I have a stock 2500HD at this point and I am looking to upgrade the exhaust. I am looking more for mpg increase than anything else. I am on a limited budget so I am doing the basic upgrades a little at a time. I have ordered a Kodiak mouth piece and I would like to order the exhaust sometime this week. The future plans of the truck are going to be geared for mpg increases more than anything. Are there any benefits going to a 5" exhaust with a muffler over a 4" exhaust with a muffler?

 

I say 5" straight, sounds dirty on a Dmax. That is my recommendation! You can get expandit kits for fairly cheap.

 

imo you won't gain any mpg on an exhaust on a dmax, the stock one has been proven to over 500hp just fine. all it will give you is sound. best bang for your buck for mileage is a tune, efilive can be had fairly cheap if you do not get the v2 just a pretuned ecm. probably about the same price as the exhaust would be.
straightpipeing mine did nothing for mileage i gained 4mpg with the tune though

 

idk you can get a 4inch exhaust for about 250-300 nowadays. its real cheap.

 

I have been thinking about the EFI LIve but at $900 to start there is just no room in the budget for that for a while. From what reading I have done not just here but other places I have not seen where a change of exhaust did not increase mpg. Not doubting you (turbostang7) just stating I now have more research to do.

 

you can get the whole efi deal for 900 for you can get an autocal, where you will get a deal that will flash ecm tunes into your truck and do basically all the same stuff as EFI live V2 will except it wont re-write the ecm to have five seperate tunes that can be switched by a ****. u will have to use the autocal every time.

they are much cheaper, like half the price.

 

or get it pretuned on your ecm like i did, have 5 tunes on a **** and all, just didn't buy the v2. and it was almost a third of that price!

 

only problem with that is that is you cant get updates on tunes right away or check for codes, or run diagnostics.

its awesome and its cheap and effective and there is no hassle with computers its plug and play. ive had my negative effects on having a mass distributed efi live tune, the problem is that it doesent make the same power on each truck.

some of the race tunes call for a high PW which can bring down the rail pressure to an inefficient level (20kpsi and lower) where you would be able to make more power/less smoke by changing the tune to have less PW. with a pretuned ecm and no V2 or autocal you cant diagnose the problem and get changes or take logs of the tune in action.


i never ran the tunes on the pre-tunen ecm so i dont know how it acts.

 

Mine runs awesome, no rail pressure issues, no smoke but rob coddens knows what he is doing . Plus if anything needs changed he has no problem doing it for you

Sent from my DROIDX

 

I've not had any issues with my DSP5 tunes from Nick either, they are nice and clean, but the highest hp is 415rwhp, which is well within the safe range for easy power to be made, its not taxing the CP3 really at all the 475rwhp tune I ran on the other hand was too much for my rig, I never logged it but im sure the rail pressure dropped like a rock at full fueling