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Home > Beginners Tech > so... what does "duty cycle" actually mean?!

Turbonator

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AKA: Smegmium

Derby, ish

I'm just about to buy an electric boost controller, and it refers to "Duty cycle" in % , I have seen this before but can someone explain what is actually means relating to boost control?!

I just want to control max boost by PSI!


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John

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Mongo

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If something is worth doing, it's worth doing half of.


Turbonator

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AKA: Smegmium

Derby, ish

Thanks John, so how does that relate to the control of boost? is the pulsing of the solenoid in effect bleeding off so its not a sudden opening of the wastegate? or a partial opening?

"If its not broke, whack a turbo on it"

https://www.youtube.com/c/turbominitv


Carlzilla

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Not sure which way in the scale boost controllers work but at either 0% or 100% duty cycle (the boost controller valve showing actual boost pressure to the wastegate, as if it wasn't fitted) you would have boost pressure governed by the wastegate. Anything off the end scale the pwm will open and close the needle valve very fast allowing a small air leak, allowing boost pressure to rise, either way base boost pressure is still governed by the wastegate I presume.

On 26th Jan, 2012 Tom Fenton said:
ring problems are down to wear or abuse but although annoying it isn't a show stopper

On 5th Aug, 2014 madmk1 said:
Shit the bed! I had snapped the end of my shaft off!!

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Tom Fenton
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What controller is it you are looking at?


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


Turbonator

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AKA: Smegmium

Derby, ish

Not 100% sure yet (advice welcome) I also believe the Microsquirt can be configured to deal with boost control....

"If its not broke, whack a turbo on it"

https://www.youtube.com/c/turbominitv


evolotion

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more duty, more air bled off, higher boost.

0% duty is wastegate pressure.

cheaper boost controllers will work on duty, so you want 10psi , and your gate opens at 6, you try 20% duty, say that gives you 12psi, so you try 17% duty and hit 10. Id be supprised if any boost controllers still work like this tho these days, its pretty early 90's tech.

better boost controllers will allow you to specify a target boost, say 10psi, and a start duty, the idea is the start duty gets the boost to within a few psi of the target and allows the controller to take over closed loop controll of the boost, if you google PID controll systems you will see why this simplifies things.
A side benefit of this, is you can intentionally specify a duty that is too low so you get a soft hit of boost to keep traction, or a duty thats too high so you get a nice fast surge of boost (with a little overshoot) if you like that sorta thing.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.


Tom Fenton
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I'd have thought the same Denis until a customer bought an AEM TruBoost for me to fit. Fecking thing is only open loop e.g. set a duty and get what boost you get! I was also amazed that a product these days with its own MAP sensor onboard couldn't do closed loop!


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


D4VE

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lowestoft suffolk

Would also be interested in peoples suggestions of controllers available now days

On 24th Oct, 2015 jonny f said:
Nothing gets past Dave lol

NOTHING GETS PAST ME!! *tongue*

1/4 mile 14.7 @ 96mph 12psi boost
Showdown class A 2nd place 18.6 @ 69mph


Turbonator

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AKA: Smegmium

Derby, ish

Good answer Denis, thank you!

I was looking at something like this:
http://www.ebay.co.uk/itm/322007561142?_tr...K%3AMEBIDX%3AIT

However that one only appears to display BAR.

"If its not broke, whack a turbo on it"

https://www.youtube.com/c/turbominitv


evolotion

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Im a big fan of the (now rather old) apexi AVC-R. 2 boost modes, self learning, can adjust boost curves manually, boost by gear, and a simple clear easy to read at a glance screen That ebay one looks interesting, and if it operates as claimed its better than some brand name controllers.

There are a lot of boost controllers out there i have found down right painfull to use, yet others swear by them so take what you read with a pinch of salt :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.


theoneeyedlizard

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That does look interesting. Very interesting price.

I was really considering the AEM Tru boost , but didn't realise it wasn't closed loop.

Now if I can just get over the fact that it won't fit into the hole where my current boost gauge lives*oh well*

In the 13's at last!.. Just


Brett

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On 18th Feb, 2016 Tom Fenton said:
I'd have thought the same Denis until a customer bought an AEM TruBoost for me to fit. Fecking thing is only open loop e.g. set a duty and get what boost you get! I was also amazed that a product these days with its own MAP sensor onboard couldn't do closed loop!


yeah it really is scary just how dumb some of these 'high tech' controllers are

apexi all the way for me, my ecu has basicaly the avc-r inside it (apexi ) but is capable of controlling my boost at 4 select able targets but atm im also using a separate apexi profec b ( dumb open loop ) because its 1000x easier to tweek the boost while driving/ tuning lol

imo the apexi avc-r is the one to go for, its pricey but best one hands down. i believe it can do boost by gear and mapable boost

imo the AVCR is actually better than fitting a stronger wastegate spring, all wastegates creep around target boost pressure loosing response the AVCR can remove all wastegate creep and also keep boost spikes to a minimum, this absolutely critical when pushing the limits

Edited by Brett on 18th Feb, 2016.

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theoneeyedlizard

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The Boom Boom speaker Police!

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But where do you hide such a hideous looking thing?

It's like a 90's JVC radio

In the 13's at last!.. Just


Tom Fenton
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On 18th Feb, 2016 theoneeyedlizard said:
But where do you hide such a hideous looking thing?

It's like a 90's JVC radio


Baae haae haae

But so very true

I was mega disappointed with the AEM. If if could do closed loop it would be a ace little gadget that would fit nicely into a dash.


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


burcy35

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Hornsea

I run a tru boost and like you say it's a great looking little gadget. But it does has lots of setting which I suppose helps to compensate for not being closed loop. I had a bit of bother setting spring rate and crack pressure but now it's set up really well.


Tom Fenton
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Fearless Tom Fenton, Avon Park 2007 & 2008 class D winner

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Sorry but all the settings just set it up, it isn't closed loop and never will be, which to be honest is really fucking lazy of AEM!


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


burcy35

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Hornsea

OK. I am picking up on a slight vibe that your not the biggest fan of the aim unit tom. So which electronic controller would you recommend?


Tom Fenton
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Fearless Tom Fenton, Avon Park 2007 & 2008 class D winner

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I wanted to like the AEM I really did, I do like the rest of the AEM kit I have used, the wideband lambda is great I must have fitted half a dozen of them now, but having fitted the truboost to a customers car I was really disappointed with it, it SHOULD for the price do closed loop in my eyes.


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


PhilR

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That is pretty lazy of AEM - All the hardware to do closed loop is there, but clearly, not the code. They even implemented over-boost protection which is part of the way towards fully closed loop.

The AEM will essentially function like an basic bleed valve. IMO even a cheep spring and ball type bleed valve would be a better choice. It does have a pretty LED gauge though and you can wire in a TURBO button lol.



Seriously though, for that money I'd rather make my own.

Edited by PhilR on 19th Feb, 2016.


D4VE

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Edited by D4VE on 19th Feb, 2016.

On 24th Oct, 2015 jonny f said:
Nothing gets past Dave lol

NOTHING GETS PAST ME!! *tongue*

1/4 mile 14.7 @ 96mph 12psi boost
Showdown class A 2nd place 18.6 @ 69mph


stevieturbo

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Northern Ireland



On 19th Feb, 2016 Tom Fenton said:
Sorry but all the settings just set it up, it isn't closed loop and never will be, which to be honest is really fucking lazy of AEM!


I've never used one, but are you 100% sure on that ?

Have you asked AEM ?

Many other controllers operate closed loop, but have no actual settings that would alert the user that it is closed loop, because all those aspects are kept away from the user as no doubt they'd screw them up lol

So whilst they are closed loop, they dont have a huge range of control and with them all you still need to set base duties, and the usual gain etc functions which while they dont always say it are to a degree fine tuning the closed loop abilities.

I recall a guy on a US forum who tried to argue with me that his EBoost2 was not closed loop, and he was furious blah blah blah.
Despite explaining it to him numerous times, I couldnt get it through to him.

Mind you, he did eventually apologise after he contacted Turbosmart and they told him exactly what I had told him.
But I did find it odd there was no real mention of the fact in any of their instructions for the unit. I just know from using them it absolutely operates in closed loop, because once setup they are bloody superb.

Edited by stevieturbo on 19th Feb, 2016.

9.85 @ 145mph
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speed didn't kill me, but taxation probably will


stevieturbo

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Just had a look through the instructions, and coincidentally seen another post a few mins ago on one of the V8 forums...

Truboost sounds crap ! No element of closed loop control at all. That's crazy in this day and age especially given the price.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


PhilR

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For the same price as the AEM, you can buy a Microsquirt with closed loop and mappable boost control (not to mention everything else it does).

On 18th Feb, 2016 Smegmium said:
Good answer Denis, thank you!

I was looking at something like this:
http://www.ebay.co.uk/itm/322007561142?_tr...K%3AMEBIDX%3AIT

However that one only appears to display BAR.


Just had a good read - it looks very interesting, does closed loop and open loop (with full control over the closed loop PID settings if you really want). It looks quite 'home brew' on the face of it, but that's no reason to doubt it does what it should.

...Interestingly, he also does a wideband controller too.

Edited by PhilR on 20th Feb, 2016.


Turbo This..

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Previously josh4444

Australia, brisbane

i thought they worked similar to idle air control valves? mega squirt has some boost control stuff that i bleive a soliniod get connected to than to the waste gate

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