Jump to content
SAU Community

Recommended Posts

imo, what does 3m of 2.5" pipe have to do with it when in the end its just into the atmo,

i mean basically having say 4" full exhaust (just to make it plane obvious) thats basically the same as the air being dumped straight into the atmo.. i dont get how it could be easier to have air "sucked out" when it all ends up in the atmo in the end.

  • Replies 98
  • Created
  • Last Reply

Top Posters In This Topic

Just opening up the exhaust is not necessarily the answer. The extreme would be to remove the exhaust system altogether but, for those of you who have experienced it, if the exhaust breaks near the manifold, all power is lost.

For a normaly aspirated (non-turbo) engine in particular it is important to retain a certain amount of back pressure. The reasons for this are all to do with exhaust scavenging which is to do with negative pressure pulses reflected back up the exhaust manifold to remove the last of the exhaust waste from the engine.

Hi [D4RKS1D3],

How much it set you back? Which one is it from this list..

http://www.magnaflow.com/02product/shopdis...one=main&id=386  

Anyone know whats happening with that group buy?

cheers

chicane

http://www.magnaflow.com/02product/shopexd...one=main&id=764

Thats it there. cost about 450 for the muffler, and about 300 for the rest of the install. i do however have a feelin that i got a bit ripped off on the price of the muffler, but i didnt realli mind cuz the bloke rushed me thru and had it all installed in a couple of hours the following day.

The group buy has fallen thru i think. Not enough interest and communication problems with the supplier i think.

my car had an HKS dual dragger when it was imported, far too big and far too loud - absolutely useless, it was more suited to a GTR or GTST...

needed to change it for compliancing so I had a stock exhaust put in (still have it today) and the stock exhaust sounds absolutely CRAP, but it definately isnt quiet.

illusiVe - I've already posted a link to this site in this thread http://www.miata.net/garage/KnowYourCar/S4_Back.html Go and read it and learn all about scavenging

As for my muffler, I have a universal, large bodied, mild steel, 2.5" straight through muffler. Cost me $110 fitted and have proved (on the dyno) that it produces the same amount of power as my old TRUST muffler.

Have spent sometime reading throught this thread, as I have been thinking of changing my current exhaust, to a more straight through system. Currently I have jasma approved system with extractors (6,2,1), 2 1/2" stainless exhaust system with no cat and two very large mufflers (not the straight through sort). I was thinking of putting in a couple of resinators and a straight through type muffler, in the hope that it might improve the flow of exhaust gasses.

A friend sent me this article which I found quite an interesting read, looking into the importance of exhaust gas flow and looks into the back pressure thing too.

what size is the standard NA exhaust?

Mine was 2 1/4 inch from the factory i think. So basicalli you open it up 1/4 of an inch when movin to a 2.5 inch system. The onli thing that realli holds back your exhaust is the mechanical(?) muffler which is meant to baffle sound via redirecting exhaust fumes.

i think thats what the standard muffler is called. It just has the air looping back and forth thru a series of tunnels. if that makes any sense. where as a with a straight through muffler, its just a straight tunnel.

_________________

| _______________|____

| ( __________________ <-----exhaust

|_(____________ ) |

_______________) |

|________________|

In a standard exhaust then the fumes are "baffled" through a "mechanical" eexhaust and this results in restrictions.

__________________

| |

|_________________|__

____________________ <----- exhaust

| |

|_________________|

In a straight thru exhaust their is no restrictions to exhaust

nice ascii work [d4rks1d3] hehe.. ;)

check http://auto.howstuffworks.com/muffler3.htm ppl.. some go around in the fashion like d4rk mentioned, some go thru a more 'inline' series of sound absortion material/chambers etc, but the gist of it is the same.

I spoke to an exhaust shop (perf exhaust in ringood) about a muffler today. I told him how I want to go to a quieter (ive got a noisy rev-flow muffler on there now, and 3" pipe from bends to the muffler) one and he said a canon style (round) won't be the ideal one. He recommended an oval style one. Also quoted about 380 for a maganaflow oval one, but im not thinking only maganflow, but any good brand (post if you can recommend) which will quiet it down a bit, but not strangle it (and have _some_ noise when on the throttle).

Cheers :D

chicane

  • 2 weeks later...

anybody else care to reply to this thread and mention anything I should look out for when getting a new muffler on my R33?

Cheers,

chicane

------------------------------------------------------------------------------------------------

An internet forum is only as good as the quality which is contributed..

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Thanks both. All good advice. Reminds me of drilling through stone wall for drainage pipe 😬 I'll let you know how I get on if I still have use of my hands afterwards 😅
    • Finally got shipping number for the intake and throttle body, shipped by UPS, so "should" be in my hands sometime next week, fingers fracking crossed
    • I'm so far behind in the jobs I have to do at both work and home (including car) that I have become immortal. There's simply no way that I can die now.
    • Each to their own I guess  Me, I put just as much time into cleaning inside of the cars as I do on the outside As for getting wet, it is really no different than steam cleaning the carpets at home, apart from the cars carpet dries alot faster than the house, again, I only do it in the hotter months and leave the car opened up for a few hours As I only do it yearly, it is just before I do the diff and gearbox service, so I clean the carpets, then it's up on stands, wheels off, service, clean the undercarriage,  grease the bushings and do a nut and bolt check on everything  Disclaimer: I typically had all the time in the world to kill when I was working 🤣, so spending a full day or 2 cleaning, serving and "looking at stuff" was,  easily achievable, and a fun mental therapy day As for time to kill, I retired last Wednesday, so apart from my physical training, my days are filled with lots of random jobs around the house and garden...."Idle hands are the Devils something something" I am also buying a new house sooner rather than later, I'm actually looking at a potential property tomorrow, I'm looking forward to getting a car hoist as I'm starting to get to old to crawl around under a car, I can only imagine all the undercarriage cleaning and looking at stuff when that gets set up
    • Yeah, I'm not interested in wetting the carpets, and I don't care about brown dirt/dust that lives deep in the pile or underneath. It's not like I crawl around on them in my birthday suit or eat dropped food off them (because there is never any open food in my car). The seats are alcantara (cheap Chinese imitation alcantara, to be sure!) with barely 1" of foam pad behind the surface. That's not getting wet either. Any car that I would be happy to get the interior wet, I would not care to put the effort into.
×
×
  • Create New...