HellFire Status & release date annouced

[ZCurves]

Andrew,

Yes! You can use either one or neither of them. You can run Stock AFM, aftermarket MAF, or use the built in MAP sensor on the HellFire.

Len

Well, I prefer not to complicate things. Since my Z is largely stock, I am thinking that I would omit the original equip and go with the built in MAP on the HellFire.

Perhaps you could acquire a "Best Practices" implementation guide for the HellFire. For Instance, omitting AFM, perhaps Cold-Start, etc...

[superlen]

Andrew.

I do plan on having something similar to "Stages" & a nice writeup on the pros/cons of each. I posted a quick overview of this on the Zfuel thread.

For me, personally. I can't wait to ditch that cold start valve/AAR and all the associated plumbing. The AFM would be right behind it & like you run with MAP.

Lenny

[ZCurves]

Yeess sir. Lean and Mean! BTW I will send you a list of my ECU numbers soon.

[superlen]

Well...lets hope stoichiometric & lean.

10-4 on the numbers.

Len

[shawn_16]

I'm excited to hear about this! I can sell this megasquirt 3 that's on my nightstand! Sign me up!

[mjr45]

How about ZZoomTune for your Helltune. I know almost sounds Mazda-ish.

[rossiz]

Fantastic! Looking forward to getting my '78 running well.

One question: (and yes, it may be a dumb one from an old carbie guy) Will this solve the hot-start problems that plague many of us??

[superlen]

Rossiz,

We discussed this some on the original Zfuel thread (I think, it may have been on another thread but we were collectively brainstorming on hotstart), but the answer is Yes I'm pretty sure it can. It's untested of course, but that is a problem that plagues me as well so it's near the top of having a proper solution for.

The simple solution is to richen the mixture after a hot-soak condition to combat the vaporized fuel in the injector/lines from sitting. It does sound simple, but it's trickier than it seems. The question is how much do you richen, for how long, & under what conditions do you do this? I will have a configurable table in the user interface that will allow one to adjust all these parameters. Of course, I'll figure out what the numbers should be with some experimentation and have it already setup so in a perfect world you wouldn't need to bother with understanding these numbers or adjust them . However, if a customer has a car that behave a little bit different they can tweak these numbers some to dial it in. Where you live, header choice, fuel choice, driving style, ect all change the way a particular car hot soaks so it may well be a pesky thing to get right. At the very least, we should be able to make it better if not perfect.

Len

[Zed Head]

Something to think about on the hot start issue - it might not be that all of the injectors run lean, it might just be a one or two. I have the potentimoeter on my coolant temp. circuit installed for this specific reason and I can not get the engine to run smoothly by adding more fuel. If the coolant sensor was just overheated, the pot. should work. It seems more like a few injectors just refuse to behave.

Not to destroy anyone's dreams. I've found some more modern style injectors that might offer a clue. I'm building a fuel rail so that I can install them and do some experiments. But many smart people have tried to solve this problem and none have solved it simply. Most solutions revolve around removing heat from the engine bay, or running a colder engine.

Running at a higher fuel pressure would be worth a look,which you can do with the HF. It could be one reason the automakers went to 45 psi or higher. Views tend to be that they did it for emissions, but you can get a super fine mist of fuel with 36 psi, so that doesn't fully fit.

[siteunseen]

But many smart people have tried to solve this problem and none have solved it simply.

I'm not too smart BUT an aluminium fuel rail with the FPR on the back end is pretty simple.

[Zed Head]

I only added the "smart" part to give some sense of how it's not as simple as it seems. I hope you come up with something. One way to add fuel everywhere would be the cold start injector. Then it would be a hot start injector instead. Dual function.

[superlen]

I agree on just a few injectors might be the culprit. I have individual control over all 6 so I can richen up individuals.....if we just know which ones to do that with. I agree that's not a trivial thing to figure out and changing physics out in the engine bay with a better fuel rail is a much better total solution. I'm a fan of the FPR on the end & a priming pulse on the fuel pump to flush new cooler fuel on key "on". Also the higher FP will definitely help.

People have tried a long prime pulse and it didn't help. (Zed, was that you? - I know you and I have discussed this some) I think that the FPR in the middle of the rail is bypassing more fuel down one of the lines & not the other so you may still have 3 out 6 cylinders running lean. I haven't tested this at all, it's just an idea.

For the bone stock users, I'm hoping that we can quantify which cylinders need additional fuel & how much they need after a certain soak. Crossing fingers that these numbers will be somewhat universal with a stock setup. I have the following variables which I can use to base tables off of.

- Last air temp at shutdown.

- Last CLT temp at shutdown.

- Last runtime (sec from start to key off)

- Last every other variable of course, but I don't know what use they could be.

- Current air temp at startup

- Current CLT at startup

What I don't have which would be super nice, but I didn't think of until after I did my board layout was a battery backup for a real time clock. This would give me "Soak Time". which as you can imagine would be really damn handy. Right now, I don't have that. I do have a nifty idea about how to come up with it (or at least a rough idea of it using a big RC time constant on a spare ADC channel). I'll add the real time clock on the next layout for the Hybrid version.

Possibly with just the last and current temps, I can come up with something that will help. Soak time would make it easier/better though.

Len