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Removing the speed restrictor from the Roadster - Engine & Ancillaries/Gearbox - The Lotus Forums Jump to content
Neal H

Removing the speed restrictor from the Roadster

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Is it possible to have the 145mph speed restrictor removed from the Roadster? I have a hard top with mine and if I have the soft top on I'd remember to stay below 145 (promise!)

 

I know it's irrelevant 99% of the time, but it would be nice for the occasional autobahn run or track day at the Nordschliefe.

 

Neal.

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The best one to ask would be Komotec

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But how stable would the car be without the front and rear spoiler a la the coupe?

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A good question. Like how stable is my Exige S coupe with soft top installed and how fast can I drive ? 145 mph like the roadster, less or more because of the spoilers ? Or is the soft top flying away then ? Seems no one really knows that until someone tries it

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The soft top will be suck off the roof and I'd not want it landing on my head at 150mph plus! I'd imagine if it did cause an accident and you'd modified the car you'd be getting used to porridge before long...

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Despite the various questions about spoilers and roofs, I'd still like to know whether the speed restrictor can be removed :)

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It can be on many German cars, so I don't see why not...

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speed restrictions are (only) coded at the ECU. You need someone with Lotus ECU experiences like KomoTec. They probably can recode the ECU and remove it.

Spoilers should interest you: The roadster isn't build for higher speeds, even with a hard top. Because of the missing from and rear spoilers you won't have enough down force at higher speeds. The car gets "too light" and can loose grip. Dangerous.

Edited by Blue1000

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The Roadster still produces downforce, just not as much as the coupe...

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Sure, it has downforce, but simply not enough for such a speed. The faster you are the more downforce a car needs. There is a good technical reason why Lotus ( and all others) add both front splitter and spoiler. Your decision...

Edited by Blue1000

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The faster you go the more downforce you produce...

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So splitter and spoiler are there just for fun and not needed ?

I was driving the Exige 174 mph four weeks ago (with hardtop). I wish you good luck trying it without a perfect aerodynamic and without enough downforce

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Not sure if any one using the soft top feels that the front of the soft top catches the air on freeway 100+ abit annoying/concerning at higher speed.

My cables have been tighten but there is still wind catching in the mid section

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So splitter and spoiler are there just for fun and not needed ?

:huh:

Please don't put words into my mouth, it's very rude mate. Of course they are effective and produce MORE downforce but my point is, even without you are still being pushed down into the road by the aerodynamics of the car. It certainly produces enough downforce as we don't see cars without aerodynamic aids taking off at high speed every day do we...

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Don't think I'd want to exceed 100, let alone 145 with the soft top in place!

The fastest I've ever been is 141 (satnav speed, Evora, Germany) so it's not a big issue, but when asked "how fast does it go mate" I'd like to say 174 without having to explain about the restrictor

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Just say fast.......

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On 29 May 2015 at 18:32, Bibs said:

:huh:

 

Please don't put words into my mouth, it's very rude mate. Of course they are effective and produce MORE downforce but my point is, even without you are still being pushed down into the road by the aerodynamics of the car. It certainly produces enough downforce as we don't see cars without aerodynamic aids taking off at high speed every day do we...

Ahem, remember the original Audi TT? Maybe not as well known in UK, but there were sufficient incidents in Germany to warrant a major recall and that ugly rear spoiler. I had a few of those as rentals and they really were adventurous above 200 Kph. 

 

I can imagine similar issues with the Exige roadster at speed. 

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It produces downforce. And the faster you go the more it produces.

 

Honestly.

 

There are no two ways about it...

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Are we not discussing the Roadster, which isn't fitted with the splitter and wing for exactly this reason since it's been designed to be driven with no roof, unlike the coupe? Take the roof of the coupe and the rear wing is no longer effective due to the turbulence and the splitter then unbalances the car.

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Most supercars have some spoilers and splitters, partly retractable. If not then they are designed for high speed from the beginning. Not the Elise based Exige. Each car has it own limit. The Exige needs Spoiler, Splitter and hardtop for a secure top speed. Fitting a hard top to the roadster isn't enough. You're right, it's a similar problem if you remove the hardtop from the Coupe. That's why I drive a max of 230 kph with the soft top and 180 kph without roof. 

 

Anyway, back to your question: the speed limiter is ("only") some code at the ECU, don't know if it's possible to recode, but you need a ECU specialist to unlock the full speed. Ask the KomTec guys. You will loose your warranty then.

 

By the way, you can also unlock the Race Mode for all Exige at the ECU (without having the 2.700,- € Race Pack ordered), it's build in with the BOSCH system   ;)

 

4o4gntcv.png

Edited by Blue1000
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That certainly clears up the question of how the limiter works and whether it can be removed. It would seem to need an ECU replacement, or a reflash with 'Coupe' settings, and getting either out of Lotus would probably be impossible!

Whether it would safe to run a Roadster at 150+ is a separate question. I suspect it would be okay, as certainly big power Elise's (Honda/Audi conversions) have been known to run at those speeds without major issues.

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The soft top will be suck off the roof and I'd not want it landing on my head at 150mph plus! I'd imagine if it did cause an accident and you'd modified the car you'd be getting used to porridge before long...

When you remove the roof, there is a bright yellow and black sticker on the windscreen surround warning that there is danger of death if you remove the roof. I removed mine and I didn't die, but there again I didn't take mine over 145mph. I wouldn't risk taking it on the Autobahn with the soft top on, I would leave the roof on and the soft top in the boot. I also think that you should tell your insurance company that you have modified your car.

Oops sorry we are talking Roadster here, mine was a Coupe.

My Elise SC was stable with roof off at 146mph ( GPS speedo) and my Evora 164mph (sat Nav indicated). On both occasions there was however a very noisy chirping coming from the passenger seat :)

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bit of a zombie thread but thought I'd comment.

with aero its all balance. 

the Audi TT had issues as it produced (like most cars) lift at the back (afterall cars in profile are essentially aeroplace wing shaped). However this wasnt balanced with the front so at high speed the loading of the tyres moves forwards as the rear lightens so provoking an oversteer situation. As the Exige in both forms produces front and rear downforce its not omparable.

lots of aero downforce isnt always good. take the S1 elise - it had nearly 10 times the front and rear downforce of the S2 yet the S2 had much better high speed stability. The reason was the high downforce made the S1 very sensitive to wind changes during high speed corning.

Now the Exige Coupe is designed with a front splitter and wing. for the wing to work it needs damn good airflow to it and the roof provides this. as such the aero is in balance and everything is happy. However, take the roof off and the turbulence dramatically reduces the quality of the air on the rear wing and as such its not as effective. This obviously doesnt affect the rear wing so as with the TT, the rear will get lighter relative to the front making a tendancy to oversteer.

with the roadster, it doesnt have a rear spoiler to provide the majority of the downforce. similiary, it doesnt have the front splitter. the aero isnt anywhere near as vulnerable or dependant on airover the car. Its also softer sprung so able to absorb  road irregularities and less likely to have a bump destabilise the car.

As above - plenty of s1 and s2 elises have been pushed above thr exige power levels without additional aero. plenty of normal cars fitted with silly power without any downforce to speak of. As long as the front a d rear remain balanced snd you are not looking to set lap records on bendy tracks then ive not encountered issues. Motorbikes seem to do pretty well hitting 200 without wings and things ;) 

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We are not only talking about downforce, we are talking about downforce at any time.

I don't know, if you know this video where a visitor died. The Nissan has a lot of downforce, but not after this jump area.

Backflip accident

If this video is against any rule of TLF, please erase the link.

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