Mini 3 Port Injection

mrbell · Post by **mrbell** » Sat Aug 27, 2005 3:53 pm

I've determined that the problem facing us now, is that we wont' know which bank to fire.
Say we have injectors a and b in the software, and ports 1 and 2 on the motor. Currently, there is no way to match these two up because the software doesn't appear to support tracking cam angle for fuel injection. So making it fire a-a-b-b would be trivial to get 2 squirts to each port, but w/o a cam sensor a-a could quite easily be firing into the wrong port, and we'd never be able to sync them up.
If I were willing to re-write all the injection code, or at least go over it all, I could make it work. But there's alot in there that I've seen that relys on crank angle. Converting every instance to cam angle, and making sure the math is correct sounds a bit daunting.
Perhaps I'll wait for the UMS... seems a bit silly to wait for hardware to handle up to 16 sequential injectors, just to get 2...

slow_hemi6 · Post by **slow_hemi6** » Sat Aug 27, 2005 4:17 pm

UMS may never happen it might just end up being an expansion of the MS2 that is allready here for coders to start hacking on.

James the extra code guru may allready have some idea or progress into this with regards to doing sequential ignition for a 4cyl with the second trigger.It never hurts to ask though,perhaps in the embedded code section.

eliotmansfield · Post by **eliotmansfield** » Thu Sep 01, 2005 11:31 am

The extre code knows where No.1 is for spark via the wheel decoding add-ons,
so perhapps the mini problem is solvable also.

Posted by email.

mikesb · Post by **mikesb** » Thu Sep 01, 2005 7:34 pm

There's a little bit more to it than two sequential injections lined up to coincide with the opening of the first of the siamesed valves. The first injection must complete before the second valve opens, and the second injection must not start till the first valve has (nearly) closed. Otherwise you'll have unequal fueling between the cylinders. See figure 4 in the attached patent someone pointed us to a while ago, it's shown very well.

Definitely possible, just a bit tricky. Don't get sued for patent infringement

.

I hate figure 1, might just as well do TBI with that manifold.

cng1 · Post by **cng1** » Fri Sep 02, 2005 1:24 am

"mikesb" wrote:
> I hate figure 1, might just as well do TBI with that manifold.

I'm looking at ways to even up the mixture on my A-series install, the current
plan is to use some ZX6R throttle bodies and add an extra set of
injectors upstream of the TBs. I'd plan to use similarly sized injectors,
using just the upstream ones on light throttle openings to give me an
SU-style wet manifold. At WOT the butterfly doesn't aid the mixing of
fuel and air so you may as well use the injectors close to the port in as
well.

Of course it's far from ideal but it's got to be better than the alternative.

Posted by email.

edis · Post by **edis** » Sat Sep 03, 2005 11:18 am

Whats the problem with the standard mini injection?
Is it a poor solution to the problem?
or can it work well with megasquirt?

(sorry newbie to EFI)

I have a Carbed mini and just got MegaSquirt for the ignition, and am thinking about Fuel.

Ed

nobbi1977 · Post by **nobbi1977** » Sun Sep 04, 2005 12:41 am

edis wrote:Whats the problem with the standard mini injection?

I think this point has been covered well in this post and done to death in many others. A quick search will provide a mine of information

Andi

tobyanscombe · Post by **tobyanscombe** » Sun Sep 04, 2005 12:58 am

Kinda on topic but I have MSn'EDIS installed on a MG Midget in spark only mode at the moment.

Spent a couple of hours at a really good road in Croydon (one that activly seeks your involvment!) to set up the base spark (no vacuum yet as I wanted to get the 100kpa line sorted first) and managed to sort out a very smooth curve for power and torque. Power is up compared to the old dizzy (same needle in SU) and torque is most certainly up!

Final runs produced 84 Hp at the wheels with an estimated 105 at the flywheel (based on measured drag) with torque up to over 100Lb/ft from 3k to 6k, peaking at 105 Lb/ft.

All this from a 1310 with a 270 cam and a single SU! (not intending to start a numbers debate here) but start with the ignition side whilest thought goes into the fuelling side....

Now that 7 port heads are back and avalible (although not cheap!) it does offer a potential route.

cng1 · Post by **cng1** » Sun Sep 11, 2005 6:05 am

"tobyanscombe" wrote:
> Final runs produced 84 Hp at the wheels with an estimated 105 at the flywheel (based on measured drag) with torque up to over 100Lb/ft from 3k to 6k, peaking at 105 Lb/ft.

Any chance of posting your ignition vex? it would be interesting to
compare and contrast with my own guesstimated one.

Posted by email.

tobyanscombe · Post by **tobyanscombe** » Sun Sep 11, 2005 7:38 am

Chris - I'll do it tonight (on a different laptop). Looks like I could be borrowing a Weber 45 + mani next weekend so that will make an interesting comparison! Will have a LM1 by the next RR session so should get a better metering option (Cyls 2/3 and 1 have bossess welded with the idea of a dual input at some point).

How goes your project?