17 MPG dont make sense
Thread Starter
Driver
Joined: Dec 2023
Posts: 50
Likes: 34
From: Canada
17 MPG dont make sense
Lexus said GX 550 gets 17 MPG, but it dosent make sense. The LX 600 uses same engine with higher 409 HP gets 17/22, 19 MPG combined, the GX has detuned 349HP, but only gets 17 MPG? Anyone know whats going on?
Thread Starter
Driver
Joined: Dec 2023
Posts: 50
Likes: 34
From: Canada
Thread Starter
Driver
Joined: Dec 2023
Posts: 50
Likes: 34
From: Canada
Last edited by jironman; Dec 8, 2023 at 10:13 AM.
Intermediate
Joined: Jan 2020
Posts: 282
Likes: 130
From: UT
Detuning the engine doesn't make it more efficient. Thats not how it works. The torque curves on the two motors are 100% artificially set within the PCM and the HP difference is a matter of changing a few numbers in the tuning. The only time the GX engine would use less fuel is if both are at WOT and the LX is using all of that 409 hp while the GX is limited to 349. The engines are physically the same and will operate the same when producing the same power/torque.
Take a look at the Tundra. They don't differentiate between the detuned SR trim with 358hp/406 tq and the SR5 and higher trims with 389hp/479tq because its all in the tuning. If both engines are producing 200 ft-lbs or torque at 2000 rpm, they will both be operating exactly the same and using the same amount of fuel.
EPA tests arn't running the trucks at WOT.
Take a look at the Tundra. They don't differentiate between the detuned SR trim with 358hp/406 tq and the SR5 and higher trims with 389hp/479tq because its all in the tuning. If both engines are producing 200 ft-lbs or torque at 2000 rpm, they will both be operating exactly the same and using the same amount of fuel.
EPA tests arn't running the trucks at WOT.
Last edited by skrypj; Dec 8, 2023 at 11:50 AM.
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Thread Starter
Driver
Joined: Dec 2023
Posts: 50
Likes: 34
From: Canada
1st Gear
Joined: Jan 2024
Posts: 1
Likes: 0
From: SK
Detuning the engine doesn't make it more efficient. Thats not how it works. The torque curves on the two motors are 100% artificially set within the PCM and the HP difference is a matter of changing a few numbers in the tuning. The only time the GX engine would use less fuel is if both are at WOT and the LX is using all of that 409 hp while the GX is limited to 349. The engines are physically the same and will operate the same when producing the same power/torque.
Take a look at the Tundra. They don't differentiate between the detuned SR trim with 358hp/406 tq and the SR5 and higher trims with 389hp/479tq because its all in the tuning. If both engines are producing 200 ft-lbs or torque at 2000 rpm, they will both be operating exactly the same and using the same amount of fuel.
EPA tests arn't running the trucks at WOT.
Take a look at the Tundra. They don't differentiate between the detuned SR trim with 358hp/406 tq and the SR5 and higher trims with 389hp/479tq because its all in the tuning. If both engines are producing 200 ft-lbs or torque at 2000 rpm, they will both be operating exactly the same and using the same amount of fuel.
EPA tests arn't running the trucks at WOT.
New to Lexus, so excuse me for ignorance. If the mech is the same on the LX / GX, is it possible to load the LX fuel/air map into the GX and safely drive around with 409 hp?
Rookie
Joined: Feb 2016
Posts: 40
Likes: 23
From: PA
One of the reviewers on YT(Toyota Jeff), flipped through the handouts they gave the reviewers in Tucson in preparation for the Feb 1 driving reveals. All of the spec sheets said 15/21/17 for MPG, so average fuel economy is 17 MPG regardless of trim.
Pit Crew
Joined: Feb 2010
Posts: 174
Likes: 4
From: West Palm Beach
5 degrees better approach than previous GX - this hurts MPG
smaller turbos so they spool faster for off-road response - this hurts MPG.
It's clear they balanced compromises well to still obtain better MPG than previous GX.
smaller turbos so they spool faster for off-road response - this hurts MPG.
It's clear they balanced compromises well to still obtain better MPG than previous GX.
Intermediate
Joined: Aug 2021
Posts: 489
Likes: 226
From: NE
Originally Posted by tsslaporte;[url=tel:11661344
11661344[/url]]5 degrees better approach than previous GX - this hurts MPG
smaller turbos so they spool faster for off-road response - this hurts MPG.
It's clear they balanced compromises well to still obtain better MPG than previous GX.
smaller turbos so they spool faster for off-road response - this hurts MPG.
It's clear they balanced compromises well to still obtain better MPG than previous GX.
Most of the time I’m in the 20-21mpg range.
