2500HD Gas Mileage

**lewisb13** · 11-04-2009, 08:28 AM

So for those of you with the 6.0 who have an intake AND exhaust, what kind of calculated (not theoretical) gas mileage are you getting? Is it possible to get 17-18 mpg out of these trucks somehow?

**vncj96** · 11-04-2009, 08:37 AM

The old man can easily pull that on his 07 NNBS crew Z71 6.0, usually closer to 21, but for an HD might be harder, I would assume they have a 4.10 in the back for the towing.

**lewisb13** · 11-04-2009, 11:14 AM

Originally Posted by vncj96

The old man can easily pull that on his 07 NNBS crew Z71 6.0, usually closer to 21, but for an HD might be harder, I would assume they have a 4.10 in the back for the towing.

Yeah mine has the 4.10 in the back. Im just wondering if spending the $1000 on a full intake and exhaust is going to be worth it. I get about 12-14mpg right now and will not be spending the $1K unless I can securely get to 17-19ish.

**doczog** · 11-05-2009, 01:23 AM

If you are getting 12-14 mpg, you are doing about the best you can....

I get just about that and here is what I have done to mine...

Changed to 265x70x17 tires and wheels to reduce the 4.10 ration to about 3.90....lost performance and mpg....down to 10-11 mpg

Added K&N Filter system....no change for $235

Added Magnaflow catback with dual tail pipes....sounds great....no change in mpg...$425

Had a Blackbear tune for $350....got some performance back and mpg back to 13-14...

So, $1000+++ later, the truck sound great, runs good and still gets the same 12-14 mpg...

You have a 6000 pound truck with towing gears....12-14 is about all it will give....

The only HD that gets worse mpg is my son's 8.1 L 4x4....allmost gets 12 mpg on the hiway, and 8-9 around town...pulls like a diesel though....

**Land Shark** · 11-05-2009, 01:38 AM

You have a 2500 HD and expect to get gas mileage

I am lucky if I get 10. I knew what I was in store for when I did all the mods to mine. Its the nature of the beast.

**lewisb13** · 11-05-2009, 08:29 AM

Yeah Im cool with the gas mileage. Im just coming off of a 400hp turbo 4 banger that got 35mpg and dusted the piss out of any v8 on the road. Theres the obvious pump shock I think that everyone with the 2500HD went through. Im glad you guys posted your comments, it gives me some real good insight. Thanks for the help boys.

**vncj96** · 11-05-2009, 11:00 AM

Most likely you wont get that 17mpg plataeu but what helps is watchingyour RPMs, when accelerating try and keep the tach under 2000RPM and that will help a bit might get a gallon. As for the exhaust and intake, thats up to you everyone gets different results

**Bigcl** · 11-06-2009, 12:57 AM

15.6 mpg with my 2009. 3.73 gearing. When towing my 32' 5th wheel mpg goes down to 8-10. I'm able to maintain speed at around 55-60 on most hills with no more than a 5% grade. At 5% and greater speed drop to around 45mph...rpm around 3500 - 4000. So far so good. The 6.0L vortex is a great engine.

**lewisb13** · 11-06-2009, 09:43 AM

Wow so even with the better gearing the gas mileage isnt that much better. I seriously love this truck. I dont know if Ill take my car out of winter storage or not in the spring!

**doczog** · 11-09-2009, 08:32 AM

My neighbor just last month bought a 2009 GMC regular cab short bed with the 4.8 engine and that system that goes from 4 cylinders to 8 cylinders (forgot the name)...

Even with that light of a truck he get 19 mpg on the hiway....he is mad because the salesman said he would get over 22....he believed the salesman....oops.

Point is that a truck with not get gret mileage, no matter how it is set up...of course, I would love to get 19 mpg out of my 6.0l, but that will never happen.