17 replies to this topic

[Woody]

Hi , does anyone on here know anything about the megasquirt fuel injection ?
I have been on the megasquirt site and it looks like the cheap answer to an expensive problem :grin:
I was thinking of useing a pair of motorbike throtle bodies
unfortunatly i have never done any electronics building before :sad: and find the idea of building my own ECU from a box of bits a bit daunting
Anyone tried this ?

[Pavel]

Why not just get a mini twin point injection set up? Should be very easy to find (i'm gonna keep my eyes out for one soon), since people keep trying to convert back to carbs from injection and just bin the whole thing.

Or are you going for a mad racer engine that the ECU and injectors won't cope with?

[AlexF2003]

Funnily enough....

Megasquirt is my latest project, hence the Monte I now have.

I have my kit on order and once I am happy it works in mini PROPERLY I plan to sell kits, built ecus and offer mapping.

What spec of engine are you going for... MPi is going to be much harder to get to work... if SPi will meet your requirements it would be much cheaper and easier to go that route!

Alex

[Wil_h]

I'm puting on on both my Minis. I've got all the parts needed, just waiting for the Squirt its self.

I'm only using it for the mapped ignition though, siamese ports and all that.

Wil

[Woody]

Pavel , why do you think all those people bin the standard injection set up ?

I am still in the planing stage and trying to find out what will work best , I am considering converting a 40DCOE webber into throtle bodies , or maybe using two motorcycle bodies , this was the route sergested when i disscust it with a firm that fitted weber alfatronic (was too expensive)
single point may be easier to build and set up , one of the mags have said it is possable to convert a SU to a throtle body (this would be good for under bonnet origionality).
as megasquirt has no ignition built in I am planing to use edis(think that is what its called )
any and all info on this project would be greatfully recieved .

[Rob]

Retro cars magazine covered this about 3 or 4 issues ago. It lookes very good. I will be using this so I can do away with the distributor and fit a front mounted rad.

[siggy]

It looks very iinteresting. But what advantage would you have over carbs?

Personally it looks very expensive, How much is the kit and does this include all the sensors, air flow, TPS ect? How much time would you expect to spend building it and getting it running correctly. Time being the most expensive part of the build.

I would not have the electronic knowedge to be confident enough to build one or more importantly the time,

Siggy

PS good luck to thoses who go that route

[AlexF2003]

It looks very iinteresting. But what advantage would you have over carbs?

Personally it looks very expensive, How much is the kit and does this include all the sensors, air flow, TPS ect? How much time would you expect to spend building it and getting it running correctly. Time being the most expensive part of the build.

I would not have the electronic knowedge to be confident enough to build one or more importantly the time,

Siggy

PS good luck to thoses who go that route

The advantage over carbs is the MUCH better control of the air fuel ratio, which if you combine with proper spark control means in theory you could run a 286 cam in a road engine and it would drive fine on the road!!

It is expensive but there are ways to keep the costs down.

Time is the huge issue, there has been very very little development for minis on the injection front other than the "replace all that electronic stuff with a carb" nonsence!

To build a megasquirt ECU is suppose to take about 4-5 hours the 1st time you do it. Then there is the all the time to install it and get it working!

The reason I brough my Cooper Monte is to develop a plug in kit that works in minis as an easy solution for anyone who either has injection, or who wants to play with it.

Alex

[Pavel]

Alex do you think you could write a quick rundown about the installation of a megasquirt into a mini? I've been reading up on the whole thing and seems quite good. However:

Do you plan on using one injector into the inlet? Which would you use?
Are you going to buy all the bits that are needed from DigiKey/megasquirt so that you just put it all together without going around everywhere trying to find tiny components?
Where are you getting all the sensors and which ones are you going to be using etc.?

Just a basic idea of how you plan on getting this to work on a mini engine since I am now rather interested in this whole thing, and I'm sure many people would be!

[AlexF2003]

I'll give it a go but I haven't got very far into the project yet...

The plan so far is:

Using a std SPi manifold and all associated sensors the std Rover MEMS system used. The reasoning behind this is to create a replacement mappable ECU for modified injection minis that simply plugs into the std loom.

Next I will repeat the above but with a MPi engine (oh good another mini I need to buy!!).

After these two cars I will have good base maps to be able to offer other injection solutions, such as converted SUs/webers or Jenvey Throttle Bodies.

I also hope to offer kits so people over here don't have to worry about DigiKey... but in the mean time the best place to get them seems to be:

http://www.glensgarage.com/

Alex

[Woody]

Well , this is a project for early next year , hope to have it running smoothly before the Nurburgring run :grin:

[siggy]

I can not see any point in using single point injection, as the inherent problem with an single carb is the 2 outer cylinders running weak, hence scatter cams. No injection system will overcome this.

IIRC the heads on injection cars are differnt to carb ones?

When fords changed the escorts from the K jetronic to efi they had terrible running problems, they tried changind it but never managed to cure them. I was told by Ford technical, that this was because they never developed the cylinder head to suit the change.

Siggy

[AlexF2003]

Charge robbing is not a problem of the fuel injection system or carb.. its down to the fact the head has 5 ports and a firing order of 1,3,4,2

The heads are the same no redesign needed.

SPi is still better than a carb as you have better fueling control at all throttle positions and engine loads, not a guess like carbs are!

"When fords changed the escorts from the K jetronic to efi they had terrible running problems, they tried changind it but never managed to cure them. I was told by Ford technical, that this was because they never developed the cylinder head to suit the change."

Which engine are you talking about?

Alex

[Woody]

Ok , from what i understand it goes like this (please corect me where apropriete)
you need a large venturi (i think thats the right word for it )for big HP but a large carb works C**p at low engine speed because of low vacuum does not atomise the fuel very well , this is made even worse if you have a cam with large overlap,, now with injection fuel delivery is not dependant on air speed at all so you can have your large throtle bodies (for big air flow) and a perfect mixture even from very low revs with a cold engine under heavy load
try puting your foot to the boards at low revs with a 40 dcoe and a big cam and all you will do is get it to spit back and set fire to your air filter !
and not only that , but the increase in mpg means it should pay for itself

[Dan]

Injection systems can go some way to curing charge robbing depending on how the pulses are grouped. Sometimes you can alter the timing for the 1 and 4 pulse slightly so that the fuel is only injected once the gas flow is on it's way to the correct cylinder (this as I understand it was the real stumbling block when Rover changed to the MPi system but they cured it eventually). Since you can alter the fueling point for different groups of cylinders like this you can pretty much get the effect of a scatter cam without the shocks to the crank that changing the valve timing for different cylinders can cause. It is a tricky balance however as the fuel obviously needs more time to reach the outer cylinders than the inners which also needs to be taken into account.
AFAIK the only changes to the heads for injection involved different bracketry for accessories and ports for sensors. The combustion chamber and porting is pretty much unchanged.
You still don't want a really massive throttle body, just one that's big enough.