Eaton M24 Supercharger on SPI
Turbo Mini Forums

minimiglia0, I had thinks about such things, and the simplest way I found if you still use the standard system is ONE big injector before the s/c, drive by a MF2. But you will need to pay attention at the ignition, don't focus only on fuel system.
Matty, the camshaft sensor is used not to read the camshaft speed but to know when the 1st cylinder is in the 3rd stroke, in order to time correctly the injection (and ignition on COP system).
If you don't have such sensor, the engin don't know if your #1 cylinder that is on the good phase or if it's your #4.

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

Ah I see, never thought of that. So a secondary sensor would also need to be fitted with MS aswell?

Has anyone got any examples of the secondary sensor fitted?

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

It's only needed if you plan to run port injection, but for a SPI, it work without that!

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

VEMS will run sequential port injection without the secondary trigger (edit, uses Ion sense, of which i dont understand yet). However, when we look at the Mini MPi system, its a little more complicated.

Cam sensor usualy gives information as to when the inlet valve is on its opening ramp, so that the injector squirts fuel when there is air moving into the cylinder, carrying the fuel, rather than the fuel sitting on a closed valve. This improves the fuel distribution and reduces port wetting

VEMS runs sequential injection. When i say sequential, it fires only one injector at a time, on the port that is about to draw. The injectors fire at the same time as ignition, but at tdc, the difference is that the injector sequense is reversed in relation to the ignition. IE number 1 cylinder on combustion/ ignition stroke, number 4 cylinder on induction/ injection stroke. The ECU then traverses through the sequence until its back to the top.

another way of describing it, ignition firing order is 4,2,1,3, so the injector firing order is 3,1,2,4

The injectors are infinately configurable, Batch fire, semi sequential and sequential from i right the way through to 8, 16 even if you double up!!!. If you had idnividual coils (coil on plug??) as well you can do the same with the ignition and have sequential ignition.

Edited by Sprocket on 25th Sep, 2007.

Hi,
Cam sensor is factory fitted on the MPi, I can't find a pic at the mo....
Gavin :)

Edited by Bat on 25th Sep, 2007.

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My Mini build diary

I don't know a lot about ion sense, but i've learn that it is the reading of the voltage at the spark plug when it is fired. To make a spark in the air, you must reach a voltage called (in english) something like air ioning, or air ionisation (in french: ionisation de l'air). This voltage is different if you have an atmospheric pressure (during overlap, piston at the TDC) or if you're in the combustion strike (still at the TDC, but high pressure due to the combustion stroke).
The ecu read the "break voltage" on both coils, and learn where is the 1st cylinder.

I've learn that it needs wasted spark system, but not sure.

Sorry if the explanations are poor... I will try to find something in good english

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

Ion sensing can be made to work but for 90% of applications can be easily fitted with cam position sensor which is more reliable, hence why most major manufactures choose it.

Edited by RogerM on 25th Sep, 2007.

Every day is a school day ...........

How fast and how expensive ...... the same question...

I've found that:
________________________
SAE Technical Papers

Title: Ion-Gap Sense in Misfire Detection, Knock, and Engine Control
Document Number: 950004

Author(s):
John Auzins - Delco Electronics
Hasse Johannsson - Mecel
Jan Nydomt - Mecel

Abstract:
The combustion of fuel inside an engine cylinder produces ions. By applying a small DC voltage across the spark gap after ignition, ion current is produced. The ion current wave form contains combustion information and is called Ion-Gap sense. Ion-Gap sense is described and can be used to detect misfire, control knock, obtain cam phasing, and detect pre-ignition. In the future, it will provide air/fuel information.
__________________________

You can also do your own cam sensor if you use a static electronic (or optical) distibutor, by cuting branchs on the star on a VR type sensor.

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

Another easy option is to use hall effect and mount a small magnet on the cam drive pulley.


I have read that paper, John Auzins is well known on the subject of spark ignition systems within Delco. He's a very clever chap I have had the pleasure of meeting once at a seminar on future combustion technology I was also presenting at.

IIRC the last part, about AFR only applies with direct injection.

Also IIRC there is a fairly precise requirement on the plugs too ... not sure you could do it with a good old fashioned plug with any accuracy .... well not at normal Mini type gaps. I could be wrong on that though.

Every day is a school day ...........

How fast and how expensive ...... the same question...

(Please, What does IIRC stand for?)

I agree that good spark plugs are a must.

I had some probs with my last car a Ford Taunus (a LHD Cortina mk5). Some times it works fine, and the other times my Pinto engine had only 3 cylinders. After checking the valves, cylinders pressure, seals betwenn manifolds, carbs, etc...,spak plugs, wires, dist...NOTHING.
A short time after, I bought a new set of plug,(the older were NGK, the newer were...NGK too). After the change, no more probs... For fun, I test the plugs continuity with my DVM, and one was discontinued. Sometimes the spark was strong enough to "skip" two gaps, and sometimes not... So imagine reading the phase of an engine with that kind of sh...

lol

----------------------------------

I continue to discover the Vems website, and some possible features make me smiles, but why not!

http://www.vems.hu/wiki/index.php?page=Oth...NintendoGameBoy

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

IIRC equals if I remember correctly

Thanks miniminor, I have some problem with these "sign". It take me a week to understand ASAP

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

Sorry Thigre ..... just used to web shorthand now ...

Every day is a school day ...........

How fast and how expensive ...... the same question...

LoL it doesn't matter! If I don't undertand, I ask!

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

Hi!
I still don't know what system (Vems or MS) I will use, but there are two "problems":

* 1st, the flywheel has a TDC and a BDC missing teeth, and booth ECUs run with M-N teeth per rev, and not 2x(M-N)...The read RPM would be twice the true one, no?
* 2nd, the IAC stepper of the SPI is a unipolar stepper motor, and both ecu run only bipolar. I've seen that Mini Sprocket has archeive to mods the original stepper to run as a unipolar one, but does it work?

I am "drawing" a trigger signal modifyer, that will cheat on the signal to correct the RPM (but it will still need a dist). I am also looking after controlling the unipolar motor without modifying the TBI unit. The stepper driver used in VEMS (I don't have a look into the MS one) can drive either unipolar and bipolar motor.. But I don't find all the informations about doing that (with hardware, not by modifying the code). Anyone has an idea, please??



I know it is stupid, but I really want to run the engine as the MEMS does before going a step further.

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

Just two picts for the 2nd step.

Thierry

Attachments:

26.53kb

26.37kb

Edited by Thigre on 4th Oct, 2007.

Mini British Open II 1275 SPI Full Stock
working on SSpi project

Stepper motor not a problem, needs slight modification, Stepper valve is the same, but just a little more difficult to get into it to modify, but I worked out a way round that anyway.

I have all the config data you would need to get the stepper to run on VEMS, its not complictated.

As for the crank trigger, you could use the SPi flywheel and weld on another tooth to the reluctor ring, would work a treat. I can give you the information if you want to go this route, however, you could also just fit an after market crank trigger kit.

Hope that helps

Edited by Sprocket on 4th Oct, 2007.

HI, I have some news:

I've just received my M24 blower (not as new as described by the the seller, but usable). The pulley has a diametre of 54mm. , the compact design of the unit will allow me to put it under the alternator and maybe directly after go into an intercooler.

I will not keep the original SPI manifold and TBI. I have found a rc51 TBI with two 500cc injectors, the fuel atomisation won't be as good but this will solve the fuel regulator problem.

There are some questions that needs to be solve, I hope someone can help me.

What's the MPI poly-V crank pulley diametre?
What kind of manifold should I use?
I was thinking about the MS large torquemaster or a built-by-myself like a standard injection plenum but running wet. This is a pic (not at scale, and not a definitive designe, but should give some ideas)
I was thinking about the tunnel ram manifold on V8, not very useful on supercharged engines, but it could help to mix the mixture well. (but, what about economy and efficience?)

I will take ALL advices, thanks

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

Bonjour,

My understanding is that with a forced induction engine the intake system design does not matter alot, unless you try to reach high (say >100HP/L with 2v/cyl) performances. Compressors make you spend more power than turbos, so increasing the boost by 1psi to compensate intake loses would not hurt much the overall performance.

Could you tell if your M24 has a clutch or a bypass ? The one I've tried to buy (VW FSI) did not seem to have any (like old Eatons/Lynholms), which would mean you'd need a throttle ahead the compressor. Not easy with a TBI injection.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

Nothing :)

Edited by alpa on 25th Nov, 2007.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

Salut!

No, i doesn't have any bypass or clutch. It would work with a recirculating valve or a an open air one just before the throttle. I am looking for some schems of the TFSI setup.

Mini British Open II 1275 SPI Full Stock
working on SSpi project

Screw compressors do compress the air all the time. The only way to avoid useless work is to feed them with vacuum. Or bypass/clutch them.

My remark about TBI was related to the injection BEFORE the compressor. I'm not sure Eaton was designed to work in a wet setup.

Edited by alpa on 26th Nov, 2007.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

Ok, sorry. I don't think it too, but it can (like the Vmax/jonspeed/moss).
The recirculating valve act like the built-in bypass found on the m45 and higher. you take compress air and return it before the charger, which received more, and draw less.

I 've read that you own a torquemaster manifold, don't you? Is it possible to grind the carb side to a 53mm bore?

Thierry

Mini British Open II 1275 SPI Full Stock
working on SSpi project

I have a Eaton M24 supercharger for my sons 998 Mini 30.

We are only going for moderate boost, say 7.5 psi and maybe 90hp.

I am planning to mount the M24 in front the engine with an intercooler.

Downstream of the supercharger will be a bypass valve that will recirculate back to the inlet under part throttle conditions.

This will then feed a standard MPi inlet controlled by Megasquirt.

I'm concerned about the lack of a plenum.

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."

I may be wrong but I believe a screw compressor always compresses the air. If you give it an already compressed air it will compress it more. The flow will decrease and you'll get the same mass flow, but you'll lose energy. It's different from a root or a centrifugal (turbo) compressors which won't do work without load.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm