How much HP does a straight exhaust/aftermarket exhaust gain?

[85_305]

I saw on MBRP's website they advertise like 25hp and 53lbs of torque from putting their 4" exhaust on. Is that true?

I've heard there is VERY little difference between a factory straight pipe exhaust, and a 4" exhaust or bigger until you hit like 400hp or so, and about 25-50* egt differences

[layson]

I don't think you really gain anything until you get a chip. It is pretty much a supporting mod.

[85_305]

Thats exactly what I thought. i mean, I can understand factory exhausts hold lots of backpressure etc.. but they are advertising numbers on their site.

What would the HP differences be between a truck w/ a straight exahust or a bigger exhaust and a chip, and a stock exhaust plus a chip?

[GM Duraturd]

Not to much of a gain. Not noticable, besides sound. Definately a necesity with a chip, etc.

[85_305]

I wonder why MBPR advertises such numbers then

[layson]

Don't know... the AFE stage II claims like 50 horsepower...

[85_305]

what lying bastards. ah well. I didn't believe them, quite the opposite in fact. thanks for clearing that up guys

[blowinsmoke7.3]

I gained 26.3 HP after installing my 5" system and another 16 with the stack
Not really
Come on guys you all know why all these companys are putting #'s on there products...SALES!!!! I would do the same thing if i was them

[Fordnut74]

I can tell you from personal experiance that once you stright pipe your OEM exhaust you will not see any real gain from an aftermarket exhaust until you are close to 400hp. However if you go from a Factory muffled exhaust to an OEM muffled exhaust I can absolutely see 25hp. The Factory muffler is very restrictive.

[sleepy]

I have a completely stock truck and I just installed a 4" turbo back aluminized exhaust. I felt like I lost a little a low end power. I didn't dyno it and I can't say for sure. I plan on a intake next followed by a chip. I was trying to get my truck breathing good before installing the chip. I also saw the advertised gains for the exhaust and was dissapointed. I am new to diesels and trying to learn myself. Hope my input helps you with your decision.