The Project Pad

MS3 can do this, how about VEMS?
http://www.msextra.com/doc/ms3/tables.html
I can't get octane on demand out of my head, and am seriously thinking about installing a second completely separate fuel system for E85 for high boost only, but need an ECU that can switch between tables and injectors seamlessly. Or a second IIC, lol

vems can table switch "live", it also supports staged injection, and pretty powerful e85 flex fuel compensation via 'anytrim'. it allows you to scale fuel, timing, and boost via analog input.

Thanks Marc, It's the "live" feature that I am concerned about. The IIc claims this as well, but I can feel a slight hesitation when I do it under load so something is getting skipped. Have you ever done this on a motor under load? Say 20 psi?

audifreakjim wrote:Thanks Marc, It's the "live" feature that I am concerned about. The IIc claims this as well, but I can feel a slight hesitation when I do it under load so something is getting skipped. Have you ever done this on a motor under load? Say 20 psi?

hm, no I guess I haven't. I can test that for you though.

why do you need a fully separate map? is there a different feature that might be able to accomplish your goals? if you're looking to do octane on demand that can be accomplished with staged injection.

I *think* I want the ability to kill the pump gas injectors completely on boost, not just add to them which is how I typically view staged injection. I would like to be able to run my current tune, and also the ability to go balls out, WG clamped closed on E85

Some bench racing going on here, but it crosses my mind every time I try and tune this damn pump gas.

audifreakjim wrote:I *think* I want the ability to kill the pump gas injectors completely on boost, not just add to them which is how I typically view staged injection. I would like to be able to run my current tune, and also the ability to go balls out, WG clamped closed on E85

Some bench racing going on here, but it crosses my mind every time I try and tune this damn pump gas.

Instead of adding onto it, couldn't you just run it in it's current configuration and kill pump gas by dropping your DC's to zero or something close to it at a certain KPA in the pump/primary injector map? I'm probably missing an obvious reason this wouldn't work.

That is indeed the idea, but then what would control the larger E85 injectors? An auxilary type map via RPM and boost is not acceptable unless it is trimmed based on all of the other ECU inputs. I am not familiar with VEMS, which is why I am asking. MS3 has separate main fuel tables that can be tied back to banks of injectors which seems like it is the best way to do it. Or one could run another standalone fuel only controller like a 1c for the second bank, but that is silly when it could all be done in software.

Marc's idea of switching maps could work if there are no events missed in the process. Missing a single injection event would not be horrible. Missing an ignition event would not be great since you are potentially dumping a boatload of fuel into a catalytic converter. What would scare me is a partial injection event or the ECU requiring a full cycle of the motor to start working again.

Doesn't staged injection give you separate channels to control different banks?

Reading some VEMS docs, and it looks like the SWITCH function could be the ticket. It's part of the staged injection, but a different operating model. Marc, is this sounds slightly different than what you were talking about. I was equating our previous conversations to the map select feature on the IIc.

http://www.vems.hu/wiki/index.php?page= ... torStaging
There are primarily two ways and reasons to stage injectors.

One reason is that you might want to switch to another fuel at a certain time, or that you just want to switch to an injector in a secondary location as it provides better atomization or some other advantage. The switch case is best controlled with load and rpm. We call this way to control the injectors SWITCH.

The most common is that two smaller sets of injectors is used to get a larger dynamic range and that only one set is used up to a certain point. We call this way to control the injectors STAGE. The stage case is best controlled with the primary sets injector duty cycle as an input. For example turn the secondary set on if the primary set is used at >90% duty and turn the secondary set off if the primary set can fuel the engine with <80% duty.

STAGE operation mode.

The STAGE operation mode has two sub modes, one where the primaries and the secondary set is injecting at the same duty cycle and one where you have a bias toward the primary set.

In the bias operation mode the primaries will just be held at a set maximum duty and the secondary set will complement them by injecting a small amount of fuel. This mode has to be used when for example a single secondary injector is used to help fuel the engine. It can also be useful when different fuels are used in the two injector sets.
In the balanced mode the two injector sets are driven at the same duty, this is useful when two sets of similar injectors in similar locations are used.

SWITCH operation mode.

The SWITCH operation mode can be combined with the STAGE-BIAS and the STAGE-BALANCED modes. The combination of the SWITCH and STAGE-BIAS modes are more likely to be useful. This can happen when a set of small primaries is used near the valve and a large set of secondary injectors is used near the mouth of the intake runner. In a case like this you might want to switch to the secondary set at a certain load and rpm, if for example the switch from the small set to the large set is not set to occur soon enough the ECU may need to fill in with some fuel from the secondary set. Or it could be that after the ECU has switched to the secondary set it finds that it will still not be able to provide enough fuel with that set alone, in that case it can start to fill in with some fuel from the primary set.

Jim, is your idea to have two separate fuel systems for 92/93 and E85? (ie. tanks and pumps?) Or do you want plan on using a flex-fuel sensor?

alxdgr8 wrote:Jim, is your idea to have two separate fuel systems for 92/93 and E85? (ie. tanks and pumps?) Or do you want plan on using a flex-fuel sensor?

This would have to be parallel systems. I'd guess Jimmy is thinking of storing 50Gal of E100 somewhere

Oh and:

audifreakjim wrote:...seriously thinking about installing a second completely separate fuel system for E85 for high boost only

Yep, separate with an 8 gallon fuel cell in the trunk. My thought is E85 on the 25-40 psi of boost range:)

audifreakjim wrote:Yep, separate with an 8 gallon fuel cell in the trunk. My thought is E85 on the 25-40 psi of boost range:)

Ah, gotcha

It would be pretty easy to build a circuit that would work in conjunction with the SWITCH setup, triggered by the second injector bank, to isolate and 'clamp' the primaries shut with a straight 12v. If you had a suitable output in the ECU you could make it a tunable, or just use the PW signal from the second bank so whenever they're on the primaries are clamped shut.

I like where this thread is going