scoobiesport
Member
I think I may have to do with fuel delivery but I am not an expert. It is the same way with my WRX and my 280Z. Right about 7/8th throttle and I get the best performance...
WTF is up with my MSP?? It's faster at partial throttle the it is at WOT.
- Thread starter CustomMSP
- Start date
Exactly. Many other turbo'd cars have this same "problem". It's not a problem, at all, it's just how the turbo works on these particular setups.scoobiesport said:
Although, I said this a while back and everyone ignored my comment.
This has nothing to do with the flash, stumble, hesitation, clunk, rattles, blown subs, or screwy stock headunits.GET THE FLASH!
Check the ECU flash thread - you get some 10-15whp more at mid-range RPM's after the flash - and while tyhe hesitation doesn't completely go away, there is a Large Difference in part-throttle operation. It gets much smoother than pre-flash - and a lot of the enging bucking also goes away. Yes, it's not perfect, but it's hella lot better than pre-flash. I do notice some flat spots in acceleration, but nowhere near what they were (probably 90% cured). Accelerating onto the freeway on the local lo-ong uphill onramp (WOT 1-2-3, ease into 4, decelerate into traffic) is unbelievably-much better.
The above represents my humble opinion on a stock powertrain, some 900 miles post-flash. Your mileage may vary. Side effects include wide grinning, passenger flushing, and grab-handle awareness, and do not occur in all cases. See your doctor for details, your mileage may vary.
Check the ECU flash thread - you get some 10-15whp more at mid-range RPM's after the flash - and while tyhe hesitation doesn't completely go away, there is a Large Difference in part-throttle operation. It gets much smoother than pre-flash - and a lot of the enging bucking also goes away. Yes, it's not perfect, but it's hella lot better than pre-flash. I do notice some flat spots in acceleration, but nowhere near what they were (probably 90% cured). Accelerating onto the freeway on the local lo-ong uphill onramp (WOT 1-2-3, ease into 4, decelerate into traffic) is unbelievably-much better.
The above represents my humble opinion on a stock powertrain, some 900 miles post-flash. Your mileage may vary. Side effects include wide grinning, passenger flushing, and grab-handle awareness, and do not occur in all cases. See your doctor for details, your mileage may vary.
I've gotten my car flashed twice supposetly, and I don't feel any difference for some reason. It's still slower after 4k rpm most of the time...but sometimes it actually pulls hard all the way to redline. The car has been much better since I got a downpipe a month ago, but still doesn't feel like it's performing at 100% about half the time. When I ran my FPR kit I was using the wrong vac line. The kit actually made my car run like s*** sometimes right at about 3k rpm and on. So I took it off at that point and it's been much better since, but still doesn't feel like some other MSPs I drove at about tthe same amount of boost and flashed. I don't know, I could have messed something up by installing the FPR kit maybe not, maybe I'm just super anal about my car and imagening s*** here. In the end I think all this has to do with the "self learing/adapting" ecu our cars have. This fuker has a brain of it's own "AI" lol One day the car runs very good, the next it runs like s***. Other than that I love my MSP
Well I am gunna try driving another MSP. The first one I ever drove felt faster then the one I bought. I remember driving the one I bought about a week after I drove the first one and thought that it felt weaker. I will find out maybe tomorrow since my dad works at the dealer and we car pool.
I dont' know if this apply's to the MSP, but when I had my VW 1.8T, it actually backed off the boost at higher RPM's because the tiny-little turbocharger couldn't spin fast enough to maintain that boost level. Our cars have pretty tiny turbos as well, is it possible that this is the case with our cars? I know the 1.8T has a computer controlled wastegate, and I don't think the MSP does, but I could be wrong... it's happened before. (but don't tell anyone! )
)My car is flashed and I think it feels slower at WOT when accelerating. I don't have an A/F guage so I thought maybe for some reason I was getting overly rich fuel or maybe even the fuel cut. I suppose if it was fuel cut I would know for sure.
I've had my MSP flashed, and it definitely feels like it pulls harder at partial throttle than WOT. I hate it. After 4000 RPM, the power feels like it crashes through the floor, down to nothing. The only thing the flash seemed to do for my MSP was to smooth out the acceleration before the car reaches 4000 RPM. I didn't feel any particular increase in power. I just wasn't jerked around in my seat as much. Blah.
I'm finally installing my Injen CAI next week. Not sure how much that'll help, if at all. And I'm probably going to purchase a downpipe without any cats -- one of the small advantages of living in Central PA, no emissions tests for passing inspection! I'm just hoping that those mods will help free things up a bit and actually get my MSP to frickin' MOVE.
I'm also taking my MSP back into the original dealership, where I purchased it, over my Thanksgiving break. I have a huge-ass list of s*** I want them to look at. And if, after I take it in there and the car still feels crappy, I'll b**** my head off. Because my MSP, without a doubt, does NOT feel the same as it did when purchased. And that's bulls***.
I'm finally installing my Injen CAI next week. Not sure how much that'll help, if at all. And I'm probably going to purchase a downpipe without any cats -- one of the small advantages of living in Central PA, no emissions tests for passing inspection! I'm just hoping that those mods will help free things up a bit and actually get my MSP to frickin' MOVE.
I'm also taking my MSP back into the original dealership, where I purchased it, over my Thanksgiving break. I have a huge-ass list of s*** I want them to look at. And if, after I take it in there and the car still feels crappy, I'll b**** my head off. Because my MSP, without a doubt, does NOT feel the same as it did when purchased. And that's bulls***.
The reason there is more power at partial throttle than full throttle is because of the ECU's fuel delivery system. At WOT, the ECU basically dumps the maximum amount of fuel it can for that particular engine speed. This is called "open loop" operation because it ignores feedback from the O2 sensor. At partial throttle, the ECU is still operating in "closed loop" mode, where it injects the appropriate amount of fuel based on engine speed and O2 sensor readings. So at partial throttle, there is a more stoichiometric mix in the combustion chamber, providing a quicker, more complete burn, which ultimately results in more power.
This practice is the same for just about every car I've heard of, turbo or not. The intention is to avoid detonation at WOT by making the fuel mixture as rich as possible. This is not a problem or anything the dealer can address. It is a common design for fuel injection. It merely requires a little more attention to detail when learning how to drive your car fast.
The flash should not affect this at all, as the ECU is still in open loop operation at WOT. For information on the flash, look here:
http://www.msprotege.com/vbb230/showthread.php?s=&threadid=30901
I hope this alleviates any confusion.
-Josh
This practice is the same for just about every car I've heard of, turbo or not. The intention is to avoid detonation at WOT by making the fuel mixture as rich as possible. This is not a problem or anything the dealer can address. It is a common design for fuel injection. It merely requires a little more attention to detail when learning how to drive your car fast.
The flash should not affect this at all, as the ECU is still in open loop operation at WOT. For information on the flash, look here:
http://www.msprotege.com/vbb230/showthread.php?s=&threadid=30901
I hope this alleviates any confusion.
-Josh
Last edited:
I'm not sure where I learned it, exactly. Mostly from just talking to other knowledgeable car people. As far as open- and closed-loop - those are terms used to describe different types of control systems. I've had a few classes in analog and digital control systems, so that's where my background comes from.
Basically, an open loop system is anything that generates an output directly from an input, regardless of other factors. A closed loop system incorporates some sort of feedback to change the input based on how the output is responding.
In the case of fuel delivery, the input is the engine speed, and the output is the amount of fuel injected. This would be open-loop operation if there was nothing else considered. Closed-loop operation would incorporate some sensor feedback (O2, MAF, etc.) to modify the amount of fuel delivered. This results in a more accurate fuel mixture because the computer is constantly adjusting the amount of fuel based on external conditions.
Overall, it's difficult to explain, but perhaps this leads you in the right direction.
-Josh
Basically, an open loop system is anything that generates an output directly from an input, regardless of other factors. A closed loop system incorporates some sort of feedback to change the input based on how the output is responding.
In the case of fuel delivery, the input is the engine speed, and the output is the amount of fuel injected. This would be open-loop operation if there was nothing else considered. Closed-loop operation would incorporate some sensor feedback (O2, MAF, etc.) to modify the amount of fuel delivered. This results in a more accurate fuel mixture because the computer is constantly adjusting the amount of fuel based on external conditions.
Overall, it's difficult to explain, but perhaps this leads you in the right direction.
-Josh
