4" exhaust build

[funnyman06]

Uploading videos as we speak, here is the first video.

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Edit: Looks like im going to have to cut the other videos down. They are little too long to upload. But this first one gives a pretty good idea of what it sounds like.

 

[funnyman06]

Brian did you get yours all put on?

 

[Brianedwardss]

Brian did you get yours all put on?

I did! I'm currently uploading my photos..

 

[My9373]

I did! I'm currently uploading my photos..

Can't wait to see and here this one, I like the system you put together a lot, and I'd like to hear what it sounds like to get a good idea of what to expect with my truck. Not thrilled with my 2.5 straight piped system right now at all. To boring sounding, and very raspy at high rpms, too much like a straight-piped gasser sound.

 

[funnyman06]

Brian, how different does it sound from my truck?

 

[Brianedwardss]

Alright, I'm back. The install went well. Here's how the day progressed.

I put the front of my truck on ramps to make it easier to get under, it's 2WD and kinda low. The valve cover seepage that I can never cure helped keep the manifold bolts lubed up and they came right off with an impact gun. Next I pulled the pins out of the hangers, cut off the muffler hanger at the welds on the muffler, and dropped the whole system. It became clear fast though that I was gonna have to cut off the tailpipe to get it out. So another 60 seconds with the cutoff wheel and the tailpipe was off, and the whole system was on the ground. That was ALOT easier than I thought it was gonna be..

Here's the systems side by side:

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The old Y-pipe went under the cross-member, the new one goes over, and doesnt show from the side of the truck. I always hated the old system hanging down below the frame for all the world to see. The new exhaust is up out of sight:

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The Dynomax kit doesn't come with a manifold flange for the drivers side, but the new pipe on that side is the same size as OEM. So to save money, I cut a flange off of the old y-pipe and used it:

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Installing the new pipe was a bit of a pita, but with some effort it went on. I had to turn it almost 360 degrees at times to get the hanger pin around the tranny, but it went in about two minutes time.

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The rest of the install is self explanatory. My welder was not wanting to cooperate today, something is wrong with the motherboard I think, so I just used the clamps that came with the kit. I did have to go buy a 2 1/4" clamp for the Y-pipe joint under the oil pan area. Here's the final product:

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The hanger pin that came with the Y-Pipe was in the perfect location. This kit is for a 6.9L truck up to '86, but the hanger location was the same on my '88 7.3L..

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I didn't have time to make a video, but I did get to drive it across town for the game, and it was pleasantly mellow for being NA. It wasn't raspy at all, even when I floored it once going up a long hill, it was pleasantly mellow. Its got a deep rumble at idle that you can definitely hear/feel in the cab, but as soon as I start moving, its not much louder than stock. I'm VERY happy about that. I think with the injectors I got coming from Mel, it'll run smoother, and sound sweet. As far as the butt dyno, I did noticed a bit more power, nothing off the line, but everything after. I didn't get a real opportunity to get on it, but its definitely quicker from 1300 rpms and up, no doubt about that.

Brian, how different does it sound from my truck?

It sounds about the same! Thanks for taking the time to make those. If you've got any more, lets see em! Your's/mine don't sound like a 460 with headers, just has a nice mellow rumble when we get on it. My ear drums weren't plugging up from the drone, the muffler did a good job of calming things down. All in all, I think it was a worthy investment. Time will tell, its only been on the truck for one evening, but I like what I'm seeing/feeling/hearing

Thanks for looking fella's

 

[Brianedwardss]

Tomorrow I'll take a stab at getting a video

 

[CDX825]

Looks Good!

 

[flareside_thun]

Looks great on there Brian....You're a better man than I am for doing all that laying on your back in that rock. Lookin forward to a vid of it......

 

[Agnem]

Your original Y pipe was definitely NOT a factory Y pipe. They did not go under the cross member. If you measure the cross section I'd bet it's 2.25" instead of 2.5". Probably a cheap Walker. The new system looks good, and should definitely let that engine breath better. What intake mods have you or will you do?

 

[Brianedwardss]

What intake mods have you or will you do?

Well it's N/A, I removed the soupbowl and restricter plate. I've got a modified 6.9l snorkel hooked to the factory plastic tube, drawing air in the 6.9l spot on the core support. Not sure what else to do intake wise.

 

[flareside_thun]

IDK about you, but from the reviews I've been seeing about the hypermax style cowl intake...I'm gonna give that a shot.....with home made parts of course...gives me an excuse to do a Hydroboost conversion too!

 

[Brianedwardss]

IDK about you, but from the reviews I've been seeing about the hypermax style cowl intake...I'm gonna give that a shot.....with home made parts of course...gives me an excuse to do a Hydroboost conversion too!

'Tis true. I forgot about the cowl induction thing, even though one of my trucks has one . Here's a couple more shots of the final product. Im changing the diff fluid over to synthetic today, and putting in a napa one-piece fuel filter, then I'm gonna take a stab at getting a video.

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[Brianedwardss]

Update, it's been two months, and here are some observations:

- Biggest change is under load. No longer is there the half throttle syndrome, where anything over half throttle makes absolutely NO change in engine rpms or sound. Now the engine under load will actually respond to the pedal and rev as high as I want it to.

- Going up long sustained 6-8% hills is vastly improved. With the 2.5", I'd lose speed and barely hold 45mph while going up some of the longest hills. I'm talking empty truck! Now on those long 6-8% grades, I'm able to keep atleast 55mph, and even accelerate if there's no head wind. I can mash the go pedal and the engine actually will respond while already climbing a hill. Its incredible how much more free the engine feels now.

- MPG, I've gained a solid 0.75-1. Most of what I do is commute, and average MPG was always 12.5, plus or minus 0.3. Since the exhaust, I have yet to have a tank under 13.1. With the old exhaust, I only hit 13 a couple times on road trips, but never in the city.

- City driving: Definitely noticeable. Acceleration has improved, especially over 2000 rpms. Getting on the highway, I can run right up to 65mph no problem, while before the truck would hit the wall around 55 and have to be coaxed to go much faster.

- Overall Conclusion: Definitely a worthy upgrade. I was always under the impression that NA IDI's didn't need a big exhaust. But now that I've got one, the engine is much more responsive, and the drivability of an 88 IDI crew cab is much better. The truck is no longer a giant slug in traffic. The greatest improvements are under load.

For budget NA'ers stuck with a C6 and looking for better economy, a fresh set of injectors, properly timed IP, and a more free-flowing exhaust has netted me a solid 2 mpg increase, along with making the truck much more enjoyable to drive, it's a win-win scenario

 

[plywood]

This is the first time I've seen this thread, good stuff.

I will have to buy a tailpipe for my CC, so I'll look into the powerstroke one for sure, I was just gonna order the one from Dynomax for over the tailpipe.

I have the same y-pipe, and the rest I built from pieces and used all U-bolt clamps since I don't weld much. Let's be honest, it's probably been over twenty years so I welded.

I've got a few videos, link below.

Mine is much shorter, is your muffler 4"? Point is, when I get on mine it's a little louder and rumbly then I really want. I hoped it would be more of a glasspack moan I guess then the reverberating rumble. This could be all from my 5" tip, or just cause it's shorter.

This is a great thread for me though cause I have to figure out what exactly to do with the CC. I've been thinking just the fact that it'll be about 10 foot more exhaust form a SC dumped in front of the tire to a CC dumped behind the tire will make just a litte more quieter.