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 Post subject: 1.8T tuning
PostPosted: Sun Jan 15, 2017 8:49 am 
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Joined: Sun Jan 15, 2017 8:39 am
Posts: 3
ECU Model: S60 Pro
Hello to all, as a newbie here I have couple of questions regarding to tuning of a turbocharged engine. Experienced only with S60 tuning on N/A engines, this will be my first one. I was checking the turbo options on DTA and one of things I do not understand is a PWM operation with wastegate and a turbo pressure target. I thought that it works like this - I have to check the turbo pressure on the dyno and make a pwm map to have the pressure I want. But if this is correct, why then there is a turbo pressure target map? How does this work? Or there is a possibility, that I will use only a target map and the ecu then operates the pwm valve without pwm map, just to reach the boost target?
I don't know exactly, if I explained right, what I do not understand, but hopefully yes...
Thanks for your advices!!


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 Post subject: Re: 1.8T tuning
PostPosted: Sun Jan 15, 2017 2:28 pm 
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Joined: Mon Jan 16, 2012 1:39 pm
Posts: 79
ECU Model: S40 Pro
Firmware Version: 58
i think that pwm map is only to operate the wastegate valve not to control the boost...so when you operate the wastegate valve (n75 or boost solenoid is it the same operation for both ? ) then you use the turbo target map...

its like the vvt system i guess you control the vvt valve with pwm and then set the vvt degree from cam targer map

but Alex ofcourse knows better...i will wait for his answer too


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 Post subject: Re: 1.8T tuning
PostPosted: Sun Jan 15, 2017 3:53 pm 
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Joined: Fri Feb 28, 2014 1:03 pm
Posts: 1118
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79
There are two options - open loop boost, and closed loop boost control.

Open loop just uses the PWM map, and ignores the target values. These target values are greyed out if the "Use PID loop?" box isn't ticked.
This is the most common, and works exactly like L.H. says. Simply alter duty cycle on the dyno until target boost is achieved.
Obviously as the wastegate spring gets weaker, so the boost will drop over time.

Closed loop will use the PWM map as a base, and then alter the duty cycle to match the requested boost.


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 Post subject: Re: 1.8T tuning
PostPosted: Mon Jan 16, 2017 5:39 am 
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Joined: Sun Jan 15, 2017 8:39 am
Posts: 3
ECU Model: S60 Pro
Thanks for an answer, Alex. So if I understand it right, the best solution is to make a boost with PWM map - that's how I get a functionable base and then fill the boost target map and use the closed loop for the road use. If I do this, the system will hold the demanded boost even if the wastegate spring gets weaker. Right?
As for the fuel mapping - I had an idea to map the engine with opened wastegate as a N/A engine or with a really low boost, then add the boost and for having a right AFR use and adjust manifold pressure corrections. Am I right with this procedure or this is not an usual sequence of tuning?
Thanks, Ladislav


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 Post subject: Re: 1.8T tuning
PostPosted: Mon Jan 16, 2017 11:01 am 
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Joined: Fri Feb 28, 2014 1:03 pm
Posts: 1118
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79
L.H. wrote:
Thanks for an answer, Alex. So if I understand it right, the best solution is to make a boost with PWM map - that's how I get a functionable base and then fill the boost target map and use the closed loop for the road use. If I do this, the system will hold the demanded boost even if the wastegate spring gets weaker. Right?

You don't have to use closed loop, just be aware the boost will drop a bit as the wastegate spring goes soft.

L.H. wrote:
As for the fuel mapping - I had an idea to map the engine with opened wastegate as a N/A engine or with a really low boost, then add the boost and for having a right AFR use and adjust manifold pressure corrections. Am I right with this procedure or this is not an usual sequence of tuning?
Thanks, Ladislav

Don't leave the waste gate open. It uses the case of the turbo to cool down, and you can damage it if it's permanently open.
Map at whatever boost you want to. The ECU will compensate for boost all the time, and only enter the base injector opening time in the main fuel table.


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 Post subject: Re: 1.8T tuning
PostPosted: Mon Jan 16, 2017 4:46 pm 
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Joined: Sun Jan 27, 2013 6:08 pm
Posts: 262
ECU Model: S60 Pro
Firmware Version: 29
We mapped my turbo bike as L.H. proposes and it worked out ok. We disconnected the intake boost pipe so although the turbo was still in line and compressing air this was vented immediately with the engine breathing NA. Once we had a good NA fuel and ign. map the pipe was re-connected and boost compensation tables were fleshed out. Whilst most blown installs load sense rpm against MAP only, with a bike this isn't particularly nice to ride as when NA / off boost, bikes don't have much vacuum signal so I preferred to use rpm v's TPS as primary load and use MAP as secondary. May not be the'usual way' but sometimes the 'unusual' works.


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 Post subject: Re: 1.8T tuning
PostPosted: Tue Jan 17, 2017 5:06 am 
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Joined: Mon Jan 16, 2012 1:39 pm
Posts: 79
ECU Model: S40 Pro
Firmware Version: 58
has anyone had try to map via map sensor a boosted angine but just using the main fuel map not using map sensor compensations at all ??


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 Post subject: Re: 1.8T tuning
PostPosted: Tue Jan 17, 2017 5:30 am 
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Joined: Fri Feb 28, 2014 1:03 pm
Posts: 1118
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79
katana wrote:
We mapped my turbo bike as L.H. proposes and it worked out ok. We disconnected the intake boost pipe so although the turbo was still in line and compressing air this was vented immediately with the engine breathing NA. Once we had a good NA fuel and ign. map the pipe was re-connected and boost compensation tables were fleshed out.V
That's fine. It's wedging open the waste gate that causes issues.

katana wrote:
Whilst most blown installs load sense rpm against MAP only, with a bike this isn't particularly nice to ride as when NA / off boost, bikes don't have much vacuum signal so I preferred to use rpm v's TPS as primary load and use MAP as secondary. May not be the'usual way' but sometimes the 'unusual' works.

I'm more than happy with TPS vs RPM and MAP compensations, but both have their advantages and disadvantages.


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 Post subject: Re: 1.8T tuning
PostPosted: Tue Jan 17, 2017 5:32 am 
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Joined: Fri Feb 28, 2014 1:03 pm
Posts: 1118
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79
iceman_n wrote:
has anyone had try to map via map sensor a boosted angine but just using the main fuel map not using map sensor compensations at all ??


Lots of people map this way. Some prefer this (speed density), others prefer TPS vs RPM (Alpha-N) with MAP compensations.

Just remember to zero out the MAP compensations if using MAP as load. I had to explain over email once why this didn't work....


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 Post subject: Re: 1.8T tuning
PostPosted: Tue Jan 17, 2017 1:59 pm 
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Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2901
Location: Norn Iron
ECU Model: No ECU
iceman_n wrote:
has anyone had try to map via map sensor a boosted angine but just using the main fuel map not using map sensor compensations at all ??


That is the normal and most common way of tuning a boosted engine.


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