All posts by Jeff

Misc.

Charge Air Temperature Rise with Boost Increases

There are a few bits of interesting data that I’ve recorded while measuring boost pressure for fixed wastegate duty cycles.  This is part of my effort to fine tune the KFLDRL numbers for the new wastegates that the TTE550’s use.

Each fixed wastegate duty cycle produces a different boost level.  The range of boost levels that were recorded in third gear are shown below.  Note: The recording in third at 10% was not long enough to make including the results worthwhile.

Boost Level for Fixed WG DC (TTE550 turbochargers)
Boost Level for Fixed WG DC (TTE550 turbochargers)

 

The chart above shows fixed WGDC’s of: 0%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 85%.

For each of these boost levels I also recorded the air temperature going into the turbocharger compressor, along with the temperature after exiting the compressor.  The approximate rise in temperature caused by the compression of the air for each boost level is shown below.

Air Temperature Rise for Boost Levels
Air Temperature Rise (degF) for Boost Levels

Note: This is an approximate rise due to the location of the air temperature sensor being slightly downstream from the turbocharger compressor outlet.  The air temperature exiting the turbocharger is likely higher than what is recorded due to cooling taking place in the charge pipe prior to the air passing over the temperature sensor.

Upgrade Work

Aquamist Anti-Surge Accumulator

I decided to pull this component out of a parts box and install it on my water-methanol injection system to see if it will help with smoothing out the fluid flow to the intake.

Aquamist Anti-Surge Accumulator "Water Shock"
Aquamist Anti-Surge Accumulator “Water Shock”

The part is called an anti-surge accumulator.  Aquamist offered it with the 2D system that I used to operate.  It helped to smooth the fluid supply from the race pump and was also supposed to help improve the flow rate from the pump.  I’ve noticed some oscillations in the reported flow rate and thought this might help to smooth the supply.  The Aquamist race pump had much lower flow capacity than most of the currently available pumps, so I’m not concerned with any flow rate increases that might come from using this part.  In fact I generally run the pump I have around 30-45% duty cycle and it cools well at that flow rate into a pair of 0.7mm Aquamist nozzles.

I’ve installed the ‘water shock’ after the pump and prior to the water flow sensor.

Water shock installed
Water shock installed

 

Tuning

WG Refinement

Matching 8 psi preload wastegates with the TTE550 sparked some discussion over the potential need to adjust the tune to accommodate this component pairing.

I’ve been satisfied with the responsiveness from the TTE550, but in the interest of finding out if “doing it the right way” would make any difference in the results I decided to undertake an effort to Calibrate the Tune’s KFLDRL table.  A detailed report on one persons attempt to do this is documented on the Nefmoto site and I’m using that as a starting point for my effort.

After setting CWMDAPP and KFLDRAPP appropriately I began by collecting 0% and 10% data.

 

0% N75DC
0% N75DC
10% N75DC
10% N75DC

 

An early observation is that I can likely refine where I am collecting data without adversely affecting the outcome.  Attempting to log boost data from 1000 to 6500 rpm in every gear is time consuming, risky, and not possible due to the speeds reached in 6th gear at 6500 rpm.  I’m not interested in conducting this work on a dyno so I am limited by conditions on public streets.

With the intent being to capture the maximum boost pressure achieved at a particular engine speed for each duty cycle setting, it looks as though I am able to use 6th gear to record from 1000-2500 rpm, 4th gear from 2750-4000, and 3rd gear from 4500-6500.  I believe this will produce ‘good enough’ results and reduce the amount of measurements I need to make.

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Some additional measurements, 20% and 30%.  These were made at ambient temperatures about 20 degF greater than the other two, which raises the question, should the fixed wastegate duty cycle boost pressure be recorded at the same temperature?  I would think so, but then if it did matter what does that say for the KFLDRL results that are being tabulated and how they hold across different temperature ranges.

20% N75 DC
20% N75 DC
30% N75 DC
30% N75 DC

These latest results are prompting me to also drop taking measurements in 4th gear since I’m not seeing any value added from those readings.

I will be logging 3rd and 6th gears with only the <3000 rpm region of the 6th gear data being used.

Shown below are the composite 3rd gear results thus far.  Note: The 10% DC pull was very short.

0-30% Fixed WG Duty Cycle Boost Readings
0-30% Fixed WG Duty Cycle Boost Readings