Question 4 Inch downpipe

[grumpy929]

I installed MBRP 4" turbo back on my 6.0 Excursion. This exhaust performs very well and sounds excellent. I have had it on there for around a year and half with no problems.

With the 4" downpipe it is very tight, so I can't imagine a 5" would provide proper clearance without rubbing and banging on the firewall and surrounnding structures. Initially I had rubbing until I got it clearanced properly and no trouble since then.

 

[lil89ram50]

what do these trucks originally come with for a dp?

 

[no-red 6 0]

lil89-

Welcome and i know right where DL ND is - grandparents from there (and my dad too!) - are u under water yet?


factory tube is crimped/crushed 3" iirc

 

[lil89ram50]

lil89-

Welcome and i know right where DL ND is - grandparents from there (and my dad too!) - are u under water yet?


factory tube is crimped/crushed 3" iirc

haha thanks!! nope the water level has actually gone down a bit this year!!

 

[f100cleveland]

My son stopped by Heartthrob's shop this week to check out some exhaust for his truck and asked about their exhaust for diesels. They said the 4" dp is worth some power even useing the stock cat if you make the section on it that necks down to 3 inches 3 1/2". He said that mod works good even with the stock exhaust. They claim the stock modded cat flows good enough for anything but all out race. They won't do anything without a cat on unless its a full all out race vehicle.

 

[Beve]

I have a AFE 3.5 DP, cat delete, muffler delete and jus ordered a plain 4 inch tailpipe...there have been several studies that state that there is no significant HP or reduction of EGT from 3.5 to 4 inch DP...that is jus what they say..I love my set up..you can hear me a mile away..haha..once you get past the whistle it is very throaty...you can hear mine here...this was the first time I have taken my truck to the track..jus wanted to see how it would do..lil bit of a traction prob..haha..

beve at baytown- Video

 

[kingkevindavid]

i have read the same that downpipe doesnt make that much of a difference. I am sure if you were a professional and spent tons of money on a race truck, you would want to test different size pipes on a dyno. for street use I wouldnt sweat it to much.

Beve, your truck runs and sounds good! what kind of programmer you running and what year is the truck?

 

[Beve]

its an 03..6.0L...I have a SCT livewire...I wish I had the custom tune on it..I jus use the stock tunes they send with it..I dont wanna stretch a head bolt..haha..kinda scared...

 

[TopShelfCustoms]

The best thing to do is find someone that will custom bend a 4" DP from 4" mandrel tubing at a muffler shop. I had it done in bakersfield ca at Bobs muffler and that is the only true 4" DP. If you have a bolt-on DP and you measure before installing its a lil shy of a true 4" ID. The problem is there are not too many shops that can mandrel bend 4" pipe depending on your location. I got a TRUE 4" turbo back system all customs mandrel bent (due to suspension mods) and a 6" tip for $500 cant go wrong there and its was well worth the 1.5 hour drive.