Ok Bigbadbull, turbo lag question from other thread
02-02-2009, 03:43 PM
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Okay, so I went out and drove the car and did the test you described...
Got up to speed, (~64 in 4th gear @ 3,000), let the rpms drop to 1500-1800 and then floored it.
What I found was:
-The car accelerated more slowly, than if I had floored it from 3000+ rpms.
I would think that that is due in part to the inertia of the flywheel at lower rpms.
-The torque didn't "kick in" at a certain rpm, like boost was kicking in, as is referenced in other posts, but seemed to be relatively flat.
Help me out here. Is this the lag that you're referring to?
I've never owned a TT car before, so I don't know the difference I guess. My 99 528 was obviously NA, and although there is much more power in the 535 vs the 528, the "curve" seems to be relatively the same. Don't most cars, even NA ones, have some bog at low rpm WOT?
Got up to speed, (~64 in 4th gear @ 3,000), let the rpms drop to 1500-1800 and then floored it.
What I found was:
-The car accelerated more slowly, than if I had floored it from 3000+ rpms.
I would think that that is due in part to the inertia of the flywheel at lower rpms.
-The torque didn't "kick in" at a certain rpm, like boost was kicking in, as is referenced in other posts, but seemed to be relatively flat.
Help me out here. Is this the lag that you're referring to?
I've never owned a TT car before, so I don't know the difference I guess. My 99 528 was obviously NA, and although there is much more power in the 535 vs the 528, the "curve" seems to be relatively the same. Don't most cars, even NA ones, have some bog at low rpm WOT?
02-02-2009, 03:46 PM
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In 4th gear when you floored it how long did you floor it for? If you did a 3rd gear run you don't feel a sudden surge?
Michael
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Originally Posted by ADD' post='783543' date='Feb 2 2009, 04:43 PM
Okay, so I went out and drove the car and did the test you described...
Got up to speed, (~64 in 4th gear @ 3,000), let the rpms drop to 1500-1800 and then floored it.
What I found was:
-The car accelerated more slowly, than if I had floored it from 3000+ rpms.
I would think that that is due in part to the inertia of the flywheel at lower rpms.
-The torque didn't "kick in" at a certain rpm, like boost was kicking in, as is referenced in other posts, but seemed to be relatively flat.
Help me out here. Is this the lag that you're referring to?
I've never owned a TT car before, so I don't know the difference I guess. My 99 528 was obviously NA, and although there is much more power in the 535 vs the 528, the "curve" seems to be relatively the same. Don't most cars, even NA ones, have some bog at low rpm WOT?
Got up to speed, (~64 in 4th gear @ 3,000), let the rpms drop to 1500-1800 and then floored it.
What I found was:
-The car accelerated more slowly, than if I had floored it from 3000+ rpms.
I would think that that is due in part to the inertia of the flywheel at lower rpms.
-The torque didn't "kick in" at a certain rpm, like boost was kicking in, as is referenced in other posts, but seemed to be relatively flat.
Help me out here. Is this the lag that you're referring to?
I've never owned a TT car before, so I don't know the difference I guess. My 99 528 was obviously NA, and although there is much more power in the 535 vs the 528, the "curve" seems to be relatively the same. Don't most cars, even NA ones, have some bog at low rpm WOT?
02-02-2009, 03:54 PM
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I ran it up from 1500-1800 up to 4500+.
Back down to 3000, floored it again, where I found that it is more responsive.
Back down to 1800, floored again, and it accelerated more slowly, but nothing I would consider out of the ordinary for any manual tranny in 4th at 1800 being floored. Ran it back up to 4500 or so.
The car feels more responsive in the 3000 and up range, but it feels just like it is in the sweet spot of the power band. Run it up to 3500, let off the gas, and get back on it, and it does feel quicker. I thought that was just the power band, not the turbos.
In any case, I shouldn't be too concerned. I like the car just fine, and frankly, it never gets down below 2500 while driving. It was a painful exercise to let it get down to 1500 in 4th.
Back down to 3000, floored it again, where I found that it is more responsive.
Back down to 1800, floored again, and it accelerated more slowly, but nothing I would consider out of the ordinary for any manual tranny in 4th at 1800 being floored. Ran it back up to 4500 or so.
The car feels more responsive in the 3000 and up range, but it feels just like it is in the sweet spot of the power band. Run it up to 3500, let off the gas, and get back on it, and it does feel quicker. I thought that was just the power band, not the turbos.
In any case, I shouldn't be too concerned. I like the car just fine, and frankly, it never gets down below 2500 while driving. It was a painful exercise to let it get down to 1500 in 4th.
02-02-2009, 03:56 PM
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are you having issues? can you link to the other thread?
Originally Posted by ADD' post='783554' date='Feb 2 2009, 04:54 PM
I ran it up from 1500-1800 up to 4500+.
Back down to 3000, floored it again, where I found that it is more responsive.
Back down to 1800, floored again, and it accelerated more slowly, but nothing I would consider out of the ordinary for any manual tranny in 4th at 1800 being floored. Ran it back up to 4500 or so.
The car feels more responsive in the 3000 and up range, but it feels just like it is in the sweet spot of the power band. Run it up to 3500, let off the gas, and get back on it, and it does feel quicker. I thought that was just the power band, not the turbos.
In any case, I shouldn't be too concerned. I like the car just fine, and frankly, it never gets down below 2500 while driving. It was a painful exercise to let it get down to 1500 in 4th.
Back down to 3000, floored it again, where I found that it is more responsive.
Back down to 1800, floored again, and it accelerated more slowly, but nothing I would consider out of the ordinary for any manual tranny in 4th at 1800 being floored. Ran it back up to 4500 or so.
The car feels more responsive in the 3000 and up range, but it feels just like it is in the sweet spot of the power band. Run it up to 3500, let off the gas, and get back on it, and it does feel quicker. I thought that was just the power band, not the turbos.
In any case, I shouldn't be too concerned. I like the car just fine, and frankly, it never gets down below 2500 while driving. It was a painful exercise to let it get down to 1500 in 4th.
02-03-2009, 06:52 AM
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My Ride: 2010 VW Passat Wagon 2.0l Tsi
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Lost to HPFP issues:
08 535i sport pkg
Lost to Dreaded E61 Sun roof leaks:
07 E61 530Xi
Does it feel like there is a power hesitation for a second ant then it spools up? This would be lag.
If your car is a 06/08 production car, I don't think you qualify for the DME 32.1 software. That is the way that the newer cars will run , at lease that what is being said. I'd Doubt you be able to find one but try driving a earlier production 535i with the old software. You'll feel the difference. It may be easier to do that with a E90 than a E60 due to the number of cars around.
The lag is the same way on the SAT's, Step, and 6sp's... it's just easier to see with the paddle shifters or the 6sp since you can hold the gear a bit easier. I can point you in the direction of a bunch of people that can give you a better explanation of it , if you like.
If your car is a 06/08 production car, I don't think you qualify for the DME 32.1 software. That is the way that the newer cars will run , at lease that what is being said. I'd Doubt you be able to find one but try driving a earlier production 535i with the old software. You'll feel the difference. It may be easier to do that with a E90 than a E60 due to the number of cars around.
The lag is the same way on the SAT's, Step, and 6sp's... it's just easier to see with the paddle shifters or the 6sp since you can hold the gear a bit easier. I can point you in the direction of a bunch of people that can give you a better explanation of it , if you like.
02-03-2009, 07:19 AM
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To me, it doesn't feel like the turbos spooling up, but then again, I've never owned a TT car before.
It seems to accelerate smoothly, not a burst of power at a higher rpm range.
The car does feel more responsive if you let off the gas at 3500 and then get back on it, but wouldn't any car?
Feel free to quote or refer me to others that you referenced.
Thanks!
It seems to accelerate smoothly, not a burst of power at a higher rpm range.
The car does feel more responsive if you let off the gas at 3500 and then get back on it, but wouldn't any car?
Feel free to quote or refer me to others that you referenced.
Thanks!
02-03-2009, 01:25 PM
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My Ride: 2010 VW Passat Wagon 2.0l Tsi
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Lost to HPFP issues:
08 535i sport pkg
Lost to Dreaded E61 Sun roof leaks:
07 E61 530Xi
Originally Posted by ADD' post='784080' date='Feb 3 2009, 10:19 AM
To me, it doesn't feel like the turbos spooling up, but then again, I've never owned a TT car before.
It seems to accelerate smoothly, not a burst of power at a higher rpm range.
The car does feel more responsive if you let off the gas at 3500 and then get back on it, but wouldn't any car?
Feel free to quote or refer me to others that you referenced.
Thanks!
It seems to accelerate smoothly, not a burst of power at a higher rpm range.
The car does feel more responsive if you let off the gas at 3500 and then get back on it, but wouldn't any car?
Feel free to quote or refer me to others that you referenced.
Thanks!
The first place to start is the thread in my sig... warning it is crazy long 150+ pages...
Here is another one on how the N54 works
http://www.e90post.com/forums/showthread.php?t=38856
They are good places to start.
The N54 turbos originally did not power up at High Rpm... the boost came on down low to help the motors low end power. Don't get me wrong they are still putting out power up high , but the the 530/28/25's do that with out the turbos.
If you have had a HPFP failure you know ( god forbid if you have I'm dealing with that now) , where most of the boost comes in... Down low, cause the cars drive like a Integra Type R then there is no boost, all upper end hp.
02-03-2009, 01:32 PM
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Originally Posted by bigbadbull' post='784340' date='Feb 3 2009, 02:25 PM
The first place to start is the thread in my sig... warning it is crazy long 150+ pages...
Here is another one on how the N54 works
http://www.e90post.com/forums/showthread.php?t=38856
Here is another one on how the N54 works
http://www.e90post.com/forums/showthread.php?t=38856
02-03-2009, 02:06 PM
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My Ride: 2008 535i: June 6th start build, complete June 17th, at NY Port July 5th, at dealer July 10th, took delivery Friday July 13- Plantimum Bronze/Natural Brown Leather/Light Poplar, Sport Package, Sport Auto, Active Steering, Premium Package, CWP & PDC. Dinan Performance Software 384hp & 421 ft/lbs.
If you bring an M5 down to 1500 rpm and then floor it, it will build power more slowly than if you started at 3000 rpm. Turbo lag is obvious, its like watching a badly dubbed kung-fu movie where the voice track lags the mouth movements.
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