I almost always bead blast parts to be powder coated, but never stuff to be painted. The powder coating is less forgiving to surface contamination and media blasting helps make a more uniform color, improving the consistency of coated parts.

 

Thank you SSJ!

 

Any advantage to changing to a 4" downpipe? And any mods needed?

 

Yes and no.

Disclaimer: I am not certified in anything mechanical other than I've spent a lot of time under the hood of my truck and have the empty wallet and bloody knuckles to prove it (and it's been almost 3 years since I've chased any oil leaks ).

I don't have any hard evidence for any of the following but will provide you with what I've gathered over the years and used to help make my exhaust decisions.

The stock exhaust is ample enough for stock injectors. There is a crease in the downpipe as it is not mandrel bent like other parts of the exhaust. Even with that restriction it is not a tipping point to shoot the buckz$$ka to replace it. As a compromise to replacement many have just replaced the muffler and been happy with that decision (one of the more popular choices is the Walker Big Truck Muffler).

If you have aftermarket (bigger) injectors then you can tap into the benefits of a mandrel bent 4" exhaust. That definitely fills up the gap where it passes through the engine compartment and can test your patience. I was doing other work so had a large area to work in (turbo and up-pipes removes) and was able to get the job done with a lot of paitence and some bungee cords. Others were not as successful (I believe @Sous cut his downpipe to finish his install).

I have only done the install with a full exhaust so don't know what you would need to drop in just a 4" downpipe or how you would mate that to the stock exhaust (if that was your question).

To take advantage of any benefits of the improved exhaust path you would need a complementary upgrade to the OEM intake for an increased flowpath from beginning to end.

 

I installed a full 4” turbo back kit. It went in pretty easy for me

The CSD T4 kit comes with a 3.5” downpipe so now I am 3.5” to a 4” with flow through type muffler.

So, many folks running T4 turbos are using 3.5” downpipes…

I believe the factory is 3.25”.

I have read that the main benefit is seen in just changing to a straight flow muffler like the Walker that a lot of guys use.

Read whatever you like into that info.

 

Brian42 is correct, years ago when I rebuilt my turbo and installed a 4" MBRP exhaust system I had to cut about 1.5' off the bottom end. Maybe this was due to my ZF6, but I could not get the DP up there with the up-pipes and turbo in place.

I even removed the transmission cross member. I liked my MBRP system, but later ended up removing the DP for one that came with the T4 kit I purchased.

 

SSJ do you use primer on your parts before painting them?

 

No.

Fresh today!

 

Absolutely beautiful work my friend! Like I said before I live in a place where things are not readily available so I had to order the VHT and the Rustoleum 2X paint %$$#$. Still waiting to be able to paint.

 

Thanks guys for the direction on the 4" downpipe.No bigger injectors yet so I think I'll stay with OEM for now.

 

There is no advantage to larger than stock exhaust. Dumping the muffler is equal to gains from 4”+ tubing. My truck has stock size tubing from DP back and makes 2.5x stock RWHP.

Stock exhaust is SS and will last forever in all but the rustiest climates.

 

 

Eva Bella probably knows more about 7.3’s than most people! She’s been watching me every day for years.

And yes, she knows the drill. Clean things, paint things... blah, blah, blah. She says more BELLY RUBS would be nice!!!!!

 

Beautiful companion and loyal helper enjoy her company while she is with you. My son lost his Great Dane last week after 9 great years together. Really a sad day for us all.

 

Sorry to hear about that.

We lost her ‘sister’ (labradoodle) 3 yrs ago. Daisy was the original travel dog, shop dog and 7.3 expert. She traveled all over the country and went to work with me every day when I had a real job. I always say she had more friends than me because at plenty of 7.3 get togethers, etc I was just ‘the guy with Daisy’.

We went to Niagara Falls a few years ago with Daisy, Eva and our friend’s Great Dane ‘Zipper’. Normally my lovey dogs get tons of attention, but Zipper always stole the thunder. People LOVED that big, goofy dog!!