EA81 supercharger revamp by Tweety

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Tweety
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EA81 supercharger revamp by Tweety

Post by Tweety » Sun May 12, 2013 6:17 pm

I'm a bit early! Likely commence this project next year as I have some chassis issues to get through first and expenses to overcome. Nevertheless my next project involves purchasing a late model EA81 for total rebuild (not by me, I dont know what a Gudgeon is!).

Regular members will recall my Panther trike with 3 speed vW auto Type 3 Box. The 1916cc VW engine was sold off after many issues. I purchased a used EA81 from a subaru mechanic that had renewed rings and bearings 80,000 kms ago (now 110,000). I ran a weber (that Brumby kid ended up aquiring) and electronic dizzy rebuilt.

I wasnt fully happy with the result. The EA81 would rev much better than the twin carbed (webers) VW engine and had a little better acceleration. Economy was good at around 8l/100kms to 11l/100kms. But hook it up to my mini caravan and the slightest hill would see me dropping it down to second gear. It just didnt have the power and torque output required. This is despite the trike weight of 550kgms and a van weight of 520kgms total 1070 kgms and a little extra parachute effect from the trike roof. The auto box, as seen on the dyno, sapped 14hp from the engine. Outputs were NA 59hp, SC12 82hp ATW.

Many said I should have gone EJ20 or similar and have some regret I didnt. However as I've now settled with the EA81 and spent lots on the exhaust etc I want to stick with this very simple engine.

Image

I bought a Toyota SC12 and being mechanically inexperienced still managed to install it suck through with a 40DCOE Dellorto. This was eventually dynoed for jetting and dizzy reset for boost. Custom twin exhaust had connecting pipe etc. So I've done all the right things. The extra power throughout the rev range is impressive and totally satisfies me at 5psi boost and I could raise that to 7-8psi without risking reliability. What I wasnt prepared for was the poor economy.

I want to fix the poor economy. I want to be legal eg engineers report easily obtained. I want the whole mechanical driveline to be oil leak free, painted and even parts chromed. This is near a show trike so why not get it looking like one? So an extra auto box and transaxle might be sort also and the whole lot fully assembled prior to install. As the trike is operational I dont care how long this project takes and expect this thread to have its quiet times as I save for the next development.

My plan briefly is this:

Buy a EA81 for rebuild keeping in mind it will be built for boost.

SC set up will be blow through. Buy a sealed carbie preferrably downdraft this time, a single throat will do maybe a Holley or ready sealed units like Mighty Demon. http://www.wpsracing.com/ca750cfmmide.html
Upgrade the Sc to either SC14 or if funds are ok to a sprintex twin screw SC. SC's like the Sprintex are much more efficient and run cooler, essentially they sap less power to turn but I dont think they have a on/off switch pulley set up.

The other alternative is to go EJ20. I'll be frank and say I dont want to do this. I'd be discarding my $1600 exhaust system or chopping it, and the eCU/EMU etc etc scares the crap out of me even though I know my mate Bennie would help me join those wires up. The other reason is that the eA81 like the vW engine hangs off the transaxle and on a monocoque chassis from Panther there is no way you can have engine mounts. This might give an engineer a headache and me many regrets. And remember- I'm happy with the EA81 SC12 output.

There is no alternative with the auto box. The trike was built around it and therefore fits like a glove. The auto Subaru boxes are at least 140mm longer requiring the rear wheels to be moves aft that much (Up front the tank is in the way and not able to modify). The swing arms are hand made alloy box section and would need to be longer. It just isnt worth it and could spoil it.

So, a similar refined set up like I have now with much better economy is the goal. As 90% of the time power needs are low like cruising without towing a switch for instant boost is I think the way to go.

Your thoughts?

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Image

Tony
[SIGPIC][/SIGPIC]Tweety trike- EA81 (full reco 2014) 32/36 weber, SPFI manifold, 9.5:1 CR, VW auto.

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Gannon
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Post by Gannon » Sun May 12, 2013 7:25 pm

If you want forced induction and fuel economy, I have 2 words for you.... fuel injection.

The wiring is easy, especially if somebody in the know can do the hard stuff for you so you only have to plug it in (see my signature below)

Your 3 options are....
1- Buy the required EA82 SPFI parts from the USA and add them to your EA81 and have the loom shortened to fit your trike

2- Buy a EA82 MPFI and replace your EA81. You can still keep your exhaust this way.

3- Add custom injectors to your current EA81 manifold and run aftermarket engine management.

Option 1 and 2 wont really need any tuning because there is enough headroom to allow for the extra air flow. Option 3 will need dyno time to tune properly which could add up.

My pick would be number 2 as this will give you about 100 wheel hp and has electronic control of both fuel and ignition. Parts are also still easy to come by
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Post by steptoe » Sun May 12, 2013 8:14 pm

Tweety wrote: being mechanically inexperienced
Pah, pull the other one .....

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Post by Tweety » Sun May 12, 2013 8:48 pm

inexperienced with internals of engines jonno.lol

Yes I like option 2 as well. now I'll start reading up on the EA82 mpfi. Which was the reason for the early post- being pointed in the right direction of possibilities. thanks Gannon.
[SIGPIC][/SIGPIC]Tweety trike- EA81 (full reco 2014) 32/36 weber, SPFI manifold, 9.5:1 CR, VW auto.

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Post by Subydoug » Sun May 12, 2013 9:09 pm

Tweety, forget the carby mate, Il send you a fuel injection system to stick in you trike if you like.

exibit "A"

https://www.youtube.com/watch?v=cyA1i2p_TQs

Just let me get it working reliably first and then Il box one up and have it in the post for you ;), that's if your interested?

Regards

Doug

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Post by Tweety » Sun May 12, 2013 9:45 pm

You're on. Would save me a bit of heartache. will message you Doug.
[SIGPIC][/SIGPIC]Tweety trike- EA81 (full reco 2014) 32/36 weber, SPFI manifold, 9.5:1 CR, VW auto.

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Post by 1111giles » Mon May 13, 2013 3:05 am

Subydoug wrote:Tweety, forget the carby mate, Il send you a fuel injection system to stick in you trike if you like.

exibit "A"

https://www.youtube.com/watch?v=cyA1i2p_TQs

Just let me get it working reliably first and then Il box one up and have it in the post for you ;), that's if your interested?

Regards

Doug
What is this ??
The link took me to a very dark screen and could only hear the engine noise and see the laptop stuff.
I like the idea of fuel injection and s/c for my Ea81 :D
Can you postmore detail of what you have here please ?
Thanks !
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Post by steptoe » Mon May 13, 2013 7:19 am

then the EA82 mpfi sets you up towards EA82T being mpfi :)

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Post by Subydoug » Mon May 13, 2013 8:56 am

1111giles wrote:What is this ??
The link took me to a very dark screen and could only hear the engine noise and see the laptop stuff.
I like the idea of fuel injection and s/c for my Ea81 :D
Can you postmore detail of what you have here please ?
Thanks !
Yeah, Iphone at 7pm doesn't work so well. Clip wasn't really meant for the forum, but for someone else. Its my ea81 running on EFI. More to come later when I get it working better. Its that annoying revving stuff now :rolleyes:

Tweety you could even pick up a ea82 turbo block and run your supercharger. That would keep all of the exhaust the same and give good enough power and torque to tug the camper around. EA82 head design on the mpfi and turbos is far superior to that of the standard ea81 so even a boosted ea81 isn't going to go like the ea82.

Did you ever add a recirculating bypass valve to your current setup?

Regards

Doug

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Post by Tweety » Mon May 13, 2013 10:31 am

Recurculating bypass valve? dont ubnderstand. I installed a catch can? if thats what you are refering to Doug?

Yes, the ea82 MPFI seems the go. I like the concept keep that nice exhaust. At around 97hp add the SC14 blow through and it could be a winner. Might even be ok without the SC.

In the meantime I'll keep reading your EA81 FI project.

Hey 1111Giles- read up on my thread done 12 months ago re supercharged ea81 in trike. And Dougs current Fuel injection EA81 thread. The suck through SC12 has been in my trike for that time now and has been running flawlessly with heap of low down grunt and overall performance. Just the economy isnt so good. Hence blow through set up sought and that has led to MPFI engines.
[SIGPIC][/SIGPIC]Tweety trike- EA81 (full reco 2014) 32/36 weber, SPFI manifold, 9.5:1 CR, VW auto.

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recirculating bypass valve

Post by steptoe » Mon May 13, 2013 10:59 am

http://www.ebay.com/itm/BYPASS-VALVE-AU ... 2619942%26

me thinks

and to stop fuel drinking you need to reduce the air being pumped in all the time at boost levels

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Post by Subydoug » Mon May 13, 2013 11:57 am

Yeah exactly what steptoe linked. you plumb that as a bypass across the sc and it stops the engine boosting during coasting and idle. It should improve fuel economy until you can get your hands on a mpfi ea82.

Regards

Doug

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Post by Tweety » Mon May 13, 2013 1:33 pm

Ok, so this bypass I assume is mounted on the manifold between the SC and the intake or on the intake itself then is plumbed back to the air filter? I assume it is a pressure switch that closes on high boost and opens at low boost?
[SIGPIC][/SIGPIC]Tweety trike- EA81 (full reco 2014) 32/36 weber, SPFI manifold, 9.5:1 CR, VW auto.

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Post by steptoe » Mon May 13, 2013 3:09 pm

simple spring inside. This one ? comes with different springs and shims, or maybe was the plastic ones ??

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Post by Tweety » Mon May 13, 2013 3:18 pm

So Jonno, bit like my blow off valve for backfiring but works in reverse and on less pressure? and my plumbing is correct?
[SIGPIC][/SIGPIC]Tweety trike- EA81 (full reco 2014) 32/36 weber, SPFI manifold, 9.5:1 CR, VW auto.

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Post by Subydoug » Mon May 13, 2013 6:01 pm

Here you go tweety.

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Bypass needs to go back between the carby and the supercharger.

Regards

Doug

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Post by Matt » Mon May 13, 2013 7:15 pm

Just going to throw this in to, The EA82 is a fair bit wider then the EA81 which may be a problem for what i can see of the exhaust in the pics and i believe it is deeper to thanks to the timing belts too. Might be worth a measure.
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Post by Tweety » Mon May 13, 2013 8:37 pm

Matt you are spot on. The rocker covers have just enough clearance now to get past the mufflers.
I've thought a fair bit about this and think it would be feasible still, an exhaust guy to cut and weld the exhaust as required to get it all to fit. Will inspect it all tomorrow. If it is too much trouble then I'll shelve the idea of EA82 because the EA81's compactness and ease of service etc is one reason I went that way.

Sorry guys in being non committal but this is the reason behind the thread.

Then there is the bypass valve install. Am keen on this. Living in an area that sees me hitting the Hume freeway often and cruising being my style of riding this bypass idea might just get me the desired fuel savings. Then (long term)I can obtain a spare EA81, rebuild it and install a blow through SC system with on/off switched clutch.

Really appreciate your ideas.
[SIGPIC][/SIGPIC]Tweety trike- EA81 (full reco 2014) 32/36 weber, SPFI manifold, 9.5:1 CR, VW auto.

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Post by El_Freddo » Tue May 14, 2013 10:39 pm

Matt wrote:Just going to throw this in to, The EA82 is a fair bit wider then the EA81 which may be a problem for what i can see of the exhaust in the pics and i believe it is deeper to thanks to the timing belts too. Might be worth a measure.
I'll also throw in that the EA82 has twice as many areas for oil to leak from than the EA81!

I'm wondering if we could setup the EA82 MPFI fuel injection system on the EA81 - the dizzy will fit with some mods, the wiring loom can't be that hard (and I've got one or two of them lying around!). The hardest part I can see the mounting of the fuel injectors in the EA81's manifold. OR making up a set of adaptors to fit the EA82 MPFI intake on the EA81... I'm just thinking openly here as I think this would be the best way to go - factory system, can't go wrong unless you fit it in correctly!

Before anyone jumps on the 4 injector two ports thing for the EA81 - the MPFI is a batch fire setup, two injectors fire at the same time.

Got plenty of test vehicles to work it out on anyway ;)

Cheers

Bennie
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Post by Gannon » Wed May 15, 2013 9:08 am

With the diagram that was drawn above, the small vac line to the bypass valve must be connected after the throttle. i.e. so it sees vacuum when the throttle is closed

As Bennie said, because the injectors are batch fire, you could fit 2 injectors to each side of the manifold, just above the head
Current rides: 2016 Mitsubishi Triton GLS & 2004 Forester X
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Past rides: 92 L series turbo converted wagon, 83 Leone GL Sedan, 2004 Liberty GT Sedan & 2001 Outback
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