B8 S4 - twin turbos, supercharged or straight V8?
01-25-2008, 12:36 PM
#1
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B8 S4 - twin turbos, supercharged or straight V8?
<center><img src="https://www.audiworld.com/news/07/b8-s4-exclusive-preview/header.jpg"></center><p>
Those following the speculation and conjecture around the next generation S4 know that different powerplants have been reported by different publications.
AudiWorld has reported on a V6 twin-turbo configuration: <a href="https://forums.audiworld.com/blog/msgs/2175.phtml">https://forums.audiworld.com/blog/msgs/2175.phtml</a>
Fourtitude has reported that it will instead be a supercharger:
<a href="http://www.fourtitude.com/news/publish/Audi_News/article_3563.shtml">http://www.fourtitude.com/news/publish/Audi_News/article_3563.shtml</a>
and
<a href="http://forums.fourtitude.com/zerothread?id=3647273">http://forums.fourtitude.com/zerothread?id=3647273</a>
Who's right?
In the short term it could be neither according to an off the record conversation we had today with somebody familiar with the development but not authorized to speak publicly.
The B8 S4 is very much previewed by the B8 S5, so much so in fact that it would be a breeze to take the S5's 4.2-liter FSI V8 and drop it straight into the S4. Having driven the S5 extensively we can tell you it is a more capable (and more fuel efficient) V8 than the current model S4 employs.
The biggest issue with continuing with a V8 is CO2 emissions. Based on current regulations manufacturers are essentially tested based on their entire fleet average. This of course takes into account the overall numbers of each vehicle sold. The S4 happens to sell more cars worldwide than most people would guess, meaning putting a V8 in it degrades the overall fleet average (whereas the S5 is much more of a niche vehicle and has less affect).
Audi has therefore explored smaller V6's for this important vehicle. Under a typical emissions testing environment a twin-turbo V6 tends to operate out of high boost for much of the time leading to very V6 like results. This is the best of both worlds - turbo charged power with V6 type emissions readings.
Audi also wants to differentiate between the S4 and the S5 from a powertrain perspective if possible. A V8 for the S5 and a bi-turbo V6 for the S4 makes a lot of sense from a marketing perspective.
So which will it be - turbos or charger? BOTH applications have been studied in depth, however the next generation V6 bi-turbo has been in development for 2.5+ years and is a refined and completely ready-to-go powerplant today, whereas the supercharger is far behind in the development cycle.
We believe that Audi's true preference is to go with a bi-turbo offering, but they are concerned about potential warranty costs having lived through the chip tuning years with the B5 S4's 2.7T. We further believe that a supercharged offering has strong support by a vocal few inside Audi, but no realistic chance of coming to market in this generation S4. Last we believe that it is not outside the realm of possibility that Audi will debut the B8 S4 with the S5's V8 under the hood. We hope it doesn't happen, and that we'll see the bi-turbo as previously reported by AudiWorld.
Timing is a whole different issue, and we admit that we were probably optimistic in our original article. It appears that the B8 S4 will not in fact go on sale alongside the B8 A4 in the fall, but rather will make a fall debut in glorious Paris. History buffs may recall that the B6 S4 debuted in Paris in 2002 and the B7 S4 in the fall of 2004.
Those following the speculation and conjecture around the next generation S4 know that different powerplants have been reported by different publications.
AudiWorld has reported on a V6 twin-turbo configuration: <a href="https://forums.audiworld.com/blog/msgs/2175.phtml">https://forums.audiworld.com/blog/msgs/2175.phtml</a>
Fourtitude has reported that it will instead be a supercharger:
<a href="http://www.fourtitude.com/news/publish/Audi_News/article_3563.shtml">http://www.fourtitude.com/news/publish/Audi_News/article_3563.shtml</a>
and
<a href="http://forums.fourtitude.com/zerothread?id=3647273">http://forums.fourtitude.com/zerothread?id=3647273</a>
Who's right?
In the short term it could be neither according to an off the record conversation we had today with somebody familiar with the development but not authorized to speak publicly.
The B8 S4 is very much previewed by the B8 S5, so much so in fact that it would be a breeze to take the S5's 4.2-liter FSI V8 and drop it straight into the S4. Having driven the S5 extensively we can tell you it is a more capable (and more fuel efficient) V8 than the current model S4 employs.
The biggest issue with continuing with a V8 is CO2 emissions. Based on current regulations manufacturers are essentially tested based on their entire fleet average. This of course takes into account the overall numbers of each vehicle sold. The S4 happens to sell more cars worldwide than most people would guess, meaning putting a V8 in it degrades the overall fleet average (whereas the S5 is much more of a niche vehicle and has less affect).
Audi has therefore explored smaller V6's for this important vehicle. Under a typical emissions testing environment a twin-turbo V6 tends to operate out of high boost for much of the time leading to very V6 like results. This is the best of both worlds - turbo charged power with V6 type emissions readings.
Audi also wants to differentiate between the S4 and the S5 from a powertrain perspective if possible. A V8 for the S5 and a bi-turbo V6 for the S4 makes a lot of sense from a marketing perspective.
So which will it be - turbos or charger? BOTH applications have been studied in depth, however the next generation V6 bi-turbo has been in development for 2.5+ years and is a refined and completely ready-to-go powerplant today, whereas the supercharger is far behind in the development cycle.
We believe that Audi's true preference is to go with a bi-turbo offering, but they are concerned about potential warranty costs having lived through the chip tuning years with the B5 S4's 2.7T. We further believe that a supercharged offering has strong support by a vocal few inside Audi, but no realistic chance of coming to market in this generation S4. Last we believe that it is not outside the realm of possibility that Audi will debut the B8 S4 with the S5's V8 under the hood. We hope it doesn't happen, and that we'll see the bi-turbo as previously reported by AudiWorld.
Timing is a whole different issue, and we admit that we were probably optimistic in our original article. It appears that the B8 S4 will not in fact go on sale alongside the B8 A4 in the fall, but rather will make a fall debut in glorious Paris. History buffs may recall that the B6 S4 debuted in Paris in 2002 and the B7 S4 in the fall of 2004.
01-25-2008, 03:05 PM
#4
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I will say it again.
I am pretty sure by reading audi market research materials that the B8 S4 will be a V8, and that we will see a 3.0L twin or biturbo in the A4.
Warranty concerns can be addressed by proper cooling.
Warranty concerns can be addressed by proper cooling.
01-25-2008, 05:44 PM
#5
i know it hasn't been done before, but could an S model switch engines mid-lifecycle?
Mercedes has done this with AMG models, going from the C32 to C43 and E55 to E63. Of course, their naming system allows them to be classified as different vehicles.
Is it possible that Audi may debut the S4 with the V8, and then switch both the S4 and S5 to a forced induction V6 in 2-3 years? It could be introduced at the same time as longitudinal DSG.
Is it possible that Audi may debut the S4 with the V8, and then switch both the S4 and S5 to a forced induction V6 in 2-3 years? It could be introduced at the same time as longitudinal DSG.
01-25-2008, 06:09 PM
#6
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the B8 S4 will not have the same engine as that in the S5
there would be no point to the various sightings of a maroon red S4 being tested as we speak in sweden. which you can see over on RS6.com.
they would have also introduced it alongside the new A4 when that was introduced- like the A5/S5.
they would have also introduced it alongside the new A4 when that was introduced- like the A5/S5.
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01-25-2008, 06:32 PM
#8
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Thread Starter
I only agree with some of your logic
Yes, if they were going to do same engine they very easily could have brought S4 same time as S5. but in terms of testing in Sweden or anywhere else it doesnt mean anything. I guaranty they have tested the 3.0 liter bi-turbo engine extensively - it is ready to go if desired. Doesn't mean for certain that we'll see that car tho... testing is testing.
01-25-2008, 06:39 PM
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Can someone please exlain this desire for turbos?
Not ever owning one and only owning the V8 version, is there really an advantage stock for stock?
I say stock for stock because I don't really see the point of buying the car only to spend thousands of dollars buying aftermarket parts to put on it only to void the warranty.
Do the twin turbo cars have the same lag that the 2.0T A4 does? If so, no thanks.
Please educate me.
Eric.
I say stock for stock because I don't really see the point of buying the car only to spend thousands of dollars buying aftermarket parts to put on it only to void the warranty.
Do the twin turbo cars have the same lag that the 2.0T A4 does? If so, no thanks.
Please educate me.
Eric.
01-25-2008, 06:52 PM
#10
AudiWorld Founder
Thread Starter
Re: Can someone please exlain this desire for turbos?
Two smaller turbos generally have smaller lag than a single one. V6 is more fuel efficient and lighter V6 less CO2 emissions. Bi-turbo performance can be similar to V8 but does allow performance upgrades, whereas V8 relatively hard to tune if you are So inclined.