4" Exhaust?

[RDF1]

Been doing a lot of reading and never seen it mentioned on here.
Anybody running 4" exhaust?

On the '91 i have right at 48" of room from the trans cross member till the rear shock so i found a 30" 7" round muffler and a 18" 6" round resonator. Well there went all that room.

I have 3.5" down pipe from the turbo past the firewall then it steps up to 4" and plan to run the resonator as close to the transmission as i feel comfortable and then to the muffler and have to snake around the shock and i left enough air gap between the frame and the fuel cell behind the axle to put a 4" tailpipe and looks like its going to work out pretty good.
Just got to figure out how to do some type of turn down so it wont melt paint on the roll pan.

 

[GarrettGmc]

I dnt know anyone running a 4 inch on a gas motor only diesels but I'd imagine it wouldn't be that great, I could be wrong tho.

 

[phule]

He didnt mention it wasnt a diesel & also stated it has a turbo. Thus 4" would be fine.

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[GarrettGmc]

**** I feel stupid, read right over the turbo part Haha. Then yea a 4 inch would be perfect, I had a 4inch turndown on my Cummins an lived it. Not to loud but loud enough and didn't sound like crap like most 5inch

 

[RDF1]

Crap I forgot to put it was going to be on a 5.3 with a S475 turbo.
I got a buddy that had a 5.3 and S476 billet compressor and it made a huge difference on spool going from a 3" exhaust to a 4" exhaust.

I really wanted to do 3.5" but could not find any 3.5" stainless exhaust pipe that wasn't going to cost $100+ to ship. I have endless supply of 4" stainless thin wall (.050") pipe at work too. So after talking to a few muffler and resonator companies I decided on the large 30" magnaflow style muffler and the largest resonator I could fit.

I really want it to be quiet in the cab cruising. And wanted the flow for the faster spool and to make some power.
Waiting on the 4" Vbands to get here and I'll have it done.
Unfortunately I'll have to pie cut all my bends since all I have is straight sticks. But one curve around the shock and keep it high over the axle and tuck it close to the frame with some type of hidden turn down.


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[RDF1]

Well 4" ehaust is heavy... but it's all done minus a couple 4" Vbands to go before resonator and after muffler, and bunch of final welds on the tailpipe.
The thousand pie cuts around the shock, over the axle, and between frame and fuel cell was no fun.

After finding the stainless pipe at work I have less than $150 in the whole thing.

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[GarrettGmc]

Some bad ass work man.

 

[Biggershaft96]

how loud is it?

 

[RDF1]

Some bad ass work man.

Thanks a bunch! First time dying by a thousand cuts haha
It was quite a learning experience tho.

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[RDF1]

how loud is it?

It's dead silent right now.
I got fuel lines to tidy up and bunch of wiring to do before I can hear it.

Was really hoping for the v bands to be here 2 days ago. Once I get them welded on the exhaust will be ready minus wrapping a good bit of it

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