Redtop 3SGE mystery porting. (and ECU question)

[RomanV]

I have aquired a damaged redtop 3SGE that I will be rebuilding.
I have the head over at Lynn Roger's workshop, they are checking it for me. (it turns out its sweet BTW )
While doing this, they noted that it has had a rather extensive port and polish job done to the head, presumably while in japan. I thought this was a good thing, until I read Redmists comments about porting in the thread in the FAQ.
I mean the redtop makes peak torque at 6000rpm or so already, why would they do this? I would imagine the porting would already be 'tuned' to flow efficiently at high RPM anyway.

It seems weird that they would do all of this work, when the engine is relatively stock apart from that. Could it possibly be a factory porting job?

I have been told that this will effect the volumetric efficiency of the engine, which I understand. However I have been told that this could possibly mean that the factory ECU will not be able to cope.
Has anyone else had experience running a ported head, on the standard ECU? I know it will vary from ECU to ECU, and engine to engine. I just want a general idea.

I thought that since the car runs an AFM, it would just sense that more, or less air was entering the engine, and alter the fuel ratios to suit?

Also I thought that some ECU's have a limited ability to 'learn', and generate revised fuel maps to suit the fuel that was used, etc. Like I hear that the altezza boys have problems with the clever ECU overriding, or 'tuning out' their aftermarket fuel management computers.

Well thats what I read on one of the altezza forums, anyway.

Regards,
RomanV

[Mr Revhead]

no toyota ecu that iv ever heard of (thats avail to the public) is capable of "learning" if some one has proof please share

it wont be a factory port job.
the bottom end may have lunched itself, or they found the head surplus to requirements... anything may have happened!

the problem with a ported head (in relation to your question) is it can vary so widely, there will be heaps of heads out there that have been played with and work fine on stock ecus, but yours may not. or it may.
talk to them a bit more, lyn rogers knows his stuff, and they have played with those engines before

sounds like they are altering one thing, and the ecu compensates for it....

[RomanV]

Apparently, someone was running an aftermarket fuel computer of some sort.

The standard ECU tries to attain a 14:1 air/fuel ratio, and the aftermarket computer was running the engine leaner than this. (I would assume!) After a few weeks, the ECU had 'tuned it out', and was running at 14:1 again.

Or so the story goes! I read it on the NZ altezza club forums. I will try and find a link a bit later on.

EDIT: This is only my recollection of the story, I will confirm how much I am hallucinating when I find the thread.

[RomanV]

it wont be a factory port job.
the bottom end may have lunched itself, or they found the head surplus to requirements... anything may have happened!

Nah I know what happened to the engine. It ran lean and melted a piston basically. Courtesy of running NZ 96 (if not 91! ) on an engine with an aftermarket fuel computer, which was aggressively tuned for 100 octane in Japan.
Well, that seems to be the case anyway.

AAAAAaannd. I couldnt find the link on the 'tezza forum, it seemed to be down. But now that I think about it, they were probably fiddling with the sensors (perhaps the AFM) to make it run leaner, and the ECU had fully compensated for it, after two weeks or so.

[Dell'Orto]

Well, it just means you'll have to run big ass cams as well as a MoTeC

[RomanV]

Yeah, wouldnt that be a tradgedy.

[dodgy]

burnt out a piston eh?
guess what ive just picked up off trade me.
a brand new set of altezza pistons! im stoked!
they have a slighlty higher riser in the top of the piston, which of coarse gives the higher compression. (comparing them to the red top 98)

[RomanV]

Yeah I saw those on trademe.

However, I will be using .5mm oversized pistons, as the block will be bored out slightly.

So that will make my displacement..... 2010cc's.
Woohoo! 12cc's increase.
If I can assume that max hp will increase by the same amount, I will gain a colossal..... 1.1 hp.

And Mr Dodgy, I believe you promised pics a while ago!

PM me if you dont want to put them on the forum.

[jasestu]

Regarding the "learning" ECU comments, here's a few excerpts from this thread on the AltezzaClub of NZ/Australia forums.

The SAFC intercepts the voltage signal from the MAF & inputs a 'false' signal into the ecu. The stock ecu will compare data from the MAF & the outputs from the O2 sensors and if those don't match up, it will modify the modified signal from the SAFC to ensure that all parameters are as per standard spec. Voila! It has just tuned out your SAFC.

i agree with RS200AT... our stock ECU has a closed loop target ratio of 14.7 up to 50% throttle opening. u culd try with de SAFC II to richen the ratio but chances are that the car will be forced to run open loop when it cannot correct the ratio any further, and u will face fuel economy problems coz i suspect de stock ECU retards timing to play safe once it starts to run open loop....

[sergei]

The toyota ecu can learn in a limited way, if its within 20%(?) of original map (and if not it will run open loop), it can adjust ignition and fuel maps... according to this:
http://www.autoshop101.com/forms/h44.pdf

[jasestu]

The toyota ecu can learn in a limited way, if its within 20%(?) of original map (and if not it will run open loop), it can adjust ignition and fuel maps... according to this:
http://www.autoshop101.com/forms/h44.pdf

Useful section that Technical one on autoshop101.com, plenty of
good reading material for these rainy afternoons...