Exhaust Magic...

From: brian duffey (brian.duffey@intelsat.int)
Date: Mon Feb 22 1999 - 13:32:00 EST


O.K. All, I'll try to keep this brief… but unfortunately, this is not a
Yes/No question. There has been much talk lately about exhaust systems,
backpressure, HP gains & torque losses. I have been looking for a new
exhaust and have (had?) decided on the Gibson Single Cat-back (truck is a
'95/5.2L - Auto, 4x4,Ext Cab). I've seen a lot of comments that with a 2.5"
pipe (or larger), the loss of backpressure would result in decreased low-end
torque. Can anyone give some real world examples and/or suggestions?

I'll be adding the Mopar HiPo comp. at about the same time. Already have the
K&N open element FIPK and F&B Stage 1 TBI. Hopefully not too long after
those mods, I'll have the Leach Headers installed.

What is the diameter of the Leach Y-pipe going into the Cat? If I go with
the HiPo Comp, Gibson Cat-Back, Leach Header route will my result be just
top end gains, or can I expect to gain some low end? I really need to
increase my low end. Up about 1800-2000 RPM onwards my DAK starts to move &
runs great at highway speeds. What I need to gain is low end for 4x4 and
also quicker starts off the line. As an alternative route, would getting
just the Gibson muffler and having the pipes custom made at 2.25" be a
better approach for my goals? (I'd still get the Gibson Slash tip - 3" - for
the finishing touch!)

I understand the theory behind getting the airflow thru the engine exhaust,
but it seems like finding the right back-pressure/flow rate is kind of black
magic. Any comments from those experienced in the Dark Arts?

Thanks all & sorry for the long post!

Duff
'95 SLT 4x4 CC 318 4spd/OD - 3.55 LSD
MSD 6AL - MSD Blaster Coil
MSD 8.5 wires - K&N FIPK - F&B Stage I TBI



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