[s-cars] RS2 Upgrade Questions

[Rich Letsinger]

> > 3.     What changes should be done to the head
> > besides rebuilding? A new exhaust camshaft?
> 
> Since you have the head off, and if you have the
> $$$, then a RS2 exhaust cam will restore some of the
> lost bottom end.

I believe this is backwards.  From my understanding, a
"hotter" exhaust cam helps high RPM flow while
sacraficing low RPM efficiency.  So going with an RS2
cam (or a 7A cam for more of a change) will make more
power at the top end but will raise your boost
threshold and hurt low RPM torque.

I don't have any comparison numbers as I built my
engine with a 7A exhaust cam from the start.  But I
did some reading and talking to folks who know.  The
7A should have raised my full-boost threshold a couple
hundred RPM and raised my power 10 or 15 hp.  These
numbers are with an RS2 turbo.  With a bigger turbo
the effects will be greater and with a K24 the change
is probably negligible.

The other thing to keep in mind is that a "hotter" cam
will hurt your emmisions.  You'll be passing more
unburned fuel into your exhaust system.  If you've got
a cat this'll heat it up more and may even make you
fail emmisions.

Rich


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