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zep's Gemini Coupe


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DISCUSSION: viewtopic.php?f=18&t=3110

Alright, I've flagged my old thread as the car is totally different now. Here is a mild run-down on what the deal is now.


Isuzu G161z

G200z crank

Bored to 86mm

= 1905cc

O-Ringed Block

Arias SR20DET forged pistons (Gemracing)

Shotpeened G161z rods (Gemracing)

Fully balanced bottom end

Ported and polished G161z head

Oversized intake and exhaust valves

3 angle valve grind

Custom turbo cam

Double valve springs

Head shaved to reduce combustion chamber size

8.0:1 compression

To add: 13 row oil cooler

Intake & Exhaust

4ZE1 injection manifold and plenum

XF Falcon throttle body forwards mounted

High mount tuned length exhaust manifold (BurntRubber)

Mitsubishi Evo 1 510cc injectors

Garrett ball bearing T3 turbo (R33 Skyline)

Custom down pipe (Burnt Rubber)

Mitsubishi E38 VR-4 Intercooler

2.5" exhaust from turbo back

XF Falcon idle control valve

Ignition & ECU


G-EFI 12-1 toothed wheel CAS

Holden Commodore VR sensor pickup

Subaru Legacy coil pack

Link ignition module

Running a wasted spark setup

Fuel System

Custom 1.5 litre surge tank

Bosch 300hp external fuel pump

Carter external lift pump

Sard rising-rate fuel regulator

Standard 4ZE1 fuel rail

Gearbox & Driveline

Gemini 5 speed gearbox

Lightened G161z flywheel

Exedy heavy duty clutch

Custom 2 piece driveshaft

Toyota Hilux differential with restudded axles

4.44 LSD

Custom ladder bar type setup (BurntRubber)

To add: Remote/Short throw shift kit


Billet springs at all 4 corners

450lb front springs

250lb rear springs

New polyurathane bushings all round

Whiteline front swaybar 24mm (non-adjustable)

Tokico front gas shocks

Munroe rear gas shocks

*Shocks are soon to be replaced with adjustables


Hopper Stoppers 1" master cyclinder

Wilwood brake bias valve


VT Commodore 298mm rotors, 4 stud

VT Commodore 2-pot calipers


EA Falcon 297mm rotors

EA Falcon calipers

Wheels & Tyres

Konig Rewinds, Gunmetal, 15x7" ET+40

Goodyear Eagle F1 GS-D3 195/50/15


Original Canery Yellow paint

Yellow primer

Surface rust!

Mirrors removed

Australian TD grille, black

Round headlights

Round headlight surrounds, black

Directional speed arrows!


Knox Auto Carpets black plush pile carpet

Rear seat removed

Racepro fixed-back Arrow 1 driver seat (grey/black)

Racepro fixed-back Arrow 2 passenger seat (yellow/black)

6 point 1/2 cage w/ side intrusion bars

Autogauge 3 1/4" tachometer

Autogauge 2" boost gauge

Autogauge 2" oil pressure gauge

Autogauge 2" water temperature gauge

(all mounted in gearbox console)

Custom blue door cards

And a few pics that show nothing at all:




I'm going to try take some new photos this weekend. Will update again after that is done.


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  • 2 years later...

Ok, I haven't updated this in ages, but I wanted to get the greater OS opinion.

As some of you know from previous threads of mine, I'm looking to put some bolt on flares on the Gem, most probably painted black.

I've looked and looked and looked for decent flares and it's next to impossible to find any, so I think I'm going to end up with ZG flares, or perhaps BAMF Superwide ZG flares.

Regular: http://classicdatsun.com/new/ZG-flares_inst.html

BAMF: http://www.zforceproductions.com/index. ... &Itemid=60

Which would you use? Obviously the BAMF ones allow for wider wheels or a deeper offset but the rears appear to not come down as far at the tips. Now, the reason these look so good (I reckon) on the Z is that the tips line up with the bumpers which are rather elongated, and the upper sill/line running between the arches. My car has neither bumpers that will reach in that far, nor this line, meaning that they will just stop at a point on the arch without real aesthetic reason. What I would really like to do is have the flares custom made so they come right down to the bottom of the arch, but I can't see that happening, far too expensive and I wouldn't know where to start.

So yes, the question is really: Do you think this will look good, and if so, which flares should I go for, ZG or superwide ZG? (Or others if you can suggest)


Flares mean new wheels.

Now I think this looks staunch as fuck with the dark wheels and the poke. Perhaps because the flares are body coloured they don't look as wack while not following the lines. I would love to replicate this look.



Now the wheel choice. 1. Konig Bbombs in 15x7.5 0 offset, opel colour. 2. Diamond Racing steelies in what 15x7/8/9 with the triangle cutouts, black an perhaps coloured centres.





(except obviously not a Civic or in those colours).

What you cats think? I need to start trying to make a decision. Am sick of no dish. Can't add more dish without widening the guards. Any other ideas...


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  • 2 months later...

did a bit of testing with Simon's ZG flares today. The flares require a little bit of bending to get them on but we did our best.

Tried both flares on as I don't know which are supposed to be right and left. None are sitting perfect, but they give an idea of how they could fit, size wise, etc. It's hard to get them sitting perfect with tape on a dirty car, especially when they are flexing quite a bit.

Rear flare 1



Rear flare 2



Front flare 1



Rear flare 2 & Front flare 1



Front flare 2


Rear flare 2 & Front flare 2


Main issue is that the flares are not circular, more like a slight koru because on the Z the align with the bumper and run down lower on the inside of the arch. This also means that the widest point of the flare isn't always the middle of it, it is where it would sit in the middle of the Z wheel arch, it's most obvious on the front one: flare 1 with the buldge near the back, flare 2 with it at the front. Maybe when they are black it will be less noticable?

Also, I may be able to cut and shut them instead of bending them, but that could be a mission.

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Had another go at placement of the rear one and think I got it sorted a bit better this time. Also moved the wheel out a bit to give an idea of what I'm going for. Note, the inner arch is let down onto the tyre so there will be less gap when it's done. I'm thinking about 10mm. And obviously far more dish.




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  • 2 weeks later...
  • 2 weeks later...

Not much of an update.

Replaced a tierod end. Tightened up both front wheel bearings. Just need to do that axle seal for the WOF.

A mate gave me some black faux leather so I redid my door cards as I was getting sick of the blue extreme.

Next week I'll be swapping my EA Falcon rear discs and calipers for AE101 discs and calipers, brakets are all made up and ready to go. This should pull my track in a little bit allowing for wider, less offset wheels with the flares.

(EA calipers and discs + mounting brackets to suit a Hilux diff will be for sale after this. Recently rekitted. Discs drilled to 4x100 but could easily redrill/get new ones).

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  • 2 weeks later...

Just got a new clutch made. Thought mine was gone but it turned out to just be poorly adjusted. No matter, need a better one for future mad power anyway.

New place with carbon kevlar + clamping pressure uprated from 1280lb to 2130lb. Should be mean.

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  • 7 months later...

Amazing, an update.

I'm out of work, lazing about at home and cam(slacker) encouraged me to go outside and do some work on the car.

Rotated the compressor of the churbro to start an engine bay tidy up and started figuring out how to mount the Chevette bumpers.



It's a bit crooked (I need to slot the side mounts) and the middle mounts aren't long enough to bolt up so will have to tend to that soon.

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  • 2 months later...

A present from Brad:


Now to clean them up. Any suggestions on a centre colour to match the yellow of the coupe?

In other news, massive thanks to Cam (.slacker) for his help in cleaning up the wiring. Managed to get rid of 4 redundant relays and some good progress towards moving some wiring under the wheel arch :) Cheers boy!

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Few pics from the test fit:




The fronts are about 1-2mm outside the guards. The rears will need a 3-5mm spacer to be flush with the fronts.

I see what you mean Brad about the increase in gap and stuff, look at that pic I'm not sure the rear will be low enough at this current level (although the height of the wood was not calculated in any way). Will have to take out the spacers and see what the difference is.

There is a 15mm sidewall difference between 196/50 and 165/50 without taking account for the stretch inwards which will increase that even more. Between 195/50 and 175/50 it's 10mm.

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  • 2 weeks later...
  • 9 months later...

Hey guys, just want some opinion on these SSRs. I've had the lips polished and have stripped the paint off the centres. What colour should I have them painted? I'm thinking of just redoing them in gunmetal. Looking back on these pictures I'm pretty happy with how this looks.

Also, I sold those 165s and am back to using my 195s. Grip over hype.

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  • 5 weeks later...

Alright and we're back.

Lips have been polished, all the bolts have been replated, centres have been stripped and repainted in gunmetal - huge thanks to Levi (LS 2 THE DEEE) for painting them for me.

I haven't put them all back together yet, but here is the first one mostly done:


Image does NOT do justice to how happy I am!

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