4AFE TO 20V 4AGE A/T ENGINE SWAP
4AFE Specs: Hp 103@6000, Torque 102@3200, Bore & Stroke 3.19 x 3.10, Compression 9.5, MAP
The 4AFE is a torquey, reliable, and somewhat efficient engine. A modified 4AFE and light weight AE92 is a spunky combination, but the engine hits a performance barrier that will prevent you from being competitive with similar displacement equally modified cars. This is due to the narrow valves, the slave cam system, the low max RPM, and the DX's 3 speed trans. One cam sprocket is driven by the belt, and the other is coupled to it by a scissors gear. You have to modify the exhaust cam sprocket if you want to adjust the timing. The valve angle on the F series is narrower than the G series engines. See image My goal with this engine swap was to have a practical, well balanced, fun-to-drive, street performance car. Well I had each of things but I wanted more. With the mods I had I was getting decent mpg, but it was time to get rid of the 3 speed trans, and the whole F series head was starting to get on my nerves. My 4AFE had + 220k miles on it and had not been taken care of by the previous owners. Econo Lube N Tune also did me the favor of putting a fish tank filter in the air box back when I didn't know anything. Say bye bye to my piston rings. Not only do they rob you, but they give you a good fuck up your ass for good measure. Months later my air box was full of sand and the throttle body was clogged with grease. Never, ever take your car to a corporate name-brand shop. Always try your luck with a local foreign-car-only shop named after the owner.
Opening up the exhaust on this engine will unlock a respectable amount of power. First get a Pacesetter header (70-1153). It's poor quality, a 4-1 which sets your power band too high, but the price is right. The black paint will burn off and the header will start to rust in about 3 years. You can replace it with some high temp paint. Don't waste your money on the ceramic header. You can try the HP racing header for the 93-97 Corolla 4AFE, but you will need a screw type O2 sensor. The AE92 sedan has a flange type O2 sensor, so just have the parts store look up an O2 sensor for a 1.6L 93 Corolla. Don't get Bosch. With the pacesetter you will have to file down the weld in the O2 sensor bung. If you do not use your O2 sensor, your ECU will go into limp mode seriously hurting your car's performance. Tack weld the heat shield and you can get past the visual smog check in CA.
After you have the header, get a custom 2 inch diameter cat back exhaust at your local performance muffler shop. There are some catalogs that sell mandrel bends if you want to go that route, but performance wise, it's not worth the money. Neither is the pacesetter cat back which is available for the coupe. The exhaust makes two 90 degree bends, and then loops up over the control arms. Here I have an acrobat file full of stock Toyota exhaust systems. If your cat is clogged up, now is a good time to get a generic weld-on high-flow cat. Bolt-on is ideal. Get a Cherry Bomb glasspack and have it mounted reverse of how it is intended. That way it wont affect your performance but will deepen the tone. Magnaflow makes a very high quality, low priced muffler. DO NOT GET A FLOWMASTER!!! Skip the exhaust tip. It just aint happening. I did all these upgrades at seperate times, but I paid $150 for the muffler and pipe installed, $30 to add the Cherry Bomb that I got for free, $110 for the header, and $70 for the Catco.
There's no good reason to remove or especially gut your catalytic converter. Gutting your cat will hurt your performance unless it was clogged. You now have an open chamber causing turbulence. A high flow cat has less back pressure than any performance muffler, or even a bend in your exhaust pipe. Some racing leagues don't run cat converters, but this is because they tune even the sound resonance of the entire exhaust, something you and most aftermarket exhaust companies are not capable of and are unwilling to spare the expensive for such a small horsepower gain. I should also point out that a cat-less exhaust sounds like total crap and even Honda people will laugh at you. If you have an oil catch can on your PCV, make sure to vent the air back into the system somewhere before the cat. Not directly into the atmosphere! Yes, the environment is a concern. Would you shit the bed you sleep in? No? Then why fuck up the air we all (your and my kids) breathe? It is possible for a well-tuned engine with aftermarket ECU to pollute less than a cigarette.
The aftermarket intakes available for the 93-97 4AFE Corolla will fit the AE92 sedan, but you're even better off making your own. The cheapest an easiest DIY intake is just a K&N cone filter at the end of your flex pipe, with a heat shield protecting it. This setup provided the quickest throttle response and actually gave me more power than the 2 inch diameter pipe, filter-in-the-bumper setup I tried. Later I switched to 3 inch diameter.
You have two options for routing a cold-air intake. For both I recommend moving the battery to the trunk as explained in the CHASSIS section. If visual smog checks aren't a problem for you, cut down the rubber from the flex part of your throttle body just enough to accept the pipe and contain your IAT sensor. Not-using your IAT sensor will hurt your car's performance at the very least. If smog is a problem, you can at least remove the three air chambers on the flex pipe and plug them. I'm pretty sure they're just to quiet the intake sound. Remove all of the intake chambers in the engine bay and inside the fender. You will need a new place to mount your diagnosis plug. Keep all your stock parts and put them back on for smog checks. Go to www.4AGZE.com and www.ae92gts.com for other options.
My method requires some kind of 2.75 - 3 inch diameter straight pipe with a 120 degree bend at the end. 2.75 inch will fit nicely into your flex pipe and after some minor cutting there is 3 inches max of clearance between the unibody and headlight bracket into the bumper. I think the length of the pipe without the bend is 1 ft 9.5 inches. Preferably it should be thin, non-corrosive metal wrapped in heat tape, but even plastic that is somewhat heat resistant will work. Wrap the heat tape longways. Don't try to wrap it like a candy cane or you'll crinkle the living fuck out of it. A quick safari through Home Depot will turn up material for making a heat shield. You want something that doesn't conduct heat well.
The cutting involves some sheet metal snips and a pry. Remove the headlight and bracket but don't touch any of the headlight adjustment screws. Cut the useless sheet metal that extends from the unibody behind the headlight. Then seperate the headlight from the bracket and pry off the piece that redundantly secures the turn corner lens. Cut off the lower corner, fitting it back to the car and jamming your pipe against it as a reference as to where to cut. Shove your intake pipe into the throttle body flex pipe and secure it with a clamp. At the other end of the pipe, you have a 120 degree bend fit between the cut-out unibody and headlight bracket. That bend is then shoved into an oval shaped K&N filter, which hangs down into your bumper. It is a good idea to secure the pipe and filter with mounts or clamps to your car, although I haven't had much trouble with it rattling or moving around. Put your headlight and everything else back on and then unplug your battery for a few minutes to reset the ECU.
You can cut out sections of your bumper for ram air and put some kind of tight gapped grill that will limit the amount of and pressure of water that splashes on it. It's a good idea to vent air into the bumper around but not directly on the filter. This will raise the air pressure and it will be practical for street applications. Otherwise grease quickly builds up on the filter. Water splashing directly on the filter at a high speed will go right through it. It is unlikely that any water will make it into your combustion chamber, but if enough water vapor does complete this happy little journey you can kiss the engine goodbye. If you completely submerge the filter or if the filter becomes almost totally restricted, your car will stall. I have never had any problems in wet weather or driving through small puddles, but I advise that you use common sense and consider moving your filter up into the engine bay (as per my first intake suggestion) temporarily during wet weather. It's easy to fit the filter directly to the flex pipe on the throttle body using a short piece of pipe and a clamp.
The 4AGZE is the fastest, easiest to get more power from, and the best choice if you want forced induction. You can reach 200 hp with just a pulley and a front mounted intercooler. For that much power a 20V would need a turbo and some serious internal modification. The GZE is a factory supercharged engine and so it has strong internals. The US version from the MR2 came with a compression ratio of 8.0, AFM, and ran a distributor for 145hp. In Japan they were available in a number of cars, had a compression ratio of 8.9, MAP sensored, and ran DLI for 165hp. Converting to the US version GZE makes it possible for your swap to be smog legal in CA. It also means that getting parts from the junkyard or Toyota dealer will not be a problem. Alan Zee's 4AGZE sedan truly hauls ass. Go here and click on AE92 S/C Sedan.
20 valve 4AGE
There are two versions of the 20 valve 4AGE. One ran from 1992-96 and the other from 1996+. The earlier silvertop version came in the AE101 and uses an AFM sensor, while the second blacktop engine uses a MAP sensor and is associated with the AE111, although there was some overlap with the AE101 in 1996. These engines are both distributed ignition, iron block like all other 4AGEs, have 3 intake valves per cylinder, 4 throttle bodies, and rev to 7800~8200. They use Toyota's VVT system which stands for variable valve timing.
VVT is essentially an ajustable intake cam pulley with a switch on it. When powered on (switch to ground inside the ECU), it advances the timing 15 degrees giving you better low end. When off, it reverts back to normal cam timing so as not to hinder top end power. It is switched on around 4400 RPM and off again around 6400 RPM, depending on a number of parameters including coolant temp, TPS, and load. It is the same between both 20V engines although the parameters for controlling it may be different with the blacktop ECU. The blacktop version was altered to make it less likely to leak oil, but the two versions are interchangeable. Do not confuse it with VVT-i. The amount of timing advance does not vary, it's either 0 or 15 degrees. VVT does not increase the amount of air getting into the engine, only the timing it goes in. It's about 20hp inferior to the VTEC on Honda's B series in part because the intention was to increase power in the low end for a predictable flat power curve. VTEC controls timing, increases duration and lift on both the intake and exhaust and is intended to maximize power all around. Toyota didn't catch up to VTEC until the release of VVTL-i on the newest engines. For a much more detailed comparison of VVT to VTEC and a mechanical explanation of how VVT works, seek Bill Sherwood.
BLACKTOP (MAP) VS SILVERTOP (AFM)
The advantages of the "Blacktop" over the "Silvertop" (designated by the color of the valve covers) are: about 5 hp ("ST - 143hp BT - 148hp Both measured at the flywheel on an accurate engine dyno, not on a chassis dyno." Bill Sherwood), higher compression, lightened internals, lightened flywheel, longer intake cam duration, and most notably a MAP Sensor vs. the Silvertop's AFM. Flap door type Air Flow Meters are inaccurate, restrictive, are damaged by oil, and complicate fabricating a cold air induction system. Some Blacktops came with a 6 speed manual and/or limited slip differential.
The Blacktop is much less common to find used than it's Silvertop predecessor, and so it's much more expensive. The blacktop auto trans is not a direct bolt on to the AE92. The front mount is a perfect fit, but the other 2 trans mounts require some heavy modification. The left side AE92 side mount needs to be shaved down to clear the timing belt cover on either of the 20Vs, but if you get the 20V mount this may not be a problem. The blacktop auto trans may bolt directly into the 93+ US Corollas as those cars have different mounts. Wiring diagrams are difficult to come by, particularly for the automatic. Finding some of the typical maintenance parts can be a problem for either 20V, not to mention finding replacement major engine components and engine specific sensors which differ even between the two 20Vs.
For these reasons I've decided on getting a Silvertop, but using AEM's new EMS rather than the stock ECU. The silvertop is available for roughly $450 and the AEM Honda OBD2 costs ~$1300. Compare that price to the price of an entire front cut. Using the AEM EMS I can convert the silvertop to MAP, eliminate the distributor and run DLI, and use any type of sensors I want. This reduces the problem of finding specific sensors should they need replacing, for an engine that was never brought to this country. The AEM lets you choose your own shift points for electronically controlled, automatic transmissions. Another alternative is to get a silvertop engine but a blacktop ECU, harness, and convert to MAP, the major problem being the difficulty in getting a good vacuum reading from the individual throttle bodies.
Thanks Ben Wilson, for the factory engine manual. Thanks Jason Purcell.