I know this has been an on going debate.

Just wanted some first hand experience about full length headers and performance exhaust for towing.

This is going into a 2002 Suburban 6.0L 2500 series.

Will full length headers and better open exhaust hurt or improve towing
performance?

Gas mileage?

 

I dont tow but I do have a suv with headers and with my experience I think I lost a tad bit of low end power with the headers. With the headers and my choice of running open Y it feels like the powerband has shifted up more, thus loosing low end grunt. But, you can use the headers and with a good gear combo (4.10s) youd probably make up for any loss in low end power.

 

With my truck putting the exhaust made a noticable difference in low end. When I added the headers I feel no difference and my MPG is the same.

 

so are you saying that you felt that there was more low power gained with the new exhaust over the factory exhaust?

 

It is my understanding that with a stock or fairly mild cam, in a fairly stock or mild engine;
If the header primary tube diameter size is (too) large (1 7/8", 2"), you will/may lose low end torque due to the loss of backpressure but, should gain on the top end of the RPM range. If the primary tube diameter is kept small (1 5/8", 1 3/4") or so then you should retain or even gain low end torque.
For a 6.0 displacement engine, I would think that 1 5/8" would be too small, 1 3/4" would be about right and 1 7/8" or better would work for a higher RPM powerband application.

 

Running an open y on an almost bone stock engine, will cause you to lose low-end power. Headers or not. @OP, do a fitting exhaust system to your specs and you'll appreciate the difference.