wherein Savington discusses the health of his motor, and the specs of his new one
#1
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Been noticing low vacuum readings across the board recently. When I first went turbo, I would pull 22in.hg at idle, 25 on decel. Right now I'm doing 16-17 at idle and about 19 on decel. No power loss, still chatters 2nd, barks 3rd and 4th. I figured I was losing a cylinder, so I did a compression test. 200-190-185-185, so no major losses there (and not bad for a 150k motor with 20k of 13+psi in it). However, the 4th plug was significantly sootier than the others, and they were fresh plugs about a week ago. As soon as I get ahold of a leakdown tester I'm going to go ahead and do that, but perhaps I've got valve seals leaking?
And just for kicks, the specs of my planned build. Nothing fancy, going to try to keep it under $2k for the shortblock. Goal is to pick up a little power and a little response with more compression, and have a motor that will do 250whp stone reliably.
-Machine work (2mm over, deck) - $400ish? Haven't looked into it in my area.
-FM Weiscos, 9.5:1 compression, +2mm (if I can get them in that) - $600
-ETD rods - $450
-Boundary billet OPGs - $150
-ARP hardware - $250
-$500ish for head gasket, gaskets, seals, motor mounts, etc.
And just for kicks, the specs of my planned build. Nothing fancy, going to try to keep it under $2k for the shortblock. Goal is to pick up a little power and a little response with more compression, and have a motor that will do 250whp stone reliably.
-Machine work (2mm over, deck) - $400ish? Haven't looked into it in my area.
-FM Weiscos, 9.5:1 compression, +2mm (if I can get them in that) - $600
-ETD rods - $450
-Boundary billet OPGs - $150
-ARP hardware - $250
-$500ish for head gasket, gaskets, seals, motor mounts, etc.
#2
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Been noticing low vacuum readings across the board recently. When I first went turbo, I would pull 22in.hg at idle, 25 on decel. Right now I'm doing 16-17 at idle and about 19 on decel. No power loss, still chatters 2nd, barks 3rd and 4th. I figured I was losing a cylinder, so I did a compression test. 200-190-185-185, so no major losses there (and not bad for a 150k motor with 20k of 13+psi in it). However, the 4th plug was significantly sootier than the others, and they were fresh plugs about a week ago. As soon as I get ahold of a leakdown tester I'm going to go ahead and do that, but perhaps I've got valve seals leaking?
And just for kicks, the specs of my planned build. Nothing fancy, going to try to keep it under $2k for the shortblock. Goal is to pick up a little power and a little response with more compression, and have a motor that will do 250whp stone reliably.
-Machine work (2mm over, deck) - $400ish? Haven't looked into it in my area.
-FM Weiscos, 9.5:1 compression, +2mm (if I can get them in that) - $600
-ETD rods - $450
-Boundary billet OPGs - $150
-ARP hardware - $250
-$500ish for head gasket, gaskets, seals, motor mounts, etc.
And just for kicks, the specs of my planned build. Nothing fancy, going to try to keep it under $2k for the shortblock. Goal is to pick up a little power and a little response with more compression, and have a motor that will do 250whp stone reliably.
-Machine work (2mm over, deck) - $400ish? Haven't looked into it in my area.
-FM Weiscos, 9.5:1 compression, +2mm (if I can get them in that) - $600
-ETD rods - $450
-Boundary billet OPGs - $150
-ARP hardware - $250
-$500ish for head gasket, gaskets, seals, motor mounts, etc.
#6
Boost Czar
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22 ~hg.
not 22kPa.
I idle at 33-35kPa...I have a funny feeling I did my timing belt wrong when i replaced the pulley, I made the teeth jump so I had to redo it, always slightly lower vacuum than I was used to. I remember idling more around 29-28kPa.
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I idle at 33-35kPa...I have a funny feeling I did my timing belt wrong when i replaced the pulley, I made the teeth jump so I had to redo it, always slightly lower vacuum than I was used to. I remember idling more around 29-28kPa.
#7
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I have a log from last year showing idle MAP at 27-29kpa. Current is between 32-34kpa. :( If I get bored I'll open the valve cover and see if I jumped a tooth again. The motor burns about a quart of oil at every track day, but around town it burns virtually nothing. Mabye half a quart in 3000 miles.
#12
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Your oil consumption sounds pretty familiar too. When I spend a day tearing up the canyons or even just running down the freeway at extended high RPM, I'll go through about 1/2 quart in a couple of hours. OTOH, daily driving is about as you observed, maybe just a touch more (I might burn 1/4 per thousand.)
I try not to think about it. The motor will run as long as it feels like, and when it's finished, it'll let me know.
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#13
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Protip: Make sure the vacuum line feeding signal to both the MS and the boost gauge doesn't have a tear in it.
Replaced the plastic tee with a brass tee fitting and my idle/decel vacuum is 100% again. Idle 21-22, decel 24-25in.hg. Idle 27-28kpa.
Who knows how much boost my motor's been seeing recently
![Noob](https://www.miataturbo.net/images/smilies/noob.gif)
Who knows how much boost my motor's been seeing recently
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#14
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Protip: Make sure the vacuum line feeding signal to both the MS and the boost gauge doesn't have a tear in it.
Replaced the plastic tee with a brass tee fitting and my idle/decel vacuum is 100% again. Idle 21-22, decel 24-25in.hg. Idle 27-28kpa.
Who knows how much boost my motor's been seeing recently![](https://www.miataturbo.net/images/smilies/mad.gif)
![Noob](https://www.miataturbo.net/images/smilies/noob.gif)
Who knows how much boost my motor's been seeing recently
![](https://www.miataturbo.net/images/smilies/mad.gif)
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