0-60 results with a new GPS G-Tech meter ('97 840ci)

[Corellian Corve]

After doing some research on performance meters I ended up choosing the G-Tech SS GPS meter and it arrived tonight. Since the 840 has a freshly installed 3.64 rear diff in it, I was curious to see what my 0-60 times were (and play with my new gadget)

Now, I own a ton of cars - some modified, some stock. So I need to establish a consistent testing metric between cars, since I'd like to be *somewhat* scientific, and the more repeatable the test, the better to compare cars, and compare upgrades. I only have two good cars here at my home shop, so I ran both tonight for fun. One of course was the 840.

Fortunately I have a very nice, very quiet, very flat road near my house where I can safely do some runs without bothering anyone.

My test parameters are going to be the same for each car.

• Full tank of gas.
• Everything off (Radio, A/C, Lights, etc)
• Windows up, Sunroof closed
• Antennas down if possible.
• Trunk empty except for factory stuff (spare tire, etc)
• Track mileage and outside temperature

I'm going to do two runs, back-to-back, to average the time. I will also test with and without Sport mode (if applicable)

I'm going to keep records of any mods to the car, and I'm also trying to track down any official published 0-60 times so for my unmodified cars I can get a sense of trends on correction factor.

So with that, the results!

Mileage - 95K
Outside Temp - 66 deg.
Run 1 (sport mode) 6.65
Run 2 (no sport mode) 6.59
Avg. 0-60: 6.62

Now, I was pleased with that number. First, it appears to be quite an improvement over the published numbers I could find (anywhere from 7.3 - 7.5 factory stock). It also affirmed my butt-dyno which estimated at least 1/2 a second shaved off my original car. I *wish* I had owned this device before I made the diff change! But I've been thinking about an exhaust modification so I now I have a baseline which is why I bought the G-tech!

I also read an argument on the e38 forum about the difference between Sport and Normal shifting mode, with a member suggesting that S made the car more spirited for a road car, but did nothing for 0-60 times. In my test of 1 that appears true (S) mode was actually a tad slower, but the difference in time is well within the margin of error of the device itself.

Good news is that I have a bone stock e38 740i Msport, e39 M5, and e39 528 - all with sport modes, so I can gather more data for this test.

I'm going to pull up the graphs of the runs and play around more with the SW. But wanted to share the results.

[mikae31]

Nice. Its good you are able to do some real testing and we can see the actual improvement in numbers.

That acceleration time is good imrovement over stock. I wish someone could do the same with stock M70 with 4-speed auto with 3,91 lsd from e34 M5. I have purchased that M5 3,91 lsd diff but have been wondering is it worth the increased rpm and fuel consumption?

Your car has M62 engine, right? According to www.e31.net it should accelerate 0-62 in 7s.

[Hyper]

Sorry, on a couple of points...
On my "Up Before Six" project, I reported for the '97 840 an independently published number of 6.8 seconds.
Similar to you I did not think to measure bone stock.
However, my otherwise stock with 3.15 mod was clocked by Gtech at 6.6s (+/-).

{added: table from B46 project, 3.15 baseline in red}

[sid33]

Very cool. With a full tank of gas, that's almost an extra 150lb! I guess is would too much of a pain to ensure each car had X amount of fuel. Full tank is easiest. I know these aren't speed demons, but it's nice to see the numbers. Thanks.

[clubE31]

... haha.... an 850 (even csi) will never be fast from 0-60mph (just too heavy)..... a lot of diesels (audi, bmw) will beat you at the light !

Once it has some speed it is actually not a slow car, so 90-120kph or 50-100 kph or even 100-200 kph times would be far more interesting.

[Corellian Corve]

Yeah it's been fun. I've tested three of my cars so far. Tonight I did two runs with my 2000 740i M-sport. Same road, full tank, etc. Car is bone stock with 136K.

Found a MT article from '99 which reported 0-60 in 5.9sec.

My car ran an average 6.10 which seems well within the margin for age and mileage.

So feeling pretty good about the accuracy and repeatability of these results. I'm going to test some more stock cars and see how they stack up.

[mikae31]

I wonder why 8 is so slow? I mean even your 740 is noticeable quicker in your tests.. why is that. I dont think 8 is heavier than 740. Does that 2000 740i has better transmission or what explains the difference.

I have M70 850 and even manual e34 535 is pretty much the same in acceleration to 100km/h. What slightly bothers me is that 8 looks panther but is cow.

[Corellian Corve]

Well... the 7 series was faster from the factory, so no surprise it's faster in my tests.

The 8 and the 7 weights are actually pretty similar based on what I can see (8 shared a lot of platform from the e32 7 series)

The e38 7 has a better engine (M62TU), and the m-sport has more aggressive gears and a higher-stall torque converter.

Also the car is from 1997 and was always intended to be a GT car. 6-7 seconds in the 90's was no slouch, when the average sedan was 8-9 seconds, and a light-weight Mustang GT was a 6.5 - 7 second car.

So it's all relative - compared to today, it's slow. Compared to cars at the time, it was pretty damn quick.

[mikae31]

Yes its relative but i still dont think that eight was quick compared to cars at the time. 94 Mustang gt's acceleration is 6,1s.

Bmw should have done something to make eight series faster than seven series. A regular M70 850 should have done 0-62 second faster originally.

[XAlt]

Yes its relative but i still dont think that eight was quick compared to cars at the time. 94 Mustang gt's acceleration is 6,1s.

Bmw should have done something to make eight series faster than seven series. A regular M70 850 should have done 0-62 second faster originally.

Who cares, to the people it was marketed to, it's a cool looking 750iL that you're forced to drive. If they wanted to go faster, Alpina and Dinan was always around.

It had enough torque for a butt dyno and enough horsepower to get to 155, that's all it needed to do to send the venerable 560SEC to its grave.

[mikae31]

Who cares, to the people it was marketed to, it's a cool looking 750iL that you're forced to drive. If they wanted to go faster, Alpina and Dinan was always around.

It had enough torque for a butt dyno and enough horsepower to get to 155, that's all it needed to do to send the venerable 560SEC to its grave.

???

Standard 560sec did 0-62 in 6,6s and top speed 155...

[XAlt]

???

Standard 560sec did 0-62 in 6,6s and top speed 155...

That's the point, they perform fairly close. Little numbers are irrelevant even if that translates into multiple carlengths.

It was newer/looked better = buyers. Made to cruise comfortably at 90-130+ all day long and nothing else, the stock M70 and later 73 is plenty for that task.

[Corellian Corve]

Well, as it turns out, I have an '86 560sec. Mint, two-owner and very well maintained with only 79K miles. It's been de-catted with a magnaflow exhaust (which saves weight) and it's the other of the three cars I tested. Avg. 0-60 on that car was 7.1 seconds.

There is no way stock that was a 6.6 second car. I drove it in 100% stock condition and that thing was even slower. My father-in-law has a 560sel which isn't THAT much bigger and is equally as mediocre.

I would like to see an actual vintage road-test showing a stock 560sec getting 6.6 - I've also seen reports in the 8's which seem much more likely to me.

Don't get me wrong - the 560SEC is a sweet car. I love it. It's nearly a decade older, much bigger, and only 1/2 second slower is pretty admirable and I LOVE that car.

Back to the issue at hand -

A 1996 740i was 0-60 in 7.6 and that would have had the same motor as the '97 840 (M62). So the 8 series WAS faster than the 7 series of the time.

In 1998 BMW upgraded the V8 to the M62TUB44 which had 50 more HP and almost 100 more lb/ft. I can imagine that if BMW had stuck with the 8 for another 2 years, they could have put that motor in and it would have been awesome. Even better, would have been an 840csi using the S62 from and M5. What a car that would have been!

Also, a '94 Mustang GT was NOT a 6 second car. Motor Trend tested that car (you can find the article online) and it was tested at 6.7 secs and that was the 5-speed version. So again, as I've said, the 840ci was not a "slow" car of the period. If you wanted a super-fast 8, you could get and 850csi which, at 5.7 0-60 would have been the same as the Corvette and one of the faster cars available unless you stepped-up to a F355.

Regardless, the base 840ci was perfectly fine for the time. It was a GT car, not a sports car. Even 928s (not GTS) of the time were 6-ish second cars.

[Mikekugel]

[QUOTE=Corellian Corve;29751230]Well, as it turns out, I have an '86 560sec. Mint, two-owner and very well maintained with only 79K miles. It's been de-catted with a magnaflow exhaust (which saves weight) and it's the other of the three cars I tested. Avg. 0-60 on that car was 7.1 seconds.

There is no way stock that was a 6.6 second car. I drove it in 100% stock condition and that thing was even slower. My father-in-law has a 560sel which isn't THAT much bigger and is equally as mediocre.

I would like to see an actual vintage road-test showing a stock 560sec getting 6.6 - I've also seen reports in the 8's which seem much more likely to me.

Don't get me wrong - the 560SEC is a sweet car. I love it. It's nearly a decade older, much bigger, and only 1/2 second slower is pretty admirable and I LOVE that car.

Back to the issue at hand -

A 1996 740i was 0-60 in 7.6 and that would have had the same motor as the '97 840 (M62). So the 8 series WAS faster than the 7 series of the time.

In 1998 BMW upgraded the V8 to the M62TUB44 which had 50 more HP and almost 100 more lb/ft. I can imagine that if BMW had stuck with the 8 for another 2 years, they could have put that motor in and it would have been awesome. Even better, would have been an 840csi using the S62 from and M5. What a car that would have been!

Also, a '94 Mustang GT was NOT a 6 second car. Motor Trend tested that car (you can find the article online) and it was tested at 6.7 secs and that was the 5-speed version. So again, as I've said, the 840ci was not a "slow" car of the period. If you wanted a super-fast 8, you could get and 850csi which, at 5.7 0-60 would have been the same as the Corvette and one of the faster cars available unless you stepped-up to a F355.

Regardless, the base 840ci was perfectly fine for the time. It was a GT car, not a sports car. Even 928s (not GTS) of the time were 6-ish second cars.[/QUOTE
Having owned an 87 928s4, which I enjoyed, as well as an 86 944 turbo, I can say that a lower geared 840 / 850 will definitely put a smile on your face every time you drive it. Whether you choose to keep it stock in it's GT form, with a top speed in never land, or choose to drop the rear gear ratio, as I did, it is up to you. I can say that I do enjoy it much more withy lower gears.

[XAlt]

Well, as it turns out, I have an '86 560sec. Mint, two-owner and very well maintained with only 79K miles. It's been de-catted with a magnaflow exhaust (which saves weight) and it's the other of the three cars I tested. Avg. 0-60 on that car was 7.1 seconds.

There is no way stock that was a 6.6 second car. I drove it in 100% stock condition and that thing was even slower. My father-in-law has a 560sel which isn't THAT much bigger and is equally as mediocre.

I would like to see an actual vintage road-test showing a stock 560sec getting 6.6 - I've also seen reports in the 8's which seem much more likely to me.

Don't get me wrong - the 560SEC is a sweet car. I love it. It's nearly a decade older, much bigger, and only 1/2 second slower is pretty admirable and I LOVE that

You're down 60hp from the Euro.

I can see 6.6 seconds.

[Corellian Corve]

You're down 60hp from the Euro.

I can see 6.6 seconds.

Totally. Which is why I'd love to know what the US testing was. If it's stock 8's, then i'm feeling SUPER good about mid-sixes

- - - Updated - - -

Having owned an 87 928s4, which I enjoyed, as well as an 86 944 turbo, I can say that a lower geared 840 / 850 will definitely put a smile on your face every time you drive it. Whether you choose to keep it stock in it's GT form, with a top speed in never land, or choose to drop the rear gear ratio, as I did, it is up to you. I can say that I do enjoy it much more withy lower gears.

Funny, I have an '88 924s and '86 928s 32v (which has the Portken chip in it) and so I'm anxious to see what that does. I'm guessing since my car collection appears to be the mid-6 collection, that's where I'm placing my bets.

[toomanyparts]

You have a lot of (nice) cars. However, I couldn't care less about 0-60 times in a two ton vehicle, but still an interesting discussion.

[clubE31]

Major complaints (850) when it came out: slow, heavy and bad handling (did not change haha)........ but stunning looks.

Want a faster car buy a newer car (it is 25 years old....).

[mikae31]

Good discussion. I guess i have to put my 3,91 in and see for myself what it does.

[Hyper]

May I suggest that the "0-60" test is a poor choice for measuring the effect of a diff swap.
Conversely, a diff swap could radically impact your in-town joy but show up as a yawn in the 0-60.

Let me be a geek for a half-dozen seconds...

A 0-60 run can be broken down into its major components.
- The climb out of the torque hole below 4K
- The 1st sweep thru the power band, 4K-6.5K
- The gear change
- The 2nd sweep thru the power band

As for the gear change, the engineers have the choice to slam it thru hard or flare it over time while pulling back on power.
Just sayin', the '97 840 has the lighter duty 5HP24 in a car tuned for comfort.

Disregarding the gear change "for just a second", the two sweeps thru the power band take up two-thirds of the run and where speed gets tack on fastest.
The diff swap alters the time on the first component, to exit you faster out of the throw-away part of the curve, but changes nothing on the all-important other two-thirds of the run.
Using the TUB44 vanos engine versus the B44 changes the two sweeps thru the power band because 1) the vanos engine has a wider, higher curve and 2) the good stuff arrives earlier in the climb.

As the footnotes in the B46 project reveal, there is yet another particularly important "defect" in the factory tuning.
The AFR never drops out of an economy tune, even under WOT conditions which is the only condition present in a 0-60 run.
This caught the attention of the dyno tech ("Whoa, that's weird") and hamstrung the 840/B46, running on the orignal ecu tune, to "just" 5.97seconds.
I still owe my fix for that and would be surprised if 1) the 840/B46 (w/3.15) is not at around 5.85s, and 2) the 840/B44 is not at around 6.4s.

Now a change in AFR to improve WOT power is not significant for typical driving conditions so, even though the 0-60 is now more marketable and more quoteable on the forums, your in-town joy would not improve.
Rather, you should have spent your time and money on diff gears.

********
While I'm in here and having done "a few" runs using the '97 840 (3.15) + Gtech...
- Checked google, I share a similar elevation as the OP, and I also standardize on an air temperature and humidity.
Blah-blah, the air density, while significant, is likely equivalent.
- Just fyi for people without instrumentation (or iPhones), 0-60 runs produce a bell curve spread with standard deviations.
For instance if 6.6s is reported, samples recorded might actually extend from 6.45 to 6.75, but with 6.6 being quite routine.
- The difference between an empty and full tank tended to be about 0.2s.
- As OP reported, sport mode does not alter what occurs in a 0-60.
It doesn't alter what gear to select, and if the single shift did occur faster, that's only a small component of 0-60 anyway.