Unique to the 7A-FE were two-layer metal head gaskets, and a two-piece oil pan (one piece of aluminum alloy, the other of steel; the upper pan was secured to the cylinder block and transaxle housing). The crankshaft and connecting rod specifications were modified to match the longer piston stroke and higher power output of the 7A-FE engine, and the pistons were made more rigid by modifying the oil return from the slits to 8 holes.
The valve details were also changed to match the improved performance. The intake diameter was increased from 30.0 to 31.0 mm, the exhaust kept the same size at 24.5 mm, and the lift increased from 6.6 to 7.6 (both intake and exhaust).
In previous engines, engine coolant from the radiator flowed to the cylinder block first, then to the cylinder head, but the new engine adopts a cooling system in which the intake side is cooled first. After the engine coolant cools the intake ports of the cylinder head, it then cools the cylinder block and cylinder head. By using this cooling sequence, the intake air temperature is reduced and knocking resistance and volumetric efficiency are improved .
The shape of the exhaust manifold was changed to match the newly-adopted WU-TWC manifold converter.
In addition to a knock sensor, the 7A-FE had a torque management feature which cut torque while the automatic transmission shifted to minimize harshness.
how much of this is true and really 7afe specific? the thing about the PCM reducing torque between shifts, how does it accomplish this or was this feature never implimented?
That torque cutting sounds similar air shifters used on motorcycles for drag racing. When you hit the shift button, the ignition is killed for a split second and that unloads the transmission to allow for a no-clutch shift accomplished by the compressed air powered shifter mechanism.
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'88 Corolla, AE92 SR-5 (7A-FE swap in progress)
'87 Corolla, AE82 FX-16, 4A-GZE swap (autocrosser)
'03 Tundra 4X4 Access Cab, (FX tow vehicle/Home Depot runner)
Modification: Changing something to what you thought it should have been from the start!
That torque cutting sounds similar air shifters used on motorcycles for drag racing. When you hit the shift button, the ignition is killed for a split second and that unloads the transmission to allow for a no-clutch shift accomplished by the compressed air powered shifter mechanism.
but i'd DEFINATELY see that on my wideband, and i dont see a sudden rich spike.
Compared to the older 4A-F the valves are bigger in the newer head, so it would be correct.
JDM cams are the same as your cams.. doooh. Not everything JDM is about performance.
different emissions rules over there can mean different cam grinds. so does the 7afe have a different grind than the 4afe or did they mean compared to the 4af?
different emissions rules over there can mean different cam grinds.
Not really, different emissions rules are dealt with adding cats etc. Japan is a lot stricter (they have probably the most strict) emissions regulations than pretty much anywhere else.
Probably compared to the first gen 4A-F/FE, they're ground differently. As far as I know the 2nd gen heads are the same.
Not really, different emissions rules are dealt with adding cats etc. Japan is a lot stricter (they have probably the most strict) emissions regulations than pretty much anywhere else.
Probably compared to the first gen 4A-F/FE, they're ground differently. As far as I know the 2nd gen heads are the same.
thanks, so the page is a bit misleading in the 7afe specific section? it makes it seem like those things were ONLY to the 7afe and not the 4afe also.
The newest version of 4A-FE had an intake and head similar to the 7A-FE. At least on the outside, I have mistaken the newer 4A-FE for the 7A-FE in the junkyard, until I looked at the oil pan.
So! Would the 7A-FE, or the newer 4A-FE head and intake fit on the older 4A-FE. That head and intake is supposed to produce better volumetric efficiency, but the article doesn't say if there are real world gains are from that, besides knock resistance. H/P, torque? Anybody have an idea?
__________________
'88 Corolla, AE92 SR-5 (7A-FE swap in progress)
'87 Corolla, AE82 FX-16, 4A-GZE swap (autocrosser)
'03 Tundra 4X4 Access Cab, (FX tow vehicle/Home Depot runner)
Modification: Changing something to what you thought it should have been from the start!
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if it is...i wonder how much the JDM cams go for 
would be easy to do along with my timing belt.
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