3GSh vs 4GSh differences?
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From: IL
3GSh vs 4GSh differences?
I was digging around and realized the final drive (rear axle gearing) is 3.76 on the 3GSh and it is 3.27 on the 4GSh. The 3.27 was the 2GS4 rear gear and the 3.92 was the 2GS3 rear gear. So they just pulled the gears out of the parts bin. I think the LS/GS460 has a 2.92 gear (8 speed auto cars)
That might explain a few mpg difference. Its temping to try a swap and see how the car handles it. The 2GS reads vehicle speed from the ABS Sensors, so gear swaps are nothing to do, no calibration needed. I sort of wonder if the 3GSh is similar.
But a rear diff isn't expensive, so it is really tempting to see how mpg changes.
That might explain a few mpg difference. Its temping to try a swap and see how the car handles it. The 2GS reads vehicle speed from the ABS Sensors, so gear swaps are nothing to do, no calibration needed. I sort of wonder if the 3GSh is similar.
But a rear diff isn't expensive, so it is really tempting to see how mpg changes.
Last edited by RamAirRckt; Apr 2, 2020 at 12:11 PM. Reason: Correction 3.76 gear on 07-11 GS450h
Racer
Joined: Jan 2019
Posts: 1,349
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From: Sofia
The 4GS has an atkinson cycle engine - 2gr-fXe. X = fixed atkinson (late intake valve closing), K means on-demand. The atkinson cycle is the sole reason for the economy differences 
Toyota has used non-atkinson engines in a number of their hybrids - 3GS (2gr-fse), rx400h(3mz-fe), ls600h & 3rd-gen century (same cars - 2ur-fse), I think the first crown hybrid as well... perhaps a few more.
The 3GS hybrid in europe has the 3.266 gear - performance is practically on par with the 4GS (5.9 0-60mph stated, around 6.4 in practice, top speed around 270kph). We get bigger top speed (practically unusable outside of autobahns), worse acceleration and potential throttling issues when MG2 is in high hear and you're at the lowest speeds before it goes back to lower gear.
Don't change your gearing. If you want better economy - a swap to an - FXE miiiight work, but you'll have to spend some time on techinfo.toyota.com just to get a general idea on whether the hybrid ECU will interface with the 2GR-FXE engine ECU at all - and there's still a risk.
Keep in mind that the 2GR-FXE has two versions - for RWD cars (gs450h/crown(majesta)) it has dual injection, for FWD/simulated AWD (rx450h) it is port injection only.
Toyota has used non-atkinson engines in a number of their hybrids - 3GS (2gr-fse), rx400h(3mz-fe), ls600h & 3rd-gen century (same cars - 2ur-fse), I think the first crown hybrid as well... perhaps a few more.
The 3GS hybrid in europe has the 3.266 gear - performance is practically on par with the 4GS (5.9 0-60mph stated, around 6.4 in practice, top speed around 270kph). We get bigger top speed (practically unusable outside of autobahns), worse acceleration and potential throttling issues when MG2 is in high hear and you're at the lowest speeds before it goes back to lower gear.
Don't change your gearing. If you want better economy - a swap to an - FXE miiiight work, but you'll have to spend some time on techinfo.toyota.com just to get a general idea on whether the hybrid ECU will interface with the 2GR-FXE engine ECU at all - and there's still a risk.
Keep in mind that the 2GR-FXE has two versions - for RWD cars (gs450h/crown(majesta)) it has dual injection, for FWD/simulated AWD (rx450h) it is port injection only.
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