Low end torque starting to bug anybody else?

[BimmerBoomer]

Originally Posted by footie

Do you honestly believe that the new McLaren mp4-24 with it's turbo unit will not be exciting to drive?

The McLaren will redline at 8500 rpm. BMW just needs another 500 rpm to get the straight six to 7500 rpm (and about 1000 rpm on the right hand side of the torque plateau) to match the powerband width of the S65 engine - since it all starts 1000 rpm earlier. The performance potential of such an engine is staggering.

[Gearhead999s]

Originally Posted by footie

Do you honestly believe that the new McLaren mp4-24 with it's turbo unit will not be exciting to drive?

Please deliver one to me for a trail and I will let you know!

It's a sign of the times guys that almost all hi and ultra hi-power performance cars will be making the switch to some form of forced induction or another. I just find it laughable when so many are so negative and openly said that they will never own one. It's as good as saying that they will never again own a new hi-performance car because there will be no other option soon.

Gearhead, have you driven an RS6 yet, or the new X5/6M?

I have owned quite a few turbo vehicles over the years and I am not a huge fan on forced induction for an enthusiasts vehicle that will be used for some track use.For normal road vehicle yes but I prefer the power delivery of a normal induction performance engine expecially when traction condtions are less than ideal if I am driving at the limit.Will I own a new M when it comes?I am not sure but I am not saying that I will not.It will take a test drive to make my mind up.At least I have an open mind on this

No new RS6's for Canada and I think the X M's are just a dumb vehicle that are of little interest to myself.I also feel the same about a Turbo Cayenne

[footie]

Originally Posted by Jim Pearce

The McLaren will redline at 8500 rpm. BMW just needs another 500 rpm to get the straight six to 7500 rpm (and about 1000 rpm on the right hand side of the torque plateau) to match the powerband width of the S65 engine - since it all starts 1000 rpm earlier. The performance potential of such an engine is staggering.

Finally someone is starting to see the bigger picture.

[footie]

Originally Posted by Gearhead999s

I have owned quite a few turbo vehicles over the years and I am not a huge fan on forced induction for an enthusiasts vehicle that will be used for some track use.For normal road vehicle yes but I prefer the power delivery of a normal induction performance engine expecially when traction condtions are less than ideal if I am driving at the limit.Will I own a new M when it comes?I am not sure but I am not saying that I will not.It will take a test drive to make my mind up.At least I have an open mind on this

No new RS6's for Canada and I think the X M's are just a dumb vehicle that are of little interest to myself.I also feel the same about a Turbo Cayenne

I understand that the XMs are dumb but that wasn't the point in my question, I was simply asking if you had driven one to see how you found the delivery of the new turbo engine, that was all. I've driven the RS6 and I felt it was the best example of an FI engine done extremely well and would imagine that the new XM unit to be equally as good.

[330CIZHP]

If you know anything about BMW turbo engines, they lose steam after 5500 rpm. Having a high redline for the sake of high redline makes no sense at all. The samething is being said about the X5 M and X6 M that they like the 335 are completely out of breath after 5500 rpm. Shifting anything after 6000 - 6200 rpm makes the car actually slower because the torque curve has completely gone to hell by then.

That is the trade off of fitting smaller turbos to reduce turbo lag as much as possible. The top end power suffers. The new M5 will have a 6800 rpm redline much like the X5 M and X6 m. The whole point of M division to fit turbos on M cars is to get away from highly engineered, high-revving engines with high output so that the tree-hugger happiness, mass appeal, fuel efficiency and daily drivability could be attained at the cost of high-revving exhilaration.

Case in point, there is absolutely no use of giving a more than 6000 rpm redline on the new turbo FI M3. Making a high-revving turbocharged engine tuned for lots of power up top sacrifices huge low end torque. It takes too much money and also handling the stress, heat and pressure of turbo with high-revving engines is another issue.

If you want to see examples, look at highly tuned monster Supras or Skyline GT-Rs fitted with big turbos and with fully built internals putting down 800 whp and 9000 - 9500 rpm redline. They make no torque whatsoever till 5000 rpm.

All in all, if you think the new M3 will be fitted with small turbos to reduce turbo lag and have a 7000+ rpm redline, you are definitely operating somewhere up in la-la land.

Originally Posted by Jim Pearce

The McLaren will redline at 8500 rpm. BMW just needs another 500 rpm to get the straight six to 7500 rpm (and about 1000 rpm on the right hand side of the torque plateau) to match the powerband width of the S65 engine - since it all starts 1000 rpm earlier. The performance potential of such an engine is staggering.

[Gearhead999s]

Originally Posted by footie

I understand that the XMs are dumb but that wasn't the point in my question, I was simply asking if you had driven one to see how you found the delivery of the new turbo engine, that was all. I've driven the RS6 and I felt it was the best example of an FI engine done extremely well and would imagine that the new XM unit to be equally as good.

No I dont care to as someone might see me driving it I wish we did get the RS6 here but Audi seems to think that we are unworthy of such a fine automobile

[Gearhead999s]

Originally Posted by 330CIZHP

If you know anything about BMW turbo engines, they lose steam after 5500 rpm. The samething is being said about the X5 M and X6 M that they like the 335 are completely out of breath after 5500 rpm. Shifting anything after 6000 - 6200 rpm makes the car actually slower because the torque curve has completely gone to hell by then.

That is the trade off of fitting smaller turbos to reduce turbo lag as much as possible. The top end power suffers. The new M5 will have a 6800 rpm redline much like the X5 M and X6 m. The whole point of M division to fit turbos on M cars is to get away from highly engineered, high-revving engines with high output so that the tree-hugger happiness, mass appeal, fuel efficiency and daily drivability could be attained at the cost of high-revving exhilaration.

Case in point, there is absolutely no use of giving a more than 6000 rpm redline on the new turbo FI M3. Making a high-revving turbocharged engine tuned for lots of power up top sacrifices huge low end torque. It takes too much money and also handling the stress, heat and pressure of turbo with high-revving engines is another issue.

If you want to see examples, look at highly tuned monster Supras or Skyline GT-Rs with fully built internals putting down 800 whp and 9000 - 9500 rpm redline. They make no torque whatsoever till 5000 rpm.

All in all, if you think the new M3 will be fitted with small turbos to reduce turbo lag and have a 7000+ rpm redline, you are definitely operating somewhere up in la-la land.

They should just put huge turbo's on it and have an anti lag system like the WRC cars do.I would like my cars exhaust to be glowing cherry red on the street and backfiring like mad

[footie]

Originally Posted by 330CIZHP

If you know anything about BMW turbo engines, they lose steam after 5500 rpm. The samething is being said about the X5 M and X6 M that they like the 335 are completely out of breath after 5500 rpm. Shifting anything after 6000 - 6200 rpm makes the car actually slower because the torque curve has completely gone to hell by then.

That is the trade off of fitting smaller turbos to reduce turbo lag as much as possible. The top end power suffers. The new M5 will have a 6800 rpm redline much like the X5 M and X6 m. The whole point of M division to fit turbos on M cars is to get away from highly engineered, high-revving engines with high output so that the tree-hugger happiness, mass appeal, fuel efficiency and daily drivability could be attained at the cost of high-revving exhilaration.

Case in point, there is absolutely no use of giving a more than 6000 rpm redline on the new turbo FI M3. Making a high-revving turbocharged engine tuned for lots of power up top sacrifices huge low end torque. It takes too much money and also handling the stress, heat and pressure of turbo with high-revving engines is another issue.

If you want to see examples, look at highly tuned monster Supras or Skyline GT-Rs with fully built internals putting down 800 whp and 9000 - 9500 rpm redline. They make no torque whatsoever till 5000 rpm.

All in all, if you think the new M3 will be fitted with small turbos to reduce turbo lag and have a 7000+ rpm redline, you are definitely operating somewhere up in la-la land.

The rumour is that you can expect something along the lines of 7300rpm, but peak power will be more like that used by Audi (i.e. a plateau of power over a broad rev range). Drive an RS6 or even the S4 and you will see that using the entire rev range is worth while and neither run out of piff.

[330CIZHP]

No they don't! Come on man!!!! Give it up already. This topic is a dead horse. Let this thread go. Audi is pulling out no magic wands here to defy physics.

As the saying goes "there is no free lunch here". Yet, again you have been proven wrong. If you want true high-revving torque and power, you need to build an engine from the internals to be that and it costs a lot of money. Not take a standard low-revving engine and slap a turbo or supercharger on it and call it a day. It just does not work like that. No way!

This tuned 2010 S4 does not make any top end power past 4800 rpm. The torque curve is completely down the toilet after that. Look at this dyno:

The peak torque of 321 ft-lbs is maintained between 3250 and 4880 rpm and then after that all hell breaks lose. The torque completely goes down like a sack of potatos dipping down to only 275 ft-lbs of wheel torque in the next 1000 rpm and then it gets really bad as it is down to a piddly 200 ft-lbs by 7300 rpm. In a matter of just 2000 rpm, it lost more than 100 ft-lbs of wheel torque. You call that a torque plateau??

Originally Posted by footie

The rumour is that you can expect something along the lines of 7300rpm, but peak power will be more like that used by Audi (i.e. a plateau of power over a broad rev range). Drive an RS6 or even the S4 and you will see that using the entire rev range is worth while and neither run out of piff.

[BimmerBoomer]

Originally Posted by 330CIZHP

Audi is pulling out no magic wands here to defy physics.

Audi is subject to the laws of physics, BMW is not.

[330CIZHP]

Originally Posted by Jim Pearce

Audi is subject to the laws of physics, BMW is not.

If BMW were not, it would not be the case to have a crappy down the toilet torque curve of 335 above 5500 rpm. Turbo lag is another thing. I have driven 335 multiple times and after 5000 rpm, it completely begins to die off. Samething applies to X5 M and X6 M. The 6800 rpm and 7000 rpm are there just for show. No need for a 6000+ rpm redline.

[southlight]

Originally Posted by 330CIZHP

If BMW were not, it would not be the case to have a crappy down the toilet torque curve of 335 above 5500 rpm. Turbo lag is another thing. I have driven 335 multiple times and after 5000 rpm, it completely begins to die off. Samething applies to X5 M and X6 M. The 6800 rpm and 7000 rpm are there just for show. No need for a 6000+ rpm redline.

Well, the S63 has more power and more torque at the redline than the S85 has anywhere through its speed band. Who would dare to call that crappy?


Best regards,
south

[330CIZHP]

That is true. However, I was speaking in relative terms looking at how the torque curve falls relative to the rpms. It probably makes much more sense to keep the redline around 6000 rpm and shift where still it makes a lot more torque (and hence offers better torque multiplication factoring in gearing) around 5000 - 6000 rpm than it does between 6000 and 7000 rpm where it loses around 30 - 35% of its peak torque (40% in the Audi S4's case).

Originally Posted by southlight

Well, the S63 has more power and more torque at the redline than the S85 has anywhere through its speed band. Who would dare to call that crappy?


Best regards,
south

[BimmerBoomer]

Originally Posted by 330CIZHP

If BMW were not, it would not be the case to have a crappy down the toilet torque curve of 335 above 5500 rpm. Turbo lag is another thing. I have driven 335 multiple times and after 5000 rpm, it completely begins to die off. Samething applies to X5 M and X6 M. The 6800 rpm and 7000 rpm are there just for show. No need for a 6000+ rpm redline.

I drove a Dinan-tuned 335i 180,000 kilometers. It made 286 foot pounds at the flywheel at 6500 rpm.

[bruce.augenstein@comcast.]

Originally Posted by MVF4Rrider

Sigh

How frustrating when trying to educate the masses...

Y'know, it's one thing to act smug and superior to another participant on the forum (I do it fairly often myself), but to act smug and superior to everybody else on the forum?

Wow, that's impressive!

The thing is, though, it works a bunch better if you're actually correct, and in this case, you're not.

Yes, you're correct in the assertion that a change to more aggressive final drive gearing will yield a gain in torque at the drive wheels at every engine rpm in a given gear, but somehow you equate that to a constant increase in acceleration (compared to the stock vehicle) from any speed to any other speed, and that's just ignorant.

Swamp already laid this out in plain English in note 147 in this string, but let me break it down for you a bit:

If you X-Y graph available torque at the drive wheels with X showing the available torque and Y showing the speed, you'll get sort of a waterfall effect, with a tall torque-shaped mountain at lower speeds in first gear, and successively lower and broader torque-shaped hills at higher speeds from second gear on. Where the curves intersect is the theoretical shift point from gear to gear.

Now do it again, except with the revised gearing. You'll find taller and narrower torque mountains, and if you superimpose the two graphs, you'll find that the geared car has the initial advantage (assuming it has traction), but when the geared car has to shift while the stock car remains in first, the stock car has an advantage - until it too has to shift, and the advantage goes back to the geared car, until the geared car has to shift to third, and then...

Get it? It's a seesaw battle with the early advantage in each gear going to the geared car, which has positive ET implications, but it sure as hell ain't an eight percent difference.

As far as trap speeds go, there is an implication that the geared car may do a little better, but that's not always the case, since trap speed will depend strictly on how much average power was delivered to the rear wheels during the run, and since trap speed varies according to the cube root of power, there will only be very minor changes in that parameter. Again, sure as hell it won't be eight percent, and may in fact be nonexistent.

Next time you trash the forum, better be right, or you look like a fool, as you do on this occasion.

Bruce

PS - All that said, I think a more aggressive final drive might very well be a benefit to the M3 in everyday driving, particularly in high gear out on the highway.

[Gearhead999s]

Originally Posted by Jim Pearce

I drove a Dinan-tuned 335i 180,000 kilometers. It made 286 foot pounds at the flywheel at 6500 rpm.

BFD I have a 15 litre 6 cyl sitting in the back yard that beats that all to hellIts got 400,000 kms on it!

HP 600 (447) @2200 torque 2050ft/lbs (2779) @ 1200

I dont consider that to be very sporting to drive either,but it sure pulls good

[southlight]

Originally Posted by 330CIZHP

That is true. However, I was speaking in relative terms looking at how the torque curve falls relative to the rpms. It probably makes much more sense to keep the redline around 6000 rpm and shift where still it makes a lot more torque (and hence offers better torque multiplication factoring in gearing) around 5000 - 6000 rpm than it does between 6000 and 7000 rpm where it loses around 30 - 35% of its peak torque (40% in the Audi S4's case).

20% in S63's case. It makes plenty of sense to have a higher redline because it allows you to shift later and to keep the engine higher in the speed band in the next gear.


Best regards,
south

[330CIZHP]

Again mentioning what I said to southlight. It is a debate about redline. When you lose over 30 - 40% of your torque in the last 2000 rpm, there is no point in having a 7000 rpm aside from superficial reasons when a 6000 rpm works much better. Got it??

Still compared to the peak of 400+ ft-lbs of wheel torque Dinan typically tuned 335s make, you are much better off shifting at 5500 rpm like I said to southlight and get MORE torque multiplication factoring in gearing than at redline where you have alread lost 120+ ft-lbs of wheel torque.

Originally Posted by Jim Pearce

I drove a Dinan-tuned 335i 180,000 kilometers. It made 286 foot pounds at the flywheel at 6500 rpm.

[BimmerBoomer]

Originally Posted by 330CIZHP

Again mentioning what I said to southlight. It is a debate about redline. When you lose over 30 - 40% of your torque in the last 2000 rpm, there is no point in having a 7000 rpm aside from superficial reasons when a 6000 rpm works much better. Got it??

Still compared to the peak of 400+ ft-lbs of wheel torque Dinan tuned 335s make, you are much better off shifting at 5500 rpm like I said to southlight and get MORE torque multiplication factoring in gearing than at redline where you have alread lost 120+ ft-lbs of wheel torque.

Optimum shift point was about 5800 with the tune, 5500 before. I'm confident the M engineers can get another 500 rpm out of a dedicated high performance engine.

[Gearhead999s]

Originally Posted by Jim Pearce

Optimum shift point was about 5800 with the tune, 5500 before. I'm confident the M engineers can get another 500 rpm out of a dedicated high performance engine.

This still not very pleasing compared to the s65 past 7000.To have street engines pull hard in the upper rpm ranges is what has made the M engines special in the past.

[footie]

If I thought we were going to believe the data from a dyno then I wouldn't have mention the torque and power figures for the S4 and RS6 at all because from experience when discuss things with people that believe in dyno data the discussion goes nowhere fast.

I can tell you that the data is wrong, the two have a flat plateau of power, the RS6 between 6200-6750 and the S4 between 6000-7000. If you happen to have driven both you would know and feel the pull to the redline which doesn't run out of piff.

[footie]

Originally Posted by Gearhead999s

This still not very pleasing compared to the s65 past 7000.To have street engines pull hard in the upper rpm ranges is what has made the M engines special in the past.

At what point would you be happy, 8.5k, 9k, possibly enough 9.5k?

I get the feeling that some here are looking for a bike type charactistics.