What do you lose in MPG????

[theROOSTER]

with various mods?

We have a 2002 MP5, 125k on the clock we bought used 3 months ago, pretty much 2nd car mostly for my wife. (but I LOVE driving that thing!)

I found this forum (yay!) and hit some stuff right away with the "how to's"
-seafoamed the engine
-cleaned injectors/tank
-cleaned EGR
-cleaned IAC
-fixed/replaced crappy stock antenna(lol)
-dropped in new Plugs (went with the "G-powers")....
-dropped in a new K&N oiled air filter

first go-round after the seafoam and new plugs, I netted 23 mpg on that tank. since things have "settled in", I've been netting 29.2 mpg last 2 tanks, combo street and highway - not too bad!!!!

I wouldnt mind adding a couple "tweaks" here and there, such as :
-MP3 or MS3 17"'s with 45 tires
-Cold air intake/filter
-racing beat (or simular) cat-back exhaust
-high-flow cat

hopefully, the last 3 I can find 50-state legal, being in CA where they HATE eveything emissions related....

anyway - in general, more power = less mpg, and same for increasing your rolling diameter and resistance...


would I be looking at "substantial" MPG loss with these? (lets say, loss of 5-7 overall, down to 24-22) , or will it be negligible? (smash)

 

[Salmon_Rob]

youd gain mpg with those mods. injen intake and k&n are smog legal. racing beat is 50 state legal. the high flow cat would be trickier

 

[Lord_Zath]

Adding the 17" wheels you'll find the car is much heavier, meaning slower acceleration and worse braking performance. I had MP3 rims on for a while and one of the reasons I got rid of them was I also noticed a dip in gas mileage as well as the above...

 

[theROOSTER]

ah, cool - thanks on both replies... maybe I'll keep it to a cat-back for now, and an in-take as time allows.

17's look great, but not a neccessity, so I'll probably keep the stocker 16"'s for now (which look fine) and try 205's when I need new rubber...(which I know I'll lose a smidge MPG) maybe drop a stiffer lower sway bar in too...

 

[fishdonotbounce]

A progress rear sway bar is one of the best mods I've added to my car. The MX-6 rear strut bar is also a very great and inexpensive mod found in the HOW-TO section.

 

[Lord_Zath]

yeah my plan is to go to 205 tires as well w/the stock rims once my stock tires wear out...

 

[ucMP3]

Might as well go with 215

 

[P-Funk!]

Wider tires improve handling - but increase rolling resistance and decrease fuel economy.

Meh. Better handling FTW!

 

[Mike R]

CAI will lose MPG, just due ot the fact cold air needs more fuel. Really bad in the winter. (which in CA prolly isn't nearly as bad as MD)

I get 30-35mpg with an OBX header and VTCS removal. Those two are mods that will get you some really nice gains for the money. Add CAI and muffler, and get a bit more top end power.

 

[P-Funk!]

^yep. Me too. 34 MPG with my mods (see sig)