I couldn't decide on an exhaust, and a friend of mine with an exhaust shop said he would straight pipe my pickup for $50. I went ahead and did it. I figured for $50 if I didn't like the results it was no big loss.


Here's what I saw on the pyro.


STOCK STRIAGHT


65 mph on flat ground 750 690


65 mph up 6% grade 900 840


What are you guys with a full 4" seeing at 65 mph on flat ground? Just wondering what my $50 bought me. http://www.dieselplace.com/forum/smileys/Approve.gif

50 bucks for 60 degree cut, worth it if you ask me.

I tried it but too loud for me. Went with Banks Monster exhaust. Have not checked any temps. yet.Edited by: rpbdawg

Actually, I don't find it to be too loud. It's quieter than most gassers with glass packs. It's definitely not as loud as a Cummins. If it was that loud I wouldn't have done it.

I agree about the glass packs and the Cummins but I just like the sound with the muffler better. I did not mean to sound negative but was definitely quieter than I thought it would be.http://www.dieselplace.com/forum/smileys/Approve.gif

Good EGT data -- thanks!


I was disappointed in how quiet it is. That being said, I haven't pulled anything heavy yet...


No boom or drone -- I think you'd be hard pressed to find an aftermarket exhaust that sounds as good under a variety of circumstances. Personally, a larger diameter straight pipe is the only upgrade I am considering.


Did you notice a power increase? I am guessing that the straight pipe is worth nearly 20 hp (unlike the AFE which does nothing except sound good IMO).

Yes, I did notice a power increase, it seems to wind up quicker. It's hard to say how much, but I agree, it's good for a few hp. http://www.dieselplace.com/forum/smileys/Big Smile.gif


rpbdawg, I didn't take it as being negative. http://www.dieselplace.com/forum/smileys/Approve.gif

I noticed with my 6.5TD when I straight piped it 4" it spooled up much quicker and had lower EGTs. Also when cruising down the highway I would pull about 2-4psi more than with the stock system. My fuel mileage also went up. When I pegged it I would see a quick instant of 14psi and it would settle back down. With the stock system it would never go over 10 psi. I am still not sure what to go with for my Duramax. I don't want any drone. I don't want something quite that loud again. It didn't seem that loud in the truck but my brother drove the truck one day and I could hear him a mile and a half away.

Yesiree! I had it done today and damn, what a difference in the soundhttp://www.dieselplace.com/forum/smileys/Big Smile.gif I use to drive down the street and everything was quiet, birds were singing and people walking. Now I feel like I'm in Sturgis, birds jet from their nests and people take a few steps more to the curbhttp://www.dieselplace.com/forum/smileys/Evil Smile.gif I love it.

I checked my EGTS on 5mile strech of hwy back and forth to work relatively flat in cruise at 60mph (speed limit 55) ( Ohio HWY Patrol won't give much more than 5mph) Any way EGTS 525-575 with 4" Monster exhaust running empty..http://www.dieselplace.com/forum/smileys/Big Smile.gifhttp://www.dieselplace.com/forum/smileys/Geek.gif

EGT are between 550- 650 @ 70mph, sound is great not to loud. Very happy with system.( 4" monster)

I'm surprised the EGT's are that much lower on a muffled 4" than a straight piped 3.5". Nice data!

Welcome to a world of lower EGT's and LOWER HP.


I did a dyno comparison before and after my straight pipe and the truck consistently lost 5hp accross the entire power band. http://www.dieselplace.com/forum/smileys/Angry.gif


The feel of more power is due to the increased noise level. Do you self a favor and put the muffler back in.http://www.dieselplace.com/forum/smileys/Confused.gif


And yes I did 4 before and 4 after pulls to make sure there was no doubt.

These trucks make enough power that I wouldn't worry too much about losing only 5 HP. If you like the sound then it seems worth a measley 5 HP loss.

...Not to mention the EGT benefit as well.

I think that is BS. I know my 6.5TD definately had more power towing. I could hold OD on hills I could not before straight piping. A diesel needs to breathe. I would believe this on a gas because everything is tuned and timed but a diesel just wants more air and fuel.

Could it be that the power increase I think I have is actually coming from the turbo spooling up faster?http://www.dieselplace.com/forum/smileys/Confused.gif

Coughlin,


Your 6.5TD may well have picked up power, but yoru Duramax will not.


I think BS is what some people shove arround without factual data, care to share yours?http://www.dieselplace.com/forum/smileys/Confused.gif


I got my dyno pulls to back up before and after, not to mention after that. Believe it or not I dont carehttp://www.dieselplace.com/forum/smileys/Cool.gif