lol i would love an svt...but would rather get a truck...so the focus is only temporary till i get out of school. the gas milage difference is incredible, i gained 5 mpg's when i took all of my equipment out.

5mpg, no way.

You aren't going to gain hardly anything, but a loss of output. Either way it is your choice, but you get to pick the compromise.

ur right, it was only four miles per gallon...do u think the output loss would be noticable?

Lol. If that is truly the case, which I doubt, it isn't because of the weight. Unless of course your system for some ungodly reason is ridiculous in weight. Considering you will find ZERO difference in mpg switching from an 18 to a 15 and changing your enclosure.

it might not be the weight, ur right, but i am getting about 4 more mpg, i think it might be because there isn't nearly as much draw of power (alternator kicking on) so either way im going to be getting lower mpg, my main reason for asking about going to a 15 was because of the backseat, while i dont mind not having the backseat i was just wondering if it was necessary if im not going to be able to hear the difference between a 15 and an 18. im just going to go with the 18. thanx for all ur help.

it might not be the weight, ur right, but i am getting about 4 more mpg, i think it might be because there isn't nearly as much draw of power (alternator kicking on) so either way im going to be getting lower mpg, my main reason for asking about going to a 15 was because of the backseat, while i dont mind not having the backseat i was just wondering if it was necessary if im not going to be able to hear the difference between a 15 and an 18. im just going to go with the 18. thanx for all ur help.

In that case, if having a backseat is worth the financial difference then go for it

it might not be the weight, ur right, but i am getting about 4 more mpg, i think it might be because there isn't nearly as much draw of power (alternator kicking on) so either way im going to be getting lower mpg, my main reason for asking about going to a 15 was because of the backseat, while i dont mind not having the backseat i was just wondering if it was necessary if im not going to be able to hear the difference between a 15 and an 18. im just going to go with the 18. thanx for all ur help.

Your alternator doesn't "kick on", it doesn't have a clutch like an AC compressor. Whenever your engine is running, your alternator is charging.

Take the parameters of your NS 18" and compare it the 15" your wanting to buy and plot them on WinISD to see the difference in output. Make sure you put in your own box designs. Not a true comparison but it's a start.

it might not be the weight, ur right, but i am getting about 4 more mpg, i think it might be because there isn't nearly as much draw of power (alternator kicking on) so either way im going to be getting lower mpg, my main reason for asking about going to a 15 was because of the backseat, while i dont mind not having the backseat i was just wondering if it was necessary if im not going to be able to hear the difference between a 15 and an 18. im just going to go with the 18. thanx for all ur help.

Your alternator doesn't "kick on", it doesn't have a clutch like an AC compressor. Whenever your engine is running, your alternator is charging.

That's partially correct. There is no clutch on your alt, but the alt does not charge to it's full capacity at all times. So, if he is running a power hungry amp, it will strain the alt and make her charge at a higher amperage than usual to compensate for the voltage drop that is occuring. Will that make for more resistance on the alt/ drivebelt system? I'm not sure........

it might not be the weight, ur right, but i am getting about 4 more mpg, i think it might be because there isn't nearly as much draw of power (alternator kicking on) so either way im going to be getting lower mpg, my main reason for asking about going to a 15 was because of the backseat, while i dont mind not having the backseat i was just wondering if it was necessary if im not going to be able to hear the difference between a 15 and an 18. im just going to go with the 18. thanx for all ur help.

Your alternator doesn't "kick on", it doesn't have a clutch like an AC compressor. Whenever your engine is running, your alternator is charging.

That's partially correct. There is no clutch on your alt, but the alt does not charge to it's full capacity at all times. So, if he is running a power hungry amp, it will strain the alt and make her charge at a higher amperage than usual to compensate for the voltage drop that is occuring. Will that make for more resistance on the alt/ drivebelt system? I'm not sure........

I know its not always charging at full capacity, but it is always charging when the engine is running. I'm pretty sure that there is no increased resistance to the drive belt when the alternator is putting out higher amperage, I don't see how there could be.