Old Library

I had the 268's in my Corrado VR6, then I added the
schrick VGi, then I pulled the 268's in favor of the
DSR's, then I pulled the VGI, so I can give you a
little synopsis...

The 268's with the factory manifold felt pretty good. 
Sorta soft low end until 3500 rpm or so, then things
really got going at 4000 and pulled strong thru the
redline.

The VGi gave a huge lump of torque from 3-4000 rpm,
but there's a sharp drop off in power and torque at
4000 rpm.  Then the 268's will pick up again and go. 
Extreme top end is slightly better as the VGI has a
minimal power gain up top vs the stock manifold.

The VGi and the DSR's wasn't the greatest combo IMO. 
While I gained more low end, it was hard to discern it
due to the VGI kick over point.  And I lost *alot* of
top end pull.  The DSR's are done a little over 6000
rpm.  The 268's will pull to 7000 pretty easily,
although they're on the downside of the power curve by
that point too.

The DSR's with the stock manifold felt really nice. 
Strong all over, pulled well.  Works well with forced
induction, although if that's the route you're taking,
you really ought to stick with the stock cams...

I didn't feel the VGi gains were anywhere near the
cost of the VGi.  Once I put the stock manifold back
on I was surprised to actually prefer the feel of the
stock manifold!  It's much more linear and easier to
predict vs the VGI build power, big lump of torque,
sharp dropoff, build power again.  

-josh

Hi all -

Sorry for the delay in following up, but I hope "better late than never." ;)

(1) As for the choice between 268s and others (e.g. 260/264, 256):  I didn't
find the 268s to be worth it, on my otherwise fairly-stock car.  Perhaps
they're worth it if you have some serious head work done (porting, big
valves) but if you don't, they definitely AREN'T worth it.  Sure, they move
the peak power up in the rev range, but they don't make any more power.
That's right, I saw less than 2HP more peak power with the 268s compared to
the stock cams.  Sure, that peak was up a few hundred RPM higher in the
band, but it didn't make any more power.  To me, that's a waste of money and
only reduces driveability.  Shift a little earlier with the stock cams, and
you'll be going just as fast.  Maybe it's fun to wind out the motor more,
but if it's only for the noise and doesn't make the car go faster, it's not
worth it IMO.  (See http://www.p-vector.com/bob/garage/vw/cams-dyno/ for
details and dyno plots.  Note that I wrote that up before I decided to ditch
the cams.)

I've heard that the 268s *do* work better if you've had other work done, but
I know from personal experience that if you *only* do cams (and springs)
then the 268s aren't worth it.  Factor in the "exploding" valve springs
(which happened on my car too), and for my tastes, the 268s definitely
aren't worth it.

(2) As for doing it yourself: Tom (Fiction) is right in that doing cams
isn't too bad.  But if you *do* go for cams which require new springs, that
makes it considerably more involved.  You'll need a valve spring compressor,
a tool to remove the keepers, and (most importantly!) a way to keep the
valves from falling down into the cylinders while the springs are being
replaced.  Tom Doblmaier and I did it on my car, but it took a whole weekend
(two 14-hour days) to do it.  That's from two fairly intelligent humans who
had never done the job before.  I'm certain that with experience that time
would come down considerably, but for the first time, count on spending an
entire weekend.  However if you just do the cams (no springs) then it's
quite a bit easier.

Good luck,
- Bob T.
  '96 GTI VR6 179k miles - back to stock cams and loving it

268s work well on larger displacement motors with ported head and such but
I've found them to make little more than 264/260s which do not require
springs.


Best regards,

Joshua Murray
Matrix Engineering
4060 SW Macadam Ave.
Portland, OR 97201
503.443.1141 Tech
503.443.1142 Fax
888.249.0013 Orders
joshua@matrixengineering.cc
www.matrixengineering.cc

One possibility as to the different stories: the 268s *felt* faster, since
you could wind the motor out more without it running out of breath.  However
the "butt-dyno" and the real dyno didn't agree on the numbers.  I tend to
believe the real dyno more. ;)

Plus, Sondra and I in our younger days did a few "informal tests" between
our cars (her stock '98, and my cammed '96).  Basically they were dead even,
up to nearly triple-digit speeds.

If anyone else has dyno plots showing gains with 268s without any other
internal engine work, I'd be interested in seeing them.

Cheers,
- Bob T.

I saw little to no gain with a ported head on my VR6. 
My results were also mirrored by my friend, who also
saw little to no gain.  IMO, porting a VR6 head is a
waste of money.  All the power is gained by the bigger
valves.  However, why spend almost $2000, plus parts
and labor to install a big valve head to get 15-20 hp
when you can get the AMS blower kit for a bit more and
have 100 more hp?

I found the 268's to give *much* more power from
6000-7000 rpm, but at that point you're still past
peak hp and torque, so there's little point in revving
out that far.  While I noticed a huge drop in high end
power when switching to the 256 cams from the 268's,
the 256's were much more stout over a broader band,
which is used more often in street driving.

-josh