RE: "Wimpy" NG engine??

["Bruce Bell" <bbell04@ibm.net>]

There is a known data point for moddin' this motor.  You need to back to
1986 in EC (or was it VW&Porsche then).  The motor was a 4cyl VW 1781 cc
with same compression, valve sizes, knock sensor etc. and almost the same
displacement per cyl.  Dyno'd by tectonics this motor with Schrick 268 (272
is very similar), a supersprint exhaust, and initial spark advance set to 12
deg. the motor made 118.6 HP @5500 rpm. 118.6/4*5=148.25 hp and if you
correct for the extra 3.6% displacement/cyl you arrive at 153.6 hp.  Clean
up the head and ports, perhaps EH the IM and you (for a considerable
investment) may see 160-164 hp depending on the quality of work done.

On valve sizes, 2v/cyl is not a benefit over 4v/cyl. 2 24mm intakes at an
11mm lift will have a valve curtain area of 1658 mm squared while a 40 mm
valve at the same lift provides only 1382mm squared. It is not the area of
the hole but the circumference * lift that breaths. I can't remember the
intake sizes for the 4v heads so I used 24 mm to be conservative. The
biggest valves I have heard of in a 2V motor is 42mm intake and 35 mm
exhaust and most tuner DO NOT recommend this for street use since the
clearance between the valves is so reduced that head cracking (familiar to
early Urq owners) becomes a major problem.

A couple of years ago I looked at an NG at Santa Fe in Castle Rock Colo.  I
was most unimpressed with the stock downpipe and cat. The outlet on the
downpipe appeared to be no more than 2" compared with the 2.5" downpipe on
the 4kq. This is the place to start looking for power.

HTH

Bruce  (Who thinks the NF/NG is a great place to start for a NA I5.)



-----Original Message-----
From: owner-quattro@coimbra.ans.net
[mailto:owner-quattro@coimbra.ans.net]On Behalf Of Richard Beels
Sent: Friday, September 25, 1998 1:37 PM
To: quattro@coimbra.ans.net
Subject: Re: "Wimpy" NG engine??


I was relying on a quote from a tuner catalog I got a while back from some
company in England.  Can't really remember the name: TSM, TSW, TSR,
something like that (maybe Phil can chime in?).  I do recall that they
offered a head with larger valves and this was one of the "benefits" of the
2V/cyl config vis-a-vis the 4V or 5V/cyl (no room to enlarge).

It's difficult to get much more power out of the NG without spending lotsa
bucks or replacing the thing altogether.

At 02:18 PM 9/25/1998 ,  Fluhr was inspired to say:
>
>  >The NG puts out about 130HP.  One major problem is the fact that the
head
>  >has 40mm inlet & 33mm exhaust valves and a wimpy camshaft.  You can get
a
>  >re-worked head for $1500 that majorly increases valve size, drop in a
new
>  >cam for $400-500 and get 170hp.
>
>  What larger valve sizes are you talking about, here?  I thought the NG's
>  valves were decently sized as-is.


Cheers,
	Richard
	88 90Q - <insert pithy witticism here>
	88 Golf GTi - PRO Rally