Tom454

No O2 ports on the side-pipes I have.

eutu1984

Tuner Pro is free, http://www.tunerpro.net/
you can get good advice on tuning here, thirdgen.org, and gearhead efi forums.
for hardware you can go to http://www.moates.net/

GREGGPENN

They way I read it at TGO, our ECMs "know" to kick into double-fire mode under certain conditions or pulse-widths. I didn't understand this "auto-switching" logic was built-in...though I haven't (yet) asked for it to be confirmed.

There was a member(s) who've run 500+rwhp on 24's. I never could figure out why...though I probably read someone mentioning double-fire mode. Or course, I quirked my head to the side...like a confused dog...and made the same "huhrumph" sound. I never figured out how to active double-fire mode, having never seeing a parameter for it in my BIN. Now, it seems it's automatic? Huh....

If this is true, the size of injector doesn't have to be nearly as big as you might think. Basically, I guess this is saying 24s can perform nearly double their size? Of course, consider the headroom you want to leave to avoid going "static".

For idle/emissions/economy, you basically want to stay on the smaller side of your choice(s) to maximize atomization.....at least that's what I've read SEVERAL times. OTOH, I've never read ANYTHING on the effect of fuel sitting in the intake tract (behind a closed valve) waiting for "batch #2" to finish filling the port.

Plus, you have scavenging events which may tend to push fuel back into the plenum?

Kind of surprising I've not seen much about this before.

aklim

Got a link to that TGO mention? Way I look at it, you'd have to increase fuel pressure to something like 75 where it begins to push back at the injector when it is trying to open. Regardless, increase pressure and running static would be the maximum an injector can do, I would think. According to the calculator by RC Engineering, you can crank it to 75 and be willing to run static and 24 will support it. If I build a 500HP motor, it won't be cheap unless I stole it. I wouldn't risk that much money to save on a set of injectors. Penny wise pound foolish if that pump doesn't keep up and you don't run WOT every.

Tom454

Yes... I will probably go that route. I emailed moates yesterday. Waiting for a response. I need to do EECIV Ford as well. Anyhow... looks like it is a "download" which I do not like. I will likely have to download it to one laptop and then transfer it to a second "utility" laptop with no internet access... so this presents a problem for me logistically. I would pay for it on hard media in a heartbeat but can't find that option anywhere.

htrdbmr

Tunerpro RT, and Craig Moates for the hardware.

aklim

For me, the choice of having it done or doing it myself all boils down to economics. A one off, I definitely don't see the economy unless it is low in time and equipment. I don't see any reason to risk screwed up gears and buying the tools and learning if I change them once every 10 years. Tuning takes time to learn and dyno time to see what happens when you do this or that for power runs. I have no problem buying a $1000 scanner if it does all my vehicles but a special module of pulse C4 ABS, no.

GREGGPENN

Post#2 in this thread...
https://www.thirdgen.org/forums/dfi-...-strategy.html

OTOH, I found CORKVETTE1 saying he ran as much as 63PSI in his low 10-sec cars. (He tried 3 different motors and the way I read it...and used the same 24's in a 355, 400, and 434ci block. Didn't find anything on pressure changes for each motor.)

Anyway, until they went to sequential firing, it sounds like you could essentially double the size of your injector to figure out it's capacity.

It's been quite awhile (e.g., 5yrs), but I seemed to recall I might need a bump in injector size OR fuel pressure if I converted to an HSR....with my 24s.

aklim

Assuming that our ECM is capable of doing this, I don't know what the drawback will be, and there is always a price for any such thing. I don't have any need to program my own ECM so I never wanted to spend any time with the program to tear it apart. Last time I had to have it changed was quite a few years ago. Wasn't worth the time for me. I just went with someone who was an expert and had him do it and decide what size injectors to use.

I don't know what the HSR needs but I did have to get a tune from Lingenfelter after the SR intake and headers on my F-body to make it run factory smooth.

GREGGPENN

They way I read it is our ECMs are ALREADY doing this. They stated it was in the "firmware"....and it was stated by a longtime forum moderator. This makes me believe Russia really DID help Trump. But, I digress LOL.

On mine...even with the super-hogged-TPI, there were tweaks in the fueling tables. I doubt that contributed to "butter-smooth" operation which likely had more to do with open-loop tables and tip-in.

Open-loop fueling is also another consideration even if the MAF tables are set correctly. Mostly, I think extra fuel is added to "protect" the converter from burning up. Factory engineers deliberately run converters richer to LIMIT temperature...insuring better longevity. If you look at TPI "power enrichment" tables, extra fuel is tapered off where the top "harmonic" performance also falls off. A Superram is much more linear -- meaning extra fuel is continued in higher rpms. Minirams probably add the most up top. IOW, fuel is added in the areas where wave harmonics are the highest....

I posted about the true purpose of power enrichment "mode" last fall. A couple of people guessed it mostly had to do with emissions. It wasn't until I read that extra fuel actually COOLS converters that it made even more sense.