50mm info (mainly for Rick K)

[roccit_53 at scirocco.cs.uoguelph.ca (C Boyko)]

Well, I thought I'd post this to the list since others may find it
interesting.

>From a note to the list, regarding 16Vs intake manifolds. It should be in
the archives, it was originally posted Sept 06/01, but  I?m just retyping
it. (Excuse the typos!) The original thread was about a 1989 16V I?d seen
in Toronto which clearly looked to have the TB/airbox etc. FACTORY
installed on the passenger?s side, as you?d expect in a Golf/Jetta, and
yes, we had them in ?89 in Canada.


>From Dirk:
European 16V:
The Scirocco 16V always had the intakes on the drivers side until its very
end in 1992. There are no exceptions.

The 50mm intakes were only sold on SOME KR-engines from 1986-1988.
Most KR engines (and all 1985 ones) came with the small 40mm intake.

The 50mm manifold was introduced by VW in 1986 because they had problems
to reach the claimed 139hp with the small manifold. There was a strong
public (motor press) interest in that topic VW blamed to cheat the
customers with wrong figures and they had to react. So they introduced the
50mm manifold.

When catalytic converters became mandatory in Germany in the late 80's VW
had to change the cams of the 16V to a more moderate version to protect
the cat from getting too much unburnt fuel. That is the main difference
from the PL to the earlier KR engine. Due to the more moderate intake cam,
the 50mm intake was rather useless and even had a loss of torque at lower
RPM. So it was replaced again by the smaller 40mm intake. The max. HP
figure of the PL engine was corrected down from 139 PS to 129 PS then.
Conclusion: When using a 50mm intake on a PL enginee it?s strongly
recommended to change the intake cam to at least a KR timing version.

1) All Sciroccos with catalytic converter came with the PL engine here
2) All Sciroccos with PL engine had the small 40mm manifold.

For this reason, the 50mm intakes are also a rare and wanted item in Germany.

Greets, Dirk, 16V KR ;-))

Okay, so there you have it, essentially what Allyn already said with some
history. Looks like 10hp from a mild cam, the intake, and no cat. I?d
guess with a 2L and a more aggressive cam, there would be more benefits/
less down sides. I don?t have any low end concerns with my 50mm on a 2L
with a Euro cam, but can?t say what it would have been like with the 40mm
intake, cause it all went on together.

Also, it should warn you to check out exactly what you're getting if you
get a European cam (could be our PL version) or a KR intake (could be a
40mm)

Now, the other 50mm trivia I picked up on the way was from European Car,
Nov 2000. I copied the article since they had done a bunch of cam
comparisons on a 2.0L/1.8 head 16V, (about a dozen combos), with other
goodies in the mix. In the text, they mention that going from the 50mm to
the stock intake results in a drop of ?a whopping 14 hp?, but if you read
carefully, they also bolted the stock exhaust back on in place of the
headers and other exhaust goodness. So who knows how much is from what,
and they didn?t say which cams were in when they got the drop, presumably
the ones with the highest output on the dyno. They make reference to a
dyno for the intakes, but there isn?t one printed with the article.

But in 2000, I was impressed to still see comparisons done on our engines,
given that the 1.8T was still quite new and tempting to focus on.

So there you go, no big tales of disaster this time. A 50mm intake is
pricey, but at some point you go from cheap thrills to determining how
much gain is worth how much money I guess.

Cathy
1987 2L 16V Scirocco - the Silver Headache
1979 1.8L 10:1 8V - Klaus- sounds like half a Chevelle plus a Weedeater
"Misery loves company" (Old Proverb)