and this winds up the discussion for 7ag arguement. 7ag is not enough durable for keeps sake, you have yr fun and sell it:)
taken from Bill sheerwood's article on 7ag
7AGTE 20 valve
The next engine I'm going to build for the Starlet is a 1.8 litre 7AGTE 20 valve one. That's a 7AFE bottom end, a 20 valve 4AGE head, and a 1998 Subaru WRX turbo. This engine is just for fun, and although I do not favour the 20v head for naturally aspirated engines I think they're a very good thing for forced induction as the variable inlet cam timing should let the turbo spool-up faster at low revs than what it otherwise would. They also have more valve area than the 16v does standard, so that allows for more air to be pushed into the chamber by the turbo. I have a set of stock 4AGZE 8:1 compression pistons for it, but otherwise the bottom end will be fairly standard. I only plan to run about 7,000rpm, so the not-so-strong 7AFE rods should hold together well enough.
I have some sneaky plans for the intercooler (A water-to-air, but not conventional) and the way the turbo is mounted.
In the interests of keeping the rest of the mechanicals together, I have bought a bell housing that lets a 4A or 7A block bolt up to the very strong W series Toyota gearbox, and I also have a W-57 sitting at home waiting for it. I'm expecting up around 300 ft-lbs of torque and about 350hp from the engine, so there is no way a typical T-50 would take that and live. Same goes for the diff, I am currently hunting for a narrow Hilux 7.5" diff to put under the back of the car as they're very hard to break.
This engine is a low-budget one, and it's really just for a bit of fun. So it won't stay in the car, but will be sold at some point after it's been run for a while.
