I love my car. (0-60) - Page 5 - PeachParts Mercedes-Benz Forum

Brian Carlton · #61 05-12-2008, 09:30 AM

Quote:

Originally Posted by KarTek

OK, I realize you're correct now that I re-think it... Speed is acceleration over time regardless of weight... Oops.

Granted, at least two runs in opposite directions in any case make for the most accurate results. I still think the G-Tech will compensate for hills. When going up hill, the G-tech's percieved acceleration is greater because of being tilted rearward even though in reality the car is moving slower. The G-Tech will "think" you're going 60 when you're really going 55 or whatever so the time is lower.

Going down hill, the G-Tech's percieved acceleration is lower since it's tilted forward and it will continue to count time even when your speedometer is over 60.

Now I know this is not the case if you're stopped on a hill and you zero the unit out while the vehicle is tilted. It will only compensate it you start on the level and encounter any hill during the run.

I'll stick mine on later this evening and try it out to see what it does. I don't mind being wrong, I just like to understand why...

The unit definitely needs to be level for the accelerometer to work properly. The question is how much error you get from a 5 degree mounting error. My guess is that the mounting error would result in a display error that would be the cosine of 5 degrees..........nearly negligible. However, the change in acceleration rate for a 5 degree grade would be significant.

Therefore, I conclude that the unit cannot effectively compensate for hills.

But, I'd like to see your test results.

Hatterasguy · #62 05-12-2008, 01:29 PM

Quote:

Originally Posted by Ara T.

Sometimes I think there are more 0-60 threads in the MB diesel forum than you'd find in say, a Mustang forum

Its like the short guy who is always picking fights. We are compensating!

captainmonk · #63 05-12-2008, 01:37 PM

being 6' 5" even an old 6' 5" is better then 5' 6"

KarTek · #64 05-12-2008, 07:46 PM

OK, here's the results of my little 0-60 exercise...

Flat road:

8.61
7.17 (fluke?)
8.82
8.91

Moderate hill:

Up - 8.97
Down - 9.02

Steep hill:

Up - 8.52
Down - 8.59

All the numbers are pretty believable. The G-Tech will allow up to a .02g error and still allow the run so this accounts for some of the deviation. I didn't have time to set everything up perfectly for every run because cars kept coming up behind me and I couldn't relax and find the perfect spot to start each time. I'd like to try it again with someone else helping me with setup and possibly doing a video of each run so I could be even more consistant.

One thing I found interesting was that the times were slightly slower going down hill. Another reason I'd like to have a video is to compare the results of the G-Tech to the speed on the speedometer when it registers the 0-60 run complete.

Brian Carlton · #65 05-12-2008, 07:55 PM

Quote:

Originally Posted by KarTek

OK, here's the results of my little 0-60 exercise...

Flat road:

8.61
7.17 (fluke?)
8.82
8.91

Moderate hill:

Up - 8.97
Down - 9.02

Steep hill:

Up - 8.52
Down - 8.59

All the numbers are pretty believable. The G-Tech will allow up to a .02g error and still allow the run so this accounts for some of the deviation. I didn't have time to set everything up perfectly for every run because cars kept coming up behind me and I couldn't relax and find the perfect spot to start each run. I'd like to try it again with someone else helping me with setup and possibly doing a video of each run so I could be even more consistant.

One thing I found interesting was that the times were slightly slower going down hill. Another reason I'd like to have a video is to compare the results of the G-Tech to the speed on the speedometer when it registers the 0-60 run complete.

Now, that is positively amazing. Uphill.........downhill...........doesn't make any difference to the 0-60 times...........would never have believed it.

Thanks for doing the tests.