[the_random_hero]

Ohai. About time I posted/became a member. I bought a '10 CRDI i30 with 37k kms on the clock a few weeks ago (I do a lot of driving for work and wanted something efficient). As much as I'm a fan of the car as it came from the factory, it's just way too quiet for my liking. I went to my old workshop (I worked in the automotive industry for quite a while) and did a 2.5" mandrel-bent catback (well, dpf-back) this morning with NO mufflers and I must say it sounds quite good - I have taken a video of it, however it's a bit big to upload to Youtube at this stage. When I work out changing the file format over I'll upload and share.
A tune is coming in the next few weeks, I know a few people are rocking interceptors but I went with tuning the factory ECU (as it beats everything aftermarket by FAR). Car is already very keen to spin the wheels, so I am planning on rocking some bigger feet (fitted 17x9 +17 Wedsports for the lols, waiting for a mate to upgrade so I can buy his 32GTR wheels within the next few weeks or so).

[eye30]

did a 2.5" mandrel-bent catback (well, dpf-back) this morning with NO mufflers and I must say it sounds quite good -

Can't wait for the vid but will this not get you in trouble with the law?


PS
Welcome to the club

[Phil №❶]

It would appear the factory warranty insn't big on your list of priorities. Define the word "rocking" please 

Welcome aboard. 

[Doggie 1]

Welcome to the forum.

[the_random_hero]

did a 2.5" mandrel-bent catback (well, dpf-back) this morning with NO mufflers and I must say it sounds quite good -

Can't wait for the vid but will this not get you in trouble with the law?


PS
Welcome to the club

It is -very- quiet, definitely legal. No issues with factory warranty as it touched nothing I can't easily reverse (I kept the factory exhaust including all gaskets).

As far as rocking, I mean people using interceptor ECU's (at least, a diesel-specific plug-in). Not keen on that - I want something that leaves no evidence it was installed if there is every any warranty issues.

[the_random_hero]

Looks good right? Tehe

[the_random_hero]

Sounds much louder than it actually is At idle it's the same as factory

[rustynutz]

Be interesting to hear it with the camera not right next to the exhaust......

Thanks for posting it anyhow...

[Dazzler]

Welcome Drew... I have mentioned before how I like red with Black wheels (are the other wheels you are getting similar?)

Will you get a spoiler? (I think they help the look of the i30 hatch a lot) They might be going cheaper now the current model is being superceded

We had a 2 inch Cat Back exhaust on our 2008 CRDi and it sounded a bit like a WRX under load 

Hope you Insurance company will be ok with the changes as they can't be easily swapped if you have an accident 

[the_random_hero]

2" is a bit too small for a 1.6L diesel. The factory exhaust is -very- good, one of the better ones I've seen on a factory, 'boring' car. The dump pipe isn't AMAZING and there are improvements to be had there, but as for cost vs. gain it's not really worth it. Went for a big drive today and I reckon the car is SLIGHTLY too loud to be perfect (only from 2000-2400rpm, maybe to do with the variable geom turbo?) - everywhere else in the rev range is spot on how I want it to sound.
Couple of extra little things I did - debadge at the rear, fitted seat covers/dash mat and 'boxed' in the intercooler/radiator with medium-density foam that's painted black. Not sure if there's any real gains to be had from that, but it's worked wonders on other cars in similar situations.

[rustynutz]

How about just fitting a hotdog muffler to quieten it a whisker? 

[komaterpillar]

Looks good right? Tehe

dish + stretch = *EPIC WINNINGS*

[Foglefar]

What performance gains do you think you got? I would be really interested in seeing a dyno ... Before and after.

What software and cables did you use to remap the ECU? Like you I prefer to remap rather than use piggyback modules (unless the modules have a proven track record).

These are mods I would like to do sometime in the future ... We manufacture mandrel stainless performance exhausts where I work. And mine doesn't have a dpf so tuning will be a lot easier.

I agree with a poster above that a resonator, say 4" round and about 14" long would take some of the harshness out of the peak revs and with no performance loss.

[Phil №❶]

@Fogelfar,

Interesting you work with exhausts, I know little about the dynamics of these. Can you explain how you obtain a good note without drone from any vehicles exhaust. Is there a formula for this 

[the_random_hero]

What performance gains do you think you got? I would be really interested in seeing a dyno ... Before and after.

What software and cables did you use to remap the ECU? Like you I prefer to remap rather than use piggyback modules (unless the modules have a proven track record).

These are mods I would like to do sometime in the future ... We manufacture mandrel stainless performance exhausts where I work. And mine doesn't have a dpf so tuning will be a lot easier.

I agree with a poster above that a resonator, say 4" round and about 14" long would take some of the harshness out of the peak revs and with no performance loss.

Doubt there would be really any performance gains - the factory exhaust is quite good as far as flow goes. There are some slight restrictions due to the venturis going into the mufflers, but I doubt it would be more than a hp or two. I actually ran it with the exhaust dropped off at the dump pipe for a little while - it wasn't at all droney so I decided to go with no mufflers. As you probably know that much straight pipe can introduce some resonance at certain rev ranges; it's not at all worrying and I don't even notice it after a few weeks of running it.
As far as drone goes, there's no real way to know what will happen apart from trial and error. Most 4 cylinders will require at least a long resonator and a large muffler - some, such as Lancers, will require TWO mufflers. Go with the physically largest, unfluted, straight-through muffler you can find, put it at the back then throw whatever will fit up the guts of the car - the quieter 4 cylinders are, the better note they have I did exhaust fabrication for quite a few years working at a fairly well known exhaust shop in Brisbane - we did everything from 300SL Mercs to Audi R8's to 700hp FD RX7's
I actually have a tech coming out from Bluefin UK to tune my car - I'll get some pics and do a bit of a writeup when this happens

[Foglefar]

Replying to 847563 ...

Drone is usually related to a turbo, although I have heard it with non-turbo cars with too large diameter exhaust and insufficient silencing. The trend with young blokes having a 4" exhaust on a 2 litre 4 cylinder is an example. Too large exhaust is also detrimental to performance. I wouldn't go larger than 2 1/2" on a small diesel like the i30.

But I would assume you are referring to turbo diesels. The drone is from the turbo and can only be reduced by silencing. That means a large as possible muffler ( straight through internals) or a second muffler if space dictates. Sometimes the drone is being transmitted through the firewall and not just out the exhaust so extra layers of insulation on either side can help. There is room on the i30 for extra insulation in the engine bay side of the firewall.

I haven't got the i30 up on the hoist yet to have a good look but it appears there is a small resonator and then a larger muffler. The note of an exhaust is influenced by a lot of factors including the engine, exhaust pipe size, muffler size, shape and construction and packing material, resonance chambers, resonator mufflers and sometimes outlet eg a megaphone.

Sorry, there are too many variables to have a neat formula. We usually develop exhaust notes by trial and error. I hope this helps.

Cheers, Richard.

[Foglefar]

Doubt there would be really any performance gains - the factory exhaust is quite good as far as flow goes. There are some slight restrictions due to the venturis going into the mufflers, but I doubt it would be more than a hp or two. I actually ran it with the exhaust dropped off at the dump pipe for a little while - it wasn't at all droney so I decided to go with no mufflers. As you probably know that much straight pipe can introduce some resonance at certain rev ranges; it's not at all worrying and I don't even notice it after a few weeks of running it.
As far as drone goes, there's no real way to know what will happen apart from trial and error. Most 4 cylinders will require at least a long resonator and a large muffler - some, such as Lancers, will require TWO mufflers. Go with the physically largest, unfluted, straight-through muffler you can find, put it at the back then throw whatever will fit up the guts of the car - the quieter 4 cylinders are, the better note they have I did exhaust fabrication for quite a few years working at a fairly well known exhaust shop in Brisbane - we did everything from 300SL Mercs to Audi R8's to 700hp FD RX7's
I actually have a tech coming out from Bluefin UK to tune my car - I'll get some pics and do a bit of a writeup when this happens

I agree. You posted this as i was replying to another post.

I work for Genie Performance Exhausts. We really only make 4wd systems and special custom builds these days cos that's where the market is. Who did you work for?

[the_random_hero]

Doubt there would be really any performance gains - the factory exhaust is quite good as far as flow goes. There are some slight restrictions due to the venturis going into the mufflers, but I doubt it would be more than a hp or two. I actually ran it with the exhaust dropped off at the dump pipe for a little while - it wasn't at all droney so I decided to go with no mufflers. As you probably know that much straight pipe can introduce some resonance at certain rev ranges; it's not at all worrying and I don't even notice it after a few weeks of running it.
As far as drone goes, there's no real way to know what will happen apart from trial and error. Most 4 cylinders will require at least a long resonator and a large muffler - some, such as Lancers, will require TWO mufflers. Go with the physically largest, unfluted, straight-through muffler you can find, put it at the back then throw whatever will fit up the guts of the car - the quieter 4 cylinders are, the better note they have I did exhaust fabrication for quite a few years working at a fairly well known exhaust shop in Brisbane - we did everything from 300SL Mercs to Audi R8's to 700hp FD RX7's
I actually have a tech coming out from Bluefin UK to tune my car - I'll get some pics and do a bit of a writeup when this happens

I agree. You posted this as i was replying to another post.

I work for Genie Performance Exhausts. We really only make 4wd systems and special custom builds these days cos that's where the market is. Who did you work for?

Exotic Exhaust @ Sumner Park.
In my experience it was NA cars that droned worse than FI vehicles, and generally those that were auto (especially Falcons/Commodores/Magnas). Turbo's actually act like a muffler themselves and definitely change the character of the exhaust note significantly - compare any turbo diesels with NA diesels to see what I mean.


Factory exhaust, looks around 60mm but haven't measured it (so just smaller than 2.5"). Notice the restrictions going into the front resonator. It is straight-through, while the rear muffler is baffled. Interestingly enough the rear section has been painted and it wasn't me.

[Foglefar]

I wonder if that restriction at the front ressie isn't deliberate ... Tuned length. There seems no other reason for it and I doubt it was poor construction/planning. The rear muffler would probably benefit from being a straight through I would think. It would be louder though. Have you looked inside? Possibly it is a reverse flow ... Looking at the pipe offsets.

[the_random_hero]

I wonder if that restriction at the front ressie isn't deliberate ... Tuned length. There seems no other reason for it and I doubt it was poor construction/planning. The rear muffler would probably benefit from being a straight through I would think. It would be louder though. Have you looked inside? Possibly it is a reverse flow ... Looking at the pipe offsets.

It's effectively a venturi to increase gas speed. You will find the majority of new cars on the market have them on their factory exhausts. There is no way to look inside without a flexi-cam - I can try to borrow one from work. I tried shoving some power cable through there but it hit a wall almost immediately - unsure what from.

[Lakes]

Just wondering if you use a flow bench to test the different exhast systems?

[the_random_hero]

Just wondering if you use a flow bench to test the different exhast systems?

Why? I already said I didn't care if it made any more power, it was just for a bit more noise.

[Lakes]

sorry i ment in general, not the i30 CRDi sytem. you said you worked in the industry, i was just wondering if they use flow benchs when they are designing performance systems?

[the_random_hero]

sorry i ment in general, not the i30 CRDi sytem. you said you worked in the industry, i was just wondering if they use flow benchs when they are designing performance systems?

Ah righto - that is not something I did. I found a lot of people would bring in x product that was advertised as flowing xx% more than another product, which lead them to thinking that it would perform xx% better than another product - completely wrong. What works in numbers definitely doesn't always correspond to what it will do in action. There are a few good practice guidelines you can follow, which the majority of shops will do, but a lot of 'performance' work is simply trial and error.

[bobbyd]

I didnt think the '10 model had a dpf?   Mine doesnt.  I'd be interested to know how restrictive the dump pipe is compared to the rest of the system, a bottleneck up front is going to restrict anything you do behind that.

[rackz]

just throwing something in to the mix. has any one got their car whistling like a big euro truck yet???  i work around truck all day and one sound i like is a new mack boosting up with a nice a whistle

[agentr31]

nah bra, they dont spool like a C16 with straight through 8'' stacks, there is a link in my thread what they sound like with no muffler, you might get it to sound a bit tougher if you remove the resonator, and cat converter...