Supercharged ea81 SC12

[tweety]

When my Panther had its VW 1916 engine I didn’t consider a supercharger. Maybe if I did and had read “Joel’s” superbly documented thread at http://forums.aussieveedubbers.com/viewtopic.php?tid=65678&page=5 I might never hav considered superchargers

Joel mounted a Toyota SC12 supercharger to his 1776cc aircooled VW engine with fabulous results. The larger SC14 (read longer by 50mm) doesn’t fit in the engine bay as the doghouse gets in the way. Regardless the SC12 fits well.

For the novice (as I was 8 weeks ago) let me explain in laymen terms, what this is all about. Turbo chargers run on exhaust gasses, superchargers run off the crank pulley. Superchargers boost is calculated by a formula…I’ve included the formula later. Such formula depends on pulley sizes, the cc of the engine, the size of the SC etc. All basic stuff. Turbos and SC’s have positives and negatives. The supercharger has its boost virtually throughout its rev range. Perfect for towing and enhancing the engines torque, indeed lowering its max torque point a few hundred revs.

Superchargers can be expensive. However many people are buying the SC12 or SC14 for less than $400. Total package though is still less than $1500. For around 30% increase in torque and power (say 6-7 psi boost) it is the cheapest bang for buck around. You can buy a sprintex supercharger that have even managed to find their way into new Harleys. These are “twin screw” superchargers meaning the air is compressed internally in the unit unlike the SC12 Toyota units that are called “Roots type” that pressurise the air on the outside of the blower. These are Australian Sc’s and are very efficient. There are centrifugal SC’s also. But I wasn’t prepared to fork out many thousands of dollars on this project.

Electric superchargers are on ebay and other places. They, in my view are a waste of time and money.

There are two methods in connecting up a SC. First is the method that the blower was originally designed- to compress air only through a carbie and into the engine. This has a few issues with the home built conversion. The carbie has to be built/rebuilt to withstand compressed air for example. This is called “blow through”. But there is a simpler set up.

“Draw through” means the carbie works in its conventional manner to inject an air/fuel mixture into the blower. The blower compresses the mixture before it is ingested into the intake. No carbie mods are required though there are good and not so good carbies to select from for this purpose. It is commonly known that SU’s are good as are side draught webers and Dell’orto’s. Some are more efficient than others so there is some homework there to do.

So onto Tweety, the Panther trike (Oz). I wont go into why I selected the ea81 Brumby/brat OHV engine in the first place in detail except to say that I wanted simplicity in that I wanted to service and maintain my trike myself. I know my limitations and DOHC’s and wiring looms a ,mile long scared me off. Having said that I also carried out modifications on the standard Panther tow bar to make it run the full length of the trike for it to tow a small caravan weighing some 450kgms wet. I didn’t count on the automatic zapping 15hp out of the engine though. On a dyno the engine, correctly recoed 60,000kms earlier by a Subaru mechanic produced a healthy 75hp. It tows the van well but hills see it die a little too much. A 4 speed manual would have more usable power.

So I decided to install an SC12. I purchased one and also purchased a Lynx twin carb manifold suitable for a Datsun 1600-2 litre engine. I cut the manifold in two parts. This was suitable for my needs because the ports, as they meet with the blowers intake, are close together as are the square SC intakes. I made up a small adapter plate. Then I purchased a Dellorto 40mm DHLA carbie fully refurbished for $210 on ebay with a spare carbie for $60.

I needed to mount the SC and did so between the alternator and the engine intake by utilising the cast iron mount.. I made a manifold from two 75mm steel pipes welded together sideways, added a blow off valve and I thought this was going to be easy. It wasn’t. I would recommend anyone doing this set up to make two separate mounts one on the SC exit and the other on the engines manifold intake both with 75mm pipes and connect them with a short length of 75mm silicone tube. This allows for imperfections in the joining of them. If the SC is hard mounted like mine you wont need a top mount. If you use the silicone tube then you’ll need a top mount which isn’t hard to make.

When making up the manifolds/adapter plates I finished the joins both externally and internally with Devcon plastic steel. A more common material is JB weld. This epoxy can line the inside with little chance of breaking off, is sandable etc.

There is usually a pulley on the SC12 that has an electric clutch. This is not suitable for a draw through set up. You need the blower operating all the time with draw through. So I got my engineer to fix it with 3 bolts through it. At the same time he fixed a 5 ribbed pulley to the crank pulley. Then I purchased a Ford tensioner pulley and mount. I used a 5 ribbed belt 5pk-0965 which is a common size.

The specs of the set up are: cranks pulley 135mm, SC pulley 120mm. Calculated boost around 6-8psi.

Below is a calculation using my Ea81 engine. Simply calculate your own by replacing my figures with yours.

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.

To choose a setup you need to know :-

1. Engine capacity 1.8

2. Maximum engine speed you will be using. 5500rpm

3. Boost level desired 6-8 psi

 

I am setting out the calcs needed for a 1800cc engine in the steps below.

 

FIRST CALCULATION (Engine Litres/min @ 0 Psi )

Multiply engine capacity (in litres) times maximum engine Rpm. E.g. 1.8 litres x 5500 rpm = 9900 litres/minute. Divide this figure by two as engine only fills every second stroke.

9900/2 = 4950 litres/min.

This is the engines air requirements in litres/minute at 0 Psi boost.

 

SECOND CALCULATION (boost ratio)

Add the boost pressure desired (8 Psi) for the engine to 14.7 Psi (atmospheric pressure).

(8 psi boost desired +14.7 =22.7 psi)

Divide this answer by 14.7 and this gives the boost pressure ratio.

(22.7/14.7=1.544)

This is the boost pressure ratio above atmospheric pressure.

THIRD CALCULATION (Actual air requirements @ desired boost)

Multiply the boost ratio by the litres/minute obtained for 0 Psi and you get the actual air requirements in Litres/min for the engine at that boost. In our example this is 4950 litres/min X 1.544 = 7642.8 litres/min for 8Psi boost.

To decide on the correct size of supercharger you need to know :-

1. The swept volume per revolution of the supercharger. ( SC12- 1.2 L/rev)

2. The maximum continuous safe operating speed for the supercharger. (Toyota SC12 11000 rpm??)

3. The maximum pressure that can be safely produced by the supercharger continuously. (Eaton M62 12 psi, SC14 10-12Psi)

 

CALCULATION (Supercharger rotor speed)

Divide the desired air flow (7643 L/min) by the swept volume of the supercharger (SC12 from the is 1.2 litres per revolution). This will tell you the maximum speed the supercharger rotors must be run at to produce the volume required.

7643/1.2 litres = 6369 rpm for the SC12 well within its capabilities.

 

CALCULATION (Pulley size ratio)

Divide the rotor Rpm by maximum desired engine rpm to get the drive ratio of the pulleys. For an SC12 on a 1800cc @ 8psi boost the desired supercharger pulley ratio is

6369 /5500 rpm = say 1.1:1

 

My Crank pulley is 135mm diameter and SC pulley is 120mm. About 1.1:1 =spot on.

Ignition and Fuel.

Commonly and especially with aircooled engines the ignition should be retarded or the advanced limited. As you are forcing air into the combustion chamber more fuel is needed to balance the mix. Hence larger jets. In both cases a dyno should sort this out. Be warned however that a rich or lean mixture can cause harm to your internals.

Intercoolers. Read up on them. They are not however suitable for draw through set ups.

 

Test ride.

Tweety’s Dellorto was rich and the engine bogged down a lot. Eventually I feathered the throttle to enable him to pick up speed. Then going up a small hill I let him kickdown from 3rd to 2nd and the front wheel lifted. The trike has more kick in the back and I’m impressed. Tuning will result in a better response.

Supercharging is addictive and some say eventually I’ll want more boost. Trouble is when you go over about 6psi reliability becomes an issue. The SC12 in my case is spinning at around half its capability. I am happy enough and don’t want a screamer.

 

Lining up the belt correctly is critical.

 

 

Finally, tuning is critical. get it right sooner than later.

Edited June 27, 2012 by tweety

[Ibreakstuff]

Wow, impressive. Just keep it below 88 mph there doc, we don't need anyone going back to the future.

 

[TheLoyale]

Just wow!

[iceageg]

Good write-up and a big congratulations on getting done what you wanted, the way you wanted it set up. It turned out great. For others looking to do something similar here are a couple of other items to include in your design checklist.

 

These equations are good but there are a few other factors that can impact the actual boost your engine gets. One is the efficiency of the engine and the other is the ductwork the boosted air travels through to get to the throttle. It is easy to loose a couple of pounds of boost and tons of velocity to these factors by the time it actually enters the cylinders.

 

One more factor to keep in mind is where you place the belt tensioner/idler. The tensioner should always be placed on the slack side of the belt, closer to the supercharger pulley than the drive pulley. Whenever possible the tensioner should squeeze the belt inward (creating more wrap on the pulley). This is done to ensure the belt does not slip causing premature belt failure and erratic boost delivery.

[BratRod]

That thing is wicked

[LPGsuperchargedBrumby]

nice workmanship

 

just one thing about your setup....if you run a SC12 or SC14 in draw through from a carb the petrol can cause the teflon coating on the supercharger lobes to come off after a few thousand miles....which causes you problems

 

i ran my old supercharged EA81 on LPG so i didn't have this problem when i was running draw through

however i was shown the results of this by a VW nut friend of mine that had two SC12 failure's from this when i was building my supercharged setup...not pretty

 

lol your blow off valve might want to be turned 180 deg so its not blowing fuel air mix over your coil and under your seat

Edited July 1, 2012 by LPGsuperchargedBrumby

[tweety]

Thanks for the good advice guys.

 

The BOV now ducted to the cold air intake as it was designed to be.

 

The tensioner- well there isnt many options there I'm afraid. it is on the slack side but closer to the crank pulley. havent had slipping issues though. And it takes a common belt size.

 

update

 

I've allowed for the gasket goo to set.

 

At least I know there are no leaks there now on that custom manifold.

 

Fiddled with jets a bit ended up with 145 mains and 6 degrees timing close to standard timing. But there is still just a little hesitation and as I got rid of most of it then it has to be a tuning issue. Wont know how ridable it will be until the rain stops.

 

Click on the next pic for a video

 

 

 

And yet again while fiddling with timing the engine backfired and that BOV worked so well.

 

 

As for teflon being removed in a draw thru set up. I've had a number of reports here in Oz that that isnt happening. maybe the octane is different?? also the mild level of boost made possible with the Sc running only half its ability eg 6500 rpm might be a factor for longatibity. Here's hoping.

 

 

and here is the trailer I tow.

 

[tweety]

Went for anther ride today. achieved 4psi boost on the guage. gettign tune next Tuesday. jets arent right.

[tweety]

Today was more sweet than bitter but it could have easily turned horrible.

 

Took off at 6:30am bound for Croydon to my friends at VW performance Centre. Got to yea and broke down at the servo when Tweety's engine wouldn't restart.

 

Turned out much later that there was a lot of condensation in the electronic dizzy. Not the first time!

 

Eventually restarted and the engine broke a supercharger belt at Glenburn. Inspection revealed the belt had a tendency to move towards the engine. Later Daniel from VWPC found it was out iof alignment by about 3mm resulting in one of the 5 ribs on the belt to fray, break then the rest of the belt followed.

 

Luckily I had a spare and pushed on from Yea to Ringwood East where the second belt snapped. I heard it go. But pushed on regardless and found that indeed the engine can maintain power without the belt...no boost of course.

 

So Daniel took about 2 hours to make a spacer between the crank pulley and the SC ribbed pulley, plug weld it together etc. Then it was dyno time.

 

I had had 145's as a main jets in the 40 DHLA Dellorto,. In the end we had 225's so you can imagine how lean it was running. Air jets were matched. Accelerator "pump" jets had to go to greater sizes too. Initial runs were disappointing. Last years HP maximum was 60 hp at the wheels. These runs were 58. I asked Daniel to check the throttle. Yep...less that half effective throttle when squeezed tight- my fault. We spent some time remaking a better throttle set up with more throw and a better link.

 

82.2 hp at the wheels compared to 59.6 last year. a good jump of 32% in hp. I began to raise a smile. At only 5 psi boost.

 

Torque last year was 440lb this year 570. another substantial increase. (Tractive not actual torque) 30% increase there.

 

Here is the graph. The green is last years results after the weber carb was installed. Todays is in red. Power is the humped curve, torque the flatter lines.

 

 

That was at the wheels. last year the flywheel HP was 75. This year....well we got it way up toward 98 then we had an issue. The engine firstly wouldnt idle under 2500 rpm. Then it wouldnt start. The condensation was blown out with air. Then Daniel found a leak between the custom manifold and the base adapter plate. I recognised that spot. The gasket and hence the gasket goo area was less than 3mm wide between the intake neck and the mounting stud.

 

So we packed up our box of tricks and decided I'd remake the manifold. Daniel supplied me with some 75mm pipe and a leice of 75mm silicome tube.

 

Homewood bound and the difference was- well extraordinary particularly acceleration between 80-110 kph. Truly quick by previous standards. Tackling hills is a breeze where previously I'd drop speed to say 80kph or even drop down to second the trike maintains 100 kph effortlessly. When the trike does hit a slower steeper incline and drop down to second the front of the trike lifts. Not off the ground at that speed say 60kph but you do get that sensation of the machine sitting on its haunches- nice.

 

Boost max indicated was 5psi. I think I'll be happy with that. I wont rule out at a later time changing the SC pulley to a slightly smaller one to get a bit more boost but I'll leave it alone for some time yet.

 

Now to rebuild that manifold and get the manifold between the Sc and the carbie shortened to make way for a wider air box

[LPGsuperchargedBrumby]

a bit of boost on that engine make a fair bit of difference....thinking back to how the power came on in my old blown motor the power increase was most noticeable at about the same speeds your talking about, between 50 and 100k.

 

one thing i always found a bit of a giggle was being able to light up all 4 wheels while crossed up on gravel whenever i wanted...it defiantly was needed on the drive home from work sometimes lol.

 

if you up the boost watch real carefully for detonation above about 7 psi...adding water injection will let you go to about 9 or 10 pound before you hit det' issues

 

cheers for putting the dyno chart up, i wish i could have dyno'd my ute, it would have been nice to know what it was putting out

[tweety]

They say Supercharging is addictive.

 

So am going to take it easy on upping the boost. think I might see if I'm happy to live with this 5psi. Also the trike only weighs 600kgms so when the engine is under laod it isnt under that much load. Towing my caravan will bring out the best in it, then I'll see if I need more boost. But I dont think so and as you say detonation....dont want that- more trouble eh.

[el_freddo]

and as you say detonation....dont want that- more trouble eh.

 

Not on the golden lap that's for sure!

 

Cheers

 

Bennie

[tweety]

Its taken a while but am ready to install the new improved manifold each side of the SC12.

 

This is a pic of the original set up. You can see the grey airbox and how thin it had to be due to the roof frame coming very close to it as the roof was tilted back. The black manifold on the left mounts above the intake. It had an adapter/spacer alloy made by redline under it that had very littel meat to create a good seal- hence a leak.

 

 

This is the new set up. I used the spare lynx manifold half to get it shortened.. This allows for the new airbox. And I'll have one centimetres spare. The new manifold to the intake is made out of 4x2" steel tube for the top onto 75mm steel tube under to to the intake the latter being halved for the silicone tube.

 

Look close enough you might see the Devcon plastic steel lining insdie the lower mount to allow for smoothness for the fuel mix. Good stuff but not cheap.

 

 

Couple a days and she'll be running again hoping with a nice idle with no leaks.

[tweety]

Mounting a Sc is the hard part. This is what I've read on many web sites.

 

It is easier with the trike, more room. But there is a procedure I now acknowledge as an easier method of carrying out the mounting of the unit rather than the ways in which I carried it out. It may or may not be relevant to a Subaru car but you might benefit by this example.

 

My first lesson was that there is no real advantage in making a (permanent) hard manifold mount between the SC and the intake. A 50mm silicone sleeve between the upper and lower mounts is a good idea as it allows for small adjustments with the SC to take place.

 

This is my recommendation.

 

Purchase a 5 ribbed belt 5pr-0965, a common size. These belts go up and down in size by 10mm which is quite a lot so you have to have some accuracy when doing this mounting procedure.

 

Finalise your pulley selection and fit it to the SC. I used the standard clutched ribbed pulley and removed the clutch centre and got my engineer to use 3 bolts to bolt it solid. With the crank standard pully at 150mm it works out at 6-8 psi. I've achieved 5psi as ther eis some loss with volume efficiency and I had air leaks so I might get more boost later. Not that I'm disappointed with over 30% more pwer and torque.

 

I would advise that if you are fitting a SC12 or 14 to your engine then its advisable to fit it as close to the intake as possible. If it is to be located between the alternator (that has the cast iron mount) and the intake hole the first thing to do is to locate the SC into its near exact position with the belt in situ tight as possible but with no adjusting tensioner fitted as yet. Take some time with a flat edge to get the belt lined up. Use whatever means to keep the SC in this position. Then fabricate a single solid mount from the intake to the SC. I would do this with 5mm steel lower mounting plate mounted directly onto the intake. make sure you tap that hole with a 12mm tap and insert a 12mm grub screw into the hole to prevent future problems with radiator fluid leaks. Seek out some 60mm or 50mm steel tube weldable thickness. You will find the Sc outlet is closer to the front of the engine than the intake hole. So your manifold will be on an angle. This is relevant to mention.

You'll need a blow off valve. When your engine backfires you need this to operate to prevent breaking stuff. I used a turbo BOV without connecting up the top vacuum hose. Worked a treat a few times when I had tuning issues. You will need to plumb this back to an air intake area. The mount that the BOV comes with is alloy. I got my engineer to turn a steel one up on a lathe. This will need to be fixed to the lower or upper manifold peices after seperation. One issue is where bolts for both ends are located. Use 75mm steel tube like I have and you have plenty of cutting and bending of the tube to ensure access to the bolt heads are gained. Smaller tube like 60mm or even 50mm allows for much more access. Nothing worse than trying to fit a nut to a stud in a crammed area. With that angle of the manifold the rear lower stud on the SC poses the most problems. Larger tube has the welds close to the bolt heads. All sorts of time wasting can be had here hence my suggestion to go smaller tube than 75mm.

 

So you have the SC secure with your manifold and nothing else at the moment and your pulleys are lined up within say 1-2mm. This manifold will later be cut in two peices. Now make up a lower mount under the SC. I used 10mm x 20mm steel flat. There are plenty of mounting points on the ea81. Thread through the SC mounting holes a long bolt 3/8th with nuts between the lugs and one at the end. With the "flat" bolted to the engines manifold and at the front you can weld the last nut on the bolt to the flat. Do the same with a nut up near the bolt head- that is connected to the cast mount for the alternator. I built a small steel frame here for the tensioner. The large bolt can be unscrewed when you want to take the SC off.

 

Make up an overhead mount. This can best be made with 20mm square steel tube running from a mounting hole near the temp sender on the ea81 manifold up to the two top mounts on the SC. I had a nice bend in the tube.

 

Unbolt the new manifold between the SC and the intake. Cut the tube with a 5mm slice out of the centre. At this time it is convenient to use Devcon plastic steel inside the peices to make it smooth especially in nooks and crannies where fuel can pool or minimalise friction. It is expensive but it is permanent and proven for use inside manifolds. place clamps on and the silicone sleeve. The sleeve needs to be short enough to slip down covering the lower mount. Finalise the assembly.

 

You will notice the SC is on an angle. It cant be mounted vertical because the alternator wont allow it. So any side draft carbie has to have a mount that allows that carbie to be flat. This is where you need a carbie manifold that allows for that angle. A cut down one, a newly fabricated one of as I ended up doning - a cut down half section of a lynx twin carb manifold. Make sure you get the vacuum holes tapped. Make up a adapater plate to the SC 5mm or more thick.

 

WARNING!! These superchargers have standard mounting studs for each manifold. The holes for these studs go right through to the teflon coated lobes. You must be careful if replacing these studs with bolts or if the studs screw further in than they are suppose to. The screw ends can easily hit the lobes and cause damage. It is said the teflon coating isnt that critical eg scratches and scores wont necessarily cause performance issues. But its nice to avoid it. I had a few stripped threads here. I drilled them out and tapped them. To do this make sure you have an oily rag inside the Sc to catch filings. Take care, the lobes can squash fingers and edges can cut them too as tolerances are fine and edges sharp.

 

You now can mount your carbie. I used a 40dhla Dell'orto. Seems an ok choice. SU's are a good choice too apparently. Design your airbox, cold air intake advised. You'll need a new throttle linkage. I sought out a EA Ford Falcon tensioner smooth pulley. This should be mounted to the "slack side" of the belt. eg opposite to the pulling side from the crank to the SC pulley - being the left side nearest the dizzy. Your belt at this time should be snug enough to jsut get it off the pulley if required. Then mount the tensioner so its pulley it all the way out. I say this because it isnt apparent that even though the belt is snug it will stretch somewhat when under tension. Tension it up quite tightly. When you first start your engine keep a close eye on the belt. If there is any minor fraying on one side or it starts to mount the ends you can ruin a belt quickly at 40 bucks a pop.

 

Make sure the SC has its 3 small tubes in place to allow for air pressure equalisation between the chambers, oil is replaced preferably with SC oil. I used GMH oil and you'll need two 95mm bottles at $49 each. Some say transmission oil is ok as its only gears to lubricate but I like peace of mind. Prior to putting in the oil I took off that back plate, cleaned it all inside and a little silicone on the case join. The rubber "O" ring is about 20 years old or more so a little help to keep the seal wont hurt.

 

Install a boost guage. I chose a digital one form ebay for $18. Nice blue digits!

 

TUNE. Bear in mind the issues I had with air leaks. If your manifolds leak air then your jetting when tuning will end up rich and waste a dyno. So the real benefit with the above procedure is fitting the one peice manifold between the SC and the intake with the SC in the location it will end up with the pulley's lined up. Later that manifold will be cut in two to allow for a sleeve to join them.

 

If I had known this before I started I would have save many days and a lot of work.

[tweety]

Ok, have almost got it all sorted now.

 

I had serious air leaks between my custom made manifolds. And after much trouble have found that the SC exits are not fully flat...why? Because as standard they dont need to be!!

 

Standard manifolds in Toyota cars where these sC12 and SC14 SC's are fitted appear to have tin like material which would flex with the base. Its about 1mm but enough to cause and issue when using 5 or 8mm plate as a manifold face. I originally used 3mm and that warps when welding takes place.

 

I kept the 3mm manifold face but had it linished and used a far better gasket than paper. I picked up some rubber gasket with a strip of alloy in it. About 2mm thick it is THE stuff to use in this application.

 

A smear of gasket goo and assembly took place. Now I have an idle to die for. A test run ahve me 5psi and good idle. But it now runs rich- back tot he dyno machine. Update to come.

 

The rubber gasket. Superb stuff.

 

 

The now two peice custom manifold. Top ring is for the blow off valve. Silicone sleeve and clamps compelte the assembly. A top mount seen on the left hand side now braces the top of the SC. Note the tensioner is on the "slack" side of the ribbed belt. I plan to purchase two VW generator mesh shields to make the belts a safe place for fingers. Besides they are law here.

 

 

A test run and I'm reminded how effective this Supercharger is. It is more noticable at low revs. The throttle is more touchy and the front wheel gives me the sensation of lifting. Then there is a progressive acceleration at full throttle that is so much better than non sC. But ti is the speedo diference that is where the tell tale is. Adn the trike around corners under certain revs seems to sit on its haunches, more on the back wheel as you power on- a sensation that increases my testosterone...lol . Easily reaching 130kph (private property ok police!! if you are reading) before I backed off. Am not interested in what it does top speed. This trike is a cruiser and always will be. Dont want my sunroof to reach New Zealand.

 

There is a slight increase in noise, not loud but a course sound with the added sC spinning away. I'm happy, and happier when the dyno results come out with it jetted correctly this time.

[tweety]

Used 3mm HITRILE rubber for all manifold gaskets and eliminated all air leaks.

Great stuff resistant to gas.

 

Can now concentrate of cosmetics. Two vW Scat belt guards protect fingers- a legal requirement in Victoria.

 

 

There are two belts now and too wide for a single guard.

 

 

3 wing nuts with welded bolts make detachement easy and quick.

 

Water injection is now being planned. Spinning at only 5500 rpm the supercharger doesnt get very hot. But water will seal it more, add a little more boost, eliminate detonation (although I've eliminated it now altogether but it will allow me to advance the timing) etc

[Mykeys Toy]

Very cool project.

[tweety]

Thanks Mykeys Toy

 

I've had one suggestion that the airbox is too small and would/could contribute to the rich running of the engine and affect economy. So I'll seek out another large one the same as the original one I cut down (but wont be cut down this time as I have more room since shortening the carbie manifold)

 

I wan tit totally finished with water injection and reliable before I get another dyno

 

LPGsuperchargedbrumby infomed us of risk of detonation above 7psi and water injection will take it to 10psi before det takes hold. Everytime I take it for a run the power and torque impresses me so much. So I wont be changing the pulleys at all now. If I get 1-2 psi with water injection then that will be a bonus, cooler running in the summer and when towing.

 

The whole project was, in the end, spot on regarding my dreams. The install of the ea81 was only disappointing in respect to the auto zapping 15hp from the rear wheels- now that has not only fixed that it has transformed the trike in every way. And its simple to work on.

 

small airbox, intake on the right hand side

 

 

the larger one cut down to make way for the roof frame at the time

 

 

You cans see the airflow would be restricted here.

 

 

 

 

 

Elfreddo has ridden Tweety. will be interested one day when he has another ride and feel the boost.

Edited August 27, 2012 by tweety

[tweety]

Nitrile rubber 3mm thick was superb and highly recommended to seal manifolds that dont go above 90 degrees C.

 

Have had delays but have compiled most of the parts for water injection.

 

For those that have followed this project and dont know a alot about superchargers (and I didnt 6 months ago) when the engine gets boost form the blower detonation inside the combustion chambers can easily occur. A few measures can be taken to eliminate this.

 

Retard the ignition. The ea81 Brat engine runs at about 8 degrees advance at idle and often runs to 32 degrees at full advance, The blown engine doesnt need this amount of advance so I had my electronic distributor recalibrated to alow it to run to 24 degrees at full advance. After a few days running it still detonated (pinged) up hills So I retarded the timing at idle from 8 degrees to 2 degrees and it vanished. However this meant I was not running the engine at its optimum power point.

 

Water injection. Its been around since Adam was a boy. The concept is to inject water as a vapour into the combustion chamber to stop detonation so it allows you to run the timing at 8 degrees and not have pinging on boost. It will give more lower and 1 or 2 psi extra is common.

 

How to install it? There are kit available. Autospeed have a DIY system that you make up using a 12volt/220volt inverter. There are some very good ideas on their web site. http://autospeed.com/cms/title_Water-Injection/A_107970/article.html .

I decided to not go the inverter route and prchase a 220psi pump from Snow performance. They were really quick in replying to my emails too. http://www.snowperformance.net/ good service. Their 150 psi pump is no longer available. They have kits also. The pump is quiet in operation.

 

So Tweety has a draw through system with a SC12 Toyota supercharger. Mening gas and air goes through the blower to the engine. There are many debates on the www about the best place to locate an injection nozzle/s for water injections. So I wont bore you with the arguements. I've decided to palce it between the carbie and the blower. My reasons? 1/ even though I'm running only 5 psi the blower doesnt get very warm. adding water vapour to the mix will have a cooling effect on the lobes as well as a sealing effect that could add 1 or 2 psi to the boost. 2/ placing it after the carbie wont casue rusting issues to components in the carbie 3/ That manifold has vacuum, the injector wont be battling against boost.

 

The components.

 

Nozzle/s. Any smaller than 0.3mm and atomisation wont happen. Neither will it happen with less than about 80psi. Snow also have very small nozzles. I ordered their smallest nozzle that if running continuously will empty the small tank in 25 minutes. So with this revellation only one nozzle is required. Snow nozzles come with a small filter insode them so you want easy access to it for cleaning.

 

Water tank

 

On tweety weight has been creeping up with the roof mod and supercharger and radiator etc. So I'm not wanting to carry the normal quantity of water like you would a car say 1.5 gallons. So I found a 2.5 litre 0.6 US gallon windscreen washer tank in black which will help with algae. Water injection will only be used on boost. I'm hoping I will use one tank of water to one tank of gas. When towing our trailer (caravan) it will be on boost more often.

 

 

Filter

 

I've taken Autospeeds advice and purchased a caravan fridge filter. They come with quick release hose ends and last 1500 gallons. great idea.

 

Pump

 

220 psi Snow performance pump. A relay is recommended.

 

 

Tubing

 

Common water injection line

 

Pressure switch

 

Many pressure switches on the market come on at 5, 10 or 15psi boost. I found one in Oz that turns on at 0.5 psi. To be hooked up to the pump earth wire.

 

Check valve.

 

This valve before the nozzle stops the vacuum sucking water when the pump isnt operating.

 

That's it. I'd also recommend reading up on the web for your application. I'm hoping to install it in the next week or so.

[tweety]

Water injection.

 

It isnt easy finding a simple boost switch unless you want one to come on at 5 or 10 psi. I wanted one to come on at 0.5 psi to activate the pump.

 

Found one for $43 plus postage (Oz). This switch is made by a Chinese firm called LEFOO. Item number LF42. Not much info on the web except that its used for remote operation etc.

 

Hooked it up to a test light and blew into it to find it only came on every second time I blew into it??? So pulled it apart.

 

This is the switch

 

 

Note the two white items on the right.

 

When I pulled the switch off the diaphram housing it exposed these peices. One is a small rachet shaped like a hole saw and the other shaped like a space station lol. Anyway they were replaced with a small length of tube. reassembly and it works just as I wanted each time I blew into it.

 

 

With the tube in place

 

 

The discarded internals.

 

 

This will be hooked up to the earth lead of the water injection pump and it will be mounted on the manifold with an extension peice. Rated at 80C temp. dont know the temp a manifold will get up to but play it safe.

[LPGsuperchargedBrumby]

someone else that actually takes water injection seriously....nice....and you found the bit that most people fall down on....a pressure switch that is low enough pressure to be of any use.

 

my old water injection was alot more basic than what you have.....i had a stainless steel 9kg lpg bottle with a 2 inch stand pipe welded on the top that had a 1/2" hose run off the top it that ran to the downstream side of the blower (this pressurised the tank)

 

i then had a small sump welded on the bottom of the tank that had a 1/4" pneumatic line run off through a 0.5 psi check valve to the intake side of the blower where i had a fitting that allowed me have the water metered through a (mikuni i think it was) bike carb jet that let me play with different sizes to get it set right.

 

when the dump/BOV closed i had boost and i had water

 

i was running a blow thru lpg carb so that set up worked pretty well...the only problem i had with it was in the winter frost when the water line would freeze up....but when it was that cold i didn't really need the water injection anyway as going like hell with ice on the road is a bad idea

[tweety]

Thanks LPGSB...I have read a few stories of boost being used to pressurise a tank that would be used to squirt the water. interesting.

 

Some progress after two days working on this trike.

 

I've taken some advice to make certain there is no impeding of the airflow into the carbie. Used the base of the previous smaller airbox and installed a larger outer case.

 

 

But this time air wont just enter from the front but enter at all sides.

 

 

This will prevent the foam trumpet filters from getting wet.

 

 

Intalled most of the water injection system except the injector and pressure switch.

 

 

 

injector line was purchased from a hose retailer. got the 600psi stuff instead of 250psi.

 

So now I have to take off the inlet manifold to install the single injector, get an adapter for the pressure switch to be mounted on the ea81 manifold, fit a relay to the pump and wire up the pressure switch, eventually fir a low water warning light, also a no flow light and get that last dyno tune.

[tweety]

:cool:At a standstill at present. have on backorder a check valve. then get the water injection working then another final dyno tune.

 

stay tuned in 2 weeks

[LPGsuperchargedBrumby]

why do you need a check valve?

 

you have a shurflow diaphragm pump that is a positive shutoff valve....no power, no flow of water

 

hmmm.....thats all assuming that the check valve you mentioned is actually for the water system

[tweety]

Well mate, I didnt know that. Its all new to me. thanks LPGSB

 

So you are saying that the snow performance 220psi pump wont allow water to be sucked under vacuum?

 

If thats the case I can easily cancel the purchase of the solonoid or swap it for something else.

 

I suppose all I have to do is suck on the tube and see if I can draw water?

 

It also means I can actually test the system tomorrow. yippee!