G'day all
I'm a newby to the group
Has anyone got a fix for the speed limiter other than converting to mph? I come from the land of OZ so I need kph. Love the car sc400 but I can't get over 179 kph (110mph) on my favourite road.
Any clues?

 

Purchase an APEXi Rev/Speed Meter (RSM) and it will remove the speed limiter. Fairly simple to install. Comes with instructions. If you purchase the new version of the APEXi RSM then I would recommend the G-Sensor as well. So you can measure power output (in hp, I cant work out how to change it to kw yet!!!) and how many lateral G's you are pushing when you go through a corner. I recently inststalled one in a Toyota Camry (dont ask me why he wanted it... He's a rice boy at heart... he's only pushing 180hp.... ). You can get one for about AUS$440 retail or join a club like exclusive.i8.net (or .com cant remember, he's Melbourne Based) and get a club discount (about AUS$410?). Ask for David if you go to exclusive.i8.net Tell him Toan sent you and he will look after you. He's an Australian distributor for APEXi, so you get full australian warranty etc if anything goes wrong. and he can install it as well (not sure about installation price). It's a simple install if you are a DIY kind of person and dont mind slicing ECU wires. The ECU for the Soarer is located in the footwell on the passenger side. Right under the glove box.

The Mk 1 APEXi Rev/Speed meter will also work (about AUS$300), but it looks crap compared to the new model. I dont beleive the new model is released in the US yet, so no english manual You will recognize the new one by a electric blue dot screen showing graphs and logs or people driving. The old one is just 3 sets of numerical digits.

Hope that helps.

Toan

 

Thanks for being honest about your vehicle, and not feeling ashamed about yourself being unable to past 110mph..Guess what? The speed limiter is limited is up to 100mph from what I've heard.. Believe me, I've looked into this before. I've even tried it many times.. Let me guess.. The reason you were able to hit 110mph was because the road was a slight downslope. You were barely able to squeeze out the extra 10mph... My SC300 on a flat road can barely past 100MPH..All those other people talking about how they hit 140+ mph.. all bull..I'm here for honest questions and answers and not to impress.. Someone told me that you could possibly remove the trac fuse under the hood to disable speed limiter.., but i've tried.. no difference.. Good luck. Let me know if you find out the trick.. take care

j0hny

 

For what its worth, I was informed that the limiter was 152 or 156 MPH (at least on SC400's), and I have actually seen it printed somewhere; like Motor Trend or something. I have seen over 140 MPH myself, honestly, and she never missed a beat. Pulls strong to 130 w/ overdrive off. I was racing my buddy's 2000 C-5 auto. He spanked me below 100 (badly too) but from 100 up, I actually out accelerated him. He wimped out at 135, and I wimped out at 140. Car was like it was on silk at those speeds, and was still asking for more at 140, but I gave up.

Honestly, I think maybe California models have a lower limiter. Where do you live? On the interstates here, traffic runs about 90 mph w/ little traffic, and passing people gets you up to 110 and 120 on a regular basis.

Keith

P.S. That would suck having to pay $200-$300 to break 100 mph. Sorry to hear that.

 

Hmm, that's funny...

I've gone over 130 many times...

 

Same here, 152 and she fell on her face.

Shane

 

sc400 top out @ 120mph w/over drive off. 150 mph easy with da over drive on..our cars are slowbelow 80mph becuase of the smooth tranny. but 80mph and up the road is ours..

 

That's how you usually kill the transmission

Come to think of it, our cars have 160 MPH speedometer, is this just for the look?

 

hey this is a pretty obvious question I'm sure, but talking about the overdrive being off, is that with the button in or out? Also what are you supposed to drive around with, on or off? Like I said dumb question, just curious, people keep talking about it.

 

Why would you want to try to top out your car with overdrive off? Overdrive is just a tall 4th gear (5th in later SC400s)... and you NEED to use your highest gear if you want to go as fast as possible. BTW... I know for a fact that both the 300 and 400 will do at least 130 stock.

Ahh.. this question has been debated a number of times and Ive actually heard different things. The overdrive gear is relatively tall and as with any gear you dont want to let the rpms go too low or you will put a lot of strain on the engine. Its like starting in 3rd gear... it will put strain on the engine and probably cause it to stall. On the other hand you dont want to keep the rpms high for an extended period of time either. Bouncing off the rev limiter isnt good for your engine! When driving around town it is unlikely that you will need to shift into 4th anyway so whether or not you turn it off or on is really irrelevant. In other driving situations it really boils down to common sense. When you're cruising on the freeway at 65+ its probably a good idea to use the overdrive (duh!). Otherwise youll be at like 5000 rpms in third gear. In my experience the only time you ever really need to turn it off is if you are trying to engine brake in 3rd or you want quicker response (i.e. you are racing and want immediate power). I have never had the problem of rpms dipping to low in 4th because usually the ecu takes care of that but I suppose if the rpms dip below about 1200 while the car is in 4th you might want to turn it off as well. My guess is this would be around 40-50 mph although I could be wrong. Hope that clears things up a little.

 

oh! and I forgot to mention the most important thing. The purpose of overdrive is really to maximise fuel efficiency when you are cruising at highway speeds. Basically if you dont want to get like 5 mpg on the freeway turn it on.

 

To QUOTE LEXO400SC
"All those other people talking about how they hit 140+ mph.. all bull..I'm here for honest questions and answers and not to impress" END QUOTE

I think you have a sick car or someone has put a Lexus badge on your Honda Civic, or do I smell a Troll?

The J spec V8 in stock form can reach over 160mph on the clock (about 7% over-read due to various innacuracies), after removing the 180kph (112mph) limiter which is fitted to all J spec cars and/or subsequently converting the speedo from KPH to MPH, my 2.5Ltr has hit 150mph the only thing stopping it from topping 160mph was the wife's screaming "slow down for ***** sake your going to kill us".

The J spec Soarer has a max "180" speedometer readout Klms or Mls depending on the conversion.

It is entirely probable that the US spec has a limiter around 150mph, in Europe we have cars capable of 200mph but the manufacturers have agreed to limit most cars to 155mph, even the outrageous Aston Martin Vanquish with 600+bhp is limited to 155mph.

O/D is meant to be normally "ON" allowing access to the top or 4th gear (in a 4 speed of course), for various road conditions you can switch the O/D "OFF" to acheive lower gearing.

Petersh:

You should speak to Rob Hayden (Australian Lexus Soarer Club) about having yours delimited ALSC or go to the LSOC and ask in the Members Forum.

 

Maybe it's too late for me to throw in my 2 cents, but oh well

The US-Spec soarers are electronically governed at 156 mph. Lexus advertised this in brochures and what not. I believe that in stock form, the US-Spec SC4 is gear-limited to 162 mph. I don't know the gear ratios for the US-Spec SC300.

There was an old post on these forums (or the old ezboard forums) where an SC300 owner had trouble going past 100. I don't remember the outcome but if you're having trouble hitting over 100 mph then there are engine problems. I hit 108 mph in my stock 1991 Toyota Pickup (going on a slight decline), I did 115 mph (hit the governor) in my friends '95 Accord (intake, exhaust, plenty room left to go higher). A 225 hp 2JZ-GE should have no problem in hitting over 100 mph.

 

I have the gearing charts for All J spec Soarers. I'm not sure if these include the US spec versions (I dont see why they'd change rations fo US), but if you want them I can send them out. These cover the 3.0L , the 2.5 Twin Turbo, 4.0L GT and 4.0L LTD. Just give me a reminder Soarer_GT@hotmail.com

Toan.

 

I believe the older (92-?) SC400s had no speed limiter. Car magazines reported a 144-150mph ungoverned top speed. I believe the first speed limited Lexus was the 98 LS400. These were supposedly limited to 149mph.

I've seen early manual SC300s listed at 138mph in the magazines. These guys do fairly accurate top speed runs averaged two ways for wind/incline.

Mine (before turbo- stock) with 100k would run to 125mph fairly quickly (Didn't get any real open spaces). Based on my 1/4 mile times, my 100k engine was making as much or possibly a little more power than what the magazine testers were getting. It felt faster top end than my Integra GSR, which was supposed to do 135-140.

Our 92 V-6 Camry would do an honest 122-125mph, so if you can't get 110 out of your SC, something very major is wrong in the power department.