Performance tip for throttle body?

[Iain Mannix]

The Audi 5k non-turbo throttlebody bolts to any A1 CIS VW.
Throttle plates are bigger.

The 5k tb is the same as the Golf tb - afaik, the reason the
5k tb was "the" tb of choice is because there was no linkage
swap necessary; Golfs have the injection on the other side of the
engine bay, so you have to take the little cable-retainer deal
off the original tb and put it on the Golf tb, if you choose
to go that route.  5 minutes, not a big deal at all, and
it seems that junkyards are prone to charging more for an
"Audi" throttle body over a "Golf GL" throttle body;).

85 & up VWs all had the bigger tb, afaik(cis ones, anyway).

Neuspeed's TB is *exactly* the same as the Golf/5k tb, with the
appropriate hardware for the cable pull.

Neuspeed sold their tb with a spacer that adapted the
larger hole on the tb to the smaller hole on the Rabbit/Jetta
early car manifold.  Some said this spacer - 1/2", tapered to
meet the manifold's hole - was a restriction.  So, you can
get a die grinder & open up the manifold to match the Golf/5k
bore.  The backside (big hole) of the manifold gets scary thin
if you make it a straight shot into the manifold; some people
build up material with a welder before grinding; I've had
100% success simply loading that area up with JB Weld before
grinding.  Never gone _through_ the aluminium, but it does
get *very* thin.  Too thin - even though it is not a stressed
portion of the manifold, it gets thinner than one would like.
Think "carbonated beverage can" thin.  In a fit of laziness
and haste between classes during college, we slapped a
Golf TB on a friend's Scirocco with no grinding at all -
the car had noticably better power(not a lot, but it held
more speed up the big hill on 36 from Boulder to Louisville
than it had before - very scientific;), there were no
perceptible reasons to grind the manifold.  The throtle
plates do not hit the manifold, as some people maintain.
We ground the manifold out of principle, but honestly,
for the time & $$ invested - $10 for the tb and 15 minutes -
it was quite worthwhile.

Porting a GTI manifold down by the head can make it crack
over time, too.  BTDT.  About 2" from the head, mine cracked
on 1 & 4.

Anyway.  That's what I know about the CIS tbs on VWs and Audis...



Iain Mannix
86 5kcsq
lots of VW autocross cars

On Wed, 19 Dec 2001, Tom Nas wrote:

> "Rave Racer" <Ravewar at rogers.com> wrote:
>
> >     When I had my 16V Jetta the rumor was the TB from a 5000 would fit and
> >was had  bigger bore.  I never tried it but I drove one that was rumored to
> >have it.  Unfortunately I couldn't verify it, but I did find that it had
> >quicker pickup in the lower revs.  I would guess that it just moved the
> >functional power to a different part of the rev range.
>
> I've heard the same here- the 1.6-1.8 GTI engines benefit from fitting the
> throttle body from a type 44 Audi 100. My info comes from someone in the
> trade, and I tend to take his advice seriously.
>
> Tom
>