Ej20g Compression numbers?

Bookem74 · 07-28-2012, 01:44 PM

I did do a quick search but only found numbers around 170 for a test turning more than 300 rpms, 150 psi being normal and guys with issues where numbers where down severely. I have the opposite, I had my enigne out to install uel header with a solid up pipe, turbo coolant hose, turbo oil feed banjo bolt and copper seals, I figured I would do a compression test just so I know the numbers and if anything happens in the future I have a baseline number. I do have a good battery and had a charger on at low charge but my numbers 180 for all four. I bought the engine from Jhot back in '09 with 65k km and have put on roughly 10k miles since.

Has anyone else seen numbers like this? Did the previous owner replace pistons? I'm not worried just wondering if these are normal for stock.

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simer1228 · 07-28-2012, 07:32 PM

previous owner could've replaced the pistons with higher CR pistons... but I think carbon build up is more likely. Do you know what A/F ratios you're running?

Bookem74 · 07-28-2012, 08:33 PM

I'll double check the afr when I get it running this next week.

Bookem74 · 08-02-2012, 10:56 AM

Reading off my AEM wb, afr is 14.3 at idle and normal cruising does richen up when on throttle like normal but at wot is getting to 11.5. When I'm getting on it and let off does go into the upper 10's just for a split second then leans way out and maxes out the gauge over 17 then the three dashes appear.

Spark plugs looked great when I was doing compression test.

Engine is an early 96, z4 ecu with some sort of chip that was installed by previous owner as well.

07-28-2012, 01:44 PM	#1
Bookem74 Scooby Newbie Member#: 174481 Join Date: Mar 2008 Chapter/Region: MWSOC Location: Moorhead, Mn Vehicle: 98 Legacy GT-T	Ej20g Compression numbers? I did do a quick search but only found numbers around 170 for a test turning more than 300 rpms, 150 psi being normal and guys with issues where numbers where down severely. I have the opposite, I had my enigne out to install uel header with a solid up pipe, turbo coolant hose, turbo oil feed banjo bolt and copper seals, I figured I would do a compression test just so I know the numbers and if anything happens in the future I have a baseline number. I do have a good battery and had a charger on at low charge but my numbers 180 for all four. I bought the engine from Jhot back in '09 with 65k km and have put on roughly 10k miles since. Has anyone else seen numbers like this? Did the previous owner replace pistons? I'm not worried just wondering if these are normal for stock. * Registered users of the site do not see these ads.

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07-28-2012, 07:32 PM	#2
simer1228 Scooby Newbie Member#: 171039 Join Date: Feb 2008 Chapter/Region: NESIC Location: Randolph, Vermont Vehicle: 99 RSTi TypeRA LTD Black Diamond Pearl	previous owner could've replaced the pistons with higher CR pistons... but I think carbon build up is more likely. Do you know what A/F ratios you're running?

07-28-2012, 08:33 PM	#3
Bookem74 Scooby Newbie Member#: 174481 Join Date: Mar 2008 Chapter/Region: MWSOC Location: Moorhead, Mn Vehicle: 98 Legacy GT-T	I'll double check the afr when I get it running this next week.

08-02-2012, 10:56 AM	#4
Bookem74 Scooby Newbie Member#: 174481 Join Date: Mar 2008 Chapter/Region: MWSOC Location: Moorhead, Mn Vehicle: 98 Legacy GT-T	Reading off my AEM wb, afr is 14.3 at idle and normal cruising does richen up when on throttle like normal but at wot is getting to 11.5. When I'm getting on it and let off does go into the upper 10's just for a split second then leans way out and maxes out the gauge over 17 then the three dashes appear. Spark plugs looked great when I was doing compression test. Engine is an early 96, z4 ecu with some sort of chip that was installed by previous owner as well.