Does weight matter on a Dyno?

[Turblown]

I know it kinda sounds like a dumb question... but does it matter?

I mean, if I get my car dynoed with the spare tire and sub boxes still in I'm thinking I'll get the same results as if I lightened the load. I know it makes a difference in the 1/4 mile... but the dyno only measures the power sent to the wheels, not under "load". The dyno in a sense is the "load" on the car... and not the car's weight.... right? Does it make a difference if its FWD or AWD?

Let me know your opinions... planning a trip to the dyno (after I get some decent mods going) and I'm wondering if temporary weight reductions would be a waste of time or not.

 

[bigjangin]

On a dyno, the weight of the car absolutely doesnt matter. This is fact.
On the track, the weight of the car matters a whole lot. This is fact.

Look at it this way. If you ripped the shit out of your car and it weighed 500lbs less would your car's engine make any more power? No. Would the car be faster? Yes. Its simple physics.

 

[n3gativerr0r]

Only time weight is gonna matter on the dyno is the weight of your rotating mass. The heavier your drivetrain including wheels the more parasitic loss you will see and the less power you put to the ground. Hence a FWD DSM will put more power down on the dyno than a AWD DSM with the same setup.

Alot of people neglect shaving weight, especially in the drivetrain area. For AWD cars especially you already have a lot of mass to rotate. Ive seen 3 tenths drop in quatermile with a .15 drop in 60ft time by someone just going with a lighter rim with the same tire. I think the calc was something to the effect of every 1lb off the rotating mass is equal to 6lbs of non rotating mass removal. So going with a Rim/Tire setup that is say 15lbs lighter per wheel than stock can net you some pretty serious gains.