hires vs standard msextra - Miata Turbo Forum - Boost cars, acquire cats.

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Old 01-04-2009, 10:24 PM   #1
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Default hires vs standard msextra

Is there any point in using the hires code if the car is normally aspirated, and has OEM-sized injectors?

I hear people saying it helps with better idle, etc, but as I understand it that's only if you're using injectors so large that the minimum pulsewidth is too large for low load events.

Just want to make sure that there's nothing else I'm missing!

Justin
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Old 01-04-2009, 10:30 PM   #2
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It can't hurt..
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Old 01-04-2009, 10:31 PM   #3
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I was kind of wondering this, too
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Old 01-04-2009, 10:33 PM   #4
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Originally Posted by kotomile View Post
It can't hurt..
Well... I'm running a customized 029y4, so I would have to port the code over to HR. Probably not a big deal, but I'd rather not take the time if there is no point.
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Old 01-04-2009, 10:47 PM   #5
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It's free, and you get more resolution. You might not want it now, but what about down the road? No better time than now.
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Old 01-04-2009, 10:51 PM   #6
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Ehh, that doesn't really answer my question. Telling me it has more resolution is the same as telling me that it is the hires firmware. I'm asking what it will do for me. And there's no point in switching to it if the answer is "nothing".

But if I' get a better idle, or if there are relevant bug fixes, etc I'm all over it.
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Old 01-04-2009, 11:11 PM   #7
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it adds another decimal place to the pulse width measurements so you get a more accurate tune and more control over fuel delivery. This is why people (especially with larger injectors) get a better idle and can lean out the idle more. Small differences in pulse width have a larger effect on the amount fuel delivered with larger injectors.
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Old 01-04-2009, 11:14 PM   #8
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i dont know but when i upgraded to hi res the car deff felt alot smoother threw the power band and drove alot nicer....... with the same msq
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Old 01-04-2009, 11:18 PM   #9
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I understand that it adds more resolution, and that it helps if you have bigger injectors. What I'm not sure of is that it will have any effect on a car with small injectors.

Do you have bigger injectors, what miata??
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Old 01-04-2009, 11:21 PM   #10
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Quote:
Originally Posted by johndoe View Post
it adds another two decimal places to the pulse width measurements so you get a more accurate tune and more control over fuel delivery.
fixed
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Old 01-04-2009, 11:24 PM   #11
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yup sorry. Been using it so long I forgot already what standard code was.
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Old 01-05-2009, 12:33 AM   #12
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yea i got big injectors..... im boosted.... and you should be too

but the car deff felt better when driving or wot... besides the idle being better...

is the lattest one high res 10g or is there newer?
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Old 01-05-2009, 01:08 AM   #13
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I recommend the hires, it made a dramatic difference in the idle for my stockish motor. It seems to smooth it out. Switch to it you'll be happy you did
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Old 01-05-2009, 02:08 AM   #14
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Another way to look at it is that your pulse width will be greatly more acurate, so your fuel efficiency will potentially be better because the injected fuel will be able to be closer to what is actually required.
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Old 01-05-2009, 03:18 AM   #15
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I ported the code over and quickly tested it, and it may idle better. Everything does seem smoother. But my tune is rough, so it's hard to say.

I'm not using a MAP sensor (just the AFM), so some things are sort of whacky right now, especially the idle.
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Old 01-05-2009, 01:18 PM   #16
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Quote:
Originally Posted by JustinHoMi View Post
I'm not using a MAP sensor (just the AFM), so some things are sort of whacky right now, especially the idle.
I'd expect it to be wacky as hell without the MAP sensor. You probably meant IAT?
My '94 is still N/A (stock injectors). I only ran for about a week on 29y after installing the MS before I switched to 10g. Better idle for sure, and seems to run just a tad smoother overall. I had to retune the VE table quite a bit though, which I wasn't really expecting. If you ever plan to run bigger injectors, you might as well run hires from the beginning. That way your VEs should (hopefully) already be pretty darn close when you eventually do swap injectors.
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Old 01-05-2009, 02:07 PM   #17
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When I was still NA and totally stock and went from the Low Res to Hi Res code the difference was very noticeable. Smoother idle, better fuel economy, and better engine response were just some of the immediate benefits.
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Old 01-05-2009, 03:23 PM   #18
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Quote:
Originally Posted by ScottFW View Post
I'd expect it to be wacky as hell without the MAP sensor. You probably meant IAT?
My '94 is still N/A (stock injectors). I only ran for about a week on 29y after installing the MS before I switched to 10g. Better idle for sure, and seems to run just a tad smoother overall. I had to retune the VE table quite a bit though, which I wasn't really expecting. If you ever plan to run bigger injectors, you might as well run hires from the beginning. That way your VEs should (hopefully) already be pretty darn close when you eventually do swap injectors.
No, I meant AFM. This is an STS (formerly known as STS2) racecar. I have to run all original sensors, and I can't add a vacuum line. I have a custom version of 029y4 that does acceleration enrichment based on the movement of the AFM flapper... MAFdot AE.

So, that rules out a turbo, bigger injectors, etc. Car is staying like it is!
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Old 01-05-2009, 03:44 PM   #19
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I guess I look at it this way- for a person who is not running low-impedance injectors, there is no disadvantage to using HR code, and the benefit is more stock-like precision in fuel control, which is principally of benefit at idle and low-load, which are principally the operating conditions which influence our perception of the "driveability" of a system.

For those who are using low-impedance injectors, you are likely running injectors which are quite large. Thus, you would benefit more than most from running HR. To address the issue of injector PWM drive, use JBPerf's Peak & Hold Driver board instead of the MS's internal PWM circuit. An incidental benefit is that you'll be generating less electrical noise on the MS board, and reducing the load on the ground pins.
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Old 01-05-2009, 03:49 PM   #20
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Cool, well it's good to hear from a few folks with cars similar to mine who have benefited. I sort of overlooked the fact that the PW is more precise. I was really only considering the fact that it allowed for a smaller PW.

The reason I was curious in the first place is b/c the manual suggests that it is only beneficial if you have huge injectors, but if that's not the case, then everybody should be using it!!

It makes me wonder why DIYAutotune doesn't include it with the MSPnP. I suppose the answer to that is that some people will have low-impedance injectors.
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