[future_psd_owner]

i have an 03 and am getting a 4" system installed tommorow and the muffler guy is telling me that 4" tbe, mainly the dp, is bad for the turbo. it will be straight piped. anyone with problems on a 4" tbe straight piped on an 03 6.0? should i go 3.5? all ive got is afe intake. no tuner.

 

[martyyeager]

The only problem I had with the 4" downpipe was that it would not fit. I have the manual transmission, and I hear that there is a tighter fit vs. the auto tranny. The 4" pipe would not fit, even with cutting out part of a "flange" along the firewall to clear the downpipe. The 3 1/2" downpipe barely fit along the firewall.

 

[OldFlick]

I had a '03 for 48k miles and a 4" turbo back and engine never had any work and full Blackstone oil reports w/o any problems. It was a great rig(still is for new owner).

 

[HeavyAssault]

You may find a drop in the low end power during take off using standard pedal. If you build boost while at a stop you may find the take off quite exciting.

Look into a tuner shortly after the exhaust install.

 

[legends14x]

my bully dog exhaust is a true 4" turbo back system. I believe it is one of the only true 4" systems. Most other D/P's are 3.5"

 

[OldFlick]

Hog exhaust if a true 4" system, except for the 5 1/2 tip.

 

[chadcma350]

i got my 4in dp from hog back in 04 and i had to do some ball peen hamer and torch work to the down pipe to prevent it from rubbing i just had to heat it up and tap on the dp just a little to get it to fit past that body seem,but was worth the extra work to have a full turbo back 4 inch system.

 

[Bullrack]

I tried both 3.5" and 4" on stock, slightly modded and heavily modded. The 3.5" outperformed the 4" in every scenario. Plus, due to the torque of these engines with the 6spd., the 4" "WILL" hit and rattle at various times such as hard launches and tight turns. This is just my observations with my truck. The 4" seemed to make my already terrible low end lag even worse, no matter what mod I made. I also have a friend running a 4" DP on his regular cab wihtout any of the problems I experienced. I guess his truck does not flex near as much as mine and is auto. His engine also seems to like the 4" alot. I know this info doesn't really answer your question as to which is better, but if you want the 4", try it and live with the effects whether good or bad, or change it to 3.5" DP. It's almost hit or miss, but as a rule of thumb, the 4" makes low end very sluggish.

 

[OldFlick]

The '04 has more turbo vanes that the '03 & the '05 has more than the '04. This will make more low end power and that might be the difference. Had a '03 w/4" and it lacked for nothing. Ordering a 4" Hog system for my '05, will be interesting. I have put three 4"downpipes in and one had a ton of room and one sucked(pushed entire floor up for room).

 

[future_psd_owner]

well i think im going with a 3.5" dp and 4" striaght pipe and 6" tip. i bought the truck with an afe intake and nothing else. contemplating a tuner. i think i bought one of the last "good" 03 6.0's. ran an oasis report with the dealer and said it was in for no major service. just a sticker under the hood that says pcm reprogram. truck runs excellent. just cant wait for that straight exhaust sound /ubbthreads/images/graemlins/smile.gif thanks for your help/input guys...

 

[Mark Craig]

oh3_6oh,

Do yourself a favor get a system like the MBRP or AFE, they have 3.5 inch down pipes. The VRT turbo doesn't get any benefit or EGT drop from a 4.0 down pipe anyway. Not to mention the install hassles and or the potential for the DP to hit the firewall when towing and the engine torques over etc. If you have any questions call us, we have been selling 6.0 exhaust before anyone as the original MBRP systems were built on my 6.0 truck!!

Mark @ DPPI

 

[future_psd_owner]

can you beat $475 installed? im looking for more low end torque. i really have to lay into the pedal to go. any idea on reducing turbo lag? anyone have their vgt turbo "ported"?

 

[Mark Craig]

oh3_6ohm,

Can't help you with installed as we don't do installations and your most likely far away etc. But the prices we have can get you a system that will allow you to get it installed locally for that or less! Call us and we'l get you the various prices for the different systems, they start below $300.00 as a beginning!

Mark @ DPPI

 

[future_psd_owner]

sorry. stuffs ordered. i get it installed friday. but ill keep you in mind. i like your persistance.

 

[midnightsmoker79]

I run a magnaflow and i have been very happy. magnaflow now offers a cat adapter kit for the stock cat ($50) and there low end XL system is stainless steel (not polished). they have 3.5 and 4 inch down pipes aswell, duals and even 5 inch. cost for the 3.5 dp to 4 inch is about the same as everyones else. i got mine for $399 for stainless.