Camshaft Design
The camshaft plays an important role in the SportTuning of your water-cooled
VW. The correct application of camshaft design will ensure a proper
balance between drivability and performance.
Race cams normally have rough idling characteristics due to the large overlap
required for high rpm power. Street cams generally use a short duration and keep the lobe centers
spread apart to prevent too much overlap. Too much overlap on fuel
injected cars equipped with Lambda is especially bad. This can cause the
airflow sensor to buffet up and down, forcing the system to overcompensate in
either direction in an attempt to keep the CO in check.
Diagram #1 explains what happens to the fuel mixture when cam overlap causes both
intake and exhaust valves to be open at the same time. Some of the mixture
introduced into the combustion chamber is lost out of the tailpipe when the overlap
is lengthy. The loss of partially burnt fuel increases hydrocarbon emissions
without generating the low-end power desired for the street. However, a
little overlap can help scavenge the mixture into the combusition chamber on
normally aspirated vehicles. This is where the correct technology plays an
important role in today's cam design.
The duration of a cam is measure in degrees of rotation on a circle when the
valve is opened off its seat. An example would be a cam having 225 degrees
of duration at .050". This is a portion of a 360 degree circle when the
valve is lifted at least .050 inches off its seat. The longer the duration,
the more chance of the intake and exhaust lobes both being open at the same time
(overlap).
Another factor affecting overlap is the distance between adjacent lobe
peaks. This is referred to as a lobe center. Simply stated, it is the
measurement of distance in degrees of rotation from the peak of the intake lobe
to the peak of the exhaust lobe. The closer the lobe centers are to one
another, the more overlap. Fuel injected Volkswagen cams run best on 110
to 115 degree lobe centers. Racing cams are on the other end of the spectrum
and run as close as 102 degree lobe centers, creating very rough idling characteristics.
The base circle of a cam is the diameter of the heel dimension. Base
circles on cams may vary  depending on certain design features in the cylinder head. Such things as valve stem
length, valve seat height (how far down the seats are set in the combustion chamber),
grind on the valves and seats, thickness of the lifter/cam follower, location of the
bore in the cam towers, and the basic dimensions of the cylinder head casting
are all factors. The base circle diameter of a factory solid lifter cam is between
1.496 and 1.500 inches. On the hydraulic lifter cam the base circle is between
1.331 and 1.336 inches. The top of the hydraulic lifter is approximately .0825
inches closer to the cam centerline than the solid lifter.
A smaller base circle can change the valve train dynamics during running. If a
cam, such as a regrind, has a reduced base circle, the cam profile becomes more
sharply pointed. This can lead to harsh opening and closing of the valve, and may
even cause the lifter to skip off the cam surface during high rpm conditions. High
wear or harmonic valve spring failure may result from these problems.
A quick and easy way to measure the lift of a short profile cam is to subtract
the measurement of the base circle (B) from the measurement of the lobe height
(A) using a set of vernier or dial calipers.
An example: (Line A) 1.919"
 minus (Line B) 1.496"
Cam Lift =0.423"
Both intake and exhaust profiles should be checked because there may be a
difference in the lift and duration of each respective lobe (referred to as an
asymmetric cam). This "quick" method of measurement is not always accurate on
racing cams. Long durations can cause inaccurate measurements at the narrowest
point of lobe. In this case, the only accurate means of measurement is by using
a dial indicator and a set of "V" blocks for rotating the cam, or a computerized
cam measurement device.
Perhaps the most important thing to remember when searching for that "perfect
camshaft" is this: Don't be mislead by the numbers! The lift
and duration of a camshaft are not the only features that make a cam behave the
way it does. Things like ramp profile, lobe center, and nose shape all affect a
cam's behavior. It is virtually impossible to determine exactly how a cam will
perform, or where it makes power, just by looking at the numbers. Ultimately, all of
a camshaft's design aspects play a role in how it will perform.
8V Camshafts - Solid Lifter
From 1975 to the middle of 1980, the specs of the original cam were 0.405
inches lift with 225 degrees duration at .050" check clearance. On later cars,
including the Rabbit GTI and Jetta GLI models, the cams were made more docile for
pollution control and had a lift of only 0.387 inches, with slightly less duration than earlier.
Autotech Sport 286° Solid Lifter Camshaft
The last word in performance solid lifter cams. This cam runs strong after
3000 rpm and peaks at 6800 rpm, netting a 13 horsepower gain. The profile is 11.2mm
lift with a 286 degree duration measured (the European way) at 0.1mm check
clearance. Translated, this is 0.436 inches lift and 243 degrees of duration at
0.050" check clearance. The AUTOTECH Sport 286° solid lifter cam works best on
injected cars that are already extensively modified. This cam requires the use of SportTuned Valve
Springs. Lifetime warranty.
Description |
Part Number |
Price |
Online Purchase |
AUTOTECH Sport 286° Solid Lifter Camshaft
|
10.109.01.102 |
$159.95 |
Add to Basket |
Note: High lift camshafts can create unique problems in VW solid lifter
cylinderheads. The standard valve stem seal can be struck by the upper valve
spring retainer at lifts higher than .430 inches. We recommend using the
shorter Teflon seals. On cams with a lift of greater than .430 inches the
standard valve springs may bind on solid lifter heads. It is generally
recommended that you install sport valve springs when using cams with greater than
.430 inches of lift. Be aware that when using cams with greater than .430
inches of lift on some solid lifter heads, it may become necessary to clearance grind
each side of the lifter bores to prevent camshaft interference with the cylinder
head casting. This requires removal of the head.
8V Camshafts - Hydraulic
Hydraulic lifters eliminate the need for valve lash adjustment, not only making
maintenance easier, but making it much simpler to change camshafts as well. In
addition, hydro heads have a greater capacity for cam lift without head or
valvetrain modifications.
All of our hydraulic lifter 8V camshafts are 50 state legal under C.A.R.B. E.O. #D-375-1.
Autotech Sport 270° Hydro Camshaft
What we feel is the finest sport hydraulic lifter camshaft available.
Extensive experience with the VW engine design as well as consistent engine
dynamometer testing has resulted in a camshaft that is without question the
smoothest, most drivable performance cam you can buy. This cam allows the VW
enthusiast to enjoy the benefits of a substantial power increase with no
sacrifice in drivability.
The AUTOTECH 270° Hydro is the best performing street legal camshaft
available. Its idle characteristics have been refined to the point that it idles as
if it were a stock cam (15 inches vacuum @ 900rpm). Yet, its full-range power lets
you know that it is definitely not stock! Torque increases over stock appear as low
as 2500 rpm, continuing without fail until over 6000 rpm. Power gains range from 7 to
9 horsepower depending on vehicle and its state of tune. The AUTOTECH Sport
270° Hydro Cam is ground on an OEM chill-hardened billet. SportTuned
Valve Springs are not required, but are highly recommended for the best
top-end performance. Fits all 1.8L and 2.0L liter engines up to 1995 with
hydraulic lifters, including crossflow heads. Lifetime warranty.
Lift: 0.449"
Duration: 270° at 0.1mm check, 112° lobe center.
Description |
Part Number |
Price |
Order Online |
AUTOTECH Sport 270° Hydro Camshaft, through 1995 |
10.109.01.109 |
$159.95 |
Add to Basket |
Autotech Sport 260° Hydro Camshaft
This sport hydraulic lifter camshaft was originally developed for use in
Volkswagen G60 engines. The unique demands of a forced-induction engine require a
special cam design to fully optimize power gains. Shorter duration with less overlap
are key features in getting the biggest charge possible into the combustion
chamber. Too much overlap will result in "wasted" intake air, literally running
through the motor without being used. This cam is also suitable for use in Mk3 2.0L
cars, as it is does not usually require updating the valve springs, or remapping
of the car's ECU to run well. This camshaft will provide gains of
approximately 10 horsepower on a G60 engine. The Autotech 260° Hydro Cam is
ground on an OEM chill hardened billet. SportTuned
Valve Springs are not required for every application but are highly
recommended for the best top-end performance. Fits all 1.8L and 2.0L liter
engines with hydraulic lifters, including crossflow heads. Lifetime
warranty.
Asymmetric Lift: 0.421" Intake & 0.409" Exhaust
Duration: 260°/256° on 111° lobe center.
Description |
Part Number |
Price |
Order Online |
AUTOTECH Sport 260° Hydro Camshaft |
10.109.420 |
$159.95 |
Add to Basket |
16V Camshafts
Autotech Sport 16V Camshaft Set
Exempt under C.A.R.B. Executive Order D-375-4.
Ground on Autotech's own, custom manufactured, chill-hardened billets, our
Sport 16V camshafts achieve power levels higher than the benchmark Schrick 260 with
far better low-end torque and drivability. Great idle characteristics with 8 more
peak HP and up to 12 more ft.lbs. of torque than the 260's. Dynojet®
chassis dyno tests showed a gain average of 17.2 HP at the wheels over stock US
cams between 5000 and 6750 rpm on a GTI 2.0L. Without question, the best street-legal performance cams for your 16V. SportTuned Valve Springs recommended
for the best top-end performance. Lifetime warranty.
Intake 10.2mm x 252°
Exhaust 10.9mm x 264°
114° lobe center
Description |
Part Number |
Price |
Order Online |
Autotech Sport 16V Cam Set |
10.109.418K |
$349.95 |
Add to Basket |
12V VR6 Camshafts
Autotech Sport 262° 12V VR6 Camshaft Set
 
Autotech is pleased to offer 262° cams for the 12V VR6 engine. These are
fantastic performing cams, providing fat mid-range power and a strong top end
without sacrificing bottom-end torque or smooth idle characteristics. Dyno tests on
a 1998 GTI showed an increase of 8.3 peak whp over stock, while moving the power
peak up from 6100 rpm to 6300 rpm. Cam set includes our slick cam alignment tool. SportTuned Valve Springs recommended for the best top-end performance. Lifetime warranty.
Lift: 11.2mm (0.440")
Duration: 262° on 115° lobe center
Description |
Part Number |
Price |
Order Online |
Autotech Sport 262° 12V VR6 Camshaft Set |
10.109.460K |
$309.95 |
Add to Basket |
Cam Alignment Tool only (comes with above camshaft set) |
10.012.460K |
19.95 |
Add to Basket |
1.8T Intake Camshaft
Autotech Sport 195 ° 20V 1.8T Intake Camshaft
After many months of testing Autotech is pleased to indtroduce the 1.8T intake camshaft. This is an excellent addition to any 1.8T whether it has a software flash or not. Autotech dyno'd gains of 10hp and a torque increase of 7 ft. lbs, on cars without a software flash. Cars with a flash experienced a 4 hp gain and a torque increase of a wopping 12ft. lbs. Lifetime warranty.
Lift: 7.85mm (0.309")
Duration: 195 ° at 0.050" lift
Description |
Part Number |
Price |
Order Online |
Autotech Sport 195 ° 1.8T 20V Intake Camshaft |
10.109.480 |
$299.95 |
Add to Basket |
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