flounder

Hey ya'll, the mighty flounder here with a question for the emanage faithful.

I'm running an emb on my 99 with all the goods connected. The begi s kit is on the way and i'm crossing the t's etc..

My question(s)-Im running stock pump and injectors and with an intercooler i'm shooting for 8psi to start and hopefully 10psi eventually. On the 99's is all that's required to run those numbers the emanage blue with the injector, ignition and boost harnesses along with the support tool software? Or will I still need a new regulator and/or a higher flow pump? I have an lc1 WB too that will be installed once the downpipe gets here.

Thanks and have a nice day!

Flounder.

elderc

You can run those numbers on the stock fuel pump. What size injectors are you using ? and what whp are you looking for ?

miataspeed2005

iTrader: (3)

^^^He said stock injectors, I'm pretty sure you can run 8psi on stock inj as long as you have a fpr

dustinb

What turbo did you order with the S kit? I personally think your injectors are going to be having a hard time keeping up with 8psi.

flounder

Hey, thanks for all the replies! I'm using the chinacharger equivalent of the gt2554.

My original question was if the emb replaces the need for an adjustable fpr since you can extend the pulse width of the injectors to add fuel, or is an fpr or higher flow pump still needed at my power goals?

I would like to see around 170-180hp at the wheels, anymore than that and I understand that I will need to upgrade at least the injectors.

Thanks again for any info.

-flounder

dustinb

No you don't need a FPR since you can increase fuel via the e-manage.

flounder

Cool man thanks!

miataspeed2005

iTrader: (3)

You do need a fpr you'll run out of injectors at stock fuel pressure.

flounder

So which is it?

Or a better question, how far can I go with the stock pressure and the emb?

y8s

iTrader: (8)

actually since you have a 99, an FPR wont do much for you because it has a returnless fuel system and the regulator is in the tank.

the pump is fine for supporting larger injectors though. stock injectors will not be able to supply the fuel for 10 psi at the stock rail pressure.

but depending on how much the EMB lets you control pulsewidth, you might be able to decrease it enough to idle a larger injector (440cc?) and increase it enough to not be scary lean at 10 psi. the wideband will you tell you right away in any case.

miataspeed2005

iTrader: (3)

didn't know that, I thought they were all the same...But yeah I don't think stock injectors will do it, and you might be using 100% of the efficiency and they could get stuck open...You would wanna be at 80%, if I was you I would go with some 440's that way in a month when you get boost addiction you have the right injectors to do it. I don't know if the EMB will handle 440's tho.

Use this web site to determin what size you need.
http://rceng.com/technical.aspx

Joe Perez

iTrader: (8)

The EMB doesn't directly control injector PW, it trims AFM. Not as versatile as the EMU in this regard, but workable.

You definitely want larger injectors. You MIGHT be able to get away with the stockers at 8 PSI, but I wouldn't want to try it on my car. The NBs, in particular, are reported to experience a droop in fuel pressure at the rail at higher loads, which makes sense, as you'd expect some pressure drop across the extremely long line between the regulator and the injectors.

How big? Common wisdom with the EMB was historically that 50% over stock was the limit insofar as being able to retain anything like a stock idle, though of course this was largely based on experience with the 1.6 cars, which used a mechanical VAF sensor. The rather limited data which I've seen on the 1.8's MAF sensor suggests that it does not have a significantly larger range than the older VAF sensor, however Bell ships 440 and 550 injectors with their Xede, which functions similarly to the EMB in this regard. Seems to work for them.

I would suggest that 360cc injectors would be an absolute minimum, though even there I'd think you're risking running out of headroom as you turn up the boost. 440 or 465cc injectors would be safe at the power levels you're likely to be running, I just can't vouch for how well the EMB will be able to idle them...

flounder

Hey Joe, I heard you shot your woman down? couldn't resist.

Anyway, I have the emb wired up with the injector and ignition harnesses so I believe I can control pulsewidth to the injectors as well as retard timing.

I read about the returnless fuel system on the nb's thats why I ended up buying the emb over trying to convert it over and use a afpr. I am sure once I get used to 8psi, i'll be upgrading the injectors (I was thinking of the black mazda 323 injectors, I think they flow 360cc) as well as everything else

As for the pump, what about a 190lph instead of a 255? Will that along with the larger injectors support up to 12-14 psi? Just wishful thinking at the moment but i figured i'd ask?

-F

Joe Perez

iTrader: (8)

The EMB can lengthen injector pulses directly, in much the same way as a voodoo box or a Powercard. It cannot directly shorten pulses. Negative fuel trim is accomplished by manipulation of the airflow signal. This is one of the major characteristics which distinguishes the EMB from the EMU.


It's doubtful that a larger pump will change anything. The stock pump on these cars is entirely adequate for >200 HP, and on the NA cars where the regulator is on the rail, no fuel system mods (other than injectors) are needed to achieve this.

On the NB, the problem is simply that as flow rate through the fuel supply line increases, so does the pressure drop across the line. On the NA, this is compensated for by the FPR. On the NB, the FPR is blind to what's going on at the rail.

Now, with large enough injectors, you'll be able to get enough fuel through regardless of what the pressure looks like. Some folks will argue that as pressure decreases, so does atomization quality. To what extent this is reflective of a decrease in power or economy is questionable. Fixing this involves either the use of an RRFPR back by the stock unit, or the addition of a fuel return rail (essentially, reversion to the NA's fuel setup.)

flounder

Great info man, thank you.

So the emb can take away fuel with the air flow maps, while with the ultimate you can simply use the same injector map to lean and richen the ratio? Is removing fuel even necessary when tuning for boost?

I suppose i'll have to wait till everything is installed to check actual a/f ratios and go from there on the larger injectors, I'm glad the pump should hold up to around 200hp though. Have you heard anything about those 323 turbo injectors or can you recommend something similar in the aftermarket? I don't think I want to go too big, I'd like to be able to sit at a stoplight without flooding it.

Joe Perez

iTrader: (8)

Removing fuel is necessary for running larger injectors. I can't remember how the EMB setup software presents this to you. On the EMU, there's simply an injector scaling constant- you tell it what size your old injectors were, what size the new ones are, and it automagically sets a permanent trim behind the scenes, so you don't have to account for this in your fuel table. Afraid I can't be of more specific help on the EMB software here.

But the basic idea is simply that you have two separate phenomena to account for, which may or may not be done in the same place in the software. One is to set a constant negative scaling to account for the increase in injector size, the other is to set a non-linear positive scaling when in boost, to add fuel beyond the VAF sensor's ability to account for increases in airflow after a certain point.



Check your injector duty cycle- that's the magic number. If you are holding decent AFR at 80% DC, you're ok. If you're holding decent AFR at 95% DC, that's bad.


Yes.


Five-O is my old favorite. Real knowledgable guy, who is experianced at custom-milling varios injectors to fit the Miata. I got my 465's from him.

Deatschwerks is a relative newcomer, however their stuff is truly plug-n-play, both mechanically and electrically. Boundary Engineering sells their stuff.


You won't flood the motor. You'll just have a lumpy idle. Not the "good" lumpy idle, like a cross-plane V8, unfortunately.

flounder

In the parameter section of the emb software there is a spot for injector change correction. You enter your stock c.c. then the size of the upgraded ones and apparently it works some sort of magic? Not sure what, still learning the software at this point.

I am able to see duty cycle currently, i've been seeing around 50% at WOT. This is pre turbo mind you.

I have the emb wired up to get used to the software before the kit goes in. I've been adding fuel slowly, so far between 2-8% up from 0 map, and i've been reading the spark plugs to get an idea of mix. I'm really looking forward to getting the wideband installed!

IDK, I'm sure i'll be back on here asking a ton more questions once everything is installed but for now, thanks for all the knowledge.

-Flounder

Deatschwerks

You shouldn't have to worry about idle issues if you can get the tune right. We have several of our 1000cc+ injectors in various applications that still have a stock-like (some even reported better!) idle.