So I have about 180K on my PSD and it runs great...Well maybe....
I am about to order my DP tuner and 5 inch exhaust...And went through the truck to make sure all filters are new and fresh.....no leaking of anything anywhere. But one thing that came to mind and I thought I would ask just in case I am wrong here....

Does it take a little time for the turbo to build up pressure after really getting into it or is something wrong? Off of a light after driving normally, I can get on the throttle, the turbo kicks in and it sits you back in the seat....I get to the next light and if I sit there for a few seconds, it will act the same once I go...but if the light turns green just as I get there, I get on it and it just seems like there isn't quite as much "boost". If I lay off the throttle for a little bit then hit it again.....The boost is there.

I went through cleaning the engine by hand the other day and it did seem like there was some soot around the blue connectors on the air intake tubes, (flexible connections). I wiped them clean...and they seem to be staying clean, but wondering if maybe I am just being too picky.

 

my boost gauge starts to move around 1600 to 1800 RPM... the soot you cleaned up is oil from the CCV..you can try to tighten them clamps a little if you like... look for soot on the up pipes right behind the turbo..look from the top then get under the truck with a flash light and look up at the turbo...also look where they hook to the manifolds... congrats on the DP...your going to love that thing and the 5" will make it sound very nice....

 

Sounds like plain old turbo lag to me. The exhaust & DP will make a huge difference, so be prepared for that. The "soot" on the boots is probably oil soak from the oily crankcase gasses being vented into the turbo. Clean & inspect the boots real good and do the CCV mod.

 

Expect to loose a little more bottom end if you put the 5" exhuast on. I would go with 4". 4" is plenty big for what you are doing to the truck. From a guy with 5", I say go with 4".

 

I don't have a tuner yet, (see sig for mods) and mine does the same. Turbo starts wickin up at about 1600 and then you feel things starting to move. Everything I've read here this seems the norm.

 

Phew! Thanks for the info guys. I wanted to make sure that there wasn't something about to go. I would rather use the $$ to make sure all is OK now instead of spending it on the tuner then finding out I need to repair something else. But...for the exhaust.......
I do haul heavy loads a couple times a month...otherwise it is only about 6-7K each weekend. Will the 5 inch really kill my low end that bad or should I go for the 4 inch? I am not looking for sound, I am just looking for better flow.

 

So far, in all of my exhausting exhaust searches, the loss of low end is just in theory and I have yet to read one person that has run 5" and 4" to compare for sure. Remember, this is just my research, there could actually be someone that has run both systems and can tell you for sure. SO far, the biggest diff I've heard of is sound. I personally find it very hard to believe that there would be 'much' difference.

 

It is like tuning anything else, there are applications for everything, and with the whole exhuast size debate, I have always been told and read that you do not need 5" exhuast until you are in the 500 hp range. With that said, the only benefits with the 5" to be had are appearence and a slightly lower exhuast note, and membership to the cannon club. Another good bit of advice is to call jody @DP and see what he recommends. You want something that he matches or created his tunes on. This way you know that everything is working in conjuntion with each other. Maybe becuase he sees trucks coming to his shop for live tuning, he can offer advice on exhuast size based on the set-ups he see and tunes.

Other key things to remember, no muffler= drone and w/ muffler= no drone in the cab.

Now, some have done swaps between the 3.5" down pipe and the 4"downpipe and have noticed a SOP difference in the bottom end. Try searching for threads on this subject.

 

Well, not to be contrarian to Pullinair, but I come from the Mutang scene, and there is theory regarding larger exhaust causing more turbo lag. But the results according to Muscle Mustangs and Fast Fords says that the theory is incorrect. They say that in every application that they have seen with a turbo, the better the turbo can breath, the better the performance of the turbo. They said that they have seen no real world evidence that larger exhaust makes the turbo lag worse. FWIW.