Super Charging a G-series engine

[SHEEL]

Hi all,

obviousely with all custom modification everyone uses different methods, and has preference to hardware manufacturers... so keeping that in mind this is what i have done so far with my project. hope someone can find it useful.

i have used a toyota s14 supercharger, it is a positive displacement, twin 3-blade rotor blower. it produces full boost very low in the rev range but wont boost harder the more you rev. ( i.e. it is a good producer of torque ).
This supercharger is origonally from a toyota 1G-GZ 2Ltr. six cyl. engine from a toyota crown. you can source it from most importors. i got mine from EKW in melbourne.
they sell for just under $500

You cant just bolt this up to a stock motor so make sure ur donk is up 2 it before you even bother. i have used a freshly rebuilt g180 with dish pistons and the bigger g200 head, compression is around 8.0:1 as opposed to the standard 8.4:1 in the rodeo. Also, do not use an aftermarket Cam u would normally use in a N/A motor, forced induction does not like long duration lobes. use a stock cam or have one specially ground for the blower application.

the simplest an cheapest way to drive this blower is to remove the pulley and have a new one made to suit the vee belt on your gemini. I went to a bearing shop and bought a blank pulley(no centre hole) the same size as the old flat belt pulley. then i took the blank pulley to a machinest so he could machine a hole with the splines to match the drive shaft on the blower. this whole process should cost you no more than $100.
However, this process does not allow you to utilize the clutch set up on the blower. it is dedicated drive only.

roughly position the blower on the right hand side of the motor looking from the front of the car towards the engine bay. if you have a later model gem all the air pump shit must be removed first,and you have to relocate your battery to the boot. Also keep in mind clearance from the bonnet, exhaust man./extractors, and side of the engine bay. make sure the pulley lines up with the pulleys on your engine. when you are happy with the postion of the blower start measuring to make your brackets. i mounted my top bracket from the side of the head where the air pump was on the later model head, if you have a pre pollution head you will need studs fitted in the blank spots there.
I mounted the bottom brakets from the bottom alternator bracket where it joins to the block.
make sure you use thick steel like at least 5mm by 8mm it must be strong enough to cope with the twisting motion of the blower.
by the way, you need a welder to make the bracket in case you didn't figure that already...

i mounted the blower in a fixed postion then extended the altarnator top bracket to retain the alternator as the belt tightening point.

of course then a bigger belt is needed i used a 13A 1270.

with your blower mounted start your engine to ensure that the belts all work properly( i.e. they line up, don slip, ect.)

now we get to the fun part...fuel supply. there are many methods/applications to use and each has thier benefits and downfalls. there are some general rules that apply to all though. You CANNOT push against a throttle body with a supercharger. so you must either use a draw thru carb set up or use injection with the throttle body mounted before the blower.
injection is the best way to go of course but u have to source an inlet manifold, computer, sensors and all that and it generally costs more.
using injection allows you to run an intercooler if that tickles ur fancy.

drawing thru a carby/s is cheaper in most cases but not necessarily easier with twin carbs, tuning can be tricky and should be done on a dyno. if your car is not tuned properly it can lean out and destroy your engine very quickly.

in either case you must get a new throttle cable made or dodge somethin up.
also fuel lines, induction pipes, some wiring, must be changed to suit.
I am using twin side draft SU's from a torana for the moment but i'm currently making the pipes to bolt them up to the blower. so i'll update this post in the next few days to say how that goes.
Also you cannot run vacuum advance for your distributor, i dont know how to get around this yet so i'll update on that also.
more updates and info next week if all goes well.
Sheel out.
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[Loz]

About the cam. People that built my engine and many other gem engines, tend to use a stage 1/2 (in the vicinity of a 26/66) cam for turbo engines, which would be the same for superchragers. This allows the engine to breath a bit better and wont have too much duration. It is also alot cheaper than a custom ground one. However a custom one would be a bit better.

Loz

[thanomis]

Do not post a reply in this forum if you do not have something of value to add, note that something of value can be an *intelligent* question to clarify a *relevant* point.

(Note: For those that missed it, the guy posted in here saying "Hey you sound smart, can I have your email address?")

[Racegem]

You should be able to run the puffer before your butterfly if you run a blow-off valve.

Take your dizzy to a dizzy specialist and have them modify it to full mechanical advance and recurve it to suit.

Cheers, Yonnee.

[Gene FJ20DET]

thats what i was thinking. i read somewhere the blades in the toyota blowers (teflon? or something) dont like being run with a suck threw set up after to long
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[Gene FJ20DET]

opps my bad.
says its ok. see here--->
http://board.performanceforums.com/forums/showthread.php?s=&threadid=67149416

but if u ran a BOV i cant see what a blow threw wouldnt work?
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[SHEEL]

Damn you guys. now i've changed my mind, i'm ditching the draw thru setup in favour of a blow thru setup using a weber. with a BOV of course. it should be alot easier i think.
Sheel out.
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[TGemi1]

hey sheel, how much money all up do u reckon it'll cost 4 yours to b running? standard engine?what mods?

chris...

[SHEEL]

probably in the vicinity of $700 maybe a bit more...
engine is rebuilt standard with factory spec dish pistons,and a g200 head with the 1800 double valve springs.
compression ratio is around 7.8:1. the steel crank is very capable as are the rods in a g-series engine. a standard engine will be strong enough provided it is tuned properly.
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[hypaTG]

how much hp is the blower rated at? I am thinking about supercharging my 12a with that blower
cheers.

[SHEEL]

i don't think blowers are rated like turbos are, u must take into consideration that it takes some power and torque from the engine to drive them. this will be different for each engine so it cant be said. however, work can be done to these blowers (better bearings, modifying the inside of the case, ect...) so that you can overdrive them for more boost. so my suggestion is to try it out and if your not happy, fit a smaller pulley to run the blower harder.
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[Gene FJ20DET]

if u put a bigger pully on the engine side would it give you more "go go" power form the blower as it would spin faster and quicker?
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[TGemi1]

it would only spin as fast as the engine is, not matter if the pulley is bigger or smaller

[Gene FJ20DET]

if u have 2 pullys, 1 with 10cm dia' and 1 with 20cm dia (for examply) and u turned the center at the same speed for each,the 20cm dia' pully would spin the belt alot faster, cos of the bigger diameter. its like gearing the cogs on a moto bike or pushy.
i wanna if by the belt spinning fasted by using a larger pully, would it creat more torque for the blower or would it not make any difference
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[SHEEL]

good point gene. but i'm gonna use it against you... hehe. just like on a push bike when you put a bigger sprocket on the driving side, it takes more effort (torque) to drive it, but yes it would go faster. therefore it would create more horspower at higher revs, but u would loose torque at the bootom end of the rev range.
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