# Fuel consumption with turboes???



## dburone (Apr 2, 2004)

You guys that swaped on turbos to you NA engines, did you se your fuel economy afected much???


----------



## chimmike (Oct 17, 2002)

it drops, hahahaha


----------



## NotAnotherHonda (Aug 7, 2003)

if you keep your egr on, it helps alot


----------



## chimmike (Oct 17, 2002)

egr doesn't have anything to do with fuel consumption, egr is simply emissions control equipment.


----------



## NotAnotherHonda (Aug 7, 2003)

chimmike said:


> egr doesn't have anything to do with fuel consumption, egr is simply emissions control equipment.



thats not what i heard at all. james has his egr and says he still gets 30mpg...i dont get that, and we basically have the same thing-injector and ecu wise


----------



## chimmike (Oct 17, 2002)

well you know yourself you installed the injectors wrong.

I eliminated EGR on my car and still got 25-30mph when it was tuned and I wasn't screwing with it.

heh, now that I have my wideband O2 setup...I can re-tune anytime I need


----------



## lshadoff (Nov 26, 2002)

dburone said:


> You guys that swaped on turbos to you NA engines, did you se your fuel economy afected much???


Before I turboed the car, I had all the bolt-ons (Header, JWT S2 cams, CAI, GReddy cat-back, JWT ECU). I was getting 26-28mpg highway.

I installed the turbo (HotShot T3, 370 injectors, stock MAF, JWT turbo ECU, same cams and exhaust) and was getting 29-31mpg highway. I replaced the GReddy cat-back with a 3" custom MagnaFlow cat-back, and the highway mileage is still 29-31mpg.

Lew


----------



## Chuck (Nov 19, 2003)

EGR drops your gas mileage down big time mike.. on my old GA, i installed some headers, adn eliminated the egr, and my gas mileage went down almost 100 miles per tank..


----------



## chimmike (Oct 17, 2002)

I never had that problem from removing the egr, lol.


----------



## GarrettSER (Apr 6, 2003)

I'm sorry, I don't think I caught the conclusion: do turbos (or forced induction in general) hurt the mileage or does it improve it?


----------



## James (Apr 29, 2002)

The only reason an EGR would hurt/help mileage is if the vacum line operating it is leaking!  

I've been driving slow lately just to see what kind of mileage I can hit. I just reached the 3/4 full tank line (1st line after full) and I'm on 110 miles. At half tank I can usually hit 180-??? but the last half of my tank I only get like 280-??? I say ??? because I don't know what the best I can do is, the first number is what I usually get. 

I do about 11 miles of traffic city driving to work and 15 miles to school so about 42 miles a day of traffic driving. I boost HARD once a day cuz I hit this one road here that is like a hiway and I love passing everyone, not racing just like the sound of it opening up.

usually 27-28mpg city. I did one drive to San Diego on highway most of the way and it seemed like it would hit 33+mpg if I went a whole tank on the highway.

Turbos don't determine the mileage... your foot does


----------



## spdracerUT (Jun 11, 2002)

gas mileage is relatively unaffected by putting on a turbo vs. NA. My mileage is similar assuming I don't get into boost too much 

EGR should have no affect on gas mileage either. It's just used to reduce NOx emissions. I had to get rid of EGR on my car when I went turbo and have had no probs or changes.


----------



## dburone (Apr 2, 2004)

I think it wont be affected if i drive normally, but if you step on it it will eat a lot more than when it was NA.


----------



## James (Apr 29, 2002)

You telling us or asking us? You started the thread you know?


----------



## dave_f (Dec 11, 2002)

gas milage goes down when you are on boost...crusing on the highway you are still pulling vaccum. but sometimes its hard to not be on boost because its so fun.
-dave


----------



## dburone (Apr 2, 2004)

James said:


> You telling us or asking us? You started the thread you know?


I usually have an idea but want to prove im correct, and ask what you guys think, if i dont ask how can i learn???


----------



## seximagtr (Feb 22, 2003)

hehe... if you drive semi-sanely, its comparable, i got 120 miles on my last tank... got b00st?


----------



## squeezinSE (Nov 15, 2002)

seximagtr said:


> hehe... if you drive semi-sanely, its comparable, i got 120 miles on my last tank... got b00st?


See I'm glad I'm not the only one...I get average 220ish miles to a tank between city and highway driving. Get's expensive especially since you have to use the expensive shit


----------



## James (Apr 29, 2002)

dburone said:


> I usually have an idea but want to prove im correct, and ask what you guys think, if i dont ask how can i learn???


I meant why did you post a thread and then come back on like 15 posts later and answer your own question. Next time you are trying to figure something out, do a bit of searching instead of posting a new thread.


----------



## Chuck (Nov 19, 2003)

Yeah, on my RB20det, as im cruisin around not boosting.. im getting 21-city 27-hwy.. While boosting alot... 15-city, 15 hwy.


----------



## hazar_ser (Feb 17, 2003)

squeezinSE said:


> See I'm glad I'm not the only one...I get average 220ish miles to a tank between city and highway driving. Get's expensive especially since you have to use the expensive shit


Yup, same here basically Im getting between 240-280 highway and city driving.


----------



## James (Apr 29, 2002)

Just now hit half tank and I'm at 190.


----------



## myoung (Apr 15, 2002)

I've very rarely ever gotten less than 300 a tank... even after turbo.. only on a few occasions when I was really boosting a lot.. and I mean a lot. If you get less than 300 on a GA16 you have some other problems. 

I of course don't run 20 psi to go to the store or race from one stop light to the next..


----------



## NotAnotherHonda (Aug 7, 2003)

i get about 225-240 mpg's..with no ac, and at 0 psi (thanks to cruise control on the highway).......i guess its my egr, or lack of?


----------



## James (Apr 29, 2002)

myoung said:


> I've very rarely ever gotten less than 300 a tank... even after turbo.. only on a few occasions when I was really boosting a lot.. and I mean a lot. If you get less than 300 on a GA16 you have some other problems.
> 
> I of course don't run 20 psi to go to the store or race from one stop light to the next..


i can hit 300 but I run dangerously close to empty. I usually have 1.25 gallon left in the tank on refill. Are you hitting 300 on empty?


----------



## Zen31ZR (Mar 24, 2004)

Just to clarify on the EGR bit , it's only used to reduce NOx emissions and part throttle knock when cruising. The EGR is only open at cruising speed , and is not open at idle or at WOT. In fact , if it were stuck open , the car would not idle.....  

As far as the fuel mileage with turbos bit , most turbo cars actually get _BETTER_ fuel mileage than NA cars , this is because of the lower compression ratio. Swapping a turbo onto a normally NA car is not part of this equation however , because of the _higher_ compression ratio. But turbo's won't generally make your mileage worse unless you boost on them a lot. That being said , I get a typical 12 mpg in town when boosting all the time.  If I turn the boost down or just don't get on it , I get up to around 30 mpg on the VG30ET.


----------



## myoung (Apr 15, 2002)

James said:


> i can hit 300 but I run dangerously close to empty. I usually have 1.25 gallon left in the tank on refill. Are you hitting 300 on empty?


nope.. highway is even better.. I used to drive from So Cal.. OC beach area to Vegas and still have well over a 1/4 tank left.. that's at least 250+ miles

I do normal maintainance stuff a lot sooner than normal.. clean the throttle body every other time I change the oil.. spark plugs every 10k or so, always run Super gas..... etc etc... ::shrug:: maybe its just those crazyyyy 98 200SX's....lol


----------



## James (Apr 29, 2002)

Could be man... and it could be you're lying out your ass!  

I think I need to adjust the valve lash... that seems like what is causing idle problems as well. I'll just do it when I get the cams...


----------



## squeezinSE (Nov 15, 2002)

There also needs to be distinguishing between those that have GA's and those with SR's.


----------



## Chuck (Nov 19, 2003)

god.. on my GA, i drove from houston to austin, and back, and had a 1/4 of a tank left.. thats what.. 400 miles


----------



## Chillboy (Oct 8, 2003)

Man if I get over 250 KMS to a tank in my turbo Spec I'm happy. It uses more than my van with a 5.9L.


----------



## AznVirus (May 8, 2002)

i can usually hit 300-350 on a full tank with mixed driving. i can say i boost a good amount a day, but not like i have a lead foot. even with spirited driving i can always hit the 300 mark not a problem.

i do believe our fuel tank sensor is pretty screwy. sometimes it looks like your gonna get 400 for full tank, but then drops a significant amount. i usually fill up at a 1/4 tank though.


----------



## 1810 (Aug 17, 2003)

Gas goes down if your halling your ass around. Like the person on top said its hard not to boost when you know you have the kind of power underneath your ass.


----------



## asleepz (Feb 24, 2004)

When I haul ass from stop light to stop light I get around 6-8 MPG regular city driving is abou 15 and highway is about 25-28. (Stock 87 300ZXT)


----------



## dange (Aug 23, 2004)

yeah as said before a turbo will increase gas milage...but only if drivin normal, if you start driving it like you stole it, its going to reduce mpg, a good trick is to try and keep the gas pedal no more than half way in if your trying to save gas


----------



## dburone (Apr 2, 2004)

Why do you say "turbo will increase gas milage" ? Because of it increasing the compression ?


----------



## chimmike (Oct 17, 2002)

turbo won't increase gas mileage........


----------



## dange (Aug 23, 2004)

The reason I say that a turbo will increase mpg is that with a turbo your making more power which makes the engine have to work a lot less, and the rule of thumb is that anything that can make an engine work less to acheve the same amount of power will save milage.

Now this will just be a scenario most numbers will be picked from the air but the principal is the same:

When I drive my nissan pickup on the freeway I average about 80 mph, between drag from air and drag from the ground it requires me to go approx 2500 rpm in 4 th gear (overdrive). Now from what I remember at 2500rpm my ka24e makes approx 40-50 horses so without getting technical and proving things im going to say we can safely assume it requires me approx 45 horses to stay at 80mph
Now on a turbo on average at freeway crusing speeds is constantly pushing boost,
Thereby providing my engine more air per revolution vs. my na engine,

Now everyone that knows anything about engines knows denser air= bigger boom which is why you do any mods that affect air will provide better mpg for instance the exhaust
You ad a flow master muffler which provides more airflow and less backpressure a flow master is proven to give 1-5 more mpg than stock why? Because your engine is making more power for the same amount of work!

Now back to the turbo, since your taking in more air per revolution thereby allowing you to make more power per revolution while boosted your horsepower has just gone up.
So theoretically before you were making 45 horses at approx 2500 rpm and due to this new power output you may be making 45 horses at 2000 rpm 
So due to this and all these numbers are true I can now cruise 80mph at 2000 rpm which means my engine now needs to spin and work a little-less-than-a-quarter less strenuously than it had to before.
Now before you say that more air requires more fuel, and etc I realize this, but the increased fuel consumption is still less than that of having to work 150% harder

So in ideal situations it will increase mpg, but who the hell is going to drive a car easier than before when they have a turbo


----------



## chimmike (Oct 17, 2002)

not really, you see, the only time a turbo makes more power is when 50%+ throttle is being used, which in turn requires a lot more fuel to match up with the air (while under boost) and that does not increase mileage.

If you were to stay out of boost all together, that's the best mileage you'd get, but it wouldn't be _better_ than before turbo.


----------



## INX2C (May 31, 2003)

It's really pretty easy to figure out engine modifications on fuel economy.

An engine is nothing more than a big air pump. 
Pump air in, mix with fuel, burn.......zoom. More air/fuel = more zoom. Simple.

The energy that moves your car forward comes from the gas tank. Period.

Doesn't mater if you speed up with a huge v8 or a 25 psi boost 1.6 liter. More go means more go-go juice. 

The huge advantage to boosted 4-bangers is the fact that you _can_ stay off the throttle and just sip the fuel.


----------

