2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Engine blew up <sad face>

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Old Apr 12, 2009 | 10:49 AM
  #1  
PvillKnight7's Avatar
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Engine blew up <sad face>

The specs:

87 RX-7 TII
extened and widened secondarys, backcut runners
Exhaust ports widened and moved 2mm toward opening
RA apex seals with Mazda apex springs
new side seals and springs
corner seals with inserts removed
60-1 compressor with stock S5 exhaust housing and turbo manifold
stock S5 wastegate
Haltech E6K
PLX-M300 wideband

The engine was fully warmed. A/F under boost starts at 12.5 0-5psi, and drops to 11.5 by 10psi, 11.0 by 15psi. I put my foot down in 2nd and let the end the engine rev to 6500 when it detonated. The car hesitated hiccuped. I saw 11.XX on the wideband out of the corner of my eye. I wasn't watching the boost gauge but I have been having overboosting problems because the wastegate actuator arm sticks shut sometime. I fixed it before by lubing the arm with antisieze but the fix didn't last more than 3 months. Started sticking again yesterday but then stopped sticking. I'm guessing the boost spiked to 25psi and POP. Loss of power, no idle...my stomach hurts

I was 1 mile from my house so I limped it home.

I check my plugs bi-monthly. Clean them. Put them back in. I noticed the front rotor runs leaner than the rear. Front secondary injector dirty? Guess now I can test them.

I'm pissed I didn't replace the POS internal wastegate.

The good news is I have a spare S5 turbo engine with excellent housings and seals ready to go. The weather is getting warmer...2 hrs to get the engine out, 5 to rebuild, 3 to reinstall. There goes another weekend.

It's a street car I use for autocross when I have time. I need all the low end torque I can get...

Should I throw some S5 NA rotors in the new engine? I might not have a choice if my front rotor is trashed. I think I lost 2 RA seals because my compression is 0psi on the front.
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Old Apr 12, 2009 | 06:58 PM
  #2  
Frostycrowd's Avatar
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From: Nashville, TN
One thing I never understand is why no one ever uses a Fuel wall or overboost limit. I have haltech and when it goes past 16psi the injectors go 100% it has saved my engine countless times.

Sorry to hear regardless.
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