Is it worth switch Carb to Fuel Injection?

[BrahmanS]

Hi, I've been thinking about switching from Solex to EFI for my 74 BIG for a while now. I've been driving my 74 daily for about 8 years now. Due to the high fuel prices in Europe for a while now, I've started looking for an EFI. It could be a factory EFI or a Holley Sniper 1100. I just wonder, is it worth doing this? I drive almost more than 50.000 km annually all over Europe. I have been researching for a few days and everyone says something different. Some are in favor of FI and some of Solex. I am really confused. I am waiting for your suggestions.

Regards...
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1974 1303_S BIG
1974 1303 Super Beetle
1983 Golf Mk1

[Dusty1]

I've been studying this for 30 years or so. It all started with a '63 I bought in Turkey. I simply drove it away when it unloaded off the boat. I made it from NYC to the Canadian border on one tank of fuel.

I still have the "miracle" motor in my barn exactly like it was. I wasn't interested in an old 40 horse back then even if it made 50+ mpg.

Part of the trick is a small motor that's tuned. Everything has to be spot on. You need the right cam, compression ratio set to match the cam, a little clean- up work in the heads and perhaps most important, a small tube merged exhaust.

Let's see, a couple hundred for a merged exhaust or fifty bucks if I buy one already rusty at a swap meet.



Then there's the Holley fuel injection. I'm frugal so I get no further than the $900- plus price tag. Nope. Not for me. Effectively it's an electronic carburetor without many of not most of the advantages of modern fuel injection.



You might laugh and point but I like the old Solex 28PCI carburetor as found on U.S. market 36 horse engines. If nothing else a fifty buck swap meet carburetor saves me almost $1000 over the Holley fuel injection.


Hopefully you have a European 1300 in your '74. Use the money you save to freshen up your motor if not rebuild it entirely. Your motor should get 25mpg stock. Convert my target to liters per k if you must.

If it's running properly you should be able to get it over 30 and maybe as high as 35mpg by swapping to the smaller carburetor and a free flowing exhaust. A slight flycut on the heads and a cam swap would get you there for sure.



This thing is pure alchemy:

https://www.cbperformance.com/product-p/1179.htm

We're talkin' 1904cc, 90hp and almost 40mpg. Impossible but they figured it out. It's expensive especially if you have it shipped to Europe but you don't have to. Then nice people at CB gave you a parts list. The important parts are:

The 2228 gas saver special grind cam. This combination isn't going to happen without it.

The interesting parts are the 74mm crank and 5.5" custom rods. That's an easy way to dial in the compression ratio. It gets complicated if you deviate from their parts list.

They should include a merged header with their parts kit. It just works better.

They got close to 40mpg using dual Weber 34ICT carbs and a merged exhaust. Dual carburetors can work better and can be more economical than single carburetors.

You can keep some of you money in your pocket if you source most of your parts in Europe. Don't tell CB Performance I said that. You might get by ordering the 2228 cam from CB and buying everything else in the EU.


I would be interested in three changes to CB's Gas Saver kit:

Use stock 1.1 to 1 rockers arms instead of aftermarket 1.25 to 1.

Build it as a high compression 1300.

Or:

Build it as a tuned 1600.

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[busdaddy]

If I was in your shoes I'd explore the Mexican FI system, I have no idea about the fuel economy, but it's simple, fairly modern and not hard to find parts for.

Avoid the Sniper, single point systems don't work on flat air cooleds.
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[Dusty1]

[busdaddy]

[Lost69Convertible]

Many believe the late 1970s Bosch L-Jet FI has a “digital computer” ECU. But that’s not correct. The ECU is an analog control board. Inherent with analog control is “single state.” In other words, the analog ECU basically does one thing. Its ability to adapt is very limited. And that’s why L-Jet has thermo/time/vacuum/pressure systems that step in to help during cold start and deceleration (AAR, CSV, TTS, Decel valve, Fuel pressure regulator).

Busdaddy is referring to the next generation of Bosch FI with a true digital computer ECU. This is the Bosch DIGIFANT FI system. Because the ECU is smart and multi-state adaptive, many of the complex thermo/time/pressure helper systems are no longer needed.
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1956 Beetle Ragtop: My Father's car
1969 Beetle Convertible: My first car. I loved it, I lost it, and I never got over it.
1979 Super Beetle Convertible

[BrahmanS]

Thank you all for your responses. I know that Holley is a modernized version of the 90-20's injection system. I realize that technically it works well, but I am an originalist and I am in favor of it. Does the Mexican FI' system have an electronic ECU system like the ones used today? I am confused again... There is a Mexican injection system (or something similar) on a website called DUBSHOP and there seems to be an ECU, Crank Trigger etc parts next to it. Especially the fact that it also controls the timing is an exciting feature, but the original Mexican FI still has a physical distributor. What are your thoughts on this kit?

Regards...
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1974 1303_S BIG
1974 1303 Super Beetle
1983 Golf Mk1

[Dusty1]

[vwracerdave]

It's all about the math.

If your carbs are tuned correctly, you will not see any huge gains in MPG or performance by switching to EFI. You will not gain more than 1 or 2 MPG with EFI, in fact you may not see any increase in fuel milage switching to EFI. Simply divide out the cost of the new system you are interested in getting with fuel cost savings at 2 MPG and see how many miles you will have to drive to offset the cost.

In the long run no it is not worth the cost of the new EFI system if all you are worried about is better fuel milage.
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1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK