Cruising RPM?

darnell7654 · 11-22-2011, 05:25 PM

I recently bought an '89 Supra, very nice little ride but I have no history on it at all. I have the automatic overdrive transmission, non turbo engine. At 70 mph the tach is showing about 2850 rpm. That seems rather high to me. From a dead stop the transmission shifts four times and is solid. Fuel mileage is normal in the 20 to 24 range. The VIN shows 372 for the rear axle. I'm curious as to what is considered normal RPMs a 70 for a similar Supra. My guess is someone changed out the rear end to get more low end but as I said, I have no history to work with. Thanks

cre · 12-27-2011, 07:53 PM

You posted this in the wrong section. I've moved it to the MKIII forum.

No, that's about right. The N/A's all came with a 4.30:1 end gear where the GTE models came with a 3.91 or a 3.73 (pre89 models and 89+ models, repectively). The 3.91 end gear cruises at about 2720 at 70MPH.

If you want better mileage you may swap in a taller end gear from a GTE model but your speedometer and odometer will be off. The speedo driven gear from the corresponding A340E should fit though and correct the offset. (W58 and R154 gears are not interchangeable though) You will lose some acceleration but it's not a huge difference when just swapping to a 3.91... the 3.73 makes a much bigger difference. If you do not have LSD you'll need to swap the entire differential.

darnell7654 · 12-30-2011, 01:40 AM

Thanks for the info, I did manage to track it all down on line. This is a 4:30 rear end. Dang fun and doing 23 mpg highway so pretty pleased.

11-22-2011, 05:25 PM	#1
darnell7654 Stock Join Date: Nov 2011 Location: Mt. Pleasant, TX Posts: 4	Cruising RPM? I recently bought an '89 Supra, very nice little ride but I have no history on it at all. I have the automatic overdrive transmission, non turbo engine. At 70 mph the tach is showing about 2850 rpm. That seems rather high to me. From a dead stop the transmission shifts four times and is solid. Fuel mileage is normal in the 20 to 24 range. The VIN shows 372 for the rear axle. I'm curious as to what is considered normal RPMs a 70 for a similar Supra. My guess is someone changed out the rear end to get more low end but as I said, I have no history to work with. Thanks

12-27-2011, 07:53 PM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	You posted this in the wrong section. I've moved it to the MKIII forum. No, that's about right. The N/A's all came with a 4.30:1 end gear where the GTE models came with a 3.91 or a 3.73 (pre89 models and 89+ models, repectively). The 3.91 end gear cruises at about 2720 at 70MPH. If you want better mileage you may swap in a taller end gear from a GTE model but your speedometer and odometer will be off. The speedo driven gear from the corresponding A340E should fit though and correct the offset. (W58 and R154 gears are not interchangeable though) You will lose some acceleration but it's not a huge difference when just swapping to a 3.91... the 3.73 makes a much bigger difference. If you do not have LSD you'll need to swap the entire differential. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

12-30-2011, 01:40 AM	#3
darnell7654 Stock Join Date: Nov 2011 Location: Mt. Pleasant, TX Posts: 4	Thanks for the info, I did manage to track it all down on line. This is a 4:30 rear end. Dang fun and doing 23 mpg highway so pretty pleased.