Refloto esto, no se si alguien vio este tema por internet, hai que traducirlo, pero si alguien sabe ingles.....
7A-FE Head swap
The head swap is a relatively simple way to increase horsepower in 6th generation ST's with the 7A-FE engine. To put this project simply: you are taking the stock car removing the FE head and replacing it with a supercharged -GZE or -GE heads (more performance-oriented heads). As the 7A-FE is basically an OEM version of a stoked 4A-GE the block is almost identical to that of a 4A. The supercharged heads are fairly cheap and can be found in the US in the 89 and newer supercharged MR-2s. The NA heads are found in the Corolla GT-S and elsewhere. The GE head shouldn't give you an increase that would really benefit the cost IMHO. This is an option for someone making an all-motor engine, something outside the scope of this topic, so I will focus for the most part on the supercharged (-GZE) head.
The way I figure it- a very conservative figure for power should be at bare minimum a 30HP increase over the stock 7A-FE. (looking at the difference between a stock 4A-FE at 105HP and the 4A-GZE at 135HP in 1989). If you do this swap right you should see far more power available. You already have 0.2 additional liters of displacement in the 7A block that should increase both HP and Torque. The Supercharger pulley upgrade for the supercharger were quite common back in the day and may still be available for less than $100US from either HKS or Toms. Also, if you opt for a programmable aftermarket ECU you have the opportunity to create a far more aggressive fuel curve for the hybrid than the stock 4AGZE ECU will allow. Finally, more modern versions of the 4AGZE released overseas come stock with 180HP (without VVT). This is probably attributable to a more modern head and/or intake design...so a port and polish by a respectable tuner may do wonders for power. Please note however that these heads are more current designs may not be easy to swap onto the 7A block.
What you will need:
Block: 7A-FE stock is fine for a simple swap...but you may want to blueprint and/or build up the bottom end for better reliability (or if you are planning on crazy boost.)
Head/ Intake Manifold/Supercharger/Exhaust manifold from the 4AGE/GZE. You may consider a port and polish while the head is off. Donor car would be an 86(?)-89 MR-2sc for the 4A-GZE. This will also swap the car from a MAP to an AFM. . There are many different revisions on the 4A-GE heads and one revision on the 7A block. You may wish to research the type of 4A head you wish to swap as heads were developed: with and with out TVIS, 16 valves, 20 valves and supercharged. In order of difficulty the swap will be 16V as the simplest, 20 valve, then supercharged (-GZE).
GE Head decisions:
If you want torque go with a RED TOP.
Horsepower, then go will the BLUE TOP.
You may also you the 20v BLACK or SILVER TOP, though this create more difficulty in the conversion.
Timing belt: Because you are switching to a true twin cam design (GE head) it is necessary to move to a new size. A timing belt for a Porsche 924/944 appears to fit this swap.
Cam pulley: Again, becasue you are moving to a GE head you need the cam pulley from the 4A head.
4A head gasket: minor modification may be needed. M
Pistons: forged pistons from the 4AGZE or go custom (you may be able to find 4A-GE pistons).
Rods: 7AFE or custom (for better reliability or if you are planning on crazy boost.)
Fuel pump: upgrade needed (4AGZE or supra pump possibly?)
Fuel injector/lines: 4AGZE
ECU and wiring: 4AGZE should work if you are planning on staying close to stock boost and are on a budget...otherwise look into a programmable ecu. The 7A ecu wont function properly with boost conditions in the manifold.
GZE oil sump pan w/ oil cooler
(optional) Intercooler from 4A-GZE
Basically combine the parts together (easy as that huh?), replace the hybrid back into the car workout the wiring and fuel lines and you are ready to go.
From the Guestbook:
There are some mis-givings in the write-up about putting a
4ag head onto a 7af. The 20V head is much more complicated and currently there is debate as to whether everything does line up properly. That is not the biggest issue though as the wiring is incredibly intense and little
information exists on it. As for Blue Hat and Red Hat
difference, w/in the head itself none exists. It was
a difference in blocks actually that happened in 87+ for
the MR2's. Hope this helps some people
-Hardrvin
Now my words of warning/common sense....
First of let me point out that I have NOT done this swap at this time...so take all information there in at face value and know that I can't answer detailed questions about the swap. All the information I gathered at one point or another online from various sources (and unfortunately did not keep most names/email/identities) so it may or may not be correct and may be slightly different for different generations/builds of the engine. Basically I'm asking you to use this page only as a starting point for the swap...not as your authority. If you want more information there are links at the end to more sources that will give you a more through explanation. Of course I welcome a write up on this swap and would be happy to replace modify this page if someone would care to share this information in a more detailed, accurate form.
Please also note that if you are not doing this yourself...that a lot of work/parts are custom, the block needs to be pulled from the car despite that it ultimately returns, and the use of parts such as drive shafts and tranny that aren't built to handle much power over 115 HP may cause prices to approach, or even surpass, the cost of other options such as:
Swapping in a stock engine comes with a better output than the end result of this hybrid. I'm thinking, of course, of the 3S-GTE with 180-260 HP with no aftermarket upgrades. Remember that the chassis/frame of the Celica was designed to accommodate the 3S-GTE in the GT-4 overseas. Supposedly this is also fairly straightforward, as the 3S-GTE will bolt into 5S-FE engine mounts... which have holes already drilled.
Aftermarket turbo kits ARE available for the 7A-FE. Toyota Australia released about 100 factory built 7A-FTE in the Corolla Sportivo. This was supposedly loosely based on a kit from Tom's (Japan). It may be as simple as finding the right importer...or a Toyota nut overseas to ship you the appropriate parts.
Custom kits/manifolds, etc are available through many places...one that I have heard good things about is Thomas Knight Turbo (aka Knight Turbo).
Basically, I'm saying that this is a project to do at your own risk (financially, safety-wise or otherwise)...and think long and hard about it before you proceed.
For more information I recommend that you visit/email/read the following (where most of this info is obtained from):
