power gains?

slinky · rice boy Joined: 22 Oct 2002 Posts: 32

what can i do to get some reasonable power because i rang up about a 12a rotar and they quoted me 6500$ my buget is a tad lower than that so since i cant do that i was thinking twin webbers big cam what would you sugest its a 1.6 with 2inch exaust extractors new plugs leags and other little crap?
any help please?

hypaTG · backyard mechanic Joined: 15 Oct 2002 Posts: 524

i am guessing that price would be for a fully rebuilt 12a with new seals, springs and shit. you could get a 12a (carby engine) in the car with the engine for about $2000. you can get the engine for about $1000 for a decent one and then you need a new sump, crossmember and stuff. you can get much more power out of a n/a 12a than u can out of a n/a g161.
however, if u want to keep the g161, put some twin 40mm or 45mm carbies, cam, port and polish, bigger valves, deck the head, overbore the block and fit g180 pistons.
that should go pretty hard but a 12a with extend port, extractors and exhaust will probably blow its doors off.
it all depends on the cash tho... god dammit!
hope that helps a bit,
good luck,
mat

Simon · rice boy Joined: 16 Feb 2002 Posts: 47

for about half that much, you can build your 1.6 with the extractors and exhaust to make around 145hp at the fly, or 125hp at the wheels, and trust me these are fairly quick little motors..1.6 bored and stroked to roughly 2l using 2 litre mazda crank and pistons, stage 2 or 3 cam, all new bearings, head work, ported polished, its basically the works.....scares a few bigger engined cars thats for sure
hope that helps a little
Simon

hypaTG · backyard mechanic Joined: 15 Oct 2002 Posts: 524

a 12a with 2.5 inch exhaust and extractors and carby mods (bored out choke, modified linkage system) will put out about 120rwhp. extend port and you might get about 170rwhp. someone ran a 12.9 or 12.7 with a 12a J-port in a car that weighs about the same as a gemini. it all depends how much money you want to spend... im a bit biased towards rotors though coz i've got one, plus, you get the awesome sound they make. brap brap brap Smile

simon's idea for the g161 would go nicely too, just add a bigger carby or 2 and you'll be flying. a car recently in hot4's ran a 13.9 with a 1.6, it had twin 40mm webers, balanced, blueprinted and deburred bottom end, forgies, high comp and all the rest of it, so that proves, those engines can make power if you want to spend the dosh on them
good luck,
cheers,
mat

DrIFtA · tinkerer Joined: 13 Mar 2003 Posts: 246

Where/what are your foundations for using the 2 litre Mazda crank in a G16Z ?? I'm extreeeeeeeeemly keen to know how an engine from a different manufacturer carries a crank that can be used in a Gemini engine. Dont you think that the offsets, journal size, counterweight sizes, and not to mention length would be a slight itty bitty problem. You haven't mentioned whether mods have to done to accomodate this item, as if it's a bolt in deal - not even a simple 'you will have to get it slightly offset ground to help it fit'.
I could see how you suggested the Mazda pistons as maybe their diameter and skirt size is not a problem, just like i have been told (by people that have actually performed it) that VL Turbs pistons slot into a G18Z as they share the same bore size (86.5mm from memory).
But the Mazda crank idea, c'mon now, please elaborate on what mods (if any) and who fitted it and which Mazda 2 litre for that matter.
I think it's safe to say that everyone here at HotGemini.com including myself are very eager to find out and learn how this mod can APPARENTLY be performed.

P.S
the only time i have ever heard of this kind of crank interchangability is with the Holden 179/186/202 etc, there is a stroker kit avaliable which carries the Ford 221ci crank. This has to be modified via cutting the end off and re-welding the Holden item onto it, then it has to be offset ground - very costly and only an option if you have a soft spot for working the Holden six in favour of fitting a V8.

L8TRZ

GeminiCoupe · tinkerer Joined: 10 Jan 2003 Posts: 172

"VL Turbs pistons slot into a G18Z as they share the same bore size (86.5mm from memory)."

g180z has 84mm bore and 82mm stroke - taken from workshop. Ive also measured the bore on mine and its 84mm. were VLT pistons availible in 1mm oversize? (to suit an 87mm bore)?

if they were, then they would sound a G200z perfectly

cheers

TXcoupe · petrol head Joined: 05 Oct 2001 Posts: 1675

they would fit in the G180Z but would have to bore it 100 thousandths of an inch or 2.5mm. Thats not too bad better than trying to slot G200 pistons in the G180

tx1975 · tinkerer Joined: 21 May 2002 Posts: 321

ok to let u all know, vl piston are full floaters and by the time u machine out the gemini rod and bush it it looses a heap of strenght and shouldnt be used in high power engins, just get forgies for a gemini to start with or u will be asking for trouble.

TXcoupe · petrol head Joined: 05 Oct 2001 Posts: 1675

yeap cool thanks dudfe

btw u have anyseat rails to suit a TX?

tx1975 · tinkerer Joined: 21 May 2002 Posts: 321

what tx, early or late model. i dont have any rails but mine are early and go through the floor pan which are almost impossible to find working ones , or late model like all other gems which are easy to get.

TXcoupe · petrol head Joined: 05 Oct 2001 Posts: 1675

yes mine is early to the seat bolts to the floor, I dont mind if they dont work i just got to put in a another seat for sponsors thats all

DrIFtA · tinkerer Joined: 13 Mar 2003 Posts: 246

"VL Turbs pistons slot into a G18Z as they share the same bore size (86.5mm from memory)."
hehehe, sorry, i should have at least looked in the workshop for the right dimensions. 84mm must be right if you've actually measured the bore. I had 86.5mm stuck in my head for some reason - may have been chatting to someone recently about another engine.
In the industrial area that i work in, i get litteraly dozens of mechanics and engineers come through and i chat to them about my options, and what prices they can help me out with. Approx 8 to 10 of them have told me that they have used the VLT slugs in G18Z builds, and not one of them to date has has mentioned anything about them being full-floaters. The way they said they went in was as if they bolted in no fuss. So maybe, they have done them that many times that machining and bushing the rod is just second nature to them. I'll have to hit them up about it now hehehe.
L8TRZ

Knobby · tinkerer Joined: 09 Oct 2001 Posts: 172

i got some early model tx rails, where abouts are you?

TXcoupe · petrol head Joined: 05 Oct 2001 Posts: 1675

im in WA dude email me and send me pics too

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

hey I have VLT slugs in my G161 Turbo, 3 yrs 18PSI not a problem, yes you have to bush the rods, but the are so stong it doesn't matter...
costs about $40 to have them bushed and pistons fitted,
cheers