4" exhaust- 3.5" or 4" downpipe?

Mwilbur516 · Oct 30, 2011

I'm getting a 4" turbo back exhaust and wanted to hear from some who already have them. Is there any rubbing on the firewall with the 4" downpipe and will I experience any power loss? My goal is to lower my EGT's and gain a little more power if possible. I've heard that some have experienced a low end power loss with 4" pipe. If it makes any difference I'm looking at the S&B intakes as well and the rest of my mods are in my sig. Thanks for the feedback.

yeehaw · Oct 31, 2011

my downpipe rubs on the bolt head on the trans cross member, besides that no issues sounds amazing

Mwilbur516 · Oct 31, 2011

Kyle, did you experience any low end power loss when you put the exhaust on? My next round of "upgrades" will include some 175/100's and a Powermax, thats why I think I want a true 4" turbo back kit.

yeehaw · Oct 31, 2011

i didn't at all, when i had just exhaust it drove pretty much like stock

Mwilbur516 · Oct 31, 2011

What kind of system (i.e. MBRP, Diamond Eye) are you running? What kind of temps do you see at WOT?

yeehaw · Oct 31, 2011

MBRP cool duals, and no idea still don't have an EGT gauge

ProCut · Nov 1, 2011

Mine has 4" straight from the turbo and Y's in front of the axle to dual 6" tips out the back. I have nothing to compare it too as I bought the truck as-is. With a 9" lift there does not appear to be any rubbing and it sounds awesome.

SSpeeDEMONSS · Nov 3, 2011

My 4" flowmaster rubbed. When I had my trans out I pulled the DP and "clearanced" it at any spot that looked like it had rubbed. I don't think I would ever go 4" DP again unless I was going for a high horsepower build. Might even swap out my 4" DP for a 3.5" one since that is all that's left of my exhaust.

Garrett

Probably getting paid at work to post this from my D1

PSM_Kid · Nov 7, 2011

I have a Magnaflow 4 inch turbo back with a 4 inch down pipe. During install, the down pipe is a tight squeeze in between the firewall and up pipes. But once it is in there, it fits awesome and does not rub on anything. The entire kit fits great, install is super easy and it sounds good too.

Mwilbur516 · Nov 12, 2011

Thanks for all the feedback guys. I got my new S&B CAI installed a few days ago and it has made a noticeable difference in EGT's (no difference in power). With that being said I think I'm going with the 3.5" DP into a 4" system from Diamond Eye. The price is great and I shouldn't lose any power with this system. Also, if I ever decide to go with a different turbo and larger injectors it won't be a big deal to switch out the DP to the 4".

jdc753 · Nov 13, 2011

yeehaw said:
i didn't at all, when i had just exhaust it drove pretty much like stock

PSM_Kid said:
I have a Magnaflow 4 inch turbo back with a 4 inch down pipe. During install, the down pipe is a tight squeeze in between the firewall and up pipes. But once it is in there, it fits awesome and does not rub on anything. The entire kit fits great, install is super easy and it sounds good too.

:whs:

The only times mine has rubbed is on the front most bolt head of the transmission crossmember. Now it is TIGHT around the up pipes and passed the firewall but I have never had any rub there. Just some minor adjustments to get it between the crossmember and trans pan. Oh and I never noticed any loss of power

Mine is magnaflow 4" downpipe.