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Cut spark instead of fuel at rev limiter?

_R_J_K_

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When a VP 5 litre hits the rev limiter, is it possible to tune it in such a way as to have the ECU cut the spark as opposed to cut the fuel supply? Or is this not possible because of the dizzy setup?
 

greenfoam

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You can do it if you go aftermarket ignition
 

Cursed CX8

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out of interest? why would you want this to happen?
I honestly dont know, im not asking a smart arse quesetion
 

Immortality

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as foam mentioned after market ignition systems like MSD/Crane do this. it's known as a soft rev limiter. basically it allows you rev the engine right up to the limiter without it "bouncing" like it does with the factory rev limiter. with the factory limiter if you free revved the engine in neutral the engine would rev past the limiter before it could catch it. with a ignition based limiter this won't happen.
 

Matt_vp

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out of interest? why would you want this to happen?
I honestly dont know, im not asking a smart arse quesetion

Would rather have the cyclinders not fire over going lean, when it fires and the isnt enough fuel in the chamber. Probly not worth it with a standard motor and setup.
I dont like hitting the limiter for this reason. I might just be pananiod because ive been through a few engines.
Matt
 

_R_J_K_

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out of interest? why would you want this to happen?
I honestly dont know, im not asking a smart arse quesetion

Some of my mates are into Japanese cars, and were talking about the "Bee*R" rev limiter system (I have no idea what it's all about) that are typically used on Japanese cars sometimes, some after market ECUs also support their own version of this system. If you go and watch some of the videos around the net of these cars doing burnouts, they typically shoot flames out the back because of the unburnt fuel and make tons of noise,

So... My mate with the 5 litre hooked on to this idea (because he wants his burnouts to be spectacular, typical wank factor thing), and wondered if it could be implemented with a memcal retune.

There are good reasons for this as mentioned by immortality and Matt_VP, there are also a few downsides to it too. Me personally, I'd just rather keep away from the rev limiter to be honest.
 

Matt_vp

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Some of my mates are into Japanese cars, and were talking about the "Bee*R" rev limiter system (I have no idea what it's all about) that are typically used on Japanese cars sometimes, some after market ECUs also support their own version of this system. If you go and watch some of the videos around the net of these cars doing burnouts, they typically shoot flames out the back because of the unburnt fuel and make tons of noise,

So... My mate with the 5 litre hooked on to this idea (because he wants his burnouts to be spectacular, typical wank factor thing), and wondered if it could be implemented with a memcal retune.

There are good reasons for this as mentioned by immortality and Matt_VP, there are also a few downsides to it too. Me personally, I'd just rather keep away from the rev limiter to be honest.


Does your mate have a turbo on his v8?
Bee r is mainy used to build boost for a launch and also good for burnouts. Something to do with the extra fuel making the zorst hotter and making the engine make boost with no load, aswell
as beeing a good quality rev limiter.

Taken from: http://www.neweraparts.com/Default.aspx?tabid=54&List=0&ProductID=17

This is Bee*R’s popular two-stage ignition cutting rev-limiter. It is used to prevent damage arising from over-revving your engine. Part of the reason for its popularity is the large flames and loud bangs it produces from the exhaust when active!

The way in which it works differs from the factory rev limiter in that it is an ignition cut, as opposed to a fuel cut. The reason for this is because if an engine (particularly turbocharged) regularly hits a fuel-cut rev limit (such as in high performance driving, or particularly drifting) engine damage can arise due to the lean condition produced when the original ECU shuts off the fuel pump. The BEE*R rev-limiter allows fuel to pass into the engine still, limiting engine speed by disabling the ignition signal. The Bee*R rev limiter is fully adjustable in 500rpm increments, for safety reasons allowing only a lower rev-limit to be configured than standard. If you have spent a lot of money tuning your engine, or are running at high RPM’s for extended periods of time, it could be recommended to run a lower rev-limit to prolong engine life. Both Formula 1 and JGTC cars use ignition cutting rev limiters, so it is a fully race proven concept.

The Bee*R can also be used as a “two stage rev limiter”, as an aid for launching your car. The Bee*R is configurable for two different rev-limits. A lower rev limit can be activated by a switch, the handbrake switch often being used. This configurable lower limit, can be set to the optimum RPM to launch your particular car from in 500rpm increments. When the handbrake is released, the usual rev limit comes into action, allowing quick launches, and full performance down the strip.

The Bee*R rev-limiter has another final neat feature. The gain control knob allows you to adjust the frequency of the ignition cut. This in turn changes the frequency and sound of the flames and bangs from your exhaust!

Available for use with all rotary, 4 and 6 cylinder engines. (No V8 application)

Matt
 
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greenfoam

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Mostly people in burnout comps like to hold the cars on the limiter once and a while during the burnout since it adds to the spectical. The ignition cut limiters soft different/better most different so and different is cool. This is why people like to run them. I'd also be dodgy on fuel cut limiters on a turbo car that was tuned on the limit
 

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In keeping with the theme, can i ask a question. I just got a 2010 SSV Sporty with 6.0ltr L76 with AFM and 6sp auto with active select. Just took it for a spin out to the 130km/h zone and checked out the manual shift mode and sport mode and to see how she goes now that i have run it in a bit (750km total) What i found sounds similar but not sure which one. In 1st just before redline, which looks like 6000rpm by the dial, but at about 5800 the engine dies. I think it then tried and died as i went for 1st again not second (haven't quite got used to which way yet) Tried again and seemed to time 1st to 2nd just as it cut out and got a small cough as i hit second. 2nd to third was good timed it just before. Does anyone know what they have doing this or should i post elsewhere? Also in Park it wont let you rev it past about 4000rpm, won't even pop up past it for a bit?
 

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In keeping with the theme, can i ask a question. I just got a 2010 SSV Sporty with 6.0ltr L76 with AFM and 6sp auto with active select. Just took it for a spin out to the 130km/h zone and checked out the manual shift mode and sport mode and to see how she goes now that i have run it in a bit (750km total) What i found sounds similar but not sure which one. In 1st just before redline, which looks like 6000rpm by the dial, but at about 5800 the engine dies. I think it then tried and died as i went for 1st again not second (haven't quite got used to which way yet) Tried again and seemed to time 1st to 2nd just as it cut out and got a small cough as i hit second. 2nd to third was good timed it just before. Does anyone know what they have doing this or should i post elsewhere? Also in Park it wont let you rev it past about 4000rpm, won't even pop up past it for a bit?

For starters why rev it so high in netural? You are probly hitting the limiter which i wouldn't be doing on a motor with 750kms on it.
Matt
 
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