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Old 10-23-2008, 12:14 AM   #1
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Default question about linear tps and boost duty table

What are you guys setting your duty targets to below full throttle? What are the benefits to running more or less duty at lower throttle positions. For instance, would running 100% duty cycle up to 4000 rpm and below 30 percent thottle help spool the turbo quicker at that rpm range or are you moving enough air then anyway that it's unnecessary? Or do you run less duty cycle at lower tps positions and why?
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Old 10-23-2008, 12:30 AM   #2
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100% DC at low TPS kinda defeats the purpose of have the VTPS Boost control. I like to modulate boost with throttle position. Isn't this the reason the 1.6 guys go to the automatic TPS? For low traction conditions like rain/snow it really helps to be able to keep the boost from coming on to quick and you are light on the throttle.

If i set mine to 100% at 30% throttle my car would be so jerky and break loose too easily.

I like to figure out my top row to give me the boost level i want.
2nd row down is 60% TPS and is identical to above row. So from 60% throttle up I have the same boost duty cycle.

3rd row down is 50% TPS. I do 50% of the above rows. So it i am calling for 40% duty at 4000rpm/60% TPS I call for 20% DC at 4000rpm/50%TPS
4th row is 40% TPS and thats set to about 80% of the above row.
5th row is 30% TPS and all values are 10
bottom row is 20% TPS and all values are 0.


This give me a very smooth and linear throttle/power relationship.
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Old 10-23-2008, 10:19 AM   #3
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my table looks similar to pauls in respect to the TPS% and the amount of DC%.
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Old 10-23-2008, 11:39 AM   #4
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when did breaking loose at will become a bad thing? Makes sense though, and it'll save my tires.
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Old 10-23-2008, 12:55 PM   #5
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The AEM has a 3D boost *target* table, with TPS and RPM as the axes.
Then there is a boost target vs. duty table, then closed loop control.

My setup ends up being sort of similar to paul's, but with one difference.
I leave duty cycle to be ZERO from 0 to ~50% TPS. From 50-100% TPS I ramp duty cycle up. The idea is to have just the wastegate canister regulate boost up to half throttle, then target increasingly higher boost at larger throttle openings.
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Old 10-23-2008, 01:05 PM   #6
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Quote:
Originally Posted by johndoe View Post
when did breaking loose at will become a bad thing? Makes sense though, and it'll save my tires.
4th gear, off camber, closing radius / turn-4 at Hallett.
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Old 10-23-2008, 01:08 PM   #7
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here is how im handling it.

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Old 10-23-2008, 01:38 PM   #8
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Quote:
Originally Posted by johndoe View Post
What are you guys setting your duty targets to below full throttle? What are the benefits to running more or less duty at lower throttle positions. For instance, would running 100% duty cycle up to 4000 rpm and below 30 percent thottle help spool the turbo quicker at that rpm range or are you moving enough air then anyway that it's unnecessary? Or do you run less duty cycle at lower tps positions and why?
I run more duty at lower throttle positions.

I let my right foot control the boost.
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