Now that I have my Thorley's waiting to get installed, I have been thinking about the rest of my exhaust. Does anyone have any reccomendations? I am going to get a custom y-pipe made w/o cats, but I am unsure about the size of the pipe. The Thorley's have a 2.5" collector on them. Here is what I have been thinking...please let me know what you think is best.

1. 2.5" y-pipe w/o cats to a 3" collector, followed by a cutout,then to a PV muffler.

2. 2.5" to 3" expanders, 3" y-pipe to a 3.5" collector, followed by a 3.5" cutout, to a 3.5" muffler.

3. 2.5" true duels with an x-pipe, followed by two 2.5" mufflers.

4 2.5" to 3" expanders, 3" true duels with an x-pipe, followed by two 3" mufflers.

This is a Whipplecharged truck with 6psi at the moment. I plan on getting water injection once the exhaust goes on and upping the boost to about 8-9psi.

Kent

<small>[ March 08, 2003, 09:03 PM: Message edited by: 1999stepside ]</small>

 

I'd say that #4 would give you the best performance for the whipple, but its also the most expensive and labor intensive option.

 

I also vote for the true duals but I am also partial to that exhaust. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> I dont know if you need the 3" though. Mine is 2.5" and I feel that I have a lot of room for expansion in the flow of the motor. Dual 2.5" pipes flow about 19% more that a single 3". But if you eventually add a cam and up the boost some more, you may want the dual 3".

 

i have number #4 <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> , i like it alot and would probably do it again.

soemthing to think about though, some cut outs would probably be faster, you could then put a quiet muffler on there and be quiet most of the time, single exhaust would be lighter too.

i still like #4 the best.

 

I'd have to agree with the rest of the posts. You're gonna need that 3" exhaust with the Whipple.