one step closer, removing boost cut

[Notchbackca]

anyone know how to remove boost cut? or what the address is for it in the Bin file for the ROM?

[biosehnsucht]

does the CA ecu really have "boost cut", or is it just hitting the metering limitations of the stock MAF?

[Notchbackca]

its got a boost cut... I have Z32 maf... I don't think you could max that out with the stock turbo even if you used it as a hair drying while running full boar with the, and HAHA I found it! tomorrow I hit 7 grand

[biosehnsucht]

ooo ooo fill us in! (if it works)

[slw240sx]

leave it be , its there for a reason, and if your hitting it, then you need to do some adjusting.

[Notchbackca]

let me say this one more time, its not fuel cut, its boost cut... VERY different

[Notchbackca]

HOLY crap its fast, anyways since I have a 3 inch turbo back I was boosting 10lbs instead of 7, long story short, if you want to run more than stock boost you need to adjust boost cut(you can't get rid of it without standalone)

[Nismo1182]

You can get rid of it with a chipped ecu :-)

[slw240sx]

what do you think its cutting??? sure as hell isnt spark

[Nismo1182]

bingo we have a winner, it cuts fuel. Riddle me this, how can you cut boost?!

I think its set that if the stock ecu sees over 12 psi, it cuts fuel. It doesnt not cut boost, you cant cut it back to less than 6/7.

[slw240sx]

it cant measure PSI. it can only measure air flow. therfore once the MAF reads too much air it will cut fuel. either that or it goes by fuel injector duty cyle but i think its MAF related.

you can remove it i belive, but if you do nothing but remove it because you keep hitting fuel cut at a certain psi. well then you might as well pass that motor to someone who would treat her right. cause your going to kill her fast .

[Notchbackca]

PLEASE READ MY POSTS BEFORE TRYING TO PROSECECUTE MEwhat part of its not fuel cut didn't you catch, or perhaps the Z32 MAF slipped by you, AND I NEVER SAID IT CUTS BOOST, BUT ITS STILL CALLED BOOST CUT

actually "boost cut" CUTS SPARK, fuel cut is from maxing the AFM out, again I have a Z32 maf and a stock turbo... it can't max my afm, esspecially at 10lbs of boost, which is just having the wastegate hooked to my compressor outlet

also you can't get rid of boost cut with a chipped ECU, you can however push it back to where it doesn't interfere, but its still there

and one last note, boost cut is based of FLOW, PSI MEANS NOTHING

http://www2.osk.3web.ne.jp/~t1....html

and just incase you still haven't got it "BOOST CUT" AND "FUEL CUT" ARE TOTALLY DIFFERENT, AND ARE CAUSED BY TOTATLY DIFFERENT THINGS

"well then you might as well pass that motor to someone who would treat her right. cause your going to kill her fast ."its YOUR engine I fear for because obviously you don't have any understanding of it, and another thing, I ALWAYS WATCH MY A/F and trust me I am in no danger of leaning out

[slw240sx]

Firstly - Background

Air Flow Meters (AFM), a.k.a Mass Airflow Meters (MAF):

The basic function of any ECU is simple. Calculate the correct amount of fuel and ignition advance required by the engine at any time. To make these calculations it needs to sense how much "load' the engine is under.

The primary load sensor on the Nissan ECCS ECUs is the Air Flow Meter. It is the ECUs biggest asset and also it's achilles heel (from a performance viewpoint).

The AFM measures the true mass of air entering the engine. Since mass of air entering the engine is known, determining the mass of fuel required for an appropriate Air Fuel Ratio is a straight forward calculation. This also means the majority of modifications will not require a retune, unlike MAP based systems.

Unfortunately the standard AFM can be a considerable restriction in the intake. A 50mm diameter is not a large area for a turbo to draw through. AFMs also have a set operating range from 0-5V, representing a flow of air from 0 to their max rating. 5V on a CA18DET AFM is equivalent to enough air to make around 200hp. 5V on a 300ZX TT AFM is enough for over 500hp. Fortunately, retuning for a larger, less restrictive AFM is possible.

Once the CA18 ECU senses the AFM is at its limit (ie at or close to 5V), it will cut fuel to protect the engine. The dreaded boost cut. Or more accurately, Air Flow Cut.

Once the Airflow meter is at 5v, any increase in flow will still result in a reading of 5v, as the sensor is at its limit. The ECU can no longer calculate the correct amount of fuel, so it shuts down the engine to prevent a lean out. Once the AFM reads below 5v, the ECU will inject fuel once again

from http://members.optushome.com.au/silent8ob/ecu.htm

im not worried about you maxing out the turbo or MAF , cause its not happening. im worried about you maxing out your injectors and melting pistons.

[Notchbackca]

wideband O2... I always know what my A/f is, and I have no plans for increasing the boost on my stock turbo, its as low is it will go with my setup

If you want to make over 200whp I'm afraid boost cut has to go, when I get my new manifold and turbo on my car I will be running 550s

[slw240sx]

trust me i know all about 200hp and boost cut, i battled it for the last few weeks my car was running till the turbo crapped out.