The truth about 3inch exhausts on Na Cars

[7MA61]

Slightly more power across the board, will post both sheets and a quick vid later. Err the 3inch in farking loud though, like race car loud, fucked my tune massively too. So probably more power in the 3inch with some tuning:icon_bigg.

Old system was FGK Fujitsobo extractor into 2.5inch cat into 2.5 inch press bent into 2.5 inch straight through muffler.

New System, same extractors, 3 inch cat, 3 inch mandrel bent system and 3 inch straight through exhaust.

 

[7MA61]

http://bebo.com/watch/4408177514

http://bebo.com/watch/4408210922

Vids:icon_bigg

 

[balong]

nice. effing loud lol

 

[ValgeKotkas]

Yeah, and what's below 60kmh?

 

[s383mmber1]

Very good info! Proves my, and lot of peoples points here

 

[7MA61]

^^^ Indeed I was worried about losing some bottom end but nope. I have scanned in the graph, its amazing how much the 3inch has fucked up my tune though. Leaner which is good but its all over the shop. Notice also that it was wound out to 180kmph on the dyno this time which suggests its holding in the topend alot better too.

Old Graph:

New Graph:

In saying this I wouldn't rush out and throw a 3inch on your NA because it makes more power, my car is now so loud you could probably hear it 2 miles away at full throttle. But I only drive the car on weekends to have some fun and in motorsport, not the kind of exhaust I'd put on a car that does alot of driving unless you were to throw a proper muffler on and possibly alos a resonator.

 

[Ma70.Ent]

Now I wish someone would post a 2.5 inch vs 3 inch. Oh well, this will suffice. I'm going to sticky this.

EDIT: Yeah, I just reread the first post. Don't point out this post's error

 

[BorHor]

Hmm so I was right.. oh well.. I couldn't stand the super loud sound.

 

[JustAnotherVictim]

Now I wish someone would post a 2.5 inch vs 3 inch. Oh well, this will suffice. I'm going to sticky this.

Read it again bud.

Old system was FGK Fujitsobo extractor into 2.5inch cat into 2.5 inch press bent into 2.5 inch straight through muffler.

New System, same extractors, 3 inch cat, 3 inch mandrel bent system and 3 inch straight through exhaust.

You mean both of those compared to stock maybe?

 

[balong]

yeah. my 3 inch is overly loud
wasnt my choice tho. bought it like that
i can live with.

 

[s383mmber1]

Now I wish someone would post a 2.5 inch vs 3 inch. Oh well, this will suffice. I'm going to sticky this.

This is compared to a 2.5 inch i think.... Read his post again!

 

[Fuzz420]

Very interesting information. Im currently running straight 2.5 inch piping with no muffler and i believe its just as loud. I also believe my muffler was on the restrictive side, b/c after it fell off the car felt stronger. Also after i dyno'd it again i gained 7whp, and 9lb/tq.

 

[Big Wang Bandit]

3 liters isn't a small engine size. I never thought it needed that much back pressure.

 

[Doward]

No engine needs backpressure - you want to ensure you have enough velocity to get the exhaust out, without causing any rise in pressure.

That said, I'd like to see this 3" mandrel compared to a 2.5" mandrel bent system.

 

[AF1JZ]

Honestly, is a couple more hp worth having a loud ass exhaust?

 

[BorHor]

Honestly, is a couple more hp worth having a loud ass exhaust?

Not to me thats why it is gone to a car that can actually use it.

 

[Ma70.Ent]

JAV/s383, I just reread the post. Doh

 

[IJ.]

Be interesting to see a Db test on this one
(My 3" was 97Db even with the Turbo)

 

[akito]

would it be louder or not if it is just only a catback 3inch because im about to get one from my cousin when he put on his new system.

 

[BorHor]

^ It will be loud.