and does it eat up more gas while not in use?

 

Well if it is not in use, it doesn't burn up any gas.

 

If you are cruising no, but if u are putting load on the car then yes.

 

On the STS website they claim there kit gives cars a 2-3mpg increase in fuel economy. This company makes the rear mounted turbo kits.


Now if you are pushing 15lbs of boost you need to increase fuel to make the air to fuel ratio correct. So you will use more fuel.

In my opinion a turbo will not eat more gas because you are just forcing more air into the engine. I have read that a turbo just makes an engine more efficient.

 

it makes an engine more efficient when cruising. like example when you're on the freeway. now if you're just boosting for the hell of it, yea its gonna eat more gas.

 

Yes it will. You can't just force more air into an engine without the proper amount of fuel to combine it with. Too much air and not enough fuel is no bueno. That's why most turbo KITS on the market come with larger fuel injectors to accomodate the setup.

 

You thought I'd let this one go and not chime in! Ha....Anyway, alot depends on the driver and alot depends on the tune of the fuel mapping. I've gone on the highway and set cruise control and my A/F gauge is 14.7 to 15 on level which is ideal for low load cruising and I would get 24 to 26mpg at 70mph roughly. Mixed driving I usually average bout 17. I've gotten as low as 12mpg on a tank. But mostly driver because most tuners I talk to say a car is either tuned or not tuned. That is the response I got when I said tune my car for safety or conservatively and not aggressive with ignition or fueling. If they tune it on the lean side, which would be not a good idea for engine longevity, you may see slightly better fuel economy.

My turbo may be on the larger side when compared with the greddy's or turbo extreme or some but a promise of greater fuel economy is a tall order considering you may need to install a high flow fuel pump and or larger injectors. And the higher back pressure created by the turbo won't help matters with the fuel economy. And as someone above me already stated, the dude that says all you are doing is pushing more air in the engine should do some homework because that is exactly the reason that would cause lower fuel economy because to keep the motor safe you MUST increase the amount of fuel sent to the engine after force feeding air to the cylinders.


Turbo's also eat up more tires and clutches HA!

 

She's cheating on y... oh wait.

 

I was surprised that you were not the first to respond to this thread.

 

Just curious, whats your AFR in boost?

 

double post

 

It's about 13 just when boost starts to build at about 4k, then into the low 12's at midrange in boost then bottoms out at around 11 from 6k to 8500rpms

 

^how many pounds are you boosting?

 

6 and up to 10ish. Between 10 and 11 takes me to 400 to 420 at the wheels so I try to stay below that

 

^i was talking to chargedsi before and he was telling me that 10 psi on stock internals is pushing it because of the rings.

 

AFR is healthy. I think the k20 makes the most power when AFR is in the 13's, for n/a at least. Very nice!

 

Yeah probly good to stay below 10psi. But I don't think it's about the psi rather than power because not all setups yield the same power results. I have noticed that smaller turbos at 10 or 12 psi only make 300 or so hp. But high psi does make for high cylinder pressures so I dunno. I've heard on a good tune 400whp is ok AJP reccommends staying below 420whp. So I like the car at 350whp and anymore than that and you don't get traction til 3rd gear.

And yeah A/F's in the 13's almost always make good power but you don't want to be running a boosted car in the 13's on your air fuel ratio if you want it to last very long. Turbo tuners usually stick to the low 12's if not even low 11's. If it's too lean the exhaust gas temps get to high and then you are in trouble

 

Yeah it depends on the size of the turbo as well. A bigger turbo is going to be forcing more air into the motor than a smaller turbo will be at the same PSI level. Correct me if I'm wrong guys, but psi refers to the amount of force not necessarily the volume of air being forced. So bigger turbo = more power but also comes with more lag.

Back to the OP a turbo set-up is going to yield you less mpg. Like said above the more air the more fuel is needed to compensate. My STi would pull down about 25mpg mainly freeway never hitting boost and if I got on it a couple times my average mpg dropped drastically.

 

lulx turrrbo 101

class in session

 

Depends on how you drive, your tune.

 

lmfao well cruisin around wit 1000cc will prob do it.

 

Pencils down, eyes closed.

 

if youre worried about fuel economy, you shouldnt be boosting. period.

 

Someone get me some f**kin popcorn!