Vertigo's AW11 MR2 Turbo

[Vertigo]

I have two AW11 MR2's - one turned into a mule, and the other is my daily. This thread is about how one turned into the other.

The project started seven years ago, when I bought a silver AW11. It was tidy enough, but had a bad engine that kept overheating. I attended a Toyspeed meet in '11 down in Manfield, and after the journey there, doing a few laps of the track, and the journey back again, and having to put up with blowing coolant everywhere every so often, I had had enough, and arranged to buy a 4AGZE smallport, with the intent to rebuild it over a summer and within a year of that, throw a turbo on it. It would be my first engine build to be completed, though I had practiced a few times with various 4AGE's that never made it to completion.

Summer arrived and departed, and the engine was in pieces. Money and time were the issues, but I kept at it, gradually acquiring parts, planning etc. I realized this would take a lot longer than I figured, so a year later, I swapped the overheating 1st gen bigport out for a 2nd gen bigport, which was a supreme workhorse and lasted the next four years without any problems. Progress continued on the 4AGTE build as time and money allowed, but was interrupted for a few years, and stored at my brothers workshop. At this point it was an assembled short block and reconditioned head with bigport cams.

Financials improved in 2015, and my brother was moving, so I arranged to pick up the engine, and immediately I got the itch again. Within a week or so, the head was torqued down on the block, timing belt set, and turbo slung on the side. It should be noted that the turbo at this point was a T3 flanged China special with a stainless steel manifold that was highly likely to bend. But its what I had. I had some oil and water lines made up, and then started planning the supporting mods.

* Adjustable rising rate FPR
* 440cc 7MGTE injectors
* MTX-L wideband gauge
* Megasquirt
* Celica W2A intercooler, radiator, pumps, and hoses suitable for an MR2
* DPR blowoff valve
* 2.5in twin-outlet exhaust with 20v headers

At first I tried using the dual coil packs and CAS that came it, using a Mitsi dumb ignitor with the Megasquirt. The intent was to get this I didnt have much luck getting it to run, so tried a coil-on-plug setup, with the Megasquirt set up for sequential ignition. This also proved hard to perfect, so while I havent given up on it, I figured the distributor based system that was in the car was good enough for now. And it ran, and I was getting bored with ignition.

The engine itself is mostly stock. It was bored over 0.5mm, acid dipped, crack tested, shot peened, fully balanced, align bored, skimmed, the works. I wanted this thing to be bulletproof. I fitted brand new factory forged pistons and ACL Race Series bearings to the block. The head was reconditioned to factory specs, but with some slightly bigger bigport cams that I had lying around. I fitted some adjustable cam gears, a Cometic MLS head gasket, and ARP head studs and flywheel bolts. Soon enough, there was nothing left to do, so it went in. And fired up. And it was glorious. The engine that I built from scratch was living and breathing.

Its now done about 5000km, and hasnt missed a beat - its been a huge success. Im so happy that nothing has gone wrong with it.. because any kind of engine failure would probably kill the project, and it proves I did everything right. If Im honest, I had reservations that the engine wouldnt destroy itself as it sat there about to be fired up for the first time. But no, its proven to be a perfect runner. Around 8.5:1 compression, 160psi on all cylinders. As I was having issues getting the Megasquirt running well, due to dodgy grounds, mostly, I ran it on the stock ECU for the past couple of years. I attempted to mount the turbo (venting to atmosphere), and had a return bung welded to the sump, but it was too restrictive and resulted in smoke billowing out of the exhaust. Its possible I could have fixed things by just using a much bigger oil drain, but I decided to go down a different route.

A year ago, it failed a WOF for structural rust, and when I went hunting for the worst of it, discovered most of the front firewall was being eaten away. I figured I could sink money into it in an attempt to revive the car, or find a pristine AW11 instead. Well, I found one. It has been completely de-rusted, a top quality paint job applied (dont care about color so much), 205-wide 5-spoke deep dish wheels, wheel arches, adjustable suspension, Bride bucket seats, braided brake lines, and (the finishing touch) a Silvertop 20v with open throttle bodies and a Blacktop ECU. Pretty much everything I wanted in an MR2 that I hadnt already done to the silver car. I snapped it up in a heart beat.

So the project officially is now the yellow car, and the silver car is deregistered, but still in use as my test-bed. It still holds the rebuilt smallport as its heart, for now, but that will be swapped into the yellow car in the near future.

Earlier last year, I found a good turbo setup, previously used on a race spec Corolla. It had a wicked low profile tubular manifold that sat the turbo, a TD05HR, quite high, which is exactly what I was after. Unfortunately, when attempting to fit the thing, I discovered that while it bolted on ok, the inlet to the turbo was blocked by all of the AW11 gearbox linkages, making any attempt to use an air filter impossible. I sold that turbo and manifold for what I bought it for, and considered going back to the original turbo, and sourcing a scavenge pump to solve the smoking, but then as luck would have it, while bitching about this situation on the MR2OC forum, one of the members had the solution - again, a TD05HR, but this time with a manifold designs specifically for AW11 MR2's. The manifold sits the turbo slightly skewed, and so clears everything it needs to, and the inlet is freely accessible. Bought it immediately. Test fit, no problems. Went ahead and started planning a foolproof oil drain for this unit.

Took the sump off and drilled out a hole for a large brass fitting, sealed on both sides, and had the turbo outlet bung modified with a -12AN full flow bung, and a matching AN-to-hose barb fitting. Initially I wanted to see what the oil was doing, so am using a length of transparent hose entirely unsuitable for the application, but its serving its purpose. Itll be replaced with something more suitable for heat and oil very soon. Also had exhaust downpipe and turbo uppipe sections made, and finalized the rest of the intake charge piping, intercooler hoses, wiring, etcetc. Just recently, I managed to fix the remaining issues the Megasquirt was having, and got it running well, so there wasnt much left holding me back from going for the first run with the turbo. No smoke! Despite having a guesstimate tune (rich and retarded), and an exhaust leak at the manifold, it boosted for the first time up to 5psi. Great power delivery, though a little late in the game - guessing its due to the aforementioned exhaust leak, and possibly boost leaks. Also probably the tune. Everything can be improved upon from here.

So thats where the project is at for the time being. More to come. The ultimate goal is 15psi and near-enough 200kw.

[Vertigo]

Rather than clutter the internet, Im consolidating my build threads to a single forum on mr2.org.nz.

Would you like to know more?