How Much Would You Charge Me For a EPROM To Gid Rid Of Boost Cut?

[rico05]

I just need a new chip that gets rid of boost cut. Just something to tide me over till I can get a Power FC.

[redamnavit]

Now someone will definitely correct me if I'm wrong here, but I'm pretty sure the only thing standing between you and a higher boost is the wastegate.

[rico05]

IIRC ECU has fuel cut at 9psi. If it is only the w/g, then no biggie. I have an HKS one ready to go on.

[Notchbackca]

yeah it bucks like a pissed bull when you hit boost cut, I can whip one out for you if you just pay for the chip/shipping, all together it would probably be like 10 bucks

[rico05]

Bling

[email protected]

I need to run a buddy of mines lightly modded LT1 (94 Z28) and we all think that I will win, but i need to be at 12psi at least me thinks...

[nocwage]

9psi fuel cut eh?I wonder if mine is modded.. it boosts to 10-11psi peak and i've never had a fuel cut..

[WeldingHank]

do the HKS Fuel cut defenders work with the CA?

[s13conv]

Are the ecu's already EPROM and socketed?

[Notchbackca]

fuelcut defender guards against fuel cut(afm maxed out), not boost cut(ecu restriction)

[datsunboy]

whats the exact parameters you change in the ECU for boost cut?...how the hell does it now how high its boosting anyway?...no map sensor or anything????

[rico05]

So can anyone make me one? I am gonna give it a try and see what happens w/ my new wastegate. I have no rev limiter, so who knows what else is wierd about my car...

[Notchbackca]

yeah it bucks like a pissed bull when you hit boost cut, I can whip one out for you if you just pay for the chip/shipping, all together it would probably be like 10 bucks

^

and boost cut simply compares the amount of air going through your afm and your rpm to a table, if its to high, it will let you know

[rico05]

So how do I pay you, and when can I get it;)

[Notchbackca]

I am back at school now so I can program em', if you just have one shipped to me, I can just pay for mailing it to you... should't cost much, its just the electronics stors have a tendancy to overcharge for shipping

email me and I will send you my mailing info

[float_6969]

I think he's got the Power FC now, but I could be wrong.

[nocwage]

I thought the boost cut only comes on when the MAF's voltage reading is getting close to it's maximum of 5v.. which if I'm correct would mean disabling boost cut is guaranteeing a lean out condition.. i.e. KABOOM.If you're hitting that point I'd suggest a Z32 MAF and the appropriate modifications to accomodate it.

[float_6969]

I don't believe so. There is a difference between maxing out the MAFS and boost cut. As stated earlier in this thread, there is a relationship between rpm, throttle position, and the air flow that will allow you to calculate boost. Based on this table that is stored in the computers memory, if the boost exceeds aprox 9psi, it will shut the fuel off to the motor. It creates a "bucking" sensation, as the car will jerk back and forth. Maxing the MAFS out won't really show any effect other than a lean condition.

[nocwage]

I read it here.. Doesn't mean it's right but it makes sense to me..

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

[WeldingHank]

seeing as the car doesn't have any type of MAP sensor. i don't see how boost could affect the point at which the ECU cuts fuel. it makes much more sense that maxing out the MAF triggers a fuel cut. the ECU isn't reading pressure ANYWHERE, so how does it know?

[rico05]

There is a set varible in the ECU for MAF voltage. When the actual voltage breaches that point (CA18DET ECU is 5V) the ECU kills the fuel. At 10psi the MAF sees enough air to trip the MAF past the ECU set limit. Just read the article.

[WeldingHank]

There is a set varible in the ECU for MAF voltage. When the actual voltage breaches that point (CA18DET ECU is 5V) the ECU kills the fuel. At 10psi the MAF sees enough air to trip the MAF past the ECU set limit. Just read the article.

i think i pretty much just said that. but, with any nissan MAF, the max voltage is 5 volts. its size dictates how much flow it takes to get it to 5 volts.

[Notchbackca]

hank you aren't quite catching on

there is a ECU set limit for MAF voltage that causes BOOST CUT

the 5v max output on maf causes fuel cut

its that simple

[rico05]

Emailed you Notchbackca

[T88lexus]

just make the boost cut turn on at 5.00 Volts (the MAF Max)I just give it a maximum value. very simple. (FF=MAX)

[slw240sx]

"boost cut " is there for a reason, if you are hitting it then you need to fix stuff other then trying to reprogram... i was hitting cut on a z32 maf , also if you want to run 10+ psi you need bigger injectors as your running max inj duty cycles and risking fuel starvation.

[rico05]

Even with a SFAC Jon?

[T88lexus]

with 10psi.. with ca T25.. my wideband runs about 11.8-12.1 .. great A/Fwith 10psi .. with Sr T25 ..my wideband runs about 12.3-12.7.. NOT SAFE on daily drive.(15psi with SR20 T25 runs 12.9ish waiting to hear the BOOM!these are without safc. with safc you can fine tune it somewhat to how you want to run on your air fuel mixture.

injector duty cylcle at 87.5 MAX on CA T25 on 10psi, with sr t25 is 92.7 MAX.

running those turbo from dyno experience , yes you do not need bigger injector unless you are going to go upgrade on your turbo.

but with SR T25 is must for fuel pump..or get a DSM fuel pressure regulator and put them on( they runs 45psi FP instead of ca is 32psi I think).. not bolt on but it was easy enough

[WeldingHank]

hank you aren't quite catching on

there is a ECU set limit for MAF voltage that causes BOOST CUT

the 5v max output on maf causes fuel cut

its that simple

i read that whole article above. and no where does it mention seperate boost and fuel cuts. it seems that fuel and boost cut are one in the same. which makes more sense.

[biosehnsucht]

If the ECU hits the MAF reading ceiling it just shuts down fuel because better to momentarily lean and then lose all power than to risk leaning continuously since it can't know how much to put in.

the 'boost cut' as most call it is a table of values that correspond to RPM points (I don't think throttle position matters, I remember it being one dimensional) at which if RPM = X and MAF flow > table[position x] it decides you've too much boost and cuts fuel also

Normally won't see that unless you've got something spooling faster and/or much higher than stock, since this table is set up as a safety net for "something must have gone wrong to spool so fast/high" basically.

I'd imagine setting all the entries to 0xFF (or 0xFFFF, don't recall if its 8 or 16 bit) would effectively nullify it since if it activates so does the MAF limit, and if you hit that you don't want to keep going and lose the motor.

[slw240sx]

i didnt need a SAFC we never got to the tuning part of the car before i lost the rings. this time around i have a wideband o2 and acess to multiple dynos and tuners that are working with us on many differnt rom tuning ventures like mustangs kadet's sr's.

we will be doin street tuning and tuning on both mustang and dnyojet rollers. i now have acess to alot of cool things now that my parnter is working in a turbo shop and the owners are really intrested in our cars and the nissan turbo scene.