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Why BMW needs turbo for E54 engine to acheive 306hp?


02202006, 05:36 PM  #89 
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Here is a link to another thread about the actual engine and the lack of valvetronic etc. very interesting and also explains the reason for it being late or a no show to the US. http://www.e90post.com/forums/showthread.php?t=13350

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02202006, 06:24 PM  #90 
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Thanks for the crosslink: so does this mean that Di will replace valvetronic ? I thought it was in addition to it. I can see turbo and valvetroic not getting along well, but DI ?

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02202006, 09:54 PM  #91  
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WTF ..? PLEASE READ CAREFULLY Saintor, How torque works is a FACT. This is not my opinion, but an engineering FACT. Did you even read it. Did you see the formulas..? That link is HOSTED because it was well written and in laymans terms so even dolts like you can read and start to grasp what torque is and does. That article is linked too on almost every Car forum in the world because it does a good job helping starters understand. You completly lost. Your talking abou about gearing and shifting and not about acceleration . Your confusing gearing with torque. No matter what gear your in, you will accelerate based on the torque curve. Leaves gears out of it... or better yet use only ONE gear. Since the next gear will be the same as the last just slower acceleration. Do as I have suggested and READ about torque... Google it if you must. Perhaps in about 1015 years you will understand it. Several of my colleagues still cannot grasp the concept. This isn't to slight you... but your obviously young and still in he adolecant age where YOU believe everything you think. As for the reast of you jumping into the torque debate, plz go back a few pages and see how this developed. I have already provided the proper links and am attemping to coddle this young'n along before getting to technical. Saintor has already made a mistake with his example... but I won't point that out just yet until he counterdicts himself, then i will show him his folly. Garrett Post script: Saintor, do you even know how to read a powerband chart. Can you tell me what car has the 1.8liter turbo... or ANY car your familiar with so was can discuss something tangable to you. 

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02202006, 10:12 PM  #92  
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Aye, and I have not said anything to counterdict that. Saintor is head strong in his belief, so I am helping him along stepbystep and will soon get into that... But first he has to understand that he is wrong, then we can go on to teching him... 

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02212006, 02:17 PM  #93  
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Again, the one who is lost is not the one you thought. Here is a guy (race engine builder) who actually knows what he is talking about. http://www.pumaracing.co.uk/power1.htm Quote:


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02212006, 06:31 PM  #94  
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That has nothing to do with your original statement. Quote:
.. .. Torque = Acceleration. All gearing does is make use of torque to the enduser spacific needs ...! Give me ANY powerband chart of any car... I can tell you exactly at which point THAT car is accelerating it's fastest. Either accept that you don't have a firm grasp of torque... OR you above stement is skewed. I think your getting speed and acceleration mixed up. Acceleration is the rate in which your speeding up. YOUR the one that keeps saying torque has nothing to do with acceleration, remember..? How can you link that when it says exactly what I linked you 3 days ago ..? Did you even read your own link. Mathmatics don't lie. How torque works is a FACT... do you remeber me saying that ..? Any car... no matter who makes it or builds it will accelerate at the rate appropraite to it torque curve.. and you bloody link explains that. 

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02222006, 05:07 AM  #95  
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But you can't ignore gearing. Absolute torque at the wheels is determined by engine torque X multiplication provided by gearing (minus losses within the drivetrain). Comparing two cars with exactly equivalent gearing, one having low torque high HP (a diesel) and the other high torque & low HP. Sure, the former will likely outaccelerate the latter in 1st gear up to around 4000 rpm. But then the former car will have to shift into second gear which has less torque multiplcation whilst the latter car can remain in 1st gear up 'till around 7K rpm. So whilst the former car may have had an advantage initially, it quickly loses steam once it has to shift. If you maximise the use of gears in any car, it will be HP that determines outright acceleration. Yes  in any single gear the torque curve will exactly mirror the rate of acceleration, but outright acceleration doesnt happen in one gear. There is no point in having a car with a peak torque of 700 Nm if it peaks at 1000rpm, and redlines at 2000 rpm. The only reason hightorque at low RPM type cars feel fast in 'everyday' driving is because normally we only drive in the 15003000 rpm range. If we limit our driving to <3000 rpm, then hightorque, lowHP cars such as diesels feel like rockets. But this is an unfair comparison to petrol engines  in order to make the most of a highhp, lowtorque petrol engine, you must take advantage of torque multiplication of low gearing and this can only occur if they are revved to highRPMS. In summary, the rate of acceleration you feel is the torque at the wheels , not the torque at the engine. Torque at the wheels is a function of the engine torque X multiplied by the gearing factor. Highhp, lowtorque carcan take advantage of this by remaining in lower gears and thus providing an overall torque at the wheels curve that will on average be greater than that of a lowhp, hightorque car. 

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02222006, 06:17 AM  #96  
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Check the below the diag of my car 

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02222006, 01:21 PM  #97  
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Saab 95 (258 lbsfr at 1900rpm) and Legacy 2.5GT (250 lbft @ 3,600 rpm). Guess what? Those cars have a reputation for doing not well when matched to an automatic. You can bet your ass that in 12st gear they will continue to pull stonger and stronger as they rev close to peak power. Not a mistake. If you think that a Saab pulls at its strongest at 1900rpm, you are crazy. 

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02222006, 01:54 PM  #98 
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Drives: E91 320d ZSP
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You can't say that horsepower or tourque is the factor that gives the quickest accelereration. Each is a relative factor of the other. If you know one, you can figure out the other at a specific rpm. It can be calculated with this formula:
Hp = rpm x torque/5,252 or conversely Torque = 5,252 x hp/Rpm
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02222006, 02:10 PM  #100  
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02222006, 02:23 PM  #101  
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Give me a chart... 

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02222006, 02:32 PM  #102  
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OMG. The Saab can pull lousy for many reasons, inappropriat 1st and second gear. Poorly chosen rearend...etc. But then your talking about the CAR and not the ENGINE. Saintor, you keep adding and changing your argument. Torque = Acceleration and you keep saying it doesnt... then you keep talking about GEARING. Gearing multiplies torque, thus I have already proven my point overandover. You havn't mentioned Horsepower at all, which coincidentally was what you saying is what made acceleration. 

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02222006, 02:41 PM  #103  
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Hmmmm.... look at the Torque curve. Kinda looks identicle to what your saying hunh ? Not much happens under 2500rpms, but after that the engine starts to pull. At 2820 the 1.8t is near peak torque and pulls along the flat torque curve(black line is stock). Looks like it pulls pretty flat until around 6,000rpms. The rate of acceleration should remain reletively the same from 2820 to 6000. If someone would gmeter this it would prove such. Now as for the modified 1.8t you will be able to feel the RUSH of the turbo as all that huge torque comes barrel down on you. That rush will last until about 3600rpm's and after that the car will still accelerate, but just not at the rate it was. It will slowly dwindle and it will soon be time to grab another gear when your acceleration is less than what it would be in the next multiplier (gear). GMeters and shifting will show this. It's will show acceleration, and it's a great aid to look at when trying to acheive the greatest amount of acceleration because after several runs it will show you illustrate when it best to shift to the next gear. Last edited by Garrett; 02222006 at 02:57 PM. 

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02222006, 03:46 PM  #104  
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And you're right Garett, with my chip the acceleration from 2100 tr/min to the point of Max Torque is increasing, once the highest amount of torque reached, the acceleration get regular until the end of the turbo's action. shifting is done beetween 5'500 and 5'800 tr/min. There is no need to drive at higher revs. 

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02222006, 07:53 PM  #105  
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There is no thing such as "inappropriate gear". For a given gear (what one is irrelevant), the maximum acceleration of the above will NOT happen at 1900rpm (peak torque) on the SAAB, but much later on peak HP. If you maintain that torque=acceleration, this is because you don't understand what is the concept of power and the importance of it. In brief, torque is the answer to the question "Will it be able to handle it?" power is the answer to the question "How fast will it able to move it?". Including acceleration by definition. Torque on a shaft/wheel is what makes the acceleration to happen, in accordiance with the formula F=ma, on a snapshot basis. But over a range of RPM, HP is clearly the determining factor. 

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02272006, 06:04 PM  #106  
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Saintor, you have failed to grasp the concept of Torque. An engine is a stand alone product. It does'nt needed to be hooked to a car to develop HP or Torque. It doesnt need mutliple gears to produce tangable output such as accelerating a car. You have to decouple the engine from the tranny then rebuild it in your mind to understand torque. You keep confusing the use of gearing as a multiplier of torque as POWER . Torque 101: I asked you to produce a hp/tq chart from a car that your familiar with, so i can begine the process of teaching you what torque is and how it does exactly what is known as FACT. I was going to take that graph and go over it and how you are misunderstanding it and GRAPHICALLY show you what acceleration is. A car can accelerate really fast in any gear... but in whatever gear you choose to talk about it will always be accelerating it's fasest at the peak torque... it has to. It connot be any other way. As for you SAAB story (is that the car/engine you own).. please ive me the ENGINE so that I can at least find the HP chart and display it for all to see. Then we can begine your education in earnest. It's obvious you understand engines, but the concept of HP and Tq is somewhat skewed. Quote:
NO, Torque = Acceleration and HP= Speed. I think your confusing the two. 100mph is a 100mph. A car with alot of HP will be able to go faster and possible hit 200MPH. That has NOTHING to do with acceleration. I hope you at least understand this. and i can prove it to you today if you just tell me what car you own. All it will take will be a drive around your block. Garrett 

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02272006, 07:24 PM  #107 
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As usual, you all wrong and the fact you are so stubborn makes you look like a hopeless case. If you think that I have a baccalaureate in mechanical engineering and don't know what is torque, then you are an imbecile.
Again, in an engine, torque is *NOTHING* without rpm. Combination of both defines ... POWER in HP. There is no constant flow of torque. In an engine, it is an addition of all infinitesimal explosions producing infinitesimal amounts of torque that we can correlate to RPM. What matters is always torque AND rpm. I have demonstrated you that no way that a Saab 95 automatic will never pull its strongest at 1900rpm which is the torque peak.... and it has nothing to do with gearing. All SAAB owners will attest. This should gives you a clue. And apparently you didn't read anything in the expert link I provided earlier. 
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02282006, 02:58 AM  #108  
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While you're right to say that in any one gear max acceleration will happen at maximum torque, when we talk about the outright acceleration of any car we are talking about acceleration across multiple gears. Thus the RPM range and gearing of a car become *very* important. According to you, an 82kW Toyota Prius with 400Nm+ of torque at idle accelerates faster than a BMW 330i (with 190 kW and 300Nm). No. Why? 'Cause the rev range of the electric engine in the Toyota Prius is severely limited. While it the 400Nm will provide a hefty 'shove' initially, it will have to shift gears long before the BMW will at which point the BMW will make use of its extended rev range in 1st gear to rip past the Prius. Look at the difference between a 530i and a 530d! 530i: 190kw, 300Nm 530d: 170kw, 500Nm Which is faster from 060 outright? The 530i! Assuming equal gearing (which they aren't...but let's make that assumption for the sake of this example)...the 530d will outaccelerate the 530i up to around 4000 rpm due to its superior torque in that range. But then the 530d must shift, whilst the 530i still has a massive 3000 rpm to continue in first gear! The 530i is thus able to make use of the massive torque multiplication of 1st gear for a longer period, whilst the 530d has to shift into 2nd early (with far less torque multiplication). The result is that overall the 530i is faster. How is this best represented in terminology? Power! The power of a car factors in not only the torque curve, but also how far it is spread over the rev range! For the same reason, the 335i will NOT be a faster car overall compared to the E46 M3 despite a torque advantage of 35 Nm. (Assuming the weights remain similar). *In gear at lower revs* the 335i may have the advantage, but if the M3 is allowed to take advantage of its entire powerband, it will soon put the 335i back in its place. 

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02282006, 08:25 AM  #109  
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I repeat your words .... "Again, in an engine, torque is *NOTHING* without rpm. Combination of both defines ... POWER in HP. OMG. (your an utter retard) And somewhere along the rpm range there is a spot that has the most amount of torque or "peak"... at that exact given moment any car will be accelerating at it's fastest rate under full throttle. Thats why a good flat torque curve is desirable because it make the car more predictable and smoother accelerating. Saintor, Torque is plotted all along the RPM range. I have not suggested otherwise. I ask you a simple question and offered to give you PROOF if you would just give me the model number or torque curve for your precious SAAb you keep talking about. But even without the torque curve for your SAAB I can can definitely prove to you that torque equal acceleration. Put your SAAB in 2nd gear and drive down the road at approx 2,000rpm's (or whatever is actual peak tq is) and PUNCH IT. You'll feel your car surge and throw you in your seat (given that 2,000rpm's is near your SAAB's peak torque). NOW.... stay in the same gear and drive at constantly at 4,500rpm's and PUNCH IT ....! You will not feel the same surge and the feeling of being pushed back in your seat simply because the car isn't accelerating as fast as it was at @ 2,000rpm's (the engines peak torque as you say). OH, it still accelerating, but not as hard as it was at 2,000. if there is a discrepency it could be because of the torque converter (automatic) or limited slip differential...etc. Here the closet i can find to YOUR SAAB. It's a 93 Viggen Torque is the blue line. EDIT: that picture is no longer availbale, but here is another. Torque curve is in green. DO you see the Torque curve...? As the rpms change so do the amount of torque. In this case the maximum torque is somewhere near 4,500rpm's... so I'm not sure if thats the same engine as your SAAB. If it is, then your 1,900 is WRONG. If you can give me model/year or engine code i can display your ignorance even better. Here another Dyno chart from a 2002 93 SAAB. Maximum torque is acheived @ 3,700'ish rpm's. Look > I have yet to find a SAAb that has maximum torque at 1,900rpm's as you have suggested. Garrett Last edited by Garrett; 02282006 at 09:19 PM. 

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02282006, 08:44 AM  #110  
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1st: I'm not compairing engines to engines (or cars to cars). My statement is true for each different engine your are specifiaclly talking about. Your whole arguement is moot, because nobody here is compairing engines.. 2nd: Gearing multiplies torque to the advantage of the engineer who designed the gears(tranny). Wether they are trying to get optimol performance or fuel efficiency.... but in any given gear ANY car will accelerate the fastest at THEIR highest torque... PERIOD ! 3rd: Drag racing is nothing more than using the car torque to the best advantage... meaning choosing shift point that place your engine at the highest torque margins throughout the race (gears), though... high revving engine do have a mechanical advantage over low reving engines when racing because they can wind out the engine and grab higher speeds in any given gear.... BUT for that engine, it still applies to my rules. But when torque drops off... even in a highrevving engine the best possible time to grab another gear is when you know for certain that when you shift and the RPM's drop that the torque is greater than what is was in the last gear. If you don't understand this i can draw a very rough graph for you. But I assume you know this. Garrett Last edited by Garrett; 02282006 at 09:32 AM. 

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