Turbo and mpg
 

Hi!

First of all I would like to say that I have read and searched a lot this week, but I haven't found answers to all of my question, so I'm asking now... I've never installed a turbo before, or even tried a car with custom turbo setup, so I might ask stupid questions, but please dont flame, I'll try to avoid "how many psi on stock internals" :)

I'm running a recently rebuilt D16Z6 with stock internals, and what I'm aiming for is a fun, reliable daily driver. 160-170whp should be enough to put a smile on mye face. However, gas is pricey in my homecountry, so fuel economy is quite important. Being a daily driver, it must be able to cruise at 60-70mph without having to pull over at every gas station.

So if I'm ending up using a T25, which spools up around 2500rpm at WOT (just as an example). Will this thing spool up at 2500rpm when I'm at partial throttle also, and build boost when I'm cruising at the highway? If this is true, does that mean if I'm going to keep an acceptable mpg I need a bigass turbo which doesnt spool up before 3500-4000? I will be using bigger injectors and tune with crome, btw.

What kind of mpg do you guys with small turbo's get on the freeway?

Re: Turbo and mpg
 

according to alot of people on here.. i think everyone.. miles per gallon increased after they boosted the car.. it requires good tuning.. obviously if you run on a basemap and your running rich.. miles per gallon is gonna go to ----.

https://www.homemadeturbo.com/forum/...?topic=52565.0

Re: Turbo and mpg
 

You won't build boost at part throttle at all, and with a decent part throttle tune or even just an fmu you won't get bad gas mileage-- I drove around without fuel management and stock injectors for 2 weeks without ever hitting boost. As long as you don't have a heavy foot all the time your gas mileage will not get worse-- I have a boosted b18b in my civic and I still get 30mpg even with rape.

Re: Turbo and mpg
 

OK, thanks!

I thought I read somewhere that turbo's builds the same boost in WOT and partial throttle, but it doesnt sound logical. I must have been dreaming or something :)

Re: Turbo and mpg
 

^^depends on the turbo

Re: Turbo and mpg
 

Really? What parts of the turbo affects that, and what turbo's should I stay away from to avoid it?

Re: Turbo and mpg
 

The manifold is obviously going to effect spool time along with your charge piping. Best bet is to stay away from a small turbo because a small turbo will build boost at lower rpms.

Re: Turbo and mpg
 

Yup. More low-end torque = more fuel used.

Re: Turbo and mpg
 

What??? Nothing from Boost, Whitey or Johnny on this topic? Slow day...?

Re: Turbo and mpg
 

oh johnny will be in here preaching about big motors getting great gas mileage ^-^

Re: Turbo and mpg
 

actually doing highway pulls uses more gas than going from a stop

Re: Turbo and mpg
 

ya but the reason i got a small turbo is because once i step on it i want it to go...

Re: Turbo and mpg
 

wtf u think a big turbo does
you must think turbo lag bogs you down

Re: Turbo and mpg
 

under regular driving condition.
smaller turbo spool up easier = lower mpg
bigger turbo spool up later = better mpg

better tune = better mpg
easier driving = better mpg

i had a d16 with t3/04e and i net 40mpg the most.
when i drive the ---- out of it i net about 25mpg.

Once i raced with a friend for about 20 minutes on the freeway going 130 + and actually saw the gas gauge moved almost 1/4 of a tank :X

Re: Turbo and mpg
 

i had a mitsu 14b on my d16z6 and on the way back from the hmt camping trip managed 41mpg average for about 1/2 the drive. Usually freeway mileage was about 35mpg.

Re: Turbo and mpg
 

OK, thanks!

Guess I'll stick to my plan and use either a 14b or a t3 .42/.48, and learn how to tune :)

Re: Turbo and mpg
 

on my street tuned y8 with a .42/.48 i was averaging 30 mpg on every tank, and under normal driving too, if i really short shifted i could squeak out another 2 mpg. NA, best i could ever manage was 36. It's all in the tune and how you drive it