RB25DET terrible mpg

[Blitanicle99]

This is a strange post.

The S14 I acquired has an RB25DET, SAFC, front mount, boost controller and exhaust. Puts out 317 to the wheels. Pretty nice power band.

It gets like 200 miles per tank if your easy on it. And like 110 your NOT easy on it.

Could this be a tuning issue? Its on a stock turbo. I know with more air comes more fuel, but would a turbo upgrade help this out?

...Suggestions...?

[quicksix]

running a little rich?

[Blitanicle99]

Dave Ciporkin tuned it last time, so I dunno. I would assume rich, but I don't know whats normal on these motors.

[OWN3R]

mine drinks a good bit and mines basicly stock

[AllTheDude]

my sr20det sucks it down too. walbro 255 for the gas mileage loss. I get way less than 200 out of a tank. doesn't help that its barely a 10 gallon tank.

[Blitanicle99]

Damn, theres no way to get it to better mileage and keep reasonable power?

Like 25ish on the highway and maybe 15-16 around town? Sorta like a low geared V8 F body?

[AnthonyF]

rich = safe

But also makes u burn gas like a pig. This is what I would do: new plugs, new fuel filter, new tune.

-Ant.

[AnthonyF]

Damn, theres no way to get it to better mileage and keep reasonable power?

Like 25ish on the highway and maybe 15-16 around town? Sorta like a low geared V8 F body?

My truck only gets 19mpg. My mustang only got 18 w/ boost. With stock engine I could touch 30.

-Ant.

[Atlblkz06]

Exactly how big is the tank?

[Frög]

holy shit! 110 m/tank!?!?!?!

[Blitanicle99]

Either 12 or 14 gallons I forget.

And yes 110 miles to the tank. I thought the plugs fouled up and it wouldn't start. Nope, 110 miles after I filled up I managed to waste the tank in like 3 hours?

[HypnoToad]

holy shit 110miles.....wow,think ill stick to domestics i get almost 350 miles out of my V8

[Blitanicle99]

^

And you'll keep getting lapped.

[HypnoToad]

^

And you'll keep getting lapped.

lol,id hope so car is stock.

[.blank cd]

This is a strange post.

The S14 I acquired has an RB25DET, SAFC, front mount, boost controller and exhaust. Puts out 317 to the wheels. Pretty nice power band.

It gets like 200 miles per tank if your easy on it. And like 110 your NOT easy on it.

Could this be a tuning issue? Its on a stock turbo. I know with more air comes more fuel, but would a turbo upgrade help this out?

...Suggestions...?
On a real note, are you serious? what do you expect from a boosted 6 cylinder? a super-green 35 mpg? Get a daily driver homes

[Blitanicle99]

On a real note, are you serious? what do you expect from a boosted 6 cylinder? a super-green 35 mpg? Get a daily driver homes

No I don't expect the gas mileage of a civic.

Its a turbo 2 liter. And after reading up on Nico forums, some guys are getting 28 if your not on it. The average is about 23-25 on the highway if tuned right.



Oh and what dos a boosted 6cylinder have to do with it? My 400 hp turbo 8 cylinder gets 21.6 on the highway cruising at 76 mph.

[Kaiser]

holy shit 110miles.....wow,think ill stick to domestics i get almost 350 miles out of my V8


And you probably have a 20, 22, or 25 gallon tank. O_o



Its a turbo 2 liter. And after reading up on Nico forums, some guys are getting 28 if your not on it. The average is about 23-25 on the highway if tuned right.



HybridZ guys use RB20's mostly for low-power daily drivers. Most of them can hit 30mpg highway, but that's out of a 2000/2400lb car fully loaded. Your WOT tune seems super rich, but if you're putting down 300whp then you might be over-stressing the setup to get that kind of power. That much gas might be necessary for that kind of setup with stock turbo. To be honest I'd get it retuned with 300hp as the goal, and if that still gives shitty power, get it retuned to be leaner where you can see what gas mileage is lower down. After that, I'd go with the basics to get more efficiency out of the motor.

This is all after you've done the dumb normal stuff. Plugs/wires/filters both air and fuel and so on.

Edit: Durr. Wait. I'm an idiot. You said it had an RB25DET, yet then you said it was a two-liter Turbo, is it an RB20DET or RB25DET? If you're only getting 300 to the wheels and terrible gas mileage out of an RB25DET you need to have that looked at. Something is bad.

[HypnoToad]

And you probably have a 20, 22, or 25 gallon tank. O_o



12.5;)

[Kaiser]

12.5;)

What car? My 4 cylinder has a bigger tank than that and doesn't get 350 to a tank.


Edit: And that's 28+mpg every gallon from absolutely full to the last damn drop. Pretty impressive for a V8.

[HypnoToad]

What car? My 4 cylinder has a bigger tank than that and doesn't get 350 to a tank.


Edit: And that's 28+mpg every gallon from absolutely full to the last damn drop. Pretty impressive for a V8.

well since ive owned it,id let it go all the way below E and most ive ever put in is 12.5gallons.

91 Camaro RS 305TBI/700r4 with 2.73 gear

[Blitanicle99]

Hmm, ran into Dave @ Lethal Injection last night and we talked it over. Might be an O2 sensor, it will take some tweaking.

[Kaiser]

well since ive owned it,id let it go all the way below E and most ive ever put in is 12.5gallons.

91 Camaro RS 305TBI/700r4 with 2.73 gear


Wow, well, I cheat a bit. My 4 Cylinder is actually an A4 Quattro turbo, so. Only gets around 22-23 average, not that much bigger a tank than yours either.