Cwaters

He uh, said in the last post that they were re-doing their web-site today . That *might* be why it isn't working

Cory

Wanked_FC

iTrader: (1)

Does it actually eliminate fuel cut, or is it just like the external fcd? If I'm running 10psi will the ecu know I'm actually running 10psi, or will it still think its running 8.6?

Fitness Stain

thats what i wanna know cause if thats the case, i wont have to upgrade my fuel as soon......that would be a worth while mod for sure!

hit us back with details...you cant leave us hanging

chris1234p

By eliminating the fuel cut code the ecu will look for the stock fuel maps past 8.6psi right? This would be a huge advantage over the regular fcds as people with lightly modded TII's would have no problem controling the extra power gained and they wouldnt have to spend 300+ for a piggyback until later.

Wanked_FC

iTrader: (1)

Good stuff, I'm definately gonna get one. My car's down for winter now anyways... stupid midwest. I can't wait until the 550/720cc ecu comes out. Good work Henrik, you da man!!!

HAILERS

******. Then you need bigger injectors. Actually you should have put them in at 80%. *********8

Actually I've got a Fluke that shows duty cycle either in MS or PERCENT. I remember nailing the throttle this morning around three grand in fifth, up a long grade, and with the meter on the primary injector saw what I remember as 86oercent just the moment prior to the secondary injectors coming on line, whereupon the primary dropped to I forget what, somewhere in the thirty something percent and the percent gradually rose as I got near the top of the hill where I believe I saw something in the sixty percent range and something over 110mph.

Just saying your remark about 80percent fits in with what I saw this morning.

j9fd3s

iTrader: (3)

yah they actually changed that for the fd (maybe the cosmo too) to the secondaries coming on at 1psi, or i think its like 5500rpms

mike

Icemark

Again that wouldn't work, because the S4 TPS is at 100% on at 1/3 throttle

Henrik

Hi guys,

Sorry about the time to respond, work has been nuts for the last few days and I don't get much time at home anymore, anyways....

Anti-Flood:
I understand this as built-in to the S5's which seems to have been confirmed earlier in this thread by others. I can also confirm it is indeed not in stock S4's. My car flooded on me once when I had a bad BAC driver and that prompted me to make this feature. The way it works is by suspending injection when the TPS reads more or less WOT and the engine is cranking (pin 3B).

BTW. The ECU ignores the AFM reading while cranking and uses a fixed injector period as a fn(water temp). It's probably the "agressiveness" of this curve that causes some cases of flooding in the first place - longer term project to figure that out better. I have read my owners manual and can say that it does tell you to crank while WOT. What it doesn't say is that your still adding fuel in this case. My guess is Mazda believed that the extra airflow from WOT would lean out the mixture and unflood - didn't work for me.

FCD:
Short answer is this mod functions exactly like an FCD, why its better IMHO, is that its not an additional piece of electronics to put under the hood, it doesn't need any adjustments (and hence can not be adjusted wrong). There have also been a couple of threads on and off about commercial FCD's that have gone defective and not worked or worse damaged ECU's - this can not happen with this mod.

Hailers:
Likewise, lets see if I can word this right as well

Lets start with clarifying some terminology:
When I hear "fuel map" I interpret this as a MAP system with fuel as a fn(MAP or boost sensor, rpm) ie the nice graphs you see from a Haltech/MicroTech.

These cars do not run a MAP system like that - the fueling is mainly based on AFM reading - its a curve that has corrections for various factors (water temp, air temp, atm pressure, etc) applied to it - think carby that's been divided into a single squirt per rev. The AFM of course will continue to read higher as airflow increases (due to more boost) and more fuel flows. Now what I'm not sure of yet, is where the system tops out - I've done some datalogs that would imply it doesn't take much to max the injectors for stock AFR's (next post).

One other related item, to my knowledge, the boost sensor does not play a role in fueling beyond about 1.6psi or so (btw the TPS also plays a role in fuel but only under vac).

What does this mean? You are correct in that the ECU only "sees" 8.6psi. From a fuel perspective this makes no difference to the ECU from above ~1.6psi.

720's:
This is next on my list, probably see something in spring. I've modded the code, just need to buy the stuff to test with (720's and a wideband).

-Henrik

Henrik

Some datalogs (from one of my other mods...), its a little out of context but shows a couple of interesting tech details.

Run showing primary/secondary transition. Fields (after time) are rpm, raw AFM reading, boost sensor, TPS volts, AFM T (C), after IC intake T (C), injector pulse width (ms), water T, battery V.
N332,L,6592,00:03:02.33,2862,125,5.2psi,4.7,46.2,4 1.2,12.0,82.5,13.3
N332,L,6593,00:03:02.34,2922,123,5.4psi,4.7,46.2,4 1.9,11.9,82.5,13.2
N332,L,6594,00:03:02.36,2964,122,5.7psi,4.7,46.2,4 1.9,11.9,82.5,13.2
N332,L,6595,00:03:02.39,3038,121,5.5psi,4.7,46.2,4 1.9,11.8,82.5,13.3
N332,L,6596,00:03:02.41,3108,119,5.5psi,4.7,46.2,4 1.9,11.9,82.5,13.3
N332,L,6597,00:03:02.45,3154,117,5.5psi,4.7,46.2,4 1.9,12.1,82.5,13.3
N332,L,6598,00:03:02.48,3250,114,5.8psi,4.7,46.2,4 1.9,12.5,82.5,13.2
N332,L,6599,00:03:02.53,3304,113,5.7psi,4.7,46.2,4 1.9,12.3,82.5,13.3
N332,L,6600,00:03:02.57,3382,112,5.8psi,4.7,46.2,4 3.1,12.3,82.5,13.3
N332,L,6601,00:03:02.61,3462,110,5.7psi,4.7,46.2,4 3.1,12.4,82.5,13.3
N332,L,6602,00:03:02.67,3528,109,5.8psi,4.7,46.2,4 3.1,12.4,82.5,13.3
N332,L,6603,00:03:02.67,3626,108,5.9psi,4.7,46.2,4 3.1,12.3,82.5,13.4
N332,L,6604,00:03:02.72,3674,107,6.0psi,4.7,46.2,4 3.1,12.1,82.5,13.4
N332,L,6605,00:03:02.73,3788,105,5.9psi,4.7,46.2,4 3.1,7.9S,82.5,13.3
N332,L,6606,00:03:02.75,3812,105,5.9psi,4.7,46.2,4 3.1,6.6S,82.5,13.4
N332,L,6607,00:03:02.77,3860,104,5.8psi,4.7,46.2,4 5.0,6.5S,82.5,13.3
N332,L,6608,00:03:02.79,3956,103,6.0psi,4.7,46.2,4 5.0,6.5S,82.5,13.3
N332,L,6609,00:03:02.81,4060,102,5.9psi,4.7,46.2,4 5.0,6.5S,82.5,13.3

The 60-65% limit is a myth. At 3674 just before the secondaries come on, you can see the primaries at 74%. The cap that people often mention is on the raw AFM reading, at 3800rpm the cap is about 98. From the log you can see at 3674rpm I have 74% and the raw AFM reading is still 107 so there's still some headroom for the stocker to drive them harder.

Here's to redline:
N332,L,9773,00:05:27.36,6516,77,6.5psi,4.7,37.5,49 .4,7.3S,81.2,13.2
N332,L,9774,00:05:27.40,6572,76,6.7psi,4.7,36.9,49 .4,7.4S,81.2,13.2
N332,L,9775,00:05:27.46,6656,76,6.7psi,4.7,36.9,56 .9,7.3S,81.2,13.2
N332,L,9776,00:05:27.47,6840,76,6.3psi,4.7,36.9,56 .9,7.2S,81.2,13.2
N332,L,9777,00:05:27.47,6876,76,6.2psi,4.7,36.9,56 .9,7.1S,81.2,13.2
N332,L,9778,00:05:27.48,6948,78,6.2psi,4.7,36.9,56 .9,6.7S,81.2,13.2
about 78% at redline with a little over 6psi. Notice the intake temp (IC trying to keep up!) and that the airflow doesn't increase from 6572rpm up.

Observations:
At 78% at 6psi there isn't much room before the injectors will max. This is could be where the 10psi limit comes from or is at least a contributor to it. To go beyond this you'de need larger injectors (but no piggyback come spring if all goes well!). btw I'm running with a K&N and downpipe - stock everything else (and 153k miles)

-Henrik

Scott 89t2

yes but normal cranking is at 0. so you could just make it cut fuel for anything over 30%. and under 500rpm or something.

NZConvertible

The S5 has full-range TPS as well as the same narrow-range one the S4 has. The narrow-range TPS only measures from zero to about 10-15% throttle and then reaches the end of it's scale. The full-range one reaches full-scale at 100% throttle. So the S5 ECU can actually tell when the throttle is fully open, but the S4 ECU can only tell if the thottle's open past a certain small opening.

The S5 ECU only cuts the injectors when the throttle is fully open and the key is in the start position. I guess this could work with the S4 if the TPS is at full-scale and a "start" signal is seen. This implies the throttle is at least partly open, unlike normal cranking which shouldn't require any throttle. Is the start signal required as part of your programming?
The terms "fuel map" and "MAP" (manifold absolute pressure) are often confused, but they mean totally different things.The fuel map is just the table of injector pulsewidths vs. load and rpm. Whether the ECU uses a MAP sensor or an AFM for load measurement, it still has fuel maps.
But from an ignition perspective it does. The ECU retards ignition timing as manifold pressure increases just like old distributors do. People seem conviced you need to add more fuel when you exceed 8.6psi with a FCD to compensate for the error, but in fact you need to be retarding timing!

Note that the MAP sensor plays a much bigger part in full-load fuelling on S5's. From the data-log I've seen, the MAP sensor takes over when the AFM maxes out, which happens quite early.

Scott 89t2

if I recall the S5 ecu has both an "on" and "start" ign input into it. where as the S4 only has an "on" input. I'm guessing now that start input is for the fuel cut info? so you probably couldn't do anything to the s4 ecu to know it's cranking.
I guess you could just change the fuel maping for 0-500rpm. 0-30% throttle normal fuel. 30-100 = 0 fuel.

Kenteth

wow... not bad looking at all

NZConvertible

Scott, the S4 ECU does get a "start" input from the ignition switch (pin 3B). It's needed for the cranking-specific fuel and ignition maps, as well as the fuel pump circuit opening relay and sub-zero start assist

NZConvertible

Finally! Hopefully this one can now be buried for good!
Don't forget that the factory mixtures are conservatively rich. These mixtures can be safely leaned out a bit, so there's a bit more headroom in there than the raw data would suggest.

Damn good info.

JOE@FC3S.ORG

--------------------------------------------------------------------------------
You are correct in that the ECU only "sees" 8.6psi. From a fuel perspective this makes no difference to the ECU from above ~1.6psi.
--------------------------------------------------------------------------------

________________________________________
But from an ignition perspective it does. The ECU retards ignition timing as manifold pressure increases just like old distributors do. People seem conviced you need to add more fuel when you exceed 8.6psi with a FCD to compensate for the error, but in fact you need to be retarding timing!
___________________________________________

Also Keep in mind that the infamous "8.6 psi" is only aproximate because the ECU takes into account the atmospheric pressure AND the manifold pressure to determine fuel cut.

For example, a car with no FCD can hit fuel cut when less than 100 ft. ASL at around 7 psi of boost, but NOT hit fuel cut as high as 9 psi at higher elevations ~over 2500 ft. ASL or so) as my car has done consistantly. This is really the only reason I have the stupid FCD on the car. At home, which is around 13-1500 ft. ASL, I never see fuel cut, but I do when I'm near the ocean or other low lying areas.

As others have said, the fuel volume is determined from the AFM, not the pressure sensor.

What I've always wanted to know is if the ECU has the ability to correctly control timing past 9 or 10 psi in the fuel cut is eliminated??

Joe Romeo
(BTW, ASL is Above sea level)

Henrik

[QUOTE]Originally posted by NZConvertible
This implies the throttle is at least partly open, unlike normal cranking which shouldn't require any throttle. Is the start signal required as part of your programming?

Yes it is; pin 3B. You're right about the S4 TPS running out of range before the throttle is WOT, I was a little loose with my use of the term, anyways there's still plenty of room for the feature even with the narrow range TPS only. On a fully cold engine the TPs still reads below about 2v, the cut kicks in around 4v.


The terms "fuel map" and "MAP" (manifold absolute pressure) are often confused, but they mean totally different things.The fuel map is just the table of injector pulsewidths vs. load and rpm. Whether the ECU uses a MAP sensor or an AFM for load measurement, it still has fuel maps.

Key word is "table" - in the S4 ECU there is no table for converting AFM to base fuel injector pulsewidths - its a formula that is computed every squirt. There are corrections applied to that computation, most of which are also formulas (typically curve fits with interpolation between points) and one that's table based but its discrete in nature (no interpolation). The only one of significance during fully warm running is the table based one which is a fn(TPS, MAP and rpm). As I mentioned earlier, the MAP component maxes at ~1.6psi. Ignition is table based (as a fn(load, rpm)) and also has corrections applied.


But from an ignition perspective it does. The ECU retards ignition timing as manifold pressure increases just like old distributors do. People seem conviced you need to add more fuel when you exceed 8.6psi with a FCD to compensate for the error, but in fact you need to be retarding timing!

I haven't been fully through that path yet so I can't confirm or deny whether the stock ECU actually retards timing as a fn(boost). There is an "enabling of timing retard as a fn of other things" when boost starts but beyond that I have yet to see anything directly related to increased boost.

re the 8.6psi and fuel - I think most people are thinking of a MAP based ECU setup which uses the MAP sensor as its primary input. These will of course start running lean the instant you hit the setpoint. I agree with you that really what's needed is additional timing control. Its on the list, but timing control is quite a bit more complex in the stock ECU than fueling and its been well proven to date that running 10psi on the stock timing maps doesn't cause instant engine death.


Note that the MAP sensor plays a much bigger part in full-load fuelling on S5's. From the data-log I've seen, the MAP sensor takes over when the AFM maxes out, which happens quite early.
Hmm, interesting. What are you basing this on, I don't see how you can determine this without being on the inside of the ECU.

-Henrik

Henrik

Yep - agreed on the rich part. Actually if somebody could give me a AFR reading at idle (with no emissions going) I could tell you how rich an AFR the ECU targets.

-Henrik

NZConvertible

Someone posted some datalogs from a S5 TII a while ago. Similar info to what you've posted, but in graph form.

HAILERS

*****Yep - agreed on the rich part. Actually if somebody could give me a AFR reading at idle (with no emissions going) I could tell you how rich an AFR the ECU targets.****

Sorry, that won't be accurate what ever they give you if it's a series four. There's the VARIABLE RESISTOR problem. Do you know one soul on earth that has not adjusted that variable resistor????? I read 13.0 with a decent idle.....but I can make that puppy a 12.0 up to a 14.0 with a twitch of my screwdriver. Both my cars idle best around 13.0 give or take .1 or .2

Oh, that's without the airpump a pumpin'

Yeah. I forgot just why your supposed to add more fuel when the boost is bumped up..........to drown the dang thing with fuel so it won't detonate. Grump.

Henrik

True about the variable resistor, forgot about that - long day... Any other point will do, but I'll also need approx. TPS, boost and rpm or you can give me your variable resistor voltage, I can work with either.

btw. this is what my ECU currently looks like.

-Henrik

HAILERS

Just a note. At idle, fully warmed up, my variable resistor reads 1.65volts and the afr is 13.0 give or take .1 If the electrical plug is removed from the variable resistor, the afr goes to 13.5 give or take .1

razorback

will this help with prolonging the life of my bridgeport?

Digi7ech

iTrader: (1)

Henrik you rock.
This is a great idea and I'm amazed no one else has really done this.

If I didn't just buy a FCD and ECU I would have bought yours.

From what I understood the ECU cut fuel to the rear rotors at a calculated pressure.
The FCD's would then trick the ECU into thinking the pressure is below that number.

I've heard this makes the car lean out a bit over that limit because the ECU still thinks it's running X amount of pressure instead of like 10psi and does not provide sufficient fuel.

I'm a turbo newb so I'm just learning this. Is the above somewhat true?

Would your modded ECU keep adding fuel after the original cut level as if the cut level never existed?