4AGE head on 7AFE, What is all needed? Options

[onnaj]

Hello,

I'm considering (in the future) to put a 4AGE head on my 7AFE block and create a 7AGE.

But I'm wondering what i'm needing to make this work. I searched on Club4ag.com but can't find the right answer.

I don't look for mass hp increase but i hope i can get somewhere near 130-140 hp and even a bit better torque

This is what i know i should use:
1) the 4age head
2) 4age inlet manifold
3) 4age exhaust manifold
4) Porsche 914 timing belt
5) 7afe head gasket (maybe a TRD one?)
6) ....

Can i stay with my standard exhaust system or does it has to change?

And most important for me: Can i stay with the standard 7afe ECU so no new wiring has to be done?

Thanks!!

[PaukST]

Hello,

I'm considering (in the future) to put a 4AGE head on my 7AFE block and create a 7AGE.

But I'm wondering what i'm needing to make this work. I searched on Club4ag.com but can't find the right answer.

I don't look for mass hp increase but i hope i can get somewhere near 130-140 hp and even a bit better torque

This is what i know i should use:
1) the 4age head
2) 4age inlet manifold
3) 4age exhaust manifold
4) Porsche 914 timing belt
5) 7afe head gasket (maybe a TRD one?)
6) ....

Can i stay with my standard exhaust system or does it has to change?

And most important for me: Can i stay with the standard 7afe ECU so no new wiring has to be done?

Thanks!!

I've kicked the idea around quite a bit myself, and while at the moment I'm planning to do a 3sgte swap a good while down the road, I'm heavily drawn to the "special snowflake" appeal of doing something a little further from the beaten track... (My best friend is always ribbing me about how my plans for this car change roughly every 5 minutes )

Take all of what I say with a pretty big grain of salt, because
1) I'm still pretty new at this (even though I did rebuild my 7afe, 1666 miles and going strong!)
2) I have never personally owned a 4age engine (that's a big one)
3) Having never owned a 4age, all of my data comes from The Internet (internet-sized grain of salt )

But disclaimers aside, here goes. This is everything I've dug up so far (at least all of it that's relevant to your questions).
If you take a look at the 4age engine, the distributor mounts up in basically the same spot on the head that the alternator mounts up on the 7afe...


I assume (without personally posessing a 4age) that you can't have both without modification. I figure using the default 4age alternator location is out, since the power steering on the 7afe takes up just about that whole side of the engine, as far as drive belts are concerned. So looking for a solution to this, I came across this thread over here on Club4AG... They were adding an SC12 supercharger to an AE86 Corolla, and needed to move the alternator to the driver side (RWD). They used an AW11 MR2 4agze alternator mount bracket. Again, not sure if it's even necessary, but it's hard to find documentation of 7afe-to-7age conversions... Most builds I find on various forums are 4age-to-7age.

Moving on to compression, people repeatedly claim that the combustion chamber size (in the head) of the 4age is A LOT bigger than the 7afe. I found some info on the 4age piston and head cc's HERE. Some more info on 7afe piston dish cc HERE. I used the information in those threads and wikipedia on THIS compression calculator, along with some common knowledge (which I hope to God is right, or I'm going back to the drawing board all over again ) to come up with the 7afe's combustion chamber volume. According to everything I've gleaned so far, 7afe head is 33cc, and 4age head is 36cc, 7afe pistons are -12cc (a dish), 7afe head gasket is 0.7mm compressed, 4age headgasket is 1.2mm compressed. So, using that calculator, changing ONLY the combustion chamber volume from the 7a's 33cc to the 4a's 36cc, your CR would drop from 9.5:1 to about 9.0:1. Unfortunately, I was completely unable to find any info on whether the wristpin sits at a different distance from the top of the piston on the 7a versus the 4a... you know, in case you were considering using 4age pistons. Again, DISCLAIMER! I got all this from the internet! Also, It's worth noting that I am unaware of exactly what you can do before you end up with an interference engine. IIRC, the 4age is natively non-interference (as is the 7a), but it's worth thinking about.

And about the ECU, I really have no clue about wiring it to make it work with the 7afe ECU. I'm in the dark on this one as well. Also, depending on which 4age head you use, I don't know how you'd handle the T-VIS (bigport heads), or VVT (either of the 20-valve heads).



Remember, I'm no expert! It's pretty likely that I, or any of the many people whose data I used, got something wrong somewhere!