When we did dyno testing on my full-race Toyota engine we tested four exhaust
systems, all 2 1/4" diameter, and about 10 feet long from the header collector
to the open end of the pipe:
1. Straight pipe,
2. blue bottle straight through glass-pack,
3. Supertrapp with about a dozen plates (not the fancy 10 lb chrome-tipped
thing) and an endcap,
4. and a Thrush turbo muffler (400 or 500 series).
In order of annoying exhaust tone (worst first) we found:
1. Supertrapp (about 110 dBA, if my memory serves correctly)
2. Straight pipe (deafening at 112 dBA 30 feet behind the pipe, but not as
annoying as the SuperTrapp)
3. Blue Bottle (106 dBA and a lot more mellow than the straight pipe)
4. Turbo muffler (about 95 dBA)
Power:
1. Open pipe, 180 HP at 7500 rpm
2. Bottle, 178 HP at 7500 (basically no difference from the straight pipe)
3. Supertrapp, 165 HP at 7000, torque started to fall off above 6500
4. Turbo muffler, 160 HP at 6500, torque falls off above about 6000
On the assumption that exhaust flow and power output are proportional, a
dual-exhaust Tiger producing over 300 HP will be ill-served by Supertrapps or
regular Turbo mufflers. I have also run my race Toyota using a Flowmaster
muffler, and it seemed okay, not as loud as the glasspack, and it made decent
power, but I don't have dyno numbers for it, and I don't have track times using
one of the other exhausts on the same chassis as what I used the Flowmaster on.
My preference for when I have to replace the Mitchell mufflers that are on the
Tiger: 1. Bottle mufflers 2. Flowmasters 3. Turbo mufflers. If the bottle
mufflers are way too loud I'd have to go to the Flowmasters anyway. Under no
conditions would I shell out any money for Supertrapps.
Theo Smit
tsmit@novatel.ca
B382002705
> -----Original Message-----
> From: Mike Sutter [SMTP:mjsutter@cts.com]
> Sent: Friday, February 12, 1999 9:03 AM
> To: tigers@autox.team.net
> Subject: Mufflers
>
> Scott,
>
[] <snippage>
> Mike
|