Acceleration, shift points, and fuel economy

chewie · 05-28-2009, 11:55 PM

Hi guys,

I used the search function but didn't really see this addressed directly. I just got my 2003 2.5 z4r about 3 weeks ago. It's my first car, and my first extensive experience with a manual gearbox. I was always under the impression that slower acceleration produced better fuel economy, but I've recently heard otherwise. I'm just wondering if anyone has any experience with what RPM shiftpoints and acceleration rates produce the best fuel economy? I don't have a computer on my car. I short-shift the heck out of my 5-speed. I try to never go over 2000 RPM unless I'm on the highway, and I'm usually in 5th by the time I hit 50km/h (35mph). Is this good or bad?

While we're at it, is there any way to smooth out the shifts from 1st-2nd and 2nd-3rd? Just ride the clutch a little more?

Thanks!

bkz4mc · 05-29-2009, 01:02 AM

Quote:

Originally Posted by chewie

Hi guys,

I used the search function but didn't really see this addressed directly. I just got my 2003 2.5 z4r about 3 weeks ago. It's my first car, and my first extensive experience with a manual gearbox. I was always under the impression that slower acceleration produced better fuel economy, but I've recently heard otherwise. I'm just wondering if anyone has any experience with what RPM shiftpoints and acceleration rates produce the best fuel economy? I don't have a computer on my car. I short-shift the heck out of my 5-speed. I try to never go over 2000 RPM unless I'm on the highway, and I'm usually in 5th by the time I hit 50km/h (35mph). Is this good or bad?

While we're at it, is there any way to smooth out the shifts from 1st-2nd and 2nd-3rd? Just ride the clutch a little more?

Thanks!

Dude... not trying to be a dick, but why did you buy a sports car if you want to drive it like a granny ? Come on man... enjoy the car you just bought ! It'll take a lot more abuse than you'll ever want to give it... don't worry so much.

As far as making shifts smoother, research the CDV Valve delete mod.

rc'Z · 05-29-2009, 05:38 AM

Welcome to the Forum! Every time you take your foot off the gas and put it back on the gas again, like every time you shift gears, you are actually shooting a little more gas in the engine. If you notice auto's usually get bette miliage in town than sticks do. The less you shift to get to speed the better you mpg will be. For instance, I usually use 1st to 4-5k, then go to second, run it up to about 45 it that is the speed limit, because it's fun, and then go to 6th. Yes, skipping 3, 4, 5. If speed limit is 35, I do 1, 2, 5. Driving this way gives me 25 around town while having fun. My car runs about 36 on the highway. Of course stop light drag races and curvy road grand prixs are another matter. But even with a few of those the above mpg is good. I didn't buy the car for the mpg but was pleased to see what it does. Drive your car the way you want to. Not everybody's enjoyment or finances are the same. Be your own person.

banger · 05-29-2009, 10:35 AM

I really don't know where the shift points are...

I drive by "ear". The sound tells me when to shift.

Understand though, I have been driving sticks for MANY years.

chewie · 05-29-2009, 03:56 PM

Thanks for the replies so far. Yes, I understand I have a sports car, but I just graduated from University and I dumped my entire life savings to buy this car and as of now I only work part time. This car is my daily driver, so I need to drive conservatively until I have some more financial stability. Even after I have that stability, I'll still want to get the best MPG as I can since it's the smart thing to do. For the record, even driving "like a granny", I am thouroughly enjoying my car. I'm a little more into "show" vs. "go" at this point, anyway.

I've only filled up once so far, but it looks like I'm getting around 9.5l/100km with 90%city/10%highway. I think that's around 23-25 MPG or so, but I could be wrong.

I'll look into CDV delete, thanks. It's weird though...sometimes 1-2 and 2-3 is really smooth (like today), and sometimes it's really jerky, but I don't think I'm changing my driving style much. Today I did accelerate a little harder, though, so maybe that helps a bit.

mpower03 · 05-29-2009, 04:38 PM

your timing is off causing the car to be jerky. You probably already past the engagement point when you let the clutch out before you gave it gas. Learn where your engagement point is and it will smooth out.

chewie · 05-29-2009, 06:00 PM

Hmm, yeah it could just be my skills or lack thereof. I know where the engagement point is, but I'm probably dumping the clutch since I'm pretty new.

I looked up info on the CDV. Could someone outline the pros/cons of doing a full delete vs. replacing it with a modified one?

BMW Maniac · 05-29-2009, 08:58 PM

You just graduated and dumped your entire life savings to buy this car......drive it like you stole it I say

mpower03 · 05-29-2009, 09:42 PM

just replace it with a modified one.

Matty C · 05-31-2009, 02:58 AM

Congrats on your first new car and you made a great choice in buying a BMW. I've never driven anything besides a manual gearbox and still had problems with my Z4 M being jerky. I purchased a modified CDV from Zweckhausen Racing. It has made all the difference in the world. Honestly for the money it was one of the best modes I believe could be made for adding to driving pleasure. As far as shift points go, you have to get a fell for your car. You know your preferred driving style and that will set where and when you shift. Good luck and have fun with your new toy!

z4dawg · 05-31-2009, 04:32 PM

what's the word on modified CDV on the warranty? I suppose it comes down to the judgement of your dealer right?

GP20 · 05-31-2009, 04:35 PM

Quote:

Originally Posted by z4dawg

what's the word on modified CDV on the warranty? I suppose it comes down to the judgement of your dealer right?

If something goes wrong with your transmission, the modified CDV won't help. All it takes is for the tech to drive a couple of blocks to know you have a modified CDV. You'd have to put your stock CDV back in place if you want to take the car to the dealer for transmission related issues. All the modified CDV does is when the tech is working on other issues unrelated to the transmssion and when the car's on a lift, the dealer doesn't just simply spot that your car is missing the CDV and void your transmission warranty right there.

caseysc · 05-31-2009, 07:11 PM

Upshift and downshift at 2500 RPM until you get the feel of the car.

I'm sorry to see that you "dumped" your life savings into a @#$%&* car! Yes, you are young and have time to recover from this...words fail me...mistake. Get your head together and focus on your future rather than a car that depreciates every minute you drive it. Where was your family when you made this decision?

Hawkeye · 05-31-2009, 09:28 PM

Quote:

Originally Posted by chewie

I dumped my entire life savings to buy this car and as of now I only work part time. ... I'll still want to get the best MPG as I can since it's the smart thing to do.

Wow, you contradicted yourself in a big way in one paragraph!!!

You dumped your life savings into a car without a stable income or job... yet you want to do "the smart thing".

I did about the same (except I had a stable job I guess) and I drive mine hard. It likes to be driven hard. You really don't need the CDV for smooth shifts, mine shifts smooth and I have not done a delete. You just need to take it to some higher RPMs. BTW, I race mine off the line and accelerate very fast a lot... and I get about 24-25 MPG consistenty with a lot of city driving so you're not doing yourself much good by granny-ing it.

veryhuman · 05-31-2009, 11:36 PM

Quote:

Originally Posted by chewie

Hi guys,

I used the search function but didn't really see this addressed directly. I just got my 2003 2.5 z4r about 3 weeks ago. It's my first car, and my first extensive experience with a manual gearbox. I was always under the impression that slower acceleration produced better fuel economy, but I've recently heard otherwise. I'm just wondering if anyone has any experience with what RPM shiftpoints and acceleration rates produce the best fuel economy? I don't have a computer on my car. I short-shift the heck out of my 5-speed. I try to never go over 2000 RPM unless I'm on the highway, and I'm usually in 5th by the time I hit 50km/h (35mph). Is this good or bad?

While we're at it, is there any way to smooth out the shifts from 1st-2nd and 2nd-3rd? Just ride the clutch a little more?

Thanks!

lol, 50km/h at 5th gear. I think you are doing harm to the transmission. I'm getting about 11L/100km, and my shift points are 3000 - 4000 RPM, I am into 5th gear around 110km/h

ZStig · 05-31-2009, 11:53 PM

1st gear I shift around 4500, 2nd around 4000, third around 3500 under normal acceleration. but I have shorter gears, and don't care about losing 1or 2 mpg

Matty C · 06-01-2009, 12:19 AM

Wow,
I wish that I saw 11L / 100km. I see 13.9L / 100km. I drive mine hard and it also see 155mph on the autobahn often. I don't think anyone purchases these cars for the mileage!

Hawkeye · 06-01-2009, 09:19 AM

Quote:

Originally Posted by Matty C

Wow,
I wish that I saw 11L / 100km. I see 13.9L / 100km. I drive mine hard and it also see 155mph on the autobahn often. I don't think anyone purchases these cars for the mileage!

He does have a 2.5i and not an M though... probably why such the difference in KmPG (MPG)..

quickfast · 06-01-2009, 11:39 AM

The marginal difference is insignificant....

DarkstarZero · 06-01-2009, 01:45 PM

Dude you just finished college so do the maths. Driving like a granny to get a few extra MPG, vs driving normal (how you really want to drive it to enjoy it), you're only going to save about $8 per tank. $8! In my last manual M3s I could drive like a granny and get 23-24mpg or drive normal and get 19-20mpg or drive flat out everywhere and get 13mpg. The $$ difference to fun ratio is too low.

Spend the extra money and enjoy it. Life is too short to worry about $8 a tank. If you want to justify it, skip lunch one day.

caseysc · 06-01-2009, 04:24 PM

Quote:

Originally Posted by DarkstarZero

Spend the extra money and enjoy it. Life is too short to worry about $8 a tank. If you want to justify it, skip lunch one day.

Or...skip lunch every day, stop offering to pay on a date, don't worry about replacing worn clothing, skip the Mom's and Father's day presents, cancel cable/satellite TV, stop buying new X-Box games and put off vacations until you have a FULL TIME JOB!

Sorry, my son was in a similiar situation and could not pull his head out of his ass without my guidance and body blows.

chewie · 06-01-2009, 05:15 PM

Wow, so much hate in this thread for no apparent reason. I just asked how to improve my MPG, that's all. Is there some rule that says I can't seek maximum MPG in my Z4? It was my decision, not my family's, but they supported me throughout. I bought a car that makes me happier than any other car I might've bought. Why would I spend thousands of dollars on something that I wouldn't be happy about?

I work close to 30 hours a week for the government (note, this is still considered part time), so it's not like I flip burgers in a mall. And I will be earning an entry level salary of over $54k, likely within 6 months if not the year.

Simple question warrants a simple answer. Thanks for those who provided it. To the others, I suggest you gather the relevant information in the future before making suggestions based on assumptions.

05-28-2009, 11:55 PM	#1
chewie Private 4 Rep 74 Posts Drives: 2003 Z4 2.5 Join Date: Apr 2009 Location: Vancouver, BC, Canada iTrader: (0)	Acceleration, shift points, and fuel economy Hi guys, I used the search function but didn't really see this addressed directly. I just got my 2003 2.5 z4r about 3 weeks ago. It's my first car, and my first extensive experience with a manual gearbox. I was always under the impression that slower acceleration produced better fuel economy, but I've recently heard otherwise. I'm just wondering if anyone has any experience with what RPM shiftpoints and acceleration rates produce the best fuel economy? I don't have a computer on my car. I short-shift the heck out of my 5-speed. I try to never go over 2000 RPM unless I'm on the highway, and I'm usually in 5th by the time I hit 50km/h (35mph). Is this good or bad? While we're at it, is there any way to smooth out the shifts from 1st-2nd and 2nd-3rd? Just ride the clutch a little more? Thanks!
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05-29-2009, 05:38 AM	#3
rc'Z Captain 13 Rep 821 Posts Drives: 2009 335i Convertible Join Date: Dec 2007 Location: Virginia iTrader: (0)	Welcome to the Forum! Every time you take your foot off the gas and put it back on the gas again, like every time you shift gears, you are actually shooting a little more gas in the engine. If you notice auto's usually get bette miliage in town than sticks do. The less you shift to get to speed the better you mpg will be. For instance, I usually use 1st to 4-5k, then go to second, run it up to about 45 it that is the speed limit, because it's fun, and then go to 6th. Yes, skipping 3, 4, 5. If speed limit is 35, I do 1, 2, 5. Driving this way gives me 25 around town while having fun. My car runs about 36 on the highway. Of course stop light drag races and curvy road grand prixs are another matter. But even with a few of those the above mpg is good. I didn't buy the car for the mpg but was pleased to see what it does. Drive your car the way you want to. Not everybody's enjoyment or finances are the same. Be your own person.
	Appreciate 0 Quote

05-29-2009, 10:35 AM	#4
banger New Member 0 Rep 20 Posts Drives: 2008 Si Roadie Join Date: Apr 2009 Location: occupied east coast iTrader: (0)	I really don't know where the shift points are... I drive by "ear". The sound tells me when to shift. Understand though, I have been driving sticks for MANY years.
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05-29-2009, 03:56 PM	#5
chewie Private 4 Rep 74 Posts Drives: 2003 Z4 2.5 Join Date: Apr 2009 Location: Vancouver, BC, Canada iTrader: (0)	Thanks for the replies so far. Yes, I understand I have a sports car, but I just graduated from University and I dumped my entire life savings to buy this car and as of now I only work part time. This car is my daily driver, so I need to drive conservatively until I have some more financial stability. Even after I have that stability, I'll still want to get the best MPG as I can since it's the smart thing to do. For the record, even driving "like a granny", I am thouroughly enjoying my car. I'm a little more into "show" vs. "go" at this point, anyway. I've only filled up once so far, but it looks like I'm getting around 9.5l/100km with 90%city/10%highway. I think that's around 23-25 MPG or so, but I could be wrong. I'll look into CDV delete, thanks. It's weird though...sometimes 1-2 and 2-3 is really smooth (like today), and sometimes it's really jerky, but I don't think I'm changing my driving style much. Today I did accelerate a little harder, though, so maybe that helps a bit.
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05-29-2009, 04:38 PM	#6
mpower03 Captain 39 Rep 962 Posts Drives: 08 z4 M Coupe Join Date: Sep 2008 Location: FL iTrader: (2)	your timing is off causing the car to be jerky. You probably already past the engagement point when you let the clutch out before you gave it gas. Learn where your engagement point is and it will smooth out. __________________
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05-29-2009, 06:00 PM	#7
chewie Private 4 Rep 74 Posts Drives: 2003 Z4 2.5 Join Date: Apr 2009 Location: Vancouver, BC, Canada iTrader: (0)	Hmm, yeah it could just be my skills or lack thereof. I know where the engagement point is, but I'm probably dumping the clutch since I'm pretty new. I looked up info on the CDV. Could someone outline the pros/cons of doing a full delete vs. replacing it with a modified one?
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05-29-2009, 08:58 PM	#8
BMW Maniac Lieutenant 22 Rep 428 Posts Drives: Former Z4M coupe owner Join Date: Jan 2009 Location: Orlando, FL iTrader: (1)	You just graduated and dumped your entire life savings to buy this car......drive it like you stole it I say __________________ 1997 /// M3 Coupe Arctic Silver CES STAGE IV (651rwhp/615rwtq) 1999 /// M3 Convertible Techno Violet
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05-29-2009, 09:42 PM	#9
mpower03 Captain 39 Rep 962 Posts Drives: 08 z4 M Coupe Join Date: Sep 2008 Location: FL iTrader: (2)	just replace it with a modified one. __________________
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05-31-2009, 02:58 AM	#10
Matty C First Lieutenant 20 Rep 324 Posts Drives: 2007 Z4 M Roadster, 2006 M3 Join Date: May 2009 Location: Bodensee iTrader: (0)	Congrats on your first new car and you made a great choice in buying a BMW. I've never driven anything besides a manual gearbox and still had problems with my Z4 M being jerky. I purchased a modified CDV from Zweckhausen Racing. It has made all the difference in the world. Honestly for the money it was one of the best modes I believe could be made for adding to driving pleasure. As far as shift points go, you have to get a fell for your car. You know your preferred driving style and that will set where and when you shift. Good luck and have fun with your new toy!
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05-31-2009, 04:32 PM	#11
z4dawg New Member 0 Rep 8 Posts Drives: Bright Red '06 3.0i Z4 Join Date: May 2009 Location: Atlanta/Athens, GA iTrader: (0)	what's the word on modified CDV on the warranty? I suppose it comes down to the judgement of your dealer right?
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05-31-2009, 07:11 PM	#13
caseysc Second Lieutenant 9 Rep 274 Posts Drives: 2010 128i Conv. Join Date: Jul 2007 Location: Aiken, SC iTrader: (0) Garage List 2005 Z4 2.5i [8.00]	Upshift and downshift at 2500 RPM until you get the feel of the car. I'm sorry to see that you "dumped" your life savings into a @#$%&* car! Yes, you are young and have time to recover from this...words fail me...mistake. Get your head together and focus on your future rather than a car that depreciates every minute you drive it. Where was your family when you made this decision?
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05-31-2009, 11:53 PM	#16
ZStig instagram 997turbotom 279 Rep 7,377 Posts Drives: Interlagos Z4MR Join Date: Jun 2008 Location: Delray Beach, FL iTrader: (4)	1st gear I shift around 4500, 2nd around 4000, third around 3500 under normal acceleration. but I have shorter gears, and don't care about losing 1or 2 mpg __________________
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06-01-2009, 12:19 AM	#17
Matty C First Lieutenant 20 Rep 324 Posts Drives: 2007 Z4 M Roadster, 2006 M3 Join Date: May 2009 Location: Bodensee iTrader: (0)	Wow, I wish that I saw 11L / 100km. I see 13.9L / 100km. I drive mine hard and it also see 155mph on the autobahn often. I don't think anyone purchases these cars for the mileage!
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06-01-2009, 11:39 AM	#19
quickfast Private First Class 7 Rep 160 Posts Drives: quickfast Join Date: Sep 2008 Location: Brooklyn iTrader: (0)	The marginal difference is insignificant....
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06-01-2009, 01:45 PM	#20
DarkstarZero Lieutenant Colonel 1014 Rep 1,721 Posts Drives: Daytona 95 M3, X7 M50, e92 M3, Join Date: Nov 2007 Location: Washington DC iTrader: (6)	Dude you just finished college so do the maths. Driving like a granny to get a few extra MPG, vs driving normal (how you really want to drive it to enjoy it), you're only going to save about $8 per tank. $8! In my last manual M3s I could drive like a granny and get 23-24mpg or drive normal and get 19-20mpg or drive flat out everywhere and get 13mpg. The $$ difference to fun ratio is too low. Spend the extra money and enjoy it. Life is too short to worry about $8 a tank. If you want to justify it, skip lunch one day. __________________ BMW CCA Track Instructor Join to win a M School Day at the Performance Center! Enter Referral ID: 420186
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06-01-2009, 05:15 PM	#22
chewie Private 4 Rep 74 Posts Drives: 2003 Z4 2.5 Join Date: Apr 2009 Location: Vancouver, BC, Canada iTrader: (0)	Wow, so much hate in this thread for no apparent reason. I just asked how to improve my MPG, that's all. Is there some rule that says I can't seek maximum MPG in my Z4? It was my decision, not my family's, but they supported me throughout. I bought a car that makes me happier than any other car I might've bought. Why would I spend thousands of dollars on something that I wouldn't be happy about? I work close to 30 hours a week for the government (note, this is still considered part time), so it's not like I flip burgers in a mall. And I will be earning an entry level salary of over $54k, likely within 6 months if not the year. Simple question warrants a simple answer. Thanks for those who provided it. To the others, I suggest you gather the relevant information in the future before making suggestions based on assumptions.
	Appreciate 0 Quote