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Old 10-26-2008, 05:27 PM   #1
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Default idle kpa?

so every body has said to tune idle for lowest kpa possible, which is cool. my question is what kind of numbers are you guys seeing and are you happy with the idle quality. I 've gotten a pretty steady 850 rpm idle at about 32-34 kpa. I can get a bit more vac. but the quality of the idle gets pretty crappy no matter what I try. so at what point have you guys called it good and stop futzing with it?
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Old 10-26-2008, 05:43 PM   #2
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Best idle IMO is running rich with lots of timing advance. I run ~11.0:1 AFR at 17* BTDC and idle ~26kPa and it's rock solid. But I have a lot of headwork that seems to contribute to the high vacuum. Still my idle sucks if I go over 12:1 AFRs and I loose vacuum.
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Old 10-26-2008, 06:01 PM   #3
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I tend to idle between 28-30 at 900-950 RPM. This is at about 17 BTDC and AFRs cycling through the low 14s to low 15s.

I really wouldn't go too crazy obsessing over idle MAP. It's just not that big a deal.

Pat, why the crazy-rich AFRs? Aren't you running HR code?
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Old 10-26-2008, 06:02 PM   #4
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I'm still waiting for my lc-1 to come back from innovate (defective) so I have no idea what afr I'm at. It is richened up a bit from the pnp base map though. and about 18* timing.
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Old 10-26-2008, 06:23 PM   #5
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Quote:
Originally Posted by Joe Perez View Post
I tend to idle between 28-30 at 900-950 RPM. This is at about 17 BTDC and AFRs cycling through the low 14s to low 15s.

I really wouldn't go too crazy obsessing over idle MAP. It's just not that big a deal.

Pat, why the crazy-rich AFRs? Aren't you running HR code?
You could say that. MS2E w/ 550's @ 62 PSI ~= 650cc. With the headwork I did the motor likes to run rich. I run 13:1 it gets a slight miss fire and it's not that strong at low RPMs. I idle 11:1 and it's butter smooth and loads of low end power. Might not make for the best economy but its torqy as hell down low.
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Old 10-26-2008, 09:42 PM   #6
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My idle manifold pressure is about 16kpa. Not sure why it is that low but, it was like that even before i unplugged the IAC.
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Old 10-26-2008, 09:48 PM   #7
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Originally Posted by wes65 View Post
My idle manifold pressure is about 16kpa. Not sure why it is that low but, it was like that even before i unplugged the IAC.
Holy ****! 16kpa is insane! You can't even enter a value that low in the VE talbe y axis. Are you sure your map sensor is working properly? With car off does it show atmospheric pressure, ie does your BARO meet MAP with engine not running? I've seen 2 of the MapDaddy sensors go bad which is what you are using in your 94/95 MSPNP.
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Old 10-26-2008, 09:57 PM   #8
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that's not low, that's a LOT of vacuum
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Old 10-26-2008, 10:00 PM   #9
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that's not low, that's a LOT of vacuum
Right, i mean, i dont know why the pressure is that low.

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Holy ****! 16kpa is insane! You can't even enter a value that low in the VE talbe y axis. Are you sure your map sensor is working properly? With car off does it show atmospheric pressure, ie does your BARO meet MAP with engine not running? I've seen 2 of the MapDaddy sensors go bad which is what you are using in your 94/95 MSPNP.
Hmm, i will go do a couple of logs right now.
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Old 10-26-2008, 10:04 PM   #10
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do you have a 4-bar sensor but are setup for a 250map?

16 x 2 = 32
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Old 10-26-2008, 10:08 PM   #11
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No need to log. Just open up Megatune. choose engine MAP gauge and Baro gauge. they should match when engine is not running.

My BARO here is 101. My map sensor reading got lower and lower. I finally switched it out when I as seeing 94 vs 101. A friend's did the same but got as low as 76. DIYAutotune replaced the sensors under warranty.
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Old 10-26-2008, 10:28 PM   #12
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haha you nailed it. It is showing 86. fwiw, here are the logs. You can see me go WOT, a guy in a civic tried to race lol.
Attached Files
File Type: zip map.zip (52.2 KB, 50 views)
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Old 10-26-2008, 10:29 PM   #13
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So get in touch with the guys at DIY and tell them your issue.
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Old 10-26-2008, 10:32 PM   #14
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So get in touch with the guys at DIY and tell them your issue.
Sounds good, Thanks! OP, sorry for inadvertently threadjacking.
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Old 10-26-2008, 11:31 PM   #15
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no sweat, it looks as though we've managed to discover a problem through discussion. ain't that what it's all about?
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Old 10-26-2008, 11:59 PM   #16
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Originally Posted by dynokiller90 View Post
no sweat, it looks as though we've managed to discover a problem through discussion. ain't that what it's all about?
Haha yeah, it sure is. Now hopefully, i can get my map sensor replaced.
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