Air cooled VW setup tips?

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gwurr3
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Air cooled VW setup tips?

Post by gwurr3 »

Hi everyone. A few weeks ago I was looking at EFI setups based on MS, but because of the fact that they're not really open source, I began looking for alternatives and instantly fell in love with this project earlier today. I have quite a bit of mechanical, electrical, and computer skills (backyard mechanic, tube amp builder, and amateur unix sysadmin) but I have fairly limited programming skills and I am new to the whole diy EFI/ignition thing. Don't get me wrong, I understand how everything works, I just have no actual experience in doing this. I'm really hoping to get your help and to get this going.

Anyways, I've acquired a '74 bug that needs a rebuilding, and I'm looking to use a FreeEMS EFI/ignition setup. So far it looks like an EDIS and reluctor on the crank setup with a jaguar board would be the best for me, but hey, I'm new; please correct me. The previous owner replaced the carb instead of just buying a damn rebuild kit (among other stupid things) so I ended up with a spare carb to make a throttle body out of.

Here are my ideas so far:

Use stock single carb, single port intake with welded on injector points. Hey, the long extra tubing going up to the ex-carb/TB might act as a good plenum for some torque, right? I'm not looking for crazy performance, mainly just cost-effectiveness.

use MAP and O2 sensors.


Fred, and surely everyone else, thanks so much for making all this possible. I'm looking forward to reading y'all's advice. : )

Btw, I want to say that if circumstances allow me to do this, I will heavily document the whole process and hopefully we can collaboratively make a nice AC VW howto guide.
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Fred
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Re: Air cooled VW setup tips?

Post by Fred »

Air coolers are always very welcome, so welcome to the forum! :-)

I've thought about this many times. My first question was going to be "dual port heads?" but you've already said no. If you put an injector near the carb in the middle, it'll drive like shit. So you have to put one or two at each end of the fork. It may still drive like shit. Or it may work pretty well. Try it and see. Probably the latter. Fingers crossed.

Other than the obvious fuel system setup, the two things your engine doesn't have and does need are:

1) RPM pickup of some sort. You were thinking EDIS, but why bother? How about a 24 tooth wheel with none missing and a single sync in the ex-dizzy hole? Or if you don't want to engineer that, just use the 36-1 wheel on the crank as is and read it directly?
2) Head temperature. You need to fit a sensor to the head that is as useful as possible. I'm no expert on this, so consult the internet and post here, I'm curious and will likely have opinions :-)

Using a Subaru wasted spark coil might be a nice option for you. They've got plenty of poke and are common to find for cheap. em_knaps uses two on his twin turbo lexus V8 powered supra.

Make sure you read this, too: viewtopic.php?f=41&t=1699

And, finally, you're welcome :-)

Fred.
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bradtpt
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Re: Air cooled VW setup tips?

Post by bradtpt »

Fred wrote:2) Head temperature. You need to fit a sensor to the head that is as useful as possible. I'm no expert on this, so consult the internet and post here, I'm curious and will likely have opinions :-)
The six cylinder engine used in the Autralian Ford AU falcon and later models (including BA, BF, FG etc) make use of a cylinder head temperature sensor which has a calibration curve geared more towards higher temperatures. Your typical 026 Bosch NTC sensor will end up very close to a dead short once up over 120 deg C, whereas the Ford sensor is still in the meat of its usable temperature range. As a result, it has poor resolution at temps below zero.
JaniM
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Re: Air cooled VW setup tips?

Post by JaniM »

I have done several different setups on aircooled VW's.
Here is few engines: http://porvwoo.fi/Engines.php

I have 36-1 triggers and bracket for Ford vr sensor. These comes to fuel pump bolts.

One idea, if You want use singleport heads, how about use V-pattern injectors, which sprays both cylinders.
It might work.
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Fred
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Re: Air cooled VW setup tips?

Post by Fred »

Brad, sorry for not denoobing you sooner, your future posts will go straight up.

Jani, damn good idea!!! :-)

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Re: Air cooled VW setup tips?

Post by bradtpt »

Fred wrote:Brad, sorry for not denoobing you sooner, your future posts will go straight up.
Thanks, I saw that last night and thought damn it! :mad:

If I see another Falcon soon I'll grab a FoMoCo part number for that sensor.
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Fred
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Re: Air cooled VW setup tips?

Post by Fred »

That'd be great, thanks! :-)
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Re: Air cooled VW setup tips?

Post by JaniM »

I have added regular water sensor under cylinder. Drill hole to lower tin and put sensor under cylinder air flow like original "thermostat".
Works.
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Fred
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Re: Air cooled VW setup tips?

Post by Fred »

It'll just be quite wrong all of the time, that's all. So your ramp up may be consistent enough to tune for it, incorporating the ramp, but on the flip side, if you let it cool down, then the apparent temp and real inner temp will vary from the usual ratio.

It's true that absolute doesn't matter. Consistency does, with respect to chamber walls, and read temp, and tracking, closer the better.
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
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FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
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JaniM
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Re: Air cooled VW setup tips?

Post by JaniM »

Of course You can't measure real value, only get limit for ASE on M$. But these cht sensors are hard to find or these are expensive.
Is it best place on head under spark plug? Then You get real values on aircooled engines. Then need thermocouple sensor.
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