XN6 Performance

Joe Grubbs (jsgrubbs@ipass.net)
Thu, 01 May 1997 02:20:41 -0400

Hey everybody! I have a 1984 505 STI with the venerable XN6 motor
and ZF 3 speed auto trans. Despite the insulting remarks I hear from
some of you regarding stock XN6 performance, I find it quite acceptable
and I think it actually compares favorably to any new four cylinder
powered car today. The fact that an eight valve OHV 1971cc four banger
can push a 3000+ lb not-so-aerodynamic car as fast as it does is
amazing. I am interested in doing some performance mods however. I
found that the stock motor pulls hardest between 3500 and 4000 RPM. I
have removed the stock exhaust starting at the O2 sensor back. I have a
glasspack muffler in place of the cat and resonator and a Monza
glasspacked exhaust tip in place of the rear muffler. The car now pulls
hard from 3000 to 6000 RPM and makes a beautiful sound doing so, though
6000 RPM at full throttle is a bit noisy. The noise is well worth it,
though. With a good O2 sensor and no cat, the emissions are well
within limits and they are still lower than some cat equipped cars.
I'm thinking of installing an 80mm air flow sensor unit from a late 70s
VW (My XN6 has a 60mm unit). I also would like to know about those
"rising-rate" fuel pressure regulators. Do they really work and will
one fit on my car. Are there any REAL exhaust kits out there for my
car? Any other suggestions regarding "bolt-on" performance would be
appreciated. Hey... Peugeot Power baby!

Thanks,
Joe

P.S. My friend has a 1988 505 Turbo S. When we race at a stop light,
who do you think wins? Uh...Okay, he does. But who can you hear half a
mile away? Just make a wild guess!