Dash mounted performance detector (0-60, HP, etc.)

Sunday afternoon a friend came by with one of those "stick-it-to-the-window-performance-detector" things that he borrwed from a co-worker. I've seen them advertised but can't remember what it's called. We went out in his stock 99 996 and my 94 C2 w/ MAF & chip. We found a nice long flat road in an industrial park (Sunday afternoon) and did some 0-60 runs with both cars. It was a blast! First time I ever smelled my clutch burning!

Not sure how accurate this thing is but all my 0-60 times ranged from 5.85 (two people in car) down to a low of 5.05 (solo) on the perfectly flat section of road. If you started a bit further up, there was a slight dip in the road which flattered me with a 4.94, but I won't count that one. His 996 was comparable, with a 4.5 using the dip in the road. Think he may have hit 4.9ish on the flat (not sure).

Has anyone tried this thing? Is it accurate, or just fun? Can these things be calibrated for accuracy? I know it can calculate HP, 1/4 mile, etc., but we didn't have instructions and were having too much fun cooking our clutches on 0-60 sprints.

Those numbers definitely make me envious of your machines!
The accuracy is to within a hundredth of a second, but there are things to consider; namely how level it is an so forth.

Also I assume you're talking about the G-tech Pro.
What impresses me most in that is the numbers your 94 C2 is producing with respect to the 996. So you have the best looking 911 ever made along with performance that is very near that of the 996

I have one of the G-tech pro things. They're pretty consistent, but that's an optomistic consistent. If you have a perfectly flat piece of road, they are usually 2-3 tenths optomistic (i.e. if you get a 4.9 on one run, you're actually at 5.1-5.2). The 1/4 mile times are optomistic also, and the trap speeds are optomistic by about 3 mph. But they are consistent, neato tool imho.

Brad

Mike,

What RPM did you launch at to achieve the times for your C2? Did you side step the clutch?

I'm wary of harsh launches on my C2 because I don't want to wear out my clutch. I've tried it a few times and got either severe wheel hop or the engine bogged down.

Actually, is the engine bogging down the sign of a problem? As I recall, I revved the engine up to 3000 rpm and let the clutch out quickly (didn't side step though), and the rpm's dropped to near 1000 bogging the engine down before the car took off. I haven't tried to launch the car from a standing start since then for fear of doing damage. Any thoughts?

Drew
92 C2 Coupe

I think you are refering to the G-Teck Pro, which does all the messurements you mentioned. Thats great it gave you low numbers, because a friend of mine bought one, and it gave us times like 0-60 in 16 sec and 1/4 in 18 sec. This test was done on a freshly rebuilt stock SC, that I estimate (with a stop watch) was doing 0-60 in 6.5 sec and 1/4 mile in 15 sec. We then did a test in a 84 Carrera with lowered gear ratio. The car feels fast because the "torque feel" of the transmission, but I do not beleave it is much faster than a stock SC. The numbers for this test came up 0-60 in 4.8 sec and 1/4 mile in 9.8 sec. No way was it right! I think it has to do with how much the car lifts in the front end that makes the difference. I was going to buy one until I saw how bad his was. However, it sounds like you were getting a little more consistant times. Maybe they have improved them in the last year since my friend got his.

Love the smell of burnig tires and clutch also, just do not like paying for them

Paul
81 911SC

yeah, those numbers are way wrong, but the original poster's numbers sound close. '84 carrera does about a 6 and 14.5.

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it's all the chronometer...

Drew,

It took a bit of trial and error before I found the best combination. I, too prefer to baby my clutch in normal driving but this was just one of those things (we've all been there). I have to admit that the smell outside the car after a hard run was a bit unnerving! The 996 smelled the same way.

No, I never side-stepped the clutch. What worked best was to rev to about 3800-4000 and floor the accelerator as I quickly, but smoothly lifted off the clutch. The thrust is breathtaking. My shift to 2nd was at the re-line +/- 100 rpm. Unfortunately, I didn't make that shift as quick as I would have liked (or at least it seemed that way). Practice will improve it but I'm apprehensive to burn up my clutch by overdoing it. The 996 had it's stock chip and would stumble (rev-limiter) at red-line which probably cost a few hundredths on a few runs. The feeling of acceleration as a passenger on some of his runs is intense (much moreso than in the driver's seat - why?). I even felt a bit of motion queeziness on one run. Don't underestimate the stock 996, it's wicked fast.

Honestly, I was surprized with my times. I never expected to break 6 seconds, that's why I asked about accuracy. I think my friend was surprized as well. We agreed to trade cars for a few runs also. He hit low 5's in my car, and I did about the same in his.

I went home r-e-a-l-l-y psyched with my car. I'm planning to replace my primary muffler with a cup pipe next weekend...mostly for the sound but it'll be interesting to see how the ol' butt-dyno reads.

Best, Mike (grinning ear to ear).

I've heard of quirky g-tech pros, I guess every manufacturer has quality control problems, but mine has worked great - haven't tested it on the 911 but got consistent 5.3-5.4 0-60 and 13.9-14.0 1/4 mile times with trap speeds around 103 mph in my chipped 97 M3 which is right on for that car (make sure you find a good and isolated straight stretch so you won't attract attention from the law or anyone else). Keep in mind that violent or shaky launches might confuse the thing - the smoother the better - and the softer your suspension, the more error you'll get (although I don't think many of us have to worry about that). If anyone in or near NYC would like to try one I'll let you borrow mine

I have a performance meter for my car, it is made by a company called race technology (try their web site www.race-technology.com ), it is very accurate and a joy to use and abuse! Have had readings of 6.13 0-60 in the damp.

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82sc

As the owner of a G-Tech pro, I recommend something else. It's accurate but very limited in its use...no downloading to pc or memory or anything of the sort.
Lookins like the one IDrabble suggests may be the key --the AP-22 which will allow you to archive your data, as well as do max force measurements for any distance rather than just the limitations you're given by G-tech.


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Kurt B
1984 911 Carrera Cabriolet