Cats or no Cats?

[justi88]

So I've been thinking lately about taking off the cats and running straight pipe all the way to the rear... i live overseas so importing and o/r x-pipe is too expensive... maybe ill have a shop make a custom exhaust for my car, what is the best exhaust width to use... 2.5 inches, 3 or more???

 

[ivan12]

The best exhaust (size wise) depends on how heavily modified your is. If you don't need to do a smog check you can get rid of your cats, you'll free up a couple of horses BUT, you will get a lot more noise compared to the stock pipe, and you'll be able to smell more fumes inside the car (personal experience). Are you considering running full pipe with no mufflers? If that's the case your car is going to be annoyingly loud and I'm not so sure it's going to run very well

 

[CanaryGT]

I dont know a lot of guys who have the 302 still with a 3" or larger exhaust all the way. I run no cats, flow master 40's with an H pipe and Turn downs.... Its amazing. I have 2.5" all the way.

 

[justi88]

Have few mods but nothing heavy for now neither do i have to do a smog check, i recently took the smog pump out. Im already running with no mufflers and the noise isnt enough for me, :angry7:Ive heard a few V6 mustangs louder than me so i dont like that. A few friends that have 4banger turbos have 2.5 inch so can a 5.0 go larger or is that enough?? And why wouldnt it run well??

 

[VERT94GT]

In a word, backpressure.

 

[justi88]

mmm i read this article recently on stangtv saying there is no thing such as backpressure it all about the diameter of the exhaust... i suppose 2.5inches would be alright... the stock size must be like 2 inches?

 

[mygreengt]

i believe its 2.5

 

[CC'S95GT]

stock is 2.25.
You should be able to have a shop cut off the cats and weld in a straight pipe in place for cheap.

 

[justi88]

Ill be going to a shop tomorrow to cut the cats off and just weld the pipe in... another question Ive searching for headers and the BBK longtubes seem like the best choice the only bad side is the shipping and customs to my country shoot the price up like to 1000$... i think shortys would be the better choice but type is better the equal or unequal??

 

[CC'S95GT]

You'll most likely not see a performance difference between equal and unequal length shorty headers.
The unequals are way easier to install. they just don't look as cool as equal lengths with all the twisties.
If you go with the BBK's and your car is going to be any kind of show car get the ceramic coated. The chrome ones are built with the straight tube chromed first then the tube is bent and welded. Soo you have all of the tooling marks in the chrome and the chrome shows cracking where it is bent.
I also had lot of extra fat weld bead inside of the tubes which would have restricted the exhaust flow if I hadn't ground it out.
I just thought you should know what to expect if you got the BBK's.
Overall I'm satisified with the performance of the headers just not the finish. but you get what you pay for.

 

[justi88]

my stang does go to casual show but mostly for 1/4 mile.. i thought BBK was a good brand and had excellent quality i already have CAI, MAF sensor and UDs from them. I havent found any cheaper so i might go with BBK or is there another brand thats worth investing my money??

CC'S95GT how did you ground the extra weld??

 

[wannaboost94gt]

JBA Equal shorty headers, O/R H, 2.5 pipe to spintech glaspack turndowns. :thumbsup:

 

[CC'S95GT]

I used a pneumatic die grinder with a rotery file installed.
The extra weld material inside the ports was about 1/8-3/16" all the way around each port.

The chrome headers are good looking and once installed you can't really see the tooling marks anyway. They start turning blue right away also. as any chrome header would.

The ceramic coating has to be applied after assembly so the finish is much better.
For the price they are a very good header.
I just thought you should know everything to expect before you put down the $.

 

[justi88]

The JBA headers look nice but to expensive and out of my price range.... i want to get a set that's not to pricey but good quality and performance, the ceramic coated bbk headers seem to be the best choice. I saw a picture of some guys chrome bbk headers and they were all rusty and i don't want that. I like the twisties also in the equal headers :grin:

 

[ivan12]

I've seen a couple of dyno graphs were the equal length loses a horse down under and picks up two up top. Not really worth it in my opinion as my bassani equal length were a pain to install. There's less bolt clearance and I had to raise the engine quite a bit in order to massage them in. You can't go wrong with the ceramic coated bbk unequals

 

[justi88]

Ok ill go with BBK unequals... from there ill make a custom pipe all the way to the back and im thinking making it 3inch... my friend has a 1.3 liter starlet gt turbo (Toyota Japanese Car) and I saw his exhaust and its 3 inch straight pipe so i guess a V8 can also go 3 inch

 

[wannaboost94gt]

equals not too hard, also 3" is too big for a near stock mustang...

 

[T-5 Killer]

stock is 2.25.
You should be able to have a shop cut off the cats and weld in a straight pipe in place for cheap.

+1
3 inch is way to much on a near stock 5.0 you will lose a ton of low end.

 

[VERT94GT]

The reason you need backpressure is for scavenging. Turbo cars are diff. The exhaust needs to be routed out and not, well, swimming around in a 3 inch exhaust. If u ran pipes with no cats or mufflers with 3 inch pipes to the back, well, what T-5 said. I'm no expert but that'd be a lot of space for not so much exhaust until WOT.

 

[justi88]

:dontknow: Sorry I'm not to familiar with some english words so what is scavenging?? From what everyone says 2.5 with be the best setup so I'm going with that one and also going with the BBK unequals.