t2d2

iTrader: (8)

It only jumped out at me as odd because mine is so mellow on the highway, just purring along like a happy cat. (Gotta get in that "big cat" reference!)

KahnBB6

iTrader: (5)

^^ 1UZ V8's are one of the best long haul cruising engines.

I'm not sure what the rear ratio is on a 1998-2000 LS400 but I've driven one of those a lot and revs on the highway at 70mph were a lot less than 2800. More like 2100-2200 at most if I am recalling accurately.

Matguy, good luck getting your SC400 back together!

matguy

Yup, you're right. I don't know what I was thinking.




My math puts 70MPH at about 2250RPM. I still think it could use some lowering, but not as bad as I was thinking.

And thanks for the well wishes. Went back together OK.

KahnBB6

iTrader: (5)

Good news, then!

I don't think there is a lower ratio than 3.266:1 for the 200mm diff. I can't imagine it being much lower with only five gears in the 98-00 cars.

matguy

Oh, and this morning I noticed that I was wrong yesterday. I wasn't noticing the hash marks on the tach were 1/4 of 1000 and not 1/10. So, at 65MPH it was around 2250 (not 2100) which puts 70MPH just over 2400RPM, which it was this morning.

KahnBB6

iTrader: (5)

Hmm. The final drive in a 98-00 LS400 must be lower than the 3.26 in that case. I didn't look closely at your picture that evening either.

It would make sense that the SC400 with the same drivetrain would have a more aggressive FD though.

t2d2

iTrader: (8)

^ I've read that the LS400 is geared for better highway economy.

matguy

Hmmm... *scratches chin*

If the transmission has a wider range of ratios... well, to be realistic, it's not like I'm going to do a tranny swap just to get slightly better mileage. I'll just complain about it from time to time.

KahnBB6

iTrader: (5)

Well both the '98-2000 LS400 and '98-2000 SC400 use the same version of the 1UZ and the same heavy duty version of the A650 5-speed automatic. It's probably just the ECU's and rear ends that account for the differences.