fastlex99

I got a 1999 Lexus LS400. Does any one know how to either raise or remove it to up the max speed of the car?

gmacrae

a greddy speed cut defender did the trick on my supra (180k cut), will be the same for these cars... what is the speed limited at in your car? I *think* mine isn't limited.

PureDrifter

iTrader: (10)

the USDM LS isn't really governed, we tend to top out ~155-158mph.

dfkd

Lexus says it's electronically limited at 149 here.

trukn1

Yeah, it says 149. We have had some reckless people here on the forums disprove that number and manage to push it to the absolute limit, topping out around the 155 mark.

https://www.clublexus.com/forums/ls4...-98-ls400.html

hobojoe

Pushed Mine at a course to 151.....

fastlex99

so what your saying is that 149 mph isnt true that the car can go faster than what they say it can?

PureDrifter

iTrader: (10)

yeah pretty much.

dfkd

In the video, at 150 the tach was around 5000 rpm so the car would be able to make another 25 - 30mph without a limiter before it hits redline; assuming it has the power for it.

PureDrifter

iTrader: (10)

not really, cars don't always keep accelerating all the way up to redline. most production cars will be drag limited before they run out of gear. what that means is basically at that speed the force of air pushing back against the car as it travels through it is eqal to the power the engine is putting out, so no acceleration occurs.

dfkd

That's what I meant when I said "assuming it has the power for it". The only way to beat drag at high speed is more power or lower Cd.

The Veyron can make it to about 150mph with only 250hp. It takes the other 750hp to do the other 100mph to its top speed. Most of that 750hp is used to beat drag.

However, I'm sure that the extra power that the vvti 1UZ puts out, together with the lower Cd of those models and the extra gear(s) (compared to the 1st gen which is already capable of making it to 150mph), should be enough to get quite a few more mph out of the car.

hobojoe

soo a bit off topic on this but since gen1's are not vvti what would be needed etc for forced induction to work correctly since its now what im looking into for the 6-9psi range just for the get up acceleration...

PureDrifter

iTrader: (10)

http://www.lextreme.com
http://www.v-eight.com

enjoy. everything you'll ever need. (except monies)

hobojoe

^^ human ls Bible

JBrady

1998-2000 USDM LS400s are limited to 149mph. This is not based on the speedometer display (which shows apx 5mph too high) but is measured by the computer. If you change tire size or gearing that will go up or down because the measurement the computer looks for appears to be based on RPM.

Actual tire size does vary slightly between brands for the same stated tire dimension such as the stock 225/60-16. If you run higher tire pressure they will be slightly larger in diameter. As the tread wears they will be slightly smaller. My guess on the 151mph given by Horta's GPS is brand new tires with peak rated inflation.

It is interesting that some believe that european cars had no limiter or a higher limiter and went faster than 160mph. Since the speedometers are about 5mph too fast as indicated this could be a european top speed limiter of 155mph (which is very common with MB and BMW cars) plus the error of 5mph could give a readout of 160mph or so.

It was reported by one of the big car magazines (Car and Driver?) that the 1995-1996 LS400 had no limiter and could hit about 155mph before fuel cut. I had a 1996 but never attempted this so I can't add facts to that report. I believe the 1997s cars did get the 149mp limit which continued until 2001 when it was dropped to 130mph on the LS430 which continues as the top limited speed for the LS460.

The fastest stock Lexus is the IS-F which is limited to 170mph