Joe Perez

iTrader: (8)

As compared to Hi-Res on a 3.0 board? No dedicated ground plane, thinner traces, no proto area, no overcurrent protection...

Oh, you mean disadvantages to HR as compared to LR assuming both are on a 2.2 board. None. The only functional difference between HR and regular SnSExtra is the injector PW resolution and lack of Lo-z drive capability.

elesjuan

iTrader: (11)

:jerkit :


So even with a flyback board with HR you lose the ability to use low-z injectors? Good deal, I'll look into giving that a shot.

Joe Perez

iTrader: (8)

Correct. The reason for the discrepancy has to do with the limited hardware resources of the CPU. Remember that when you get right down to it, pretty much everything in the MS is time-based. Fuel, ignition, it all happens by counting the time elapsed between interrupts, and turning ports on and off for specified lengths of time.

What the HR code does is to increase the resolution of the time calculation on the injector drive. It does this by repurposing one of the CPUs high-precision hardware timers to do the fuel calculation. In the base code, this timer was used to do the PWM calculation for the injector current-limiting, and the fuel calculation was done with a lower-precision general purpose timer.


The Flyback board is nothing more than a couple of transistors which, in the 3.0 schematic, are already on the main board. The overall design of the circuit is identical between the two, only the location of the parts changes. Be it a 3.0 or a 2.2 with Flyback, the same CPU resources are used to control the injector drivers. If those resources are unavailable, the drivers cannot function in PWM mode. Also, understand that the "Flyback circuit" is purely a damper circuit that is needed to protect the main drivers when they are operated in PWM mode. An unmodified 2.2 board could be run in PWM mode with lo-z injectors, but the drivers would probably be damaged.


However, there is a board which replaces the injector drivers altogether and does the Peak & Hold current limiting in hardware, without intervention from the CPU. It will thus work with HR code. It's made by the same folks that brought us the JimStim: http://www.jbperf.com/p&h_board/index.html

They're using an LM1949 IC, which is a special purpose IC designed specifically for doing low-impedance injector control. It's a beautiful design, you just feed it the regular injector signal, and it takes care of doing the current ramp-down after the initial opening period.

I think Abe is planning to try it as he's been having electrical issues with his on-board injector drivers.

rb26dett

Actually (from the horses mouth) it's "about 0.02 - 0.03" ms (20 - 30us) fuel resolution. MS2 does it to 0.6666us in hardware and if you look at the comparison chart between different ms variants here :

http://www.msextra.com/ms2extra/MS2-...l.htm#features

It still says 100us* where * = "hires can do better than this, but we aren't specifying how much"

I just thought it was unfair on MS2 to claim ms1e hires can match it for fuel accuracy. It simply can't. Light years ahead of ms1 ah la plain though, so your excitement is justified :-)

It's worth noting that the software accuracy behind the hardware output makes a big difference too. Case in point, ms2 b&g vs. ms2e, ms2e has extensively rewritten math to make use of the hardware accuracy that ms2 b&g just doesn't have.

Fred.

Joe Perez

iTrader: (8)

Uh, Fred, I don't think anybody here was claiming that MS1-HR was equal or superior to MS2. I think we're all in agreement that MS2 is more accurate than any MS1 with regard to fuel resolution.

Exact specs are hard to come by, but some numbers seem to show up more often than others.

To quote Phil, James & Co. from the MS1E-HR manual:
and to quote the B&G documentation for MS2,So, regular MS1 or MS1Extra has a resolution of about 100µs, MS1Extra-HR has a resolution of about 35µs (three times more accurate) and MS2 has a resolution of about 1µs, blowing them all away.

I'm sure there is point of diminishing returns in this, though I don't know where it is exactly. I doubt that increasing the resolution to, say .01µs would buy you anything palpable over the MS2's stock 1µs resolution.

The point is simply that going from MS1-Extra to MS1-HR, and gaining three times the fuel resolution, is a significant change.

Toddcod

iTrader: (8)

YEaaaaaa.......
So I have MSPNP9093. i just installed it recently. I am installing my 550cc injectors. So I just need to download the Hi res and burn the firmware. Then everything works the same. Just more precise.

I was told my injectors were RC550CC from flying Miata. But how do i make sure they are rc550 and High ped. A red neck did own it.

Joe Perez

iTrader: (8)

Assuming the 550s are hi-z, then yes. You'll probably need to tweak your VE table a bit.

The latest HR code can always be found in the "Latest HiRes" thread here: http://www.msextra.com/viewtopic.php?f=90&t=25336

rb26dett

Not quite, but it would have been easy to read this :

or this :

And infer a granularity of 1us exactly the same as (not better than or worse than) ms2.

That is all I was getting at.

I was quoting an MS1Extra HiRes Author who I asked directly about the accuracy. Hence my comment "straight from the horses mouth" which is a little bit different to "straight from the horses documentation" although either of them could be as out of date/inaccurate as the other I guess :-)

Agreed, or perhaps as much as 5x increase in precision.

Additionally and somewhat off topic : ms2 res = 0.666us, not 1us :-)

When someone asks me about them I say this :

MS1base <= MS1Extra < MS1base HiRes <= MS1Extra HiRes << MS2 < MS2Extra

Which I think is a fair summary most of the time.

Fred.

Saml01

iTrader: (9)

Damnit, I really have to go do this. It takes like 5 forking minutes, and im still putting it off. I guess I just dont want to remove the MS from the car if I need the cap mod.

Are you guys just reusing your low-res msq files, or re entering tables by hand into the hi res version?

crashnscar

iTrader: (9)

Just load your low-res msq and tweak.

mikeflys1

iTrader: (2)

Reused mine...i think they only re-entered by hand because of a bug in the previous version.

rb26dett

No, it's because of namespace/meaning differences in the contents of the tune. The way various vars are used can change between two versions and cause chaos if it doesn't match up. Usually it matches up though, so if there are no warnings or few warnings, you are probably OK. In the case of warnings, check the stuff they refer to.

ini files on the other hand, NEVER try to use those! MS has direct memory addressing through serial and a wrong ini (as it says when you try) will/can ruin everything :-)

Fred.

Saml01

iTrader: (9)

Guess ill throw it on either today or tomorrow and see what happens.

I really hope I dont have to pull the MS for the cap mod, I hate taking it apart. Luckily I retained all my unused MS parts, and found a .22uf cap I could use just in case.

pace

iTrader: (1)

I have been experiencing a driveability issue whereby the car would jerk and stutter if I was coasting downhill with the throttle just cracked open a hair. My assumption was that it was due to the overrun fuel cut option which I had enabled. I had tried tweaking the fuel cut parameters with no success.

After loading the high-res code and re-tuning the VE map for it, the issue appears to be gone !

Additionally, I now have a stable idle at 13.5:1 whereas it would oscillate wildly with the 029y4 code if I tried to lean the idle above 11:1.

I am impressed with what the high-res code has done for my setup.

levnubhin

iTrader: (30)

My pulse gauge reads neither. Any ideas?


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kotomile

iTrader: (24)

you're running 029v levnub.

Joe Perez

iTrader: (8)

"1.7" instead of "1.745" was just an example, to illustrate the use of one decimal place vs. three. "2.1" is a number with one decimal place of precision. Also, as kotomile pointed out, it says right up at the top of your screenshot (on the titlebar) that you are running 029v, which is not a HiRes build.

kotomile

iTrader: (24)

I think he was being facetious FWIW.

Saml01

iTrader: (9)

I installed it the other night, and just at IDLE I noticed that it was already superior to the low res firmware. Cant wait to drive it today but I imagine it being pretty much like the thread title and then some.

levnubhin

iTrader: (30)

Anyone have any intrest in spending a few mins on the phone with me and walk me thru the install? Id appreciate it big time and would be sure to return the favor somehow. Im just affraid that I might blow something up.
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