just curious, i have 3" right now; but i'm replacing my engine with something better hopefully soon here. i'd like to be good for up to 600 range.

 

If you had done a search, LOL j/k

irocztwentygr8 posted this a few days ago, off of a website.

HP-------Single----Dual
200-300----3"------2.25"
300-400---3.5"-----2.5"
375-450----4"-------3"
450-550---4.5"-----3.5"
550-650----5"------3.5"
650-800-------------4"
800-1000-----------4.5"
1000+---------------5"

 

thats going to be one big pipe

 

you have to be kidding..........i'm not running that size pipe on the car..

i've got that on my diesel and it's laughable large, i'll look like a lowrider shooting sparks down the blvd.:lala:

 

But NO ONE would tailgate you

 

Well, get the biggest pipe you can fit in their.

 

i know, i just hate the thought of it looking out of place...

 

Stay with the 3" pipe...

 

Does anyone remember the metalic blue 91'-92' Z28 That was built by a magazine a few years back? It had a 420 with a super ram, Tremec T-5, etc. It ran into the 10's with a 3" SLP 2OL system IIRC. I wouldn't dump money into a larger exhaust until you have some sort of dyno proven proof that a 4" system will make enough of a difference to warrant the cost.

 

Whooop there it is. Those numbers up top seem wrong to me. I've seen plenty an F-Body in the 11's with a 3" catback. Have also talked to an LT1 guy running low 12's with AFRs and a 224 cam who tried both a 3" and a 4" catback. No difference in ET between a 3" uncorked borla and the Mufflex 4" catback.

Tim

 

That's what I thought, I could have sworn 3'' single could support more than that HP, thus making the rest wrong, but I just copied and pasted what someone else did.

someone do some research.

 

I've seen that information before. Isn't it from Flowmaster

 

I dont know who the info is from or how accurate it is, but even if it is acurate it wouldnt be how much power you could make, it would probably be how much you could make without a noticable loss or something to that extent. I mean you could make a **** load of power with a 2.5 exhaust if you did enough stuff to a motor, but when you upgraded it your power would go through the roof.

Ben

 

I believe that chart or any chart for that matter, is based upon what HP there will be a restriction, so let's say you have about 400hp and a 3'' pipe, according to that chart above, you'd create more HP with larger pipe , so it won't be choked off.

 

I went from a 2.5 inch custom y and a full 3 inch single exhaust to a custom 3 inch y pipe and a full 4 inch exhaust this year and it with no word of a lie picked up close to a second on my et. I ran 13.9 with th old exhaust and then ran 13.20 without changing anything but the exhaust. So in my opinion it makes a huge difference.

With regards to hp ratings I know 3 people in particular that have small block chevys in the place I live in that run low tens and high nines with dual three inch exhaust.

So if the chart is right in saying that a single four flows as much as dual three inch, one can expect to go fairly fast with a four inch single pipe.

Keep in mind I'm not using a cat back system by mufflex buta full four inch single from the cat back.