3 inch to 4 inch exhaust benefits?

[Tthornton11]

hey ya'll haven't gotten to check on the forum much- first year of college was a heck of a lot busier than expected. Anyway back workin on the farm for the summer and truck progress is back to the forefront of my mind. I have baby swamps on order with swamps tunes coming with them, autometer gauges are also on the way but with the swamps upgrades i'm wondering if the 3 inch turbo back straight pipe i have in right now is going to cut it. will upgrading to 4 inch net me worthwhile change? As always, appreciate the wealth of info ya'll provide

thornton

[Frostbite]

Good question. I would say as long as you have a 3" downpipe and your catalytic converter is either gutted or gone that you should have plenty of flow. I called many perfromance shops and thry told me that going to a 4" exhaust was not needed on our trucks unless they had major modifications.

I went to a 4" exhaust and really didn't notice much at all. There may be performance gains from the 4" pipe if you have super large injectors an a big turbo but, with baby swamps, I doubt you'll need it. If athetics matter to you, cut 18" off the end of your stock pipe and put a 4" or 5" tip on the end.

I'm sure others will disagree but, this is what I have found in my reasearch and results.

[85_305]

Our trucks come with 3.5" exhaust stock... why the hell would you want a smaller exhaust than stock?

The bigger the exhaust, the better the egt control. There is a HUGE difference between power/mpg/egt between 3" dinky exhaust and 4-5" exhaust.

[BigFuel]

I'm with 85_305. Our diesels aren't like gassers in that they need precise exhaust diameters and paths because of how low our rides are to the ground or exhaust scavaging. Once the hot air is through the turbo get it out from under your truck.

[85_305]

^^^^^Amen!

[zrain25]

Get a the 4 in exhaust and don't worry about it agian. Plus it sounds way better. i think a 4 in diamond eye is 290 something


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[yngbuck19]

I went with five inch from the dp back with a five inch cat delete pipe it sounds sick and keeps temps and back pressure minimal the aero turbine muffler I'm about to put on it will make a vortex sucking the hot air away from the turbo I can't wait!

[zrain25]

Originally Posted by yngbuck19

I went with five inch from the dp back with a five inch cat delete pipe it sounds sick and keeps temps and back pressure minimal the aero turbine muffler I'm about to put on it will make a vortex sucking the hot air away from the turbo I can't wait!

Hey let me know how that muffler sounds like and if it lowers egts


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[Tthornton11]

thanks for the quick input- i went and measured today and it IS 3.5 inch straight, I can get 10 ft of 5 inch pipe for $160 or 10 ft of 4 inch for $112 from the local guy that does all the exhaust on our farm rigs. Is a more expensive brand name kit worth it? Attaching existing brackets, elbow and 3 to 5 inch adapter isn't too much work.

[85_305]

And the DP is def upgraded?