Manolis_D

iTrader: (2)

Dude, that is waaaaaaaayyyyyyyy too lean at 5k.. You need ~12:1 all the way across, especially at 10 psi with the stock S4 turbo. What is the S-AFC setting for that rev range? I'd add in at least another 10% more fuel there (should take it to ~12:1).

Don't blow that thing...
-Manolis

T210thAnniv

Scott 89t2- the reason i didnt go leaner after 6k was because my boost dropped from 10psi to 8psi so i was in luck kinda. At 5,000 rpm the S-afc was set around 35%+ i believe, and i couldnt make it any richer then that, the s-afc just wouldnt go higher.

Kahren

iTrader: (13)

would be nice if u read the posts too...
u need 12:1 across with the stock turbo?
what is this supposed to mean does the stock turbo affect the afr somehow?
you could probably argue that with diffrent boost levels u need diffrent afr but he is ONLY and i repeat ONLY runing 10 psi...

Kahren

iTrader: (13)

and and for your information the EGT is a piece of **** unless u placed it where it has to be exactly, an inch diffrence woudl matter by a lot only cause u are seiing 800 on it doesn mean crap. u coudl be runing VERY lean with that thats when the temp will start to go back down. ask anyone who knows what they are talkign about they will tell u this.

gsracer

Easy there amigo. Obviously the best place to put the EGT probe is the exhuast manifold, but most people don't feel like taking the turbo off and tapping the probe in there. There are many, many people running with the EGT directly behind the o2 sensor, and obviously exactly how far back will make a difference. Go through the archives and you'll find a general consensus of 800 degrees being where you def. don't want to go over with the probe mounted near the stock o2 sensor. Of course every car is different as well as the variable of where exactly the probe is placed so getting a dyno with a wideband is the best idea so egt numbers can actually be correlated to a/f ratios. I think it's simply a bit of a shock that a t2 is running lean in the mid rpm's at only 10 psi bleeding down to 8 with a walbro 255. I, as well as others, have assumed 10-11 psi on the walbro with a rewire was a solid set up. I think you need to understand that at least for me this is one hell of a shock. I assure you I'll get my car on a dyno with a wideband soon and post up the numbers.

Kahren

iTrader: (13)

i am easy i just dont like when peopel blow their motors out of stupidity, yes u are right the egts can be compared with the afrs but u need to do it ina controlled environment and take close note. most peopel just get egt gauges and thing that if they dont see over 1k on it then they are all good to go... this is not true...simply gettign a freeflowing exhaust will drop your temps, there are too many variables. even the dyno is not perfect enouf, its close to a real world but its better to tune the car while it moving. anyway..

his pump IS rewired, i donno if it coudl be wired wrong or what not, it should be puttign out mor epressure at the same rpm and volts as i understand since it is a higher PRESSURE and flowing pump. BUT it doesnt seem its enouf...this means either there is somethign wrong witht the pump, the wiring of the pump, or the injectors, becasue he IS hittign max duty cycle at that rpm. the only thing saving his *** is that his boost dropps of at higher rpms so u can take control of the fuel again..

///3oris

Ok, I'm new on this board, so quick shouts to everyone.... "HI!"

I am not sure why you guys sometimes argue **** like this for so long... maybe it's miscommunication, maybe it's misconception, maybe it's the lack of knowledge or stupidity in the first place. But here's the deal with fuel pumps:

THEY DO NOT INCREASE YOUR FUEL PRESSURE!

They just pump more fuel if you use it, otherwise, an FPR (Fuel Pressure Regulator) is in place to regulate your fuel. On my car, for example (non-FC, so hopefully I'm not too off-base here), the FPR is at a constant 3.5bar. Guess what? I get that pressure at 1k rpm, 7k rpm, when I upgrade my injectors, when I downgrade my injectors... ALWAYS. The only way I will not get 3.5bar is if my fuel pump can't keep up with my fuel consumption.

So PLEASE don't be pissed at me, but before you think a fuel pump will increase your fuel pressure, think twice. This is why RX-7's have such a bad rep, and why I hear about their reliability all the time. I personally Love RX-7's, but the assumptions made by some.... "bright" .... owners gives them all a bad rap!

Also, DO NOT go more than 10psi on your stock fuel injectors no matter how high your S-AFC is set... because the injectors are maxed out (as explained earlier, if some weren't paying attention).

K, that ends my post... sorry I had to introduce myself in such a manner. Hope I saved a couple of rotaries from their short-lived lives.

Boris

Edit: I was going to clean up the language a bit so that I don't get flamed upon... but I guess it's a worthy cause, so I'll stand up for it. I'm only watching out for YOUR apex seals, guys....

Another Edit: I forgot to mention, you CAN increase the pressure if you pump past the capacity of the FPR... but a Walboro 255 wouldn't do enough, IMHO. You'd probably need two!

Kahren

iTrader: (13)

yep what he said, i am more then sure taht his fuel pressure in teh rail is the same as BEFORE the addition of the pump. clamping off the vacuum/boost hose to teh fpr will change the pressure...

///3oris

Clamp is the ultimate "DIY" (cheap ) FPR mod... THAT would increase pressure for sure...

gsracer

I was pretty certain that the walbro overran the stock fpr which is why it worked, and also resulted in the really crappy gas mileage. Many people upgrade the FPR with the walbro because the stock FPR can hardly keep up.

This brings into something I've wondered about. Why don't I see the use of RRFPR's more often in here. Usually all I here about is walbro with bigger secondaries. Wouldn't a walbro and a RRFPR be a pretty good combo as well as a safc with 720's.

///3oris

Well, if you are correct, and it does pump past the capacity of the FPR, then the pressure would increase, but not NEARLY enough to run 14psi (as I've read on another thread). If anything, it'll allow you to run 10psi more safely. We'd need emperical data... but honestly... if you haven't been on a dyno, don't push your car. That is a deathwish with rotaries... unless you guys are all like voskos and have standalones with widebands and big *** injectors and got nothing better to do (I'm kidding, Vosko! ).

One reason against RRFPRs is that a properly tuned system shouldn't need one. The ECU should control how much fuel should be dumped based on Load/RPM... it makes tuning easier knowing that hte pressure is the same throughout the rev range. That is obviously a more subjective oppinion. If you don't want to upgrade your injectors, then a RRFPR may not be a bad idea if you plan to stay with low boost (10-12psi). But for the price of a RRFPR (at least a good one, like Corky Bells), you may as well pluck down the money for the injectors and go on a dyno with your S-AFC. Much safer and better in the long run, plus gives you some room for "growth."

Boris

EDIT: Before I get picked on... there is MORE to determining how much fuel to dump besides Load/RPM... but I'm trying to "KISS"

Kahren

iTrader: (13)

once u upgrade from stock injectors to somehting bigger teh stock fuel pump cant FLOW enouf, so the pressure drops which is a bad thing... this is why peopel upgrade the fuel pump to have better FLOW, so those bigger injectors get teh pressure they need. all injectors are rated at whatever cc at CERTAIN pressure, i belive teh stock t2 are at 38 psi of 550cc. so if u get 720cc with rating of the same 38 psi the stock fuel pump will most likely NOT flow enouf and will run out of breath. FLOW and PRESSURE are diffrent things though they are related... just fo ryour note.
same size injectors WILL flow more at a higher psi then they are rated for...
by looking at the WHP from this car and the upgraded pump i am willing to bet that the walboro is not raising any more then stock psi at the fuel rail, and if it is its very minor.


liek was stated before the fpr is more of a cheap mod and a fine tunning device to havign big injectors and a fuel pump. but to each his own.
if u dont want to tuen your car the right way and spend the righ amount of money buying the right amount of parts its all up to u if u want to see your apex seals and not. there is a fine line between a blown motor and a running motor.

T210thAnniv

OK, relax, take a DEEEEEP breath people

importboi22

oh ya your injectors are certianly not maxed out the stock comptuer will not let them go over 62% duty i beleive :P safc just changes airflow and there in turn the computer compensates by opening the injectors more but.... if the stock comp wont let em open mor than 62& duty your screwd now arent you?

Kahren

iTrader: (13)

now read again what u just said
u are contradicting your self

Manolis_D

iTrader: (2)

Haltech time

I was able to run ~7 psi on a TO4B 60-1 with the stock 550's and a Haltech. See how much easier that would be? (not that I'm pro-EMS or anything )

Can you drop boost down to ~8psi until you get your bigger injectors? That might be a good idea.

-Manolis

///3oris

Import, if what you're saying is correct, then you guys should reconsider using S-AFC all together... because S-AFC only fools airflow (as you've mentioned). You can, on the other hand, tune the signals coming OUT of the computer using a Power Commander (http://www.powercommander.com). To see a writeup on how it's used in a BMW 4cyl, check out this link: http://ackthud.com/shawnfogg/fuelupgrade.htm

Since you guys have 4 injectors, this would be a perfect mod for you guys. In fact, sandor, you should consider this instead of S-AFCII when you upgrade. This is mostly done on BMW's because of OBD-II adaptation, but _IF_ import is correct in saying stock computer won't let injectors go past 62% duty, then this is a great solution for running more boost utilizing stock injectors.

Don't forget though.. if you max out the duty, you spray while the chamber maybe closed, this may not be ideal for a rotary... doesn't hurt my piston though!

Hope that helps somewhat...

Boris

Kahren

iTrader: (13)

its not about the boost, how much power were u making at 7 psi at the wheels, he is making about 220 and is maxed, evntough u will flow mor eat the same 7 psi its prolyl still not enouf to make a difffrence. i fyour 7 psi on that turbo will equal same power output on the stock turbo then that explains it.

he cant turn teh boost down since the wastegate is all the way open.

he is far away from goign EMS, and ems is not a solution to all but this is a whole new topic on its won

importboi22

not really what im saying is with all the little piggybacks that interupt AIRFLOW to the comp to mess with fueling needs will not work with our computer becuz no matter what the stock comp will limit the injectors to 62% duty... one piggyback i know of that modifies the signal to injector itself is the hks fcon there for itll alows more duty to be added

Kahren

iTrader: (13)

ok then if u are right how can the stock system be good for 220 at the wheels with 550 cc injectors at about 38 psi in the rail and with that AFR? with currrent BSFC

in other words the 550cc at 100% duty with 38 psi at the rail are capable of 220 at the wheels WITH the afr he is running.

T210thAnniv

MY FMIC should be here this tuesday coming up as well as my injecrtors, so the beast isnt going anywhere till i put those in . I think once i put the 9500ccs in it will solve the problem, because i wont have to turn up the s-afc as much, and them being 950cc it wil be plenty for 10psi throughtout the rpm range and im sure it wont be past 60% duty cycle with those sizes, but hey what do i know?? thats why i am here

///3oris

Sandor, your car is still slow... go to sleep!

JK... you'll be fine w/new injectors.

Boris

T210thAnniv

HMMM, Didnt i beat you like 3,4 weeks ago? lol, jk....well not about me beating you but you know you shoudl be the one going to sleep cause you have to WORK tomm, i am laid off so i can relax

importboi22

stock fuel system if you can run up to 85% duty should be sufficent for up to 260 at the wheels i beleive , let me check agian

importboi22

taken from rx7.com

"ECU Controlled Max Duty Cycle is the maximum injector duty your reprogrammed computer uses. For reprogrammed ECUs, please contact your ECU programmer for specs. If unsure, use 80%. The Stock ECU is approximately 58-63%"


ive always wanted to use that smiley