W211 AMG Discuss the W211 AMG's such as the E55 and the E63
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g-tech pro question

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Old 09-23-2006, 01:07 PM
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'07 e63
g-tech pro question

Has anyone used this accelerometer with their e55 or e63? I'm considering getting one to give myself some personal insight into what this thing, e63, will do 0-60, 1/4. My questions is : Are they accurate? and What have others recorded 0-60, 1/4 on their AMG model, 63 or 55? Also, please state if you have modded the car.

Thanks a bunch.
DW

Sidenote: If I hadn't come across supposed HP issue regarding E63's, I would have never known. Coming from an '03 e46 M3 and a '02 911, I know what a fairly quick car fells like. My, never been calibrated, as$ dyno says my e63 is considerably faster. I too have contacted MB NA corporate regarding rumors... Waiting for a reply.
Old 09-23-2006, 01:33 PM
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SL 65 AMG and E63s AMG
Originally Posted by pilot e63
Has anyone used this accelerometer with their e55 or e63? I'm considering getting one to give myself some personal insight into what this thing, e63, will do 0-60, 1/4. My questions is : Are they accurate? and What have others recorded 0-60, 1/4 on their AMG model, 63 or 55? Also, please state if you have modded the car.

Thanks a bunch.
DW

Sidenote: If I hadn't come across supposed HP issue regarding E63's, I would have never known. Coming from an '03 e46 M3 and a '02 911, I know what a fairly quick car fells like. My, never been calibrated, as$ dyno says my e63 is considerably faster. I too have contacted MB NA corporate regarding rumors... Waiting for a reply.
I don't know about the g tech pro but I've been using Vericom 2000 which is a predecessor of the smaller units for years. I think you have to take the info with a grain of salt and use it for practice and relative mod assessment.

My Vericom according to my GNX drag buddy is usually +/-.2sec in the quarter. Not something you want to hang your hat on but gets you in the ball park. V2000 device measures down to .001g and .001sec. I remember that it was way more expensive than I wanted to spend but needed it to assess real changes in setup in my Vette without going to the track.

FWIW I looked at my calculated torque numbers from my Vette with NOS before I added my Lingenfelter intake and they are exactly the same as the E55. Obviously because the E55 is 1000 pounds heavier it makes significantly more HP.

I've been playing with the V2000 lately but have not had a chance to find a straight deserted highway to run the quarter in. Hopefully I'll be able to do this soon. On the street with a passenger I'm running 0-60 times from 4.3 to 4.7 with a bad launch. Getting out the blocks is critical for good times. It's very tricky with an E55. I think that I can improve on those times.

Last edited by Vetluver; 09-23-2006 at 01:37 PM.
Old 09-23-2006, 06:05 PM
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'07 e63
thanks vet luver for the info
BR,
Pilot e63
Old 09-23-2006, 06:40 PM
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As the other poster said, it will get you in the ballpark.

The GTech pro seems to run about 1-2 tenths and 2-3 MPH fast. The results are repeatable, however.
Old 09-23-2006, 11:54 PM
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The newer style G-Tech pros are actually very accurate. THere was an article in either Car and Driver or Road and Track about a year ago which compared all these devices all the way to their own VBOX which is I think more than 10K. The G-tech pro was dead on in the 0-60, and 1/4 time. The Et was about 1-2mph faster than the what the track was showing. But they explained that the G-tech is actually more accurate because the speed shown by the track is a number averaged during the last portion of the 1/4 run, where with the G-tech it is your actual speed at the moment you cross the 1/4 mile mark. I wish I had saved that damn article. Overall, I bought one after I read the article.
Old 09-24-2006, 02:12 AM
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Ok...I have to ask: How much are they?
Old 09-24-2006, 02:27 AM
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With Gtech you have to calibrate it for every car you want to test and if you don't enter the correct info ( for example weight of the car ), the reading may not be so accurate. U might want to check out the Driftbox, which uses GPS and does not require calibration. I only found out about it after I got the Gtech.
Old 09-24-2006, 10:48 AM
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Originally Posted by Jspeed
With Gtech you have to calibrate it for every car you want to test and if you don't enter the correct info ( for example weight of the car ), the reading may not be so accurate. U might want to check out the Driftbox, which uses GPS and does not require calibration. I only found out about it after I got the Gtech.
The information above is misleading. The only thing that will be off if u dont input the weight of the car is the calclulated horsepower. The G-tech will take your 0-60 or 1/4 time and devided by the weight of the car and give you a real world of how much power you are putting to the ground. This number is much lower than even a dyno rwhp number, because its also including wind resitance,etc. Its only useful when getting a baseline number and comparing it if u do upgrades. But you can see the improvements in your 0-60 and 1/4times anyways.

The newer G-techs automatically self calibrate themsevles on the 3-d axis everytime you make a run. The only thing u need to do is to set calibrate your rpms if you want to look at your 1/4 run and see your rpm shift points, but you don't even need to calibrate your RPMs if u just want to do a 0-60 and 1/4 time. The g-tech doesn't care what vehicle its put in. If it goes from standstill to 60 in 4.0 seconds thats what it will show, whether its in a mustang or a mercedes.
Old 09-24-2006, 04:45 PM
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Originally Posted by saman6164
The information above is misleading. The only thing that will be off if u dont input the weight of the car is the calclulated horsepower. The G-tech will take your 0-60 or 1/4 time and devided by the weight of the car and give you a real world of how much power you are putting to the ground. This number is much lower than even a dyno rwhp number, because its also including wind resitance,etc. Its only useful when getting a baseline number and comparing it if u do upgrades. But you can see the improvements in your 0-60 and 1/4times anyways.

The newer G-techs automatically self calibrate themsevles on the 3-d axis everytime you make a run. The only thing u need to do is to set calibrate your rpms if you want to look at your 1/4 run and see your rpm shift points, but you don't even need to calibrate your RPMs if u just want to do a 0-60 and 1/4 time. The g-tech doesn't care what vehicle its put in. If it goes from standstill to 60 in 4.0 seconds thats what it will show, whether its in a mustang or a mercedes.
Actually, you do need to calibrate the Gtech to your specific car if you want dead-on accurate results. I do agree it is extremely repeatable, and extremely accurate, if it is set up properly. I've probably done 50 quarter mile runs with my Gtech RR.

There is a number called the 'pitch factor' (PF) that takes into account 'squat' on acceleration, and needs to be set based on how stiff your suspension is. The PF is set to 2.0 at the factory, based on a run in a 2003 BMW M3. If your suspension is softer than the M3, you may need a higher pitch factor, if it is sprung more stiffly, you may need a lower number. To get the correct pitch factor for your car, you need to take the car to a dragstrip, and use the Gtech on a run. There is a formula in the manual to calculate the proper PF based on the actual run trapspeed, and the Gtech indicated speed.

For my M5, I used the original PF and did a number of runs, then I installed aftermarket springs. Using the same PF, my trapspeed was 2 mph lower because of the stiffer springs. I've since gone to the strip and calibrated the Gtech with a PF of .7. It is now accurate to the dragstrip numbers to within better than 1 percent. Here is a sample graph of a run I just did:

Old 09-28-2006, 11:22 PM
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04 E55
What is the correct weight factor for an 04 E55 ?
Old 09-29-2006, 09:11 AM
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Originally Posted by vader
What is the correct weight factor for an 04 E55 ?
I think you mean Pitch Factor. If you use the original PF of 2.0 the unit is shipped with, you will be in the ballpark. The stiffer your suspension is, the lower the PF should be. The 2.0 was set using a 2003 BMW M3. The lower the PF is set to, the higher your speeds will be.

The best way to calibrate the Gtech is to take it to the dragstrip. You set your PF to 0 and do a run. Then you plug the actual (timeslip) trapspeed, and the Gtech indicated trapspeed into a formula (in the manual), and calculate your exact PF for that car. I did that, and I can now do 1/4 mile runs at my 'private' dragstrip...
Old 09-29-2006, 10:16 AM
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04 E55
Sorry for my wording...I did mean the weight of the vehicle !!! 2 tons of fun doesn't work !!!
Old 09-30-2006, 12:02 PM
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04 E55
I input 4150 for the weight...I weigh 165 lbs. My 0-60 runs were 4.24 and the second was 4.6. Second run I came out of the hole poorly...does the correct weight of the car factor into the 0-60 ? Couldn't quite get a 1/4 mile due to safety. the HP was at 390 on the first 0-60 at 6060 rpm's...this thing is cool but how accurate is the 0-60? I had it lowered and in S2 and let it shift itself in Sport.
Old 09-30-2006, 12:12 PM
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Originally Posted by vader
I input 4150 for the weight...I weigh 165 lbs. My 0-60 runs were 4.24 and the second was 4.6. Second run I came out of the hole poorly...does the correct weight of the car factor into the 0-60 ? Couldn't quite get a 1/4 mile due to safety. the HP was at 390 on the first 0-60 at 6060 rpm's...this thing is cool but how accurate is the 0-60? I had it lowered and in S2 and let it shift itself in Sport.

The car weight won't affect the acceleration times, it is used in the HP calculations. I can't get the *&%^$ rpm calibration to work properly, so the HP and any other calculations that use rpm don't work.

The acceleration is really accurate though. I calibrated it at the dragstrip, and for this unit, and my car (lowered H&R springs and spacers, BBS 20" wheels) the correct PF is .7. If you can do just one dragstrip run and calibrate it, you can get really good accuracy. I'll guess I'm within a few tenths of an mph on trapspeeds.
Old 09-30-2006, 12:20 PM
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04 E55
The RPM cali was a pain but when it asked for 4000 i set it down to 3000 on the high side and calibrated it there since it won't go to 4k in Park. Then there is another screen that chooses the best rpm calibration which brought it in perfect after fiddling for a while. I think the weight I put in is a bit on the light side.... I must have missed the 1/4 mark by a couple hundred feet.
Old 10-12-2006, 01:48 AM
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Originally Posted by saman6164
The newer style G-Tech pros are actually very accurate. THere was an article in either Car and Driver or Road and Track about a year ago which compared all these devices all the way to their own VBOX which is I think more than 10K. The G-tech pro was dead on in the 0-60, and 1/4 time. The Et was about 1-2mph faster than the what the track was showing. But they explained that the G-tech is actually more accurate because the speed shown by the track is a number averaged during the last portion of the 1/4 run, where with the G-tech it is your actual speed at the moment you cross the 1/4 mile mark. I wish I had saved that damn article. Overall, I bought one after I read the article.
http://www.caranddriver.com/features...ters-work.html

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