bziggy

I'm looking at the 4" pacbrake system for my truck. As you can see in my list of mods, i'm not sure if I should go to a 5" instead. I am thinking that a 4" system will cause a restriction in the exhaust system when not using the brake and that a 5" system would be better in that it would create much less restriction in the exhaust system. Anybody have any thoughts? Pacbrake said that I wuuld not be losing anything in using the 4" system, but I would like to hear everybody's opinions. Thanks!

Fisherguy

If you have a 4" exhaust why would you want to use a 5" EB?
(I'd just go with the 4" in place of the stock elbow)

Sevir

if you get the inline pacbrake instead of the direct bolt it only comes in 5". that is what i have on mine and there is no problem. it will also come with reducers for a stock 4" exhaust system. This will also let you upgrade your turbos without having the replace the direct bolt system

Sandhopper

On the Pacbrake Topic, How difficult are these to install. Is there a lot of wiring? I have 5" Exhaust so I would likely go with the inline system.

wiskeyVI

If your going inline, it should work out great.

Fisherguy

I put mine in the elbow, installation was pretty straight forward.
Here's instructions for the inline one:
http://www.pacbrake.com/PDF/L2038.PDF

bziggy

I am looking at a 4" system so i guess it's a bolt on system. My concern is that is will be the "bottle Neck " in the exhaust system by going 4" and that i should go 5". Any one with a 5" system tell me how that works when you say a in line system. Thank you

Fisherguy

The stock elbow is 4" anyhow, there wouldn't be any more of a restriction, here's a pic of the stock elbow compared to the EB:

CD in NM

I have the 4" PacBrake installed at the elbow, I also have an exhaust pressure gauge. I saw NO change in my exhaust pressure with the PacBrake. Now I DO see a pressure change when the brake is on, right at a 60# difference, and that amount IS what the PacBrake applies in back pressure as advertised.


CD

bziggy

Thanks for the pics It was a great help. I was under the impression that it was like a 3.5" inside diameter and that does not look like it is so. thank you,

cbrahs

they changed the cast elbow in 04.5 to the 4". previous 3rd gen's were 3.5

C Schomer

I wanted to do the same thing til a vendor talked me out of the 5". He said the 5" won't brake as well as the 4" cuz of more leakage. I don't have any egt problem and I wanted the best braking - that was the decision maker for me. Pac DOES make a 4" inline - it's on my truck and I couldn't be happier with it. I bought the inline 4" with the 03 CTD control package. I had to do it that way cuz I already had a different turbo and homemade 4" DP. Craig

CrazyCooter

I can't speak for the elbow version since I have never measured one. But the inline units run smaller than the exhaust size OD.

I went with the 5" inline for my 4" exhaust. The 4" is around 3.5" ID and the 5" is around 4.5"ID.

Sevir

the 03's had a 3.5" exhaust while the 04+ have the 4" exhaust. if you went with a 4" inline with a 3.5" exhaust then that is roughly the same as me with a 4" exhaust going to a 5" inline.

C Schomer

When I changed my turbo I got energetic and built my own 4" exh (turbo back) and the DP clamps directly to the turbo - no cast iron elbow. So I used a 4" inline e-brake cuz that was a BUNCH easier than redoing my DP. Craig