Aurion Speed Limiter

[PsychoRez]

Hello!.

I wonder if anyone of you tried taking out the limiter on the Aurion?. I might be willing to do it but first i have some questions!.

1- HOW?.

2- Will Toyota know i took it out when i take the car in for service?.

3- Will it HARM the engine in any way?.

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And that's all i can think of for now.

But what i really want to know is if it will wear the engine down, Reduce its life?. I mean i know i wouldn't thrash it up to 260Kmph everyday, But i'd just like to know. I'm the kind of person that gets pretty obsessed about these sort of things. Basically would like to know the negatives when it comes to doing this, An experienced opinion would be highly appreciated.

Thanks!.

[DJKOR]

It's not that simple to do so yet:

1) It is programmed into the ECU. The only way you are going to override it is to have someone reflash your ECU. I don't think anyone out there is capable of that yet for this car. I would be more than certain that Toyota's Intelligent Tester has some feature to do that, but unless you can find someone with this, I doubt Toyota will do it for you easily.

2) I would lean towards the NO side. This is providing you find someone capable of hacking the ECU. However, I'm not exactly sure on what Toyota do when they plug their system into the ECU during the service. If the system is meant to pick up on any abnormalities, then it could pick it up. It's hard to get a definite answer on that one.

3) So long as you leave the rev limiter intact and/or don't go above redline, the engine should take the extra speed no worries.

Engines are most efficient when they are running at their maximum designed speed. Apart from that, they are also built to run within its entire rev range. It's not your speed that will contribute to engine wear, but more the RPM and the variations of it. Going fast isn't going to put much more stress on it than pushing it hard under moderate speed.

[pegaxs]

Are we talking about speed limiting, like on the imported Skylines (capped at 140km/h) ? or rev limiting ??

1: To remove rev/speed limiter would require some form or firmware hack for the ECU or a modification to interrupt the signal to or from the ECU and fool it into thinking it was doing something it wasnt. much like the Suzuki Hayabusa speed hack that involved the ECU thinking the bike was only doing 299km/h but was clearly doing more. (clearly... i dont know, 299km/h V's 325km/h, you would notice yeah ??)

2: depends on how the hack was applied. I doubt they could tell, unless it was something really overt. say, a big black box hanging off the side of the engine that isnt normally there, or the ECU no longer works with the tester because is an aftermarket ECU

3: Rev Limiter: simple form, yes. an engine is only designed to run at a set maximum speed. If you are talking about removing the rev limiter, i dont even know why you would bother for every day driving. these engines for the size of them produce a lot of power and rev fairly smartly. why you would want to get more out of it is intriguing to say the least. If you over rev the engine, you leave yourself over to spinning bearings and cramming pistons into valves. never pretty and fairly conclusive when you take it back in for warranty... why are the valve heads hanging out of the piston crowns ?

once you get above certain rev ranges, it starts to affect other things, such as crank shaft balance, torque converter balance, gearbox input speeds, fuel injection keeping up, oil cooling/pressures. The Aurion engine is designed with an ECU that knows these limits. a short burst above the redline wont hurt it in the short time, but repeated trips into red and beyond at standard engine config will only result in tears after long term exposure.

3: Speed Limiter: Harm the engine ? Not really. a car has an actual top speed, and a theoretical top speed. one involved wind resistance and rolling resistance, one is Max RPM inserted into an equation that works out gear ratios and wheel diameter to give you that number. Dont worry, your car will never get to that speed unless its on an unladen dyno... and even still then... it will stop short. On the open road, you would need a huge run up to get anywhere near the top speed. are you planning on racing this car ? because you have other issues to worry about if its top speed you are looking at doing, such as wind drag and handling, transmission cooling, drive line cooling, brakes for stopping, tyres that can go that fast. Just because a car can do 300km/h or has 300km/h on the speedo, does not mean it is capable of being there.

As for experienced opinion, i was an automotive mechanic for 15 years. i have raced anything that had wheels and an engine. My brother graduated as the top engine reconditioner the year he finished his trade and now spends his time building race engines. I have rebuilt engines with him from as small as model aeroplanes to 16V 149 Detroit earthmoving engines. 2 strokes and 4 strokes. from lawnmowers to speedway sprint car engines. Together with my family who own an engineering company, we have built race cars from as small as formula 500 (TQ midgets) to V8 open class track cars.

Hope that helps :)

Just on a side note because i was bored, i went searching, and it seems the Aurion has a 228km/h speed limiter ? dont know... can a Toyota tech confirm or deny this ?

i have made up a excel template to show what your car is capable of in theory.. lets say at max rpm where horse power is calculated, 200kw @ 6200 rpm, in 6th gear the wheels would be doing 347km/h providing you have the standard wheels on it :)

Edited January 10, 2009 by pegaxs

[PsychoRez]

Thank for the response DJKOR!.

And WOW pegaxs, Highly appreciate the detailed response!.

Yeah, I'm talking about the actual speed limiter!, Yes it limits the car to 220Kmph or so, 6th gear is basically useless when you're going that fast in the Aurion because you don't even use it!.

And yeah, The only thing i fear after doing this is wind and handling issues!, At those sorts of speeds things like strong wind can become serious issues, correct?. I don't really think going 250-260Km/h will make my transmission overheat..Will it?. I just want to have the option to go faster when needed "When testosterone kicks in", If you know what i mean.

But i still don't know how to do it. I guess i should wait until somebody around here learns how to do it.

[Soloman]

Really there is no need to go that fast.. this is not legal either anywhere in Aus..(used to be in NT..F**k the NT labour gov)

Anyways once the car is over 200kms it becomes very unstable. i dont think anyone will release something to take the speed limiter off. toyota def will not do it.. i dont think the stock tyres are rated to go that fast..

Have you gone above 200kms.. just go above it in a aurion.. see how it feels.. then get a mate with a rice burner (Wrx STI or GTR) and get them to do it..

u can tell the difference.. one car is ment to go above 200kms.. one car isent..

[PsychoRez]

I have done 220Kmph a few times. I don't think it was unstable or anything, Think the condition of the road has more to do with that. I don't know i my tires are built for those types of speeds, I do know the tires we get with the Aurion here are different than the ones you guys get in Aus, Dunlop, right?. We get Yokohoma here, Don't really know much about tires so i don't know if thats any better, Definitely need to check up on it.

And of course I'm not expecting some super performance out of the car, I know my car's limits!. It's just nice to have the option to go that fast when needed.

[DJKOR]

To remain within specifications, replacement tires for the Aurion must have a speed rating of no less than category 'V'. Under the standard, category 'V' speed rated tires can handle a speed of 240km/h for a duration of 10 minutes without danger to the tire itself.

Our Aurion's here come with Dunlop or Michelin tires. I'm not sure about the Dunlops, but the Michelins are category 'V' speed rated. If you have Yokohama's from factory with your Aurion, they are most likely the C. Drive. Those would be speed rated category 'W', which means the same as above, just up to 270km/h.

The Aurion is in fact quite stable at 220km/h and it does come down to the road you are on. If you really want to remove your speed limiter, then that's your choice. It's just a matter of whether you can find out how. For me, I think that it is quite pointless to go to the effort for it since there isn't a real need to.