I always wanted a white AE86 hatch touge monster, decked with JDM bumpers, Work Dori Dori's, and A screaming 4A engine. Sporting Cusco Blue galore, and an aggressive stance. But finding clean corolla is getting tough these days. After 25 years many are wrecked, rust rotted, raped, and tattered. So when I saw this 1986 Toyota Corolla SR5 in a unmolested natural form, I HAD to get it.
 |
| Just look at her! |
Yes, it is unfortunately a SR5. If you don't know corollas, it is ultimately the bottom of the barrel of the AE86 Chassis. While the chassis is identical to a GT-S in every way except it's vin, that's almost the only common part of the car. In fact it's almost closer to its sister, the AE85. The 4A-C engine is essentially a 4A 1.6 liter block, however it features lower compression pistons, a weaker 6 bolt crank, and a carbureted reverse-flow SOHC motor. The rear end is also a smaller 8 bolt geared for economy use, with less desirable drum rear brakes.
 |
Here is the original 4AC engine in my car. As
you can see, goodies have been added, but the motor has been untouched
besides basic maintenance |
At this point I have changed some things on my car. But one thing I have left alone so far is the engine, and there fore the stock carburetor. Don't get me wrong, the car ran great when city driving. But as the car started cornering faster, and pushed harder, the stock setup would die out mid corner. Not only is it frustrating to loose power, its devastating to a car with only 70hp. I had a few options here. I considered rebuilding the stock carb. I considered a Weber or twin side draft carbs. I even considered using ITB's from a Silvertop 4A-G and going with fuel injection. What I finally landed on, was a set of Mikuni 39mm carbs off of a 1998 Yamaha R1. That's right, I'm using motorcycle carbs.
Here are the new carburetors mocked up in the engine bay.
I found these for sale for $200 shipped and jumped on the chance to get them. however this swap turned out to be a bit more to swallow then i had thought originally, and things just proceeded to go backwards. First off I had arranged with the seller $200, but come to find out last minute, he meant CA$ and not US$, jumping the price up around $40. Not bad, so I still went ahead with the purchase, only to find a exact same set sell for $140US locally. Alas! My next big mistake was that i went straight ahead and pulled all the stock components out of my car to have it ready when the new carbs came in. I took care labeling and carefully documenting vacuum lines in case I ever wished to return to stock. Unfortunately as I finished this up, I got my tags renewal notice in the mail! Now feeling kinda retarded my goal of making this swap as fast as possible became more important. I purchased a spare intake and exhaust manifold so i could freely modify them and still be able to return to OEM spec.
The exhaust being steel, I was able to modify myself. See the OEM setup has a "Cold Start" box in the exhaust that is designed to draw hot exhaust air into the intake manifold for driveability in cold weather. What a great way to rob power Toyota! Not only does this cause restrictive exhaust flow, it also leaves a giant whole in the manifold when the intake manifold is no bolted in. Problem! Since I needed to basically make a new intake manifold, this needed to be dealt with. What I ended up doing was hacking out the box, and replacing it with a segment of my buddies old stock MX-5 exhaust manifold I had laying around.
With the exhaust done, my attention switched to the intake and carbs. I brought my intake manifold to a local shop in Phoenix called Future Fabrication. They do amazing work, and those are some really cool guys. However, I was not too pleased with this particular experience. I brought him the carbs and manifold and explained what I needed, and what i got was a very simple manifold design for $100. basically the stock flanges and 4 runners coming straight out. Problem was that the runners did not line up with the carbs and made mounting impossible. So I brought the manifold back. At this point i was not upset at all with the guys a FF, but it did need fixing. Now this time they did a bit more work, but with the first one being $100, and the fact that they had 90% of the material already paid for and on the manifold already, I was expecting another $100, maybe $200. The price I was given when she was all said and done however was $350, bringing the total to over $450 for a simple manifold. I bit my tongue as the work was great but also way over priced in my opinion. However when I got back home one thing was painfully clear right away. I had said that the whole setup (carbs and manifold) needed to fit in a space of roughly ten inches, so being compact was crucial. Yet when I fit everything together and measured it out, it came out to exactly ten inches!!!! while everything did fit, it meant that my carbs actually touch my AC lines and cause a racket throughout my engine bay and under my dash. Also as my plans are eventually to go with boost, I now have no room for a Intake Plenum, and I'll need yet another intake mani later down the road.
Needless to say at this point I'm pretty heated. I'm running out of money, time, patience, and I just need my car up and running again. Now with everything put together it's time to tune this thing! Nope.... I was told the 4ac fuel pump works perfectly with these carbs, but I should have known better to trust interwebz. These carbs are designed to run on roughly 3psi of fuel pressure, unfortunately the stock mechanical pump for the 4ac puts out 4psi. Not a big difference right? Wrong, the pressure was enough to cause fuel to spit out of all four float bowls and pour onto my exhaust manifold, which as you can imagine has great potential for a dangerous situation. So I went ahead and purchased a Holley low psi FPR, new needle valves, new o-rings, new jets, fuel line, and new hose "couplers." these bringing my total from around $700 to $1,050. All for a 4A-C... wow. She did however finally hit the road, for a very short time. It became quite clear during a "testing session" (which involved Peoria Police Dept. and will be saved for another story entirely) that the free floating design of the carbs wasn't going to work on my car. So after some homemade carb brackets and some pink paint, she was on the road finally. NOT finished, but back on the road.
Here she is with the carbs still in the development phase. I've since added brackets, and lost the ghetto rigged throttle cable-ness.
Thanks for reading, Check back for Pt. 2!!
