8.1 Zf Six Speed Power Questions

JRayls2500hd · April 16, 2008

i have an 8100 in a 2003 2500hd 4x4 six speed with 285s on it. i have removed the muffler and was wondering what i could do to wake this beast up even more. ps iv heard cutting the bottom out of the airbox is the the same horsepower increase as if you bought a cold air intake is this true?

Killerbee · April 16, 2008

i have an 8100 in a 2003 2500hd 4x4 six speed with 285s on it. i have removed the muffler and was wondering what i could do to wake this beast up even more. ps iv heard cutting the bottom out of the airbox is the the same horsepower increase as if you bought a cold air intake is this true?

no

dewfpo · April 16, 2008

Get a CUSTOM ECM tune like PCMFORLESS, WESTER's, etc... not an off the shelf, canned programmer. It's the best HP bang for the buck.

DEWFPO

ATMINF · April 19, 2008

I would also say that a PCM tune is the best bang for the buck that is simple to do. I would recommend Charlie Wheatley, at Gowheatley.com I have a tune from him in my truck and it really woke it up. Doing the airbox thing may or maynot help, because cutting the bottom out of the box will allow heated engine compartment air in at low speeds. A true CAI may help(there is alot of debate on this issue), I would say if you want to Full lenght Headers are always going to help add power, but its more money and does take some tiome and effort. Hope this helps.

truckin-on · May 5, 2008

i have an 8100 in a 2003 2500hd 4x4 six speed ... what i could do to wake this beast up even more. ...

I have a '97 454 with a 5-speed. The big-blocks really need serious air-flow in and out. I put Banks headers and exhaust on mine along with a K&N filer, and it really helped the power and mileage.

Dave

Daubs · May 7, 2008

I'm thinking your 2003 with the 8.1 Big Block has the 5 speed Allison...The 6-speed didn't become available until later (my 04 HD 8.1 has the 5 speed). Not that it matters much in your original post...

If you really want power from the Big Block there is a company out there that makes aftermarket heads and intake for the 8.1 (can't find the site...sorry, it's late and I'm tired). If I remember right it would cost you a pretty penny but would get you in the neighborhood of 500 HP and 600 lb/ft TQ. Granted, you would have to beef up the Allison.

On the more economical side, new intake, exhaust and PCM tune will do you well. Westers really wakes up the Big Block...

Swang · May 13, 2008

Nice truck, 6 speeds are fun with the big block. I have the manual in mine and its a blast. I've got some info from a guy who talked to a Raylar Rep (they are the company mentioned in the above post that he couldn't find), and he said do not bother with headers, the manifolds are plenty even with heads and a cam. Do the intake and a tune and that will make a large difference.