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08-21-2007, 07:41 AM | #23 |
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http://www.dragtimes.com/forums/inde...showtopic=7760
Not saying it is a fraud, but it's fairly suspect, for numerous reasons that are being questioned on dragtimes and on e90post. |
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08-21-2007, 12:19 PM | #26 | |
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08-21-2007, 02:26 PM | #28 |
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I've been around the VW scene for awhile, and we own both a 1.8T and a newer 2.0T. The gains from chipping turbo motors are impressive, usually, but more often come in the form of mad torque down low, with a more modest hp gain up top. The problem is the small turbos just can't move more than about 10psi of air up at higher revs, or even if they can they simply heat up and become hairdryers, lowering power output.
So what you end up with is a diesel. Mad torque down low, and short shift around 5000-5500 to get back to the mad torque. This is exactly how the 2.0T's react (the 1.8Ts are a little different, as many were software limited up top... So most chip them to get back their upper rpm range). I don't think I'll chip if I buy a 135, just as I haven't chipped our 2.0T. Now a turbo swap would be interesting. Those turbos are TINY! What are they? |
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08-21-2007, 07:03 PM | #30 |
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Just an FYI...Seems that a few people are under the impression that increasing boost puts a strain on the turbos. This is not correct. Increasing boost puts a strain on internal engine parts that are subject to xxpsi. The speed at which the turbos spin (and how much wear and tear is placed on them) is directly related to the RPMs of the engine. As the engine revs the exhaust gases exit more rapidly and with more force spinning the turbos faster and faster. Increasing the boost will not affect how fast they spin. Boost is controlled by adjusting the waste gate to let less air leak out thus increasing the pressure entering the engine. Small turbos produce boost at lower rpms but are unable to keep up at the higher rpms. you can see this on the dyno graphs as the power drops off at a certain rpm.
Hopefully this is informative for anyone researching this stuff... |
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08-21-2007, 08:46 PM | #31 |
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Helpful info... I was thinking the same thing, but I wasn't confident enough to be certain.
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2010 135i Coupe | Black Sapphire Metallic | Red Leather | Poplar Grey Wood Trim | 6MT | Premium pack | M Sport pack | Heated Seats | HK Premium sound | USB | Smartphone integration | Automatic high beams
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08-21-2007, 11:53 PM | #32 | |
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08-22-2007, 06:51 AM | #33 | |
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A wastegate sits on the exhaust side of a turbocharger. When it opens, it allows gases in the exhaust stream to bypass the vanes of the turbocharger, thus preventing the turbo from spinning faster, and regulating the amount of boost the turbo is providing. When the wastegate is allowed to stay closed, those gases flow towards the exhaust side of the turbo, hit the vanes, and cause the turbo to spin more quickly. Turbo spins faster = more boost. When the turbo spins faster, it creates more heat. As long as you stay in the efficiency range of your turbo, the intercooler can cope with the additional heat in the intake air, and the engine's cooling systems can compensate for the greater amount of power created (and thus, heat) there is no real issue... As long as you can get enough fuel in. That can problem with "chipping" very aggressively; either the fuel pumps or the injectors can't keep up, and you can have a severely lean condition and a BOOM. More in a minute to answer the other poster's Q. |
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08-22-2007, 07:15 AM | #34 | |
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Tuners nowadays have a variety of ways to increase power over stock. In a modern turbo engine, the way to biggest gains is to increase the boost at a given rpm. Increasing boost causes more air to go in, which the ECU compensates for by adding more fuel, which means more power. Now, with just a "chip" tune, you are limited by the physical characteristics of the engine. With a stock intake, exhaust, fuel pump, injector, and turbo setup, there are some finite limits. Usually, the factory is conservative, for the reasons above, and a much greater amount of power can be made; especially at lower rpms. Why is this? Manufacturers nowadays are striving for turbo engines that feel just like their naturally aspirated counterparts, or as close to them as possible. This means that it is common to use very small turbos--a small impeller has less mass, spins up more quickly, and thus cuts down on turbo lag and the time it takes to fully "spool" or provide boost. For the N54, BMW used two tiny turbochargers for this reason, and it is very effective--max torque/boost is hit at 1400 rpm (according to BMW). This is incredibly low... For instance, the new VW/Audi 2.0T's, which are considered virtually "lag free" and "quick spooling" doesn't produce max torque until about 2100 rpms. The Subaru STIs and Mitsu EVOs of the world don't produce max torque until over 3000 rpms. This is directly related to turbo size. Think about how a turbo works: the exhaust pulses spin the turbine. At 2500 rpm, the engine is creating fewer exhaust pulses than, say, 5000 rpm. In the STI/EVO, there are not enough exhaust pulses to spin the bigger, heavier turbine up to full speed at the lower RPM, and thus less boost is created as compared to the BMW N54. But this has a tradeoff; at 5000 rpms, the small turbos on the BMW are spinning very fast, and the lack of area on the vanes of the turbochargers is starting to limit the amount of boost the can produce. Think of a fan (like the kind you sit on your desk): the larger the blades, the more air it can push. So... on a small-turbo engine, max boost is hit very quickly and at higher rpms the turbos eventually can no longer produce as much boost. What a chip tuner will do, in many cases, is ask for more boost from the turbos--sometimes ask for as much boost as the turbos can physically produce. Oftentimes, you can get a LOT more boost out of a stock turbo setup at lower rpms. The manufacturer usually doesn't "go there" because of the tradeoffs mentioned above, but the chip tuner can. However, the stock turbos can only give so much at high rpms, so the gains die off. With the tiny turbos on the N54, gains up top will never be huge. Even assuming the stock intake and (especially on a turbo car) downpipe/exhaust isn't designed for max power, and replacing them to free up breathing, you will eventually hit the limit of the stock turbos--and maybe the fuel system. The N54 "chipped" will make huge torque, but not massive HP gains. What does this mean for durability? Who knows, it's too early to tell. I, like you, would worry about the strength of the stock internals and drivetrain. On the VW MKV's, the new DSG wasn't designed to handle mad torque, so some folks have had issues (unlike the manual tranny users) after boosting far above stock levels. And that's in a relatively short timeframe--who knows what will happen after 5+ years of more torque than factory spec. Add to this the HEAT of the N54. This concerns me. The reported oil temps of folks driving the 335's are very concerning; these engines run VERY HOT. Upping the boost will create more power, more power means more heat. This will certainly wear components more over the long haul. Whether this makes any appreciable difference in the life of the car remains to be seen. Hope this helps a bit. |
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08-22-2007, 09:01 AM | #35 | |
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08-22-2007, 10:02 AM | #36 | |
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I really like the stock specs of the N54 and what BMW wanted to do with it. Keeping the power low, no turbo lag, smaller TTs. So I am for turning up the boost, but I realize that those parameters will be compromised a bit. I will just have to see what happens in the real world when I get one, and what I'm willing to do. At this point a modest chip tune and a LSD are really all I'm looking at. Gutting down pipes, hi flow cats, entire exhaust, larger turbos, ect. ect... is a play ground I don't care to play in. Modding my LGT is easy and not as worrisome. Blowing up a brand new N54 is not economically viable for me:wink: |
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08-22-2007, 12:33 PM | #37 |
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That's impressive! I would LOVE to get the Dinan tune/catback once they offer it for the 135i.
Woot for OSW! I'm gonna be going to that track with my car club in the next couple months.
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08-22-2007, 01:12 PM | #38 |
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Might want to re-read things here, and from the links. This was pretty much proven that it was a fraud.
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08-22-2007, 10:46 PM | #39 | |
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Boost pressure most certainly has an affect on turbo rpm. If you knew how to read a compressor map you'd know that if you raise the boost pressure at any given engine rpm the turbo rpm also increases. This isn't necessarily a bad thing. Usually the OEMs tune conservatively and leave some performance on the table. It should be possible to raise the boost some while staying within the rpm limits of the turbo. Also I would be more concerned with EGTs. Usually on a lightly modified car one will exceed the EGT limit of the turbo before the rpm limit. If you’re thinking to yourself this guy has one post, what the hell does he know, I should say I work for a prominent Porsche/Audi tuner and turbo cars are our specialty. I personally can't wait to see what the 135i can do and will definitely be taking one for a test drive |
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08-22-2007, 11:28 PM | #40 | |
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08-23-2007, 05:39 AM | #41 | |||
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Tiny is right. Quote:
Ever wonder why you see those pictures of turbo piping red hot? The exhaust manifold pre-turbo is under pressure and that pressure runs linear with intake pressure. The more pre-turbo pressure you see the more intake pressure you will get. However pressure also = heat and you can't have too much of that in your exhaust manifold other wise you get detonation/pre-ignition. To cool that heat you need more gas but to add more gas you need more air flow. To get that air flow you need more efficient turbines. Its a kind of a symbiotic relationship but what it really comes down to is.. power = flow boost = resistance to flow The key is to have the highest possible intake charge density at the highest possible pressure. I know you were corrected by ducati but i thought i would re-iterate for a broader possible understanding. I posted my thoughts on what would flow well on the N54 in this post.. Quote:
Imo the N54 is going to have a leg up on the competition because of its high compression. It will spool beasts much easier and still have a broad powerband.:roundel: ~Zak |
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