Primera with ITBs

[G-man]

will be getting the car dynoed as is, in two weeks time, and will then start on getting the VEMS in and working... the dyno should hopefully give me a base showing how it is before going to VEMS.


re the air sensor, is there a specific place in the plenum I need to drill and tap to fit it, or is it a case of pick a spot and go for it...obvioulsy this will change later on once the ITBs come in to play...


also still concerned at how I am going to get the hi cams to come in, if there is no RPM feed going into the Vems.....

[rob@vems.co.uk]

will be getting the car dynoed as is, in two weeks time, and will then start on getting the VEMS in and working... the dyno should hopefully give me a base showing how it is before going to VEMS.

An excellent idea, nice to see that you're doing it properly, better than I did as I had no baseline to compare my improvements against!

re the air sensor, is there a specific place in the plenum I need to drill and tap to fit it, or is it a case of pick a spot and go for it...obvioulsy this will change later on once the ITBs come in to play...

Ideally it will be in the plenum near the throttle, sampling the air as its sucked in down into the engine, with the throttle bodies I positioned mine in between the trumpets for cylinders 2&3.

[/quote]also still concerned at how I am going to get the hi cams to come in, if there is no RPM feed going into the Vems.....[/quote]

The VEMS takes the CAS input and calculates engine speed and position to within a fraction of a percent, in the Extras->Misc Outputs you'll see that there are a couple of settings that can be used to switch a control channel, we'll need to figure out which channels you have free, there's one already set-up to control the VVT on the S14/S14a adaptor.  I don't see the pins to activate the solenoids on your pin-out table below though

[G-man]

there is no mention in the pinouts because the cams are not activated by the ecu, I'm using the Greddy MSS to activate the cams....

it is quite a simple thing to work, the solenoids are connected to it, and 1 wire from the MSS taps into RPM feed that goes into the ecu. when the revs go over a certain set limit it activates the solenoids accordingly to kick the cams in.....ECU basically has nothing to do with activating the cams, all that is left is for fueling and ignition timing to be mapped correctly within the ecu for when the cams activate...

hope that makes sense...

[rob@vems.co.uk]

there is no mention in the pinouts because the cams are not activated by the ecu, I'm using the Greddy MSS to activate the cams....

it is quite a simple thing to work, the solenoids are connected to it, and 1 wire from the MSS taps into RPM feed that goes into the ecu. when the revs go over a certain set limit it activates the solenoids accordingly to kick the cams in.....ECU basically has nothing to do with activating the cams, all that is left is for fueling and ignition timing to be mapped correctly within the ecu for when the cams activate...

hope that makes sense...

I'm guessing that the standard ECU had some control of the cams though?
The RPM feed comes out of the ECU, there will be a voltage on the tacho line (OEM ECU pin2) which is grounded through one of the VEMS pins, this should be the same signal as the Greddy MMS reads.
You will be able to remove the Greddy MMS and let VEMS do the switching if you so desire.

[G-man]

Yeah the ecu that came with the VE engine obviously did the switching job as well, though this was limited as it switched both cams on at the same time, at a set RPM...with the MSS you have the advantage of being to tune the best RPM to get the cams to come on, as well as having the ability to switch them individually....

at present my ecu is the standard non VE one, so it wouldn't have anything to do with cam switching....suppose if you could do the switching within vems and it was as flexible as the MSS re when and which to switch on first then yeah that could be the way as well..

[rob@vems.co.uk]

Ah, that's the key bit I was missing.
As you're not running boost or VVT there are two Injector FET channels that you can use to control the solenoids, can you can pick their switch-on and off point with Throttle and RPM position.

[G-man]

Ah, that's the key bit I was missing.
As you're not running boost or VVT there are two Injector FET channels that you can use to control the solenoids, can you can pick their switch-on and off point with Throttle and RPM position.

rpm is all that is needed, but yeah tps can be used as well

[G-man]

have a look at this....

http://www.sr20-forum.com/vvl/54-vvl-how-configure-greddy-mss.html#post353

may make things clearer

[rob@vems.co.uk]

rpm is all that is needed, but yeah tps can be used as well

I was talking from the perspective of the VEMS the Misc Outputs can be set at different RPM and/or TPS and/or MAP values.
As you're going to end up using AlphaN the MAP function will be redundant.

As for wiring it all up:

The yellow and green wires would go to two spare injector FETs
And the red wire would go to either the ECCS power supply, or from its current supply.

[G-man]

I was talking from the perspective of the VEMS the Misc Outputs can be set at different RPM and/or TPS and/or MAP values.
As you're going to end up using AlphaN the MAP function will be redundant.

being a total newbie when it comes to VEMS and tuning it, can ya explain a bit more about the above? I assume AlphaN is another software/way of tuning VEMS?
whats the implications of not having the MAP function?

[rob@vems.co.uk]

There are several ways of calculating engine load and its fuelling/ignition, we use either Speed Density - where the MAP pressure and RPM are fundamental in calculating the engine load, and AlphaN where throttle position and RPM are used (with correction for Temperature, barometric pressure and some other odds and ends).

Speed density is a great way to calculate load, but only when you have a clean vacuum or boost signal, when you get into lumpy cams, and throttle bodies vacuum signals get noisey and loose resolution, with ITBs you can't see much of a vacuum change between 50% and 95% throttle but the fuelling requirements are very different...  So throttle position is a better solution in these cases.

Rob

[G-man]

ahh ok, understand now, and funnily enough the contact I have in SA who is trailing the first set in a VE is using Gotech standalone EMS for his management, and he will be tuning by TPS and RPMS only as well...

[rob@vems.co.uk]

It really is the only way for ITBs, and works perfectly for normally aspirated engines.  The trouble comes when you try turbos with ITBs...

[G-man]

It really is the only way for ITBs, and works perfectly for normally aspirated engines.  The trouble comes when you try turbos with ITBs...

lol not a problem for me, as one modified turboed car is enough....its NA all the way with this one...

[G-man]

with the map function being totally redundant when going Alpha N, does it mean the Map sensor is now not needed, or is it still used to preform other functions? wonder if it could be used in some way to keep the PAS and AC working by kicking up idle speed when those two come into play.....