Fuel cut question, indepth..

[Dylan JZ]

Right so my plan when my 1J is done was to have jdm 440's installed immediately.. This is because I have both the neo AFC and a profec B to regulate.

However I wanted to tune for up to 17 psi, obviously I'm going to hit fuel cut before that and was previously going to use a Greddy BCC, but now I'm reading and reading and see where ppl sa its a danger.

"Could run too lean and is a timing bomb" are amongst the comments.. My question to you guys as a whole is what is the truth. Not what you think, rather what you know.


Is this BCC (aka FCD) an alright tool, or useless based on safety for the engine?

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Or should I do this AFPR deal from DM and do what BlackMKIII is doing by increasing fuel press?

This is bugging me pretty bad and none of the other threads answered my question even close to directly.. Perhaps this could serve as an end to these threads if a straight answer can be given.

 

[Erkenz]

You should have no problem using a BCC, it's a great tool. Just make sure to use a wideband gauge to make sure you're not tuning it lean. With 440's though, you shouldn't have a problem.

But the best way to avoid hitting fuel cut, is to get AFPR and up the pressure in the line, while using afc to tune it to just below fuel cut. You can raise the boost high without hitting cut by doing this.

 

[Dylan JZ]

You should have no problem using a BCC, it's a great tool. Just make sure to use a wideband gauge to make sure you're not tuning it lean. With 440's though, you shouldn't have a problem.

But the best way to avoid hitting fuel cut, is to get AFPR and up the pressure in the line, while using afc to tune it to just below fuel cut. You can raise the boost high without hitting cut by doing this.

Thank you for your response.. Please, if anyone else has an intelligent answer such as this based from experience, chime in at any time.

I know some of you guys, if not quite a few are using one of the two methods. Dont hesistate to post, as this just isn't for me, this is for those in the future with the same question and hopefully they wont be left with dead ends the same as I was prior to this thread.

 

[Dylan JZ]

Well. Finally I found some info on some sites from the UK as well as the US.. I've concluded that from experiences of those using them, that these BCC's and FCD's are rather dangerous.. Even to those who know exactly what they're doing, perhaps even tuned correctly. Tricking the ECU can have too many anomalies in the system to ensure a trouble free system including but not limited to boost leaks/ running lean etc. Beyond that, there were other explanations and problems such as timing I believe, however I did not fully understand them. I think just this info should suffice though..

Once again, there are those who do not see problems, but from my experience here today I saw many more posts about bad experiences than good.

Simply put, I now concur that the AFPR and proper tuning is safest way around this problem. Other than that perhaps a tuned ECU (Ie. Mines) or a full stand alone seem to be the other expensive yet neccesary means to do so beyond an AFC + wideband/datalogger.



The AFPR method is a little over $100 more than the HKS FCD and for the piece of mind to keep your engine running fine with no worries, I believe its completely worth it. I will be taking this route no questions asked..

Thanks for reading.

 

[250sx]

nice writeup.