Guys, I got the GMeter GT2. I loooooooooooove this product! Check it out in the attachments

 

I think that you should forget about the timing equipment and go and enjoy yourself... and if you are new to track driving, get an instructor.

 

Chad's right - the only way the G-Tech knows the engine RPM is to detect it through electrical engine noise in the power connection. The problem is, the power going to the cigarette lighter in the MINI is pretty well-filtered, so the G-Tech can have a hard time sensing the engine RPM through that connection. Chad is one of the lucky few MINI owners that's been successful in that regard. I had to connect mine to the fusebox under the hood to get a good signal.

The G-Tech can actually perform most of its measurements without a good RPM signal, though. Things like lateral/longitudinal g-forces, acceleration times, 1/4-mile and 1/8 mile times, braking times/distances, and even peak horsepower and torque don't require an engine RPM signal. The only thing you really *need* the engine RPM for is if you want it to display a "dyno-style" graph of HP & torque versus RPM. I also use the RPM function when autocrossing to determine my maximum RPM during a run. That way, I can tell if I can downshift during certain parts of the track during the next run without hitting the rev limiter.

 

If this is right, why you have to input so much details on your car? Weight, CDC and other stuff? I think G-Tech does SENCE the power torquing it, and it needs those data so it can CALCULATE acurate HP and torque...

 

True - the G-Tech does need the total vehicle weight, but that's only to calculate horsepower. I don't know what "CDC" is, and I don't recall having to enter it into my G-Tech.

The *only* things that the G-Tech actually *measures* are acceleration, time and engine RPM. Everything else is mathematically derived from those numbers and the weight of the vehicle.

The G-Tech has no way of knowing how fast your engine's turning, unless you could enter in your transmission gear ratios, differential ratio, and tire diameter. Rather than doing that, you just program in how many cylinders your engine has, and it listens for electrical noise in the power connection to determine how often the cylinders are firing, and uses the number of cylinders to convert that to an RPM.

One correction to my earlier post - now that I think about it, although the G-Tech can calculate horsepower without engine rpm, you do need the engine rpm to calculate the torque from the horsepower.

 

So, if I enter the weight and connect it to the fuse box I'll be fine? Would you please tell me how much does a cooper s 2006 weight? empty and does not matter full of gas or not.

 

Yep, that's all you should need to do - enter in the vehicle data and plug in the power (either to the lighter socket or the fuse box, whichever works best).

As for the weight, it varies depending the options you have, but the advertised curb weight is 2679 pounds. Don't forget to add in your own weight.

 

Horsepower = ( torque x RPM ) / 5252

 

Let's assume this is right. Yesterday I did my first run. With the mods I've got and a default weight of 3000K, I've got 176 peak HP. That is what made me wonder if it's really right. If you in details with the product manual, there are quite many things you have to input so you get actual HP. Like the power loss, if it FWD or 4WD or RWD and so many many things which are hard to get. CDC is the air resistance against the car's body.

 

Are you using the G-Tech Pro or another system? I really don't remember being able to enter things like predicted driveline power losses and drag coefficients in my G-Tech Pro RR.

As mentioned earlier, the G-Tech and similar devices measure *wheel* horsepower, minus the power required to overcome air drag. All of the corrections you mentioned (driveline loss, drag coefficient, etcetera) are only useful for trying to "work backward" from the "wheel horsepower with drag" number to figure out the actual horsepower at the crankshaft.

If you're trying to judge the effect of new modifications, you can just use the "wheel horsepower with drag" number and forget about all the correction factors. The important thing is how the horsepower number changes after a mod, not what the actual number itself is.

Was the peak reading of 176 HP taking into account driveline losses and air drag, or was that just the raw reading without any correction factors put in?
If the 176 HP was what you were *actually* getting at the wheels without any correction factors, that's really good. Figure in air resistance and driveline losses, and you're probably past 215-220 HP at the crankshaft. (Which is about where I'd expect you to be, since you basically have a JCW engine with a slightly higher-reduction pulley than the one that comes with the JCW kit)

 

Hello Scott. This is the one I got. [SIZE=3]Escort Passport GT2. I love it so much.[/SIZE]

 

I can not list down all the drfault configuration that come loaded on the deivce, but the one I'm sure of is that it comes in UK measurement system and assuming car's weight is 3500KG or 3000Kg. My trial was even before I read the manual so when I'll update the car weight today I should get better than the 176. I'll keep you posted. If you like, I can get you the e-manual.

 

Just a small correction Scot; I have stock engine running CVT tranny. Only the mods that are listed below. Well, after the upgrades, I never dyno'd my car but I kinda expect it to be around 200HP cranck.

 

I didn't think you could get the CVT transmission in the MCS. In fact, I'm almost positive you can't.

And if you have a reduction pulley, JCW ECU, JCW intake, JCW ECU and JCW injectors, that's practically the entire JCW kit except for the cylinder head. That's what I meant about you basically having the JCW engine.

 

Well, my car is automatic, what do you call it? Steptronic? I have the gear shifting paddles in the steering wheel as well.

 

But anways, you made me dying more and more to update the car weight and re-test it tonight!!

 

you have a unit that is measuring power from how fast that car moves through air! So if the unit can have the Cd (co-efficient of drag) and frontal area in, it may compensate for that, I don't know, I never used the Escort GT2. But if your driveline losses are about 10%-15% a 200 crank HP car will measure out to about 170-180 hp, right in line with what you're reading. (If I remember correctly, about 17-18 HP goes into moving the car through the air at 70 mph.)

As far as car weight goes, either get your car weighed (with about a half tank of gas and YOU in it) or just use an estimate and go with that. What you're aiming for (or should be aiming for) isn't nessisarily the most accurate number, but creating a measuring device that can see deltas. So what if it's off a couple of percent? (for fun, do about five runs right in a row and look at the max-min HP reading and the standard deviation of the measurements. It takes A LOT of work to get this under a couple percent.) Also, remember that gas weighs a lot (at least a full tank does) and this will effect total car weight, once again in the single digit percentage range.

Really, you are now more in the realm of measurment science than actuall car stuff, and breaking out the statistics books and then learning about accuracy vs precision will be time well invested.

Matt

 

Easy on me Matt! I'm doing this just for fun. At least, I'm going to have some solid base to know where do the mods I apply take me, better performance or not! I've always liked and respected your opinions...

 

Yeah, it sounds like this is a pretty simple unit, kind of overpriced really. All it is is an accelerometer with a processor to integrate its acceleration to find your velocity time-derivative and finally your position. It needs weight because it takes inertia into account. Amazing what a little programming and an accelerometer can do! Wish I had some more time on my hands it sounds like a fun project... maybe I could get credit for it in my Dynamics class??

 

it might be funny, but my GT2 showed:
-Before the pulley and near empty gas tank, I got 0-60 acceleration of 8.1 sec.
-After pulley installation, same gas level and same road, I got 0-60 8.6 sec.

 

I have a GT2 also (and noticed earlier in this thread there was some confusion because some people were talking about GTech's which are TOTALLY different units) - and with the auto tranny, how you launch is EVERYTHING.... I'm still working to get consistent launches.

But these units are quite accurate when timing runs on the same car withe the same settings. It's all in the technique.

The HP estimates are a little dicey given all the correction factors (frontal area and CD - known and easy to get right; rolling resistance, not so easy; drivetrain loss, also not so easy; etc.) but mine seem pretty reasonable.

 

Blimey, can you give me the known data for the GT2 that you have? Let me try to get more accurate numbers.

 

Granted, I have the GTech Pro RR instead of the GT2, but I can't think why any parameters you enter would cause your 0-60 times to be off. Messing up the frontal area, drag coefficient, weight, etcetera would cause bad horsepower/torque readings, but the 0-60, 1/8-mile, and 1/4-mile times should just depend on the internal accelerometers and clock.

 

Yeah, I agree with you Scott. I just wanted the info to update the GT2. But I'll be working hard on trying to know why after the 17% installation my times on 0-60 are getting worste!!!!

 

I agree.

The GT2 also has some correction factors to compensate for body roll side-to-side and front-to-rear (squat) for more accurate G-force reporting.

But, again, I don't think those will impact your acceleration/timing numbers.