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Discussion Starter · #1 ·
It's about time i put a single into my supra and i wonder. How different does the MPG change from BPU to single? I am also planning on using something like a t78 or 74gtq with 750cc-950cc injectors. I'd like to hear some opinions before i go to the single.
 

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Daily driving, mine went up 4-5 mpg (city) because I'm never in boost like I was with seq twins. Getting on it often drinks the gas pretty quick.
 

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Shawn Davis
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This is a strange question...Your best MPG is when you're off boost, so what difference does it make what turbo you're running? When you're in boost, then the amount of gas you use is determined by the amount of power you're producing....
 

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Boost Junkie
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I don't really keep track of it around town, but with the MAF in place and a 67 I am able to get around 25mpg on the highway-at 75 to 80mph.

Steve
 

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I love sequentials!
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Do you think each motor has the same volumetric efficiency off of boost, when using different turbo set ups?

There are still factors such as back pressure, the amount of energy expended to move different size impellers and turbine wheels, etc etc. All of this plays into VE, which plays into gas mileage.



Ubermensch said:
This is a strange question...Your best MPG is when you're off boost, so what difference does it make what turbo you're running? When you're in boost, then the amount of gas you use is determined by the amount of power you're producing....
 

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Shawn Davis
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turbosupra said:
Do you think each motor has the same volumetric efficiency off of boost, when using different turbo set ups?

There are still factors such as back pressure, the amount of energy expended to move different size impellers and turbine wheels, etc etc. All of this plays into VE, which plays into gas mileage.
For a stock motor, yes I believe the volumetric efficiency is very similar. It's not the same, but I find it hard to believe that the difference would be large enough to see a measurable difference in fuel economy.
 

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Alpine Hardtopper
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turbosupra said:
Do you think each motor has the same volumetric efficiency off of boost, when using different turbo set ups?

There are still factors such as back pressure, the amount of energy expended to move different size impellers and turbine wheels, etc etc. All of this plays into VE, which plays into gas mileage.
True, except VE *shouldn't* mater that much. Lets say car #1 has a nicer intake and better VE through the turbo than car #2. In order to drive down the road at 40 mph, both Supras are going to need the same power output (assuming same weight, similar tires, and comparable drivetrain losses). Car #1 will have the throttle closed *slightly* more than car #2 for that speed. But they'll both have the exact same airflow (and consequently fuel flow).

Backpressure can cause a decrease in fuel economy though. But I don't see any singles as having worse back pressure than the stock twins.

Either way, a Supra is going to get 12-15 mpg driving around town in most situations, and 20-25 mpg on the highway. And it *should* have high octane pump gas (at worst....some prefer race fuel).

It is possible to get slight increase in fuel economy around town after going single. With the twins in sequential mode, #1 comes on SO early...even if just cruising gently between stop lights. On a single it's a lot easier to keep from making boost unless you actually want it. And when you're not making boost you're not making as much power, and you're not drinking as much fuel.
 

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!black
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~20-22mpg average in my sc300. Usually cruise between 75-80 w/ ac blasting. I've just changed out my O2's and tranny flush. When I first got the car, avg'd 460miles per tank (20.5gal).

NA's burn just as much as turbos, hell I think even a little more. Maybe I can lean it out a bit on the low throttle with a SAFC :)
 

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SteelCitySupra said:
0.5-2mpg :) I'm not sure, I dont drive mine enough to calculate mpg... but im sure its pretty damn low.
word, i get 14psi per gallon :D
 

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Ex-hardtopper
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^^^ Same here, BL67, VPC/AFC, etc. Around town with spirited driving, ~15mpg. Haven't ever taken it on a long highway trip, so don't know what it would do just cruising.
 

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Discussion Starter · #13 ·
With those MPG's you guys are hitting on a single turbo, it makes me want that single turbo even more! :bigthumb:
 

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SC61 stock 550 fuel injectors 264 cams, vpc. 20mpg around town easy driving. Current with AEM 20mph but not tuned yet.
 

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Ex Supra Owner
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i get great gas mileage on my single. ten times better than when i was bpu also when im out racing or on the freeway doing some highway runs it seems to me that the gas gauge doesnt drop at all for the whole night of racing
 

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MadMaxx said:
~20-22mpg average in my sc300. Usually cruise between 75-80 w/ ac blasting. I've just changed out my O2's and tranny flush. When I first got the car, avg'd 460miles per tank (20.5gal).

NA's burn just as much as turbos, hell I think even a little more. Maybe I can lean it out a bit on the low throttle with a SAFC :)
are u crazy 460 miles per tank is amazing i barley get 300
 

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Old School
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MKIVdan said:
i get great gas mileage on my single. ten times better than when i was bpu also when im out racing or on the freeway doing some highway runs it seems to me that the gas gauge doesnt drop at all for the whole night of racing
Better work on that tune, Dan. My gas gauge goes up after every freeway pull.
 

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I get 24-28 when I'm cruising on the highway. I have my supra tuned on AEM and 800 rwhp With 1000cc injectors, Dual Supra fuel pumps, T88H Turbo, 4" Exhaust, etc.
 
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20 city 30-35 highway most of the increase in my gas mileage was with my standalone that accopminied my single turbo which allowed me to switch from maf to map so the venting of the bov rich problem is gone, running better air fuel ratios and timing.
 

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Ex Supra Owner
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Lagtime said:
Better work on that tune, Dan. My gas gauge goes up after every freeway pull.
That is awesome, i think its time to give J. Nenni another call! Chip, you should be the happiest guy in the world with the gas gauge rising after every pull!!!! On another note. If i have over a 1/2 tank of gas in my car gas doesnt burn anything under a 1/2 tank its getting wasted fast
 
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