EA81 supercharger revamp by Tweety

Tweety · Post by **Tweety** » Thu Jun 06, 2013 10:53 am

ok. ea81 oversize pistons will be the go then.

Jonno, if I can extract enough power and torque from the ea81 with SPFI then there is a good chance I wont add boost at a later date. I want enough power to tow my van. The stock ea81 didnt have enough power or torque to do that...the slightest hill had my selecting second on the auto.

Once the suck thru SC12 was installed I certainly had enough power and torque at all revs. And that system produced 100hp at the fly. So a similar output or the 90hp the ea82 SPFI engine produced from the factory would be great.

Hence I am concerned that I must carry out various mods to the new engine in order to ensure I get the figures I'm chasing like higher compression ratio say 9.5:1, the best breathing I can get etc. Some porting if possible etc. But nothing overboard. All this will also make the engine more compatible with the SPFI unit.

I think, from what we have talked about I should do the following:

- oversize ea81 pistons
- shave heads 20 thou off
- possible porting
- SPFI

Is there anything else you guys would do while the engine is in bits to bring the HP and torque up? eg cam

Subydoug · Post by **Subydoug** » Thu Jun 06, 2013 8:27 pm

If your going to go for peak performance without the boost you probably want around the 9.5-1 mark. 40 thou off the heads will get you there with standard ea81 pistons. As far as getting the little ea81 to chuff all its got, head wise its pretty limited. Porting the head wont produce much magic because of the layout of the valves in relation to each other. Even the twin port ea82 heads Normally aspirated are crap because of this reason. Stock ea82 MPFI would be lucky to be around the 100hp at the flywheel. Best you can do is clean up the odd bits and bobs from the sand casting and port match the manifold to the heads.

For maybe a little more kick you might want to research a bit into independent coil packs and mapped ignition.....best bet would probably be the megajolt system.....Id also have a hard look at a megasquirt or something similar..run better sensors on the engine then the 80's tech. You could probably scrape a good 10hp with both those systems, and a massive improvement in all around performance.

Offcourse going into that sort of depth screams EJ swap. Maybe just stick that spfi unit on tweety as she is now and give it a whirl??

Regards

Doug

tambox · Post by **tambox** » Thu Jun 06, 2013 9:49 pm

Be carefull with how much you take off the heads, they may have been machined before.
As you have the motor stripped, CC'ing the combustion chambers and port matching the manifolds adds to smoothness and efficiency.
Every little bit helps.

Tweety · Post by **Tweety** » Thu Jun 06, 2013 10:30 pm

Tambox - CC'ing ...what is that? can I do it in a spa?

Yeh Doug- all that is common sense approach. think you last sentence makes sense. - give the SPFI a whirl.

steptoe · Post by **steptoe** » Fri Jun 07, 2013 7:54 am

not really cc's as such with these heads, more like mlml them

Valves in head sealing, flat piece of perspex is what I use so I can see, drill two holes in perspex, one is tiny as air out hole, other to suit the graduated syringe from your printer ink refill kit, chemist (inqusitive blighters), vet etc, bit of grease or vaso to seal the perspex on the face of the head , start measuring how many mls you squeeze into the combustion chamber part of the head until full - take notes on all cylinders.
Another thing to be sure of is how many thou machined off head from birth, given one head may have been machined and the other not at some stage in the pairs life.

I use trans fluid - guess it will show as a slick in your spa if you spill any

tambox · Post by **tambox** » Fri Jun 07, 2013 8:09 am

Engine castings are done to an "acceptable" tolerance, to save costs. The engines were designed using exact drawings, then tolerance variations were factored in.
In an engine it is generally better to have all the combustion chambers the same size, this improves many parts of the combustion process.
Hence the terms Blueprinting, balacing and CC'ing, you are trying to get the engine built to the original drawings, perfect.
I have done this, not with a Subaru, but with other motors and following a dynotune, they are smoother and more efficient than they normally are.
Once you CC or mlml the heads you can work out the exact compression ratio as you have the volume.
Its not a five minute job to bueprint a motor, that's why OEM don't.

Here's a link to give you an idea.
http://www.diyporting.com/cc.html

And you can do this anywhere you want to, carefull with the water measurements if you are in a spa.

Subydoug · Post by **Subydoug** » Fri Jun 07, 2013 9:08 am

On the heads between the pushrod channels is a little indent, as seen on this pic,

Im not 100% sure but I think that its the indicator for the maximum depth you can safely shave the heads to. When I measured mine it was around 45-50 thou deep. That should be a good indicator if your heads have been machined before.

CC ing the engine will also most likely improve engine response too. I must do it to my heads, just to make sure they wernt on the piss in the shaper, though I was planning on doing it with the block assembled.

Regards

Doug

Silverbullet · Post by **Silverbullet** » Fri Jun 07, 2013 6:05 pm

I always thought it was these little pads on the sides of the head that lets you know when you've gone too far i.e, when you break the surface of these the head is binned.

Tweety · Post by **Tweety** » Fri Jun 07, 2013 6:31 pm

Interesting...actually finding all this info interesting. My intention eventually is to be very knowledgeable on this motor, the SPFI, the heads etc but not necessarily the crank area. I'll leave that to the experts. This will be the the engine that powers my machine for the next 30 years. Even more if I can install continence pads to the seat lol

I have decided I will be delivering my engine to Paul, an engine rebuilder in Griffith (Frog's mate) around xmas time. He has already asked a lot of questions like transmission gearing, what fuel system etc etc.

The closest I got to doing my own mechanical internal stuff was on a Lotus 1600cc twin cam head. I got the cams out by one tooth on the chain cogs and bent four inlet valves. Off with its head again. Then after tightening the head bolts I realised the drain rubber tube between the head and the block wasnt in there. Off with its head again. Them days (1978) the copper gasket was $120 each. An expensive exercise. I realsied my limitations there and then. Hence why the ea81 spare engine's block remains in one piece. lol

H-top · Post by **H-top** » Fri Jun 07, 2013 8:16 pm

I wish you were in Brissy, I'd love to get in on this!

Tweety · Post by **Tweety** » Fri Jun 07, 2013 8:39 pm

A while back H-top we had planned to ride around Oz. Was to catch up with a few members like Toonga and Brumby Kid and others and give them a ride. If that ever happens again the offer is there as it is for any Ausubaru member that can go out of their way to either visit Strathbogie for a cuppa or meet us on that trip.

I'd like to point out that the EJ20 was seriously considered recently. But there are no engine mounts and none possible with this monocoque frame. Hanging an EJ off the box wont please an engineer me thinks.

Here is a VW Beetle trike powered by a Rover 3500 V8 auto. Is in NZ.

H-top · Post by **H-top** » Fri Jun 07, 2013 9:16 pm

Let me know, i'd be keen.

keenly watching this.

steptoe · Post by **steptoe** » Sat Jun 08, 2013 10:12 am

I wonder if your budget can extend to a Davies Craig EWP80 and its add on digital controller to extract those ponies lost from driving the iron-age belt drive water pump.

They reckon a big motor can lose up to 20bhp at top revs, so don't fit one of those Clevo water pumps for better cooling - they give you a hernia just pickin' one up - and their inlet manifolds !!?? Double hernia stuff !!

found website daviescraig.com.au

Tweety · Post by **Tweety** » Sat Jun 08, 2013 5:30 pm

Jonno, according to
http://www.calaisturbo.com.au/archive/i ... 61087.html

as an example there have been problems with these units. Dunno if they have remedied them or not with new models but a lot of negative talk about them.

The concept is good, like the idea of doing away with the thermostat especially with the loooong tubes taking the water to the front of the trike for cooling. An electric pump would cope better no doubt esp at 80 litres a minute. Keeping constant temperatures is a plus too as it adjusts the flow for the cooling required. But $450 thereabouts with controller (which one would want)...cant see it being worth while.

Also what happens with your standard pump? If you do away with the belt around the pulley I assume the pump remains in place, the elec pump would need to be lowest possible point as it isnt self priming. Can the water in the pump go through the pump still without the vanes hindering flow?

Will keep it in mind though mate. You're full of good ideas.

Tweety · Post by **Tweety** » Sat Jun 08, 2013 6:12 pm

and this site offers much discussion in replacing the water pump with an electric one.

http://www.ausjeepoffroad.com/forum/sho ... 989&page=1

tambox · Post by **tambox** » Sat Jun 08, 2013 6:13 pm

The DC water pumps have improved, look at the dates of the complaints.
One of the problems was the EWP80 was to small for a V8, thats why they made a bigger one (ewp115).
I am in the process of setting a an EWP80 for my EJ22 L. I have turned the impeller blades off the OEM water pump, so it has no effect on belts. I am making my own control unit, cheap, using ebay parts.
It seems like a good option. Watch the prices on the pumps as they vary, a lot.
Once you go into water pumps and cavitation problems, you will understand why the DC water pumps are so good.

Tweety · Post by **Tweety** » Sat Jun 08, 2013 8:58 pm

mmm yeh Tambox, I noticed that latest versions have ceramic internals and with new brushless motors they are somewhat bulletproof.

I assume if one was fitted one could make a sort of blanking plate where the original pump is fitted with welded tube for the lower radiator hose. maybe from alloy 5mm plate? the heater connection could be moved.

So many questions!! But there seems to be plenty of satisfied customers out there.

Silverbullet · Post by **Silverbullet** » Sat Jun 08, 2013 9:24 pm

Brushless water pumps eh? whatever next

You'd want to know straight away if that little motor ever stopped spinning, and a special speed controller/driver is necessary for a brushless motor. What was the benefit of removing the thermostat? I thought you'd need one with such long pipes to the radiator so the engine comes up to temperature as quickly as possible.

YouTube · Post by **El_Freddo** » Sat Jun 08, 2013 9:50 pm

Tweety wrote:I'd like to point out that the EJ20 was seriously considered recently. But there are no engine mounts and none possible with this monocoque frame. Hanging an EJ off the box wont please an engineer me thinks.

Gotta ask an engineer - I think you'd be surprised! I've heard of a commodore V6 hanging off the back of a mkII or mkIII kombi box in a baja bug... And that thing was apparently engineered.

Engineers are the ones to ask - they ultimately hold the key to it going through or not...

As for what else I was going to write about - I think I covered it all in our chat today - hope you remembered it and it was useful!

Cheers

Bennie

Tweety · Post by **Tweety** » Sat Jun 08, 2013 9:54 pm

Dont quote me Silverbullet as I'm no expert, have only been reading on this item today. but I believe that when the engine is cold the pump is barely working. See the flow of the radiator fluid is temperature sensitive with a controller. So if the flow is totlly and effectively controlled ther eis no need for a thermostat. Unless you run say a larger pump like a 100 litre/min pump in a 4 litre engine as in the case of the jeep onwer I read up on today. His pump was designed to be used with 5-6 litre engines so it was oversize thereby requiring him to keep the thermostat with it drilled out to reduce flow a little but this was an unusual case. In the case of the EA and EJ size engines the Davis craig EWP80 is the perfect size and the stat can be taken out.