LB7: Exhaust and EFI Live?..

[Kustishen]

I plan on doing some small mods to my 2004 Duramax. Currently the truck is 100% stock other then 285 bfgoodrich tires. I don't plan on putting an intake on truck from what I have researched. Probably Swiss cheese the intake box and K/N filter for intake.

Exhaust: I would like to go straight pipe but don't know if I just do a muffler delete or go 4 inch straight. Will this even help if I keep the stock down Pipe? I think the 4 inch will help lower EGTs but if my down pipe is only 3 inches??? Plan on keeping stock turbo.

EFI: Plan on getting a mild tune from Idaho rob. Will his tune delete the regulations currently on the ECM? Do I have to do all exhaust mods before tune?

Goal: Improve gas mileage and performance and sound. just use truck to pull my 21 foot ranger for walleye tournaments.
thanks for your input!

 

[WolfLMM]

Honestly, a 4 inch is a waste. For stock turbo lb7 3-1/2 is plenty. Just cut out your stock muffler and go straight for more sound. You can mod in any order you want with your truck.

 

[OregonDMAX]

Don't mess with the factory exhaust just get a good 4" system it will be better than anything you can do to the factory junk.

Not sure what you read but the intake on the lb7 and lly trucks is a joke and adding a k&n filter it won't do you any better.

 

[TheBac]

Intake is fine. Just put a good filter in it. (which K&N is really not for this application)

You can either straight pipe your stock exhaust or buy a decent aftermarket. Downpipe causes no issues.

What do you mean when you say, "Will the tune delete the regulations in the ECM"? Rob would use your stock operating system (or one like it) to create your tunes. You then upload those in place of the stock tune. But, it would be a good idea to first save your stock tune in your computer or on a memory stick.

 

[THEFERMANATOR]

Don't mess with the factory exhaust just get a good 4" system it will be better than anything you can do to the factory junk.

Not sure what you read but the intake on the lb7 and lly trucks is a joke and adding a k&n filter it won't do you any better.

To many people now associate the 06+ intakes flow abiliy with the earlier ones now. When the LBZ came out, it was quickly found they could support 500HP without nay issues, so now they think they ALL can. I've seen to many bone stock trucks suck the filter indicator down to the red with new filters to even consider leaving one in. The biggest problem is there are 2 different filters to fit the earlier box, a gasser version, and a diesel version. Most parts stores sell the gasser version for all of them, and they just can't move the air. And the K&N is a joke. I went with an AFE dry for mine, but I need to build a custom intake for it one of these days.

 

[Stancedlb7]

Check your local laws before you straight pipe your exhaust. Swiss cheese intake with a good dry filter is more than enough. And unless your trucks from Cali there are no "regulations" or emissions on an lb7.

 

[catman3126]

To many people now associate the 06+ intakes flow abiliy with the earlier ones now. When the LBZ came out, it was quickly found they could support 500HP without nay issues, so now they think they ALL can. I've seen to many bone stock trucks suck the filter indicator down to the red with new filters to even consider leaving one in. The biggest problem is there are 2 different filters to fit the earlier box, a gasser version, and a diesel version. Most parts stores sell the gasser version for all of them, and they just can't move the air. And the K&N is a joke. I went with an AFE dry for mine, but I need to build a custom intake for it one of these days.

Hell mine does that with an AFE and a LBZ mouth piece. guess we will see what this Werhli fab 5" does on the new motor.

 

[Bersaglieri]

I went the cheap route with my initial LB7 mods. Straight pipe from ebay and it came with a K&N filter in the stock box, which K&N replaced for free because the rubber surround was starting to crack. I've since added gauges and some conservative tunes from IdahoRob. The truck does well daily driving and towing. Most would probably be fine stopping at this point for towing a boat. Mine does well towing 10-12,00lbs.

At times I'm tempted to buy a nice stainless exhaust and intake, but I tell myself to save that money for a full transmission rebuild which I'm sure is inevitable.

It's easy to fall into the rabbit hole and dump money into diesel trucks hand over fist. I say for your needs, start conservative and that's not enough, you can really throw some money around.

 

[Kustishen]

Thanks

Thanks for the responses, I took the KN filter and got a SB filter. Sounds like they make a better filter.

Can anyone else confirm the 3.5 to 4 inch exhausts it just sound preference? I thought the 4 inch would help with egt? Plan on getting mild tunes eft from idahorob.

My question about the ECM is that I was reading a lot of guys delete the factory sensors, egr, ect...to help performance. when you get a tune does it delete them or is that something you pay extra for?

 

[melms23]

Thanks for the responses, I took the KN filter and got a SB filter. Sounds like they make a better filter.

Can anyone else confirm the 3.5 to 4 inch exhausts it just sound preference? I thought the 4 inch would help with egt? Plan on getting mild tunes eft from idahorob.

My question about the ECM is that I was reading a lot of guys delete the factory sensors, egr, ect...to help performance. when you get a tune does it delete them or is that something you pay extra for?

You shouldn't have to worry about an egr. They were added on lly and newer unless it was from California i believe.

 

[Stancedlb7]

As long as your trucks not from Cali your good with zero emissions. And at your power level nothing after the turbo will help egts. Save for a tranny build!

 

[WolfLMM]

Thanks for the responses, I took the KN filter and got a SB filter. Sounds like they make a better filter.

Can anyone else confirm the 3.5 to 4 inch exhausts it just sound preference? I thought the 4 inch would help with egt? Plan on getting mild tunes eft from idahorob.

My question about the ECM is that I was reading a lot of guys delete the factory sensors, egr, ect...to help performance. when you get a tune does it delete them or is that something you pay extra for?

4 inch will not make a difference in performance in ANY way. Not on a stock turbo truck.

My 2001 makes 650hp on factory exhaust. That's with a s366...

Sound might change slightly. But they sound really good with factory exhaust straight piped.

 

[OregonDMAX]

4 inch will not make a difference in performance in ANY way. Not on a stock turbo truck.

My 2001 makes 650hp on factory exhaust. That's with a s366...

Sound might change slightly. But they sound really good with factory exhaust straight piped.

The lb7's are EGT whores, I dropped egt's going to a 4" from the factory exhaust. Say what you want but that's my experience.

 

[WolfLMM]

Stock turbo has high egts regardless. It ain't worth it.

 

[catman3126]

The lb7's are EGT whores, I dropped egt's going to a 4" from the factory exhaust. Say what you want but that's my experience.

EGT' whores?? whats that even mean?
Drive a stock LLY if you think your LB7 has high egts. I could get mine to 1375 deg with no tuner and a cat back exhaust and afe intake with the stock mouthpiece. I bet you LB7 doesn't do that stock??

 

[OregonDMAX]

I don't k ow what I did stock because I didn't have a way to monitor but with just efi on it and CTS gauges it would see 1600 and higher quite often. Since doing a ton more mods I peaks at 1400ish