znod

Edit: I have abandoned this thread for this one. The old thread has beome dated, etc. Still, it may contain some info of interest, although the times and other data posted are out of date, have been revised, etc.

Edit: Duh, V-Tech = G-Tech.

Hi Friends:

I received my new GTech yesterday--the day I had my software reinstalled, etc. I set it up hurriedly this morning just to try it out on a 0 - 60 run. I am not going to tell you the general results because, whether really fast or really slow, they are not necessarily comparable to car mag or manufacturer times? And, who knows how they might compare to other G meters? I did talk to GTech and they indicated that it was not a good idea to try to compare G-Tech times/speeds with those of mags and manufacturers for a variety of reasons. To see how my car performs in the real-world, check out the "Kills" thread in "The Competition" forum.

I intend to post differences that might be attributable to procedures. Today, I did two quick 0 - 60 runs--the first in DS letting the Step do everything (starting in M1 of course) and the second turning DSC and DTS off and holding forward on the lever until 60 was reached (again starting in M1, of course). "Turning off" and "holding forward" produced a .06 difference in 0 - 60. I have no idea if the difference is "real," but I get the feeling that "holding forward" provides slightly faster shifts. I had no wheel spin so I assume "turning off" had no effect, but I am not sure. And, of course, I have not yet experimented with manual shifting. To check out some of the shifting-related issues, go here1 and here2.

I will be obtaining more results over time, of course, but I won't be in a big hurry to do so. I'll update this thread when I get additional info.

tomwid

The G-tech is pretty accurate. This guy in a Rentech SL600 used it and compared it to a drag run, which was pretty much the same results.

Let me guess, mid to high 13s 1/4 mile?

my530i

It should be 15s+

znod

At most?

znod

Hi tomwid. How's Tallahassee? We lived there in 1971-1973. I haven't done the 1/4, but I'm still not going to tell.

At most?
[/quote]
I managed to get a few more 0 to 60s in after looking at a HP/torque graph (not produced using optimal procedures). Having looked at the graph, I tried shifting manually at about 5,500 RPMs and right before the car shifted automatically--about 6,100 RPMs. Shifting at 6,100 was, as expected faster, but not that much faster. Shifting at 6,100 produced my best results to date except for an odd result that I have to try to duplicate/deal with. Shifting manually at 6,100 (with DSC and DTS off then and from now on) produced a .2 second faster run than my first one--with DS/auto shifting/DSC-DTS on. The result that I need to check into is that I let the car shift itself in D, and I got a savings of an additional .1--about .3 better than my first attempt. I am going to keep trying so I can work things out systematically. Eventually, I'll find a place to do a 1/4, but its hard to find a safe perfectly flat straight line.

tomwid

It's grown A LOT since 1973. I wasn't even born yet.

It's still a college town! GO NOLES!

znod

It's grown A LOT since 1973. I wasn't even born yet.

It's still a college town! GO NOLES!
[/quote]Yep, and way to go Seminoles for standing up to the NCAA or the match makers-- or whoever it was. I keep wondering if Oklahoma State will be "allowed" to keep calling themselves Cowboys. Cowboys could take offense. ~{;^} Lunacy runs rampant.

znod

545i Test Info

I am almost done testing before the installation of my Dinan intake. I have decided to share my results to date, including zero to sixty times, with you since I now can make some sense of them. I have done, maybe, ten zero to sixty runs. I have no intention of beating my car to death trying to get the fastest possible run.

I have done no quarter miles because I believe I can learn what I want to learn with zero to sixties, and it is very difficulty to find a flat 1/4 mile without going to more trouble than it is worth--including going to a dragstrip. The main point of using a G-meter, IMO, is finding "the" optimal technique.

My runs have fallen into the range of 5.43 sec. to about almost 6 sec. The best technique with the Step is to put the tranny into M1 and then let the Step shift itself--although starting in M1 may not really matter. I think that the reason it is optimal to let the tranny shift itself is because one must shift manually a bit too soon to beat the tranny to it, and I think the tranny shifts at least as fast by itself as it would with manual gear changes. Some of these conclusions might change with tranny programming.

I know of only one other who has tried a G-meter--realtyman (B&B exhaust, lighter wheels and tires, but no throttle body). He reported a best of 5.35 with his SMG not using the acceleration assistant. He uses the Escort GT2 meter, while I use, as mentioned, I use the GTech Pro SS meter.

I should mention that I did not not alter my normal tire pressures (30 psi rear), and did not use brake torquing. My times likely would improve if I lowered my pressures or used brake torquing. But, I am not going to go there. I am interested in getting the most out of my car the way it is set up for street use (no dragstrips for me). And, I would not use brake torquing no matter what the improvement because I don't want to hurt my car. Besides, I have had a traction problem since most of my testing has been done since colder weather set in. Indeed, I know there is "more" in my car if I could get adequate traction.

I can get times similar to 2 of the recent mag tests--5.4 to 5. But. despite my mods, I can't haven't been able to get times like the likely car-mag outlier of 5.2. In this regard, I think the 5.2 time is bogus. Below is what the big 3 US mag's tests yield:

BMW 545i--Manual C&D 5/04 5.5 14.1 103
BMW 545i--Step R&T 6/05 5.2 13.7 104.0
BMW 545i--Step MT 8/04 5.4 13.7 102.1
BMW 545i--Step MT11/05 5.5 13.8 102.8
(BMW claims 0 to 60 of 5.8 for the Step--which should be the average of a number of runs--not a best time as reported by the car mags.)

The 5.2 is highly suspicious to me because one of the other tests yields the same 1/4 mile time but a .2 sec slower 0 to 60. And, the Steptronic test yielding 0 to 60 of 5.5 yields a 1/4 mile time that is only .1 sec. slower than the test yielding the 5.2 0 to 60. Some of this reasoning gets fuzzier since the manual 545i gets a typical 5.5 0 to 60, but gets only 14.1 in the quarter. Go figure. Next, the 5.2 time is a full .6 sec. faster than BMW's claimed time--which seems like too much of a difference.

I know my car has more in it, but, given the cooler/colder weather pretty much since I started testing, I have had traction problems--which I have not been able to overcome satisfactorily. I think I have learned something if one wants max straight-line performance especially in cooler weather--stick with 18" wheels and get drag radials for in town, no rain, no snow, and no ice driving. BFG has them in the stock 275/35-18 size. I may have to get a third set of wheels tires. The 18" wheels (some model of BBS) would be even lighter, and it would be break-even on tire weight using the BFG's on the rear. The point of drag radials is not to beat on the car. Rather, it is to ensure that one is not stymied by loss of traction when wanting to go fast in a straight line.

Incidentally, if I did not make it clear earlier, DSC and DTC are devastating to acceleration from a stand still (even with DSC off/limited). Unfortunately, one can't turn DTC off and leave DSC on--as one can on my Z06. Thus, both have to be turned off for good acceleration at least from a stand still.

Z06 Test Info

I bought BFG drag radials for my Z06 because of time-devastating wheel spin in both 1st and 2nd gears. My safely-go-fast-in-a-straight-line-on-the-street procedure is to minimize wheel spin--which can be accomplished with new street tires just as well as with drag radials. I am not saying that my procedure is the fastest; it's just the one I prefer for consistency, to maximize tread life, for safety, and to reduce auto wear and tear. I am positive that one could launch at 4k RPM or so on the street, with good tires, and go faster than I can using my approach--assuming a good launch.

I used my GTech today for one zero to 60 run in my Z06. My result was 4.24 sec.--which I think I can improve on. I did not rev my engine at all, had almost zero wheel spin, and shifted very quickly to second without powershifting. I have some auto mags containing tests for 2002 to 2004 Z06's--which for all practical purposes are identical cars. Below are the mag times/speeds to 60 and in the 1/4. I did not include the results of one Car and Driver test since they were such outliers (crummy driver?). The magazines, of course, use much more aggressive launch and possibly shift procedures than I do.

C5 Z06 C&D 2/02 4.37 12.77 113.65
C5 Z06 MT 2/02 4.07 12.48 114.90
C5 Z06 MT 6/04 4.20 12.40 117.00
C5 Z06 MT 11/02 4.29 12.44 116.54
C5 Z06 MT 6/03 4.60 12.85 114.36
C5 Z06 R&T ?/02 4.30 12.70 112.10
C5 Z06 R&T 5/03 4.50 12.80 113.50

The 0 to 60 time for the MT 2/02 test is highly suspect since two other tests yielded better 1/4 mile times and 0 to 60 results similar to my VTech time.

znod

Above post updated.

markt540i

I am almost done testing before the installation of my Dinan intake. I have decided to share my results to date, including zero to sixty times, with you since I now can make some sense of them. I have done, maybe, ten zero to sixty runs. I have no intention of beating my car to death trying to get the fastest possible run.

I have done no quarter miles because I believe I can learn what I want to learn with zero to sixties, and it is very difficulty to find a flat 1/4 mile without going to more trouble than it is worth--including going to a dragstrip. The main point of using a G-meter, IMO, is finding "the" optimal technique.

My runs have fallen into the range of 5.55 sec. to about almost 6 sec. My best was on a 60 degree morning. I'll try one more time on a 40 degree morning if possible before my intake arrives. For me, the best technique with the Step is to put the tranny into M1 and then let the Step shift itself. Interestingly, I had a low 5.7 time with the tranny in D. I think that the reason it is optimal to let the tranny shift itself is because one must shift a bit too soon to beat the tranny to it, and I think the tranny shifts at least as fast by itself as it would with manual gear changes. Some of these conclusions might change with tranny programming.

I know of only one other who has tried a G-meter--realtyman (B&B exhaust, lighter wheels and tires, but no throttle body). As, I recall, he reported a best of 5.52 with his SMG not using the acceleration assistant. I am not sure what brand of G-Meter realtyman has.

I should mention that I did not play with my tire pressures, and did not use torque braking. It is possible that my times would improve if I changed my pressures and used mild brake-torquing. But, I am not going to go there. I am interested in getting the most out of my car the way it is set up for street use (no dragstrips for me). And, I would not use brake torquing no matter what the improvement.

Despite my mods, I can't get times like those in the car mags (5.4 to 5.5 with an outlier of 5.2), but I am close and think that is to be expected. also, the car mags probably abuse the Step with serious brake torguqing.

My best times are about .25 better than BMW's published value of 5.8 for the Step. I would be happy if my mods made a .25 difference (although I really like to get .3). After all, they look very good and sound very good too regardless of the performance enhancement. And, I expect the package to come together with the addition of the Dinan intake. After the intake is installed, I'll do a few more runs and then use the G-tech only on my Z06 (unless I get programming)--after getting some drag radials (being shipped). I'll report back at least one more time. It is cool now, and I have zero traction in the Z06--even though can and my GY SC's have only about 10K miles.
[/quote]

Great report. I look forward to what, if any, improvement you get with your intake installation. The 5.2 time you reference includes a 1 foot roll out, which the magazine notes takes the typical car about .3 seconds, so their 5.2 would about equal your 5.5 starting at a standstill.