4AGZE Rebuild - worth upgrading or not?

[Bazooka]

I have a job in rebuilding a stock standard AW11 4AGZE engine and was wondering as long as parts like pistons are to be replaced whether it would be wise to upgrade to the later 8.9:1 slugs? The engine is running standard ECU so I am not sure how the new compression ratio may effect the tune? I also have a 175mm overdrive crank pulley that can be used but again with the enigne making more boost will the standard management compensate?
As the job is being done either way I would be interested to know what others thought and whether it is going to be beneficial for the same overall cost?

[oldcorollas]

seems like a good excuse to go to the higher comp pistons (same pin size?), the good rods (92?) etc etc....
also good chance to go aftermarket ECU?

[TooF]

fyi the 8.9 slugs run just fine on an aw11 8.0:1 ecu. spek to drifty midship on these forums, we have recently built him a motor running this configuration and it is going a treat.

[Bazooka]

Unfortunately not my vehicle but if you saw it you would understand why it needs to go as good as it looks. The standard donk is really letting it down. It it were mine I would start all over again and build something very special for it
Aftermarket ECU is unfortunately not in the budget so I was just thinking of other ways (like the pistons) that we may be able to get just a little more out of it and freshen it up a bit.
As I said if I can get away with a bit more compression and more boost from the supercharger on the standard ECU then I think this would be good for it. Anyone see any problems with this?

[Bazooka]

Thanks TooF you got in just before me
Can anyone comment on giving it more boost with the higher comp?

[Duk]

SC AW11s run rather rich at full throttle (into the 10:1 ratios). Seam to run fairly conservative ignition too. I don't think you would have too many issues with the engine staying in 1 piece, but from what I've read of over active knock sensor related ignition retarding, you may not get the very best out of such a set up with going for either a programmable or even a later model MAP sensed computer. Standard air flow meter is too damn small as well.

[Bazooka]

Thanks Plonka.
I'm not worried about the engine staying in one piece but rather just the standard management being able to compensate for the changes. Unfortunately this thing is also automatic so already even more of a slug than usual. If I can get away with doing this and giving it a little bit more pep at the same time then all good and well. We are not looking for any great power increase, just something slightly better then what it was.

[Duk]

I can recommend bigger AFM and a bigger throttle body. They made a noticeable improvement on my MR2 even with standard SC pulleys, so I think your set up would be in desperate need of them (stock 1s are just too small).

[YLD-16L]

I can recommend bigger AFM and a bigger throttle body. They made a noticeable improvement on my MR2 even with standard SC pulleys, so I think your set up would be in desperate need of them (stock 1s are just too small).

Whilst they are a restriction (particularly the vane type AFM) they are still capable of flowing enough for in excess of 150kw @wheels.

Stock ECU and AFM are happy up to about 15psi also without needing to do any changes.

Getting an SC12 to produce the above figures might be a little more work

[Duk]

Whilst they are a restriction (particularly the vane type AFM) they are still capable of flowing enough for in excess of 150kw @wheels.

Stock ECU and AFM are happy up to about 15psi also without needing to do any changes.

Getting an SC12 to produce the above figures might be a little more work

Sock TB and AFM provide a nice 4"Hg (damn near 2psi) pressure drop at full throttle above 6400rpm with standard SC pulleys.
Why give away power or even bother trying to get the SC to pump more air when it can't get enough in standard form? 3SGTE (and probably a 3SGE) AFM is 25% bigger in cross sectional area and a 4AGE TB has a 5mm bigger bore .

[oldcorollas]

does the bigger AFM give the correct signal for all loads tho?
being bigger, and still having 0-5V output, would mean that all the load readings are low... and reduce fueling.. no?

[Duk]

does the bigger AFM give the correct signal for all loads tho?
being bigger, and still having 0-5V output, would mean that all the load readings are low... and reduce fueling.. no?

No. I used a the Jaycar digital fuel adjuster to get all to work correctly.
The standard AFM runs out of resolution quite early (did the testing and bigger AFM upgrade ages ago so can't be more specific).
AFM signal seamed to have very little to do with actual air/fuel ratios when at full throttle. Using the DFA to change the high load signal did very little for AFRs.
AFM signal is definitely a major input for SC switch on and low load AFRs (would run rich and cruise with the SC engaged until tuned).
I actually used a 2.2ltr Mazda AFM housing with the 4AGZE circuit board inside it, but the Mazda and 3S housings are the same size.
BTW, signal is a dropping voltage and is about 3-2.8 at idle going down to just above 0v at full scale.

[oldcorollas]

ahh ok, cool

[YLD-16L]

^^^^^ lucky that post came up as the impression was it was a plug and play deal from only reading this thread.

Good info.

[oldcorollas]

now.. abotu that turbo..... and some 550cc injectors.. and and...