Exhaust question
Rock Crawling
Joined: Dec 2010
Posts: 319
Likes: 1
From: Gaithersburg MD
You still forget one very important part. The valve train is engineered for a certain amount of "back pressure". If you take that away, you have to upgrade the valve train or you will have failure. This has nothing to do with emissions or noise levels.
As for 'shade tree' mechanics. I don't consider then bad. I am actually grateful for them. I find it reassuring to know that they keep me in a high paying job.
As for 'shade tree' mechanics. I don't consider then bad. I am actually grateful for them. I find it reassuring to know that they keep me in a high paying job.
Indeed Sir!
Also - pardon the pun, but the reasons I listed were not intended to be "exhaustive", simply an example of the reasons why, in my uneducated opinion, it was a bad idea to not have the exhaust as designed.
Last edited by groundandpound; Apr 28, 2011 at 04:20 PM.
So my exhaust is Swiss cheese. Pretty much from the cats back, at every flange it's rusted through. Some of the hangers are shot etc, it's in bad shape (sounds good though, haha). I already kicked off the resonator because it was removing itself. I'm up for inspection in July and I have a guy that'll pass me but my question is this. What am i incurring by running this essentially wide open exhaust system. Can I be messing up my mileage because there's not enough back pressure? Do I lose power as well if it's too wide open?
A couple of bends in a piece of straight pipe, a new muffler and you have a complete new exhaust and your truck can be as quiet or as loud as you want.
Just tell them the sound you are looking for, I wanted sniper quiet so thats the muffler I had installed, $100 out the door to have my old muffler taken out and the new welded in.
The rest of my exhaust is still good.
Winching
Joined: Jul 2010
Posts: 598
Likes: 12
From: Swampy Sandbar, USA
When the Germans bombed Pearl Harbour...
This was a good thread....
'No' back pressure, as the wise have said, is outside of the specific design parameters and blows (another pun for ya) performance-wise. I've seen a few different configurations with these engines and I particularly like the stock manifolds into "test pipes" (no cats), into a center muffler and straight out the back with no resonator. Really great low end pressure values for the ideal flow up to 2500 rpm and then good sound up high, from 3000 and up without too much of that skull bangin vibration you can get with hi-flo cats and headders straight out.
just another opinion...
'No' back pressure, as the wise have said, is outside of the specific design parameters and blows (another pun for ya) performance-wise. I've seen a few different configurations with these engines and I particularly like the stock manifolds into "test pipes" (no cats), into a center muffler and straight out the back with no resonator. Really great low end pressure values for the ideal flow up to 2500 rpm and then good sound up high, from 3000 and up without too much of that skull bangin vibration you can get with hi-flo cats and headders straight out.
just another opinion...
Rock Crawling
Joined: Aug 2010
Posts: 323
Likes: 10
C-
mainly because you got the lyric wrong
it's:
You got it buddy, the large print giveth
And the small print taketh away
it is splitting hairs, I know, but life's beauty lies in the minutiae
If you fix it in your signature I'll consider raising it to a C
ffwd to 4:31 if you require proof:
YouTube - Tom Waits - Step Right Up.
mainly because you got the lyric wrong
it's:
You got it buddy, the large print giveth
And the small print taketh away
it is splitting hairs, I know, but life's beauty lies in the minutiae
If you fix it in your signature I'll consider raising it to a C
ffwd to 4:31 if you require proof:
YouTube - Tom Waits - Step Right Up.
Thread Starter
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Recovery Vehicle
Joined: Feb 2010
Posts: 1,057
Likes: 23
From: Boston
This is awesome. I spent all night last night giving the disco a lift and I wake up to all these awesome (and super nerdy) posts. (geek, I'm a chemist and thermo was my least favorite class). The up shot is it certainly FEELS Like ive lost a bit of power. I'm definite going to replace the exhaust but If I can get inspected and passed to buy a little time that would be great. As much as I want to run test pipes I think (correct me if I'm wrong) PA requires cats and I don't think my friend will be doing my inspections for ever so it may be smart to throw cats in right? I'm thinking stock manifolds (not sure of the diameter of the manifolds but I'd like 2.5" pipe) to central muffler straight back but turned down somewhere near the rear wheels and terminated there. instead of out the back. Any reason why I shouldn't do that?
Winching
Joined: Jul 2010
Posts: 598
Likes: 12
From: Swampy Sandbar, USA
Only thing id suggest in not terminating the exhaust tip early. It really should exit away from the vehicle. One reason is just simply smell but also the hydrocarbons are pretty corrosive and you could end up with a bit of accelerated corrosion in that particular area...
Thread Starter
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Recovery Vehicle
Joined: Feb 2010
Posts: 1,057
Likes: 23
From: Boston
I appreciate the tip. Ill definitely take it under advisement. I have a picture on my phone of a guy who had a custom d1 rear bumper made where the exhaust terminated out the side of the back bumper. Very very cool. Wish I could up load it from my phone somehow.
Thread Starter
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Recovery Vehicle
Joined: Feb 2010
Posts: 1,057
Likes: 23
From: Boston
So here's an addendum to my exhaust issue question. I haven't been under it to ID all the holes in the exhaust but if I had one before or real close to the upstream o2 sensor do you think that could cause it to get a bad reading? Because I'm throwing the same code I did a hear ago when my driver upstream o2 sensor failed. I replaced it with an oem, but now it's says it's bad again. Only a year later. And if it can't be exhaust related, why am I killing the same o2 sensor all the time? (the only time my truck doesn't see high octane is when I lend it to a friend who fills it without asking what it takes)
