My 3.8l V6 Supercharged Gemini

[simc]

Hey guys, just thought I would share my little project with you all. I have had her on the road for 8 years now, but spent about 18 months building it.

I’m sure there are better gemini’s out there, but this was a personal stepping stone for me before I hit a more serious car. I have done everything myself!! Everything was done out of my garage, with my own two hands. Everything from paint, wiring, supercharger setup, interiour trimming, tranny rebuild, exhaust, diff setup.. LOL.. I think you get my drift.


Model: 1979 Holden Gemini, TG update

Colour: Green

Body: 18 month restoration, detailed engine bay, hidden wiring and a few other little changes

Engine: 3.8l VP S V6, with SC14 Supercharger running. TB in front configuration, now on 10psi. 600x300 intercooler, 2bar MAP $5d 2 bar tune, 36lb injectors.

Exhaust: Custom extractors, 2.5” exhaust, 3” dump.

Gearbox: T700 4 Speed Auto, B&M Mega Ratchet shifter, Stage 2 shift kit, Hi energy bands

Diff: VL turbo, 3.45 LSD, custom axels, full adjustable diff tilt and offset, reinforced floor with link points and tail shaft loop, Custom race spec tail shaft,

Brakes: VL Turbo rear, VT 1 ¼” fast fill master cylinder (firewall mount), twin piston callipers on the front with slotted rotors and custom hubs. All 5 stud.

Suspension: Lowered pedders and nolothane bushes all the way round.

Wheels/Tyres: 15” steel interceptors, 2pack micro silver

Interior: Re trimmed interior in VZ cloth, Late TG dash conversion in 2k black, super plush carpet, custom made seatbelts, no centre console to make room for shifter, Rev, Temp, oil and boost gauges mount J

Stereo: Sony head unit, JBL speakers (I like the sound of a roaring engine instead)

Other Mods: SOOO many more, id be here for ever listing them all!!


Performance: So far on 205 50 15” rubber, un tuned on 2.5psi, she has run a 13.6 @100mph, 1.8 60ft. Will probably do a better time on slightly higher tyres as she was running out of revs… but im wrapped with that time. There are a few vids on Youtube. Can't wait to see what she runs on 10 psi

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[Holden202T]

very nice !!!!

im interested to know what you mean about running out of revs ? by my calcs your combo should do well over 200kph before its running out of revs!

either way good to see another delcoed gemini!!

out of interest do you have any pics of the diff conversion ?
keep up the good work!!

[delcowizzid]

love the colour love the charger poking out the bonnet just i hate sc14's LOL maybe you need to poke a turbo out there instead. should be plenty more speed in it yet unless you have silly diff gears im doing 13.9@106 on stock 3.08 at 7psi in a heavy vn wagon.when its finished if i go much lower than 3.45 with boost cranked up it will mang over the line on 14psi with a good launch like everyone else with diff gears like 3.7 and 3.9

[simc]

Thanks guys. The reason I say running out of revs is because it has small tyres on the rear 205 50, and 3.45 gears. This combined with using 3rd gear only gives be about 100mph at 5500rpm (might be slightly out, its been a while). The shift light stays on for the last 50m of the track. I’m not keen to shift into 4th at full steam either. With a higher set of tyres, or a taller set of diff gears should go quicker.

I have tried 3.9’s, and 3.08’s on the street as well. 3.45 feels like a nice combo.

As for the SC14, yeah they are not the best performing blower, but boy do they make some snappy throttle response. Would love a Vortech but they are too overpriced.

I would have went turbo but it’s a tight fit for all the pipes required etc

At the end of the day, I figured a SC14 powered v6 was plenty for 900kg 

I like the sound of your 14psi boost. Tranny holding up?

[antus]

Nice gemmy! Sure does look like a good bit of fun.

[Holden202T]

why don't you want to shift into 4th ? or is it that the gearbox wont ?

mate at work says the way to fix the T700 at WOT is to put a v8 govener in it .... i've had the same problem, i had to back off to about 1/2 throttle before it would upshift into 4th at WOT and even once i got the car going past that speed when i put my foot back to the floor it dropped back and pinged the limiter!

would be interested to see what it would do with the kick down cable disconnected .... would need to hold each gear manually though, but thats not a problem with the B&M shifter.

out of interest have you removed the brake booster to fit the v6 in ?

[simc]

I originally had issues where the auto would not select 4th at WOT. I adjusted the kickdown and managed to get this happening. This was before the charger went on. It dropped the car from something like a 14.5 to a 13.9 Non supercharged with 3.9's in the diff around 91mph. However after the shift kit and charger went in, I was advised by a few tranny experts to avoid 4th, so I reserve it for cruising.

The standrd gemi booster and master cyl can be made to fit in the bay with the V6. All you need to do is offset the standard bracket 15mm to the drivers side. The shaft leading into the booster can handle this angle. I ran it for the first 3 years without issue before the upgrade. CRS who I had no end of dramas with suggested moving the booster to the front of the engine bay, requiring a brake shaft about 1m long. I didnt like the look of this, and didnt like how this would be in the situation of an accident.
With the big brakes all round, it dosen't need a booster. Great feel and heaps of brakes when driving. Requires a little extra effort when stopped at lights but its the sort of thing you get used to in 10 mins of driving. Completely fine for engineering by the way.

I hav'nt got any pics of the diff setup, but I picked up the arms from Mcdonals Brother Racing in melbourne, might be on th website.

[delcowizzid]

you dont want it going to 4th anyway its pretty weak slackning the kickdown just lowers line pressure which isnt good either i just went full manual its great i have plenty rpm left in 3rd same with the vb doing 12.6@109 he has lots of 4th on the manual to go with 3.45 gears he wanted 3.9's LOL will need 5th to get over the line we all run 6000rpm limiters so we can get a lot more speed before hitting it

[Holden202T]

can you not run a taller tyre maybe ? have a race tyre and swap it over for the drags then go back to the smaller ones for the street.

i've geared my gemini (power glide) has the same ratio in top as your 3rd gear does, i have 3.45 diff and at the moment 215/60/15's and it should have a top speed of 190kms at 5500rpm but i doubt i'll get there at the moment!

was much mods to the floor needed to get the diff setup in there ? not sure if you've seen my thread but i cut into the floor and mounted commodore upper control arms into the floor to get my setup done ....