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MAP kpa after EFI install

 
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Ozzie  



Joined: 12 Mar 2005
Posts: 4415
Location: Townsville, Qld. Australia

PostPosted: Tue Jun 16, 2015 4:58 pm    Post subject: MAP kpa after EFI install Reply with quote

The car is running and I'm now starting the tuning process after a Microsquirt fuel only install.
This is a 125 HP vehicle and the best I can do on the MAP is 47kpa absolute at 13.5 AFR at 950 rpm.
I think this equates to 16" hg.
Am I correct?

Messing around with the VE table and waiting on a rs232/USB adaptor so I can tune on the road. The table generated appears to be ok after changing a few figures.
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leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Tue Jun 16, 2015 9:04 pm    Post subject: Reply with quote

not quite right...
check your ign advance, IIRC the stock setup (86.5mm bore and stock cam 9.3:1comp) should yield somewhere around 17"-20, might be a vaccum leak otherwise...

see here:
http://www.924board.org/viewtopic.php?p=246564&sid=0d8b8ee62399fb939583a020025c4f4c

calculator here:
http://www.endmemo.com/sconvert/kpainhg.php
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Ozzie  



Joined: 12 Mar 2005
Posts: 4415
Location: Townsville, Qld. Australia

PostPosted: Tue Jun 16, 2015 9:23 pm    Post subject: Reply with quote

Using your calculator I should get nearly 60kpa to get 17" which is wrong.
60 kpa is worse vacuum than the 47 kpa I get now.

0kpa = 30 inches of mercury not 100 kpa.
ATM = 100 kpa

Doing some research I think I need some ign advance.
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Last edited by Ozzie on Tue Jun 16, 2015 9:57 pm; edited 1 time in total
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leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Tue Jun 16, 2015 9:49 pm    Post subject: Reply with quote

yeah sorry, calc is naff, did you see RC's post at the bottom... 45kpa equates to 16.63"hg in engine terms, so bees dick away from 17"-20"hg range...
i'd still check advance timing and check for leaks, but it's certainly driveable according to raceboy's comment...
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Ozzie  



Joined: 12 Mar 2005
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Location: Townsville, Qld. Australia

PostPosted: Tue Jun 16, 2015 9:57 pm    Post subject: Reply with quote

Yes- think I need to advance the timing a bit more.

will get the light out tomorrow
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Ozzie  



Joined: 12 Mar 2005
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Location: Townsville, Qld. Australia

PostPosted: Wed Jun 17, 2015 8:31 am    Post subject: Reply with quote

this is probably a better scale using KPA abs where 0 kpa = 100% vacuum
http://www.engineeringtoolbox.com/vacuum-converter-d_460.html
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Raceboy  



Joined: 01 Mar 2004
Posts: 2292
Location: Estonia, Europe

PostPosted: Wed Jun 17, 2015 2:01 pm    Post subject: Reply with quote

40-50 kpa at idle with 924 is quite normal. I have had exactly this on pretty much all 2.0 engines I have installed EFI on. On my Gulf there has been ~70 kPA due to ITB's lol
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morghen  



Joined: 21 Jan 2005
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Location: Romania

PostPosted: Wed Jun 17, 2015 5:56 pm    Post subject: Reply with quote

I have -0.5bar(below atmosferic) with a cold engine and -0.6bar with a warm engine on my red 924 turbo. That sounds about the same what you have.
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Ozzie  



Joined: 12 Mar 2005
Posts: 4415
Location: Townsville, Qld. Australia

PostPosted: Wed Jun 17, 2015 7:25 pm    Post subject: Reply with quote

Adjusted the timing today and is now at 42kpa (-58kpa)
Will take it for a run as I think it is too advanced and might ping a bit.
I set the Map so the gauge read the current atm pressure.
Low setting specs are hard to get for a GM 1 bar MAP.
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