Author Topic: Exhaust Brake  (Read 950 times)

Offline hakcenter

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on: May 26, 2015, 09:26:15 PM
Finally mounted my switches (not going to use a perf switch)

Code: [Select]
void exhaust_brake() {
  if (turbo_rpm < 55000 && turbo_rpm > 45000) { vane_position = map(turbo_rpm, 55000, 45000, 900, max_position); }
       if (turbo_rpm > 60000) { vane_position = vane_position - 50; }
  else if (turbo_rpm < 45000 && vane_position < max_position) { vane_position = vane_position + 25; }
  if (vane_position <= 900 && turbo_rpm < 60000) { vane_position = 900; }
  if (turbo_rpm > 21000 && turbo_rpm < 35000) { vane_position = map(turbo_rpm, 21000, 35000, 800, max_position); }
  if (turbo_rpm < 21000) { vane_position = 800; }
       if (vane_position <= min_position) { vane_position = min_position; }
  else if (vane_position >= max_position) { vane_position = max_position; }
}

I'll take pictures tomorrow.

AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.



Offline Rx7man

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Reply #1 on: May 26, 2015, 10:05:06 PM
Looks OK, though I'm not quite wrapping my head around how the exact logic works out while you're driving...

In my boostmap setup, I have a area of the map (High RPM, Low TPS) where I set the boost to 15PSI.. I call it the "auto brake" area... do you think it'll actually build that kind of boost without any fueling?

'94 dodge, Colt Cam, head worked, NV5600, 3.55's, SB clutch, Ford manual hubs w. hawk brakes, custom flatdeck, custom aluminum bumper, cab off restoration, totally new engine, Mahle pistons @19:1..HE351VE with 67mm turbine and 67x95mm compressor
440hp/1000 ft lb @ 2400 RPM


Offline hakcenter

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Reply #2 on: May 26, 2015, 11:17:23 PM
Looks OK, though I'm not quite wrapping my head around how the exact logic works out while you're driving...

In my boostmap setup, I have a area of the map (High RPM, Low TPS) where I set the boost to 15PSI.. I call it the "auto brake" area... do you think it'll actually build that kind of boost without any fueling?

The turbo is simply a centrifuge, so if it is spinning fast enough, absolutely will create boost. Whether that goes right out the exhaust is a different matter.

I'm yanking out a bit of the section and tightening it up.. it is working pretty well on my truck too bad I don't have a BP gauge.

I can tell you, 800-825 position does pretty much squat, where as once you get into the 900s small increments really changes how fast it slows your motor down.

AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.



Offline Rx7man

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Reply #3 on: May 27, 2015, 12:21:31 AM
In my initial test on my method, I'm going to try to not care at all where the vanes actually are at, and just use math to set them at the right position... without an exhaust pressure input it may be hard to do though

'94 dodge, Colt Cam, head worked, NV5600, 3.55's, SB clutch, Ford manual hubs w. hawk brakes, custom flatdeck, custom aluminum bumper, cab off restoration, totally new engine, Mahle pistons @19:1..HE351VE with 67mm turbine and 67x95mm compressor
440hp/1000 ft lb @ 2400 RPM


Offline hakcenter

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Reply #4 on: May 27, 2015, 05:00:26 PM
hum

AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.



Offline Rx7man

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Reply #5 on: May 27, 2015, 05:23:04 PM
Did you say you needed a TPS still?  maybe you can get one off an automatic tranny truck

'94 dodge, Colt Cam, head worked, NV5600, 3.55's, SB clutch, Ford manual hubs w. hawk brakes, custom flatdeck, custom aluminum bumper, cab off restoration, totally new engine, Mahle pistons @19:1..HE351VE with 67mm turbine and 67x95mm compressor
440hp/1000 ft lb @ 2400 RPM


Offline hakcenter

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Reply #6 on: May 27, 2015, 07:01:00 PM
Did any p pump cummins ever have a tps ?

AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.



Offline Rx7man

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Reply #7 on: May 27, 2015, 09:49:44 PM
I'm pretty sure the Auto tranny ones did.. the auto tranny VE pump trucks did like my dad's '92

'94 dodge, Colt Cam, head worked, NV5600, 3.55's, SB clutch, Ford manual hubs w. hawk brakes, custom flatdeck, custom aluminum bumper, cab off restoration, totally new engine, Mahle pistons @19:1..HE351VE with 67mm turbine and 67x95mm compressor
440hp/1000 ft lb @ 2400 RPM


Offline hakcenter

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Reply #8 on: May 30, 2015, 06:03:56 PM
Kinda fallen on this for the brake

Code: [Select]
void exhaust_brake() {
       if (turbo_rpm > 50000) { vane_position = 900; }
  else if (turbo_rpm < 50000 && turbo_rpm > 40000) { vane_position = map(turbo_rpm, 50000, 40000, 900, max_position); }
  else { vane_position = max_position; }
}

No back pressure, but unloaded truck, sounds pretty good. Really actually brakes very well.. probably make a video here in the future with all the goodies working.

AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.



Offline Rx7man

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Reply #9 on: May 30, 2015, 07:59:36 PM
cool.. looks simple enough :)

I can't wait to get all the stuff I need to do my truck, and actually get a chance to do real tuning rather than just theory.

'94 dodge, Colt Cam, head worked, NV5600, 3.55's, SB clutch, Ford manual hubs w. hawk brakes, custom flatdeck, custom aluminum bumper, cab off restoration, totally new engine, Mahle pistons @19:1..HE351VE with 67mm turbine and 67x95mm compressor
440hp/1000 ft lb @ 2400 RPM