turbo back exhuast or down pipe back?
 

Hello,

Im fixing to bite the bullet and do upgrades, tuner, exhuast, intake, and EGR delete. Was wondering about turbo back or downpipe back and how hard is it to remove the stock down pipe. I read on here that you have to cut the factory down pipe to get it out.

O and 4" or 5" exhuast?

thanks

If your ever going to have to return to stock for inspection/emmissions reasons, I would just do a delete pipe....If not then turbo back.

I agree. Unless you intend to drag race I think you will find that removing the DOC back and adding any tune or even a stock tune will give you plenty of new found power.

A number of people on this forum have reported problems with after market air filters and knowledgable diesel guys say unless you're adding 200 or more HP the stock filter is plenty adaquate.

Plus, once you cut the down pipe it's over. No going back without pulling the engine or finding an extremely talanted welder.

IMO, down pipe back 5".

I did turbo back and went 4" out the back. I wish I'd have just done 5" and left the down pipe stock. The down pipe was a nightmare, it's not a 1 man job and it's certainly not this man and his wife job. I've been married 20+ years and heard my wife say words I am unsure sailors know.

This is good information! I will be ordering a mini maxx and down pipe back exhaust soon as my warranty just ran out. I am not sure if I want to go with 4 or 5 inch.
FivePointo -why do you wish you had went with 5" instead of the 4"?

Let's think about it a minute. The purpose of the larger exhaust is to allow more exhaust (air) to exit the turbo. If the down pipe is 3.5 inches, which I think it is, then what would a larger pipe behind that do for you. Other than looking more robust at the end of the tail pipe it can't do anything. It is down stream from the obstruction. But, I promise that when you start your truck for the first time after the tuner and delete you will be impressed with the power, even with a stock pipe.

No logic to me yea the stock unit is 3 1/2 in

I've got news for everyone. The OD may be 3.5" but the ID is far from it. I'm not gonna say whether or not you should do turbo back, but I'll be you will after this:


<a href="http://s68.photobucket.com/albums/i34/westwoodlands/?action=view&current=AD5358B9-AC3C-4352-9B57-3A9F3A6BDFAF-1006-00000068E13B9887.jpg" target="_blank"><img src="http://i68.photobucket.com/albums/i34/westwoodlands/AD5358B9-AC3C-4352-9B57-3A9F3A6BDFAF-1006-00000068E13B9887.jpg" border="0" alt="Photobucket Pictures, Images and Photos" /></a>

What is the sq inches of area in that cross section vs a 3-1/2 or 4" round pipe?

Stock: 7.36"
3.5: 9.62"
4: 12.57"

5" is 19.63"

So with that stock down pipe, you're really restricting airflow. The cold side CAC pipe is similar in its restriction.

I hope that math isn't based on that picture above. So what is the ID on a stock pipe? I can tell you I have plenty of power with the stock exhaust (absent the DOC/DPF). But if you want to drag race it then I guess changing the turbo back and the air box would help. Me, I'm just towing my trailer at 60MPH and I have more than enough power for that.

My math is calculated by imputing the image into AutoCad, tracing the image, scaling it based on the narrowest measurement that i took and the asking the software to calculate the area.

I can also tell you that power wasn't noticeable whatsoever. It was the EGT's that really improved after the DP was installed. With just a delete pipe, I could defuel at 1450 pretty easily. After a turbo back system, I rarely reach 1200 now before defueling because of boost PSI.