Supercharger for Subaru?

Silverbullet · Post by **Silverbullet** » Tue May 08, 2012 6:09 pm

Sounds all good in theory, looking forward to seeing what happens with this

Tweety · Post by **Tweety** » Tue May 08, 2012 9:52 pm

Yes silverbullet. I am eager but will take my time more than when I did the conversion.

And I'll document and photo everything. One thing about this supercharger thing is that info on the web is limited. Photos etc are not easy to come by.

Be good to have the project step by step detailed for others to follow if desired.

steptoe · Post by **steptoe** » Tue May 08, 2012 10:10 pm

I think it is high time you bought a real , complete Subaru as a test bed for your supercharger - like I did with my sedan , still driving it 65,000km later and project turbo Brumby still a dream (more like a engineer cert nightmare coming up ! )

Tweety · Post by **Tweety** » Tue May 08, 2012 11:08 pm

Nah Steptoe.

Am a light on type. Dont want unwanted car bodies or parts lying around. Cant see your point though. And already have 5 regoes and insurances to pay.

My only real concerns are the dizzy weight locks or what ever, recalibration etc, the making of the connections from the sc to the inlet of the manifold and the rest is a little research and planning, searching wreckers and auto shops for bits. and finding a carbie but I might hook up the weber first and see how it goes.

A supercharger being bolt on accessory I believe doesnt require an engineers certificate. Am I correct?

steptoe · Post by **steptoe** » Wed May 09, 2012 8:36 am

if it changes your exhaust noise and emissions - likely yes, will need engineer unless trikes have another sneaky exemption. i think utes also have a sneaky advantage over passenger cars in this regard.

As for the dizzy mods you no understand, it is a term my gas guru refers to as 'staking' . Weld or braze up the mechanical advance internals so there is no mechanical advance. Was suggested if I turbo'ed my EA81 on LPG that we'd do just that and set dizzy at about 16 BTDC static. Have read of others using similar figure - for LPG applications

Five regos and insurances! If only it was a day in the future, state laws and governments gone and just a national drivers licence, registration etc - club members could band together and approach an insurer etc for group discount, add the squeeze it is impossible for one or two people to drive five vehicles at a time ......

Tweety · Post by **Tweety** » Wed May 09, 2012 2:27 pm

ok, the best site yet for the basics of installing and understnading a supercharger. If you want to know more about them then this is the site.

Interesting was that V belts are fine and I have a double crank pulley (they will slip a little on backfire). A tensioner on the rear "flat" of the V-belt would be ok with approaprite bearings and high sides. The preference would be to make the SC adjustable.

Of course my crank pully is 150mm in diameter. For 6psi I think it should be 120mm. so I will get extra unwanted boost. (bit like big boobs too much waste). Now as I need a v-pulley on the SC clutch I will need to look around for one that will be bigger.

If the SC was moutned so it was adjustable my only problem would be the manifold from the SC to the intake. If I fabricated plates for both ends can I buy say a ribbed flexible hose say 100mm diamter and 100mm long to conenct them?? bearing in mind I might need a BOV?

and. I'll need to upgrade the fuel pump. was thinking if I had a return that went to a 'T' peice between the tank and the pump I wouldnt need to tap a hole in the tank itself and the excess fuel would just blow into the tank in reverse to how it flows now for a short time until fuel is needed again.

Aslo he explains the benefit of the sU carbie over others. Very interesting and hard to find info on this on the net. maybe this site should be a sticky??

Thanks to Eldred Norman.

got a headache/

http://www.fefcholden.org.au/techinfo/s ... man10.html

Bradenrm · Post by **Bradenrm** » Wed May 09, 2012 6:43 pm

How big are we talking, though?

Tweety · Post by **Tweety** » Wed May 09, 2012 7:01 pm

How big what Bradenrm???

Detail mate...not enough detail? fuel pump, SC, pulleys????

Tweety · Post by **Tweety** » Wed May 09, 2012 10:14 pm

Taken from another site and changed calculations to suit the 1781cc ea81.
When fitting a supercharger, you should match the swept volume of the supercharger to the size of the engine. If the choice is made carefully, problems from overboosting and the required paraphenalia to solve these problems will be minimised.

The supercharger will also be kept in its safe operating speed with correct selection.
Bear in mind that the faster the charger spins the more heat. And over 6psi you should install an intercooler.
To choose a setup you need to know :-

1. Engine capacity - 1.781cc ea81
2. Maximum engine speed you will be using. (Ah 5500?? or 6000??) 5000 ea81 (Based on information that max power for the standard ea81 is made at around 5000rpm) and I want it to last.
3. Boost level desired (eg7-10psi) 6psi

The calculations are:
1/ FIRST CALCULATION (Engine Litres/min @ 0 Psi )
Multiply engine capacity (in litres) times maximum engine Rpm. Ea81 1.781x5000= 8905 litres/minute. Divide this figure by two as engine only fills every second stroke.
8905/2 = 4452 litres/min.
This is the engines air requirements in litres/minute at 0 Psi boost.
2/ SECOND CALCULATION (boost ratio)
Add the boost pressure desired (6 Psi) for the engine to 14.7 Psi (atmospheric pressure).
(6 psi boost desired +14.7 =20.7 psi)
Divide this answer by 14.7 and this gives the boost pressure ratio. (20.7/14.7=1408) This is the boost pressure ratio above atmospheric pressure. 20.7/14.7 =
1.408
THIRD CALCULATION (Actual air requirements @ desired boost)
Multiply the boost ratio (1.408) by the litres/minute obtained for 0 Psi (4452)and you get the actual air requirements in Litres/min for the engine at that boost
6270 L/min ea81 for 6psi boost.
So now we have the following:

- Engine litres/min @ zero psi is 4900
- Boost ratio is 1.408
- Actual air requirements @ desired boost is 6269 for 6psi

To decide on the correct size of supercharger you need to know :-
1. The swept volume per revolution of the supercharger. SC12 is 1200 litres/rev
2. The maximum continuous safe operating speed for the supercharger. (Ogura’s site says SC12 11,000 rpm ea81 but to be safer say 10,000)
3. The maximum pressure that can be safely produced by the supercharger continuously on the SC12 is about 11psi with bursts up to 14psi for short periods.
CALCULATION (Supercharger rotor speed)
Divide the desired air flow 6270 L/min by the swept volume of the supercharger (SC12 1200 L/rev). This will tell you the maximum speed the supercharger rotors must be run at to produce the volume required.
6270/1.2 = 5224 rpm
CALCULATION (Pulley size ratio)
Divide the rotor Rpm 5224 by maximum desired engine rpm 5000 to get the drive ratio of the pulleys. (ea81 5224/5000 rpm @ 6psi = 1.04) near enough to 1:1. The ea81 crank double V pulley I have is 150mm diameter. I can use a second 150mm diameter pulley on the SC to get boost of 6psi at 5000 rpm.

In reality if the SC was a shell shape and narrow it could be bolted to the crank directly (with a hard rubber connection somehow). If the calculations are correct then a pulley set up on the ea81 the same size on crank and SC will provide 6psi. Reduce sC pulley size or increase crank size to increase psi.

Considering 1 bar is around 14psi. and according to Stenno's mate that would double the power then I could be on track for 35% power increase. I'd be happy with 20-25% and increase in torque at lower revs.

Any alterations you think are required let me know and I'll edit as this could be a formula used for supercharger planners.

Tweety · Post by **Tweety** » Sun May 20, 2012 8:50 pm

Purchased two Dellorto 400 side draught carbies tonight. One is fully refurbished the other has had a kit through it and at this stage will be set aside.

Should get the SC and carbie this week.

steptoe · Post by **steptoe** » Sun May 20, 2012 10:24 pm

DANGER WILL ROBINSON , DANGER friggin' hell, you are going through with this aren't you

Tweety · Post by **Tweety** » Sun May 20, 2012 10:36 pm

Yeh Steptoe....once I've done with the investigation of its feasibility, read up as much as I can about the install, then I go ahead.

Yes, I would have prefered to buy a Sprintex SC, more compact, new etc etc but I've spent a lot on this trike. Will take some chances with the SC12.

One dilemma is about the engineers certificate. I have lined one up for the ea81 conversion but put it off because of my SC plans. Dont know if I should go ahead and install then get him to do his stuff or get the vert and treat the SC as a bolt on accessory. Dont know what to do which way to go.

Will post pics in next few days of the bits.

Yeh, am excited. Might be back to two wheels soon afterall....eg wheel stands!

Silverbullet · Post by **Silverbullet** » Mon May 21, 2012 7:10 pm

If you are still researching feasibility please give Steve at Rising Sun a call here in Adelaide, he seriously knows his stuff and he could tell you not only if it's feasible but also the best way to go about it and probably the best way to get it certified as well. Might be a costly phone call but if you can get a few minutes of his time it will be well worth it.

I'm watching with much anticipation, good luck

Tweety · Post by **Tweety** » Mon May 21, 2012 8:24 pm

Cost is well worth it and will do very shortly. I am beyond the feasibility....now am committed. But as the trike is operational I want for it to remain so for as long as I can before the install. So I might be taking my time on this one, but I've said that before. Am a doer not a dwindler. Then again the winter here...-3 last night.

I'll give him a call.

I have been reading Joel's thread on aussieveedubbers. http://forums.aussieveedubbers.com/view ... 678&page=1 and taking it all in. The ea81 I've decided to not go to the trouble (trouble for me) in swapping the manifold for the larger ea82.

I have to block off the trillion vacuum ports on that manifold rather than the rubber caps I've been using, reassess the alternator location in view of the V-belt set up I'm going to use (wrap around large footprint of belt on SC pulley) source a fixed v-belt pulley of the size depending on which of the two spare pulley sizes I have on the triple crank pulley etc. A single V-belt isnt out of the question either. Belt tensioner....the list seems daunting but I know i can do it. I really dont want the SC poking out too far out the back.

But I'm heartened by the central ea81 manifold intake rather than the pipes necessary for Joels VW. And I'll source a BOV. manifolds will be interesting. My arc welding resembles a tray from a chook farm yard so after tack welding its off to my engineer (the roof builder) to do a good job. Then to chrome them?? depends.

Tweety · Post by **Tweety** » Tue May 22, 2012 5:58 pm

Received my SC12 Toyota supercharger today in the mail.

Impressed. It appears internally to be very sound. No slop at all in the bearings. fair bit of dust on the rotors so am wondering what to clean them with as dont want to take any teflon off. ???

and the end casing was clean ready for some new oil. 2x (100ml) Holden supercharger oil will be ample.

Dellorto carbie will be here soon.

Tweety · Post by **Tweety** » Tue May 22, 2012 10:51 pm

Be interesting the increases??

YouTube · Post by **El_Freddo** » Thu May 24, 2012 3:27 pm

Awesome mate! I'm looking forward to watching this conversion unfold!

Cheers

Bennie

Tweety · Post by **Tweety** » Thu May 24, 2012 4:21 pm

Been in touch with my VASS approved engineer (very few Vicroads ones around for trikes). He told me that he would prefer to do the check over after the supercharger is installed.

What does this mean????

GO FOR IT!!!!!

but I'll leave the extended wheels out the back and the nitro bottle off for now...

Can anyone tell me the easiest way to remove ground in grease from aluminium housing?? tried degreaser, metal polish etc- not effective enough.

Silverbullet · Post by **Silverbullet** » Thu May 24, 2012 6:32 pm

Wire brush in a drill? I did that on an engine block and it came up looking really great, for about 24 hours then it went dull grey

Was still clean though

BaronVonChickenPants · Post by **BaronVonChickenPants** » Thu May 24, 2012 7:54 pm

Clean with petrol, then polish with brasso. To maintain the shine seal with clear coat, preferably 2pac.

Jordan.