MS3X MPi Trials
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1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Edited by dan187 on 7th Mar, 2014.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

The 998 with the MPi manifold is my middle lads car. The MPi manifold is a temporary measure to get the car on the road. It will be fitted with the T2 and manifold from the 998Ti. Also a new design 350mm runner inlet manifold.

There's also my eldest lads car with the 1293 Gt2056 MS3X project and my own 998 Gt1752 MS3X project waiting in the wings.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Schrödinger's cat - so which one am I ???

The issue with the individual pulses was the short pulse widths at idle.

However, the MS3 has improved facilities to handle short pulse widths by inputting a curve when the injector characteristics are non-linear.

On my 998, I'm going to be sailing close to the wind with 600cc/min primaries and 1000cc/min secondaries if I use individual pulses.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

So I've been tuning the individual pulse system for the last couple of weeks. It drives a lot better than the overlapping pulse. I think the most noticeable thing is the throttle response is improved due to the shorter PWs required and the greater frequency of injection. It is much easier to tune too. I've been adjusting each injector with the trim tables. The biggest issue is the resolution of the tables. I could do with a couple more bins. On the whole though a much better drive. EGO correction seems to be doing a good job at correcting most errors. Image below shows the latest AFR results. left hand plot is the difference between the inners and outers and right hand is the error of outers from the AFR target table. You can see at high rpm full throttle i'm not able to get enough fuel into the outer without filling the inners with bucket loads of fuel. Hence why I need to crack on with the manifold. Hopefully get started next month on that.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

I know this won't help you but the MS2/Extra code should be noticeably better when using individual pulses since it has code dedicated specifically for it. I just want to point it out for anyone looking at this and thinking about doing the same.

First, you don't have to use multiple outputs on the same injector. Second, you have separate injection timing and fueling for the inner and outer cylinders so that each one can be optimized. That gives you a full resolution table for correcting fueling. On top of that you can use the trim tables which are also full size on MS2/Extra.

Of course, there are other features that are either only available on MS3 or more refined compared to MS2/Extra. But siamese port fuel injection is still better catered to on MS2/Extra. So you have to weigh those in when planning this type of project.

Jean

Edited by jbelanger on 28th Mar, 2014.

http://www.jbperf.com/

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

The fuel injection pumps are positive displacement, so you should be able to wind up the regulator to at least 5-6 bar before either the fuse blows or the pump fails.

If you can only get to 3.3 Bar, then the pump must be worn and flow is circulating within it and not building pressure at the regulator.

I'm assuming that your statement about the max that the MPi pump can provide means that you have tried to wind it higher.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...ME:LU:GB:3160

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

We've used the Walbro 255/Mpi conversion on the Mini 30.

Bit noisy, but more than up to the job.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

For what it's worth, on my old (now long gone) 16V K series Metro, the in-tank pump started to run erratically long before it should have failed.

I stripped it down (they are supposedly sealed units but you can bend the tangs back on the housing) and it was absolutely full of crud, mostly rust from inside the tank that gets attracted to the permenant magnets of the motor and fouls the armature.

All things being Leyland/Rover I'm with Paul, knackered pump.

I use an external one so easier to diagnose/change but, yes, try a new pump first.

The roller vane design they all use should be good for 10bar before the motor stalls and blows the fuse.

Schrödinger's cat - so which one am I ???

Got the Walbro 255 fitted... Paul you're a fantastic man! Problem solved, turned up fuel pressure and got 5 bar before I was more than convinced it was working.

I wound it back to 4 bar with no vac. Plugged vac back on and took it for a drive. AFR on the outers was instantly down to 13.5 at WOT at 5000 rpm.
So some injection timing tuning to do now to try and converge the AFRs past 3500 rpm.

Any recommendations on the pressure to set the rail at?
TurboDave did some work here: http://www.turbominis.co.uk/forums/index.php?p=vt&tid=9217
on small pw response of MPi injectors. Showing 5 bar was ok. However, if I plan to run 0.5 bar boost pressure that'll take my fuel pressure to 7.5 bar (1:1 rate regulator fitted). Is that too much?

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Most setups run at 3 Bar and this is the pressure used for measuring injector capacity in most cases. Some setups run 3.5 Bar but that's usually returnless setups.

Running more won't give you much unless you are running injectors that are too small and you want to increase the fueling. And if your injectors are large enough for the top end, increasing pressure will just make it more difficult to tune the low end.

Jean

http://www.jbperf.com/

Glad you got it sorted.

I always use 3 bar (no vac) as most injectors are designed for that.

Also 0.5 bar boost will add 0.5 bar to the pressure, not 50%, so no problem.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Dan, any updates?

Our 998 with MS3x and MPi inlet is running a treat, just need some fine tuning.

Then I may try the individual pulse method

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Hi Paul,

lovely, have you got the latest afr scatter plot?
It was quite quick to go from long pulse to dual pulse, only a small bit of timing change.


As for updates, not really... I've got it running reasonably well. Need to adjust for air temperature as i've noticed now the cooler weather is coming that it's rich most of the time. There are also a few spots in the map which are slightly out. But I just haven't had time to do much on it. Just been driving it. I got married in august and have been flat out working on Minivation bits so just getting back to having spare time now.

I hope to get my bespoke inlet manifold made and on the car before Christmas. so that will should be interesting once it's running.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Latest plot:



Only spent a couple of hours on it so far. Drives well apart from a very occasional loss of sync that I need to diagnose.

Still a bit to do but the lad has cleaned the car, put the cover on and moved onto doing his brothers 1293 Efi Turbo Racing Flame

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Hi Dan, Hi Paul,

I'm trying also a MS3 at a 1380ccm MPi with the original injectors full sequential. I have the injector timing at end of squirt. The Engine runs well until 5.000 rpm. I have some problems to find the correct timing at low rpm and high MAP, and high rpm and low MAP. Can you help me there? What difference you have between 100kPa and 35kpa at the same rpm? I'm at the moment at 650 deg at Idle and 540 deg at full throttle at 6.500 rpm.
My second problem is speed misfire at more than 5.300 rpm. I have Lost Sync Reason 22 - Rover#2 tooth error. Do you have any idea how to fix this?

Stefan

The standard injectors will not support the airflow of a 1380. I suggest you go a lot higher, say 800cc/min.

I use mid pulse timing, so cannot comment on the injection timing figures.

Have you switched on the noise filtering? this may help with the sync loss.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

End Pulse Timing is like mid puls +90 deg. I want to make sure, that the inner Inlet is closed, before start injecting the outer. Your values would be smaller by 90 degrees. I have a fuel pressure of 4.0 bar and set 500ccm per min. So I get a max PW of 4.6ms. At the moment, I have a max duty circle of 20%. But I also think it runs better with bigger injectors and less fuel pressure.
I have no idea what settings I have to do for the noise filtering. What values should I try?

(apologize my bad english)

Here two logs from the missfire

Attachments:

314.9kb

http://www.jbperf.com/