Major Flat Spot

[fane]

nps mate.

thanks for the help.

ps. i spoke to my mate and his wolf uses the map sensor so thats why he isnt maxing out.

[ix9]

Thanks for your support!!!  :wassup:

 

 Your car is obviously stock?

Ahaha. Nah man, I'm a firm believer it was made that way for a reason.... If it were beneficial, I'm sure the crazy japanese would have thought of it and pioneered it a long time ago :|

Far from stock my car is

[The Alchemist]

Hi, I have a similar problem, working on a car today , dyno graph shown, its a RB20 with a front mount and big bore and a greedy BOV ext venting and apart from that quite stock. Fuel system has been checked through to the injectors and Coils are all good with new spark plugs. Inlet manifold has also been removed and new gaskets fitted right through...most were leaking ...

TURBO UPGRADE:

T3 core with a TO4E comp wheel in a TO4B comp cover 0.6 A/R, stf turbine housing machine to fit T3 core steel turbine wheel , 360 thrust.

Thing is car makes boost ok, but a bit laggy. And where there is boost > torque usually follows in line. As you can see by the dyno graphs torque doesn't follow until very late in the rev range .....whats up ?

:Oops:

[Cubes]

It has absolutely nothing to do with the AFM Maxing out.

If the AFM were maxing out you would have a violent fuel cut while hard on the throttle that makes you shiet your self.

Its the typical Stock ECU playing funny buggers with ignition timing.

Its time for you jump on the PowerFC bandwagon.

Or if you want to loose your sequential injection (that improves fuel economy and burn efficiency) go the Wolf3D.

[strutto]

Ahaha. Nah man, I'm a firm believer it was made that way for a reason.... If it were beneficial, I'm sure the crazy japanese would have thought of it and pioneered it a long time ago :|

Far from stock my car is

Yeah that's a fair point... Those crazy japs do think of lots of wierd ass things... I think the idea is sound in theory, but in practice probably wouldn't work real well...

But I don't agree with your point about cars being made a certain way for a reason... Manufacturers have to juggle all sorts of things like noise, reliability, fuel economy, etc when they design a car... We are talking about performance only here... Anyway if you agreed with your own opinion your car would be stock!

[strutto]

It has absolutely nothing to do with the AFM Maxing out.

Why does it read at 100% then?? Serious question, not having a go...

If the AFM were maxing out you would have a violent fuel cut while hard on the throttle that makes you shiet your self.

Thats the fuel cut right? Not the overboost protection?

Its the typical Stock ECU playing funny buggers with ignition timing.

Which it does based on the values coming from the AFM (and knock sensors) correct?

[Cubes]

hehe well that will teach me for not reading all the posts.

EDIT: Its interesting that you said you are maxing out the AFM but your AFR's are fine.

My experience is when you max out your AFM you also max out your injectors at the stock fuel pressure. Maybe thats just the little ol' R32's.

[Robo's]

It has absolutely nothing to do with the AFM Maxing out.

 

If the AFM were maxing out you would have a violent fuel cut while hard on the throttle that makes you shiet your self.

 

.

This is what i get when i turn up the boost. A violent fuel cut off which makes me jolt forward.

[Cubes]

If the Z32 was to work with the SAFC the only way I could see it working with the stock ecu load/ign & fuel maps is by either bumping up the fuel pressure or using larger injectors.

If you were to use the stock injectors and fuel pressure it would defeat the purpose of using the Z32 as you would have to raise the AFM voltage (via safc) for the afr's to come back in line as the car would be running lean.

I would then be interested to see if the closed loop O2 mode freaks the ecu out as it would have to pump in fuel to make the afr's right.

The O2 sensor only trims the map to get the afr right.

Its got a base map that is fairly close to being spot on.

So Using a Z32 would be as simple as selecing i.e HW 2 IN and HW4 out?

Would that setup adjust the voltage back to suit the RB AFM calibration?

Or would you have to select HW 2 in HW 2 Out? (HW 2 is just an example)

Would be interesting to fiddle with. I've pulled the SAFC out of mine now.

[The Dan]

check for a problem with your knock sensors. They'll kick you in the arse when they change your timing curve.

[fane]

i havent knocked at all so far...showing on the safc...

now im really confused on what to try...hehehe

hmmmm....whats everyone reckon.....want me to try anything then let you know?

[mabru]

I don't remember the exact number the SAFC uses to id the Z32 AFM. I know it's as easy as saying "HW4 in HW1 out" or something like that. Of course you will need to adjust your fuel map accordingly, but the SAFC will allow plug n' play operation of a Z32 AFM.

Again, I'd have to dig up the documentation to find the specific codes to use.

-Matt

[fane]

i hunted down the manual and found out that for you to run a z32 afm on a r33 you have to have the in on HW2 and the out on HW4.

Currently mine is on HW4 - HW4 and they show how to put it on a SR20 so i presume the same applies to the RB25

Here is the page,

[Cubes]

Does it change the resolution or simply manipulate the signal to read as if it were running the origional sensor?

I know there is a benifit with changing the AFM's on the S15 or example as a friend has one and the afm reduces to around 40mm or so.

Therefor using a Z32 or RB afm with its 80mm diamater will increase turbo efficiency.

Only time will tell.

After exams I am installing a SAFC in to a S15.

Hopefully he will want to use an RB AFM so I can test it and see the improvement from a ~40mm afm to a 80mm afm.

[fane]

i dont know joel....it doesnt explain the manual i dont think but i would say that it just changes the signal so that the ecu thinks its a normal afm but is getting the right readings in proportion to the change....

as far as i understand the safc is there to trick the ecu by sending it wrong readings with everything....so that the ecu puts in the right amount of fuel and crap like that.....am i right?

[Cubes]

See thats the thing I'm having trouble with.

The SAFC doesn't change the maps its only changes the AFM signal.

So if you use a higher cfm resolution Z32 AFM & setup the SAFC so it knows its reading from a Z32 and outputs as if it were a RB AFM (assuming thats what HW2in HW 4 out means) then it would defeat the purpose of the AFM swap, when the Z32 AFM is reading say 4.4v the safc will be sending a signal to the ecu of 4.9v or there abouts as that is what the RB AFM would have been reading.

If the car was origionally running rich then this may buy you enough resolution to scrape in as you will only have to make a slight adjustment to the top end where it runs rich.

But you may still have problems in the mid range with fueling as the map there is generally leanish as it is.

If you have the SAFC setup so it doesn't change the signal back to a RB AFM resolution then it also defeats the purpose as the car will be running lean (HW2 IN HW2 OUT).

You will have to richen up the fuel everywhere by approx 13% or so which raises the AFM signal back up to where the RB afm was, and your back where you started 5v again.

So ... The only real answer is to use the Z32 setup the SAFC to (HW2 in HW2 OUT) and increase fuel pressure 10% or so (Or use bigger injectors) then do the fine adjustments with the safc.

This should work quite well and give you a considerable higher power level before the AFM max's out.

It all depends on if the HW2 in HW4 out really does manipulate the signal to return it to the origional voltage.

I.e in the S14/S15's case of running a restrictive AFM, the advantage of changing to the larger 80mm afm is obvious and is not done so for the extra resolution.

Come on some one.. I'm finding this interesting, some one have a fiddle.

[Robo's]

So when the standard AFM maxes out, how exactly do you know its doing it.

Im getting 100% air flow just after 5000rpm, my missing is at 4500rpm, so this means the AFM is not my problem?

[Cubes]

If it reads 100% then it is maxing out. BUT maybe the SAFC has a type of afm cut defended that holds the voltage at 5v and won't go over which avoids what ever the ecu does when it hits the ~5.1v.

Only problem with this is the ecu has reached the limit of the ecu's maps and uses the same injector duty cycle & ignition for any airflow above.

Eventually that fueling setup for x airflow is going to start to lean out dangerously.

The missing could be a lean mixture having trouble igniting?

[fane]

PFC will fix my problem if i keep my stock afm? or will i need the z32 afm plus the pfc?

[Cubes]

PFC will fix the problem with the stock AFM providing you make under around 220rwkw as that is apparently where the stocker AFM begins to run out of resolution & max's out.

I'm unsure if the PFC can be mapped beyond the AFM, most ECU's can.

Z32's are fairly cheap these days & the plugs are easy to come by.

But it all adds up.