Supercharger for Subaru?

steptoe · Post by **steptoe** » Wed Aug 01, 2012 9:12 am

rubberised cork if it is available in sheet

your ...er...I mean , Tweetys blow off valve only operates for back fire protection, unlike the WHOOooosh of turbo blow off in non plumb back ?? I know Tweets is plumb back.

Post by **TOONGA** » Wed Aug 01, 2012 9:19 am

Tweety the engine side of the eaton superchargers (compressed air into engine) use a "teflon gasket" from what I seen in images of these gaskets they are quite thick and reusable.

My suggestion of cork, rubber or even silicon; comes from me being in the local parts shop where I saw 3 different types of flat gasket paper. The cork one reminded me of the rather large roll my uncle had on his farm, that got used for every gasket under the sun.

Remember that when superchargers work, the lobes even though coated with teflon rub against each other and the gears as well generate friction, this creates heat which causes expansion and warpage. In theory a thicker gasket will allow for expansion and contraction with less warpage over time. The only down side to a thicker gasket is age failure due to pressure leakage.

I'm closely watching your progress because if my plans for a draw through turbo don't come about I will be looking at a small supercharger for PJ.

TOONGA

Tweety · Post by **Tweety** » Wed Aug 01, 2012 11:13 pm

Thanks guys.

Well my engineer had "linished" the manifold face. Whatever that means!!!??? anyway its flat. I then went to a garage and the old guy only had one gasket- about 1.5mm flat gasket rubber on both sides and thin strip of alloy in the middle sandwiched. This I gather is what you are refering to Toonga?

Enough for 3 gaskets for 10 bucks when I got home I threw a small peice into the wood heater and stood there waiting for the hot coals to burn it. bloody hot fire it was too. Some 45 seconds later it started to burn but it was a slow burn. Meant it is ideal I think for the purpose.

Then I bit the bullet. A couple of the mounting holes on the SC had worn threads. I tapped them out to take larger bolts. Cut several peices of continuous thread (try buying studs nowadays in the bush even repco dont sell them anymore) and made my own studs making sure they didnt go too far itno the Sc and protrude to the lobes. Some locktite and its done. I didnt want to tighten the nuts to compressed that gasket only to strip a thread and more work. The manifold was placed on the SC and there is only the tiniest movement say half a mm that the gasket has to take up.

Can I use gasket goo with this rubber gasket Toonga? Or isnt it required?

Here are some pics....me knows you guys like pics....

Tony

The gasket with rubebr on both sides of alloy sheet

The two manifold halves in situ

Note the black top mount needed now tha tthe mnaifold is in two halves

A shot of the tensioner on the "slack" side of the belt.

The shortened lynx manifold.

Here is the airbox. From Middy;s electrical. its a wire box and the clear cover allows seeing the foam socks.

Here it is in its future position. The socks havent got their zippers on yet which will give move room for air. there is a cold air intake to the front of the rear wheel

These trumpets that came with the refurbished carbie bought on ebay had to be cut to accomodate the socks

This is the magic "Devcon". This is plastic steel. mix 1 part to 9 hardener and you have a black goo that you line your manifold with, fill cracks, smooth out crannies to make the fuel/air mix easier to travel through the intake system. I even used it at the end of the airbox to seal joins. Great stuff. Expect to pay $140 for 500grams. I was lucky and got it on special at Blackwoods for $91.

Tweety · Post by **Tweety** » Wed Aug 01, 2012 11:16 pm

Post by **TOONGA** » Thu Aug 02, 2012 9:26 am

Tweety thats exactly the sort of gasket you need and yes you can use gasket goo, rtv hi temp silicon or any other sealant available as a "gasket helper".

It is all looking rather finished now I'm hoping it works really well and that the next dyno session brings it all together for you.

TOONGA

Tweety · Post by **Tweety** » Thu Aug 02, 2012 9:47 am

Thanks Toonga. Yep, I'll use a little gasket goo, the black tar stuff, just a smear.
I rang my dyno tuner at VW performance centre and he kept my spare jets and agreed the 225's would have been needed due to air leaks. So I'll hopefully get a nice enough idle when assembly is completed to get down there and get it done.

YouTube · Post by **El_Freddo** » Thu Aug 02, 2012 7:25 pm

Looking good mate!

Hope it all goes well with the dyno!

Cheers

Bennie

B00sting · Post by **B00sting** » Thu Aug 02, 2012 8:30 pm

What do you guys think about the raptor supercharger kit for ej20, 25s?
http://www.raptorsc.com.au/kits.php?id=20

YouTube · Post by **El_Freddo** » Thu Aug 02, 2012 8:45 pm

B00sting wrote:What do you guys think about the raptor supercharger kit for ej20, 25s?
http://www.raptorsc.com.au/kits.php?id=20

From what I've read they're good but I'm not sold on the cost of the kit. But then again, that's just me!

Cheers

Bennie

B00sting · Post by **B00sting** » Thu Aug 02, 2012 9:04 pm

I was curious to know if anyone on here had used a kit. Considering it but thats another legal hurdle I need to research.

Tweety · Post by **Tweety** » Thu Aug 02, 2012 9:53 pm

Interesting. Bang for buck its cheap. But cheap if you have the cash and expensive if you havent I suppose. for 7-9psi boost its amazing the output increases engine get.

There is a real arguement for NOT going any further on boost with non ecu engines. Reliability as most engines arent upgraded internally to cope with higher boost, more heat which could cause other issues, detonation, etc. Interesting that my ea81 hasnt had any detonation yet. Towing will bring it out if at all.

With ECU FI engines these may not be issues at all- wondering? So I assume you could set this system up on your EJ20/25 and later get a smaller SC pulley and increase your boost and the piggy back ECU will cope automatically. I'm asking/wondering.

steptoe · Post by **steptoe** » Fri Aug 03, 2012 9:02 am

With Twety, detonation may be a worry not only towing, but summer heat and towing, and up hills. Ask yer tuning mates if they want you to come back in the heat of summer for a check up. A little richer may help, may not....

B00sting · Post by **B00sting** » Fri Aug 03, 2012 10:01 am

Tweety wrote:Interesting. Bang for buck its cheap. But cheap if you have the cash and expensive if you havent I suppose. for 7-9psi boost its amazing the output increases engine get.

There is a real arguement for NOT going any further on boost with non ecu engines. Reliability as most engines arent upgraded internally to cope with higher boost, more heat which could cause other issues, detonation, etc. Interesting that my ea81 hasnt had any detonation yet. Towing will bring it out if at all.

With ECU FI engines these may not be issues at all- wondering? So I assume you could set this system up on your EJ20/25 and later get a smaller SC pulley and increase your boost and the piggy back ECU will cope automatically. I'm asking/wondering.

Yeah it seems to be 4100, or 5800 intercooled. The fact that it's all plug and play makes it worthwhile. I've done a turbo conversion before, the amount of bits and pieces and running around we had to do was amazing, not to mention the aftermarket ecu required for that car which is automatically illegal in my state. So it's an attractive option IMO, and if you have the cash.

Tweety · Post by **Tweety** » Fri Aug 03, 2012 12:03 pm

WELL wow!!!!! Tweety hasnt been started for about 10 days or so. Finished fitting the manifold with rubber/alloy gasket. choke, started it up (it wouldnt run last time without choke all the time. And it started easily and so well I took the choke off after one minute and it idled....900rpm...spot on.

Am I happy or what? The mixture screws were able to screw down to where they should be (they were screwed out about 6 turns). I just shut it down to allow a bit of heat on the gaskets and let it dry a bit more before I go for a run.

Adrenalin......that's what I'm talkin' about. Thankyou to all of your support forumites.

Think I'll make a short video with that boost guage going up and up.... stay tuned.

YouTube · Post by **El_Freddo** » Fri Aug 03, 2012 7:15 pm

So what's the boost pressure worth now?

Cheers

Bennie

Tweety · Post by **Tweety** » Fri Aug 03, 2012 8:32 pm

4psi max.

I'm a little reserved on the boost indication. You would think acceleration would be roughly the same from 0 to -10...where there is just vacuum. But when I take off even with say -3 or -4 it wants to move...really move in comparison to non SC.

I'm going to first take it to an igntion place near VWPC to get all the ignition checked out before I take it around the corner to the dyno. I've made a lot of changes and mostly didnt know what I was doing really to the ignition...so am going to get peace of mind with it.

Then the dyno and I'm certain we will be reverting to 150-160 main jets.

Then it should boogie. And I dont want to touch it for a while...

Then I have to buy two VW mesh alternator belt screens and join them to shield the ribbed belt and the alt for RWC reasons (required for trikes) then engineer time. Then prepared for around Oz trip. eg male a shelf for Rosy the mini Foxy and fill van fridge with Cougars.

Tweety · Post by **Tweety** » Sun Aug 05, 2012 7:26 pm

Time for a review.

Specifications

Engine: Subaru ea81 Brat/Brumby
Trans VW Type 3 full 3 spd auto
Wheels/tyres 295/50r15
Trike Panther Australia Wildcat 2008
Roof Custom designed by owner built by McKernon’s Euroa Vic Australia

Supercharger Toyota SC12. Set up as a draw thru

Pulley’s Crank- 130mm, SC- 120mm (standard SC12 pulley clutch discarded and fixed- cannot have clutched pulley on draw thru system

Boost Sought 4-6psi. This level of boost enables you to not go to the bother of internal engine upgrades required for beyond 8psi.

1. Engine capacity - 1.781cc ea81
2. Maximum engine speed you will be using. 5000rpm 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 5psi

SUPERCHARGER CALCULATIONS

The calculations are:
1/ FIRST CALCULATION (Engine Litres/min @ 0 Psi )
Multiply engine capacity (in litres) times maximum engine Rpm. Ea81 1.781x5000= 8550 litres/minute. Divide this figure by two as engine only fills every second stroke.
8550/2 = 4275 l/min.
This is the engines air requirements in litres/minute at 0 Psi boost.
2/ SECOND CALCULATION (boost ratio)
Add the boost pressure desired (5 Psi) for the engine to 14.7 Psi (atmospheric pressure).
(5 psi boost desired +14.7 =19.7 psi)
Divide this answer by 14.7 and this gives the boost pressure ratio. 19.7/14.7=1.34 This is the boost pressure ratio above atmospheric pressure.

THIRD CALCULATION (Actual air requirements @ desired boost)
Multiply the boost ratio (1.34 by the litres/minute obtained for 0 Psi (4275)and you get the actual air requirements in Litres/min for the engine at that boost
5728 L/min ea81 for 5psi boost.
So now we have the following:
- Engine litres/min @ zero psi is 4275
- Boost ratio is 1.34
- Actual air requirements @ desired boost is 5728 l/min for 5psi
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 5728 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.
5728/1.2 = 4773 rpm supercharger rotor speed.
CALCULATION (Pulley size ratio)
Divide the rotor Rpm 4773 by maximum desired engine rpm 5000 to get the drive ratio of the pulleys. (ea81 4773/5000 rpm @ 5psi = .95) near enough to 1:1. I sort out a 135mm circumference 5 ribbed pulley to mate it to the standard Alt crank pulley (120MM).

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) FOR 1:1. 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. But there is a drop due to volume efficiency.

So my SC pulley is 120mm and crank 135mm. 1:1.1 ratio. Eventually I achieved 5 psi on this set up. There is one consideration not mentioned- volume efficiency. Most engines lose some efficiency due to their designs. The ea81 has 79% VE. So the extra gearing of the slightly overdriven pulley sizes evens this out. If you want more boost then a 103mm fixed and clutch pulleys are available from pulley Brothers. http://www.pulleybros.com.au/

The dyno graph tells a clear story. The green lines indicate non supercharged engine and red lines with the SC12. Power up at the wheels from 59hp to 82 (32%). Torque an increase of 30%.
Power at the flywheel was around 100hp. But this figure was interrupted by an air leak in my custom manifold. So new dyno figures will be edited in here in a week or so. I don’t expect any improvement.

Information to be updated and edited when required. Tony

Tweety · Post by **Tweety** » Fri Aug 10, 2012 9:52 pm

Left Strathbogie at 7am this morning. Boy it was cold. Would ahve to be snowing somewhere close. Rained all the way to Yarra Glen. In such medium rain I get nearly as drenched as a triker without roof and screen. Butr my torso is always dry and my feet and legs not only dry but warm from the radiator ahead of them. I stopped at Castella even in the rain and waited till the thermo fans went on after temperature crept up to 86 degrees. Then I had a wamr and continued on.

I had an appojntment at Performance Ignition in Nunawading. The plan was to check out Tweety's ignition system as I'd modified it a lot over the months and the last dyno showed up some problems. Well the palce was 4 workers short and the guy was reluctant to do any work at all. I protested strongly on the basis that a dyno was booked in at VW performance Centre later this morning and I'd ridden from Bogie through a freezer. He relented and proceded to take apart the dizzy.

Regardless that I was told 15 months ago the dizzy was unused Peter told me it is a refurbished dizzy and its vacuum was a whopping 32 degrees, way in excess of what I required with a supercharger. The unit was recalibrated to 24 degrees and the vacuum spring replaced with a stronger one to make the advance slower. The oil hole that allows lubricant to enter the shaft was enlarged. The dizzy was cleaned and reassembled. I rode away and it pinged like hell. But I was alte for the VW centre so I pressed on.

Daniel had recently done a dyno and we had a manifold leak resulting in main jets of 225 being inserted.

The good news is that this second dyno resulted in main jets of 180, much much leaner. Daniel explained that leaning it more would cause it to be too lean on boost- something to avoid. HP readings were the same as previous 82hp. So at this point there were no air leaks and the engine was tuned well and idled nicely. Then we had a few issues to resolve.

The carbie was tilted down towards the front of the trike. It should be level
- can be fixed with a new adapter plate

The carbie is level when sighting it from the rear of the trike whereas a slight tilt so the airbox end of the carbie is a little higher is more ideal.
- if the new adapter plate is milled a few mm's it will fix this

Daniel found a very minor airleak at the silicone tube of the manifold sleeve (drat!)
-best to cut off the oval shaped pipes and weld new totally round ones on allowing clamps to seal perfectly

We had an intermittant starting problem The engine would turn over but 3 out of 4 times wouldnt start.
- this was why I wanted the ignition place to do what I booked the trike in for- an ignition check. Daniel determined that tapping the dizzy helped start the engine. He found a hairline crack in the module and had another delivered. However it turned out not to be the starting problem. Holding the coil lead to ground as I cranked the engine showed that spark was intermittant. Once started it ran perfectly.

So that issue needs an auto elec or igntion expert to look at. Regardless, I rode it home and it ran beautifully. My only hiccup I lost high neam at Glenburn. It rained most of the way. I enjoyed the power up the hills especially. Still showing 5psi on the boost but it seems more economical if the guage is anything to go by and the less smelly black exhaust. Time will tell.

So still some work to do to finish off this project but much progress today.

steptoe · Post by **steptoe** » Sat Aug 11, 2012 9:00 am

You gotta love the tuning specialists eh! I took a beast for dizzy curve taming - nothing more and came away with an invoice for a new priced dirty HT lead (this is where those mismatching leads come from !) COMPRESSION TOO HIGH FOR ROAD USE scratched across invoice, I got home to find the points dwell was not factory, timing set at about 8* when supposed to be 2* +/- 2 and I was running 230 cranking psi - 2* was enough. Worked out the gooses confused timing markings between six and V8 timing case marks indicated with numbers !! ( i think) . I reset dwell to 36 * , timing to 2*, tweaked dizzy spring with pointy nose pliers - she ran real sweet after. Not been to a tune shop since 1985

Tweety · Post by **Tweety** » Sun Aug 12, 2012 6:10 pm

Yeh, similar here Steptoe, the guy appanrently tuned it to the wrong marks.

Anyway, the situation now is this: the supercharger produces 4psi with the rare 5psi showing on the guage. I've lost any economy gain I had when going from the VW 1916cc engine to the ea81. Shame, I enjoyed the extra 100kms to a tank (50 litres). Dual fuel is still a thought. I need to investigate this- even if I have to use a different carbie to a single throat. 13-14 L/100kms is a bit hard to swallow especially when we want to ride 17,000 kms around Oz towing our van which will drink more.

We rode to Ballarat to see our new pup (mini foxy) through rain and freezing cold temp. The only issues with the engine was a very small leak (again) in the manifold area me thinks the silicone sleeve. The two halves of the tube it covers is oval shaped- not a good seal. easy fixed and fixed it will be.

The up side is the performance. Up hills it flies. Easily exceeding my expectations and this is with 1 or 2psi on a light throttle. As a comparison going up the Euroa to Strathbogie mountain Tweety with the VW engine would slow down to 60kph, into second for 300 metres before enough speed to go into top. The ea81 unblown would slow to 80kph into second also but enough revving ability to maintain 80. With the blower 105kph easily reached and maintained top gear likley more if full throttle used. You soon realsie that you rarely need full throttle. This is a big difference. Also overtaking is done in a blink of an eye - a safety feature.

The engine is noisier understandably. A few options. One is ear plugs, ipods whatever. The other is some soundproofing under the body of the trike fixed to the fiberglass. Its a gitsy sound but a bit of a drone after some time. When we got home and its idled I touched the SC and it wasnt hot. I was udner the belief it would be too hot to touch. So I'm thinking of making a jacket for it out of fireproof material, something I could slip over it and take off easily. However I'd assume this is going against logic as the sC needs to emit heat so I might go the other way with soundproofing.