I've been driving a Wira Aeroback 1.5 auto, and I changed it to manual earlier this year. Here's what I know -
1) No need to change radiator. In fact, the full-length radiator that comes with auto cars is better than the half-length radiator that comes with the 4G15 manual!
2) Swap out the gearbox - you'll require the flywheel and clutch too. For low cost, use the Wira 1.5's 7.5 inch flywheel and clutch. They're very cheap. In my case, I used a Super Touring flywheel (120 bucks) and used an Exedy 8-inch clutch + pressure plate. Some people say that this flywheel is heavier and the acceleration will be poorer than a stock setup's, but truthfully it's not THAT much an impact. Instead, the car can maintain high speeds much better due to the larger flywheel.. it feels more stable, without that much of a speed reduction when your foot is off the pedal.
In my case, I'm using a 1.3 gearbox because I got it for only RM200.
3) Depending on whether you use clutch cable or clutch pump setup, get the appropriate pedal cluster. This can be obtained for maybe around RM80 at kedai potong. Not very pricey.
4) Get a gear shift + shifter base + shifter cables. It will cost arond RM100.
5) If you're using clutch cable, just get a new cable for around RM60 or so. If you're using a clutch pump, a new clutch pump would be about RM100 or more, but a halfcut one will do.. it would cost something like RM50 only.
In any case, the firewall will have to be drilled for the clutch pump lever or the clutch cable.
The shifter cables will run through the existing auto geabox's shifter cable firewall exit. There's no change to the brake and accelerator cable positions.
For a clutch cable setup, workshops will resort to different ways to get the cable affixed to the firewall. Some of them will just cut a 3/4-inch tube around 2.5 inches long, and weld it onto the firewall. Others will use a combination of bolts and washers and whatever. In my case, the mechanic did a bad job and so I re-did the thing myself with plumbing supplies (chromed joints + washers and bolts on either ends + metal epoxy) and the outcome is pretty good.
A clutch pump setup will definitely be neater.
6) For the ECU connection, you have two options:
i) Send it to a good wireman who can splice your existing cables to permanently fix the auto gear selector to "N" (so that you can start you car and drive around), but with a relayed or switched connection for the reverse wire (the existing reverse connection has to go to the manual gearbox's reverse gear contacts, and have to disengage from Neutral when reverse is closed-circuit). In the end, the auto geabox's electronic controller (that round thing that sits on top of the auto tranny's shifter) must go. If you don't do anything about it, two things will happen - your reverse lights and sensor won't turn on; and if you hit the controller hard while closing the bonnet, a fuse will blow and your central locks won't work. I know, it's weird but annoying.
ii) Get a manual ECU and the wiring. Replace your ECU and wiring with the manual version. This method will take lots of time, but it takes away the guess work. For a usual Wira wiring, the overall wiring loom can be divided into three major portions. You just need to change one portion - the one that goes past the firewall. If I'm not mistaken, it's the same bunch that has the injector sockets, airflow sensor, etc. A good wireman would be able to replace only the necessary parts and splice your existing wirings to the updated ones only where necessary. So far, I haven't encountered any wireman who could do this although it is definitely possible. Usually they're lazy and just want to use the whole bunch in its entirety.
So, there you have it, my detailed account of an auto-to-manual conversion!
