PiCT 30-3 carb & Single Port Heads - How Big

[J-Gaz.]

Well, the time has come for me to tear down my 1600. (or at least build a plan to)
I've got an oil plug leak on the front of my engine that I had Epoxyed over to "Fix" - which was temporary, but I think the time has come to take it to the machine shop and have it drilled out and fixed properly.

That said, my 1600 doesn't have that many miles on it. Over the last few years, although I didn't track exactly, I'm sure I've not put 10,000 miles on it. There seems to be something wrong more often than not...

But, I've been chasing those gremlins and handling them accordingly through the years... Dive a little, chase gremlins, Drive a little, Chase...

My question is, how big can I go, maintain good MPG, and use most of what I've got already, like the Single Port Heads, and the PICT 30-3.

Years ago I was following DB&HVW's Mileage motor, and fell in love with the idea
https://indd.adobe.com/view/cae93716-d479-4176-8bc3-495d62660628

I'm curious if I can swap a crank, cam, P&C's and go a bit bigger, but still have the reliability and torque of the single port and run a single carb.

Viable?
1641 should be easy, but not sure it's worth it.
What about 1745 with the 5 1/2 pully etc of the mileage motor?

Silly or super doable?
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1970 Beetle | Basically Stock 1600 SP

[J-Gaz.]

Looks like, according to this article, 1745 with a Solex PICT 30-3 could work... Might be a touch small ...


1745/56.57= 30.846738554

https://www.doghouserepair.com/store/item/11839/wsc-what-size-carb-for-what-size-vw-engine-formula/
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1970 Beetle | Basically Stock 1600 SP

[Lingwendil]

Might be better to go up to the H30/31 for the bigger venturi.
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[J-Gaz.]

[Alstrup]

The only way you will make an engine like that do any significant improvement of fuel efficiency is to increase total gearing so the engine revs slower, so you prevent it from zipping from the main circuit.
It would be better to stay 1600 and improve the efficiency of the package.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[J-Gaz.]

[Alstrup]

You are correct. If you do as you laid out (with the 1745 and 30 pict carb) you will pull the engines torque area downwards, which means that you will need to bring the cruise rpm down also in order to benefit from it.
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[modok]

The intake manifold is limiting breathing for sure, so increasing the displacement just moves power & efficiency down to a lower rpm.
A larger intake is an easy gain but that will need some kind of larger carburetor also.

With the intake and carburetor as a limitation you might actually want to go smaller CC.
The 1300cc was known for very good mpg, but not much for acceleration

[Alstrup]

Actually, a 1776 with such a set up can run surprisingly well, sort of like a 1200 on steroids. It does run out of breath very soon. But if done as I wrote it can work well. a "freeway flyer" transmission is almost a must.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[J-Gaz.]

Appreciate all the feedback.

I like doing 90 on the highway when needed, and don't want to lose that top-end zip.

As it is, the car is really a fun drive. I'd love to just get a bit more MPG out of it, and since I've got to split the case to repair a leaky oil galleys plug, I figured now would be the time to upgrade.
I don't see myself spending even more money swapping the transaxle to a freeway-Flier.

That said, I guess I'll focus on a couple of things to maybe just try to eke out a few MPG with it as a 1600 and not try to get too fancy.

35mpg would be a dream.
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1970 Beetle | Basically Stock 1600 SP

[oprn]

I would not personally waste my money on a so called "freeway flier" as they are nothing more than a late model type 1 transaxle with a fancy, feel good name and a big price tag. Just run taller tires if you want higher gearing.
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[J-Gaz.]

HA! Yeah, I've heard similar - and that there's no real spec for what a Freeway Flier is - could be any number of switched up gear ratios i guess.

Funny you mention running taller tires, I'm all stock, and maybe because so many bugs are lowered, people think mine is lifted!

[vwracerdave]

[oprn]

[J-Gaz.]

@ vwracerdave, I said "When I have to"
I drove pretty economically. Very grandmotherly, actually.

But being able to go fast when needed is a safety thing, just like having great breaks. I don't want to lose the ability to go at speed when needed.
If building a bigger CC motor, but the small carb lowers my range of speeds and conditions I can drive in - and top-end speeds - then it's not worth it.

Last I checked I was getting about 33 MPG on long trips and less in the city.
35 would be great, 40 would be better... But I'm not about to rebuild my whole car for the pursuit.

Hope that makes sense

[J-Gaz.]

Since I've got to pull it apart to fix the oil galley plug, Could it make sense to put in a "cheater" cam, and ratio rockers?

I'm not going to make the engine any bigger, but figure I may as well see about any opportunity to upgrade while its apart.

any idea of what that might do to performance and MPG?
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1970 Beetle | Basically Stock 1600 SP

[Alstrup]

Plenty. But you wohnt like it.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[J-Gaz.]

Not worth it? Why wouldn't I like it - tell me more.

[Alstrup]

Improving such an engine is not a simple "take it apart and put it together again with a different cam" Well, you can, but it wohnt get you far.

There are two ways of making an engine more fuel efficient:
1, the Berg way. Making the engine so low compression that it looses its grunt and you thereby can lean it out because it cant make much power. (You can basicly think VW 30 & 36 hp.)
2. You can make the engine efficient and control both ignition and fuel induction better and thereby get more power and better efficiency.
The latter can, in 90% of the cases NOT be done in an average garage. It requires machinery and knowledge to get you there, which very few have, because most are "only" interested in making cheap power and be done with it. That said, if you are willing to send your heads out for detailing, Get your rotating assemly balanced (all of it) swop the cam, improve your ignition, detailing your oil system and either buy a better muffler or cut your own open and redo it inside, we can set you up to get a very efficient and quite powerfull (for the parts involved) little 1600. Somewhere around a true 65 hp and 125 maybe 130 Nm torque. A stock 1600 sgl port is rated 47 hp (Din) Back in the days I saw them pull 46 to 50 hp in stock form. so the above will be a true 15 hp increase with a 3-400 rpm wider powerband.
But that´s what it takes to do it when you want to keep it basicly stock on the outside. There are no shortcuts, apart from swopping to a set of twin Solex, Kadrons or even ICT´s if you have the knowledge to trim those suckers.

This below is a stock 1600 sgl port industrial engine which was prepared for the street, where I gave it a basic 3 angle seat job, dressed the intake valves, increased the CR to 8-1 and replaced the carb flange to accept a 34 Solex. Stock Leistritz or Ernst muffler. (I can´t recall. Its been a while)
All that gave us 6-7 hp and 300ish rpm wider powerband.

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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[J-Gaz.]

Thank you for the detailed response.
That's a lot of work for 6-7 hp.

Any mods or updates I should consider while the engine is apart?
Sounds like it's not worth it to put in a cam or ratio rockers.
What about full-flow/ remote oil filter?

I'm just asking because it's coming apart and I may as use the opportunity to add any performance or mods to help "Bullit Proof" it.

If the cheater cam and ratio rockers would net me 10 more horsepower and not impact MPG, and get more "Fun" driving, or even more power up mountain passes that would be cool.

Also if it got me better MPG, I'd be into it - but sounds like it's not worth the hassle.

When I first built my motor in 2008 I believe that by just using the parts as they came from the parts house, when I measured 7.1:1 CR and on the #3&3 cylinders 7.4:1

From one of my posts: May 20th, 2008