G Graph

[EspenW]

The big test in Car & Driver showed the same thing. The G-Tech is very accurate:

http://www.caranddriver.com/reviews/hot_lists/high_performance/performance_files_tested_by_c_d/do_inexpensive_performance_meters_work_feature

The Performance Box is a (much) less expensive version of the Racelogic Vbox that the big magazines use. The Performance box retails for £329 incl VAT, so it isn't that expensive.
The advantage of GPS based measurements is that it takes vehicle squat and road grade out of the equation.

[Rusty]

That first peak is caused by the clutch grabbing after the gearchange. Do a pull from low to high rpm in gear to see real peak G's.
NB: The Mk1 G-tech will store max G's recorded.
However, get something with datalogging, it is so much more helpful than something that just reports peak values that are often caused by spikes.
I would look at the Racelogic Performance box if I were in the market for a performance meter.

The 0.5 was seen from a 2k-6k run in second, no spikes, the values went up and down smoothly and were around the 0.5g mark from 3k to 5k.

[S2central.net]

Interesting article from C&D on the subject... On todays money that £329 is pretty much $US500 - which is a mighty bit more than the G-Tech RR at its nominal $300 sticker price. I do like mine but I don't use it anywhere near enough - although its really quick and easy to setup - the windshield mount is really good. And just one cable to the ciggysocket for power is all it needs.