Set me straight on MSPNP (and Hydra)
 

I have been saving up for a Hydra + Aquamist and finally have the cash to buy, but with the release of the MM9697 I have some due diligence to take care of before I can spend my money in good conscience.

My impression is that the Hydra is a lot like a Mac Book Pro; Expensive, over hyped, overpriced piece of hardware that offers seamless integration of (approved) peripherals, coupled with excellent user experience and top notch support.

The MSPNP is more akin to a Linux PC; Open source, affordable, highly flexible EMU with great community support, but a few quirks/limitations.

I would want to equip the MSPNP with the following peripherals:
750cc low impedance injectors
EBC
KnockSense
Water/Meth Injection (WI) [Devils Own?]
Wideband O2

I am 99.999% sure the Hydra will do everything I want with no hassles, and while the MSPNP is no slouch, I have some concerns.

Fact or fiction: I have read the MSI cpu just doesn't have the cycles to run a lot of peripherals and that it doesn't play well with low impedance injectors.

How well does it idle big injectors?

Can I turn WI on and off at will without needing a laptop to switch maps?

What safeguards do I have if my WI system fails? (pump failure/weakness, hose cut, injector clog, etc.)

Is the MSPNP compatible with the MSII daughter board and do MSII features mitigate any of these issues?

Anything else I should be asking about either system?


Your input is greatly appreciated. Thanks!

from what i heard, people say its perfered that you use high imp injectors, rather than low imps. dunno why though

preferred for the MS or in general? because "in general", you can run lower on-times with low impedance (aka peak and hold) injectors. that means you have a better shot at idling something as big as he wants to run.

...

as far as the hydra vs. megasquirt, i wouldn't try to make the hydra match a mac too closely. you may get deeper into the analogy than reality.

Here's some facts about the hydra:
1. it is plug and play and has FM's support
2. it does not have a LOT of information for the tinkerer out there. you either do what it's set up to do or ask FM to help you.
3. the hydra interface is satisfactory but not great. it has some quirks that you can live with but aren't as easy as some other systems
4. you dont have to use all approved peripherals with the hydra.
* I am planning to do water injection with a non-hydramist system. there's no reason you can't use the DO kit.
* I am running a non-stock injection system (coil on plug)
* some day I'll develop a wideband AFR readout for it but not today.
5. for the money, it really does a lot.
6. you can use megalogview for the datalogs!

That said, if I had anything but a VVT car, I'd probalby run another system like the AEM or megasquirt. but mostly because I like flexibility. or the possibility of it.

you should be able to turn WI on and off without switching maps. at least on the hydra I believe that's built into the hydramist system, but you could also hook an input up that either registered the "fault" from the water injection or a switch input. Then you can have it set an alternate spark and fuel map if you like. You can also use that "fault" circuit to bypass an electronic boost control with a solenoid valve so you can run wastegate pressure in the event of a water inj failure or someone else using your car. :)

I'll let the MS junkies answer the questions about that unit.

Matt

Thanks for the info Matt. I've been reading your posts and you always seem a little disappointed with the Hydra. Is there anything in particular that it doesn't do well?

I do not like to tinker for tinkering's sake. I want to dial it in and drive.

At ~$700 you can't really go wrong with the MSPNP. Have DIY burn the high res code to it to help you idle those huge injectors. also have them do the additional grounding so you can use Low Z injectors for better idling. If it doesn't do everything you need sell it for a hundred dollar loss and go with the Hydra. Your best bet is to email Jerry or Matt with your concerns and get their input.

you can't use the high res code with low impedance injectors, the high res code disable the low imp functionality to gain the better resolution, it's one or t'other....

.....unless you use Jeans Peak and hold injector driver boards....

shit.

The MSPNP for '96-'97 has hi res code which does not let it run low impedance injectors, but all is not lost. You can install a resistor pack, like the ones used on a Honda Civic, if running low impedance injectors and they'll behave like high impedance ones.

While the MSPNP does not control water injection, I believe the Devil's Own kit operates on its own with no ECU input.

Fiction - we've got all the ECU driven peripherals you mentioned running on our red car except knock sensing, and the knock sensing isn't much of a processor drain.

A bit more fact there - the real problem is that low impedance injectors can create a lot of noise in a wiring harness not designed to handle the extra current. We don't recommend running low impedance injectors on a MSPNP without adding a resistor pack, but this isn't a limitation of the main board itself, just that getting these to work well with the stock harness is tricky.

While we didn't put anything on the MSPNP that would break compatibility with the MS2/Extra code, right now the only MS2 code that would work on a Miata is the MS2/Extra Beta 2.0. Given its experimental nature, trying to turn an MSPNP into an MS2PNP is not something we can support, although I will say it's a theoretical possibility. I don't recommend trying it unless you're really familiar with the MS and would have the skills to build and install a non-PNP Megasquirt 2 on your own.

I guess the more I use it, the less I care about what disappointed me early on. Or rather it seems that it isn't an issue.

The hydra just has different (clunky) ways of dealing with inputs and outputs that make it a bit more of a challenge to get what you want. It also has much less flexibility in datalogging--which I believe seriously cripples it for the home tuner.

For one, you can't log your system voltage, yet you are supposed to be able to tune your own alternator control circuit. There are lots of things you can't log but lots of things it logs that you may not care about... like what cell you're in. If you know map and rpm, why do you need redundant info?

For two, the datalogs are very coarse. The fuel PW resolution is only like .3ms. that's like 50% of the pulsewidth in some idle cells!

Also in my version, the ancillary maps have axis labels that aren't intuitive. they dont represent real numbers that you expect to see--for instance, if you have a VVT map that's MAP and RPM based, you dont see MAP and RPM numbers on the X and Y. You see % of the total MAP or RPM spread. Pain in my ass because I have to look it up. And it changes when you change the map or rpm scale.

But do those things affect most people on a daily basis? not really.

Thanks Matt Cramer, good info on all points. However, I am a little skeptical about the statement above. On its own it has merit, more current translates to more EMI in the harness, but how are other PNP systems coping with this?

Lots of people are running the Obiwan Link and Hydra Nemesis with low impedance injectors and appear to do so with out issue. (y8s?) Is this a grounding issue as suggested by paul?

To be honest-- I'm not sure how other PNP manufacturers went about designing their systems as we didn't bother to try and reverse engineer anyone else's system, we took the Megasquirt product, added some features, updated it with the latest hi-resolution firmware for excellent control of large injectors, and packaged it up nicely for the Miata in a polished and completely plug-n-play fashion. I've had people offer to send me other companies ECUs to reverse engineer, I'm just not that interested... so as for how they do it, not sure. What we would need though, is first and foremost to use the standard MS1E code which would negate the benefits of the hi-res code and the ability to idle the big low-z injectors you're wanting to install anways, and secondly we'd need to add additional grounds to the wiring harness to handle the extra current that low-z injectors sink. Low resistance means they're going to sink alot more current, all of that has to go through the ECU back to engine ground. We're using the 3 grounds that are available as it is, and to do low-z injectors we'd want to see additional grounding over what the factory harness has to offer.

But that said-- if you need the flow only a low-z injector can provide, add a resistor pack and you're good to go... You're one of the few that need that much flow in a Miata.... if you're running those injectors anywhere near max recommend DC that's going to be one fun car ;).

yeah I run low impedance.

if it's a case of EMI issues, it's pretty straightforward to shield a custom made harness. but that said, there must be more to it or it would have been solved.