sounds like flat springs or the apex seals are pinched in the rotor

 

compression of zero is typical if an apex seal is broken clean through or is so destroyed that it left the groove.

Re: the turbine wheel, you'll have to remove the turbine housing in order to properly survey it for FOD.

 

Take the manifold off and take a look in the exhaust ports. Quick way to look at the damage before opening the engine. See if theres any color difference between the two.

thewird

 

Here are some pics of the turbine wheel. I also drained the oil and didn't notice any significant metal particulate. The oil looked brand new.

 

^Apex seals could have flown out the wastegate before hitting. Mine did that. At this point, time to pull the engine apart! I like teardowns

 

crackd just open it get over with it

 

I had a simular problem with my ecu, loss of data and I thought that was causing the motor to misfire. Turns out I had the wrong plugs and wires. went with BR10eg instead of b10egv and replaced the high dollar wires with some cheap ones from Napa. All my ecu problems went away.

Stock 9s are the wrong plug for the HP your looking at making IMO. It is not the heat range but the gap of the stock plugs. Try the br10eg at 20thou gap. They are cheap from rockauto.com

From what I was told, timing is based on the VE of the motor. Motor making good VE do not need lots of timing to make power. Ofcouse the more timing one uses the more power but at what cost. Air, water egt, oil temps and type of fuel also play roles in how much timing one can use.

 

FWIW, I run 9's all the way around and make 516RWHP...no issues.

 

Sorry to hear about your engine. I have been following your project in the old school forum since day one and I have been waiting for a 1/4mile pass.

Those egt numbers are way too high, even for a N/A rotary which usually indicates a lean mixture or a way too rich mixture and or a timing that is way too retarded could cause it too. I would definetely run colder plugs as mentioned and
check your ECU and wiring and make sure that is ok.

 

I was having weird rpm readings/glitches above 6k with my 20b with LS1 coils. I thought I was having trigger pick up problems with my Haltech E11. I couldn't understand why as I have my wiring well away from the coils. Actually my trigger harness runs all by itself on the passenger side of the car. I didn't know what the glitch was. Anyways what would happen is as I start to go past 6k, the gauge tach (on Halwin) would spike to 10k. I'm like WTF? I'm thinking well I guess my coils aren't putting out enough spark. So I crank the Ms value from 5 to 6. Everyone keeps saying run 5ms or 6ms with the LS1's. Well it got worse. I dropped it down to 4ms and now the engine revs very nicely with no sputters of hiccups. Not sure why a lower value would make my engine run better?

 

Let's not give the "almighty HC" more credit than he gets here already... The in-chamber pressure testing is being done by Barry Bordes ( https://www.rx7club.com/single-turbo-rx-7s-23/rotary-peak-pressure-location-atdc-907136/ ) and has NOTHING to do with howard. Thank you.

 

Does this mean that hitting a "spark cut" rev limiter can have the same effect?

If there is a leading plug mis-fire, but the trailing plug still ignites, will this damage the engine?

Numerous mentions have been made to reducing the EGT. Options on the table are AI and richer mixtures, but I have a hard time believing that 11.3 (assuming the wideband is right) AFRs are too lean. Am I correct in saying that the only other way is to advance the timing?

 

judging by the colour of turbine wheel, looks too lean to me. It should be more brown.

 

Have you taken the engine apart yet?

It would nice to see what actually failed.

Sometimes we have two problems raising their ugly head. A crack on an apex seal and an overboost.

I am impressed that a third problem didn't arise... even at 27 psi you had enough fuel and didn't go leaner.

My EGTs run as hot as yours do and going richer (high 10's) helps some.

Increasing the burn rate would increase power and cool the EGTs. Ideally I try to hit the tip of the red arrow.

Barry

 

sorry to hear this bro...

 

all very good questions,, of which the answer is never clear or established,, as nearly 30 psi on the street without AI is rare territory

as for question one,, leading miss-fire but trailing not
i wouldnt think was all that hazardous,, though may have some impact on forcing EGT higher to a critical point
( later burn )

i think rather the hazard is in leaving that trailing timing late on a normal combustion cycle may actually achieve a higher peak pressure over the trailing plug
-forcing self ignition there before the trailing spark can occur

this is due to dynamics of the chamber
and the fact that its compressing still on a flame front coming across from the leading chamber
---making for a very rapid rise in peak pressure over the already hot trailing plug

thus bringing in the trailing timing as much as 5 degrees earlier will cut that rise short before it goes critical*




as for the spark cut question,,, a very good one,, and i think under most conditions a total spark cut is a good thing ( except for turbos and cats )
but at 27+ psi,, and with already critical exhaust temperatures,, and lots of EGR then you have a diesel,, or lots of potential to
i also think that compounding your issue is that one rotor continued to burn AOK,, and may have had some sort of sympathetic reaction by super-heating the exhaust reversing back into the misfiring chamber

a study showing what is happening with a cut only on one rotor,, and what happens with EGT with a cut across both is the only way to qualify the theory


i think the cut needs to come on much earlier,,long before EGT becomes self critical

if it comes on at those high boost,, maybe it should be matched with a fuel dump,, or an A1 one,, to radically drop EGR during the missing cycles


* my own trials with trailing timing using LPG fuel have already apply indicated that this is the case in some conditions
( for me,, high inlet air and manifold temps due to lack of vapourisation heat exchange in the LPG fuel )

 

That is entirely possible. I have seen other peoples widebands read up to 0.5 AFR richer then what mine reads but usually they match within 0.1. That is why I replace my sensor every ~10 cars or so and recalibrate it every time before putting it in a new car. I've forgotten a sensor once in someones car that was pretty much brand new and they drove around with it, I just told them to cut it at the end and leave it as a plug and ordered a new one just to be on the safe side. I use the innovate LM-2 for tuning due to its portability.

thewird

 

Never seen such a concise, complete, inept collection of opinions and half arsed theories in all my life

 

Did you ring Ari yet? I hope you are not going to follow the "advise" you are getting for free in this thread there is a reason they are on forums you know

You only need one decent cook to make a broth you know

 

Then propose and argue for your theory, Peter. It takes much more courage than alienating damn near everyone on the forum who's trying to offer help.

B

 

which peter is this?

 

Peter-peter.......the pumpkin eater?

Sorry. Couldn't help myself.

 

Damn Nick, i loose my phone for a month and everything goes to ****!! Haha sorry to hear it bit the big one. When you get a chance call me and i will give you the high overlap, too little timing speech.

 

Well, I finally pulled the manifold off and looked in the exhaust ports. Everything looks good in rotor #1, except it is the one that has been leaking some coolant. Not sure what's up with that. Rotor #2 has two stuck apex seals, one which caused a small chip in the rotor. Can't see any cracks in the apex seals. It also seems rotor #2 was the one with the oil sneaking past the seals and causing the smoke.

Sean at A-spec took a look at the turbo and said everything looks good.

 

Can you see any evidence that the rotor has hit the housing? Are the seals stuck or did the springs flatten really bad?