Anyone else with their GTech's hardwired, have problems with the Gtech giving incorrect readings? I'm thinking I may have to recalibrate it... But the other day I was on a nice clear strip of highway, no twisties or anyone in front of me or anything, and decided to let it go.

Pulled a 6.4 second 60mph, which I think is decent considering I still suck at manual sticking, and I don't practice take-offs, nor do I drag...

But other than recalibration, could it be anything else? I have the vehicle weight programmed in at 3200lbs, mostly because I don't know what the actual weight is... I will weigh it eventually... But I think it was reading accurately before, though I can't compare now.

The most obvious thing that was off to me, was that the speed on the speedo, was about 25% more than the Gtech said I was doing. So if the speed is that far off, so could my 0-60 times, and other things like whp readings...

Any help, tips, suggestions appreciated.

 

you really have to wire it directly to the battery for it to work.

 

I have it wired to the jump-start tap next to the air intake. The RPM's read correctly, and don't jitter like they did when plugged into the factory outlets. I don't think that's it...

The only other thing I can think of is that I'm using 18" wheels now... Which is the only change from before when I was using it often.

 

I think you need to get it weighed quicker than you think, 3200lb is way off the mark.

 

The stock weight of an MCS with about 1/4 of a tank of fuel is roughly 2460lbs.....3200lbs is waaay off, which may be why the readings are off?

 

The problem seems to be with the longitudinal accelerometer. There's a quick calibration setup that you can do, and I think the manual actually gives two different methods to do it.

Also, are you positive that your G-Tech is perfectly level? If it's pitched forward or backward you'll get skewed results.

As an aside, mine works fine off the cigarette lighter, and reads RPM's just fine (well, it's consistently 100RPM low, but consistency is key).

 

On what planet does a stock MCS with 3 gallons of gas weigh 2460? On planet earth it's more like 2640lbs and that's a little low for most. Packages weigh quite a bit, and stock S-lites with RF weigh a ton (figuratively.) Check out the thread on the general forum called "I weighed my MCS". Coopers with few packages weigh about 2450-2500 and very few MCSs weigh less than 2500lbs. A good start would be 2600 especially if you have some aftermarket goodies that shave weight (wheels, exhaust, brakes.)
cheers, phil

 

I've been on level ground, and been within .01g's of level when starting a run... I will do the calibration again though... I did it last fall, and maybe it needs to be done every once in a while...

And I put 3200lbs because I didn't want a false-hi HP reading because I was too low... I read somewhere that the mini was about 2600lbs empty, so I assumed full of fluids, my gadgets, and me, that it would probably be closer to 31xx something, so I rounded to 3200.

Interesting thing tho... My last few runs the Gtech has reported 180hp (engine hp - wind/drag - drivetrain - etc...). I'm curious how accurate that is.

 

i was merely going off what it says on the website. 1 L of gas is about 0.62 kg, and i assumed no driver/luggage weight. I didn't take into account any packages...

 

Find any commercial scale and get it weighed. You wont have any type of accurate number until you do.

John

 

Your logic is backward on this. Reporting a higher weight will make the Gtech believe you can accomplish massive acceleration with a large mass, which will read higher in horsepower. Reporting a lower weight will tell the Gtech that your massive acceleration is due to the fact that the car weighs next to nothing, which doesn't require much power.

Remember, too, that you're getting net horsepower, not crank or even wheel horsepower. Net horsepower is affected by drag, and you can use this handy calculator to figure out how much you're losing to drag.

Try entering 20sq-ft for the frontal area. That's close to right (5' wide x 4' tall), or at least as close as I'm going to get. You'll probably discover that you're losing another 10% (or more) to drag.

Anyway, don't trust that 180, because it would mean you're getting closer to 220 at the crank, and that's crazy talk.