1975 TX Coupe "Zero" - Lowdown Styled Drift Gem

elky · Post by **elky** » Sat Nov 17, 2012 8:22 pm

my stock (but healthy) g200w is making 116hp at the wheels, the twin carbs is the key here, after driving the drag gem the ZZ/T is sloooowwww, get it running first as is, you will find the torque thrust is heaps fatter than a sohc, then go quads

there is a mob in brissy doing 45mm quads for $500ish, cant remember the name atm tho

the only issue i would have is oiling on the cams at sustained high revs with g forces.....

cheers

Hachikansai77 · Post by **Hachikansai77** » Sun Nov 18, 2012 2:31 am

elky wrote:my stock (but healthy) g200w is making 116hp at the wheels, the twin carbs is the key here, after driving the drag gem the ZZ/T is sloooowwww, get it running first as is, you will find the torque thrust is heaps fatter than a sohc, then go quads

there is a mob in brissy doing 45mm quads for $500ish, cant remember the name atm tho

the only issue i would have is oiling on the cams at sustained high revs with g forces.....

cheers

Agreed, and honestly your twincam is what I more or less used for a reference of what mine should be capable of.
Twin carbs or ITBs would be awesome, but I guess it depends on how much time and money I have to outlay on doing it, as ultimately I want to build a good strong forged motor with one of my (many) G180Zs, and the huge Garrett + Plenum and other bits, so that I can be reasonably competitive down the track.

Having said that, if you find out the name of that mob, let me know and I'll weigh up my options

F3ARED · Post by **F3ARED** » Mon Nov 19, 2012 5:59 am

BackToTheGem wrote:Those figures would have to be better than a big port 4age. Just for comparison's sake my old man's clubman made 100rwkw on the dyno with a dead stock silver top 20 valve.

This coupe's going to be cool - makes me want to hurry up and get mine finished

Yeah the 4AGE 16V's dont come close. Despite what the Toyota fanbois will tell you, they are only worth 65-70rwkw standard. When Daniel had the ZZ/R on the dyno it made 75rwkw bone standard. Having driven both twin cam geminis and 4AGE powered KE70/AE71 Corollas, i can tell you the 4A comes nowhere near the G series DOHC, especially in torque.

In fact... I wonder if the plenum on the twincam shares the same bolt pattern to the runners as a 4Z series plenum. If so, I could actually swap the top half to the Gemracing (?) plenum and large TB from your old turbo setup that is now sitting in my shed. I'm not using it for anything for ages yet, so might be worth looking into

Doesnt hurt to try it i guess, wouldnt suprise me if they were interchangeable. That said, even just turfing the twin-butterfly throttle works wonders.

redzone (coxy) · Post by **redzone (coxy)** » Mon Nov 19, 2012 12:34 pm

The plenum bolts up vertically on a dohc, the sohc bolts up horizontally so no go on that swap! The hdt gem used quad throttles on a stock bottom half, i'll post a pic of it soon..

Hachikansai77 · Post by **Hachikansai77** » Sat Nov 24, 2012 5:27 pm

Yeah, took a much better look at the plenum style when I finally pulled it into the shed today... no go

Wouldn't surprise me if the lower half could be used, but I think if I was going to go ITBs I'd ditch the lot and start from scratch. Had a quick look on Gumtree the other day and a set of GTR throttles is about $350 locally... tempted to say the least.

Pulled the G180Z out today, and whipped the rocker cover off the W to have a quick look:

Also fished out the Group A headers and gave them a test fit, clears the engine bracket nicely.

Question for anyone who might know; what sensors are these for? (middle bottom, and top female plug jutting out at an angle):

They are the only bits of wiring I can't quite wrap my head around looking at everything. At a guess all I need to really fix up is coil wiring, fuel pump, battery, starter cable and these two.

Comparing the twincam box (MSG 4 with twincam bellhousing that is...) on the left, and the MSE 4 on the right. Obviously I need to re-position the crossmember bracket further "up" the box, and possibly make do without a speedo due to cable clearances.

Left crossmember is the one to use, right one came on the twincam's box, and obviously is unsuitable for this Pre ADR TX.

Other than that though, it should be fine. I test fitted this in a post ADR TX a while back, and while the motor needing plates for the mounts, the gearbox sat perfectly

Ran out of time today, but tomorrow I'm hoping to do a dummy fit and see what measurements I need to take.

*Edit* oh also, I downloaded a skin on Forza for my Hakosuka, which is pretty damn close to what I have in mind for the Coupe:

Hachikansai77 · Post by **Hachikansai77** » Sun Nov 25, 2012 5:43 pm

Looks like it was made to be there... oh wait, it was

Gearbox went on really easily too, and based on it's position, I will still be able to use the speedo cable with no mods whatsoever.

BlueGem · Post by **BlueGem** » Sun Nov 25, 2012 6:22 pm

Hachikansai77 wrote: Question for anyone who might know; what sensors are these for? (middle bottom, and top female plug jutting out at an angle):

They are the only bits of wiring I can't quite wrap my head around looking at everything. At a guess all I need to really fix up is coil wiring, fuel pump, battery, starter cable and these two.

No idea on the melted one because mine was the same! But the other one is the air bypass, there is a connector on the intake pipe that connects to one side then the other side connects to the plenum.

Hachikansai77 · Post by **Hachikansai77** » Sun Nov 25, 2012 8:25 pm

Ahh that makes sense, the hose coming off that at the other end wasn't hooked up to anything I don't think, but that would be because this uses a different style of inlet piping with a pod at the end. I'll have to have a look at it again and grab a pic.

That other melted/broken sender must take a different plug to the others, just because there's only one other plug going to that area, and it doesn't suit anything else. The one on the far left would be the one for the standard temp gauge at a guess?

MR ZZZ · Post by **MR ZZZ** » Sun Nov 25, 2012 9:12 pm

Twin cam looks good! I'll come up for a geez once i'm not so crook!

Hachikansai77 · Post by **Hachikansai77** » Tue Dec 11, 2012 1:09 am

Progress has been made!

Engine: now mounted! I was able to get around using plates (the idea of it really didn't sit that well with me) by instead using a wide SOHC engine bracket on the drivers side, which nearly lined up perfectly with the petrol crossmember. On the passenger side, I couldn't swap brackets because the exhaust would foul on it, so I instead used one of the earlier round engine mounts and moved it forward on the crossmember itself. This coupled with some strategic work with the drill bits and grinder means that it now sits pretty much perfect, however next time I think I'll go with the diesel crossmember, so much easier!

Fuel: I picked up a standard VL EFI pump on the weekend, which suits my setup perfectly. The surge tank outlet is nearly the same size as the pump inlet, so I won't need a reducer after all. My fuel regulator + gauge arrived today as well, so that side of things is pretty much done, just need to mount it all tomorrow or Wednesday.

Exhaust: the group A headers aren't a bolt in job, but it's not a very big deal. I'm in the process of marking out and cutting to size the mid section to attach to my 2 1/4" straight pipe. I'm thinking of putting a flange on the end of the headers, along with further down to make it all easier to remove, since the underbody is one piece. Hopefully getting it all tacked together tomorrow so that I can make sure it fits before the final assembly. Will be getting a wideband O2 bung fitted as well.

Wiring: I've sat the twincam loom in the bay in vaguely the position I want it all, but I still need to run a few wires here and there, and trace a few others that I can't work out. I have a mate coming over on Thursday who is a wizard with both EFI and twincams, so fingers crossed everything will be ready for it fire up by then.

So yeah, gradually getting there

Hachikansai77 · Post by **Hachikansai77** » Mon Dec 17, 2012 11:42 am

Getting so close now!

Antus came over on Thursday and spent the whole afternoon/evening getting everything working properly.
Fuel system is all plumbed up. Fuel pump, regulator, and surge tank are all mounted properly. A slight weep is still coming from the return fitting off the reg back to the tank, even after tightening the bejeezus out of the clamp and the fitting, but maybe still not enough.

The wiring took a while, for some reason the 12v ignition source changed from one wire to another. For the moment I have it spliced together just so I can power things up and test, but eventually the twincam loom will run under the dash and everything will be done properly. Was a good feeling getting power to the ECU and seeing the hand controller light up for the first time

After that, I sourced the starter wires and power to the coil, and the next day after some more fettling tried the key. Got some sparks, but nothing major. After a little more work I found the plugs were black, so changed those out, set fuel pressure to around 2bar and got it firing reasonably consistently, then hit the next wall...

As per this thread: http://www.ozgemini.com/forums/tech/vie ... hp?t=24115 I am having issues with the TPS. After searching, asking around, and testing it I can be fairly sure it's faulty. Unusual, since this whole package was pulled from a running car, but I didn't store it completely undercover for the 2 and a bit years I've had it, so perhaps in that time some moisture got into the sensor and it failed as a result.

It'll be at least another day or two until it arrives, and the private day is on Saturday, so it's not looking too promising

I'll still go, just in the red TE again, but I get a little closer each time, and considering it's only been a couple of weeks since I decided to do this conversion, I haven't done too badly to get this far. Not without Antus' help of course...

Hachikansai77 · Post by **Hachikansai77** » Thu Dec 20, 2012 9:19 pm

So, my new TPS arrived at about noon today, very happy with the service EFI Hardware provided, even if it did cost a bit. I reckon I'll be looking in their direction when I start seriously brainstorming ideas for ITBs on this motor.

Anyway, so I tested resistance across the sensor as soon as I got my hands on it, and got exactly what I was after. By 12:30 I had the wires spliced and it fitted onto the motor exactly as the old one came off.

12:31 - this happens: http://www.youtube.com/watch?v=zZgNVYsz ... e=youtu.be

I honestly was not expecting it to just start up and run like that, but it shows that this package was pretty much ready to go once the fuel system was set up. The throttle return spring is pretty piss poor, so until I fix that and a few other small things I can't really do much more than this.

Also went ahead and finished up the exhaust today. Even with a pretty beefy muffler on the back it sounds tough! Not bad considering I did the measurements bit by bit, the cuts with a grinder, and got it all welded up out of car. Final product ended up being the headers cut back a bit to 2 1/2" Diameter, same width through the downpipe to a flange, which bolted to my 2" straight pipe. Still need to get an O2 bung fitted, but this will do for now.

Unfortunately it's too late to finish it for the private day, so I'll be taking the red Gem again for one last drive before I tear into it for the diesel conversion. Thankfully there's not much left now for the Coupe, so it should get a shakedown within a month or two if I work solidly at it through the holidays.

Hachikansai77 · Post by **Hachikansai77** » Mon Dec 24, 2012 8:09 pm

Had a good day out in the TE, even though it still suffered overheating issues. I'm only more determined to get this one done now!

Getting right back into it the next day, I'm happy with how the motor sits now, so I ran the loom back under the dash, mounted the ECU, relays, and just generally tidied everything up a little.

Before anyone asks, I'll be most likely mounting it on the inside of the dash once the car is completely running. For now I have it where it is so that I have easy access to it for tuning and diagnostics.

I also finally got the engine fan issue sorted out, by spacing it out from the engine pulley with a few extra nuts. However, if this one gives me cooling issues I already have a thermo relay and wiring to suit. Just need to get an adequately sized one.

How I have the passenger side engine mount set up. I took the bracket off today and slotted the hole a little more, to take the strain off it.

Current boot set up, not much but it works. I will be re-running the hoses to make it a bit neater, but this will do for now.

Not bad for $40 off ebay, once you tighten the fittings enough

Old vs New, not hard to see the difference this should make. Weirdly they are an awful lot easier to fit, and are designed to be used with normal G series starter motors which is a big plus. No doubt I'll probably go through a few...

Not a bad way to spend Christmas eve. I've just refitted the rad and put some coolant in it, so I'm going to test for leaks next, then I can move on to potentially putting the rear end back in it and seeing if it moves

redzone (coxy) · Post by **redzone (coxy)** » Mon Dec 24, 2012 9:29 pm

If you're not using those headers I sent you, I have a mate who will buy them off you

MGOTD · Post by **MGOTD** » Mon Dec 24, 2012 10:26 pm

if it's a track only car why bother putting the ecu behind the dash? i would leave it where it is so it is easy to get to to make any adjustments that might need to be made at the track etc