Diesel exhaust systems

[Aaron113]

I often wonder if it's possible to upgrade the exhaust system to a better flowing one without making my car into one of those rolling coal type of mess on the road? (huge black cloud as soon as you push the gas pedal)

I'd be interested in some examples of diesel exhaust systems done right and where to find them/buy them (for regular cars not trucks in my case).

Any help on this matter would be greatly appreciated

 

[TCJBOLDIE]

Any turbo powered vehicle will benefit from a larger than stock diameter free flowing exhaust system as that will allow the turbo to be more efficient by reducing any back pressure after the turbine exit which then allows the turbo to spool up faster.

Been there done that

 

[Aaron113]

That's what i know basically exhaust upgrades, but since I'm talking about a diesel car, i really want to avoid a black cloud every time when i hit the gas pedal.

I was wondering if there are any products out there that could mitigate that effect while providing that exhaust free flow.

 

[Greg1990]

I’ve got a Volvo S40 2.0d..A friend of mine made a bespoke stainless steel exhaust for mine using 3.0” tubing and a single silencer...sounds very nice...no black smoke although it’s custom mapped for perfect fuel/air mixture..

 

[Aaron113]

Stock injectors?

 

[Greg1990]

Yes..stock injectors and stock fuel pump..it’s got a K&N performance panel air filter,hybrid turbo and a Nissan skyline GTR intercooler..

 

[Aaron113]

And with all those upgrades you have none of those black smoke issues or emission problems and such?

 

[Greg1990]

None at all....my engine is the same as the Peugeot 2.0 HDI 2004-2010...I may also add that I’ve also removed the DPF filter..

 

[Aaron113]

That's great then, i tried searching your posts about your volvo but didnt manage to find all of the details. Could you make a topic to sum up all your modifications and such if that isnt much of a hassle for you?

I plan to upgrade/change my exhaust system but my engine is 1.6 not 2.0 HDI so im not sure how things will go with that but what i am sure about is that it would involve removing the dpf and lots of other things + remap.

I just dont want to pollute like crazy and leave huge dust clouds behind me but on the other hand it feels very difficult to make modifications to a diesel car without the necessary know-how one should have.

 

[Greg1990]

Tap on “torquecars” on the top left of this page then tap on car forums..go to the bottom of the page where vehicle manufacturers are and tap on Volvo..my threads should be near the top..Removing the DPF & EGR will require a remap as engine management lights may/will come on?..A remap is a great first mod to do,you should see around 35-40% increase in power + improved MPG...Make sure you use a reputable mapper and you shouldn’t have any issues regarding lots of black smoke bellowing out behind you like something out of 007!,,lol...it’s generally the poor “generic” maps downloaded off the internet that causes all those problems usually down to over fuelling!...

 

[Aaron113]

There are so many things i don't know where even the simple dpf/egr/exhaust portion seems like too much info to soak in at first, the tiny details at least.

Regardless of that ill learn what i can and consult the best people for any future project i might have so there will most likely be a lot of random questions here lol

btw thank your for your time and input, i appreciate it, also your volvo looks awesome

 

[Greg1990]

No worries..there’s plenty of people on here who’ll be more than happy to help..and thanks for the comment on the car..she’s 12yrs old but well looked after..

 

[Aaron113]

Modifications know no age lol

Mine is 14 and im hoping for 150 ponies one day.

 

[Lunchmoney]

12 years, 14 years.... Mine is 20 this year

 

[Greg1990]

lol Lunchmoney but I wasn’t aware they did an STI diesel?..

 

[Greg1990]

Modifications know no age lol

Mine is 14 and im hoping for 150 ponies one day.

Mine is around 180BHP with around 400ftlb torque..with the new hybrid turbo and skyline GTR intercooler I’m hoping to hit around 230+ when she gets re-mapped?...and you should see 150BHP+ with just a good re-map?...

 

[Aaron113]

Well for starters im hoping for 125/130 with the removal of things like egr and dpf + replacing the exhaust system and then a remap followed by it, i got 110 now on stock and its a small car, you notice everything lol.

Then i would go for suspension upgrades, wheels maybe and tires. If all goes well ill inspect everything on the car and see what needs improving and then go for a slightly bigger turbo and injectors if i manage to not mess it up with the stage 1 portion.

Lots of ideas running through my head and at one point im asking myself why not swap a gti180 petrol engine in it and be done with it but maybe im hung up on the torque feel when the car lifts off. Where i live there's nothing but mountains and curvy roads so no point going past 200hp.

 

[Aaron113]

12 years, 14 years.... Mine is 20 this year

Lets make a party when it reaches 21yo lol

lol Lunchmoney but I wasn’t aware they did an STI diesel?..

There's an sti diesel?

 

[Greg1990]

Lets make a party when it reaches 21yo lol



There's an sti diesel?

No...lol..I’m just yanking his chain being a “scooby “ owner commenting on diesel chat...

 

[Greg1990]

Well for starters im hoping for 125/130 with the removal of things like egr and dpf + replacing the exhaust system and then a remap followed by it, i got 110 now on stock and its a small car, you notice everything lol.

Then i would go for suspension upgrades, wheels maybe and tires. If all goes well ill inspect everything on the car and see what needs improving and then go for a slightly bigger turbo and injectors if i manage to not mess it up with the stage 1 portion.

Lots of ideas running through my head and at one point im asking myself why not swap a gti180 petrol engine in it and be done with it but maybe im hung up on the torque feel when the car lifts off. Where i live there's nothing but mountains and curvy roads so no point going past 200hp.

If you do all the things you’ve mentioned in the first paragraph you will see well north of 150BHP...then look at upgrading the brakes..more go needs more slow..lol..

 

[Aaron113]

I sure do hope so but still take the safe road just in case. Usually the car comes with weak front disc brakes and drum brakes in the rear but on this one i got disc brakes front and back so i got that stopping part covered mostly + the car is lightweight.

 

[Greg1990]

You should be ok there then...mine was disc all round as standard but I still upgraded the fronts to 320ml gross drilled and groved with 4 pot callipers..it stops very well and I find I can outbreak most “challengers “..lol..you mentioned dropping a 180BHP petrol engine in?..Don’t!..I’ve had some seriously powerful petrol engined cars in the past but none of them have had the pulling power of my Volvo!..Power is all about top speed whereas “torque “ is all about acceleration!!..You’ll be surprised what power/torque you could get out of that 1.6 engine?..if you do all the mods I’ve done you’ll see north of 200BHP which is what you feel is your maximum?..

 

[Aaron113]

I really got hooked on the torque portion as you said, for me its all about acceleration and not top speed (since i cant really utilize it anywhere). That's the sole reason why i want to tune my car + it just looks so damn awesome too.

I'm just worried that from all that torque the crank might break or something but i think it can be solved with proper mapping or something. Im hoping for 150 anyway and if all goes well after a while ill start searching where i can buy forged internals for the engine (doubt i will succeed since i tried and failed so far).

 

[Greg1990]

Don’t worry about the internals...diesel engines will cope with quite an increase in power.They are built a lot stronger than petrol variants due to the higher torque that they develop even in standard form...It’s generally the injectors that may need uprating to supply the extra fuel.
Mine is still running stock injectors at 180BHP and I’m told I shouldn’t have to change them even with the new hybrid turbo and larger intercooler?...we shall find out in a couple of weeks when I get her on the dyno?...I’m anticipating that the clutch is going to be the weak link?...

 

[Aaron113]

Im curious to see how your results pan out, for some reason i recently got an offer for a 180 gti engine and a set of forged internals which is weird since i didnt really ask for any of that. I wanna see what the hdi has to offer first :Đ

 

[Greg1990]

Like I said before..with a decent simple re-map you’ll see 150BHP with better MPG and no effect on reliability..I’ve only done bolt on modifications...Other than changing the injectors or the clutch I wouldn’t start messing with internals such as crank/rods or pistons..I’m not trying to create a race car,just a good street car...The “wolf in sheep’s clothing “..

 

[Aaron113]

It's somewhat unfair how diesel engines are deemed not street worthy by just being a diesel. I'm looking forward to your "finalization" of modding the volvo (we all know modding doesnt stop until the car blows up lol).

 

[Greg1990]

We like our diesels here...they are so tuneable and still remain reliable not having a “spark” to worry about..I’m chomping at the bit having to wait to have her re-mapped!...Whatever power she does there is going to be a limiting factor stopping her doing more like injectors or clutch...that will be the next phase...lol..

 

[Aaron113]

Is it possible to make a large diameter exhaust system with a cat that has a larger (custom) honeycomb filter in case of an injector upgrade and black smoke issues?

 

[Greg1990]

Anything is possible but black smoke issues are generally down to over fuelling,this can happen when a poor quality map over fuels to make the power!..Those maps are usually “generic “ ones that have been downloaded off the internet and are not unique to that car..A custom dyno map is created that’s for the car in question which in turn minimises black smoke.I get a little puff of black smoke when I first accelerate hard but as the revs rise it disappears due to the fuel being burned more efficiently with the correct fuel/air mixture..That’s the beauty of having the map done on the rolling road,you can tailor the fuel/air mixture throughout the Rev range whilst the engine is under load,you can even play with the torque curve for it to develop the characteristics you may personally want?...I’ve waffled on a bit there..lol..Hope it makes sense..

 

[Aaron113]

I'm among those tough crowd kinda people, i like to measure things a few hundred times before cutting to make sure everything is up to the specs. When it comes to cars, i have never done any mods but at least i can learn as much as i can before applying it in real life. I can ask questions to no end lol

 

[TCJBOLDIE]

As a general rule diesel black smoke in a stock vehicle is the result of IMO blocked air filters and or injectors.

A free flowing big bore exhaust system should not increase or cause black smoke.

My previous 4x4 diesel dual cab ute had the muffler deleted and no smoke over the 170000 KLM's that I owned it.

 

[Aaron113]

So not even under somewhat heavy modifications should the smoke appear?

random example, this is what im trying to avoid at all cost

 

[Greg1990]

lol..all those cars have been modified and the owners have wanted them to black smoke and the way to do that is to have more fuel than air going in...It’s a craze over here with all the boy racers and the terms they use are..”where there’s smoke there’s poke” or “you don’t have poke without smoke “..both being untrue!...

I'm among those tough crowd kinda people, i like to measure things a few hundred times before cutting to make sure everything is up to the specs. When it comes to cars, i have never done any mods but at least i can learn as much as i can before applying it in real life. I can ask questions to no end lol

This is the place to ask all your questions...everyone will help where they can..

 

[Aaron113]

So basically, as long as i have the right amount of air/fuel mixture in the combustion process i should not see black smoke coming from the exhaust, even under modifications of any kind (as long as its the right kind)?

This is the place to ask all your questions...everyone will help where they can..

Thanks, i appreciate all the help i can get

 

[Greg1990]

I’m no expert but I originally had a “generic “ map installed off a laptop,it had the desired effect ie more power but under hard acceleration she smoked like we saw on the above video..When I had her mapped on the dyno the lad that did it said he couldn’t believe my car ran so well with the amount of fuel that was being dumped into it,he said it was so bad it should have destroyed the turbo!..He said he’d never seen an ECU so badly modified!...he then spent over 4 hours undoing what the back street mapper had done and then installed his custom map resulting in an extra 10BHP and 40ftlb of torque with you’ve guessed it...NO SMOKE!..he said all that smoke it was producing was just unburned fuel...just a query,what time is it in Canada?..it’s just coming up to 2:00pm here in England..

 

[Aaron113]

Yeah i figured the smoke being so black must be just unburnt fuel and generally a bad tune overall, i mean, why would you up the fuel injection if its not going to burn completely. Either im missing something the whole time or my guessing was right about it being just a bad idea.

I plan on going to a professional tuner that will do a complete dyno run(s), generic internet maps are out of the question. The rule of thumb for me is, if its so easy that even i can do it, it must be a bad idea lol. It's about 11:00am now

 

[Greg1990]

You only have to upgrade the injectors after you have done other mods like turbo and intercooler etc..you’re only around 5hrs behind us,thought it was more?...and like I said...my mapper spent over 4hr on my car and must have done around 30+ runs before he was happy with the engine map...

 

[Aaron113]

How much did the whole process cost you so far?

 

[Greg1990]

All in all I’ve spent around £1,500.that’s the map,DPF/EGR delete,hybrid turbo/custom made stainless exhaust and the new Nissan skyline GTR intercooler inclusive of all labour...The new map next week will only cost £100 per hour dyno time as he’s already mapped it before..not sure what that equates into Canadian dollars?...lol.
My tuning pal told me diesel track/drag cars with serious amounts of power will black smoke because they do run with very high fuel to air ratios..apparently it helps with keeping the engine cool under high loads at the cost of fuel consumption which isn’t really a concern in those applications...