confused on horse power

super charged gem · rice boy Joined: 16 Dec 2001 Posts: 15

i have tg gemini with an 1800cc bored out to 2200cc with the head ported and polished and a compression ratio of 13.6:1 with a fairly solid cam and a single twin barrel 50/56 webber 2 inch into 2 1/2 inch extractors with 2 1/2inch exhuast with a standard 3sp auto with a 3500rpm stall converter and a locker diff been on the dyno got 103bhp at 9300rpm but after 7500rpm no power gain it does a mid to low 14 sec quater mile time, 0-100kph in about 6 secs give or take. Does the horse power seem right for whats been done to it? cos most ppl i talk to recon with whats been done i should have more horses anyone with any idea no fuckwits pls tell me what you think!

Slug · tinkerer Joined: 06 Oct 2001 Posts: 196

ROFL thats funny .. I think you should have a least 500 HP with that set up ... sure it not bored out to a 3 litre ..... Michael

Fastgem · tinkerer Joined: 04 Oct 2001 Posts: 166

Wow!! a 50/56 weber! I was going to buy one of those for my gem. If only they actually made them.
If its not making anymore power after 7500 maybe it leaning out? Get a 200gph fuel pump and bump the compression up to 16:1, just use a cam with a little bit of overlap, should be able to run super no worries. Maybe you should also think about adding a 600hp+ nitro kit? They bolt strait on.

Mark · tinkerer Joined: 04 Oct 2001 Posts: 153

60thou over 2 litre would give you roughly 2000cc. Howd you manage 2200? Even a standard 2 litre struggles to keep a head gasket intact at 10:1 compression for more than 6 months, and thats the biggest bore you can have and still fit orings. On top of that ive built a twin cam that runs 12.75:1 compression and that involved dome top pistons and chamber filling, and orings in a standard bore 2 litre with twin 44mm downdraught webbers running on c16 fuel, and that rolls 164hp at the wheels aspirated. I think you're talking out of your arse buddy.....

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

I have to agree with Mark on this one, I also have a tg van 2ltr +40thou flat tops about 11.5:1 comp non fly cut pistons, balanced bottom end twin 40mm webers side draft as big a Camtech cam as possible without bending valves, Felpro steel headgasket, running on a mixture of avgas & PULP, 5spd and 9 inch lsd diff, this sucker makes 110 bhp at rear wheels @ 6500 rpm no point reving it above that as the cam does not make any more power. and keeping a headgasket together under full load is an interesting issue.

even my turbo low comp does not rev above 7500, god only know why you want to rev to 9500 unless of course you want to launch pistons into outer space, your power figures are about right for your combo, try some octane booster, and advance your timing alittle, try some jetting / fuel mixtures / timing on a dyno, or even ditch the auto as it will eat plenty of HP, i would not bother with NOS or methanol in the way of fuels as you will not be able to contain the bang with bores of that size as there will be nothing between the walls of 1&2 and 3&4 for the headgasket to hang onto, any way good luck.

Gene FJ20DET · Posted: Mon Dec 17, 2001 11:57 pm Post subject: Re: confused on horse power

just one question?!!? why an auto??
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Gene FJ20DET · Posted: Tue Dec 18, 2001 12:02 am Post subject: Re: confused on horse power

dont forget the chrome exhorst tip!!!! i heard they add 50hp no trouble!!
when i put my sports steering wheel on i got an extra 25 hp aswell!! i would advise both!!
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Mark · tinkerer Joined: 04 Oct 2001 Posts: 153

autos are stronger when built to suit, change gears faster and smoother, easier to use with any sort of forced induction as they maintain boost or nos pressure better and with a suitable stall converter (4000 upwards) will launch as hard as any manual. Thats why.
Downside is they take more power to run em.

super charged gem · rice boy Joined: 16 Dec 2001 Posts: 15

first a 2lt IS 2000cc and i never said i didnt have a problem with blowing head gaskets but they generally last longer than six months and the 50/56 webber is not standard it was modifyed i bought the car from a perfomance engine builder it was used as a show car till it got smashed and i all ready have the sports steering wheel and tip but it dont make much of a difference i dont where you got yours from but i want one if you dont belive ill have my ps in feb if you want to come down to cranbourne ill give you a show of what it can do up to you

RJM · tinkerer Joined: 10 Oct 2001 Posts: 109

Do ya self a favour and get a pair of weber IDF 44 carbies and a manifold to suit. Maybe them it will go faster than a snail on horse tranqilizers.

Mark · tinkerer Joined: 04 Oct 2001 Posts: 153

a 2litre is 1958cc dickhead, and an 1800 is 1858 cc or so. 3mm overbore gives 100cc approximately (87mm bore 2litre, 84mm bore 1. Cool

. To acheive 2200cc you will have to bore out an amazing 10mm or more from each cylinder, considering thickness between the siamezed cylinders is around 7mm on a 2litre motor I think you're doing something pretty dam special.

henry · rice boy Joined: 17 Oct 2001 Posts: 22

Just a quick question boyz .. if i have my g180 bored 40 thou whats the capacity after the bore?

Mark · tinkerer Joined: 04 Oct 2001 Posts: 153

At a guess id say about 1885cc ish

Slug · tinkerer Joined: 06 Oct 2001 Posts: 196

1861cc ... Michael

Slug · tinkerer Joined: 06 Oct 2001 Posts: 196

you will nee a bore of 93 mm to give you a tad over 2200cc (2227cc) ... Michael