any ill effects?

Anonymous · April 1, 2015, 21:36

Yes the pic is correct, the pic is of the pins of a twin pole switching relay. Got a few kicking about if needed

Glubux · April 2, 2015, 14:46

Quote from: "Davegtst"Thanks for the link. Have you noticed any ill effects?

The only side effect is with small turbos (I had a TD035 from a Subaru Forester, now I have a TD04 from a WRX).
With this kind of turbos, you can build boost with very partial throttle, like 20%. In this case your signal switch from 20% to 100% instantly, you can feel it, like a little kick. But when you hit boost with more throttle, the transition is smooth.

Davegtst · April 3, 2015, 20:09

Do you need to change the jumper settings to get the vtec output to work?

Glubux · April 4, 2015, 11:57

Quote from: "Davegtst"Do you need to change the jumper settings to get the vtec output to work?

I guess you don't have to change, the involved jumper is the n°3. It should be set to 2/3
The only reason to set it to 1/2 is if you have a second MAF (like a RB26) So it is none of our concern (yeah I should open mine to check but I'm a bit lazy today...)

Davegtst · April 29, 2015, 21:32

I've now built a circuit that switches from the real tps voltage to wide open throttle voltage. It's switched via the vtec output on the emanage and switches on at just over 0 psi and over 2200 rpm. What a difference it makes! It pulls so much more smoothly now and feels a lot more powerful, even holds boost more precisely. All emanage owners need to do this! Your rolling road tune is wasted without one.