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jwissler10

Wastegate adjustment

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I've been trying to get my truck to run slightly higher psi, I keep reading that smarty Catcher software does boost fooling but just did an experiment and found out it doesn't.

 

I ran my truck stock with same weight on same stretch of road and typically see 24psi max at 1500-2200 rpm under load.

 

Loaded catcher sw5 increased timing and torque same stretch of road and same weight, 24psi max at 1500-2200.

 

I then reloaded sw5 with same timing and torque and turned off the wastegate, easily hit 35psi and had to back out throttle.

 

I have an 05 with stock turbo, i'd like to run around 30-32 under load where today I'm only getting 24. Anyone know how I can accomplish this easily with UDC Pro?

 

 

As a side note I noticed my reported throttle percentage for each of the above, with catcher loaded it appears the same physical throttle position runs different reported percentages. I've continuously fought shifting issues and earlier in the week found significant difference between stock programming and when loading catcher. Stock programming shifts perfectly but reported throttle percentage is 10-15% higher than when catcher is loaded. It appears part of this may be that the tunes are adjusting what the truck computer interprets as throttle percentage, not sure if this affects wastegate or not?

 

Thanks for any help!

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The "box" tunes don't make your ecm interpret values from sensors differently than stock unless sensor scaling has been changed from stock. UDC pro doesn't allow for very many sensors scaling to be altered. Different maps have been changed by MADS to whatever it is they changed them to for each SW. Have you tried raising values in the charge air flow maps? Those maps act as the direct feed to the electronic wastegate. Although just raising those values where you want to raise them alone won't mean you will hit a higher boost target. Fueling and timing will also have an affect to the level of boost you will get.

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I wouldnt turn the waste gate off, i was checking drive pressure [psi PRE-turbo, exh side] and was getting up to 50~psi, i turned the waste gate off and see 70 psi! With the stock/moded stock turbo= leave the waste gate on. The exhaust housing is small.

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Thank you! I hadn't planned to leave it off when I saw how quickly it built pressure. I'd read through some posts that it might not make any difference so gave it a try just to see. I don't have head studs and don't want to do any damage, I just use this truck for heavy towing and am trying to keep egts down a few hundred degrees more than right now when pulling grades.

 

I modified the charge air flow maps to adjust limits to 30-32 and immediately noticed a difference. I haven't had a chance to pull a load with it yet but noticed my pressure went from average 24 to 28-30 which is basically what I was trying to accomplish. Unless one of you guys who knows way more than me corrects me, from what I know with stock turbo/head gasket the most I really want to run is 35psi and for most driving closer to 30. That's the target I've been shooting for.

 

Thank you for your help and info!

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So the Charge airflow tables are in lbs/min. How do I convert that to PSI for the wastegate?

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Drive pressure is usually around 2x boost pressure in a single turbo application I do believe

 

Stock turbo yes, except at light load. I have a moded stock turbo now & the highest ratio i see now @ WOT [@400~rwhp] is 1.3-1

At light to med load its close to 1-1

 

:burnout:

 

 

:thumbsup:

 

edit; This ^^^ is with the waste gate ON.

Edited by organicfarmer

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So the Charge airflow tables are in lbs/min. How do I convert that to PSI for the wastegate?

 

there is no direct conversion from lbs/min to psi. one is a flow rate measurement the other is a pressure measurement. There's a lot of variables there to convert that. Compressor map would help to know flow rates of the turbo at various engine speeds, etc.

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Stock turbo yes, except at light load. I have a moded stock turbo now & the highest ratio i see now @ WOT [@400~rwhp] is 1.3-1

At light to med load its close to 1-1

 

:burnout:

 

 

:thumbsup:

 

yes, thanks for adding the stock turbo portion lol

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I guess I'm at a loss on how to program those tables. Regular UDC just used a PSI table for the wastegate. How would I start tuning those tables if I wanted a max boost of about 30PSI?

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If you have a stock turbo, in the data logger graph put actual airflow, ambient pressure and actual boost pressure to kinda get an idea of airflow at different boost pressures. I would count on it being 100% accurate and remember that air flow will also depend on engine speed, fueling load, timing. Everything has an affect on everything. Our trucks don't actually measure air flow, it's calculated from air density, ambient pressure, temperature, lots of different variables

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