Motor blew up, check out my tune.
 

So I got finally got my car back together with an MS3x the other day, spent 2 days auto-tuning it. Car ran pretty good, it had a hiccup when I'd get into boost real quick sometimes, but only happened maybe 6 times over two days of driving hard. AFR's seemed to be solid, I was running ~15psi on a GT2554R, unknown whp.

Then, I was on it hard through the twisties with a friend for ~20 sec of WOT, looked behind me, huge cloud of blue and white smoke. The motor was already a ticking time bomb as the compression was low and it burned oil all the time, I knew it wouldn't like going from 10psi to 15psi... I guess I just thought it'd last more than 2 days.

I can't get the MegaLog Viewer to open up on my laptop, but I did datalog one session. Can anyone check it out and see if it contributed to blowing my ---- up in any way? I haven't had time to dig into the motor yet, but I'm guessing it dropped a ring and/or headgasket let go.

Also, if anyone has any tips on what I should do/change in MS before I put things back together, that'd be great. It's a learning experience for me, and next time I'm putting on knock sensor in... however you tie that into MS.

Uhhh

Maybe if your motor was already mostly dead the boost killed it?

Just maybe?

Btw burning oil makes your combustion mixture very detonatable.

Looking at the logs with my noob eyes i'd say u were running lean, in some places only a little, but some places what i think is alot.

180kpa - 4.5krpm - 12.8/1
130kpa - 3.4krpm - 14.5/1
183kpa - 6.0krpm - 13.1/1

Im keen to see what others say, its totally possible engine just let go for no reason but im sideing with running lean over time.

Cheers
Scott

Little turbo + 15psi = pretty good heat. So 13 to 1 AFRs at ~180kpa = boom. Detonation eminent.

I'm at ~11 to 1 at 185kpa.

Six did you have a look at the log and come to that conclusion or just read what i posted? The above wernt "sustained" as such but for periods of 0.5-2secs. Just wont to be sure what u posted was what you saw rather than just from reading what i said.

Cheers
Scott

I didn't see the logs (at work), but if he really did go for 2 seconds @ 180kpa @12.8-13.0 that's stupid lean and probably melted a piston or something

I really don't get why people run these cars so lean. Where is everyone getting their "tuning info"?
We preach 11.25-11.80 afr's all day long over here, with the more ballzy people running 12.0 (which is lean IMO even with decent pump gas). I just don't get it.

I dont see anything inherently wrong with the log other than what the others said, maybe a bit too lean in some situtations. But either you messed up the timing sync and you were like advanced 5-10° throughout or the raw power that the ms3x cpu unleashed was just too mighty for your crippled motor.


Tune for 11.8 at the leanest in boost, and maybe start with more ignition retard in boost and only add more under controlled tuning where you can verify it's not pushing the limits.

Thanks for the responses everyone, its much appreciated.

I'll fatten it up next time around, auto tuning with low AFR targets. What kinda timing do people run on here? I'm pretty sure it was fairly retarded, but I didn't keep an eye on it when in boost.

Also, any idea on the big hiccup as I would get into boost? Maybe around 3k or 4k RPMs. Right as I would get into big boost it would cut and fall flat on its face. I don't have an EBC, just a cheap MBC, is there an over boost control or something? It happened enough to worry me.

I have a motor with a bad crank sitting in my parts Miata that I'm gonna take out, swap cranks with this one, and try this all over again. I don't see a need to build a motor as I don't expect to push over 240whp. Thoughts on that?

is the cutout event on the logs? what's the overboost on your map set to? it's around 200kPa right?

The hiccup is most likely boost cut.

Are you sure your other motor is in good shape? I would never EVER swap something like a crank without making sure all bearings are inspected and most likely swapped, as well as rings and a fresh hone. Its just common sense, and super cheap to do "while you're in there".

Start out with 10* @ peak boost and go from there for timing.

I don't know if I got a log with it or not, can't remember if it happened during these two or not, but these two are all I have.

I'll see if I can check the settings on the map when I get home. What happens if it were over boosting in MS?

it would cut out (stop injecting fuel/spark).

What kinda price would that be? Your super cheap and mine could be very different lol. I've got a few options to ponder while I figure things out. I've got a daily so this is my project for the summer.

I'm hoping the hiccup was boost cut as well, and thanks for the starting point with the timing.

rings are around 60-100 for a quality set.
rod bearings are like 30-40 iirc.
obviously you'll need a "gasket set" since you'll have to pull the head off/etc. so that's another 60 or so.

You can just do it right and have a semi-fresh motor in there, or just replace the crank and very likely end up with mediocrity or failure. The choice is always yours.



PS: and for another 200 you can throw rods in there. and have a motor that will easily hold 300.

I might just do everything above. Then I should be limited to the transmission at ~250whp, correct? I have two 5-speeds... is the only fix swapping in a 6-speed?

yeah, but you still need to be careful with the pistons...but you should be able to throw a bunch of power at them...but have to be spot on with timing/fuel.

I'd probably run ~240whp reliably and then see if I could get it dyno tuned to its safe limit. That's far down the line and a bigger turbo would be needed.

What happens to the transmission at ~250whp and how long would it last above that? There have to be people pushing more power with the 5 speeds, or maybe just beefed them up a bit. 6 speeds seem rare and expensive from my brief knowledge. Its almost a moot point right now but...

there is no magic number. I keep saying this in every thread about both the motors and transmissions.

it depends strictly on:
1) condition of trans
2) torque curve
3) how you treat it (also see #1)

I've had mine at 300 for a year then the guy that bought my car blew the trans in a few weeks. I've seen people blow their trans at 200, and a couple dyno queens hit 400

depends, you could see 300rwhp and it can be fine. dont abuse it.

I couldn't open the logs from the computer I was on so was working from above afr examples. It can only take once detonating under load to crack rings/pistons/both.

How did you set your base timing when you added the MS?

and you tuned the timing latency too right?

Boost can spike faster than an EMS can log it.

This can make figuring out your boost cut lurch kinda challenging sometimes.

I followed your instructions.

I did everything here:
Megasquirt-3 MS3 Checking ignition timing

I was actually seeing like 12 or 13 degrees at idle if I recall correctly.

but how did you line up your pulley marks when the timing was locked at 10°?

My buddy held the timing light and I increased the trigger angle. He told me when the outer and center pulley marks matched up.

so it looked like this:

https://www.miataturbo.net/attachmen...1&d=1342033488


???



and the timing latency, that's when the timing was still locked and you reved the motor up to make sure the timing didnt advance/retard.

He lined them up and I took his word for it. I know my plate was real dirty where it says 10, so its possible that the first mark lined up on the left and the second item lined up with the 10 in the middle. I'll find out, its very likely that could've contributed to the motor letting go if that's the case lol.

And yes, we revved the motor up and there wasn't any movement to like 5k but we did take a break or two in the middle of stuff because we were having problems with the software, so maybe settings were messed up.

Is there no way to read the timing from those data logs? How do you hook up a knock sensor to the MS3x for when I do this again?

Well if the trigger angle is off from what is acutal, the ms could say 40° and youre really at 10°.

go you still idle the car? at least do idle it, and point your light at it, you should se the yellow dot around the 15° mark...

at least we then can rule out if the timing was off as the reason.

I'm confused by your first sentence.

I can go idle the car on Friday afternoon and see where the timing is at.

ms doesn't magically KNOW what the actual timing your motor is running. therefore you calibrate it with the timing light. therefore if you mess up and do it wrong, the engine timing and what ms thinks engine is running are totally off. therefore the log will be useless and MS might be saying you run 10* when in fact your motor is running 20*.

etc etc etc

The reason you change the trigger angle to sync the timing is because the MS only knows what you tell it to be correct.

if you tell it something false, it will display something false.



its kinda like if I tell my wife we have $40 in the bank, and she spends $40, then we get an email frm my bank that our account overdrafted because we only had $30 in the account and they've charged us a $30 overdraft fee.

where what I told my wife is syncing the CAS timing, my wife spending $40 is what the MS is outputting, the email from the bank telling us that we were off by $10, and the fee is the blown motor.

Isn't that what they call GIGO, professor?

and by wife he means husband

also you didn't explain the rod in the tailpipe

piss off.

:fawk:

Is timing latancy something needed on MS2? ive never seen any references to it.

its needed on all MS installs, firmwares, versions.

I am going to add another thing here: as good as autotune is, it is really meant for a course tune. You will have to manually check everything. Specially if you suddenly change the boost from 10 to 15PSI. Typically the RPM will change too quick for autotune to pickup correctly unless you are on the dyno and doing a steady state tune.

I've been running a "coarse tune" for 6 years now.

After talking to my friend, I'm pretty sure we lined up the green mark on the pulley to the 10* mark on the plate. Therefore, the timing was probably ~10 too advanced compared to what MS thought, correct?

Hence my motor taking a ----.

Hmm, oh well. I was waiting for her to die, know I think I know why. Next time the timing will be set correct and I will richen the tune up a bit by autotuning it with lower target AFRs.

That funny that you have run a coarse tune for 6 years since the autotune feature hasn't been around for 6 years!!!

I've never dyno tuned.

and yes, the feature was available, it just never really worked well in megatune but the feature was there and I did use it.

But I used to "autotune" by using Phils VE analyzer feature within MLV by using logs a lot.

The autotune he built into Tuner Studio is more or less that same thing, just live or "auto."


I am highly confident that Phil's Autotune feature will get your VE table 95% of the way there if done correctly. and using EGO will get you the next 5%. Even in boost, even going from gasp 10 to 15psi suddenly.

Yes, his megalog viewer did have a similar system. However it all depends on how that is used. I have been using megasquirts since 2003 and didn't used to dynotune either. However I am saying that as a general statement. If someone does not know that they need to set the base timing properly, they shouldn't really be using the autotune either. Autotune does need to be setup properly. I have seen way too many cars blow something up because they didn't set their wideband and EGO settings properly. it was a recommendation for the person, not everyone!

i love you, bro.

Back at you!

If you had a drumset I'd come over and could play Rush together.

unless you're running a crank sensor
:party:

it should still be tuned/checked.

it's not about sloop, it's about latency. Where things happen a hell of a lot faster when the motor is spooing at 7000rpm over 1000rpm, so the MS needs to adjust for the physical delay in the action/response.

can you run higher AFR's if you have a water/meth system?

Sloops ahoy!!


https://www.miataturbo.net/attachmen...ine=1342721959

If you don't know how to tune and don't know the basic principles then you shouldn't be running water/meth. I'm not being a snob. Tuning is for the most part, easy.

hmmm. maybe sloop isn't the correct word.

Pretty awesome boat actually. So many sails. One mast!!!!