Date: Mon, 13 May 1996 22:59:20 -0500
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: vwbus@TCPBBS.COM
Subject: Type 4 FI performance ANSWERS
Well here are the results for anyone interested in what
generally one may do to a 2.0 T4 and keep the FI as
handed down by the major T4 players.
AVP, Leonard says do nothing, I sort of trust this guy
really seems to know his stuff, he has the most reasonable
arguement against powerful T4's says that cooling is only
marginal now and increasing displacement not to be tolerated.
In fact they open the pocket in the heads up a little to further
decrease compression on their head rebuilds. Still he is in
the business of building stock motors and is not interested
in selling you more and since he wants your business may
be a bit biased. Plus people do build 3.1 monsters and they
only blow up every other day so.
Stephens, says best way to go is go for 96mm jugs, unfortunately
if anyone noticed, 96's up and just about dissapeared somewhere
between 1995-present. Stephens has none, apparently the maker
NPR of the cast sets must have quit doing them, these were the ones
formerly available for $350 or so, little more than 94's. They say the
bad rep was overated and that the major problems could be eliminated
by carefuly retorquing the heads after break in to avoid everything
loosening up and cutting in. Stroking is reccomended but requires
shims and the purchase of crank and jugs so 96's were cheaper option.
Anything under 2.1 OK as long as the cam stays the same. Actual
figures on improvement hedged at.
European Racing, Eurorace, Red Lion, these people got lots of names
are no longer in the mags but are still oddly in business. They too say
96mm is the way to go, heck George here says you can even run 103's
for 2.4 with the FI as long as the cam did not change, stupid
admittedly as
you would run out of air majorly. Apparently the limiting factor in
their opinion
is that an agressive cam causes too much pulsation of the intake
manifold
causing erratic swinging of the air flow flapper. They still can get
forged
piston 96mm sets but OOOOF, $550 a pop. To stroke a 94's they used to
offer stroker short rods, do not now, and he gives me song and dance
about needing special pistons to change pin height $$$. I figure why
not just turn a little off the face but keep this to myself. I also
start
wondering why not a cam with slighly more lift but the same overlap
characteristics?
FAT performance. These guys are impressive know their stuff but
you pay for it. He can send dyno data of exactly what I can reasonably
take it to. They combine moderate head work, 76mm stroke using
spacers and turned down pistons (go figure), and 96 mm jugs for
2.2 liters and a gain of 18-20 hp and as usual cam must stay. Sounds
great but they wany $4500 to do it all. Still confirms my idea about
taking
some off the face of the piston. Also confirms that 100 real honest to
goodness hp is probably about the ultimate limit for a FI T4.
Bergman is the only cheap source for cranks, but we have Bob's
warnings on their crank quality and now on Bernies attitude in general.
I spoke with Bernie, he said my cranks are "very nice". $350 will get
you a 74 or 76 stroke from him counterweighted with 2.0 journals.
Oddball idea here, factory 2nd oversize is 95mm, seems an ideal size
more reliable than 96mm and with a 74mm crank good for 2.1. Nets
you 2013 with the stock stroke but sort of bet these have not existed
for a long time.
One final bit, some conjecture that the solid lifter cam although
having about the same lift and duration has a slightly more agressive
profile. Some say don't use it with hydraulic lifters but then again
a lot say to replace your solid lifters in car without ever splitting
the case so I figure its OK if there is any truth. I have good 1.7 and
2.0 solid lifter cams if this is a better idea, I seek opinions here.
Anyway against better judgement I'm thinking of doing the following.
I'm having Stephens rebuild the heads and letting them do a "port and
polish" but keeping stock valves. I'm going to opt for Bernie's crank
if upon inspection it seems too bad I'll send it back. I'll mic it
carefully
run it between centers and visually inspect the surface and dye-pen
it about all I can do to inspect the weld quality. I'm probably going
for the 76mm running .060 spacers and having 1 mm knocked off the face
of the pistons. Should keep me under 8:1 and give me enough clearance.
Any suggestion appreciated. Initially I'll build her up with the best
set
of used P&Cs out of my 3 current cores and new rings i figure as I don't
want to have brand new spanking pistons modified before I know it is
all happy. Such are my intentions, sucess would be the ability to climb
most of I68 through WV and MD in 4th without falling below 60 mph and
without the engine pinging on mid grade gas or overheating on long
grades. We'll see how it goes.
John
vwbus@tcpbbs.com