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I'm splitting a thread into two separate discussions. This new thread is an excellent topic, but takes away from the original thread. This will also open it up to good input from vendors and other experts in the field of Exhaust and Intake Design.
The original thread was:
http://www.giuliaforums.com/forum/834-centerline-products/13354-centerline-corsa-exhaust-giulia-giulia-ti-magnaflow-16.html
which is specifically about a single item, the Centerline Corsa Exhuast by vender Joe Cab.

Thanks Triumph23 for approaching this subject. I find it fascinating, even if I don't have much to say.

Racer Z




For those who have installed the 3" Corsa pipe system, is there any difference in the low and mid rpm performance (Torque better or worse)?

Looking at it technically, my understanding is engines are mechanically tuned to some amount of backpressure and can show a loss of low-end torque when that backpressure is reduced too much i.e. too big a diameter of pipe. It is also perhaps true that the same engine that lost low-end torque with reduced back-pressure can be re-tuned to show an increase of low-end torque with the same reduction of back-pressure. I understand maximum "mid-to-high" RPM power will be achieved with the lowest possible backpressure but "low-to-mid" power (more importantly torque) would be better with some optimum back-pressure i.e. stock tuned exhaust pipe (2.5") or slightly bigger (2.75") ??

I think @[email protected] or @JoeCab mentioned the The MM ECU in the Giulia can adapt to any intake or exhaust mods you can throw at it. By this should I assume the ECU will automatically adjust the AF ratio to compensate for the reduction in back pressure which means the only biggest change going to 3" will be better tone of exhaust without any loss of low/mid torque? I am trying to understand the rationale for going to 3" diameter pipe and did it consider low end performance say between 1.5k and 3.5k rpm where the cars will spend most of their time while setting off and cruising.
 

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For those who have installed the 3" Corsa pipe system, is there any difference in the low and mid rpm performance (Torque better or worse)?

Looking at it technically, my understanding is engines are mechanically tuned to some amount of backpressure and can show a loss of low-end torque when that backpressure is reduced too much i.e. too big a diameter of pipe. It is also perhaps true that the same engine that lost low-end torque with reduced back-pressure can be re-tuned to show an increase of low-end torque with the same reduction of back-pressure. I understand maximum "mid-to-high" RPM power will be achieved with the lowest possible backpressure but "low-to-mid" power (more importantly torque) would be better with some optimum back-pressure i.e. stock tuned exhaust pipe (2.5") or slightly bigger (2.75") ??

I think @[email protected] or @JoeCab mentioned the The MM ECU in the Giulia can adapt to any intake or exhaust mods you can throw at it. By this should I assume the ECU will automatically adjust the AF ratio to compensate for the reduction in back pressure which means the only biggest change going to 3" will be better tone of exhaust without any loss of low/mid torque? I am trying to understand the rationale for going to 3" diameter pipe and did it consider low end performance say between 1.5k and 3.5k rpm where the cars will spend most of their time while setting off and cruising.

Car seems faster and quicker to me now post-Corsa. Of course it could just be because of the beautiful growl I now hear. But seriously I think it has a bit more punch to it.
 

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Now you need the V2>:)
 

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For those who have installed the 3" Corsa pipe system, is there any difference in the low and mid rpm performance (Torque better or worse)?

Looking at it technically, my understanding is engines are mechanically tuned to some amount of backpressure and can show a loss of low-end torque when that backpressure is reduced too much i.e. too big a diameter of pipe. It is also perhaps true that the same engine that lost low-end torque with reduced back-pressure can be re-tuned to show an increase of low-end torque with the same reduction of back-pressure. I understand maximum "mid-to-high" RPM power will be achieved with the lowest possible backpressure but "low-to-mid" power (more importantly torque) would be better with some optimum back-pressure i.e. stock tuned exhaust pipe (2.5") or slightly bigger (2.75") ??

I think @[email protected] or @JoeCab mentioned the The MM ECU in the Giulia can adapt to any intake or exhaust mods you can throw at it. By this should I assume the ECU will automatically adjust the AF ratio to compensate for the reduction in back pressure which means the only biggest change going to 3" will be better tone of exhaust without any loss of low/mid torque? I am trying to understand the rationale for going to 3" diameter pipe and did it consider low end performance say between 1.5k and 3.5k rpm where the cars will spend most of their time while setting off and cruising.
I think there is a slight sacrifice in low end torque between idle and say 1.8k rpms - emphasis on slight. With stock exhaust while in Dynamic mode at cruising speed on the highway, letting off throttle and back was very responsive while in high gear and in low engine rpm. With the Corsa exhaust, I feel there is a slight decrease in response while doing the same thing. But anything above 2k rpms there is a very noticeable improvement in engine response.

Can this slight decrease in low end torque be corrected? Absolutely! Either through a tune or better intake system.

For instance, I live in Miami and today we have our first cold front. Temperature around 63 degrees. The car was noticeably more responsive on low end rpms between idle (800-900) to 1.8k rpms then when the temperature is around 85 degrees. I was in dynamic mode. Better low end rpm engine response than in stock form. What does this mean to me? The car probably needs a tune to take advantage of the wider exhaust or simply a better intake and you can essentially eliminate the decrease in low engine rpm response.

Perhaps a 2.75 could provide better low end torque. But I enjoy the low growl and burble noises my 3 inch exhaust makes to even care. :grin2:
 

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I think there is a slight sacrifice in low end torque between idle and say 1.8k rpms - emphasis on slight. With stock exhaust while in Dynamic mode at cruising speed on the highway, letting off throttle and back was very responsive while in high gear and in low engine rpm. With the Corsa exhaust, I feel there is a slight decrease in response while doing the same thing. But anything above 2k rpms there is a very noticeable improvement in engine response.

Can this slight decrease in low end torque be corrected? Absolutely! Either through a tune or better intake system.

For instance, I live in Miami and today we have our first cold front. Temperature around 63 degrees. The car was noticeably more responsive on low end rpms between idle (800-900) to 1.8k rpms then when the temperature is around 85 degrees. I was in dynamic mode. Better low end rpm engine response than in stock form. What does this mean to me? The car probably needs a tune to take advantage of the wider exhaust or simply a better intake and you can essentially eliminate the decrease in low engine rpm response.

Perhaps a 2.75 could provide better low end torque. But I enjoy the low growl and burble noises my 3 inch exhaust makes to even care. :grin2:
throw in an intake and get some low end back!
 

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Looking at it technically, my understanding is engines are mechanically tuned to some amount of backpressure and can show a loss of low-end torque when that backpressure is reduced too much i.e. too big a diameter of pipe. It is also perhaps true that the same engine that lost low-end torque with reduced back-pressure can be re-tuned to show an increase of low-end torque with the same reduction of back-pressure. I understand maximum "mid-to-high" RPM power will be achieved with the lowest possible backpressure but "low-to-mid" power (more importantly torque) would be better with some optimum back-pressure i.e. stock tuned exhaust pipe (2.5") or slightly bigger (2.75") ??
This is a complicated topic. However I can attempt to address it somewhat. On a normally aspirated car what you actually need is proper exhaust gas scavenging, not back pressure. And yes it is possible to increase the exhaust diameter to the point where exhaust gas velocity falls off, interfering with scavenging, and this is where you will notice loss of low-end torque.

This same theory doesn't really apply to forced induction engines, they seem to work best with very little back pressure after the turbo.
 

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Discussion Starter · #7 ·
This is a complicated topic. However I can attempt to address it somewhat. On a normally aspirated car what you actually need is proper exhaust gas scavenging, not back pressure. And yes it is possible to increase the exhaust diameter to the point where exhaust gas velocity falls off, interfering with scavenging, and this is where you will notice loss of low-end torque.

This same theory doesn't really apply to forced induction engines, they seem to work best with very little back pressure after the turbo.
Ah now I see it! NA engines vs Turbo Engines! More obvious now... On a turbocharged system, back pressure is based on the flow characteristics of the exhaust manifold and the turbine/wastegate housings, which provide the most restriction on the exhaust side that whatever pipe is on the other end won't change or contribute to exhaust gas scavenging or gas velocity that much. So it matters less or insignificantly on a turbocharged setup. Smaller diameter than design will affect wastegate capacity causing turbo over-spool/boost creep etc. and obviously large diameter = different pitch of sound and perhaps that is the real limitation in choice of diameter. After the turbo, you want as free a flow as possible without regard to backpressure - the turbo doesn't need or want it. :wink2::nerd:
 

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Has anyone from Western Canada ordered the exhaust? I am looking for an estimate on shipping cost as that has the potential to dramatically increase the price of the exhaust relative to other options and mods.
Give us a call and we can give you an exact quote, all we would need is your address and post code.
 

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Discussion Starter · #9 · (Edited)
Ah now I see it! NA engines vs Turbo Engines! More obvious now... On a turbocharged system, back pressure is based on the flow characteristics of the exhaust manifold and the turbine/wastegate housings, which provide the most restriction on the exhaust side that whatever pipe is on the other end won't change or contribute to exhaust gas scavenging or gas velocity that much. So it matters less or insignificantly on a turbocharged setup. Smaller diameter than design will affect wastegate capacity causing turbo over-spool/boost creep etc. and obviously large diameter = different pitch of sound and perhaps that is the real limitation in choice of diameter. After the turbo, you want as free a flow as possible without regard to backpressure - the turbo doesn't need or want it. :wink2::nerd:
This is a complicated topic. However I can attempt to address it somewhat. On a normally aspirated car what you actually need is proper exhaust gas scavenging, not back pressure. And yes it is possible to increase the exhaust diameter to the point where exhaust gas velocity falls off, interfering with scavenging, and this is where you will notice loss of low-end torque.

This same theory doesn't really apply to forced induction engines, they seem to work best with very little back pressure after the turbo.
In the UK, given the limited custom/speciality make options, I just fitted a 2.75" cat back system - straight cat-back pipe and rear silenced resonator, to my car to try and see how it performed before deciding if going 3" would be better. While it sounds good, perhaps not as burbly as the 3" Corsa, I have noticed a slight reduction in throttle response between idling and 2k rpm with an associated reduction in bottom end torque. So, I am a bit puzzled now with @JoeCab 's statement that on the forced induction, turbo engine you need very little back pressure. If so why have I lost throttle response a little and torque at the bottom end? There certainly seems to be an effect on changing the exhaust :confused: By the way mine is the 200HP european variant. Is 2.5" factory size the ideal tuned diamter for the 200HP and will I need a ECU tune now to increase power/boost to get the benefit of exhaust?

EDIT: I am aware my question is not directly related to the thread topic but posting here for continuity based on question/answers previously posted.
 

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Discussion Starter · #10 · (Edited)
Been thinking about the noticeably slight loss of torque in the lower rpm range. One thing that has been stated is the need for correct scavenging in NA engines and less of a need, if any, for scavenging in Turbo engines and larger diameter pipe (cat-back anyway) is better for Turbo engines as the restriction is predominantly at the turbo itself and then the cat. But my finding after fitting a slightly larger diameter, freer flowing cat-back exhaust is a loss of low end throttle response/torque. I have carefully observed this over a few days and it certainly is not just my imagination. So this got me doing a bit more research and my conclusion based on current personal experience and some knowledge gathered is that exhaust pipe diameter does affect low end torque and performance in the rpm range ‘below’ where Turbo is ‘operating’ to create boost (forced induction). As below the Turbo operating range, the engine must still act like a NA engine, even if only partially.

In the low rpm band before the turbo is spooling at its most efficient operating region, exhaust gases are still emitted in pulses and the pulses will be further apart when the engine is just about ticking over or running slowly. The Turbo would dampen these pulses to an extent at this stage. Small pipes yield a high flow velocity. High flow velocity increases inertia of the flowing gas and smooths out the stop / start nature of gas pushed out by the engine. But the exhaust gas velocity is lower with the larger pipe diameter which could be affecting the scavenging from the turbo itself (it is not operating fully at this point and perhaps the wastegate is not fully closed yet?). The optimal exhaust size surely then is a function of exhaust volume and mass flow/velocity which will also to some extent affect the temperature of the gas in the exhaust manifold. On the Giulia, the exhaust collector is directly bolted to the Turbo housing. The greater the exhaust volume, the greater the optimal exhaust size. Exhaust volume increases with engine rpm and fuel delivery. Looking at the argument that on turbo engines larger diameter is better, I can’t help but think the turbo cannot perfectly and completely isolate the upstream pipe from the downstream surely? It’s just one pipe with an obstruction in it, no different to the effect of a catalytic converter or muffler?? So, what comes into the turbo must come out of it which means presence of a turbo cannot completely circumvent the gas flow physics that applies to NA engines especially when the engine is operating in the region where the Turbo is not fully operational. A larger exhaust downstream of the turbo will still hold more mass of gas which will be harder to accelerate (I find this sentence quite key as I do feel I am needing to give it a bit more throttle while setting off, accelerating from cruising ~2k rpm and find myself down shifting when in N or A modes to overtake. D revs higher so less of an impact). It will still yield less exhaust velocity and therefore less ability to continue to suck out exhaust between exhaust strokes. There MUST still be compromises involved otherwise the larger pipe would be there already?

Perhaps this is why I find going from 2.5” to 2.75” and with only 200HP (less boost), I have lost some of the responsiveness and torque until the turbo is fully spooled and running at its peak region. At this point perhaps having a freer flowing larger diameter pipe is useful. A quick scout around suggests the stock 2.5” is large enough for 300HP+ and 2.75” is obviously capable of a lot more. Perhaps then the only way to get the best compromise for low end torque i.e. retain what came from factory and ALSO improve sound is by having a freer smooth flowing pipe with less restrictions and sound deadening using ‘stock diameter pipe’. Alternatively, fuelling could be altered using ECU tune targeting just the 1k-2k rpm range to claim some torque back. Any thoughts?

NOTE: Again this post is not directly related to the Corsa exhaust but more to do with effect of larger diameter exhausts on performance. Only posting here for continuity!
 

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Every system has a balance. The engineers choose sizes and such, to balance out all the forces at work to get the best performance. Whenever you change something, you need to consider what else could be affected that might also need changing to keep that balance.

Intake and exhaust are part of that particular system. You've changed the exhaust; have you also changed the intake?
 

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I can't imagine noticing a "slight loss of torque" in a seat of the pants dyno. Post some dyno sheets before we start talking about power loss. I have the exhaust and V2 intake and have only noticed more power and a better throttle response. Triumph23, were you talking about your exhaust or the Corsa?
 

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Discussion Starter · #13 ·
I have not changed the intake. Did you notice better response and power with just the exhaust or was it after adding the V2 induction? Like I said mine is the European 200HP variant (which puts out 230HP in reality) which perhaps responds differently to the change in gas flow via the larger diameter pipe. Admittedly I have fitted a diameter larger than the 2.5" which is fitted to the 280HP variant of the same 2.0 engine also.

The Giulia is not easy to dyno and as I have tried it in the past unless you have access to the latest state of the art dynos which I haven't easily. I understand your stance but, the loss of torque and throttle response is perceptible enough. Perhaps using the word 'slight' is mis-leading. I drive the car everyday in all manner of roads over 50 miles. Having owned the car for nearly 9 months and 8000+ miles I have come to know it performance. Obviously in order to quantify the perceptible change it needs a dyno run, having said that most dynos are not very good at measuring from as low as 1000rpm as they are just starting to run and ramp up speed at that point. My question was more to do with the theory/confirmation bias that larger diameter pipes do not affect Turbo cars. I am not trying to prove any losses. I can feel a change in 'response' of the engine when I drive at low speeds and also when I overtake from cruising speeds in the low rpm band to the point that I have increased the setting on my throttle pedal booster to a higher setting to get a 'quicker' throttle action to drive the engine rpm to the higher band using the same degree of foot movement I am already accustomed to prior to the exhaust change.
 

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Sounds to me like hes talking about the remus catback with open center and resonated axel back. Triumph might not get the answers hes looking for as his car is the 200hp 2.0 and not the higher boost 280hp 2.0 that of us here have. I could believe he lost a little low-end on the system given a much less boosted version of the 2.0 as the designs of the remus and corsa were dedicated to the higher boost model. Alternatively you had some software updates or battery disconnected recently and system is "re-learning" again.
 

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Discussion Starter · #15 ·
Sounds to me like hes talking about the remus catback with open center and resonated axel back. Triumph might not get the answers hes looking for as his car is the 200hp 2.0 and not the higher boost 280hp 2.0 that of us here have. I could believe he lost a little low-end on the system given a much less boosted version of the 2.0 as the designs of the remus and corsa were dedicated to the higher boost model. Alternatively you had some software updates or battery disconnected recently and system is "re-learning" again.
I haven't had the battery disconnected and the ECU definitely is not re-learning as I did not notice any loss in response while driving to the exhaust shop. Remus indeed but here in UK there are no specific aftermarket systems for the 200HP and the system I have is marketed for the Veloce (your Ti / 280 HP). I did not name the exhaust as I don't believe the issue is to do with the brand name or the design which was developed on the 280HP. To that effect I believe the same thing would be seen with any of the exhausts on the 200HP. So perhaps the low end loss is likely to do with the less boosted version on mine. So in hindsight, I may have been better off installing a custom setup tuned for my power delivery, the 2.5" diameter being large enough for 300HP+.

In all reality I will be getting a ECU remap to get the 280hp map installed and then the exhaust should work as intended. My question here though is more to do with the effect on larger diameter pipe (vs) turbo engines. The impression I got is there should be NO change in low-end torque/response by going to a larger pipe on ANY turbo engine. And really I have only gone from 2.5" stock to 2.75" so even if the 280 version never existed it should only be a marginal increase in pipe size irrespective of boost available on the higher powered versions. That is the aspect that makes me ask the question as to if the mindset that Turbo engines don't need any back-pressure. Even the exhaust maker quote a 80% reduction in back pressure with the 1/4" increase in diameter. I think that is all wrong, its more to do with changing the exhaust gas velocity (lower) and exhaust gas mass (increase)with the larger pipes in the RPM band pre-turbo operation. All of this is just my supposition and I am happy to get some clarity from people who understand the dynamics better!0:)
 

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In the past when I've modified the exhaust to get 'better sound', and gone with big pipes, I've noticed a change in the low-end performance too. This is my first turbo car, so I don't have experience with turbos, but generally speaking you have to make changes to both intake and exhaust, if you significantly change the air-flow of either side of that. Intake side seems to be less critical, and usually makes an improvement of some kind when you're replacing factory filters and/or intakes, which is why I went with the Eurocompulsion V2 intake setup. It seems allowing more airflow in, doesn't have the same impact that moving more air out does.

I'm not a scientist or engineer, just a garage tinkerer so I'm sure someone who is (a real or internet engineer) will respond with a lengthy explanation of why I'm full of sawdust, but here goes.

As I understand the basics of what's taking place, it's all about getting air in, compressing it with air and fuel, igniting that, then removing that charge from the chamber so a new one can come in. The balance is to allow enough in, and removing enough for a clean recharge. The systems aren't perfect and have to work over a wide range of cycles. Most factory systems appear to be designed and tuned for the midrange of performance.

It seems that back pressure allows for a certain amount of charge to stay in the chamber; let's say just for the sake of discussion that it's 1/8 of a full charge. Let's also say that the intake system normally allows for 7/8 of a charge in, which is a combination of how much airflow the intake manifold is tuned for, in combination with the timing of when and how long the intake valves are open. All this is happening early on before you reach the midrange of the 'ideal' factory designed performance. The back pressure that keeps that 1/8 in, allows for a full charge for compression purposes when the intake refills it with 7/8.

If you change the exhaust so that it removes that exploded charge more effectively, because it allows an 8/8 removal at low rpm, the intake still only has enough time to refill it to 7/8 so that slightly changes the compression of that new refilled charge. Once you get up in rpm then you start to hit the designed timing, duration and performance range, so the new exhaust can actually make an improvement to a point, but at the low end it can actually cause a slight drop in performance.

If in addition to the exhaust, you also improve the airflow of the intake, that allows for a more efficient charge/evacuation process which means a new clean, full charge of fresh air and fuel is coming into the chamber. The power increase is due to more new fuel/air, versus the old system with its back pressure that kept 1/8 of the old already-detonated charge in there. (These numbers are purely for discussion's sake)

A turbo will stuff every bit of air pressure in that it can, regardless, so once it kicks in that dynamic takes over compared to naturally aspirated systems. Improving the airflow in and out will most likely show the most benefit before the turbo kicks in, and once you get past the midrange; it will extend the usable power range up near the top within the mechanical limits of the system.

The short version? You probably need to improve the intake side too. I highly recommend Eurocompulsion's V2 system. Top quality, and works as advertised.

So there you have it. Eagle7's cheap, basic 2-cent diagnostic of your situation. In the words of a famous well-known engineer: "It needs more cowbell".
 

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It is very feasible that you are feeling a loss of lower rpm range torque. To be honest, without measuring closely on a dyno with controlled variables, this is the place when driving where it would be the most noticeable and easiest to pick out.

Occasionally, going to a larger diameter pipe further back in the system will result in loss of lower end torque and pick up. This is typically a trade off for higher rpm power. The larger diameter piping decreases exhaust velocity (how fast exhaust gases are exiting through the pipe), which creates turbulence in some cases (basically inefficient gas flow, or "tumbling" as I've seen it referred to). Turbulence can hinder performance, especially down low where there is not enough exhaust gas velocity created to keep flow steady in larger diameter piping.

Another effect this may have is on exhaust pulsing, or scavenging. Gases pulse upon exiting the engine on the exhaust stroke, and the space between the pulses creates a vacuum that helps pull the following pulses along. When the speed of the pulses is greater, the more effective scavenging will be, and this increases how efficiently the gases will be pulled through the exhaust.

The best balance for sizing and location of the exhaust change is to reduce restriction without losing too much velocity, which will eliminate turbulence.

With a larger and more complete exhaust replacement, it will be better accompanied by more performance modifications and tuning (perhaps the 280hp remap) to maximize the change in high rpm power, and possibly curb the loss in the lower range. As Eagle7 said:



There are always trade offs and compromises, it really just depends on what your goals are.

EDIT* I forgot this was Joe's thread, otherwise I may not have posted all that rambling. But I will say the Centerline Exhaust is balanced in the way I mentioned, eliminating restriction with larger diameter, but the location of the size change allows for all other factors to perform efficiently.
 

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OK, I have a couple of questions some more well thought out than others:

1) Motorized equipment operated in certain areas are required to have a spark arrestor. Failure to have such equipment can result in civil penalties in the Billions of dollars range (worst case). I spend a lot of time driving in such areas and own a house in such an area. Does this exhaust system meet requirements for spark arresting? I believe that the muffler on most cars is expected to to the spark arresting.

"Spark" is a misnomer in this context, "flying red hot debris trap" is more accurate than spark arrestor, but of course it is hard to say. The debris is typically carbon build up (sometimes also little fragments of rusty steel) from anywhere in the system. Look it up, a non-trivial percentage of all wildfires are attributed to engines that lack a spark arrestor.

2) At low RPM, is it possible to tune the length of the exhaust pipe so that the pipe resonates and "sucks" the exhaust out?

3) If turbulence is an issue with large diameter pipes, is it possible to roughen the interior surface of the pipe to minimize the drag? This would be similar to the golf ball dimples phenomena.
 

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The larger diameter piping decreases exhaust velocity (how fast exhaust gases are exiting through the pipe), which creates turbulence in some cases (basically inefficient gas flow, or "tumbling" as I've seen it referred to). Turbulence can hinder performance, especially down low where there is not enough exhaust gas velocity created to keep flow steady in larger diameter piping.

Another effect this may have is on exhaust pulsing, or scavenging. Gases pulse upon exiting the engine on the exhaust stroke, and the space between the pulses creates a vacuum that helps pull the following pulses along. When the speed of the pulses is greater, the more effective scavenging will be, and this increases how efficiently the gases will be pulled through the exhaust.

The best balance for sizing and location of the exhaust change is to reduce restriction without losing too much velocity, which will eliminate turbulence.

With a larger and more complete exhaust replacement, it will be better accompanied by more performance modifications and tuning (perhaps the 280hp remap) to maximize the change in high rpm power, and possibly curb the loss in the lower range. As Eagle7 said:

EDIT* I forgot this was Joe's thread, otherwise I may not have posted all that rambling. But I will say the Centerline Exhaust is balanced in the way I mentioned, eliminating restriction with larger diameter, but the location of the size change allows for all other factors to perform efficiently.


Not rambling at all. Like I said any real-world input from guys like you who make these mods all the time is invaluable. I am only trying to understand the dynamics of changing diameter which then will hopefully help me match the mods to what my needs are. 'Tumbling' is a very good word. It kind of describes what I feel on throttle application and let off. It feels like the engine is working slightly harder to push the increased mass of exhaust gas in the larger pipe and also on repeated throttle On/let off trial I can feel some uneven response almost like the gas is 'tumbling' based on the exhaust note I hear. So what you are saying makes perfect sense. There will be some who may say all of this cannot be 'felt' and need to be quantified using measurement but our brain and senses are perfectly capable of getting a "feel for things" and compare against what was felt before thus "qualify" the experience rather than quantify which can sometimes be binary. I certainly do not want to lose the low end torque so will be looking at the 280HP+ map soon after the first service which is only another 800miles away. I will also look to install a performance high flow filter and then get the ECU tune which are being offered by some reputed Alfa Specialists here. After all, the exhaust was developed for the 280HP map. In the meantime, I may try putting the factory front 'resonator' section back on and see what effect this has with just the axle-back system with the transition from 2.5" front to 2.75" rear muffler pipe.

Thanks for all the input and I only wish you guys had a branch over here so I can just drive up to you get everything sorted.:wink2::smile2:
 

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I didn't realize you had the 200 HP engine. I'm sure there might be a difference. I noticed more power with the exhaust alone. When I added the V2 I eliminated almost all of the throttle lag and really got a boost in performance. I will correct myself in saying that a "seat of the pants" dyno can detect changes and yes, you should of purchased an exhaust tuned for your engine. If you followed the Eurocompulsion thread you would see how much they put into testing the exhaust and V2 intake before making it available.
 
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