I am officially a real rx7 owner now

I was pulling out of a toll both/onramp that merges into a single lane before entering the expressway. I'm doing maybe 15-20. I look in my rearview and see this SUV fly through the sunpass lane with no apparent intent to slow down. So I redline 1st and 2nd and go WOT in 3rd until 70-75 at which point I shift into 4th and let off the the throttle. Right about this time I look in my rearview and see a car fast approaching ( in the slow lane mind you) so I floor it in 4th and I get to maybe 4-5k and I feel a slight shudder, then I'm slowing down....... No loud pop, no metalic ping, no audible popping just and little shake and done.

I roll to a stop and tried to restart - no dice. A normal engine turns over @ a couple hundred rpm and has compression bumps. Mine sounded like an empty blender and was turning over at prolly 1k or more (Interestingly the tach does not register at all while turning over at now). Street Diagnosis: No compression.

I was running about 14 psi on the stock turbo, AFR was mid 11's to low 12's on 87 octane. I have a V mount IC and ambient temps were roughly 70*.

I'd been running this setup for the past year, but I guess a 147k stock motor has to go at some point...


So what do you think was the cause of this little catastrophe?

 

detonation.

were you using colder plugs? the 87 octane fuel certainly didn't help. *safe* AFR for a turbo rotary is 11.4 at WOT.

 

That's what I suspected, but all the detonation stories I hear involve some kind of ping, pop, or audible indicator which was absent from this event.

Stock Plugs, Magnacore 8.5 wires. 87 didn't help, but there are people running 87 w/ high comp rotors, so that can't be an instant deal breaker.

I was still running stock timing maps which I think had a lot to do with it, I had planned to switch to boost based timing and use some more reasonable timing maps but I never found the time. Guess I'll have time now....

 

Yep..what fuel pump was it? 4th gear WOT puts everything to the test...

In the future...fix the timing (take around 10 degrees of advance out of it everywhere above 10psi) put 9's or colder in the leads, run the highest octane fuel available, and richen it up(more fuel=cooler)

Have your injectors cleaned/tested while the car is down, and I recommend doing some coolant jacket mods around the lead plug bosses on your replacement housings :]

 

FD pump running 40 psi base pressure 576cc primaries 750 cc secondaries.

The new timing maps will be in the car before I turn the key for the first time!
I've got a bunch of great condition 9's from short blocks I've torn down, so that's great.
I'll shoot for 10.5 @ 70* moving forward.
Primary injectors were cleaned late 2010' secondaries were installed brand new late 2011'

No time for a rebuild -- Picked up an S4 n/a block w/ 15k on a rebuild. Going to go 6 p-t and run 4x750 w/ the high comp rotor timing maps.