VVT and backpressure
Thank you!! I had a post about this issue and nobody responded about it.. yet.. Now I have the answer I needed.
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Joined: Mar 2004
Posts: 1,321
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From: MI
Originally Posted by Vic_Ferrari
Good post.
just to add onto what I posted, knowing the backpressure/ flow also helps in determining the antcipation of when to back off the VVT for a more seamless operation.
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Freshman User
Joined: Jun 2005
Posts: 45
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From: McKinney
Originally Posted by Whistle
WeKiwa-thanks for bringing this up. It's been bothering me a while too...
Maybe it would be nifty if one of the programmers took the exhaust back pressure reading into account with one of their performance tunes and someone offered a sensor that would work with your free-er flowing exhaust...rather than ignoring the sensor and making changes that keep it from working properly how about trying to work WITH the sensors we have and still feed the ECU all of the data it needs to run as well as possible?
-pretty much the same idea as the recalibrated MAF's all the NA folks get...this is just on the other side.
Maybe it would be nifty if one of the programmers took the exhaust back pressure reading into account with one of their performance tunes and someone offered a sensor that would work with your free-er flowing exhaust...rather than ignoring the sensor and making changes that keep it from working properly how about trying to work WITH the sensors we have and still feed the ECU all of the data it needs to run as well as possible?
-pretty much the same idea as the recalibrated MAF's all the NA folks get...this is just on the other side.
When I return home I'll dig a little deeper this time.The HP stuff should be waiting for me too so next weekend will be party time!
thanks to all for the info.
Back to tyeing things down and waiting for Dennis to LEAVE! My folks are freaked over this one. Me...I'm thinkig about the mods...
Wekiwa
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Joined: Mar 2004
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From: s.f. bay area
Originally Posted by Crash687
It is not a matter of backpressure for it to operate but more along the line of being able to monitor it. Pressure sensors have a sensitivity to them, if you trying to sense pressure changes lower than the sensitivity(larger exhaust, etc.), the computer won't recieve an acurate reading from the sensor. With a known orfice(size of the piping to the cat) and with a pressure reading, engineers can calculate how much volume is passing thru the turbo. Knowing the volume, the engineers can "map out" the volume /boost output curve(given output of a pump/fan at a know speed/pressure drop) of the turbo. They can better program the ECM to control the engine/turbo better (make it meet emissions).
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Im sorta dissaponted i didnt do some kinda track time with my truck, Pre Stright pipe..
The thing that i remember most with stock exhaust was the truck having the "sence" of more power, As in the way the power was deliverd when Stomping down.. It seemed to jerk you back Very hard.. Now it seems to be a more smooth power delivery. Plus with stock pipe and the SCMP it would bark the tires from 1st to 2nd, 2nd to 3rd and in cold weather 3rd to 4th... Now it wont do it at all... Plus a 3-4mpg decrease.. O well, at least it sounds Sexy..
The thing that i remember most with stock exhaust was the truck having the "sence" of more power, As in the way the power was deliverd when Stomping down.. It seemed to jerk you back Very hard.. Now it seems to be a more smooth power delivery. Plus with stock pipe and the SCMP it would bark the tires from 1st to 2nd, 2nd to 3rd and in cold weather 3rd to 4th... Now it wont do it at all... Plus a 3-4mpg decrease.. O well, at least it sounds Sexy..
