so... what does "duty cycle" actually mean?!
Turbo Mini Forums

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!

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

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

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

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

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.

What controller is it you are looking at?

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

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.

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!

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

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

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.

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

In the 13's at last!.. Just

Edited by Brett on 18th Feb, 2016.

Yes i moved to the darkside

Instagram @jdm_brett

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

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.

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!

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?

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.

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.

I have a 'nic' mind and can only focus on the ANALyzer

Edited by D4VE on 19th Feb, 2016.

Edited by stevieturbo on 19th Feb, 2016.

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

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

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).

Edited by PhilR on 20th Feb, 2016.

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