Today is Pizza and Corona day. However we cheaped out and only had Pizza but while enjoying some of the best pepperoni and sausage in the NW, we stumbled across an idea that might work very well for stock ECU lovers.

You need to run 8 injectors on the stock ECU but dont want a piggyback?

Simple run 2 ECUs.

Wires tap all the major sensors needed (crank, cam, water, IAT, Baro, etc.) and run the additional 4 injector outputs. Ignition is left unhooked as well as the majority of the other senors that would throw a CEL and we'll just leave off.

Requires an additional OBD2 and jack but other than that it seems pretty flawless.

So this is where you guys come in...shoot the idea down and tell me why it wont work.

I can run my car on a stock ECU with no MAFT Pro now (thanks to John) on factory speed density or even with a stock MAF if I wanted. This gives me 4 extra injector inputs. Any Evo ECU could be used, and I would surmise 98+ Eclipse. Possibly even some of the other lesser cars that we wouldnt normally consider but if we are just hijacking an ECU who cares.

Discuss

 

Hey Aaron this is Chris the one that called you this afternoon asking advice on the E85 and Meth combo. We were actually tinkering this same idea a couple weeks ago of having a Greddy E Manage fire up a second set of injectors to supplie more fuel to get more power out of the car but I don't think we'll be testing anything out until stage 3 of the build if you guy's get a chance to do it before us let me knoe how everything go's I thought it was a very smart idea without having to go to a piggyback type setup.

 

This is pure concept as I don't understand the wiring or Electrical Engineering stuff.... I can run it past the EE's at work on Monday.


But couldn't you simply run a second set of injectors in parallel using the original injectors/ECU as a trigger. Kinda like using the first set of injectors as the switch side of a relay that keys the power heading to the second set.

 

Run each on a seperate MAF for conventional setups too

And a second knock sensor

 

I'm gonna go with the simple stuff first.

1) How do you get around the fact that you dont have the OEM plugs?

(came up with a solution for my own question)
get a standalone harness adapter like from a hydra or something and just tap in to that.

2) Would having one sensor sending single to two ECU's lower it's signal voltage and ruin it's operation?

You could maybe setup some sort of device that reads the signal and doubles it but divides it by two and sends it separately to each ecu IF there is any signal loss and this becomes necessary. (I'm no EE)

I'm gonna go over some files I had for my Subaru swap I did and see what else could trigger problems with the ECU.


Jid's solution seems easier and I don't see where it could have a fault in the tuning end of things.... sounds easier to tune then two ecu's too!

 

should't need to wory about it to much, people do it all the time with SAFC's and emamage.

 

Usually the ECU's read a signal on an analogue line with an ADC that sits behind a high impedance input. The whole point is to read the input with minimal affect to the measurement. Splicing a sensor line to multiple ECU input's really shouldn't have any affect on the sensor outputs. but don't take my word for it...

 

any reasons not to run dual injectors off of a relay system?

like can relays go bad?

Wouldn't you just scale the injectors at twice what they normally are scaled to and then tweak the latencies?

actually screw relays.
what if you split each injector signal into two and made something like this
http://www.aempower.com/ViewCategory.aspx?CategoryID=83
think it's getting 8 injectors input and output 8 injectors from it too.

(I know, I'm in a bit over my head but brainstorming is something I like to do when I'm bored and I can learn by being proven wrong)

 

I think the route they are going is when running E85 having a second ECU to run secondary injectors... Skunk2 or Boomslang harness for sure to tap the signals... I can't shoot it down to the best of my ability... Even the tapping of the sensors... they are usually an analog 0-5vdc trigger for most so I don't see that being any hinderence, and probably any mitsu ecu that ecuflash can change should do the trick that way you could scale the injectors and everything...

 

The idea is not just for twin injectors that act like double size injectors, but only 4. The idea is to be able to stage the second large set for high flow.

 

It has been done before on a Subaru I was involved with. It worked well - he used a pair of PowerFCs.

 

Aaron, I can see two viable choices.

If you run low impedance injectors like the Lucus style you can buy/build an injector driver box that takes the signal off of each of the cylinders, re amplifies it, and applies it to the second injector.

The second option which has already been done on a stock honda ECU is to simply parallel the injector off the same ecu output. I think a low impedance injector would burn out the ecu output. However Tony1 was using dual saturated Bosch 1000's on said honda ecu and it worked great. He said idle was also good. That would give you 2000cc/min of fuel to each cylinder at stock fuel pressure. If you could run around 70-75psi base you'd have 2500cc/min to each cylinder, or 10,000cc/min for the whole engine.

For me, personally, I think 2 ecu's is too complicated. Although theoretically you could flash each one differently for different levels of fueling.

 

I know it's thinking out of the box and all to do what you are suggesting. But it seems like if you are at the power point of needing secondary injectors, wouldn't it be beneficial to go over to a standalone?

You can pick up an AEM with sensors for like $1000. That's likely a drop in the bucket on the amount spent to get the car to the point where it needs more then some 1600cc injectors.

Or like dan l mentioned, just parallel off the injectors, maybe even toss in an independent injector driver to make sure the drivers can handle it. If you do that, you can likely go over to a true peak-hold system too.

 

Why not use a single high power injector and something simular to the current Meth injection methods. Then assemble us pretty simple, pending you can drive the injector correctly.

 

If you want to run the second ecu just to run another set of 4 injectors, i think is to much fuzz for nothing.

Usually nobody just have a second ecu what stands around in his garaje. So you have to pay a price on that ecu. After you have the ecu, you need another wiring harness for the ecu, the obd port... After that, you have to start cutting wires in the original wiring harness. You will get a lot of errors on the second ecu because he will not see a lot of sensors. So you will have to take some resistors to put in place of the sensors or fouling stuffs. If you have an error on the primary ecu, the second will go like it was programmed. The maf it will be a problem, more than sure you will need to run 2 mafs (let's say to also have a second maf lieing around in your garage, next to the second ecu)
After you work 4 days to cut, splice and solder wires, you will only have a car on a kind.

Financiary and time speaking, is more simple to just buy a piggy-back with comes with the plugs for your car....you don't have to cut so much...

I thinked about this some time ago, firstly i was very interested about this, but thinking i realised that you don't win anything....it is way simpler to just put a piggy-back.

Or if you want, go the whole mile and put a plug-n'play stand alone and you can do everything you want.

After i distroyed an forged engine with the stock ecu (melted only one cylinder of 4 - all the injectors were working fine) i realise that having a stand-alone is the way to go. You know everything that the ecu is doing, we does only what you want...everything is better. So for simplicity, go Hydra, for playing go Motec.


Sabin