4AGZE -
145hp - 165hp
The earliest 4AGZE has 145hp, and there's basically three ways to get more power from them - by either simply fitting a later version that already makes 165hp, or by fitting the engine with the bigger crank pulley (that spins the supercharger faster, thus making more boost at less revs) from someone such as HKS or Cusco. The third way is to 'hot up' the engine, in much the same way as you would with a naturally aspirated engine, ie, bigger cams, ports, etc. The thing to remember is that you are limited in revs by the maximum speed of the supercharger, which really doesn't like being spun at more than about 10,000rpm. The reason for this is the tips speed of the rotors gets too high, and they will start to melt the teflon seals.
So, you're limited to about 8,000rpm engine speed (the supercharger is run at 1.25 times the engine speed standard, and even faster with the NEVO, HKS, etc, pulleys) which means that whatever you do it must make the engine flow more air at stock sort of revs.
This means that to get another 20hp or so from a 145hp 4AGE then a good clean-up of the inlet manifold & head, and perhaps some larger cams (256°) should easily give you that 20hp that you want. A larger intercooler and far more efficient air ducting (it could hardly be worse in the factory installation!) in & out will also help a lot.
165hp - 185hp
Again, the easiest way to get 185hp from a 165hp 4AGZE engine is to simply fit it with the bigger pulley, and maybe some minor mods to clean up any inlet and exhaust restrictions. Towards the high end of this power scale, I believe that the inlet manifold is a big restriction, as the supercharger dumps its air into a single point in the inlet manifold, which then divides the air up into four runner, one into each cylinder. The problem is that three out of the four runners enter the head at angles far from straight, and so the sharp angle at the junction will cause unwanted turbulence. (FWIW, the #1 cylinder's runner comes in at a ridiculous angle) So, I'd say that if the time and effort was spent on making a decent inlet manifold (or perhaps just fitting a RWD AE-86 type manifold, perhaps) then the vast majority of that extra 20hp would come quite freely.
Larger cams, as in the 264°'s mentioned before will help a lot, but also as with the 4AGE anything much more than that and the factory computer will have trouble sensing inlet vacuum. You can of course run an aftermarket computer that uses throttle position rather than using the MAP sensor, but the success rate of aftermarket computers with 4AGZE's is not great - Persistence will win the day, but I would strongly suggest that whatever computer you look at getting has at least these features - throttle/MAP blending, an external on/off output which is controlled by MAP and/or throttle position, and oxygen sensor closed loop feedback.
185hp +
The best 4AGZE I've ever heard of is supposed to make up around 200hp, and I believe that the chap in question has done all of the above mods to get that much. I think that a good way to help the power output would be to fit the engine with a 1GGZE supercharger, which is about 17% larger in volume and so can be spun slower to pump the same amount of air at the same revs - This means that the engine will suffer a little less power loss that what it otherwise would with the smaller supercharger. This power loss that I'm talking about is the power that the engine needs to spin the supercharger over at high revs. It increases rapidly as the revs build up, and so anything you can do to decrease that loss will help a lot.
This is the problem with supercharged engines - They suffer from rapidly decreasing increments in improvement due to the cost of spinning that blower over ...
So, the trick it to set a target revs in your mind, say 7,000rpm, and make the engine pass as much air as possible around that revs. Again, all the same tricks as mentioned in the above paragraphs is the way to go.
- 2002 Toyota Caldina GT-Four N-spec
- 2004 Toyota MR2 SMT PGP
- 2006 Toyota Rav4
2007 Suzuki Grand Viagra 2.0TD
