cr limits on pump gas?

[BFB]

since some of yall seem to be getting sidetracked and trying to make this about answering something that wasnt asked, i highlighted my original post to try and make the question clearer.
" what is the max c.r. a vw engine can run" was never the question.
we all know there's to many variables we can get hung up on, so i tried to word it so we wouldnt and could just b.s. and see what some ppl can do.
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An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1

[Brian_e]

[ekacpuc]

If I was the OP I would read up on dynamic compression ratio and squish. Try to form your own opinion. There’s no hard set rules. Try to not go crazy with DCR and keep squish within .040”-.060”, make sure you keep the combustion inside the chamber and the better the fuel control the higher static compression you can run.

It is all debatable. I run 9.6:1 with a web 252 and dellortos and have ran 87 just fine with full advance set at 32 degrees. I did make sure to keep a tight deck and I have a .060” “head gasket” with the piston poking up .020” above the top of the cylinders to try to keep the combustion inside the heads. 90 is the highest you can get here and that’s what I normally run. However I’m at a place where a hot summer day doesn’t exceed 90 degrees Fahrenheit.


Lots of old school guys going with the gene berg advice still.. nice thing about a VW is it’s easy to adjust deck.

[Brian_e]

[evanfrucht]

[stevemariott]

[evanfrucht]

Fair enough, but one can have a lot of experience and still be wrong sometimes.

And yes many race cars also use pump gas around town
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[ekacpuc]

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[vwracerdave]

[evanfrucht]

Fair enough, pump gas is for the street and that's probably one of the reasons very high performance street engines might be able to get way with more than 9.5 CR. A lot of times the peak power is reserved for more spirited driving, but it's not a race track even then. Much of time you will be forced to keep things in the lower RPM's when putting around town due to common sense and safety reasons.
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1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )

[ekacpuc]

[modok]

how much "CAN YOU" run?
Sounds like a personal question, and a challenge.

How much DO YOU run would be a more concrete question.

I can think of a few engine designs that would NEED over 10-1 to run pump gas.
CAN I build those? probably yes. Especially if you talk me into it and pay for the parts.

[Zed999]

I think the closest measurable comparison of would be cranking psi?

[ac509]

11.2:1
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Dumber people are doing harder things everyday.

No one questions a 73' Volkswagen?
I have a '73 Volkswagen and it is nowhere near 73' long!

[mark tucker]

I would think a 16:1 would start on pump gas...and probably 18 or higher too.if thats the question your asking.especaily if your running E85 pump gas...

[ac509]

[vwinnovator]

no issue running an FK-10 and 11:1

I used to listen to berg when I was a kid..

but when they preached "nothing over 90.5's" while gary was running nearly 2500cc his story went out the window...

pluto used to be a planet too...

[mark tucker]

also it's very important to not build a hp vw engine like a vw engine. perhaps thats why somany vw junk piles are at the swap meats from the clueless ones building vw's

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