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Cruising EGT?

Vais01
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Vais01

Vais01

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Well I have been curious just to see what an average EGT range for the VP powered trucks. I run between 600-700 pre-turbo anywhere from 55-75 MPH usually at 0-3 psi of boost.

My truck has 100hp(7x.009 SAC) injectors, a 62/68/14 wastegated turbo, factory air box with a modified opening, 285/70R17, low stall converter, done rite valve body and 3.54 rear gears.

Like I said just curious to see what people average.

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Vais01

Vais01

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+50 HP injectors, HX35 Turbo, 3" Exhaust, Edge Comp 5x3

55 MPH - 550*F

65 MPH - 650*F

75 MPH - 750*F

Assuming flat ground, no head or tail winds, no cargo or trailers.

I am going to make the assumption you run RV275 injectors.

Nice and cool at 55 MPH.

What boost are you making while cruising?

Not exactly sure why as long as I am on flat ground any speed from 55-75 is the same EGT range. Maybe it's because I drive around with 0-3 PSI of boost.

Edited by Vais01
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Mopar1973Man

Mopar1973Man

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I am going to make the assumption you run RV275 injectors.

Nice and cool at 55 MPH.

What boost are you making while cruising?

Not exactly sure why as long as I am on flat ground any speed from 55-75 is the same EGT range. Maybe it's because I drive around with 0-3 PSI of boost.

 

No. Not a RV275 (+40 HP) its a +50 HP very small difference but its there...

 

55 MPH - 1-2 PSI

65 MPH - 3-5 PSI

75 MPH - 5-8 PSI

 

This why I never upgraded exhaust majority of my engine time is well below 10 PSI cruising. Towing now is a different story but I don't tow fast either so my boost and EGT's are still rather lowish. Climbing a grade is a different story but still very very controllable.

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Vais01

Vais01

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No. Not a RV275 (+40 HP) its a +50 HP very small difference but its there...

 

55 MPH - 1-2 PSI

65 MPH - 3-5 PSI

75 MPH - 5-8 PSI

 

This why I never upgraded exhaust majority of my engine time is well below 10 PSI cruising. Towing now is a different story but I don't tow fast either so my boost and EGT's are still rather lowish. Climbing a grade is a different story but still very very controllable.

I have an upgraded exhaust and believe me it makes no difference other than everything after the down pipe is stainless steel.

I'm surprised that at 75 MPH I run lower EGT's with larger injectors and roughly 3 PSI of boost. May be a sweet spot.

The only grade I have pulled is a long bridge in Sulphur, Louisiana kept the speed at 70 throughout the pull and the EGT's never went over 900 and the boost kept creeping up. With my old VGT setup I would easily go into 1000 until I lifted the throttle.

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Vais01

Vais01

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I sit right at 600-650 at 55

700-750 at 65

800-850 at 75

Almost the exact same EGT's I had using the HE351VE. What are your boost levels at those cruising speed?

I'm willing to bet your turbo transient response times are awesome.

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Me78569

Me78569

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depends I have a couple different profiles that are assignable via an in-cab pot.  I can choose from 3 curves currently low mid and high

 

Low or towing curve will put me at atleast 5 psi at 55 unloaded.  Loaded I am sure that would be closer to 10-15psi  ( no extra fuel run except for the injectors)

 

Mid curve I see ~3psi at 55 unloaded  ( fueling should be set to lvl 2 on the quad or canbus plus timing only)

 

High curve performance mode I see 0 psi at 55.  ( I can runt he quad turned up on this mode)

 

 

Keep in mind my curves are based on the amount of fuel I am putting in rather than how much psi I want.  The tuning of the turbo works better if you do this.  So even though I have 0psi cruising at 55 in Perf mode, If I step on it the fueling I have will light the turbo quick and build to the max boost WITHOUT overspinning.   If I use the towing curve with all my fuel turned up it does make for a fun ride, however you push the turbo   WAY out of it's map, I would be blowing hot air by 2000 rpm.

 

 

I am able to do this since I am watching my TPS values and adjusting the vanes from there.   

// TPS_range calc process
     if (ThrottlePosition <= 25) {TPS_low = true;} else {TPS_low = false;}
     if (ThrottlePosition <= 45 && ThrottlePosition > 25) {TPS_midlow = true;} else {TPS_midlow = false;} //{TPS_range = 0;}// watches throttle input to increase vane position.  Vane position mapping is based on low throttle input. 
     if (ThrottlePosition <= 70 && ThrottlePosition > 45) {TPS_mid = true;} else {TPS_mid = false;} //{TPS_range = 20;}
     if (ThrottlePosition > 70)  {TPS_high = true;} else {TPS_high = false;} //{TPS_range = 40;}

     if (TPS_low) {TPS_range = 0;} //supports low throttle cruise. if under %25 don't change vanes
     if (TPS_midlow){
      if ( BoostPressure < 5) {TPS_range = -40;} //it will try and spool the turbo if tps is 25><45 - numbers decrease vane size
      else if ( BoostPressure < 10) {TPS_range = -20;}
      else {TPS_range = 0;}
     }
     if (TPS_mid){
      if (BoostPressure < 10) {TPS_range =  -20;} 
      else if (BoostPressure < 20) {TPS_range = 0;}
      else {TPS_range = 20;}
     }

as an example you can see that I am making TPS_range range between one cm smaller , -40, to one cm bigger ,40.

 

Then in my vanes calc section I add that TPS_range value

else if (turbo_rpm < lit_rpm) { AntiBark = false;
          vane_position = map(turbo_rpm, curve_rpm[4], lit_rpm, turbo_curve[3]- TPS_range, turbo_curve[4] - TPS_range);}

so if I am cruising with turbo rpms at 50,000 and I step on it the vanes will actually close some if boost if lower than 10psi. However if boost is up above 30 psi I will open the vanes some.

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Vais01

Vais01

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depends I have a couple different profiles that are assignable via an in-cab pot.  I can choose from 3 curves currently low mid and high

 

Low or towing curve will put me at atleast 5 psi at 55 unloaded.  Loaded I am sure that would be closer to 10-15psi  ( no extra fuel run except for the injectors)

 

Mid curve I see ~3psi at 55 unloaded  ( fueling should be set to lvl 2 on the quad or canbus plus timing only)

 

High curve performance mode I see 0 psi at 55.  ( I can runt he quad turned up on this mode)

 

 

Keep in mind my curves are based on the amount of fuel I am putting in rather than how much psi I want.  The tuning of the turbo works better if you do this.  So even though I have 0psi cruising at 55 in Perf mode, If I step on it the fueling I have will light the turbo quick and build to the max boost WITHOUT overspinning.   If I use the towing curve with all my fuel turned up it does make for a fun ride, however you push the turbo   WAY out of it's map, I would be blowing hot air by 2000 rpm.

 

 

I am able to do this since I am watching my TPS values and adjusting the vanes from there.   

// TPS_range calc process
     if (ThrottlePosition <= 25) {TPS_low = true;} else {TPS_low = false;}
     if (ThrottlePosition <= 45 && ThrottlePosition > 25) {TPS_midlow = true;} else {TPS_midlow = false;} //{TPS_range = 0;}// watches throttle input to increase vane position.  Vane position mapping is based on low throttle input. 
     if (ThrottlePosition <= 70 && ThrottlePosition > 45) {TPS_mid = true;} else {TPS_mid = false;} //{TPS_range = 20;}
     if (ThrottlePosition > 70)  {TPS_high = true;} else {TPS_high = false;} //{TPS_range = 40;}

     if (TPS_low) {TPS_range = 0;} //supports low throttle cruise. if under %25 don't change vanes
     if (TPS_midlow){
      if ( BoostPressure < 5) {TPS_range = -40;} //it will try and spool the turbo if tps is 25><45 - numbers decrease vane size
      else if ( BoostPressure < 10) {TPS_range = -20;}
      else {TPS_range = 0;}
     }
     if (TPS_mid){
      if (BoostPressure < 10) {TPS_range =  -20;} 
      else if (BoostPressure < 20) {TPS_range = 0;}
      else {TPS_range = 20;}
     }

as an example you can see that I am making TPS_range range between one cm smaller , -40, to one cm bigger ,40.

 

Then in my vanes calc section I add that TPS_range value

else if (turbo_rpm < lit_rpm) { AntiBark = false;
          vane_position = map(turbo_rpm, curve_rpm[4], lit_rpm, turbo_curve[3]- TPS_range, turbo_curve[4] - TPS_range);}

so if I am cruising with turbo rpms at 50,000 and I step on it the vanes will actually close some if boost if lower than 10psi. However if boost is up above 30 psi I will open the vanes some.

 

 

 

Looking good. Keep up the tuning. Your 850 EGT is a little warm compared to others.

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