Hi! I have an '05 MCS with the 6speed manual tranny. I would like to increase the HP and I am considering a pulley change. Can I get more power but keep the MPG that I am getting now (25-28mpg for mostly in-town driving)? Is a pulley swap the best way to start or is it better to start with changes to the air intake system or exhaust system? If anyone lives in Washington State and knows of a good shop to go to for this kind of work, I would really appreciate the info. Thanks!

 

Well, the bad news is there's not much you can do to easily improve power without losing fuel economy, but the good news is that the typical intake/pulley/exhaust upgrades can net you a significant increase in power without a huge hit in economy, as long as you can "keep your foot out of it" after the upgrades.

 

Anything that makes the engine run more efficiently will generally net you better MPGs, IE a good header, exhaust, intake, lighter wheels etc.

 

I am about to find out... I am currently running a heavily modded setup and have actually already increased my MPG, and may have increased it more... its all in the tune... all in the tune.

 

The way the SC system is set up (having a bypass valve) adding a pulley shouldn't change anything while the valve is open thus not hurting MPG. Otherwise the general "more air+more fuel=more power" rule applies I would think.

 

Well, you're still spinning the supercharger 15-19% faster for any given engine speed, even if you're not making boost. And since frictional losses increase with the square of the increase in speed, you're looking at 30-40% more frictional losses in the supercharger assembly. Plus, you're spinning the water pump 15-19% faster, and that robs additional power as well.

Still, it's not a huge hit in fuel economy relative to the extra power you'll have on tap.

And AZblackOUT brings up a good point. It's possible to increase both power and fuel economy if you also re-program the ECU along with the mods. I think you'd have to reprogram the ECU with economy in mind, though - I don't think a max-power tune will automatically increase fuel efficiency as well.

 

Scott's right. Max power is around 12.8:1 A/F ratio... not exactly sipping fuel. I've done the intake, pulley, exhaust and I might have lost a mpg or two. I still average well into the 30's and have seen the OBC read over 36 or 37 when I don't have to run the A/C.

 

I actually gained MPG until I put on the DT BPV. Even with that, my car is still far lighter on fuel than it used to be in stock form if I'm driving civilized.

 

Same here... I've had my 15% and M7 CAI on for approximately 4,000 miles and have averaged about 1-1.5 better mpg's under the same driving conditions as before the pulley and CAI install. As Mike says, of course, the key is to drive civilized.

 

330 mi tank. thats above my 300 before I got tuned... and Im 40+whp more than that 300 w/ stock injectors. So 330mi per tank is about what I was getting before I switched to E85, when I was only about 20+whp more than stock tune/injectors. Now on E85 the pluses are that gas is cheaper and its more performance... Not bad, not bad at all...
PoPcorn PoWeR

 

Good to see that running E85 isn't a huge hit in fuel economy. Planning on getting tuned for E85 (and 93 octane) if Mynes comes down to South Florida.

 

E85 inherently reduces fuel economy, as its stoich ratio is significantly lower than gasoline [9.0:1 for ethanol versus 14.7:1 for gasoline].

The best way to improve fuel economy is to improve your aerodynamics, shift to a higher gear, and run low rolling resistance narrow tires. If you want to improve power and maintain fuel economy, improving volumetric efficiency will help that. A high flow cylinder head, low restriction airbox, ported supercharger, port-matched intake manifold, merge collector header and low restriction exhaust will all help VE, which means more torque, which means you can run at lower RPM and improve fuel economy. Reducing accessory drag will help system efficiency. This means adding a larger alternator pulley and removing the A/C. Things that won't help [in theory] are a camshaft or supercharger pulley.

Reducing weight from your driveline will help get power to the ground. A lightweight flywheel, lightweight brake setup, and light wheels and tires will help too.

Cheers,
Ryan

 

Awesome input +1

After some more mods I am expecting to be sitting around 250-280 mi per tank

 

Sush, let's try another tank to see what kind of fuel economy you get on the 2nd tank... pls log your miles so we can gather the data and compare them to mine Popcorn power is fun

 

kapps, Mini's from the factory tends to run in the 10.5:1 AFR (mid to high 10's). On pump gas, we tune our cars to around 11.1-11.5 AFR depending on 91/93 octane. On E85, i'm at the 11.9-12.1 AFR.

Running in the 12.8:1 AFR is a little lean and should be avoided.

Just my 2 cents.

 

BOOOOOOM


...on PFI boosted setups like the R53 MCS we add fuel to add chemical quench to the combustion process, typcally by 1.0:1 [thus the targets for the R53 are typically 11.8:1 to 12.2:1 pre-cat]. Traditionally on n/a setups, 12.8:1 to 13.2:1 on 100% gasoline is peak torque, however that shifts to 12.3:1 to 12.8:1 on E10, and down around 8:1 [0.82-ish lambda] on E85. Why would you target a leaner than stoich AFR with E85?

Source

Regards,
Ryan

 

ROFLMAO.................I'm dying to hear this answer

 

You're a tuner, care to give your answer ?

 

why do I need to educate my competition...... you obviously DON'T know how to use your own equipment

 

I love it when you answer, I was thinking the samething

 

@the last 4 posts

 

nice to see amatuer hr is over with Mike and now we bring in the 2nd team for some chip shots.......

keep firing away... and read up some more on how a wideband works

 

this will satisfy for awhile

 

Trust me when I say, that to everyone involved in this thread outside you guys this is definitely facepalm territory.

On topic: My vote for performance and MPG gains has to go to removing all of the weight you can. If you have the opportunity ditch the rear seats, those are a bit on the heavy side.

 

I know I made my own. Ok back on topic .