EA81 SPFI basics

Tweety · Post by **Tweety** » Sun Aug 19, 2012 11:13 am

hahaha

with filtration, when towing I can run a tube from the caravan water tank (60 ltrs). wonder if a cougar in the tank would help?

so if I installed the TN60 20 bar is 6.1 l/hr and I have half a bar (story of my life) then thats about one 40th of 6.1 = 150ml per hour??

With that filtration recommendation one could instal a tank so the end sticks out a little and fill up at any servo.

I think I'd prefer to outlay enough to purchase a 150W 12v pump meant for the purpose. eliminates 3 items- coffee pump, inverter and fan and box (err 4 things). but get the filters, maybe 2 nozzles (one for each throat/) and tank. Do you think the nozzles will be fine mounte on the air trumpets?

steptoe · Post by **steptoe** » Mon Aug 20, 2012 8:48 am

how often are you intending to spray - just on boost? That is /was my idea. As yet have no experience with the jets

Post by **TOONGA** » Mon Aug 20, 2012 9:08 am

somewhere in one of those articles on pressurised injection, there is a wiring diagram for a solenoid switch which turns on the injector/sprayer when the engine is at boost.

Don't ask me which one as I read it over a week ago

TOONGA

Tweety · Post by **Tweety** » Mon Aug 20, 2012 9:43 am

Joel of VW fame sent me a message that he is trying to dig up a system that costs next to nothing to make.

It involves a reservoir washer bottle, a tube from the manifold to it then a tube to the butterfly area. Tube about 4mm thick.

Then at the reservoir end of this second tube there is a hyperdermic needle (available different sizes). When on boost it pressurises the bottle and forces water through to the carbie.

We know filtering is critical. I think the autospeed DIY system is the go personally but to use a 12v pump.

steptoe · Post by **steptoe** » Mon Aug 20, 2012 4:34 pm

surely you could use the 240V in the accommodation wing ?

Tweety · Post by **Tweety** » Mon Aug 20, 2012 4:37 pm

Why? you got a spare house airconditioner Steptoe lol

Tweety · Post by **Tweety** » Mon Aug 20, 2012 4:54 pm

Old fashioned and crude injection of water like those of the oil injection like flashlube is not ideal for water.

This paragraph covers it in autospeed:

The key point is that to cool the intake air, the water must evaporate – it is this change of state from water to a gas which absorbs the energy. And the key to getting water to evaporate is to use very small drops – an atomised mist – which dramatically increases the surface-area-to-volume-ratio of each drop, promoting evaporation.

So I will seek the cheap option of proper spray nozzles.

First decision made.!!!:)

Think I'd prefer to have full time water injection so no need for a pressure switch that would enable water injection only on boost.

Second decision made

Spray nozzles of a certain fixed size eg .030" cant be adjusted. This elinimates a need for a knob adjustment method. However a glass tube system like flashlube type would eb desirable as you can see the water dripping and the rate it drips. So a glass tube is desired. No adjuster required

Third decision done

Filters. There will be the reservoir then a plastic type cartridge fuel filter for larger bits to get trapped. then the pump. After the pump a fitler we have discussed $43 ebay- cartridge fridge water filter by autopro. then the nozzle/s.

Pump. I will look further into this for a correct size. likely 150W 12V for ebay there was one AEC for $114.

Questions outstanding are:

1/ How many nozzles? Two one for each throat of the Dellorto would limit chance of both clogging. We will be retuning the engine leaner so clogging can lead to leaning out and disaster. So two x .030" (note this size nozzle has a note in autospeeds site "barely atomises". But trial and error here. Might have to go 2x .060)

2/ Nozzle location? Nozzles should point upwards. I prefer the trumpets prior to the carbie. Then there is the post butterfly area on the alloy manifold. Anyone think od the best spot?

3/ Windscreen washer bottle. Anyone know od a large capacity square shaped one with low level warning light? I would buy a new one.

Tony

littlewhiteute · Post by **littlewhiteute** » Mon Aug 20, 2012 6:19 pm

Have done water injection for years, don't bother with anything crude, especially for a boosted engine.

I will be buying a system from AEM electronics in the USA for my WRX.

The biggest issues are flow start point and total volume over the boosted range of the engine.

For that, you need electronic control, which AEM and other competitors do.

Tweety · Post by **Tweety** » Mon Aug 20, 2012 9:50 pm

total volume over the boosted range of the engine.

For that, you need electronic control,

even for a non EMU ea81 ? Gary?

I took tweety for a ride tonight. I had fixed the air leak that dogged me. so it is still running rich for sure. A good sign as better economy isnt far away. but it was pinging a little uphills.

Retarded it 2 degrees at a time. 4 degrees nearly got rid of it. Then a little more and the pinging disappeared across the range. Performance, easy revving is spot on, idle great. all good.

so I'm eager to get into this water injection mod and then another dyno.

Let me say, compared to the VW engine and the ea81 NA there is nothing like being able to oversteer a little with power on to go around a bend without moving the handlebars. Stopped dead, full throttle....front wheel lifts 50mm in the air for 5 metres, smooth easy to handle power. A little touchy with the throttle at low speed is the only drawback. Havent towed yet but think wheelstands then might be the norm....save wear on that Rod tyre...

Tweety · Post by **Tweety** » Fri Aug 31, 2012 9:10 pm

Sorry littlewhite ute, I've reverted back to the Supercharger thread with this water injection project.

steptoe · Post by **steptoe** » Fri Oct 04, 2013 11:19 am

OK, I searched spfi and tweety and got this - title was spfi basics , wasn't it ? Gone a bit off topic and stale... but still an appropriate spot to post up what I have found with an EA82 spfi inlet manifold - externally, the tube casting is about 6mm greater than my EA81 carby inlet manifold. Makes me think the walls are likely same thickness, so may be an extra 6mm ID for air to flow into the old EA81 of Tonys Tweety. Goes hand in hand then with the extra 6mm gained from fitting an L Series EA82 Y pipe to the other side of the heads. Currently stripping my little baby down to clean up things and hook up the LPG stuff

Tweety · Post by **Tweety** » Sat Oct 05, 2013 1:39 pm

good to know, that one day when I'm much older my SPFI manifold will be a collectors item....lol

steptoe · Post by **steptoe** » Sat Oct 05, 2013 6:51 pm

I think they already are a collectors item in the US - saw one going for $100 - then postage will be a little around the US$122.50 mark .....

Tony, did you see the usmb post where one guy suggests WRX 2.0 pistons in an EA81? Their oil return holes rather than slots an advantage. Wonder what it does to compression ratio etc

tambox · Post by **tambox** » Sat Oct 05, 2013 8:19 pm

It would be a much more enjoyable world if we had the time and $ to test these theories out.
On paperwork or in the head, they seem good, but in practice??
It would be fun to play.

steptoe · Post by **steptoe** » Sun Oct 06, 2013 7:19 am

Ivans imports on USMB has built said 2.0 pistoned EA81, using rebushed gudgeon end to suit - revved all day apparently !

Tweety · Post by **Tweety** » Sun Oct 06, 2013 7:33 pm

Interesting jonno. Will do some reading.