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Old 03-16-2008, 11:48 PM   #1
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Default Over boost protection

A short MS story you may find amusing. So with my 550cc RX-7 injectors in I decide to adjust the waste gate to increase the boost from 5 psi to 6-7 psi. After the adjustment I decide to take it out for a quick run to see if the tension was right. While driving up a hill I go to WOT (watching the O2 gauge) and the car accelerates. Feels like a bit more power. I let off the throttle a bit, reapply to WOT, and about 5500 rpm the car starts lurching in a bad way. WTF?

So I let off, and bring the car to a stop to check the log files. Everything looks good right up until the lurching starts, at which point MAP and PW swing up and down as expected from the lurching. But everything looks good right up to that point, including the boost level. OK what caused this to happen? Hmmm... Oh wait, what do I have the over boost protection set to?

Oh yeah, set to 6 psi I forgot to raise it when I adjusted the wastegate and it was coming on, causing the lurching. Moral of the story... over boost protection works! I tested by accident.

I'm really getting to like the MS/Megatune data logging feature.
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Old 03-17-2008, 12:03 AM   #2
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i have done the same thing before. i was like WTF is wrong with the car? oh, overboost
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Old 03-17-2008, 12:09 AM   #3
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I "tested" it st 16 psi SURPRISE! The other dday when I put an extra spring on the WG.....it works.
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Old 03-17-2008, 03:22 AM   #4
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I'm gonna use overboost protection in combination with the rev limiter to set a sort of "valet mode". Just think about only being able to hit 1 psi and rev only to 5000 rpms...
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Old 03-17-2008, 10:21 AM   #5
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Quote:
Originally Posted by Bryce View Post
I'm gonna use overboost protection in combination with the rev limiter to set a sort of "valet mode". Just think about only being able to hit 1 psi and rev only to 5000 rpms...
I wouldnt want a valet revving my car to 5k rpm even without boost. If I ever have to hand my car over to anyone, rev limit is going to be set to 1500.

I actually wanted to use the launch mode as a sort of valet mode. Flip a hidden switch and it locks the rpm's to a preset maximum.
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