Howdy everyone. Looking to pick your brain for some wisdom and input. I have an 88 mazda rx7 turbo II, and I'm pretty sure I killed it today. I was at full boost, wide open throttle, and the car bucked hard before progressively harder to keep moving. Idle became very rough, and it felt like it was missing severely, requiring great effort and lower gears to maintain speed.

I removed the intercooler and found no loose or blown connectors or hoses. Car would not truly idle on its own unless I was giving it gas. When cranking the car, it sounds abnormal. I took a video I will reference here at the end.

Modifications are an s5 turbo and manifold, racing beat turbo back exhaust, walbro pump, rtek modified ecu and full emissions block off.

Here is a link to the brief video; https://youtu.be/wfek8G4cju0

I'll be doing a compression test tomorrow, but I'm not optimistic. Any thoughts or ideas are welcome.

 

Doesn't sound good, but the compression test will tell the tale.

Sux man

 

Yep, it's done.

Fix whatever caused the engine to blow and then rebuild it.

 

I'm more concerned with what caused it than the actual rebuild itself. I have no desire to spend the time and money to have it happen again.

 

Making the link easier to click.

 

You are definately running on one rotor but a really strong engine would be able to do that (I got a youtube video of it).

Hopefully you just lost an injector, which is what happened to me, but you really need to do a compression test. I thought I either lost my leading coil or the engine died.

My video of running on one rotor...

 

lemme know if you need a motor

i can hear the dead chambers during crank though, that motor is doa.

 

Hopefully it is something simple, but if not I'm sorry to hear about your problem. If the compression is gone in one of the rotors, then it very well could be a case of "boost in, apex seals out".

If that is the case, you need to give a lot more details. What was your boost level with the stock S5 parts? What was your target a/f @ WOT with the tuning in the Rtek? Are you using stock sized injectors? What octane gasoline were you running? Do you have a gauge(s) to monitor fuel pressure, intake temperature and exhaust temperature as well as a readout from a WBO2 sensor - if so what were they reading? Did you happen to notice the water temp gauge reading?

If things were not just right, you would have had denotation. If it was bad enough the rotor faces will show it.

 

Yea man you are def missing some compression pulses based on how it sounds while cranking.

Your engine bay looks super clean man!!

 

also alot of headache can be avoided by paying attention to the symptoms. the last thing to do with a turbo rotary is keep mashing on the pedal when it is obviously hesitating.

 

thanks sir. the whole car is clean, honestly. its a very nice 10AE, just a paperweight as it sits right now.

the question isn't whether or not i need one (I do) but whether or not I want to do it. Weighing my options.

it is definitely toast. i brought my rotary compression tester in to confirm it.

stock injectors with the Rtek 1.5 on an S5 turbo with the wastegate and housings professionally ported as well as a lighter compressor wheel installed. Walbro fuel pump with stock injectors. Fuel is 93 octane. Racing beat turbo back exhaust. Water temp and oil pressure were rock solid. Hindsight being 20/20 as they say, should have taken the precautions of a wideband gauge, and didn't. The work done to the turbo combined with how it will boost higher without exhaust restrictions probably nailed the coffin. Originally I intended only to have the turbo rebuilt. The 'minor upgrades' which enticed me, well, lust is one of those seven deadly sins.

if there was detonation, i neither heard it nor felt it, and it is something I am acutely familiar with being in the business. the car pulled very strong, very smooth. being that I had just buttoned up things and started driving it again, i kept the spirited driving to a minimum. nothing seemed amiss until it bucked hard once and lost power for good. The only real symptom I ever noticed was the end result.

 

detonation is generally silent in these engines, especially with the more power you make the more rapid and soundless it becomes while the destructive nature ramps up. you can detonate an n/a and hear it loudly without causing much damage, it really depends on how high the combustion pressures are when it occurs.

 

i can tell you this much, not once did it hesitate or behave in a manner that would lead me to think there was a brewing problem. it was driving very well.

 

maybe i took this out of context:

 

sorry - allow me to clarify; after the car bucked hard under load, I let off the throttle, then reapplied partial throttle after a moment to keep the car at cruising velocity. when doing so, the car was bucking and misfiring, requiring more than usual effort to even maintain simple cruising speed, and it was not smooth. this lasted for a minute or so until i was able to realistically pull over to a safe spot where the engine subsequently would not idle without input and then died.

 

generally that would be due to running dangerously lean. the engine will give no hints whatsoever of a problem until it's too late.