4" Exhaust upgrade

[gimpyhauler]

A friend was just telling me that his friend with an LBZ installed 4" exhaust tubes and 4" turbo tubes and now he claims to get 28MPG.

Really?

What am I really going to see in a real world difference in my truck if I step up to a 4" exhaust system? If I can increase my mileage 6-8 mpg then the cost of the new exhaust seems reasonable.

[rapidoxidationman]

My '05 Duramax is stock.

I get 25mpg in my diesel....



















Mercedes 300D.

(nope, I call BS on your buddy unless he has a propane system installed.

[gimpyhauler]

My '07 LB/CC with 85 gal transfer tank in the bed gets 18-20mpg on a good day at 55mph. On cruise control.

I want to know what going to a 4" exhaust system would do for me.

[DmaxMaverick]

I want to know what going to a 4" exhaust system would do for me.

Nothing, except on a good day, driving 55, on cruise control. Then, little if anything. Exhaust is only a small part of a big puzzle. But, it's a start.

[gimpyhauler]

If I don't plan on spending a few grand on all the parts of the puzzle, will the 4" exhaust be worth the effort? Or will I still have the same truck with new exhaust?

This truck has been the best vehicle I've ever owned and with 200K on the clock, it's still ticking like a Timex.

[EdHale]

I have 152,000 on my truck and it will get 19-20 mpg at 60'ish on cruise and nothing behind it. It gets 12 +/- .5 mpg towing a 35' 5th wheel RV also at 60'ish. It is bone stock and I'm not changing a thing.

[Kennedy]

The best bang for the buck is in the ECM programming which you already have.

[gimpyhauler]

Thanks all.

Especially for my ECM from Kennedy. I'm sticking with what I have.

PS: Also thanks again to Kennedy for getting me to put my stock airbox back on and get rid of the K&N. All problems solved.

[More Power]

I saw no measurable change in fuel economy after installing a complete 4" Magnaflow exhaust system in my 2001 LB7 GMC.

Now.... Lil Red, my 1/2-ton Duramax/Allison project produced 25-mpg for a tank of fuel once while traveling at 80-mph on the Interstate. But, it only weighs 5000-lbs has a lower drag profile. It also has 3.42 gearing. 80-mph produces 2000-rpm. So... I call BS on an LBZ getting 28...

[gimpyhauler]

Thanks Mr. Power,

That's really what I thought. But I had to ask. I just can't believe the mileage would go up that far with just adding a 4" exhaust "and Turbo" to the system.

I have numerous trailers from short to 38ft and a 32ft 5th wheel travel trailer. I have a backhoe pro trailer and have hauled my Case 580. I can't believe I could ask it to do more or any better. I am not unhappy with my rig and it has treated me better than any vehicle I have ever owned in over 60 years and I have asked more from any vehicle. I hope this is the last vehicle I ever have to own.

Thanks again my friend.