Dinan exhaust

[jmflukeiii]

Sorry to bump an old thread, but I was just about to pull the trigger on a full Dinan exhaust set, but after reading all this about only two of the pipes actually functioning, I don't want that. Sure maybe it's purely for aesthetic reasons, but really?

Is this truly how it is or have they created a new exhaust?

[AMPowerJ]

Originally Posted by jmflukeiii

Sorry to bump an old thread, but I was just about to pull the trigger on a full Dinan exhaust set, but after reading all this about only two of the pipes actually functioning, I don't want that. Sure maybe it's purely for aesthetic reasons, but really?

Is this truly how it is or have they created a new exhaust?

That's how it is and I agree it is bothersome. I might overcome it anyway one day because I think it is one of if not the best full exhaust system for the M3 balancing power, sound, lack of drone(volume), and looks.

[///M Ryder]

If no one told you, you would never know it has 2 dead pipes....the sound is pure and the piece of mind you get with Dinan is priceless. C'mon jmflukeiii, get off the fence man. Slap the exhaust on and go turn some heads ..............Phil

[jmflukeiii]

Originally Posted by ///M Ryder

If no one told you, you would never know it has 2 dead pipes....the sound is pure and the piece of mind you get with Dinan is priceless. C'mon jmflukeiii, get off the fence man. Slap the exhaust on and go turn some heads ..............Phil

Hah! Thanks... that's why I wanted the Dinan in the first place. I've done it before and been perfectly happy, plus now I live in Florida (no cold weather, completely undetectable that only two pipes would be working). I love the look of it, love the "like original BMW" quality, I haven't heard a fully system sound but like the exhaust note, gotta pull the trigger. Thanks for the push

[gsalequeen]

I have installed the full Dinan exhaust with the software on several E9x M3's. I explained this one tip exit only to all of them. Not one person say no. But I do understand peoples concerns. Personally it doesn't bother me at all. I care for the power and the sound and the fact there is no drone while at highway speeds. But to each his or her own. Good luck in your decisions.

[Draff1]

I too am wrestling with the dead pipe issue but more importantly, the small diameter and flat black single wall tips look pedestrian IMO. I could even live with all that but $5200 before tax and installation for 25HP seems extreme.

[jmflukeiii]

Originally Posted by Draff1

I too am wrestling with the dead pipe issue but more importantly, the small diameter and flat black single wall tips look pedestrian IMO. I could even live with all that but $5200 before tax and installation for 25HP seems extreme.

I'm very excited about my AA signature exhaust rear. I love the sound and have heard its not overly obtrusive as the Gintani or Meisterschaft.

Having thought it over, I'm going to hold off on an x pipe for now and just see how the car sounds with the rear alone. AA on the phone tried to convince me that the racing catless x-pipe wouldn't be too loud, but that's not what I hear from everyone around here nor the guys who are going to install the rear exhaust.

[dcstep]

Originally Posted by jmflukeiii

I'm very excited about my AA signature exhaust rear. I love the sound and have heard its not overly obtrusive as the Gintani or Meisterschaft.

Good choice. That's what I did. At autocrosses people are constantly asking which exhaust I have and saying it's the best sounding M3 or BMW that they've heard. IMHO, changing the X-pipes and removing the cats results in too much sound for "adult" daily driving.

Dave

[jmflukeiii]

Originally Posted by dcstep

Good choice. That's what I did. At autocrosses people are constantly asking which exhaust I have and saying it's the best sounding M3 or BMW that they've heard. IMHO, changing the X-pipes and removing the cats results in too much sound for "adult" daily driving.

Dave

Yes, this is my worry. I'm young, but I run a business in which I'm exposed consistently to ultra-high net worth people. I can't be driving around in something that sounds like a, pardon my expression for lack of a better term, rice rocket. That being said, I do want some sound as this is a V8 sports car, it should be louder and sound like one. The rear section should be here next week and I'll make the judgement then. My shop owner is going to take me out in a couple M3s he has around that have cat-less mid pipes so I can get a feel as well for what that would sound like.

[dcstep]

Originally Posted by jmflukeiii

... My shop owner is going to take me out in a couple M3s he has around that have cat-less mid pipes so I can get a feel as well for what that would sound like.

Why go catless? If it's only about sound, there's no doubt that it'll be considerably louder than just the AA rear section.

If you need a performance gain, then go with quality high-flow cats and change the final-drive. Catless you risk trouble with "the man" and you hp gains won't be worth the hassle.

Anyway, listen for yourself, but I think that the AA by itself is a better bet for one wishing to appear "professional."

Dave

[jmflukeiii]

Originally Posted by dcstep

Why go catless? If it's only about sound, there's no doubt that it'll be considerably louder than just the AA rear section.

If you need a performance gain, then go with quality high-flow cats and change the final-drive. Catless you risk trouble with "the man" and you hp gains won't be worth the hassle.

Anyway, listen for yourself, but I think that the AA by itself is a better bet for one wishing to appear "professional."

Dave

I appreciate the advise, we'll see and I'll obviously post it. As for the man, no problems with that in Florida.

[kitw]

The only thing that bugs me about the Dinan fake tips is that when you are behind a dinan car coming up to a light, the dead tip is very obvious with HIDs shining into it.

If I ever got one, I would paint the inside of the tip including the muffler surface to reduce this.

[JCtx]

Originally Posted by Draff1

the small diameter and flat black single wall tips look pedestrian IMO.

Same here, but they're NOT tips man. Tips is something you either weld or attach to the muffler tubing. Dinan just coats the muffler tubing, so doesn't even have tips. Plus the fake one is not acceptable on this car IMO. They should have made a 'Y' tip, rather than an obvious fake. Not ideal either, but better. Not worth what it costs, but I like how it sounds.

[Omerta]

After awhile the DINAN logo on the fake one is as good as new but the logo on the one in use gets faded. It takes some time for this to happen but it is very noticeable. I asked... it would be easy for them to make both tubes work so why??.. easy answer was that it is set up to give the amount of back pressure they wanted with there system.

[Reedomn]

Very Happy with the Dinan!!..the sound is perfect for DD...........

[Hunter399]

The fake tip does bother me. But the sound really makes up for it. I have the full system and really enjoy it.

[stega]

If you guys would read the paper on Dinan's site about their e92 m3 exhaust you would understand why they decided to use one tip on each side...

Pics would not copy over but here is the text:
http://www.dinancars.com/university/#block5

DINAN'S E90-92 M3 EXHAUST
By Steve Dinan

After many months of development and far too many dyno-runs to count, our Free Flow Exhaust for the M3 is now shipping. I couldn’t be happier with the finished product as our team of engineers were able to accomplish every goal I had established for the performance muffler: improved flow for increased power, reduction of weight, a “throaty” exhaust note and a purposeful high performance look. As our M3 exhaust employs a very unique design approach in order to accomplish our objectives, I thought that a more technical discussion on the subject might be of interest to performance enthusiasts. This paper will discuss a bit of general exhaust theory, the specific approach we have employed for the E90-92 M3 exhaust, as well as attempt to dispel some common misconceptions about exhaust tuning.
Exhaust Theory

There are three major areas of the complete exhaust system that are typically tuned for enhanced performance; the exhaust manifold with catalyst or header, the middle exhaust section with catalyst and the rear muffler(s). The exhaust manifold’s length, tubing diameter and the manner in which each cylinder is linked to the other is critical when attempting to maximize an engine’s power output. The manifold configuration can be manipulated in order to generate maximum power throughout the entire RPM range, changing the shape of the power curve accordingly. Naturally some compromise must be accepted when tuning an exhaust manifold for a street-car as the goal is typically to ensure balanced power output at low, middle and high rpm. This is in contrast to a race-engine where the exhaust manifold can be tuned specifically for maximum performance at high rpm.

After the exhaust manifold or header, optimum performance comes from making the balance of the exhaust system as short and large as possible. This approach will result in greater engine efficiency for maximum power, as well as minimizing the weight of the system. Probably the best example of an optimized, nocompromise exhaust system would be that of an F1 racecar. If you have ever had the opportunity to hear a F1 exhaust note, I think you will agree that it is best described as deafening. Clearly an exhaust system that even approached such a volume level in a performance street-car would draw far too much of the wrong sort of attention. Therefore, a modern street-car exhaust represents a number of performance compromises in order to achieve an acceptable exhaust volume, as well as meeting emissions standards. In order to accommodate the various components and baffling necessary for a street-car, the exhaust system becomes longer and the flow of gasses more circuitous as noise and emissions standards are addressed. Each bend in the exhaust tubing, catalytic converter, resonator and so forth introduces restrictions to the exhaust flow, particularly at higher rpm where flow is most critical. Exhaust flow can actually reach hundreds of miles per hour when the engine is producing maximum power, which results in power robbing friction along the exhaust tubing walls, particularly when the gasses must change direction. This friction results in increased backpressure that can be quantified with a pressure gauge. This backpressure restricts the amount of gasses that can be passed through the engine, resulting in a reduction of peak power. I’m fairly certain that many of you have been exposed to a “bench racing legend” that would have you believe that increased backpressure will improve low rpm power and that low backpressure will increase high rpm output. Nothing could be further from the truth. An exhaust system is sized for maximum flow at wide-open-throttle and peak rpm. All exhaust systems are “oversized” for lower engine speeds (rpm), as backpressure is so insignificant that it can’t even be measured. Less backpressure always results in more power at higher rpm, with no negative effect on lower engine speed performance. The amount of power that can be extracted from an engine at a given rpm as a result of exhaust design is really limited by the exhaust manifold or header. After the header, less backpressure is always better. The real challenge when tuning a street-car exhaust is to increase flow without making the system loud or eliminating catalyst that will prevent you from registering your car because of your local emissions standards. It is also important to understand that vehicle manufacturers must meet more stringent maximum noise requirements than aftermarket manufacturers.

Headers have become very popular in recent years because they make substantial power gains. The real reason they gain power has more to do with eliminating the front catalyst that is built into the header than the header itself. Modern M Cars have very high quality well tuned headers but to meet the emissions standards, there are four catalysts, two in the header and two more in the center exhaust section. The two three-way catalysts on the header are monitored by secondary O2 sensors to report catalyst efficiency to the ECU. There are two more catalysts mounted under the floor before the resonator and are not monitored by the O2 sensors for catalyst efficiency. The front catalyst mounted on the header are usually twice as restrictive as the rear catalyst and are as close to the engine as necessary to light off cold to improve exhaust emissions on cold start.

Dinan has decided not to make headers for the new M Cars. The reason is removing the front catalyst poses some severe problems aside from the obvious one which is, it is illegal. While many companies have headers to remove the front catalyst and software to prevent the car from setting a fault, these software changes also prevent the ECU from setting catalyst readiness monitors. Readiness monitor is software that checks that circuits are complete and conditions are correct (ready) to monitor a system and determine if there is a malfunction. Most states require a readiness check to pass a smog test even if they don’t have a tailpipe test to measure the emissions output like California does. Since you cannot pass the readiness test once you have removed the front catalyst it is impossible to get a smog test on a new car once they have been removed. In California the car won’t pass the tailpipe test as well. It is a day or two of labor to remove the catalyst and put the stock ones on and then another day or two to put your headers on every time you need a smog inspection if you choose to circumvent the law. A lot of hassle and cost for about 20hp. This is why we don’t offer headers on new M cars. In addition we just don’t want to make a car that dirty pollution wise since we need to live on the planet. We also don’t want our customers to be put in that situation when they need a smog test for their car. On racing applications like our prototype cars we make custom headers tuned for the racing engine with no catalyst.

Dinan will be making a middle racing exhaust system for the M3 similar to the one we manufacture for the M5 and M6. This racing exhaust will remove the second stage or rear catalyst. Removing the rear catalysts with a high performance middle exhaust section while still illegal is a lot more practical. First off the middle exhaust system cost about ½ to 1/3 the cost of a header. The labor is also much less to install the middle exhaust section. The car will still pass a smog test at the tailpipe and there are no faults set or readiness issues to deal with when you get a smog test either. This is an Ideal system for a showroom stock race car T-1 T-2 where the car must pass a smog test at the end of a race and cannot have a check engine light on. The gain about half of the front cat or 10 hp but there is no hassle and it is a lot less money. On Dinan’s middle exhaust system we also include 3 different noise level resonators so you can get the sound you are looking for from your car.

Moving on to the rear exhaust or mufflers, BMW’s current M-cars feature a distinctive quad exhaust tip design, punctuating the car’s high performance image. This approach is very logical when applied to a “V” engine configuration because there are natural dual exhaust outputs with this engine design, as indicated in the following diagram.
M5 EXHAUST
M5 EXHAUST
Rear Exhaust Design Approach

When it comes to the E90-92 M3 muffler, however, the vehicle design did not lend itself to the more traditional twin muffler approach, necessitating a cross-over within the single muffler case in order to feed the four tips and reduce noise to an acceptable level. This design requires that the exhaust flow has two 90 degree bends in each side plus a “Y” pipe on each side to go from one input pipe to two tailpipes per side. These turns and “Y” pipes as indicated in the following diagram, increase back pressure.
E90/E92 M3 Stock Rear Muffler

Months of testing demonstrated conclusively, that requiring exhaust gasses to make four 90 degree turns within the stock muffler’s internal chamber results in a increase in back-pressure. The stock exhaust also incorporates a Helmholtz chamber within the muffler to tune low frequency drone out of the exhaust. During development it became obvious that the Helmholtz chamber would be necessary to maintain reasonable noise levels. In addition the “Y” pipe at the tail-pipe amplified the low frequency drone when compared to a single straight pipe.

Because of power robbing turns and weight it was decided the mufflers needed to be straight trough with no bends or turns within the muffler case. Also because of low frequency drone it would also be necessary to incorporate a Helmholtz chamber within the exhaust. With this combination we had power, light weight, reduced noise and low cost. All the things you are looking for in a high performance exhaust. However once we incorporated a “Y” pipe at the tail pipe like the original BMW design to make quad exhaust tips the low frequency drone came back. It was possible to make the drone go away with the 4 - 90 degree turns like BMW used but we lost significant power with a large increase in weight and cost. Or it was possible to get good flow and a low frequency drone with 4 tailpipe tips, but it was impossible to get both. We considered using an external Helmholtz chamber like some companies have done. But this added additional weight and cost and was deemed unacceptable. Analyzing other after-market manufacturer’s mufflers revealed that they had all made a compromise because of these problems. Either they had high backpressure from keeping the BMW design or very loud low frequency drone with straight through twin muffler designs or heavy expensive exhausts with straight through designs and external Helmholtz chambers. Despite mounting pressure from M3 owners to deliver the Dinan exhaust, we made a conscious decision to continue working toward a design that accomplished our stated objectives. While we certainly would have preferred to begin shipping the systems sooner, I simply won’t accept compromises when it comes to performance.

We worked and worked at designs that would maintain the dual exhaust outlets but each iteration resulted in a heavy, low frequency drone with far too much back-pressure to produce any substantial power gains. After analyzing many designs, we came to the conclusion that a more radical approach was required in order to produce a truly high performance exhaust. Further pressure tests and dyno runs confirmed our suspicions about the best approach for the M3 muffler. Adopting a completely new design approach resulted in a significant improvement in flow. The exhaust note became throaty and aggressive, without being loud. Weight was reduced from 56 to 41 lbs. As you can see from the diagram below, our M3 exhaust utilizes the one active outlet per side. Recognizing that the four tips have become a significant visual design element for modern M-cars, as well as the fact that the rear valance has a cut out to accommodate four tips, both sides have a second tip that is inactive. While they are non-functional, the M-car look is retained without compromising performance. The 3" tips have been ceramic coated black for a striking high performance look, while eliminating any concern over uneven discoloration that would occur with polished stainless.
E90/E92 M3 Dinan Mufflers

The system produces measurable power gains, looks great, is light weight, low cost and produces the exhaust note M3 owners have been waiting for. I believe that this latest exhaust design underscores the importance of real engineering and extensive testing. The end result is BMW-like fit and finish combined with the best warranty in the business makes for the definitive solution for your high performance M3 exhaust.

[jmflukeiii]

So after doing some further research, hearing cars in person, talking to shops, etc. I'm definitely going with Dinan. The Dinan exhaust with mid-pipe and ECU is what I'll be starting with, but had always planned on going forward with Dinan throttle bodies and differential. So why not do it right and go all Dinan. I want to give special thanks to C2 Design in Tampa for all their help. I highly recommend this shop to anyone that would like special care taken of their car.

Anyway, what changed my mind is that my shop owner took me out in his Dinan M3 (6MT) and then also his friend's Dinan M3 (DCT). Both of these cars sound absolutely ferocious. The idle rumble is perfect on them and the car throughout the powerband makes a much deeper and fuller note. And it pulls hard too; much harder than my stock set-up. Dinan did it right; that car has much more mid range torque (the DCT was only exhaust and tune and was definitely way more powerful in the mid range and top end, the 6MT had the differential - that car pulled insanely hard throughout the powerband, really bringing the car to life in the sub 4-5K - the diff is definitely the way to go. They claim 14% increase in torque throughout the powerband on the DCT 3.62 Diff and you can feel it).

Well those are my thoughts. The system is not to quiet, not at all. The Dinan pipes look incredibly aggressive; I came to the realization, like that last post, if Dinan made it that way (with two functioning pipes), they did so for a reason. On all cars, there are unfunctioning parts that are added for aggressive looks. This is one of them, but it happens to also give you performance, noticeable performance.

[L-Altos]

Even with HIDs you wouldnt notice it unless you got out of the car and were at eye-level with the tips. The only time you will ever see it is on a cold morning, and there is no movement in the atmosphere.

When I got my M3, it already had the Dinan on. I didn't know it had fake tips for almost two months.

Originally Posted by kitw

The only thing that bugs me about the Dinan fake tips is that when you are behind a dinan car coming up to a light, the dead tip is very obvious with HIDs shining into it.

If I ever got one, I would paint the inside of the tip including the muffler surface to reduce this.

[jmflukeiii]

Originally Posted by L-Altos

Even with HIDs you wouldnt notice it unless you got out of the car and were at eye-level with the tips. The only time you will ever see it is on a cold morning, and there is no movement in the atmosphere.

When I got my M3, it already had the Dinan on. I didn't know it had fake tips for almost two months.

Yeah Its not even an issue with me anymore, especially since I live in Florida. Its never cold..... But beyond that, the pipes look awesome and after reading Dinan's explanation, it makes sense. I know they can write things to promote their product, but I believe what is written. And I believe the gains they say they can achieve. And I feel just all the more comfortable with Dinan parts on my car.