Ryan,
Just caught your post and your questions. We have tons and tons of info and datalogs. Our write up described this pretty accurately. Below is what we wrote in our "Wheres the R56 Supercharger Pulley Go".

We found that the car built boost much faster, and while waiting for the run to begin we hit 3psi more.

Also how back to back is your runs?


TURBO BACK TIME!

Next up was the turbo back exhaust. The turbo back exhaust consists of the same basic parts as in the cat back, add a 3” mid section with CARB legal cat, and a downpipe with another CARB legal cat. The complete turbo back system is 3” everywhere, but the first 8” are 2.5” tubing to make the turbo connection and gain clearance around the header. One of the most important features is that the OEM heat shields fit over the downpipe. This we feel is very important as the turbo sits so close to the hood.

Onto the dyno test. Like the catback by itself adding the downpipe and midpipe netted very good gains. We gained more than 20WHP and 20ft-lbs which is awesome considering the car still runs the same boost levels during these runs. Besides the HP we gained during the runs, one thing we noticed was while the car was in its holding pattern on the dyno, it was getting 7psi of boost now, not the 4-5. This is also seen on the graphs by the huge 40ft-lbs gained at 2000 rpm! So another important thing to take note of! This would definitely be noticeable on the road at low rpm. Sure enough, on the freeway cruising around, we get nearly instant boost response.

We are setting the standard from which others will be judged from. Yes another company has an R56 exhaust out, but its 2.5” and they never did a before HP run. So they claim it makes 27HP because they made 202 at the engine, and since the stock car is supposed to make 175, it must make 27HP. Not very good proof IMHO.


Above graph shows averaged runs with the 3" ALTA Turboback installed.

 

Also i forgot to add our system has (2) high flow metallic cats, and 2 mufflers. Not that the mufflers are restrictive, as they are 3"ID mufflers. where you have 1 cat and one muffler. We tried to make our system a legal replacment system (since the car comes with 2 cats).

 

Hi Jeff. Yes I've read your write up, I also have tons of datalogged info. My dyno pulls were conducted when the IAT and ECT's were identical. With the enormous drum and blower fans used at my local chassis dyno shop, it takes only a few minutes to level the values for each pull. I understand you're trying to market your exhaust, that's fine. I have no intention of replicating or marketing my piece, it's strictly for my fabrication and testing entertainment. Why our results are so different I'm not sure, especially in the boost controller department. Also I noticed you were pre-loading your car on a DynaPack...I used a DynoJet, which doesn't have any of that artifical pre-loading, so our dyno results aren't exactly comparible unfortunately.

 

Oh no, i wasn't trying to get in your thread and market ours, i had just noticed your question to us about if we have data from our dynoing. Some of that data was in that post, so i posted it. So no worries, and no reason to explain your not going to market your system. I think it is pretty cool you have the ability to make a one of for you own car. I just wish we would have had it done sooner so you could buy ours

But regarding the results.
Your right that is why the results are different. The nice thing about the dynapack is that you set a settle RPM, and a time it stays there. That makes is very repeatable run to run and car to car. Basically you say, i want the run to start at 1300RPM, and a settle time of 3 seconds. You floor it, and it goes to 1300 and stays there for 3 seconds, then it lets the run go. The dynojet is controlled by your foot and the weight of the rollers(or load cell if equiped), so you may not floor it at a low enough RPM to build boost when can.

I bet on the road your car spools better and you get more boost at 2000 RPM. At least that is my guess.

But after say 3000-4000RPM they should be pretty similar as far as boost goes. Which by your torque graphs, i bet they are. Also, when we were testing one of our boost control methods, we found that too much boost and the ECU doesn't like it. So maybe your single cat exhaust produced too much boost below 3000, and killed the power??

This ECU is going to be a fun one to deal with!

 

Thanks for the clarification. I wish I knew why just changing my exhaust caused the ECU to change it's boost target mapping, but it did it from the first pull out of the garage, like it was instantly adaptive. Greatbear suggested some acoustic interaction, which may be possible. That would be ruled out if the ECU got reflashed for a certain boost level and the car did or did not have the ability to keep it. Time will tell for sure.

Get crackin' on the ECU, I needed a flash like yesterday, LOL

 

Our boost on the street used to peak at around 16psi, now its 19psi, but only sometimes. This is one of the flaws i find with the new car. STRANGE BOOST CURVES. But its the ONLY flaw!! I love the response, and it is way way faster than our R53. Driving them both back to back for a few hours makes me never want to drive the R53. Both have the same basic bolt ons, and make the same basic peak power.

With that said as we get closer to flashing these cars, we will figure out, why it is so "all over the place".
Fun stuff to come!

 

19psig? My car was 15.3 psig peak stock and now 15.6 psig peak with turbo-back exhaust. My stock peak boost is in-line with what Helix13 found on their car. I haven't heard of many others checking their boost pressures. It sounds like your car is a factory boost freak! No wonder yours makes more power, you're running way more boost!

 

On the dyno the most boost we saw was a peak of 15psi, dropping to 13psi, then back to 16psi, then dropping off to 12psi at redline. Then the low boost curves( don't know why they did this) would peak at 11psi, dropping to about 9psi, then climbing to 14psi, then back down to 10psi.

But on the road once and a while i have seen 19psi at low RPM/peak. THis in in 5th or 6th gear on the freeway, and flooring it. So the boost is building so fast that the ECU is not able to control it. At least that is my guess. But normal driving in 2-4th it hits about 16psi, or so.

But this is only peak. After that, the boost curve is a

Peaking at 11psi, dropping to about 9psi, then climbing to 14psi, then back down to 10psi. Because we were logging everything going on in the car, there was nothing we really saw that caused this. Even on the road we noticed these strange occurrences. So needless to say, during the testing, all the “Low boost” runs were removed and not accounted for.

 

I would imagine 19psi should be pretty easy to hit. We'll get spikes of over 20psi pretty regularly with the K03 in the VW/Audi 1.8T applications. Holding at 17-19psi is common on chipped 1.8Ts.

 

Thanks improvius for the bit of vee-dub perspective! It's good to get a feel for the limits of the K03 from experience. Do you know approximately how much wheel hp stock K03 equipped 1.8T's are seeing? This would give us a decent idea of the max flow rate of the compressor, assuming the one on the R56 is similar.

Thanks!

 

Well, a decently-modded (aggressive chip + TB exhaust) 1.8T can put down 200whp and 250wtq pretty easily and still maintain high reliability. Some more aggressive modders have made over 250whp, but you're really punishing your poor little K03 at that point.

 

200whp and 250wlb-ft sounds plausible for sure. 250whp is certainly squeezing alot of air through that little compressor! Thanks for the info!

 

I can't wait till alta comes out with their reflashes and turbo upgrades... not a big fan of piggybacks here.

 

I don't mean to hijack this thread or anything, but there's already like 4 exhaust threads so I didn't want to start another one for a question. I'm probably going to get a custom exhaust built at a local shop here, but I need some tips on what to order and any tips on specifications to the builder. I have a R56 MCS that is completely stock, but my future plans for the engine are going to be almost entirely bolt-on. I have no intention of ever replacing the internals, but an ECU piggy-back or flash are possible options in the future. So with this amount of future modding (probably will never ever see more than 250whp), what would you guys recommend that I get built? 2.75" or 3" (or any other size)? Should I waste my time going turbo-back, or should I only do cat-back? I don't plan on keeping the cats (not too worried about emmissions). Also, what muffler would you guys recommend, as I have no experience with aftermarket exhaust. Lastly, are there any specifications/requests I should give to the builder (i.e. I have heard to make sure that in addition to a stainless steel system, make sure to request that they use stainless steel welds so as to not rust at the welds). Thanks so much for any help you guys can give.

Also, I will have to have it installed by them also, so what do you guys suspect a reasonable cost for build and install should be? Or if you guys think I'd be better off just buying an aftermarket system. Thanks.

 

Did you check out my post about the comparison between my system and Ryan's, its one of the four posts your referring to If you've got any questions, feel free to PM me about them.

 

Well, I've decided to go with a 3" custom system and I was wondering what you guys thought about this muffler:

http://www.magnaflow.com/02product/s...ne=main&id=633

Is it the correct length, etc. Also, does anyone have any experience with www.allexhaust.com because they have this muffler for $106 shipped.

Thanks!

 

I'm not sure its the same muffler because its a $120.00 price difference. As far as the size goes, well, I'd just go out to your car and measure what you've got and then tell the guy on the phone your measurements and what you're using for piping. Keep us updated

 

Well, I would have thought the same thing, but the MSRP listed on Magnaflow's website is so much more than every other site. If you go to any of the dealer's sites that Magnaflow has listed, they all sell it for $127, so the $106 doesn't seem so scam-ish compared to that.

 

That looks like the same muffler I used, but check Jeg's for the best price.

 

Anyone able to give me the quick ABC's of selecting a catalytic converter...I literally am oblivious to all things cat. I know that Ryan used a Dynatech, but I don't know anything about those except that they are much more expensive then a lot of the Magnaflows. What should I be looking for when purchasing a cat(s), and how many would you guys recommend that I incorporate into my system? My earlier post describes what I am going for. Thanks again for all the help guys.

 

Ryan-
As always great info I think in the long run most R56 owners will face the issues we VW owners face with our 2 liter TFSI K03 turbo'd cars. The darn turbo just isn't big enough, in efficency rating, to be able to handle big numbers. It will be interesting to see what develops over the coming months and years for these engines. Can you say 28rs???

The exhaust looks great and will be interested to see what you figure out with more data logging as to why it acts so wonky around 2500.....

 

Thanks a bunch for the kind words!

 

I think in the mid 200's is where the 1.8T applications max out. In the 2.0T apps I have seen mid to high 200s quoted depending on what else has been done. Typically ECU flashes on this engine yield 20hp or so. And as already stated the K03 runs out of gas up over about 4.5k rpms and starts to drop boost pressures.

 

ryan,

nice looking exhaust! and nice car, when you gonna throw a gt28 or 3071 on that thing

 

Does anyone have a boost/ignition map for a stock car? Like boost and timing over rpm? That may help figure this out. Of course we would need that info for Ryephile's car as well.

Ryephile, I would have to say that you're losing all that low-end power because of timing/spool characteristics with the new exhaust and stock ecu. The ecu is probably adding a significant amount of timing in order to help get the turbo spooled up initially to get rid of any turbo lag, however it does this based on a stock car. Once it sees the boost rising faster than what it "knows" is right it reacts by restricting the boost and retarding timing, probably an attempt to prevent the car from overboosting to much and damaging the engine. As for the reason why it's not happening to the other exhausts mentioned, it may be the cat that's being used. i.e. the cats they're using restrict the exhaust just enough to where what backpressure there is prevents the turbo from spooling up as quickly as your's. It's not a definite answer but it could be a possibility.

Also with what is being said about the turbo, I have a feeling that once people start upping the boost to 20-25+psi that engines are going to start popping even with built internals if the stock ecu is used without timing control. I say that because if the turbo really is "running out of breath", so to speak, the ecu is more than likely advancing the timing quite a bit in order to keep the power up.