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10-12-2010, 06:51 PM | #89 |
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Just to clarify a couple of things I have seen which are either incorrect or wrong in general with the discussion about supercharging, and in specific to the S4 after some research:
- 7,200 RPM is not fast for a roots type supercharger - The engine and supercharger are not spinning at the same RPM anyway so the above comment is moot - At engine redline, the TVS supercharger (which is a roots style, but not like a roots in many ways) spins at 18,000 RPMs, so you were off by over 100% - The supercharger has an internal bypass valve, which recirculates the already boosted air back into the screws again, so by using the bypass, there is indeed less stress on the supercharger in the stock tune , since it is not having to compress as much air with the bypass opened. - The bypass is a way to mitigate the amount of boost, not a protection method that keeps the supercharger from blowing up - The TVS R1320 on the S4 is warrantied and rated to 18,800 RPM's steady use with burtst to 21,000 RPMs, so Audi's implementation is well within tolerances, even if the bypass valve was a saftey blowoff type valve - which it is not. - While the TVS R1320 is rated at 21PSI, even the tuners have not been able to eek more than just under 13PSI out of it, likely due to it operating out of the efficiency area mentioned by jdgamble. - The engine never sees 21 PSI of boost (as previously mentioned) not at 5K not at all ever. It maxes at about 11-12PSI at 5K, and grandually builds after this to redline. Reference, the tuner's own graph: Just thought it would be good to clear up any misinformation, since some of you appear to be arguing over false information. |
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10-12-2010, 07:26 PM | #90 | |
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You must be one of those technical types to register just for this post!
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10-12-2010, 07:44 PM | #91 | |
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2. Here in the tri state area I've been driving RWD cars for a good 10 years. The AWD argument really doesn't fit as well because a dedicated set of winters is better than AWD with crappy all seasons (I know we will both agree on this) but in harsher climates AWD does make sense. 3. I'd never let my wife/SO drive but that's just me 4. Subjective 5. I thought about this route but having to worry about another car + insurance made less financial sense than the $13k price gap you were bringing up. 6. Subjective. I personally do not like Audi interiors. 7. No car is an investment. Unless it's a classic. |
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10-12-2010, 07:50 PM | #92 | |
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As to the effciency, yes and no, this is a slightly new animal, trypical roots have a 60 degree twisted screws, these have 160 degrees of twist in the screws, as a result they have sweet spots where the efficiency rises, peaks and drops. There are lots of maps of this on the Eaton site (maker of this particular supercharger). Here's the one pertinent to the one on this car, the colors show increasing efficieny as they darken, with the scale also reflecting supercharger RPM's and the pressure ratio: It looks to me like there could be a couple of reasons this one doesn't push the kind of pressure it's rated at, but these are guesses: - They wanted more torque/power/grunt down low, so they have this spinning faster down low, which puts it out of efficiency ranges near redline as a result of getting into the meat of the boost down low - The displacement of this unit is not well matched to the engine's ability to take in larger volumes of air as the engine spins faster while the unit's efficiency starts to drop While I also have not data to back it up, it does stand to reason that putting more boost and therefore more fuel into the engine over what was there stock, as well as advancing of the timing by the tuning company will certainly put more stress on the engine and components - if this will that result in any sort of measurable drop in reliability remains to be seen. |
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10-13-2010, 07:24 AM | #93 |
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10-13-2010, 08:12 AM | #94 |
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The S4 as i have seen with many of my friends has poor reliability. The resale value is just the worst where I live as well.. However the new rs5 seems to be interesting..
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10-13-2010, 08:42 AM | #95 | |
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Why not save even more money and buy a Suzuki 4wd??? It will stand as much of a chance as your S4 (in overall performance) of beating the M3 in any real comparison. Are you planning on coming back in 2 years when you get your hypothetical 997 to tell us about how much better it is as a DD then the M3? Last edited by Advskier; 10-13-2010 at 09:26 AM.. |
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10-13-2010, 09:46 AM | #96 | |
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He said the S4 is his wife car in fact...troll....probably he doesn't have driving license as yet
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10-13-2010, 09:49 AM | #97 | |
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Yeah, you take the $13k your dad saved when buying the S4 instead of the M3, and you're gonna be so successful and buy a 997 turbo from your $13k investment return...give me a break.
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10-13-2010, 10:27 AM | #98 | |
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you remind me of footie.
anyway, I see three different kind of trolls on this forum and mostly coming from audi/porsche (same company). 1. uneducated audi trolls who would put anything audi above bmw. 2. educated audi trolls who like to bring up that they presently/past own an m3 so they can express why audi is better based on their experiences. 3. crazy trolls who would just call everybody fanboys as soon as they praise the m3. ridiculous because after all this is a bmw forum and people praise the m3 because they think it is the best car for them. Quote:
Last edited by graider; 10-13-2010 at 10:41 AM.. |
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10-13-2010, 12:32 PM | #99 | |
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10-13-2010, 03:16 PM | #100 |
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I have to say, living in Toronto which has some nasty winter and having driven AWD and RWD comparably equipped cars:
AWD as a safety feature is highly over-rated. Most accidents and mishaps in the snow have everything to do with cars not being able to stop in time. Thankfully, all vehicles are equipped with All Wheel Braking systems, so with a good pair of snow tires, a RWD car will be fine in the snow. Many people here in SUVs think they are immune to winter driving conditions and end up rear-ending someone. I have to say I have full confidence driving my RWD M3 with dunlop wintersport 3D tires in any kind of conditions we get here in Toronto. Bear in mind this comment is applicable to city driving, not rally-crossing! Also, that this is purely a comment on AWD being a big safety feature in bad weather. I quite like the B8 s4 and might consider it for my next car once the M3 lease is up! |
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10-13-2010, 05:03 PM | #101 | |
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Edit: Here's the data I remember seeing: http://www.m3post.com/forums/showthread.php?t=419634
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10-13-2010, 05:15 PM | #102 | |
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Contrary to what people like you would have everyone believe, just because the M3 can snack on cars like S4's on a race track, they are not a track car. They are BMW's top of the line 4 passenger 3 series sedan/coupe. It is a street car. As to your idiotic torque argument, do a little reading because any informed enthusiast already knows about the M3 winning torque arguments all over THIS site, as well as in every publication. BMW does not market the M3 to be only better than anything on a track, since only the smallest percentage of them end up on a track. It very simply, is the best all around performance sedan you can buy in it's price range. Argue all you want, but I trust every major car publication and TV review more than your ignorant opinion. Now the one area you might have an advantage on all of us here. Please tell us how by saving $13K and purchasing an inferior car, you can turn it into a 997 Turbo in 2 years. Assuming your wife gives you permission Does she pick out your cloths for you as well? You might not know jack about cars, but you must be a rocket scientist when it comes to investing. |
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10-13-2010, 05:25 PM | #103 | ||
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PS - I don't think anyone is really picking on the S4... They're picking on YOU. It's because you are an easy target. I can't believe you are still even on this post. I think we're up to about 8 posts suggesting that you pull your head out of your ass. You're embarrassing yourself.
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10-13-2010, 05:27 PM | #104 |
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Wow... Make that 10. In the time I wrote my post, 2 more direct (and negative) responses to MERCSUk. I think it's time for a new screen name little guy!
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10-13-2010, 09:28 PM | #105 | |
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nobody here disagree that both are great in different area, but the point here is for most people, the m3 is the better car / more special car and they would choose it over the s4. myself included. is that somehow wrong? if you don't believe me, go back and read all my posts. i say it again. if money is not an issue, i would buy the m3 over the s4 everyday. don't care if it is faster than the m3 in straight line or how much faster it is with a chip. the same can be said for a 335i. |
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10-13-2010, 10:24 PM | #106 |
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It's funny, how to the average Audi owning troll who visits an M3 site, every M3 owner is a fanboy.
And it's equally funny, how they all say the M3 is a better car, except where it counts. Isn't there a good Audi forum? |
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10-14-2010, 07:55 AM | #107 | |
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Get lost.
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10-14-2010, 09:02 AM | #108 |
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I've seen the light. the S4 is clearly better than both the M3 and the 335i. So does anyone want a mint condition E90 M3?
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10-14-2010, 09:20 AM | #109 |
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Thanks to Mersuck
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10-14-2010, 10:10 AM | #110 | |
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But you are absolutely correct. The S4 is a vastly better DD than my M3. I can hardly stand to get in the thing, and every time I see an S4 or 335 I can barely control my envy. When I see an S4 or 335 I run in fear, because for all I know it might be "modded". I even went so far as to ask several S4 and 335 owners if they would do a direct trade, but they were all to smart to take me up on it. Even if I offered to throw in some cash. I guess I'm stuck with this POS for now. But eventually I hope to trade up for an S4, and maybe (like you) tell everyone how I am saving for a 997 Turbo, which is a real car. |
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