7m boost cut

[Bored?]

I'm curious about how the fuel cut works on the 7m-gte.

Does the ECU have an actual boost sensor somewhere, or does it calculate it from the air-flow meter?

What type of signal comes from the MAF and/or MAP sensors? (Is it just a simple analog voltage reference, or something more complicated?)

With the answer to that in mind, which fuel-cut defenders will work with the 7m ECU?

(And before someone jumps in and says "FCDs are bad", it would be used in conjunction with a generic piggyback computer.)

[Bored?]

Just found this thread on 7MPower.co.uk which seems to answer the first question:
http://www.novogate.com/exco/thread....hreadid=103821

Apparently it is primarily airflow related, and therefore not really a boost cut, but a peak airflow cut. This is good news, because it means that leaning out the overly rich stock tuning with an AFC will also have the side effect of raising the boost cut.

[doobs]

The easiest way to raise the boost cut on the 7M is to do the lexus mod, theres lots of documentation around on it, works fine for me...

[Bored?]

Good info on the AFM in this thread:
http://www.toymods.net/forums/showth...ight=lexus+afm

Although the technical writing is unclear and needlessly repetitive. (Like he wants to make something very simple sound overly complicated). Here is what I understood from reading it:

1) Use a larger 1UZ AFM housing (causing lean mixture)
2) Use larger 550ccc injectors to compensate (causing rich mixture)
3) Fine-tune with adjustable air passage in the lexus AFM
4) Using larger injectors causes the ECU to learn to compensate by reducing injector duty in order to lean the mixture. (due to closed-loop mode)

This seems like a pretty crude approach, but then, most people with 7m's are on a tight budget anyway. (After paying for all the BHGs)

Would be smart to use an AFC and tune it with a wideband sensor if going down this path.

[doobs]

The process is very simple, I think the extended description is for those who must know how things work exactly...

It may be crude, but it works well, and the parts can be had quite cheap. As far as I know most of the lex afm's dont have adjustable air passages, you fine tune with an safc and a wideband like you said...