Paradise Racing

I need to buy a new exhaust system and was going to go with a 4" until I saw that there is a 5" for $40.00 more.

Is there any advantage or disadvantage to the 5" system?

Any opinions?

Thanks in advance.

4doogie

my understanding is that if you dont need 5" dont get it. i also recall someone saying you might lose power. if your running 5,6,7 hundred hp then its what you want other wise a 4" or just strait pipe what you have. i have a 4" turbo back system in my future just my .002

crobtex

That's what they make 5" tips for.

Mark Craig

Paradise Racing,

Unless you get into 500RWHP levels the 5 inch won't get you anything but a real strong diesel sound. The 4 inch systems are all 95% of the folks need unless they just want the louder sound. Check our site and or call us as we have aluminized, 409, and 304 in single 4 inch and dual 4 inch systems, we also have 5 inch system but sell very few of them as they just aren't that popular etc.

Mark @ DPPI

Forrest Nearing

5" = sounds awesome, looks tough, and gives you room to grow (who is ever "satisfied" with their power level!??!?! )

Paradise Racing

Hey guys, thanks for the advice. I ended up doing a 4" Bully Dog system and it worked out very nice!!!

It feels like the truck picked up some mid to hi end power.

Thanks again!!!

98rammer

blah, once you see a couple hundred trucks, 4" becomes puny, and 5" is ok. now my 5" looks kinda small...6" tip maybe?

**If you want a 5" exhaust, GET a 5" exhaust**

erics76

Yeah, I agree. If you want the 5, get it. When I put mine on, I could tell I lost a little down low, but it picked up alot more in the mid and high. Everybody's got a 4 inch system. When you see a 5, you have to look again because it's different. Did I need a 5? No, but I got it cheaper than 99% of the 4's, and wanted something different.

HOHN

The only reason I could see going to a 5" is if you plan on running twins-- where the large charger has a 5" outlet.

But I'd be willing to bet that necking down to a 4" from a 5" outlet might not give you much of a hp penalty.

Keep in mind that the bigger you are, the more 1" means. For example, going from a 1" pipe to a 2" pipe gives you a decent increase. But a 3" is a much larger increase over the 2" than the 2" is over the 1".

Thus, the increase from 3" to a 4" system almost DOUBLES the exhaust flow..

The 1" increase from a 4" to a 5" is a HUGE increase compared to the 1" increase from 1" to 2" pipe.

Cross sectional area:
3"=7.06 sq in
4"=12.56
5"=19.63

Justin

joefarmer

Hopefully Tim(InVa) can speak more to this, but I think the 5" outlet to 4" exhaust restriction was part of the reason he was stuck around 540-550 for sometime. Going to a 5" & different housing was worth something more than expected on the dyno. Tim -- did I get that even close to right?

brandon.

HOHN

This is something that I'd like to know, too. Logic seems to say that necking down anywhere in the exhaust is bad for power. If you change diameter, it should only get bigger, right?

Moose10

Anybody running an exhast brake with their 5" system? If so, what kind, and how is it installed?

duke1n

Volumn and diameter have an exponential... remember pi*r^2?

r^2 being the important thing to keep in mind. Hence the area...

4" - 3.14 * 2^2 = 12.56"
5" - 3.14 * 2.5^2 = 19.625"

So small increases in diameter produce large increases in area. I wish I would have went 5"... my straight 4" is just too quiet lol.