Over boost cutting in?
#1
Over boost cutting in?
Alright so I took my 95 running MS1 as a standalone, for its maiden voyage today. I made a set of mechanical det can headphones to hear for pinging and bought the full version of TS to use VE analize. So the majority of the day was spent driving around town in cruise, which the car does very well. It will roll into boost just fine but when I tried to really roll into it hard it would accelerate and begin a bucking followed by what the wideband read as 22.4. I look at my over boost protection and it was set to 7.5 psi, my wastegate is at 8 so believe that to be the problem. I always thought it cut spark and not fuel? although wouldn't 22.4 be too lean to run? afr's seem good rolling in, injectors are 440cc wrx's, ill look through my log to see if I can find the section of hard accel.
Last edited by Forrest95M; 04-03-2016 at 08:22 PM. Reason: typo
#12
Boost Czar
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spark cut?
that's retarded. Go back to Toyko Drift.
Both or Fuel Only, or Bust.
~3psi above boost target isn't bad, however. MS looks at the trend and if it *thinks* you're going to surpass the boost cut value, it will cut before you get there, so giving yourself a little headroom will prevent it from engaging when you dont want it to.
It's supposed to be there just in case something happens, like your actuator fails, otherwise learn how to tune so you don't have massive boost spikes.
that's retarded. Go back to Toyko Drift.
Both or Fuel Only, or Bust.
~3psi above boost target isn't bad, however. MS looks at the trend and if it *thinks* you're going to surpass the boost cut value, it will cut before you get there, so giving yourself a little headroom will prevent it from engaging when you dont want it to.
It's supposed to be there just in case something happens, like your actuator fails, otherwise learn how to tune so you don't have massive boost spikes.
#13
spark cut?
that's retarded. Go back to Toyko Drift.
Both or Fuel Only, or Bust.
~3psi above boost target isn't bad, however. MS looks at the trend and if it *thinks* you're going to surpass the boost cut value, it will cut before you get there, so giving yourself a little headroom will prevent it from engaging when you dont want it to.
It's supposed to be there just in case something happens, like your actuator fails, otherwise learn how to tune so you don't have massive boost spikes.
that's retarded. Go back to Toyko Drift.
Both or Fuel Only, or Bust.
~3psi above boost target isn't bad, however. MS looks at the trend and if it *thinks* you're going to surpass the boost cut value, it will cut before you get there, so giving yourself a little headroom will prevent it from engaging when you dont want it to.
It's supposed to be there just in case something happens, like your actuator fails, otherwise learn how to tune so you don't have massive boost spikes.
Now, if that is completely off base then teach me, dont insult me.
#20
Boost Czar
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,493
Total Cats: 4,080
In this scenario, not only is no fuel being injected, but your coils are still sparking away as the wheels spin the motor.
Yes, you don't want a lean condition under load. Lean conditions cause increased temperatures that can lead to auto-ignite, and moves the flame-front bringing peak pressures closer to TDC which can lead to knock.
With that being said, cutting fuel is the safest way to cut power to the motor. No Fuel, no Bang. No Bang, No Boom.
As soon as you cut fuel, you're no longer making any power, and the engine is no longer under any load. This is the typical fashion an OE manufacturer will implement a rev limiter or boost limiter.
When you cut spark only, you keep injecting fuel. So again, no bang; there's nothing to ignite the air/fuel mixture. But what happens when you spark again? **** ignites with a vengeance -- It's loud and destructive. It can damage your turbo, it will kill your cat, and it could lead to bent rods depending where the mixture ignites on the stroke. And there's the possibility you can straight up flood the motor and bend a rod on the compression stroke.
and yes, there's a need to be a dick. that's what i do!