Stagea Exhausts

[EGA41T]

so why does my engine back down when the boost is up too high and i plant the foot down?

[beastien]

I'm pretty sure it's the ECU thinking there is too much airflow, which is calculated by the air flow meter, therefore it goes into R&R.

SK can explain it better.

[FLYSLY]

So basically he needs a tune then

[AlexCim]

beastian - correct

flysly - yes, afm voltage bender like a dfa/safc is fine for this

[fergo308]

Wolverine: yeah,they use an afm to control mixtures. on the neos though,there's a map sensor that's there to monitor boost,and the ecu then triggers the cut at the level I mentioned earlier,as reported by my the peak hold on my digital boost gauge. if Sk can sucessfully dispute this,great,maybe I'll learn something.

Alex: if the cut is actually the AFM hitting 5v,how do you guys with larger turbos handle the problem? are you running Z32 AFMs? guys with far more power than my car makes have been running the std AFM for a long time and still have plenty of resolution left in their airflow maps.

I've felt an AFM 5v cut out before on an S14 I owned a while back,and it's way more savage than what the neo does at EXACTLY 1.0kg/cm3 of boost.

it's a limiter in the ecu. anyone who doubts this is welcome to meet me somewhere and experience it for themselves.

Justin...

[AlexCim]

It is not the AFM maxing out but its the AFM registering an AF that is too high for a specific rpm/load.

THis is based on the std tune which is given.

What a DFA/SAFC does is "bends" the AFM voltage to trick the ecu in thinking there is a lower air flow than there is (this is OK as the std mapping runs rich anyway). So there is a certain % gain you can have with an AFM bender. Basically, these electronic units are variable resistors with multiple load points

[Sydneykid]

Wolverine: yeah,they use an afm to control mixtures. on the neos though,there's a map sensor that's there to monitor boost,and the ecu then triggers the cut at the level I mentioned earlier,as reported by my the peak hold on my digital boost gauge. if Sk can sucessfully dispute this,great,maybe I'll learn something.

Alex: if the cut is actually the AFM hitting 5v,how do you guys with larger turbos handle the problem? are you running Z32 AFMs? guys with far more power than my car makes have been running the std AFM for a long time and still have plenty of resolution left in their airflow maps.

I've felt an AFM 5v cut out before on an S14 I owned a while back,and it's way more savage than what the neo does at EXACTLY 1.0kg/cm3 of boost.

it's a limiter in the ecu. anyone who doubts this is welcome to meet me somewhere and experience it for themselves.

Justin...

A quick explanation on “boost cut” and R34’s / Stagea S2’s;

1 The ECU cuts NOTHING, fuel still flows and the ignition still fires, so calling it a “CUT” is 100% wrong.

2. The R34/S2 ECU is a bit smarter than the previous versions, but like them, it still has Rich and Retard mapping that it reverts to when it detects something amiss. For example if the throttle position and the rpm don’t agree with the AFM voltage the ECU hops into R&R mapping.

3. The ECU doesn’t care about boost. If you fit an SAFC/DFA (or equivalent) you don’t get R&R mapping. If the ECU cared about boost then fitting an AFM voltage bender wouldn’t work

4. Combining #2 and #3 above, you use an AFM voltage bender to realign the AFM voltage with the throttle and rpm. So the ECU thinks that all is well and doesn’t get into R&R mapping.

I hope that clears up the fallacy of boost cut and Skylines/Stageas.

cheers

[fergo308]

fair enough. so.....what's the MAP sensor there for? purely for the optional gauges that aren't an option on the stagea?

while we're talking the whole panic mode thing in the ecu,I've seen that before as well,at about half as much boost as I currently run,as I had too much base advance dialled in at the CAS (thanks CRD...). if it detects pinging,it winds the boost and timing back,and goes rich,as you've described.

that isn't what happens at 1.0kg. it CUTS.

like I said,you're more than welcome to experience it for yourself,and then talk to me about it.

Peter at Advan refers to it as a boost cut,and was adamant about why it's there,and why they don't run a std turbo above it.

I may be a newbie to you guys,but I've been around cars (nissans and otherwise) for quite a while now,and actually know a thing or two. being that I'm also a qualified mechanic,I reckon there's a chance that I have at least half an idea about what I'm saying.

if I'm not sure of something,I'll say so.

if I say it's a cut,there's a VERY good chance that's what it is.

anyway,the offer is there mate,and I'd actually not mind your input.

I'll be putting my car on the rollers on sunday. if you want to meet up and have a chat about this,pm me,and i'll let you know where I'll be.

Justin...