Is there someone here that changed the rear end gears in their F? I seem to be remembering that someone did and was wondering how big a difference it made slash what size gears they went with.



Thanks,
Kyle

 

my car has a 4.08 rear end swap. Done by Lexus of Dayton, before i bought the car from them. I recommend you contact Doug Greenup there (or through here), he has all the minute details, and can provide all you need.
I have driven no other F, and mine only already swapped, so cannot really opine too much on the difference..
i can tell you that first gear is very brief, and that when passing, etc the 50 to 80mph acceleration is insanely fast..

http://www.lexusfforum.com/forums/sh...light=fchampoh

 

ax did you ever run the car at the track and how miles have been put on the car since they were put in? Also what is the top speed now for the car and do you drive it hard like it is meant to be?

Thanks,
Kyle

 

I don't think swapping to 4.1 rear end is going to help much because our overall ratio is pretty short as it is. Just a waste of gas. With TC off, first gear already spins so on a street launch, there really shouldn't be much of an improvement 0-60 (any improvement is lost with an additional gear change). Now, with drag radials on a drag strip, we should see maybe a couple of tenths improvement? I'm just speculating here. A quicker 60' like 1.8 or even 1.7 seconds could really help the ET. I don't think top speed will really go up.

 

these might help even with street tires at the track...so im thinking not sure though

 

The theoretical top speed in each gear for an ISF with stock tire height is as follows (approx). The first number is the stock 2.94:1 gears, and the second is with 4.08:1 gears:

1st - 4.60:1 - 38 mph – 28 mph
2nd - 2.72:1 - 65 mph – 47 mph
3rd - 1.86:1 - 96 mph – 69 mph
4th - 1.46:1 - 122 mph – 88 mph
5th - 1.23:1 - 145 mph – 104 mph
6th - 1.00:1 - 179 mph – 129 mph
7th - 0.82:1 - 218 mph – 157 mph
8th - 0.69:1 - 259 mph – 186 mph

I imagine changing to 4.08 gears would make acceleration fun but cruising on the freeway much less enjoyable (much higher revs). Stock, the ISF cruises at 76 mph at 2000 rpms in 8th gear. With 4.08 gears it would only be doing 54 mph at 2000 rpms, or when cruising at 76 mph would be pulling 2800 rpms.

 

fyi- 60mph = 2150rpm in 8th
No, i have not taken her to the drag strip. Yes, i drive her like she likes it..
Have around 15K on her, no problems at all. average 20-21mph in "normal" driving.