Apexi AVC-R / RICA fuel mapping

[mulletboy2]

Hiya guys,

I've read that the engine internals of Nookie should be good for around 350bhp. What I'm wondering is whether I could just increase the boost using an Apexi AVC-R (variable actuator controller), or whether there's anything else important that needs to be thought about first, such as is RICA mapped for the higher boost/fuel levels? What level of boost is she good for?

Not that I'll necessarily increase the boost anyway, but it's always nice to know what options are available. The AVC-R does so much more than just increasing the boost (graduate the onset of boost in 1st/2nd/3rd so you can have one setting for wet, one for dry etc...), but if I install it and know it's safe to play, I might just do that.

Cheers

Mark

[Mrsmopp]

Nookie boosts quite happily to 1.2bar, the RICA has reworked the way she thinks and she fuels etc accordingly. The problem with fitting a V.A.C is that if for any reason she needs to run on limp home mode the V.A.C will bypass this and she will be unable to run in safe mode. It isn't recommended that you fit MBC's or anything similar after an ECU upgrade.

x

[mulletboy2]

Mrsmopp - thanks for the info Do you know why the limp home mode wouldn't work? Is it something to do with the RICA remap?

The reason I ask is because I know that the Rover still worked fine in limp home mode after having the Apexi fitted, as I accidentally triggered it by not re-connecting one of the connections to the ECU properly (might have been the MAF sensor pipe, but I can't remember for sure) after doing some work on it. However, I'm fully aware that I don't know the slightest thing about Nookie yet, so just curious as to how she thinks

Cheers

Mark

[volvotuning]

If you override the stock boost control with an aftermarket one, then the RICA (or stock) ECU cannot lower the boost in limp-home. In fact it can't control the boost due to excessive intake temps either. So although the car is in limp-home, the boost level could still be way to high for safe limp-home.

It's nothing to do with RICA, as the limp home is not even messed with. For most reliable and safe running, the ECU should have direct control of the boost, especially if you are unsure of what you are doing when tuning.

Adam.

[mulletboy2]

Cheers Adam I'm still a little confused though. I don't understand how this works, so please forgive me if I'm flogging a dead horse. What you've explained - would this be the case with all cars? What kind of damage is it likely to cause? It's pretty obvious when a car's in limp home mode, so it's unlikely that anyone would try to use boost more than once or twice before deciding something's wrong. I understand that use of these things is rarely recommended, but regarding overriding (or ignoring) limp home mode is a new one on me.

Cheers

Mark

[volvotuning]

No, it's not the case for all cars, especially on much older cars where boost was not electronically controlled. However, from the 850 T5 onwards, the boost is controlled electronically using it's own electronic boost controller. To explain in a bit more detail...

Limp home is what the manufacturer has determined is the safe running parameters for running the engine in order to get you home. It's different for various manufacturers. For the Volvo T5, limp home is a preset value for max boost, fueling levels and ignition timing. Do not confuse limp home with emissions faults (lambda light).

So when a T5 goes into limp home, the ECU wants to lower the boost to about 0.5 bar (7 psi). However if you have replaced the standard boost controller with an aftermarket boost controller which is not controlled by the ECU, then proper limp-home cannot be achieved.

But that's just limp home. On the ME7 ECU cars, the ECU also tries to lower the boost to a safer level when conditions are adverse enough, such as too much heat. Again in this case, overriding the ECU controlled boost is not a good idea because the boost has been lowered for safety.

Adam.

[Mrsmopp]

Adam whilst we are on the subject of limp home mode - under what conditions do these cars run on limp home? i.e. What faults would determine that the ecu decides limp home is needed?

x

[volvotuning]

Well, the answer is loads of conditions!!! Could be faulty throttle, could be an overboost, could be a fueling issue, could be so many things!!!

Adam.

[mulletboy2]

Adam - thanks for the more detailed explanation. I think I understand now So it sounds like this isn't the right way to go, which is fair enough. Can you just confirm though (to make sure I am understanding things correctly) that even if the Apexi has taken over controlling the boost, rather than the ECU, the mixture would still not end up being lean if the Apexi was boosting too high when in limp mode, as the lambda and MAP sensor would re-adjust the mixture correctly... i.e there's no danger of incorrect fueling, but whatever has caused the ECU to go into limp mode would still be an issue?

Call me a tart, but I love the Apexi display, so I think that the way forward may be to install it and get it to take the various readings from the ECU, but not let it control anything, that way there'll be no danger of things going pear shaped

Cheers

Mark

[volvotuning]

Mark,

I'm afraid I can't confirm that because the fueling at full throttle may be wrong if you do what you say. See, the ECU will adjust fueling automatically, but only at part throttle as it uses the closed loop lambda reading for fueling. But at full throttle it only uses the fuel mapping and does not care about the lambda reading. How far out the fueling may be, I don't actually know. It may still be within tolerance in which case it will be ok.

In limp home, it doesn't use the MAF sensor values, so you could very well be running super lean if you are boosting too high in limp home.

Adam.

Can you just confirm though (to make sure I am understanding things correctly) that even if the Apexi has taken over controlling the boost, rather than the ECU, the mixture would still not end up being lean if the Apexi was boosting too high when in limp mode, as the lambda and MAP sensor would re-adjust the mixture correctly... i.e there's no danger of incorrect fueling, but whatever has caused the ECU to go into limp mode would still be an issue?

Mark

[mulletboy2]

Adam - good point, thanks for that

[Bracer]

If you want to increase boost, the only real way to do it is through the ECU, all other ways just try and trick / overide what the ECU wants to do.

And Psi for Psi you will get more power out of a Mapped ECU than just a Boost Controller

Steve

[mulletboy2]

Cheers Bracer Nookie already has a mapped ECU, so I was just wondering whether I could use the Apexi to safely get a bit more power, but clearly the answer to that is "no".

I do still love the apexi though, for the digital RPM, duty and boost guages/graphs/digital displays... I could still hook one up to take readings without actually controlling anything, or making it any less safe, and after looking at her lastnight with respect to fitting my stereo, it looks like with a bit of work, one would fit inside the ashtray, which could be opened/closed as required when parking up - nice an stealth, and still get the display I'd like. Also, I'm guessing that a spare ashtray would be easy enough to source, so that nothing is damaged beyond repair

Cheers

Mark

[BlackBeast]

What would you do if you wanted to run 2 boost settings, 1 for economy say 0.8bar and then 1 for spirited driving at 1.2bar for example?

[After_Shock]

black beast the ecu's can have two different modes on them and just switch between as and when its needed.

With regards to the boost controllers yeah they look nice however have one major problem, when the boost is increased their will always be the problem of fuel as it doesnt increase this, its o.k if only increasing it slightly but not when increasing it a good bit as the car starts running lean.

Sorry if something similar has been said as I havent read all of the thread!

[mulletboy2]

Sorry if something similar has been said as I havent read all of the thread!

It has The fuel must be mapped up to whatever level you want to run at.. if it's not, whacking the boost pressure up is going to do nothing but cost you a lot of money.

[After_Shock]

The Nissan people seem to get away with it just by adding an uprated fuel pump and whacking the boost up, but then again when not hammering it the cars run rich!

Can also get the fuel adjuster aswell to match the boost controller, would look very nice built into a dash side by side! Not sure if a T5's ecu would allow the fuel to be overriden though.

[BlackBeast]

The Nissan people seem to get away with it just by adding an uprated fuel pump and whacking the boost up, but then again when not hammering it the cars run rich!

Why would they be running rich!?! Adding an uprated fuel pump does not change a cars fuel pressure at the rail, the reason why they change the pump is because its a safety precaution when using higher boost as they dont want to run lean!

[After_Shock]

Im just saying what I got told, I havnt done the mod on my nissan but people have told me that would need both the boost and fuelling controller otherwise would run rich in normal situations.

If the fuel pump is adding more pressure on the fuel line surely it would affect that at the rail also? Otherwise whats the point in doing the mod as a safety precaution if it doesnt allow more fuel through at the rail?

[Pedro Fandango]

i thought there was a pressure regulator on the fuel rail