Making upgrades to the exhaust system (newbie alert)

[tjongster]

Hi guys !
recently join the mx5 car talk forums !
i own a '00 NB8A stock with exception of bc coil overs
have had the thought of doing some performance upgrades to my car mainly the exhaust system to gain some performance boosts and also sound beefier and just better overall.

however im new to this and not sure what or where i have to go to get it done.
im located in brisbane
have read about mufflers and headers, qsn is do i have to change both or is either going to make a difference to the car ?

Thank you for your inputs ! much appreciated !

[hks_kansei]

The NB8A system is made up of 3 sections.

Headers (also called extractors) these are the ones you see under the bonnet, 4 pipes (one for each cylinder) that lead under the car where they join together into one pipe.

Next in line is the midpipe, which bolts to the headers. On the NB8A the midpipe consists on the catalytic converter, a length of pipe, a small muffler/resonator. the midpipe ends at the rear wheels.

After that is the muffler, which bolts to the midpipe.



On their own, and without any other mods (mainly ECU stuff) don't expect any huge gains in power, maybe a couple of kw, but don;t be shocked if there's no difference.


If the main goal is sound then the muffler is the easiest to do, you can either buy a pre-made one ready to bolt on, or have an exhaust shop make one (usually you just choose a muffler and they'll weld on the fittings and pipes to make it fit the car.

If you buy a pre-made one i'd suggest installing yourself, it's a simple job of 2 nuts and then prying the rubber hangers from the exhaust (give them a spray of lube to help the rubber slip off easily)

[Mr Morlock]

My previous experience with old cars and rusty and corroded exhaust components is that it can be a misery to remove parts and get good access. Exhaust shops have all the right gear and know how and do jobs much quicker than a DIY.

[hks_kansei]

When I did mine the first time all I needed to do was give the bolt head, and the threads sticking out of it, a quick rub with the wire brush (clean rust/mud/etc from the threads), a squirt of WD40 or whatever penetrant you prefer, wait a while and then crack them with a socket.

You'll likely need more leverage than a normal socket can provide so simply slide a small length of pipe over the handle and use that as an extension.
Of course, if you've got a long handled breaker bar then use it, but I understand not everybody has one on hand (I can recommend the investment though if you're going to work on cars, it's worth every penny)



The other cheating method is to position the ratchet so the handle is horisontal and put a jack under the handle and slowly lift the jack up. Don't lift it too far, if the car starts to lift then stop. you should only need to lift the handle a little until you hear a loud crack sound which indicates you've broken the bond the rust can form. After it's cracked you should be able to do it by hand.

The breaker bar/extended handle is a better option though, since it's safer, and you can feel if the nut it starting to round off and stop before it's ruined.



edit:
I'm talking about the rear muffler bolts here, which are easily accessed, even with the car on teh ground.
If you're replacing headers etc it's quite a lot more annoying.
Doable, but don't be shocked if a few studs break etc.

[tjongster]

thanks kansei for shedding light on the exhaust systems of the nb !
if the exhuast awont make such a difference in terms of performance should i proceed with an ecu tweak as well or another upgrade should be set in mind ?
i do however would like a better sounding mx5 hhahha

[tjongster]

I'm actually just looking for ways to improve the performance and sound to my daily drive car

[hks_kansei]

Sound wise the muffler is the most cost effective, and the simplest.
An air intake is another option for sound, of course you can do both together.

At the moment I have an intake on mine purely for the sound, I used to have a loud muffler on there, but I sold it since I found I wasn't actually enjoying the car while I had to constantly look for police cars. In saying that, the muffler I had fitted was a lot louder than most.


I'd suggest the intake and exhaust, since they're cheap (my intake set me back I think $60 or so) and the exhaust depends on what you get (secondhand is a great way to get cheap, good, mufflers)

those two will sound good, and give the car a little bit more poke, but it wont be a night and day difference.


ECU changes are the way to go for decent power, but they very much depend on the tune. A good tuner can get a bit more power out of a stock car (Mazda's tune is a fairly generic one to be safe for all fuels etc)

bear in mind though that the cost of an ECU and tuning is pretty high. Generally unless you're also doing other large mods (turbo, big cams, supercharger, etc) it's not worth the cost.

[rascal]

Simple rear muffler change will definitely tick the better sound box, not so much the more power box..

[StanTheMan]

My suggestion would be

do the full exhaust & intake system. If you are planning on staying NA go for a 2 1/4 system. But also get an enlarged air intake system.

I have the Mania CAI which by itself gives you fantastic sound through the front. It will not be too audible to the outside.
Once you modify your exhaust it all depends on what system you decide on.
I have pretty much what I described above with the full enlarged air intake with headers & larger exhaust. To the extend that my air intake now is inaudible as everything else is much louder.

I think this would probably set you back around $1.5K-2K? but it all depends on if you get your bits new or 2nd hand. You could then add cams if you want....but that's getting a very slippery slope.....I recon Dan will tune in any minute now & tell you about Turbo, The economics of it & so on. In which case he would be absolutely right.

The only thing I ever regret taking out of my car was the fairly aggressive cams it had at 1 stage. I recon that's where I'll be eventually again. The right cams.....with poetry being recited over 5000 rpm.....but everyone likes different things.

[hks_kansei]

The only thing I ever regret taking out of my car was the fairly aggressive cams it had at 1 stage. I recon that's where I'll be eventually again. The right cams.....with poetry being recited over 5000 rpm.....but everyone likes different things.

That's the goal of where I want mine in a few years.
Big cams, tune it to work with them (biggest issue, damn ECUs are costly)

basically end up with something that's got good enough power, and looks pretty normal under the bonnet.

[StanTheMan]

My 272 cams ran on the standard ECU but the idle was like 1000 rpm....sounded almost like a rotary at the lights. peeps asked if it was quite regularly.

Once I took out the adaptronic it probably lost about 10 rwkw.....that's a guess of the backside so that would mean it would have been running somewhere around the mid 90's in rear wheel power. Realistically probably in the range of 90-95.

[Magpie]

This is the sound of a BP motor with a full racing beat exhaust system, ITB's, 288 deg in/ex cams and a solid gold airbox complete with tortoise shell/mother of pearl inlay (painted in wrinkle black to make it look cheap).
[/quote]

[pcmx5]

$$ for sound and performance I would leave the standard headers and do a high flow cat and 2 1/4 exhaust with a straight through muffler and hotdog in the midpipe and do a CAI.You can always chase the last little bit of power with headers later when you do the cams and ECU.

Hard to tell exactly what gain comes from this as it is a bit dependant on the condition of what you had on but ChrisH's 2001 went fron 74RWKW to 82RWKW with around 30000 klms and about 6 years old.It also had a reasonable increase in torque.Have seen other good gains on back to back dyno runs.

Good luck,

Peter.

[hks_kansei]

My 272 cams ran on the standard ECU but the idle was like 1000 rpm....sounded almost like a rotary at the lights. peeps asked if it was quite regularly.

Once I took out the adaptronic it probably lost about 10 rwkw.....that's a guess of the backside so that would mean it would have been running somewhere around the mid 90's in rear wheel power. Realistically probably in the range of 90-95.

yeah, the NAs are a lot easier in that regard, a mate had his old clubman running on the standard ECU with timing changed and biggish cams (plus headwork from memory) and I think made about 100rwkw

Unfortunately the NB is pretty stuck when it comes to all that, timing can't be changed, fuelling can only really be done by upping the pressure or fooling the AFM.

I have considered putting in one of the adjustable timing wheels and an AFM adjuster, but it's a lot of effort to get something that might not work well in the end.

[StanTheMan]

Yea I think PCmx5 is on the money. Originally I only did the CAI. That was sufficient for years. That was like wow!!! That's how it should sound stock. LOL
I assume the NB8A doesn't have ABS so the CAI should be possible. Right? the only NB8A which had ABS was the 10AE?

Just so the OP knows the deal. With the CAI we are talking about, you need to cut a hole in the firewall. Provided you don't have ABS. The ABS is lo9cated exactly where the CAI takes its air.
Other CAI which take cold air from the front don't have the same cabin theatrics like that one.
and since we had a NEWB allert. CAI stands for Cold Air Intake