eaton supercharger and mpi
Turbo Mini Forums

hi there am currently building an eaton powered mpi am going to utilise the original manifold with 2 injectors on then fit a third injector in the plenum for when it comes up on boost using a 52mm throttle jenvey throttle body the engine spec is as follows
stage 4 turbo head with large ports and valves
300 degree camshaft
36-1 pulley wheel with vr sensor
standard rover coil pack
megasuirt2
i know with this set up problems with the injector pulse will be encountered that is why i thought using the third injector would hopefully solve this as the main problem is injector pulse time

can anyone see any problems that i may have overlooked

thats a lot of cam for a forced induction engine.

it is the avonbar phase 3 turbo cam just under 300 degrees

do a search for phase 2 and phase 3,

the general view is the ph3 isn't worth it except maybe for circuit racing.

Hi,
I don't think the cam duration matters as much on a blower compared to a turbo?
Cheers,
Gavin :)

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Actually, the injector pulse time is not the main problem. The injector timing is, unless you're planning on keeping the standard ECU and only controlling the third injector with the MS2. If you want to control all the injectors with Megasquirt then you'll have a problem with injector timing even if you can get enough fuel from the injectors.

If you want Megasquirt-only control, you could either run with 2 injectors in the TB and none of the original ones. Or you could wait for the siamese-port code I've written to be fully ready and use only port injection. You'll then probably need either larger injectors in the ports or 2 injectors per ports depending on the boost you'll run. The 3 injector configuration will not be supported.

Jean

http://www.jbperf.com/

already had the camshaft as was gonna do a turbo conversion but as all project cars they do get alittle more exotic as time goes on

if i only use 2 injectors with your code then they will have to be very big and then they will cause other probs what is your recommendations are there any other management packages out there that will support what i want
was hoping to use the 2 port injectors to help smooth the effects of the bigger camshaft profile

That's why I developed the code: there is nothing out there available that can be used with the siamese ports.

How much power are you expecting from this setup? Some people are using very big injectors and can still get a decent idle. That's not ideal and will be tricky to tune. You could get a 2:1 rising rate fuel regulator which would help but you have to make sure that the pump will be able to flow enough at higher pressure. And that may bring other tuning issues.

There's going to be a few people working on all these issues soon with testing the code on turbo engines with different configurations. Unfortunately, there's no easy recipe to follow yet for a successful combination.

Jean

http://www.jbperf.com/

Jean, am I correct that your code will work with staged injectors using the staging control in the normal Extra code? If so you could run 2 small injectors in the standard position to deal with the idle and low level running and the larger ones to cope with high boost etc.

Or have I gone mad???

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

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

Roger,

You're right about the staging in the code so 2 injectors (one small, one big) per inlet port will work fine. At small loads only the small injector is fired and then at a certain point in the load range (user selectable) the second injector comes online still with one pulse per rev.

The problem with the 3 injector setup is that the third injector is in the plenum which means it sees all cylinders. This injector would need to be fired 4 times per cycle (or twice per rev) for to fuel all cylinders correctly. Since the code only does 1 pulse per rev, it's possible that some cylinders will not have their share of fuel from the third injector.

Port injection and TBI have different injection timing requirements to work correctly. Port injection pulse timing is critical which is not the case with TBI. TBI requires 4 pulses per cycle but it's not critical to time the pulses because they average out.

Jean

http://www.jbperf.com/

Jean,

that is what I thought ... 2 pairs of injectors staged.

I'd not give time to 3 injector set-up for the reason you state ..... not saying that there is anything wrong with trying these things, just that from what I know that it's never going to be the optimum solution!

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

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

yeh i understand the timing of the injectors on the port is critical and that the siamesed ports are difficult with 2 injectors cos of the injector firing order. but could the megasquirt be used set up as 4 injector sequential then splice together the outputs for injectors 1/2 with diodes so current only flows one way to injector 1 and 3/4 spliced together for injector 2 is this possible thanks

Hi,
The diode thing may work, but if a diode packs up it'll make a horrible mess of your ECU. Also it still doesn't solve the injection timing issue :(
Cheers,
Gavin :)

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WB/EGT gauges. Click here for customers write-up

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My Mini build diary