Question for everyone with a 3" exhaust

viperboy · 10-18-2009, 02:10 AM

How do you guys do the piping? I have OBX headers and I want to run it like this... header > 3" electric cut out > HFC > 3" exhaust but my question is how do you make the 3" and the 2.5" from the headers bolt up? I haven't been able to find a 2.5" in 3" out cutout or anything like that. Could someone give me an idea as to how to run this setup?

Professor · 10-18-2009, 12:25 PM

Sounds fun cant wait to see and hear final product.

kzoosho · 10-18-2009, 01:47 PM

Well you could always just get a 3 inch pipe welded to the 2.5 collector. Problem solved.

viperboy · 10-18-2009, 08:46 PM

Quote:

Originally Posted by kzoosho

Well you could always just get a 3 inch pipe welded to the 2.5 collector. Problem solved.

Sorry to sound like a complete idiot, but how would that work since the sizes are different?

shadyonedeath · 10-18-2009, 10:00 PM

Quote:

Originally Posted by viperboy

Sorry to sound like a complete idiot, but how would that work since the sizes are different?

Cut the 2.5" off the Headers and weld a 3"....just like he said.

kzoosho · 10-18-2009, 10:21 PM

Quote:

Originally Posted by viperboy

Sorry to sound like a complete idiot, but how would that work since the sizes are different?

its been done everywhere. You can take the 3 inch pipe slide it over the 2.5 and weld the gap up or cut off the collector and weld a 3 inch in. There are options.

viperboy · 10-19-2009, 05:00 PM

Got it, thanks for all the input guys. I've decided to do a 2.5" electric cutout and maybe change to a 3" exhaust later on down the road. Local shop wants 200 to install the cutout, weld the flanges, move the cat and resonator back and run the wiring. Is that decent?

viperboy · 10-19-2009, 11:30 PM

viperboy · 10-21-2009, 06:58 AM

Where did you guys all go?? Just wanna know if 200 is reasonable to have a shop install it or not.

TeH BawNeY · 10-24-2009, 07:08 AM

Quote:

Originally Posted by viperboy

Where did you guys all go?? Just wanna know if 200 is reasonable to have a shop install it or not.

No, I had mine welded in for $40.

kzoosho · 10-25-2009, 06:46 PM

I do all my own welding so i have no idea what i shop will charge you.

*DrunkieTheBear* · 10-25-2009, 07:15 PM

Quote:

Originally Posted by TeH BawNeY

No, I had mine welded in for $40.

$40 for what, welding on a muffler...

$200 is resonable if they are using their piping and such, I had my 3" done for $250

viperboy · 10-25-2009, 07:42 PM

Quote:

Originally Posted by DrunkieTheBear

$40 for what, welding on a muffler...

$200 is resonable if they are using their piping and such, I had my 3" done for $250

Sorry Drunkie, maybe I didn't explain right. They want $200 to just install the electric cutout and move the cat and resonator back and get the wiring for the cutout into the cabin.

A 3" exhaust would cost me alot more than that around here. I don't know why, but shops around here are expensive.

nismo_star · 11-01-2009, 03:51 AM

only time I used 3.0" was on turbo application, complete turbo back.

3" to 2.5" reducer: http://www.amazon.com/gp/product/B001804SEA

*maxgtr2000* · 11-01-2009, 05:17 PM

I think muffler shops charge like $60-75 an hour depending on the shop. I got ripped for $150 for them to weld 2 flanges and a 12 inch long pipe with a bend to join my down pipe from the turbo to the rest of the exhaust. I think $200 sounds about right for what they have to do.

bryan163 · 11-01-2009, 08:52 PM

Putting a 3" exhaust on an N/A Maxima will add weight and reduce horsepower.

viperboy · 11-01-2009, 10:09 PM

Quote:

Originally Posted by bryan163

Putting a 3" exhaust on an N/A Maxima will add weight and reduce horsepower.

How about reading up before posting? They have proven there are gains to be made with a 3" exhaust. Jay_pee has one as well as other mods and runs high 12s ALL N/A.

And I'm sure it's faster than your turdbo 4th gen

bryan163 · 11-01-2009, 10:42 PM

Quote:

Originally Posted by viperboy

How about reading up before posting? They have proven there are gains to be made with a 3" exhaust. Jay_pee has one as well as other mods and runs high 12s ALL N/A.

And I'm sure it's faster than your turdbo 4th gen

I'm not familiar with his car, but if he is running 12s he must be making enough horsepower to justify an exhaust that size. Thanks for setting me straight on that one. Now as far as being faster than me, well thats even more unfounded than my claim. Either way my advice is correct for the car in question. Now let me explain why it will work for his car and not for yours.
I have done my reading, not to mention testing and fabrication. I am running a 3" exhaust, but only because I am in the 400hp range and moving a huge volume of air. In N/A applications your exhaust makes best power by maintaining a negative pressure wave in the exhaust system which draws the spent gasses from the combustion chamber as each valve opens. For this to happen, moderate exhaust velocity must be maintained. A 3" system would have such low exhaust velocity that no scavenging could take place. Not to mention the added weight.

*DrunkieTheBear* · 11-01-2009, 11:44 PM

Your not bringing proof to the table...just what you say.

On the org here are SEVERAL dyno's on different cars, showing gains on the low, mid, high.
Stock, lightly modded, and heavy modded....all power gains. Dyno's are readily available when you search

bryan163 · 11-02-2009, 12:20 AM

Quote:

Originally Posted by DrunkieTheBear

Your not bringing proof to the table...just what you say.

On the org here are SEVERAL dyno's on different cars, showing gains on the low, mid, high.
Stock, lightly modded, and heavy modded....all power gains. Dyno's are readily available when you search

I've experienced the opposite in cars I've actually done exhausts for. Top end was improved by going 2.5" with some compromise at low and mid rpms. I would never push it to 3" on an N/A car. That is also the reason why manufacturers of performance exhaust dont make them that way. What are these dynos in comparison to?

nismo_star · 11-02-2009, 05:24 AM

too many variables, if you've 'done' exhausts.

Alot of performance companies make 3" version of exhausts. We had prototyped GReddy TiC 3" models on several NA cars, with heavy breathing mods, which eventually were brought to market.
SR20VE powered Sentras need 3" to breathe correctly. K20A2 powered Hondas need 3" exhaust to breathe correctly, esp with heavy mods.

*DrunkieTheBear* · 11-02-2009, 07:45 AM

Quote:

Originally Posted by bryan163

I've experienced the opposite in cars I've actually done exhausts for. Top end was improved by going 2.5" with some compromise at low and mid rpms. I would never push it to 3" on an N/A car. That is also the reason why manufacturers of performance exhaust dont make them that way. What are these dynos in comparison to?

2.5" vs 3" exhaust.

I'm not searching, I've explained this time and time again and have converted how many people from saying "omg you can't do 3" exhaust" to "HOLY CRAP look it the gains you got across the entire rev band"

I'm not explaining this **** anymore cause I'm tried of thickheaded people not wanting to get rid of myth's....thats all you go on....myths

*DrunkieTheBear* · 11-02-2009, 07:49 AM

http://forums.maxima.org/6911918-post8.html

THIS IS THE LAST TIME I EVER EXPLAIN THIS

nismo_star · 11-05-2009, 07:38 AM

lofl simmer down dude

Majestic Ken · 11-08-2009, 11:35 AM

i say just keep the electric cutout (which 200 is a pretty reasonable price) and dont waste more money getting 3 inch later cuz its the same thing. you running the version 2 obx? I'm gonna get these soon. i was thinking about doing the 3 inch exhaust myself. it will cost around 175 here

nzelinsky · 11-11-2009, 12:10 PM

3" ftmfw!! Im pricing a custom setup right now