I just ordered oen of those./....BUT HOW ACCURATE ARE THE THINGS>?>?>> OMG I paid like $40 dollaz off ebay. I ant skared son. What do i need to be able to realy on this thing. I realzie hthat it aint like the trac but hoow close? thanks!!!! friendZ
Chill bro. They are ok... wont give you an exact readion but once you do mods you will be able to see the increase... They basically go by how much they tilt when you accelerate to get your hp very touchy things and they have to be exactly level to work properly.
They are as good as the data you put in them. You have to have the correct weight, so a too full/too empty gas tank can skew the results. You have to make sure that the road is level. You have to correctly calibrate for how much your front end rises and your rear end squats on acceleration.
If you get all of that dead on, they are suposed to be nearly as accurate as a good chassis dyno. If you always test at the same place, always fill up before testing and independently confirm the results at a drag strip fairly often, the data should remain very close and give you good back to back results.
So, if you test, change something and test again, you will be able to see fairly small changes, probably down to 3-4 hp.