G Tech

[stats007]

BHP are as accurate as the weight figure. The rest is just maths. Mass, Accelaration, Time, power required to move that mass. The unit claims +/-1bhp. Given I've already dynoed my car the figures make sense.

Gravs figures need to be taken in the context that he had 50 large magnets in his boot at the time of the test............no dont ask!

You're right to a point - the maths doesn't and can't allow for clutch / torque converter slip and wheel spin. The road also has to be perfectly level and the unit itself mounted completely level or the accelerometers give readings that can be interpreted as inaccurate. For a general idea the figures are fine but I wouldn't challenge road tests results.

 

[R2D2]

How do you think road test results are tested if not by using accelerometers? Thats what all the magazines do. The advantage an accelerometer has over a dyno is the engine gets air at the proper volume. It would be some fan that could pump air in the volume a car needs at high speed.Anyway at the end of the day its all a bit of fun.

 

[R2D2]

That'd be Sabine I expect (the German girl who's a Nurburgring expert)!

Nope the big bloke next to me was no Sabine!

 

[stats007]

Given the nature of the testing and the road required. Grav and I agree that it would be imprudent to arrange a GTG for G tech testing. I will however, either rent it out for a nominal amount and a confirmed address to send it to or sell it if someone makes a decent offer. I know all I need to know about my car.

Just go to Croydon - they have been running illegal race meets on an industrial estate for years with the full knowledge of the Police.

 

[Shude]

BHP are as accurate as the weight figure. The rest is just maths. Mass, Accelaration, Time, power required to move that mass. The unit claims +/-1bhp. Given I've already dynoed my car the figures make sense.

Does this not assume that you do a perfect launch and perfect 0-60? No matter how badly you change gear and no matter how much you wheel spin on take-off the torque/bhp figures should be the same. How does the G Tech factor that into it's equations?

 

[R2D2]

The unit only measures from when you move not when you fudge you start or spin your wheels it measures only when the think accually moves. It has not 1 but three accerometers and copes with changing rates of acceleration. So in a power run you can slow down and accelerate as you are driving and it gives you a real time bhp figure. Grav saw this effect today. It also tells you if the car is pointing up or down a slope and if the car is tilting. I know it sounds bizarre but it is so impressive to use!

This article explains better!

http://www.mustangworld.com/ourpics/hitech/gtech1.htm

 

[stats007]

It's not bizarre it's quite simple really - gyroscopes do the same thing! Accelerometers measure longitudinal and lateral accelleration - calculating bhp from this makes assumptions that there is a direct transfer of power - clutch slip and wheelspin make these calculations inaccurate. What does interest me is how they read the rpm through the cigarette lighter!

 

[R2D2]

We were getting quite good at not having wheel spin and given that grav and I both drive autos we didn't muck up the gear changes and were pretty consistent on timings. All our 0-60 attempts were within 0.5 of a second of each other regardless of which strip of road we were on. My overall feeling is that the G tech is a lot better than a dyno run!

 

[Bobby Dazzler]

I think the key here is to remember that this device does not measure the BHP, but calculates it based upon assumptions.

No different to a chassis dyno really, as it measures power at the wheels and then calculates the flywheel figure, again based upon assumptions.

The only way to measure power at the flywheel is to whip it out of the car, and pop it on the bench!

Measuring RPM through cigar lighter intrigues me too!!

 

[stats007]

A chassis dyno is more accurate for wheel horse power as there is direct measurement and not theorising about unknowns - even so here you should do a 'best of 3'.

 

[machasm]

I think the key here is to remember that this device does not measure the BHP, but calculates it based upon assumptions.

No different to a chassis dyno really, as it measures power at the wheels and then calculates the flywheel figure, again based upon assumptions.

The only way to measure power at the flywheel is to whip it out of the car, and pop it on the bench!

Measuring RPM through cigar lighter intrigues me too!!

I don't believe that it requires your RPM nor makes any attempt to read it through the cigarette lighter or otherwise.
Is that right R2D2?
Mac.

 

[R2D2]

I don't believe that it requires your RPM nor makes any attempt to read it through the cigarette lighter or otherwise.
Is that right R2D2?
Mac.

I dont really know is the honest answer. I did read somewhere about RPM sensing but I honestly dont know!

BTW. If anyone wants to do their car then I can post it to you for £10 (P and P and a bit towards its Purchase in the first place!) Payment will be by Paypal and I will only post to a confirmed paypal address or guys I already know.

Alternatively make me a reasonable offer and the kit is yours!

OR. come to me in medway and I'll do it for free!

 

[GRAV888]

Guess we must have looked at the wrong car in the handbook
My car weighs 2210kgs x 2.2 = 4862 lbs.
I need to have another go Greg

 

[stats007]

I don't believe that it requires your RPM nor makes any attempt to read it through the cigarette lighter or otherwise.
Is that right R2D2?
Mac.

From Tesla's (the manufacturer) website:

We are particularly proud of our ability to gather RPM data right through the cigarette lighter which allows us to have Torque measurements along with Sequential Shift lights and RPM replays. We are the first in the world to do this.

I presume they pick up some voltage variation or noise interference usually associated with a suppressor.

 

[R2D2]

Guess we must have looked at the wrong car in the handbook
My car weighs 2210kgs x 2.2 = 4862 lbs.
I need to have another go Greg

Fear not, I wrote all the readings down. A weight of 4862lbs= 332RWHP therefore assuming the 22% per cent losses as calculated from the previous dyno sessions= 425bhp

You're sure that figure isnt the gross weight though?

 

[GRAV888]

Fear not, I wrote all the readings down. A weight of 4862lbs= 332RWHP therefore assuming the 22% per cent losses as calculated from the previous dyno sessions= 425bhp

You're sure that figure isnt the gross weight though?

I'll go round to Day Aggrigates tomorrow and put it on the bridge.

 

[pammy]

I would love to know Edna's figures Will work out some where where I could test her out then be in touch

 

[R2D2]

From Tesla's (the manufacturer) website:



I presume they pick up some voltage variation or noise interference usually associated with a suppressor.

Well done thats the bit I read before!

 

[R2D2]

I'll go round to Day Aggrigates tomorrow and put it on the bridge.

These places will be making a fortune from us! Let us know the result and we'll recalculate.

 

[R2D2]

I would love to know Edna's figures Will work out some where where I could test her out then be in touch

Shame you are not local