Re: I-5 10v NA power? (Bruce Bell reprint)

[MHLIGGINS@aol.com]

	After seeing some of the comments on this thread, I've begun searching
through the files I've saved. Found this one from Bruce Bell.  I also think I
kept one by Ned Ritchie, but haven't found it yet. If I do it'll be posted.
:-)

	Later.
	--ml


<<Schrick 272 camshaft review - Updated (long)

From: "Bruce Bell" <bbell04@ibm.net>
Subject: Schrick 272 camshaft review - Updated (long)
Date: Tue, 29 Sep 1998 19:01:27 -0600

[ There were a couple of recent requests for information on the Schrick and
I sent out my review from 1995 without realizing it needed to be corrected,
At the time I wrote the review my car had, unknown to me at the time, a
failing temperature sensor which adversely affected the cars performance. ]

[ All the new text will be included in square brackets ]

[ From Jan 4, 1995 ]
Review
Schrick 272 deg. Cam in an '87 4000 CS Quattro. Applications: all Hydraulic
lifter Audi's and VW's both 4&5 cylinder.

Summary:
Prior to installing the cam my performance expectations were moderate. I had
no delusions about turning my car into an S4 eater with gobs of torque. Cams
just don't work that way. Performance cams don't make more torque, they
primarily define where (in the rpm range) the torque is available. My
expectations for this cam, were to give up some bottom end torque in
exchange for more power at higher rpms. I expected idle to be considerably
rougher. What I got was a much smoother idle than anticipated. Up to around
2500 rpm there is definitely a softer feel. From 2500 through 4500 rpm it is
almost impossible to tell the difference from stock. At 4500 rpm where power
used to start fading away into the sunset, there is the slight sensation of
a surge while the engine pulls with authority all the way to redline at 6300
rpm.

One surprise with this cam is how the exhaust note changed! It sounds like
the car is gurgling with pleasure, all in all a pleasant and unobtrusive
sound. . [As the temperature sensor got worse, and the car started running
richer, the gurgling became early morning coughing and sputtering] My
recommendation? If you drive spirited and want to spend the money go for it.
If your style is to shift at 2500-3000 rpm, then save your money unless you
just want the cool sound.

Background:
Last October I suffered the indignity of breaking my timing belt. With the
car in the garage and rental tools in hand I began the chore at hand.. I'm
generally a little impulsive and heck the valve cover and cam gear were
already off the car so, credit card in hand I called Ron's Parts in
Vancouver, BC and ordered a Schrick 268 deg cam for my car. I've known about
Schrick cams for some time. Most notably from the hydraulic camshaft
comparison test tectonics and "VW&Porsche" (EC) reported on in April, 1988.
According to the article, "[the 268] is best for a street cam because the
superb torque characteristics are accompanied by a stock smooth idle".  This
was the cam for me.  The cam arrived and, behold, it wasn't the 268. I
called Ron and he said this an updated cam with 272 deg. on the intake and
268 deg on the exhaust side.  The cam has 110 deg. lobe centers with an
11.2mm lift. Valve timing is 26 and 66 degrees for the intake and 24 and 64
degrees for the exhaust. Valve overlap is 50 degrees. This cam uses the same
profile for both 5 and 4 cylinder motors.

Installation:
One of the benefits of a hydraulic lifter cam is ease of installation since
there are no lifters to adjust. Start with the #1 cam lobes up (i.e. both
valves closed) and follow Bentleys advice in removing and replacing the
bearing caps (sequence is important). With the Schrick all you need to do is
lubricate it with engine oil prior to starting the engine. Many Aftermarket
cams are regrinds or soft (softer)steel with a hardening on the exterior.
For them a god cam lube is considered essential. The Schrick on the other
hand is a chilled billet just like the OEM cam. If it makes you feel better
go ahead and use cam lube.

Driving Impressions:
Starting the car for the first time gave me the jitters, after all, what if
I did something stupid? Don't ask my wife. At first, all I heard were the
lifters in a cacophony of ticks and tacks; but as the oil pressure came up
and the idle settled down, I could hear the gentle thump of overlap in the
exhaust. Perhaps It's the extra cylinder; but the idle seemed smoother than
my Jetta was with the Euro GTI cam.

Time for a ride. I entered the street in first gear and listened while I
accelerated to 4000 rpm and shifted into 2nd gear. At 3500 to 4000 rpm I
began thinking about how to explain my frivolity to my wife when even I
couldn't feel the difference. I watched the tach as it climbed at almost a
linear rate through 5500, 6000 then redline. Ah I thought, vindication, this
will help me pass tourists in campers on two lane roads. In first and second
I found watching the tach was a worth while activity since for the first
time ever I experienced the fuel pump shutting down at 6500 rpm! In third It
will easily pull to 6500 but you have a little more time to shift.

In town, I tend to shift early, keeping engine rpm between 1800 and 3000.
This is where I feel the softness in low end performance the most. It still
pulls smoothly from 1200 rpm in 5th, but the lack of torque is noticeable
until close to 3000rpm. Lately I've noticed a tendency in me to drive in a
lower gear keeping the rpm in the 2500 to 3000 range. On the highway, for as
long as I can remember I got around 26-27 MPG. Now, It appears mileage has
dropped off to the 24-26 MPG
range. This is probably a combination of the cam and my new driving habits.
[It was the temp sensor - my gas mileage actually went up in highway driving
after changing the temp sensor. For the first time with the cam my car
actually delivered an honest 29 mpg though 27-28 was more typical]

On cold mornings starting is a little slower. I find using full accelerator
while turning the key works best. It then takes about a half mile to shake
out the cobs. I also notice more odor from the exhaust (gas) on cold
mornings. [This should have been a clue to me. All of these issues were
cleared up with the replacement temp sensor.

Performance by the numbers:
Several years ago, when I was building my Jetta, I came across a method for
computing road horsepower.  This method computes power based on the time it
takes to accelerate from one speed to the next. I modified this in my excel
spreadsheet so that I could simply enter the acceleration times from one rpm
to the next. In this case I did it in 500rpm increments using third gear.
the spread sheet then computes the speeds at the rpm and averages those into
road horsepower figures. Whether these numbers would compare to a chassis
dynamometer or not, I don't know. They do; however, provide a basis for
comparing performance changes.

As you consider these numbers and my comments above, keep in mind that I
live at 5300 feet in elevation. While I doubt the basic torque curve would
change very much, those of you at lover elevations should experience a
little better low performance due to volumetric efficiency. (my guess)

                 time         Horsepower       Torque
Rpm Range    Stock Schrick  Stock Schrick  Stock Schrick
1000-1500     1.90    2.22   16.6   14.2    69.7    59.6
1500-2000     1.74    1.95   25.4   22.6    76.1    67.9
2000-2500     1.70    1.83   33.4   31.0    77.9    72.3
2500-3000     1.67    1.72   41.5   40.3    79.3    77.0
3000-3500     1.67    1.67   49.1   49.1    79.3    79.3
3500-4000     1.67    1.67   56.6   56.6    79.3    79.3
4000-4500     1.67    1.65   64.2   64.9    79.3    80.2
4500-5000     1.71    1.65   70.0   72.6    77.4    80.2
5000-5500     1.79    1.66   73.9   79.7    73.9    79.7
5500-6000     2.25    1.71   64.4   84.8    58.8    77.4
6000-6500     3.42    2.00   46.1   78.8    38.7    66.2

I computed these torque figures using the standard (hp/rpm*5250).

By the way, I burned a considerable amount of gasoline to get these numbers.
Being consistent with a stopwatch while watching a tach and the road ahead
isn't easy. These numbers (times) are the results of many runs over many
days in sometimes wildly varying conditions. I can guarantee that vehicle
weight varied since sometimes I had a full tank and sometimes it was nearly
empty.  Hence, most of these times represent averages that I have confidence
in for future comparisons on my car.

The Future:
Well I believe only torque can make a man truly happy. Since the intake
valve doesn't close until 66 deg. ABDT there is less time for the
compression stroke and volumetric efficiency is a concern. So my next step
won't be to port & polish or trade in the 38mm valves for 40's. Those
changes would no doubt improve top end a little more; but I suspect they
would really hurt at the bottom. Next is at a minimum to increase the
compression to over 10:1 with a piston change. Hopefully I'll be able to
change the crank too. This, I think will also help cold weather starting.
[well, plans do change, little did I know then how much]

Disclaimer: I have nothing to do with Schrick or Ron's Parts other than
being a customer. A very satisfied customer.


Bruce Bell
bbell@surview.com>>