I'm confused and would be grateful for some input to unconfuse me. I want to replace my sock exhaust with a 4 inch system. Haven't decided which one yet but before I go froward I have a couple questions. I recently downloaded some instructions for the exhaust swap from this site. They include cutting the stock down pipe and cutting and folding back a body seam. I just took a good look at my truck (01 extended cab 4X4) and I don't see any need to cut a body seam. 1. Do I perhaps have instructions for the 6 liter truck or am I just not seeing something?? 2. Is cutting the down pipe needed because the cross member won't allow it to come down or is there another reason???? If it's a problem with the cross member will the new downpipe couple forward of the cross member??? And, wouldn't it be easier to cut the pipe under the truck????? Is there anything else I need to know????? Thanks in advance for any input

Stan Zzzzzzzzzzzz

 

I believe modifying the body seam only applies to pre-99 PSDs, the OBS, or older body syle.

 

I did a 4" turbo back on my '01 super cab and no issues on trimming or bending on the seam. It fits close, but it fits.
Cutting the stock downpipe out just makes it a hell of a lot easier to remove.
My Hog SS exhaust does couple in front of the x-member if that helps at all.
The only thing I would recommend is stick with a quality system. Less headaches and good fit are worth the little bit of extra $$$ you pay for it.
Problem I find is once the wallet opens, it never closes.lol
Hey, its only money and you can always make more!

Austin

 

Do yourself a favor and get the 5", better sound and no drone.

 

But doesn't the exhaust manifold on the engine going into the exhaust restrict down to 4" anyway? So what would be the value except for the sound?

 

Actually, if you look at the exhaust uppipes where they combine into the turbine housing, they are a LOT smaller than 4-inch. That is to create lots of high pressure for the high temperature gasses so the turbine can be driven.

The larger exhaust is only on the exhaust side of the turbine and is used to reduce backpressure that the turbine sees in order to reduce EGT, get more exhaust flow through the turbine, and let the turbine spin up better. Well, that doesn't take into account the turbine housing A/R ratio, but that is a subject for another thread.

The reality is, no one here has clamied any kind of performance advantage to a 5-inch pipe. If there is a lower EGT compared to a 4-inch, I wouldn't know about it because I went from stock to 5-inch. I doubt there is any significant difference between the the 4- or 5-inch with regards to function.

The advantages are partly aesthetic, mostly visceral. The look of the sewer-pipe sized cannon sticking out from under the truck is great. But not as great as the sound. Mine is quiet inside with the windows up. Sometimes it is quieter than stock, sometimes not quite as quiet. From outside, it rumbles far deeper than any 4-inch I've heard. It just sounds mean - especially if you are behind it when I'm on the throttle.

Seriously if all you are after is the pure functionality of opening up your exhaust and don't want to be extravagant for no functional purpose, save the $100 extra the 5-inch costs.

Me? I wouldn't consider changing down to a 4-inch. The sound alone is worth the meager price of admission.

But I can ONLY speak for myself.

 

2 questions come to mind. Do that make that for an 01 Excursion? Also what is the benifit since the outlet is about 4 in?

 

You may want to check. I think that I read something in this forum about a 5in would not go over the rear axle for the Excursion.