Hey peeps, in no way a mechanic or mechanically minded ( yet )

I just recently got a 93 LS400 but the guy I got it off forgot to mention that the Speedo is off at high speeds 60kph +. It also rubs the fender slightly when going around a roundabout.

It’s has some really nice 20s on them and I don’t really want to change them,

What would be the process of adjusting the speedo ?

The back window switches and the passenger (sometimes) will not open the window, I’m assuming if it was the fuses the passenger side would not work at all.

I’ve owned a 90 celsior before and the acceleration on that car was significantly faster than this one. What would be some things to check up on and narrow down the problem ?

I’m currently looking after my father so don’t have the funds to pay someone to do it for me and I want to learn this car inside and out so want to do all the work myself.

thanks for any help you can give me

 

there's no process to adjust. the overall diameter of the tires are incorrect. 20s don't usually fit the UCF1x (first generation) LS400 without rubbing on a stock body car.

You need the correct sized (likely VERY low profile) tires to correct the speedo.

 

thanks mate.
If I install coil spacers would it give it enough lift that It wouldn’t rub ?

 

you asked for help...our moderator gave you help, and now you are trying to find away around his guidance.. ?? why ask for help??

 

having heavy 20" wheels also affect acceleration hence your feeling this one is slower. coil spacers will only band aid the solution and even throw off your alignment.
better to get right sized tires (lower profile) to get the right diameter the speedo is calibrated to, or find stock wheels/tires to begin with.

play around with this and use the "tire comparison" tab to see your speedo % error:
https://tiresize.com/calculator/

 

 

 

Wheel size doesn't affect acceleration, wheel/tire unsprung weight does.
Overall tire diameter does, though minutely.

AFAIK coil spacers aren't legal for rego in australia, but i'm a bit far removed. You could possibly fix the rub with them but you'll mess up your suspension geometry and will need an alignment, and will still likely see increased/abnormal tire wear.

 

You might be able to find someone who will swap wheels with you, maybe even scoring some $$$ out of the trade.

Regarding the lack of power, a soft-failing fuel pump might give you something like that. My '91 was running well, or so I thought, with just a few minor intermittent driveability issues. I finally isolated it to the fuel pump, replaced with a Denso (about $100, pretty easy DIY), and am back to burning rubber when I'm not careful.

Here's a post I made back when I was debugging these issues. It contains pretty detailed and quantitative debugging steps to help you avoid replacing things that don't need it. You do need a multimeter for those tests.
https://www.clublexus.com/forums/ls-...ml#post9777959

Good luck getting it all sorted out.