4" exhaust for the 6.0

WhitH · 11-18-2016, 04:18 PM

So as it seems often happens, I've done several things to improve the van over the last numbers of months and now I've decided to sell it. One of those things was adding a 4" exhaust only a week ago! Oh well, it made the van better so I'm happy about that and hopefully the next owner will appreciate it.

The kit is this part number from Diamond Eye K4355A. Its supposed to be a 4 inch turbo back kit, but of course the down pipe off the turbo has some flat spots in it to squeeze by the dog house. I had them wrap the pipe all the way down to the bend.

Observations....its great. I was of course concerned about drone during the decision making process so I was anxious to put it on the road and find out. There is a tiny bit between 1500-2000 rpms and medium throttle going around town and from 50-55 but it isn't bad at all. Cruising at over 60 there is little nothing discernable at all. In fact, audibly there is no discernable difference over stock while on the freeway. It sounds fantastic when it fires up, a lot like a large gas V8, then the turbo starts to turn and you just hear the whistle. Again, from in the cab and with the windows up its far short of obnoxious in my opinion. You can hear the turbo more from outside the van though.

Performance wise I am surprised at how much of a difference this exhaust has made. The throttle response and general peppiness of the engine are very noticeable. It just breathes and turns over so much easier now than before.

EGTs are 150ish degrees lower now. I drove it up I5 from Eugene to Portland and when it used to run just below 800 while cruising its slightly below 700 now. There is one decent hill to pull near Salem so I've not had much opportunity to observe EGT on the long pulls that can really get it up there, but my observation here was that temps were a little over 150 degrees lower.

A couple of things of note here. I didn't have a kitty on before at the 3.5" size and this kit also does not have one. I'm pretty sure they sell one that can be included though if needed.

My diesel shop did the install and they did mention that it wasn't exactly plug and play as it would imply. The kit is listed specifically for this van, but they said there is a chance Diamond Eye was just in a rush after SEMA and may have sent a couple of slightly incorrect hangers. Either way it didn't sound like it was a big deal and they were able to make it work.

All in all, for the money I would highly suggest this upgrade for both performance and turbo safety.

I've not had enough time to make any fuel mileage observations worth mentioning.

eddyturn · 11-18-2016, 10:12 PM

Good to hear!

JoeH · 11-18-2016, 10:24 PM

So, that kit has a 4" downpipe that fits? Stock is 3" and only makes it past the dog haus because it's been flattened at the bends. When I looked into it I couldn't find anything off the shelf.

I killed the kitty and had a high flow muffler installed but kept the 3.5" pipe on the rest of the system. I had a similar drop in EGTs of ~100 to 150F.

Just curious but are you running a FICM tune and/or PCM tune and what are your normal EGTs?

WhitH · 11-19-2016, 12:26 AM

I believe the downpipe in this kit is actually 3.5" I believe and going to 4" after that. The part number above can be found on Diamond Eye's website and I believe was only added earlier this year there.

My tune is an SCT which I believe just tunes the ECM...or PCM I can't remember? Only one of the two. My FICM hasn't been tuned or altered.

Typical temps were 800ish cruising on the freeway going up depending on load etc but I never had a problem with it going over 1200 degrees for any length of time even over some of the passes around here that I drive over regularly. It would get pretty close to it though for short bits if I was hustling a bit.

JoeH · 11-19-2016, 09:26 AM

Well, somebody will be stoked to have that free-flowing exhaust. Good luck with the sale.

The Atlas40 FICM tune raised my EGTs the most but the higher HP PCM tunes push it pretty hard ~1400F @ WOT as well. I've settled on 80HP being the sweet spot for my van. I've been thinking about going 4" turbo back but I'm pretty pleased with the mods completed for heat management. Cruising EGTs are 800 to 900F (pre-turbo).

WhitH · 11-19-2016, 10:03 AM

i know, I got to enjoy it for about a week!

JoeH · 11-21-2016, 10:45 AM

Well, thanks for posting the info on the updated kit. The only other 4" option for the E series 6.0 to my knowledge was the MBRP but that was a cat back. MBRP | Products

This is the muffler I'm interested in if and when I upgrade my exhaust: Aero Exhaust AT4040XL 4" inside diameter (Medium Sound)

A 3.5" downpipe that works without modification would be the main reason to do anything at all.

**daveb** · 11-21-2016, 03:19 PM

Quote:

Originally Posted by WhitH

I was of course concerned about drone during the decision making process so I was anxious to put it on the road and find out. There is a tiny bit between 1500-2000 rpms and medium throttle going around town and from 50-55 but it isn't bad at all. Cruising at over 60 there is little nothing discernable at all. In fact, audibly there is no discernable difference over stock while on the freeway. It sounds fantastic when it fires up, a lot like a large gas V8, then the turbo starts to turn and you just hear the whistle. Again, from in the cab and with the windows up its far short of obnoxious in my opinion. You can hear the turbo more from outside the van though.

Best news I've heard so far although I'm worried about the turbo noise cause mine is loud enough right now after the engine was bullet proofed. I'd also need a CA-Smog approved system. Do you think a cat would help to quite it down and what would one do to the performance?

Quote:

Originally Posted by JoeH

The only other 4" option for the E series 6.0 to my knowledge was the MBRP but that was a cat back. MBRP | Products

This is the muffler I'm interested in if and when I upgrade my exhaust: Aero Exhaust AT4040XL 4" inside diameter (Medium Sound)

A 3.5" downpipe that works without modification would be the main reason to do anything at all.

Post if you do it. I'd like to go that route but have always been concerned what one member posted a few years back about the excess drone noise.

gnty · 11-21-2016, 08:03 PM

Quote:

Originally Posted by JoeH

Well, thanks for posting the info on the updated kit. The only other 4" option for the E series 6.0 to my knowledge was the MBRP but that was a cat back. MBRP | Products

This is the muffler I'm interested in if and when I upgrade my exhaust: Aero Exhaust AT4040XL 4" inside diameter (Medium Sound)

A 3.5" downpipe that works without modification would be the main reason to do anything at all.

I did the 4" MBRP cat back kit, had the local muffler shop remove the cat and build the rest of the kit 4" all the way to the turbo. When i picked it up there was a heavy vibration at idle, pulled it back in and the down pipe still was still touching, the squished the down pipe a little more and it clears great. Noise is subjective to each, I think it sounds great and is not obnoxious, i think it sounds strong. You certainly hear it when you open it up, but cruising on the highway i don't notice much difference over stock.

WhitH · 11-22-2016, 06:57 AM

Dave, I was running the stock exhaust without CAT before this and the turbo isn't any louder inside the cab now than it was before. I can hear it, but it's not obnoxious and in my opinion sounds good. Having said that, adding a CAT to this or any system would quiet the turbo down significantly I would think.

Gnty puts it well I think, the system just makes it sound strong and like it's got some grunt. I've heard plenty of 6.0 and 7.3 trucks running around with straight pipes and it's nothing approaching that.