Part Throttle Full Boost ?
Originally posted by liquid7879
WTF are you talking about.....tps has nothing to do with full boost at part throttle...
WTF are you talking about.....tps has nothing to do with full boost at part throttle...
Originally posted by Jinu0808
Ok guys I have search the forum and read a couple post about this topic. I just want to know Do us EVO owners have to worry about this PTFB issue or no or is this just for WRX ? ? ?
I am getting confused with all the post can someone clear this up for me thank you.
Ok guys I have search the forum and read a couple post about this topic. I just want to know Do us EVO owners have to worry about this PTFB issue or no or is this just for WRX ? ? ?
I am getting confused with all the post can someone clear this up for me thank you.
In open loop control the ecu uses a map purely based on MAF readings. It does not look at or use at the O2 readings for any adjustment.
My point was that we(EVOs) do not get PTFB in closed loop control. We hit open loop at about 25-30% tp. Does that make any sense?
BTW... the whole thing regarding boost creep has to do with waste gate flow! It has nothing to do with JUST installing a MBC. The root of that problem is installing a freer flowing exhaust and the wastegate can't flow all that it should be able to flow and the excess goes throught the turbine wheel. It causes excess boost... aka boost creep.
Originally posted by Jinu0808
I think from others are saying as long as u dont go past 20 psi
doesnt matter what throttle you at you should be safe. But with a SAFC leaning out the fuel then I am not sure again.
I think from others are saying as long as u dont go past 20 psi
doesnt matter what throttle you at you should be safe. But with a SAFC leaning out the fuel then I am not sure again.
If you have the AFC set up correctly, it should not be adjusting while the ecu is in closed loop control!!
I think u should be fine......I know alot of people that are running fine with the AFC.
Its just when you raise the boost and gas and start modding your car beyond what your wastegate can regulate that you start to overboost.
Its just when you raise the boost and gas and start modding your car beyond what your wastegate can regulate that you start to overboost.
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From: My name is Ananda Robinson.Stupid people should be killed. i live in Maryland
Originally posted by liquid7879
WTF are you talking about.....tps has nothing to do with full boost at part throttle...
if your doing 50mph hour in 5 gear you can maintain your speed under 25% throttle.....now start accelerrating at the like 40% throttle.....yourt turbo is gonna spool wo being over 50% throttle and if you having your boost set to high it can jump to full boost way easier than if you were going 5 mph and then mashed in the gas to 80% in 1st gear;
yes you can over boost in higher gears with only part throttle causing a lean condition in your engine.
this has nothing to do with open loop or closed loop; it has to do with the amount of exhaust gas running through your turbo.....the ability of your wastegate regulating boost pressure and the lean condition is directly realted to how you have your AFR tuned in these conditions.
this is generally called boost creep; it is not as prevelant in the evos but yes it is possible in any turbo application.
search and read it has nothing to do with wrx or evo it is inherent to turbo motors; differnet designs have different amount of creep but it is still possible.
WTF are you talking about.....tps has nothing to do with full boost at part throttle...
if your doing 50mph hour in 5 gear you can maintain your speed under 25% throttle.....now start accelerrating at the like 40% throttle.....yourt turbo is gonna spool wo being over 50% throttle and if you having your boost set to high it can jump to full boost way easier than if you were going 5 mph and then mashed in the gas to 80% in 1st gear;
yes you can over boost in higher gears with only part throttle causing a lean condition in your engine.
this has nothing to do with open loop or closed loop; it has to do with the amount of exhaust gas running through your turbo.....the ability of your wastegate regulating boost pressure and the lean condition is directly realted to how you have your AFR tuned in these conditions.
this is generally called boost creep; it is not as prevelant in the evos but yes it is possible in any turbo application.
search and read it has nothing to do with wrx or evo it is inherent to turbo motors; differnet designs have different amount of creep but it is still possible.
You guys should really stop being combative when liquid post tech help in this forum. His points are always dead on helpful detailed and correct.
Originally posted by Turbo-Weapon
You guys should really stop being combative when liquid post tech help in this forum. His points are always dead on helpful detailed and correct.
You guys should really stop being combative when liquid post tech help in this forum. His points are always dead on helpful detailed and correct.
But... I didn't think that my posts were combative. I was just trying to educate and help out. Sorry if I offended anyone.
Last edited by AutoXer; Sep 28, 2003 at 04:56 PM.
Ok ok Yes there are several answers here and I dont think anyone was being combative.....
But just to summarize the topic.....
EVO's do not have the PTFB that are assosciated to the WRX's in respect to the closed loop operation of the ECU. This would be inherent to the design of their ECU
EVO's and other cars that are turbo charged can reach full boost at part throttle.....Due to boost creep. Boost creep is related to the turbo spinning faster than the wastegate can expunge excess exhaust gas to regulate boost poressure. This generally happpens when
. When this happens you can casue a lean condition....
To my understanding the topic was relavent however it may have not been specifically related to the wrx issue, which I may have misunderstood his question. I was giving him information that he would need to know if he started modding his car and got a fuel cut.......Which is caused by overboosting, which can be caused by boostcreeep. However, I have heard that the EVOS have not seen a major issue with this, even though it is possible.
But just to summarize the topic.....
EVO's do not have the PTFB that are assosciated to the WRX's in respect to the closed loop operation of the ECU. This would be inherent to the design of their ECU
EVO's and other cars that are turbo charged can reach full boost at part throttle.....Due to boost creep. Boost creep is related to the turbo spinning faster than the wastegate can expunge excess exhaust gas to regulate boost poressure. This generally happpens when
The root of that problem is installing a freer flowing exhaust and the wastegate can't flow all that it should be able to flow and the excess goes throught the turbine wheel. It causes excess boost... aka boost creep.
To my understanding the topic was relavent however it may have not been specifically related to the wrx issue, which I may have misunderstood his question. I was giving him information that he would need to know if he started modding his car and got a fuel cut.......Which is caused by overboosting, which can be caused by boostcreeep. However, I have heard that the EVOS have not seen a major issue with this, even though it is possible.
Originally posted by AutoXer
He's refering to the WRX PTFB problem. The problem is that the WRX ecu remains in closed loop control up until about 60% throttle position. In closed loop control the computer uses a map based on RPM(there may be others, feel free to correct me) for fuel deliverly but adjusts this map based on the O2 readings. It can only adjust to a certain point and then its maxed out. When it reaches this max it goes lean. Its flowing too much air for the particualr RPM.
In open loop control the ecu uses a map purely based on MAF readings. It does not look at or use at the O2 readings for any adjustment.
My point was that we(EVOs) do not get PTFB in closed loop control. We hit open loop at about 25-30% tp. Does that make any sense?
BTW... the whole thing regarding boost creep has to do with waste gate flow! It has nothing to do with JUST installing a MBC. The root of that problem is installing a freer flowing exhaust and the wastegate can't flow all that it should be able to flow and the excess goes throught the turbine wheel. It causes excess boost... aka boost creep.
He's refering to the WRX PTFB problem. The problem is that the WRX ecu remains in closed loop control up until about 60% throttle position. In closed loop control the computer uses a map based on RPM(there may be others, feel free to correct me) for fuel deliverly but adjusts this map based on the O2 readings. It can only adjust to a certain point and then its maxed out. When it reaches this max it goes lean. Its flowing too much air for the particualr RPM.
In open loop control the ecu uses a map purely based on MAF readings. It does not look at or use at the O2 readings for any adjustment.
My point was that we(EVOs) do not get PTFB in closed loop control. We hit open loop at about 25-30% tp. Does that make any sense?
BTW... the whole thing regarding boost creep has to do with waste gate flow! It has nothing to do with JUST installing a MBC. The root of that problem is installing a freer flowing exhaust and the wastegate can't flow all that it should be able to flow and the excess goes throught the turbine wheel. It causes excess boost... aka boost creep.
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