MS1 upgrade to MS2

[Chris_rx8]

Is this upgrade a simple plug in my MS1 is modified to run Edis, I will only be using it for controlling 3 ITB's and spark through the Edis on a straight 6 engine, I might convert at a later date to run this direct for ignition at a later date but I would like to get it running on this setup ASAP.

One other question which is the better system to use Alpha N or speed density when using this type of setup

many thanks I advance

[rickb794]

You may run up against an issue with the Siamese'd intake ports.

[BlackBird_SR71]

What engine is this?

I'm assuming the 3 ITB's are like twin choke Webers or Mikuni's. So there may be no siamesed ports. Can't even think of va straight 6 that uses Siamesed ports. Maybe an old Pontiac OHC engine... but those are as rare as Hen's teeth.

[BlackBird_SR71]

MS2 has a specific Fuel Algorithm for ITB's. That may be your best Option.

2.13.1 Control Algorithm choice
There are a number of different methods to estimate the airflow into an engine. These depend on the
available sensors and their accuracy at predicting flow.
Use Speed-density unless you have a good reason to choose otherwise.
At the most basic level:

• Speed Density uses the MAP (Manifold Absolute Pressure) sensor to determine load. In this case,
the vertical axis of any fuel table lookups is in kilopascals (kPa). The maximum value reported by the
MAP sensor (in non-turbo applications) will be the same as the barometric pressure.
Relatively easy to configure, works on boosted engines and familiar to most tuners.

• Alpha-N uses the TPS (throttle)
Can be a poor estimator of airflow. Useful is a MAP signal is unavailable or unreliable.
Be sure to calibrate the throttle range using Tools->Calibrate TPS before using this setting.
• MAF uses an actual mass air-flow sensor and related calculations to directly determine the amount
of fuel to inject. In this mode, the VE table is not usually used to determine the amount of fuel to
inject.

• ITB uses a combination of MAP and TPS
This mode was created specifically for naturally aspirated engines running with independent throttle
bodies. It combines alpha-n (at high engine loads) with speed density (at low engine loads), using
the load calculation that makes the most sense at each RPM. For example, most ITB set-ups do not
have good vacuum at idle or low RPM, and slightly touching the throttle makes them lose all
vacuum, but at higher RPM start to respond more like a traditional single throttle body engine. This
mode allows the use of speed density set-ups at low engine loads and switches to alpha-n at high
loads, with an adjustable switchpoint curve over RPM.

• %baro uses a combination of MAP and a barometer reading.
This setting is similar to the Speed Density setting in that the MAP sensor is used to determine load.
However, instead of directly using the manifold pressure, the manifold pressure is divided by
barometric pressure to give a percentage of barometric pressure. This setting can be useful for those
who regularly drive at high altitudes. It ensures that regardless of barometric pressure, all table
lookups operate over 0-100%. For example, if barometric pressure is 80kPa, and the engine is
operating at 50kPa, the actual value used for table lookups is 50kPa/80kPa or 62.5%.
All have pros and cons. Radical engines may need to use a combination of algorithms. Many engines will get
good results with Speed Density or MAF.

[DaveEFI]

Is this upgrade a simple plug in my MS1 is modified to run Edis, I will only be using it for controlling 3 ITB's and spark through the Edis on a straight 6 engine, I might convert at a later date to run this direct for ignition at a later date but I would like to get it running on this setup ASAP.

One other question which is the better system to use Alpha N or speed density when using this type of setup

many thanks I advance

If it's a V3 PCB, a simple plug in job. If you wish to use the stepper motor chip on the MS2, you'll need to add a 12v link on the PCB. But note if you do this you can't put the MS1 chip back in without removing that link - the 12v will fry the MS1.

[Chris_rx8]

thanks for all responses
its on a Jag 4.2 6 cyl engine
3 ITB's onto a jag manifold so one butterfly for 2 cylinders

As my daughterboard was previously in a MS2 do I need to change firmware to make it work? can the firmware be upgraded afterwards through TS or do I still need to follow the firmware installation process if I can do this from TS again it will make the process very easy, im sure it will be as otherwise upgrading would be more clunky

thanks

[retired]

3 ITB's onto a jag manifold so one butterfly for 2 cylinders

I thought those engines normally had twin carbs, one carb for three cylinders ???

I've also seen a converted one with six LPG throttle bodies and one with three twin choke webers so one butterfly per cylinder in both those cases.

If the firing order is the usual 1-5-3-6-2-4 for a straight six, then one carb (or ITB) for the front three cylinders and another for the rear three works because the induction order is symmetric, ie, 1, pause, 3, pause, 2, pause, 1, pause, etc but if you switch to single carbs/ITBs for pairs of cylinders you get, 1, pause, pause, pause, 2, pause, 1, pause, pause, pause, 2, etc and so on, ie, not symmetric. That is one of the problems with any siamese ported engine, a typical 4 cylinder being 2, 1, pause, pause, 2, 1, pause, etc.
It's far worse on a 4 cylinder because inlet valve openings overlap. But if your firing order is 1-5-3-6-2-4 you will still be getting irregular flow down the ITBs and that has always been the fundamental issue with charge robbing as fuel and air accelerate at different rates due to the massive density difference. So, although it's not a siamese port as such, you may be making it work like one.

If your firing order is different to what I'm assuming, ignore me.....

[DaveEFI]

Jaguar used a plenum and port injection on the later XK EFI engines - XJ6 S3. The XK engine had two or three carbs depending on application. For a road vehicle, I'd be inclined to use the plenum. Much easier to map too.

[BlackBird_SR71]

Edit: Went away to answer phone while typing.... and DaveEFI beat me to it. LOL.

Jag 4.2 Inline sixes came in various Carb and intake manifold combinations. But all the Cylinder heads had six individual Intake ports.

The Higher spec engines used three carbs with a a twin runner manifold per carb feeding two cylinders. So with EFI you would have six individual Port injectors.

Lower spec engines use only 2 carbs with each carb feeding 3 Intake runners. But still six individual Intake ports. Similar to a Datsun 240 Z twin SU setup.

Jag 4.2 Liter with triple SU's:

Jag Su's.jpg (185.65 KiB) Viewed 424 times

[BlackBird_SR71]

To OP. There are companies that make Twin Choke ITB manifolds ( Jenvey comes to mind ) for Jag engines. Now that would be a nice way to go... but $$$$

I think Ort injectors would have less problem with the asymmetric port pulsing than carbs. But the Triple SU's work very well as is . Several Datsun 240Z owners have switched the 240Z Twin SU's to Jag Triple SU's and noticed a considerable gain in power. Not as much as Triple twin choke side drafts though.

[retired]

I think Ort injectors would have less problem with the asymmetric port pulsing than carbs. But the Triple SU's work very well as is .

I certainly wasn't aware of the triple SU version - so I apologies for my lack of knowledge there - but the asymetric ports are something I'm quite familiar with, with true siamese.
The thing to bear in mind with anything remotely "siamese" in nature is that injection does not behave the same way as carbs.
Carbs mix the fuel/air in a pretty uniform manner, especially if it's a long way before the inlet runners/port. A carb, esp. the SU design, is pretty much constant flow.
Injection does a number of pulses per engine cycle which may or may not be related to the air flow dependent on the timing of the pulses relative to the valve openings.
If the injectors are close to the valves, that timing is critical. Hence why jean wrote the MS2-E siamese sequential code for those of us using it on a 4 cylinder siamese engine so we can set the timing(s) to match the valves.
Those running injection on A series siamese engines with TBI have also had some good results, BUT, in all the cases I know of, just a single TBI so just like a single carb across all 4 cylinders - uniform mixing so potentially overcoming the asymetry of the two individual siamese ports if that makes sense.

So, in this case, my experience may not be that relevant, but when it comes to injection and asymetric port pulsing..... be aware....

If you inject individual pulses into an airstream that is asymetric without timing it, you may get some un-expected results.

But that's only assuming you measure individual cylinder AFRs, otherwise you may not know.