Rev Limit Raise

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Django91
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Rev Limit Raise

Post by Django91 »

Hello guys,

Would it be possible to raise the rev-limiter past 9500 rpm on the standard 231 RX-8 whilst run on the standard ECU?

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Re: Rev Limit Raise

Post by 13Black »

Possible, yes.

Benefits? Hardly.

Risks? Yus.
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Re: Rev Limit Raise

Post by MightyCondor »

Why would you want to? Power is already falling off a cliff at 9,500 rpm on a standard engine.

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Re: Rev Limit Raise

Post by Ollie »

Was going to say don't you only benefit from upped rev limits if your rotating assembly is balanced and lightened with porting done too?
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Re: Rev Limit Raise

Post by Django91 »

MightyCondor wrote:
Wed Jan 08, 2020 4:46 pm
Why would you want to? Power is already falling off a cliff at 9,500 rpm on a standard engine.

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Agreed, was just wondering of means to stay within power-band longer, without dropping below 7k revs on upshifts, but like you said, power falls off significantly past 8200 rpm. so not much point revving past 9500 rpm
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Re: Rev Limit Raise

Post by Vian »

That's the argument in favour, yes. If memory serves it only needs raising by about 300rpm to do that, and that's what's been done to mine with the RRP full remap.

Does it make much difference? Nah. Do I cane it up to 9,800rpm more as a result? Nah.
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Re: Rev Limit Raise

Post by Dr. FrankenRex »

As said, not worth it and comes with some serious risks on a standard engine
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Re: Rev Limit Raise

Post by warpc0il »

The only possible benefit I could consider would be on some tracks where you might currently be hitting the limited in a particular gear around a specific corner. Without having the option of changing the final drive gearing, you're left with either accepting the loss of drive, which can also upset the balance of the car, or taking a higher gear into the corner, which may compromise your drive out.

The latter is usually the best approach but having more headroom on the limiter does give you more options.
That said, this is a very niche example and the potential issues outway the benefits.
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Re: Rev Limit Raise

Post by 350matt »

If you were to shorten the inlet tract to tune the engine to a higher speed so peak power was 8800rpm for example then yes you'd want a higher rev limit but there's a bit to done mechanically to make it safe to 10,000rpm
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Re: Rev Limit Raise

Post by New Duke »

warpc0il wrote:
Wed Jan 08, 2020 5:03 pm
The only possible benefit I could consider would be on some tracks where you might currently be hitting the limited in a particular gear around a specific corner. Without having the option of changing the final drive gearing, you're left with either accepting the loss of drive, which can also upset the balance of the car, or taking a higher gear into the corner, which may compromise your drive out.

The latter is usually the best approach but having more headroom on the limiter does give you more options.
That said, this is a very niche example and the potential issues outway the benefits.
The wisdom of the Spin Doctor shines again! This. Totally this.

I had my rev limit raised specifically because there were some corners on some tracks that I wanted a bit more headroom without having to change gear for a second or two, or hold it at the limit and harm the lap time. The bonus is that you don't risk unbalancing the car with the gear change... especially if something unexpected happens in the braking zone (as is all too common at track events).

I only use it a few times a year mainly on track in specific places. But considering it was free as part of an engine tune, there was no reason not to.

Just don't do it all the time is the advice I was given by my expert.

Some people here are of the opinion that the engine is theoretically safe well above 10k.

*It's also handy to have in street races where the gear change would do more harm to your time than pushing higher in the revs in the same gear... but you didn't hear that from me 8-[
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Re: Rev Limit Raise

Post by Conan »

Hi Toby,
It’s very easy to lift the Rev limit 300 Revs on the standard ecu just by changing the values.
Listen to what 13 Black said though 😉
I had my rev limit increased after a rebuild because I wanted to try it and it gave me the option of holding a gear a touch longer if close to an approaching corner etc.
I have raced cars for a considerable number of years, won races, championships and lap records.
I use the option a few times per year on certain parts of some tracks.
Unless your racing or 2/000 sec really matter to you on a track day then it really won’t benefit you and could easily shorten your engine life.
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