Exhaust modification advice

[CMF_deNs]

I know i'm asking a few questions, but once I get a few things sorted I should be set for at least a little while.

Currently my stock muffler has got a huge rattle inside it, driving me insane. Probably one of the baffles inside it has come loose or something. Anyway I really need to get it replaced. The plan was that i'd eventually get a decent set of extractors and larger diameter exhaust in the end. Though my questions are:

1) How much do I replace now? Do I get piping done from the catback or should I just get the muffler replaced now, and get an adapter fitted so I can fit it onto the smaller, standard piping that it has now.

2) What size diameter piping would people reccomend getting if i'll end up getting a performance system later on?

Thanks

---dens

 

[CMF_fred]

depends what you are going to do with the engine..... (NA or turbo) and where the breakage is. Try a search on the site there has been a bit of talk about this subject late last year that might be helpful.

 

[CMF_deNs]

Thanks. I don't see myself getting a turbo setup on this anywhere in the near future but at least for now it'll be staying N/A. I've decided i'll be replacing the muffler with something anyway, so I just want to know if it's actually worth spending money for the catback or not.

Seems to be a bit of a mixed bag in terms of what people reccomend for NA/Turbo setups. Some say that 2" is too big for NA and that i'll lose a lot of low-end torque and if I go any higher, I lose even more and it's a lot less driveable.

I don't honestly give a **** about making a lot of noise, the less attention my car gets the better.

There's zero point in actually trying to repair the current muffler, and if i'm getting something new put on, I'm trying to decide wether it's worth getting it from the cat back.

---dens

 

[CMF_MRX]

My Micra's exhaust.

 

[CMF_MRX]

...

 

[CMF_MRX]

The diameter is 50mm, but i think its too big. 40mm is enaught.

 

[CMF_Snoopy]

I ran a 2in system when mine was still n/a and it was fine. Very quiet, good alround power. No real loss in low end power.

For the moment if you can afford it get a 2in cats back system.

 

[CMF_deNs]

How much would I be looking at if I were to get a 2in cat-back system? Gotta get two new tyres and still have enough for suspension gear so just trying to budget it all

Will call around a few places to see what i'm in for though.

Thanks,

---dens

 

[CMF_evade]

I'll be getting my whole exhaust replaced from the headers back, and I wouldnt expect to pay more than $350..thats just for a pretty basic 1 3/4" or 2" press bent system with cat, resonator, simple muffler..(for going back to standard)

I know a good exhaust guy and he looks after me..did my turbo exhaust too.

For a cat-back + muffler i'd be looking at around $150-200 - anything more is a rip

 

[CMF_deNs]

Just a shame you're wanting to sell your system as a whole. Your sounds so damn nice how it is currently

I don't have work tomorrow so i'll be heading out to places to get quotes and appointments for new tyres and for the exhaust.

I'll get the headers -> cat done altogether at a later date.

---dens

 

[CMF_deNs]

Actually also, considering I'll be replacing the front cat when I get new headers, is it worth it for now to just remove the secondary cat converter in the system? If not then no probs. I was going to get a higher-flow cat once I do the rest of the system, which would be under the car, rather than straight after the extractors.

MRX - thanks heaps for the pics btw.

---dens

 

[CMF_evade]

Not really worth gutting the cat in the standard headers - you dont see much gain at all from what i hear..if you are getting headers, get a VN commodore cat or something from a bigger car..they will usually work well and be cheap too . you could also open up the stock cat (which actually have 2" inlets I think..i remember posting photos of this AGES ago - maybe check the media gallery)

hehe you wouldn't want my system on your car, its 2.5" and would be too big

who knows it may get sold though..trying to sell the turbo kit as a whole has been a prick

 

[CMF_deNs]

Yeah would've thought someone would leap at the concept of turbo'ing their micra for a decent price

Anyway, I wasn't suggesting gutting the first cat at all, I've seen the article and how it's a worth not really worth doing. Was suggesting that since i've already got the front cat at the moment, that I remove the one under the car and having it straight through apart from the muffler.

If the under-car cat is 2in inlet and outlet, then i'll probably just get the cat-back system fitted onto that. Less hassle.

---dens

 

[CMF_Yom]

I fitted a 2" pipe from the manifold to the second under car cat yesterday. Needed a bit of aggressive modification considering it had come from a heavy front damaged micra. But anyway, I also gutted the manifold cat converter.

I have an existing 2" under-car cat back system with a fibreglass packed lukey style muffler.

Anyway impressions: Woah is it LOUD now. On the other hand it sounds so much nicer its almost unbelieveable. There's a rather deep rumble at idle and as you press the throttle the exhaust barks with a gruff racey tone not unlike an original Mini cooper s or GT1275. It also makes cool sounding backfire type sounds when changing gears rapidly and while decelerating using the gears.

Power past 5000rpm has really opened up. Its like a different car up there. But under 4000rpm I've lost a noticeable amount of torque. Not happy about that jan!

I think 2" might be just a bit too big for NA to be honest but I don't have extractors yet so I can't comment there. The standard manifold is shockingly restrictive. I honestly cant believe I felt an performance increase with my little modification and I find it even harder to believe anyone actually feels a performance gain with just a cat back exhaust with the standard manifold being so restrictive. The exhaust will only flow as much as the most restrictive part of it allows!

Anyway I'm not overly worried about my extra noise. It sounds really nice. I've grown up a bit lately and I don't feel the need to race around like a maniac all the time. I find myself bumbling about at my own pace quite regularly so being a bit slower under 4000rpm probably won't make much difference to my driving experience.

 

[CMF_deNs]

Intersting yom, thanks for that. I'm booked in next tuesday to get the exhaust done. Went around to several places and was surprised at some of the quotes. To get 2" piping from the cat to the back as well as a resonator and muffler I was getting quotes ranging from $220 to $320. Not cheap, but the rattle is driving me f*cking insane. Went with the place that quoted me 220, so instead of spending $90 to get a second-hand muffler I have modified to fit on, i'm spending a little more to get what would've needed to be done later on anyway.

How was it before you did the extra 2" tube between the manfold and under-car cat? In terms of sound and power differences, that is.

Ideally I'd prefer my system to be not overly loud. At the track, I don't care, but it'd good to get an idea of how it'll look when it's done. Won't have a chrome tip, not getting a cannon, just a performance muffler (y'know, one of the oval ones ). The more discrete the better.

---dens

 

[CMF_Yom]

Between the manifold and the second cat converter was just standard piping (which on my car was excellent quality stuff, just press bent and quite small in diameter). It was much quieter, had a slightly more farty note about it and low end torque was very good. It struggled to breathe past 5000rpm though.

Its actually far too loud for me. I'm going to have to get resonator or another muffler installed in the system somewhere to quieten it down!

 

[CMF_MRX]

Yom WROTE:

"Between the manifold and the second cat converter was just standard piping (which on my car was excellent quality stuff, just press bent and quite small in diameter). It was much quieter, had a slightly more farty note about it and low end torque was very good. It struggled to breathe past 5000rpm though.<BR/>
<BR/>
Its actually far too loud for me. I'm going to have to get resonator or another muffler installed in the system somewhere to it down!

Install silencer to quiet the system. http://www.autocarparts.com/parts/Exhaust/Silencers/

 

[CMF_deNs]

Has been an interesting day today. Went in this morning to the exhaust place, dropped the car off after examining the car and going over what needed to be done. Was to be a catback 2" System with a sports muffler and no chrome tip.

After that a mate of mine and I went to carrum downs to a rotary place to pick up his short shifter, then we went back to mine to install it. After doing that (took ages.. was 4pm when we finished) we cruised back to the shop.

Had a quick inspection, everything solid and all the welds look good. Went in to pay and was presented with an invoice of $280. A bit offput, he realised my shock and asked me how much he quoted me last week. I said 220. He just said "fair enough, yep" and typed up another invoice. So for a sports muffler, 2" Piping and resonator I ended up paying what I got quoted for, which was good. Walked out with a grin in eager anticipation of what the car would sound like. Idling it just sounds normal, very nice and quiet (yay!) but has a beautiful sound when rising up above around 2-3K.

Bit of a drone in the car but it's much better than the rattling that I had with the stock exhaust. I was mainly trying to determine if I had lost any low-end torque when I was driving home with it. Not a trace. When I took off from the lights, it actually felt like it had more, which really surprised me.

Either way, i'm happy.

---dens

 

[CMF_Yom]

Did you get it done from the under car cat back? Or from the first cat back?

Just from the undercar cat back you won't loose any low end torque. Lol that standard piece of front pipe and manifold are so restrictive.

 

[CMF_deNs]

Haha ok. Yeah just from the undercar cat back. Will be a while before I can justify spending more money to get extractors done as well as work out the rest of the exhaust. Must've misread, just got the impression that the system I have now would have an impact on my low-end pulling power.

Thanks,

---dens

 

[CMF_evade]

cool, wheres the pics mate?

does it look all stealthy like my straight pipe one?

<img src="http://aaronactive.net/images/photoalbum/album_7/photo_352.jpg">

 

[CMF_deNs]

Fine, i'll take some pics Rear suspension is going in tomorrow (had issues with getting the bolts of a fair bit of stuff today) but i'll see if I can take some pics now. Got brand new tyres on the fronts now, and your old ones with a fair bit of tread on the back. Much grip!

---dens

 

[CMF_evade]

hehe..get a air gun..makes light work of a lot of hard bolts

 

[CMF_SSUK]

The whole "is 2" too big" question depends totally on the quality of system you have made. I originally has a Janspeed manifold, which has an 1 3/4" collector, a Janspeed 1 3/4" de-cat box and a 2" cat back system, although the piping was 2" in the cat back, they sleeved the pipe to make it the same size as the rest of the system, so it was only 1 3/4" really.

I have just upgraded to a full 2" system. 4-2-1 header with a 2" collector, 2" de-cat box and a 2" rear system, all mandrel bent.....with no mid silencing, just a packed rear muffler. Noise is acceptable, as it's been designed properly.

It has noticably more torque now, especially between 2000-3000rpm, as well as good midrange and top end power. Certainly wouldn't go back to the old system!

Attached is a pic of the manifold for those interested.

 

[CMF_SSUK]

Another one of it after coating.

 

[CMF_deNs]

Oh stop tempting me to get my extractors done That looks great, glad to hear you're happy with your setup!

Spent far too much money on the car recently. It's just such a money drain, lol.

aaron: Well winston and I went to supercheap today 'cause he's got a compressor and we remembered how working with your airgun made life so much easier. However when we got there, the guy said that while an airgun is great for doing nuts up, we'd get more torque from a breaker bar (which we had little to no luck with). We decided to save our money for the moment and rethink things. Dunno really.

---dens

 

[CMF_evade]

lol, which nuts were you trying to undo??

 

[CMF_deNs]

Ones for the panhard rod, control arms, etc. About to go outside and give them a go again. I'm confident that we'll have them on by later this afternoon.

---dens

 

[CMF_evade]

ah yeah, the rear arms were a bitch I remember.

panhard rod wasnt though, but it is on a crap angle to get to

 

[CMF_Yom]

Basic leverage is your friend. I slip a pole over the bar and then turn gently in the direction it has to turn. Easy does it, plenty of penetrating lube like Inox/wd40 and basically every bolt on my car is at my mercy.

If you've got dodgey tools expect to break stuff because when you start using levers you put huge amounts of torque on everything and sometimes they can't handle it. Its a risk you have to take to undo some things though.

 

[CMF_Pietervdb88]

Just to throw it out there, ive got a 2.5" Hi-Flow cat-back on mine, with a 3" air intake, small switched supercharger and running on 98RON only, she flies... power-to-weight ratio is awesome no loss of low end power, PLENTY of midrange power, especially >2500rpm, just required a slight change in driving style when taking off. Still get ~500k per tank thrashing it too

 

[CMF_hotfunk67]

Pietervdb88 WROTE:

"Just to throw it out there, ive got a 2.5" Hi-Flow cat-back on mine, with a 3" air intake, small switched supercharger and running on 98RON only, she flies... power-to-weight ratio is awesome no loss of low end power, PLENTY of midrange power, especially &gt;2500rpm, just required a slight change in driving style when taking off. Still get ~500k per tank thrashing it too

Old thread revival alert.

Will let you off if you put pics up of your supercharger setup

 

[CMF_RBLUV]

^ this