what compression

TGemi1 · tinkerer Joined: 23 Mar 2003 Posts: 456

would i get from a standard recon 1600block with a standard recon 1800 head on it? what psi would u think it could handle through it?

chris...

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

std 1600 (with 1600 head) running an intercooler and in good tune can handle 10psi. don't forget that the compression on a g161 is 8.3:1 which is already low as it is. Some turbo cars run 9:1 comp. if u lower the compression too much your car will be a slug off boost.

TGemi1 · tinkerer Joined: 23 Mar 2003 Posts: 456

it'll be superchargd, do u think 1600 block n 1800 head should b good 4 10psi, would i need a decomp plate? go copper gasket or standard gasket?

chris...

TGNVD247 · tinkerer Joined: 04 Nov 2002 Posts: 470

1600 head and 1800 r the same...

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

use standard 1600 head and standard head gaskets. you don't wanna run too much boost with the blower because the more boost u run, the faster the rotors inside it spin, and i have heard that the rotors in the toyota superchargers (sc12 and sc14) can melt at high speeds. If i were u, i would leave the standard compression and run about 10psi max through the blower with maybe an intercooler or with water injection into the supercharger (which will also increase boost). have a look at a lot of supercharged setups. they are mostly running fairly low boost. u wanna make sure u have ur carby set up perfect too and make sure it doesn't lean out or do any nasty things like that.
good luck...

TGemi1 · tinkerer Joined: 23 Mar 2003 Posts: 456

i dont think a standard gemini engine would handle 10psi, if i intercool it the blower should b fine, would the standard crank and rods etc be right 4 10psi? I'm gettin a g200 head and putting on a g161 block to lower compression so i dont blow the fuck out of it at 10psi. sheel the dude who has done a similar conversion, has used an 1800 block with dish pistons and a g200 head. So i would be fairly safe runing 10psi i hope, i am just thinking if all the standard 1600 internals will be up 2 it?

chris...

Mooch · backyard mechanic Joined: 17 Oct 2001 Posts: 573

1600 and 1800 heads have the same cc chambers. G200 heads have larger ones, so putting one on ur 1800/1600 bottom end would lower your comp ratio. To what degree i dont know, this also depends whether the head ur using has received a shave in a past life from being cooked.

Your engine builder/machinist should be able to calculate your comp ratio using the specs of your head and engine combo. Get ur head cc'd. With salsa adds some spice also. (ok, poor joke)

Also, i beleieve as someone said, too low a comp will make it very "laggy" off boost, and you will need big revs to make boost. They are a small capacity engine so dont go crazy with turbo size.

The G200 head head i think has a different manifold, so this is something you may want to research before getting stuck trying to bolt your 161 manifold onto it if you use it.

Ulitmately, remember it's torque that rules the street so try and create a usable power band between 2 and 5 grand. Not only is this more sane, things are alot less stressed at 5 grand than at 7 - reliability!

For strength you can't go past a g200 bottom end over the 1600 and 1800's. They have better rods, and also have the benefit of a flat plane crank (same as ej20's from the wrx and porsche boxer motors). The longer stroke helps bottom end and midrange torque, also will suit due to the power band you will be trying to achieve.

Invest in a desk top dyno programme such as "dyno 2000" or similar. A decent machine shop or engine builder will have one of these and they are vital for determining what components are needed to "match" for an engine combo. No point bolting in all these expensive bits if they don't work well together.

Remember, torque rules the street.

Cheers
Mooch

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

when i was considering turboing/supercharging my engine, i was speaking to a family friend of ours who is a mechanic. he's turboing his pt cruiser in his garage and said that 10psi on a standard engine would be no problems if it was intercooled and tuned perfectly running on premium. the standard bottom end should hold up alright, but of course for long term reliability and even higher boost, forged pistons and stronger rods would be better. if you don't want to use an intercooler (front mount) then try water injection. im not sure how much it costs but it would be very effective.