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01-01-2008, 07:10 PM | #45 | |
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More likely a packaging issue.....see how tight the S65 / S85 engines are?? No room.
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01-01-2008, 11:31 PM | #46 | |
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At the rpm where each (E46s) have peak torque (4900) the torque figures are straight from BMW specs. The peak torque increase was (273-269)/269 = 1.5%. But developing more torque at higher rpms is more important than developing a great peak torque percentage increase. This is basically saying hp is more important than torque. Indeed the torque gains (as a percentage of base) at the rpm of peak hp are equal to torque gains (again on a percentage basis). (360-343)/343 = 5% just as (239-228)/228 = 5% Anything you are not sure of here? So I agree with you that enhancements to the E92 M3 for modding or by BMW for the CSL will not do much to the peak torque. Yet I disagree that there is almost no torque to be had. One needs to qualify the torque curve not just peak figures, which seems to be what you did in your original post. BMW should be able to get at least 5% more torque at the rpm of peak hp, hence 5% more hp, through breathing enhancements alone. That would be 440 hp (441 for the sticklers and that is based on 420 hp not 414...). I'm guessing by raising the redline to 8500-8600 and/or by doing a bit better than the 5%, we will see 450 hp. |
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01-02-2008, 12:02 AM | #47 | |
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As I have said repeatedly no excuses for BWM on this one. |
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01-02-2008, 03:55 AM | #48 |
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01-02-2008, 04:46 AM | #49 | |
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Best regards, south |
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01-02-2008, 11:45 AM | #51 | |
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If it is not a packaging issue, it could be a development issue. Remember the S65 is based on the S85 so there won't be too many changes. If DI was not available for the S85 then it wouldn't be available for the S65 either. Who knows..... In the end it is about showing off your taillights.
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01-02-2008, 12:53 PM | #52 |
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@south: Isn't that like arguing generations of fuel injection - absolutely splitting hairs. FI is FI, DI is DI.
@T-bone: Indeed showing off your taillights is more important than having DI. Just fun to dive into all of the details and speculate about the various suppliers. |
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01-02-2008, 01:22 PM | #53 | |
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But hey it's a DI, and since DI is DI, yeah, you're right: Audi has it, BMW not. Best regards, south |
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01-02-2008, 05:51 PM | #54 | |
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From what I read, the DI implementation in the RS4 V8 destroys the oil as well. Not sure it is of much BENEFIT, as South said.
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01-02-2008, 06:35 PM | #55 | |
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they did not yeild more torque...beyond the associated HP increase... and I'm guessing they only got that at the top end...peak T increased by only 1.5%... increased volumetric efficiency... if they would have raised HP 5%, and torque 10%, then I would be impressed...the only real way to that is with compression (mep) or displacement, both of which remained the same... do you have the factory csl power graph? |
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01-02-2008, 06:38 PM | #56 | |
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BMW will do it when the time is right: cost effective reliability more refined technology (let someone else suffer the growing pains) proven effectivness...right now, the gains are negligable... |
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01-02-2008, 06:46 PM | #57 | |
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DI is really good for leaning out an engine for economy today..... As we know, BMW M doesn't give a flying &^*( about fuel economy
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01-02-2008, 06:48 PM | #58 | |
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The money shot...
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01-03-2008, 11:17 AM | #59 | |
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01-03-2008, 11:27 AM | #60 | |
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@13: Not exactly correct. The RS4 is 4.163 l which makes it 101 hp/l (rounding up from 100.89). Sure BMW wins hp/l but Audi wins tq/l, 76.1 vs. 73.8 (note my previous tq.l calc for the RS$ used an even 4.20 l). Both are difficult to obtain from an engineering perspective and both are reasonable measures of great engine design. Again I think they are saving some room for the CSL, maybe even a mid life power bump. |
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01-03-2008, 11:33 AM | #61 | |
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Defo. If and when you hit the red-line flat-out, you will find this very easy to believe. |
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01-03-2008, 06:23 PM | #62 | |
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If you can not prove the Audi system is not good or only offers marginal benefit you shouldn't claim so. |
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01-03-2008, 06:35 PM | #63 | |
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Do you mean instead of "easy" above, "hard"?? Thanks for rubbing it in about the "if and when"... |
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01-03-2008, 06:57 PM | #64 |
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No worries: without doing the maths, I'm guessing someone either double converted from metric or assumed 4.2l capacity.
No, I don't - driving the car you feel like the engine has loads more to give. The subjective experience (wrong, I know) is that the acceleration actually increases all the way to the red line. Not trying to rub it in at all - I hope you get your turn very soon. |
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01-04-2008, 10:11 AM | #65 | |
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We had exactly this discussion already some time ago here: http://www.m3post.com/forums/showthread.php?p=1222664, and that's what I want you to refer to. It's a very interesting discussion with an RS4 owner who himself said that the benefits over a conventional (manifold injection) engine are "small." Autobild had a comparison between M3 and S5, the S5 did need more gas than the M3. Best regards, south EDIT: The M5 has a better tq/l ratio than the RS4... Last edited by southlight; 01-04-2008 at 10:40 AM.. |
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01-04-2008, 12:59 PM | #66 | |
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Although that RS4 owner seems very knowledgable about Audi and DI systems in general, I don't think his opinion that the benefits of the system are small can be taken as gospel. Again since, the answer to the question of if Audi would implement such a system with small or marginal benefits, is no, then we are left with having to trust that Audi engineers are top notch and that there were a combination of economy, performance and price beneifts that warranted the inclusion of the system. And since the system is likely more ewxpensive than a traditional system the cost accountants would have shot it down in a flash if it did not offer some quatifiable benefits. Assuming anything else is really marginalizing the professionals at Audi. Despite all of the nitpicking about the subtleties of the systems, first gen., seconds gen., US vs EU systems, etc. Audi is ahead of BMW, period. You seem to have an immense problem admitting this in any degree at any time. Lastly isn't comparing mpg across different models from different manufacturers a fairly feeble attempt to prove that Audi's DI system does not offer efficiency benefits? |
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