I'm a believer in cams and exhaust. For the longest time I thought they were
gimmicks. Turns out they do make a difference! I feared that modifying the
valvetrain would make the SR have an undriveable idle, and poor low-end
performance. I wasn't even expecting noticeable power gains.I was wrong! If
it's possible to fall in love with your roadster all over again, I'm doing
it!
Modifications:
JWT C1 prototype cams, modified to work with the S14 SR20's VTC
The C1 is the mildest racing cam with 264 degrees of duration and a lift of
0.476". We chose the C1 over the S4 cam for more power, driveability, and a
smooth idle. Well, at least that's what they advertised.
Also redid the exhaust from the manifold back using 2" diameter tubing,
retaining the Borla muffler. Old piping was stock sized 1-3/4".
Dyno/Results:
Baseline: 132.92hp/126.04tq
Cams/exhaust: 156.29hp/136.37tq
Dyno Sheet:
http://community.webshots.com/photo/193935266/2481516820058696712lnStKb
We gained 23+rwhp and actually GAINED 10lb-ft torque!!! With 15% drivetrain
loss that puts us at 180hp at the crank!!!!
We initially thought there would be a slight loss in low-end torque, but we
made 10+lb-ft more torque! This is can be attributed to the VTC doing it's
job.
Driving:
-No loss in driveability. It's much better with more useable torque down
low! Talk about "waking" it up, after 4k it really rips. Night/day
improvement.
-No lopey idle, though it does have a more pronounced burble at idle
-More torque, and it's apparent down low too! I can short shift at 3500rpm
and still accelerate briskly.
-Torque increase also evident on corner exit.need an LSD pretty bad now
though.
-The exhaust is noticeably louder between 2000-3200rpm, and it absolutely
shreaks above 4k onwards with the cams.very raw, very mean.
Some videos showing the difference in sound/idle and acceleration!
Stock Cams, 1-3/4" exhaust. Acceleration through 2nd gear
http://rabbit.circa.ufl.edu/albums/alvin/MOV06341.mpg
New cams, 2" exhaust. Acceleration through 2nd gear. Same location as above!
http://rabbit.circa.ufl.edu/albums/alvin/newcams.mpg
Old exhaust, revving.
http://rabbit.circa.ufl.edu/albums/alvin/oldexhaust.mpg
New 2" exhaust, revving:
http://rabbit.circa.ufl.edu/albums/alvin/newexhaust.mpg
New exhaust idling:
http://rabbit.circa.ufl.edu/albums/alvin/idlenew.mpg
I'll be taking her to the drag strip June 7 to see if I can do some mid/low
14's without re-learning how to launch.
Enjoy, and open up those exhausts on your R16s, SR20s, U20s and KA's :)
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