1JZGTE MPG Q's
 

I may do a 1JZGTE swap soon, just wondering what average Gas Milage is. Im currently getting 18-21 MPG in my 92 300 Auto. Also, would there be any functions I would lose? Such as AC, or PS ?

Planning on running the 1JZGTE stock, including stock exhaust.

You shouldn't lost anything when fitting the 1JZ in.

For the record my car does about 13L/100km in normal driving on 98RON fuel and about 8~9L/100km on the highway (cruise control on, aircon on, slightly oversized tyres and 3.5hr trip).

As long as I don't keep my foot in it, I get about 24 mpg on the freeway...slightly better than the 2JZ I had in there before. This is with the 5-speed. If I'm having fun with the throttle, around town I get about 17 mpg.

Both my PS and AC work after the swap.

translation: ~18mpg city, 25-29mpg highway on 93octane(crazy euros :p they have their own way of measuring octane and mpg)

Cool, I got 16 Highway, and 35 City??? Thanks for clarifying that. 24-29 highway is pretty bad ass. More reasons for the swap...

i managed like 35mpg once on highway, not really boosting
get like 20's any other time/place

my oxygen sensor probably needs to be replaced, but i get around 20 mpg on the highway and anywhere between 14 to 16 in the city with my 1jz and my car is a 5 speed. are you guys like always staying out of the boost?

not really, lol
maybe you have a vac leak.

Your speedometer has to be off, how did you calculate that? There's no way a SC is gonna hit 35 mpg, unless its dropped out of a plane.

i can get upwards of 30mpg going 75 not in boost. Driving around town in boost all the time, i get no less then 20. A bad o2 sensor will get you 16-18.

Yeah, never had to use the metric~imperial conversion so I didn't worry about changing it over.

Oh, and I'm in Australia :p

How can you say that if you boost, you get 20 mpg, yet someone with a bad O2 sensor will get 16-18? You're contradicting yourself...when in boost, the 1JZ ECU will completely ignore the O2 sensor output anyway and go dead rich. So unless you've got a standalone, you'd get worse gas mileage than a SC300 with a bad O2 sensor by driving around in boost. Nevermind the timing that gets pulled the moment you see boost...but I won't get into that.

Have you even hooked up a wideband and driven your SC around? I have...at cruising, I'm getting 14.6ish AFRs, indicating that the O2 is working within an acceptable range. And I get about 24 mpg. Maybe there's special gas in Florida. :) I'd bet your speedo is off.

I guess you never drove a 1JZ. You dont need to go WOT or anything else to make the ECU go into closed loop mode to run boost. The ECU doesnt instantly go closed loop at specified PSI.

Wow, you're really showing your lack of knowledge here. Lets get our terms correctly here first. "Closed loop" is when the ECU is relying on the O2 sensor to trim fuel delivery. "Open loop" is when the ECU is relying on internal maps SOLELY and ignoring the O2 sensor.

Okay now we've got the basics out of the way. The speed-density management scheme on the 1JZ is pretty simple and similar to other speed-density systems in use. When engine load (which to the ECU is RPM & MAP based) reaches a certain threshold, the engine will go from closed loop into open loop. With a turbocharged car you CANNOT run closed loop while in boost. The narrow-band O2 sensor that the 1JZ employs is incapable of being accurate at anything other than stoichiometric (that's 14.7 parts air to 1 part fuel). To put it simply...the moment your 1JZ is in boost, the ECU is no longer "listening" to the O2 sensor, and is relying on safe Toyota-quality fuel ratios to make sure that your 1JZ will provide years and years of trouble-free boosting.

So I say again, if you're getting 20 mpg while driving around in boost, another 1JZ will do the same. The O2 sensor isn't even part of the equation when boost is involved.

Since the 1JZ is in boost 90% of the time unless on the highway. Wow we dont even need an o2 sensor then right Mr. Toyota?