'03 GMC 6 litre mods

supermax · Sep 8, 2008

I have an '03 GMC 2500 4X4 EC short box with 6L motor, 8600 GVW truck, 166,000KM on it. Mechanically very sound and it runs great.
I haul two Rubicons on an STF deck and pull a 22 foot bumper hitch travel trailer, quite a load for the truck.
Truck is 100% stock.

Been thinking of a chip, or a tuner, maybe some short tube headers and a cat-back system...or a new full dual system with long tube headers...my son installed long tube headers on his 1500 5.3 Z71 last spring and it pulls a lot better now.

Anyone mod one of these trucks?...what did you do first?...and what were the results.

I'm not trying to gain fuel economy, if I wanted better economy I'd stay home...

mb1 · Sep 8, 2008

supermax said:
I have an '03 GMC 2500 4X4 EC short box with 6L motor, 8600 GVW truck, 166,000KM on it. Mechanically very sound and it runs great.
I haul two Rubicons on an STF deck and pull a 22 foot bumper hitch travel trailer, quite a load for the truck.
Truck is 100% stock.

Been thinking of a chip, or a tuner, maybe some short tube headers and a cat-back system...or a new full dual system with long tube headers...my son installed long tube headers on his 1500 5.3 Z71 last spring and it pulls a lot better now.

Anyone mod one of these trucks?...what did you do first?...and what were the results.

I'm not trying to gain fuel economy, if I wanted better economy I'd stay home...

I think You're on the right track, exhaust, intake and then a tuner. Should wake it up a bunch.

medler · Sep 8, 2008

Do you know what gears are in it???

supermax · Sep 8, 2008

medler said:
Do you know what gears are in it???

4.10's, and 245-85-16 Vativa tires

wish it had as much get up & go as the LS2 6.0 litre in my '05 Corvette...

medler · Sep 9, 2008

Well ya got the right gears for towing..Cold air intake ,K&N and exhaust for sure.I had a hypertech in my old truck and it made the most diff.on premium fuel that was what i found anyway.

mudbitchguy · Sep 9, 2008

I had an '04 and put in and Airaid Cold air intake and Hypertech Programmer and it made a world of difference. Exhaust would also help.

Rej

xsyourride · Sep 9, 2008

Air Aid stage 2 intake,Air Aid throttle spacer and exhaust are your best bet.After you done those three than do a chip.The chip seems to work best after you do the other mods.
Air Aid intake: Retail $ 412 , snow & mud members $360
Air Aid Intake spacer: Retail $160, S & M members $ 140
Flow Master 3" out the side non alumminize pipe : $415 ,S & M member $364
Magna Flow 3" out the side stainless:$565 S & M members $494
This is what you would roughly be looking at for parts and prices to give your truck alittle more zip.If your interested PM and I can Help you out.

OVERKILL 19 · Sep 9, 2008

xsyourride said:
Air Aid stage 2 intake,Air Aid throttle spacer and exhaust are your best bet.After you done those three than do a chip.The chip seems to work best after you do the other mods.
Air Aid intake: Retail $ 412 , snow & mud members $360
Air Aid Intake spacer: Retail $160, S & M members $ 140
Flow Master 3" out the side non alumminize pipe : $415 ,S & M member $364
Magna Flow 3" out the side stainless:$565 S & M members $494
This is what you would roughly be looking at for parts and prices to give your truck alittle more zip.If your interested PM and I can Help you out.

Why use the Airaid over AFE? I see all you have on your trucks is AFE. Just curious. With this set up do you gain any milage? Thanks

xsyourride · Sep 9, 2008

OVERKILL 19 said:
Why use the Airaid over AFE? I see all you have on your trucks is AFE. Just curious. With this set up do you gain any milage? Thanks

AFE are great systems .All my trucks have been diesels and in my books AFE is number one for intakes on diesels and the only system I will us on a diesel.They also make gas job intakes just more money.Air Aid on gas is the best out there in my opinion aswell as AFE gas intakes .I have Air Aid intake and throttle spacer on my wifes yukon with 5.3 L and works great.I was getting around 18 to 19 mpg and after I put the intake and spacer on 21 to 22 mpg.

OVERKILL 19 · Sep 9, 2008

I have the same truck as Supermax, when I'm ready to upgrade I will defenenly be buying it from you, thanks for you good info and help :beer:

:d.

OVERKILL 19 · Sep 12, 2008

What is the best chip for this truck? How much?

xsyourride · Sep 12, 2008

Super chip $393 for the flash and $440 for the Cortex.Those are your best bet or a hyper tec which will run you about the same price $393.

Summitric · Sep 13, 2008

The superchip works awesome on these trucks... We put 2 in this week. Both customers have raved about them already. Its the best bang for the buck -- best value.......... Just my 2 cents

medler · Sep 14, 2008

I have an 08 3/4 ton with the 6.0L , 4.10 gears .It has only 5000K .I checked my millage yesterday and just about fell over,stock no aftermarket stuff on it 19.4 mpg,,i could have got 20 or better but iwas driving on the crazy # 2 and going into a side wind,and the quad was in the box too.iam happy over that ,

supermax · Sep 17, 2008

medler said:
I have an 08 3/4 ton with the 6.0L , 4.10 gears .It has only 5000K .I checked my millage yesterday and just about fell over,stock no aftermarket stuff on it 19.4 mpg,,i could have got 20 or better but iwas driving on the crazy # 2 and going into a side wind,and the quad was in the box too.iam happy over that ,

That is incredible mileage for any truck...but a 3/4 ton 6.0L....that's amazing

I've had my '03 2500 6L for three years and I've never ever checked the mileage.I figure it doesn't matter because I'm going camping regardless if it's 4mpg or 14.....:d

speaking of mileage with a 6L Chevy...here's one that's hard to believe.

In July I bought a 2005 Corvette with LS2 6 litre motor and automatic. On the trip back from Texas the best I got was 30.6 to the US gallon....that's about 35 to the Imp gallon and less than 8 litres/100K....it averaged 28mpg to the US gallon....this at 70-80 mph.....gotta like that for a 400 hp car

medler · Sep 17, 2008

Oh ya that is good.I think if the makers wanted to they could get great millage on allmost anything.Have you got your aftermarket stuff on the truck yet?

03rmk8 · Apr 11, 2009

ive got an 05 6l 15hd cold air dual exaust bully dog programer. I love the extra zip the combo gave the truck but im always looking for more

KingCatz · Apr 11, 2009

supermax said:
In July I bought a 2005 Corvette with LS2 6 litre motor and automatic. On the trip back from Texas the best I got was 30.6 to the US gallon....that's about 35 to the Imp gallon and less than 8 litres/100K....it averaged 28mpg to the US gallon....this at 70-80 mph.....gotta like that for a 400 hp car

Automatic in a Vette??? Isn't that like a penis on a hot girl? It works, but I wouldn't wanna use it. :d

supermax · Apr 15, 2009

medler said:
I have an 08 3/4 ton with the 6.0L , 4.10 gears .It has only 5000K .I checked my millage yesterday and just about fell over,stock no aftermarket stuff on it 19.4 mpg,,i could have got 20 or better but iwas driving on the crazy # 2 and going into a side wind,and the quad was in the box too.iam happy over that ,

Is that normal mileage for these trucks?

I've noticed strange differences in mileage over the years between trucks...in 1998 I bought a new Z71 ext cab long box with 5.7 litre automatic...one of my brother's bought the same truck in a 2WD short box...mine would get 22 on the highway...he could rarely get 20.......
bac in the late 70's I had a '77 2WD Chevy short box with 454....it would knock down 20 on the highway if I drove like a civilized person..once in a while I even did....same brother as above had a '77 long box 2WD with 305...he couldn't get 20 on the highway.....

In the 3-1/2 years I've had my 2003 2500 6.0 I've never ever checked the mileage...but it aint good...maybe it's better not knowing:d

medler · Apr 16, 2009

supermax said:
Is that normal mileage for these trucks?

I've noticed strange differences in mileage over the years between trucks...in 1998 I bought a new Z71 ext cab long box with 5.7 litre automatic...one of my brother's bought the same truck in a 2WD short box...mine would get 22 on the highway...he could rarely get 20.......
bac in the late 70's I had a '77 2WD Chevy short box with 454....it would knock down 20 on the highway if I drove like a civilized person..once in a while I even did....same brother as above had a '77 long box 2WD with 305...he couldn't get 20 on the highway.....

In the 3-1/2 years I've had my 2003 2500 6.0 I've never ever checked the mileage...but it aint good...maybe it's better not knowing:d

Not sure about normal but i went to Edmonton last weekend .From Airdrie to Edmonton and back 19 mpg.Didn't notice a tail wind ,,maybe it has a mind of it own.

'03 GMC 6 litre mods

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