6.7L Cummins Forum

Im going to be putting an exhaust on the truck soon and was wondering what your guys thoughts were on whats working and sounding good out there. I prolly just do filter back seeing how i want good sound but with hauling horses around a lot i don't want to choke them out with black smoke. Was thinking something like 4 inch straight filter back.

I believe our stock exhaust pipes are 4 in already....I may be worng....

Yes they are 4 inch stock and I think a nice 4 inch back with no muffler wold be fine. The DPF and Nox and cat will muffle the exhaust enough that you will not evan need a muffler. It is a tiny bit louder but nothing crazy loud. I took my muffler off before i did a turbo back straight pipe with just a free flow muffler and it sounded fine. just know that if your stock exhaust is 4 inch from the turbo back stick with 4 inch from the filter back. it does no good and there is no benefit to putting on a 5 inch pipe from the filter back because your still have 4 inch were it counts. In my opinion your just wasting the money by buying a 5 inch filter back pipe. If your gonna do 5 inch go all the way back to the turbo. But of course then you would have to do a Delete. good luck with whatever you decide!

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08 6.7L engine NOT STOCK, 6 speed auto, 2 inch leveling kit with 285/70/17 Toyo Open Country AT, 3.73 rear end, SLT package, 22MPG@70MPH , RBP fuel additive.

Ya i would like to do a turbo back with some sort of muffler eventually. Just got to let the warranty run out on the truck. (bought truck in 10', dealer gave me an extra 4 year 100 thousand bumper to bumper on it) But i do want to put a cold air intake on the truck here in the next month. So figured i'd try to open up the exhaust a little, plus add a little tone to the truck.

Hey just a heads up. I check with my dealer here, before I did it but they told me that a cold air intake will void your warranty. "They" claim, and i swear this is what they said, that because a 6.7 has some much more suction that it could suck in dust and ruin the top of your cylinder heads. They called it "dusting". I am standing there thinking did he really just say that? I mean isn't that why we have filters in the first place? To filter out the dust? What a dumbace!! Plus most aftermarket air intakes are higher quality than stock and filter down to a higher micron. Plus I could see if your out 4 wheeling in the dirt and dust all the time, but normal ROAD driving you have no worries. And I have never heard of any freak sand or dust storms where I live. So I went with an S&B cold air intake, with the dry filter and a filter wrap too. So bottom line my friend is if you have a cold air intake on your truck and something goes wrong with your engine, even if the intake has nothing to do with it I can garuntee that the dealer will make damn sure it does so he can void your warranty so be careful. And always save your stock engine parts!!! Also the factory warranty is up on my truck anyway, I do have an aftermarket extended on it, but I said screw it and did it anyway. Let her breath!!!

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08 6.7L engine NOT STOCK, 6 speed auto, 2 inch leveling kit with 285/70/17 Toyo Open Country AT, 3.73 rear end, SLT package, 22MPG@70MPH , RBP fuel additive.

I called and talked to my dealership and the dealership's Lead Mechanic and asked if they would void my waarranty if I put a CAI on my truck and he told me know, cause it makes the truck run better.....

I think it's weird how different dealers give different answers....I think it is stupid, shoul db one standard across the board no matter WHERE you are!!

Guys,
Just a point here. There is legislation to protect you from 'sly' dealers. They have to prove that any mod you did to the truck caused a failure. We all know that an aftermarket intake with improved filtration and improved airflow is going to have only one impact on the engine - improved power and economy. I put a K&N on my '08 2500. It loves that extra airflow. As a note, when you remove the stock intake you will hear the turbo spool more prominently. The reason is that the stock intake has a baffle to reduce the whine of the turbo which of course also reduces the airflow into the engine. I personally like the sound of the turbo.

Here is the wording from the legislation:

Under the provisions of the Magnuson-Moss Warranty Act of 1975, an automotive dealership/carmaker cannot void your warranty because your vehicle has been modified with aftermarket parts. They (the manufacturers) have to prove that the failure was the direct result of the installed aftermarket part. Unfortunately, too many folks have gone to a dealer to have warranty service performed on their modified vehicle only to have the dealer refuse to cover the defective items. The dealer usually states, that because of the aftermarket parts installed, the warranty is void (without even attempting to determine whether or not the aftermarket part caused the problem). This is illegal...period.

Little rant here ...... Magnuson-Moss Warranty Act is not going to protect you from anything and keep your warranty from being voided. Lets be real honest, you change to a CAI and do like some folks I know never follow the directions for cleaning and oiling and blow a turbo, now who's fault is it ? Do you expect the dealer / manufacturer to cover it ? Do you think you claiming you are protected by the Magnuson-Moss Warranty Act to a dealer is going to strike fear into them ? They deal with this daily and still all turn a profit. They have actuarial tables for all these risks and they do not favor us at all. Bottom line, want to play, need to pay.

Ok, spoke my peace ....

Be careful with aftermarket filtration, not all of them are good and improve filtration. Its one of those things that you need to do your homework on and understand what is going on. Understand what the filter and installation kit is trying do and are you going to get any benefits from it. I have seen aftermarket kits actually be worse performance than the stock airbox but sounded really cool .....

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