richyvrlimited

iTrader: (1)

Just to note, OP is in the UK. It's not TDR that tuned it.

hornetball

iTrader: (4)

We know, just having fun with "mapper" vs. "tuner," "aluminum" vs. "aluminium," etc.

concealer404

iTrader: (3)

And "tuner" vs. "TDR."

A similar comparison would be "Barista" vs. "Starbucks."

Twodoor

iTrader: (2)

So, launch control is a no no on the Miata? Glad somebody else lost an engine before I tried it! Sort of a normal thing to use in the Mitsubishi world, so sort of surprised that it is not good on the Miata.

So much to learn!

Keith

18psi

iTrader: (76)

Its a no-no for OP and other n00bs that have no idea what they're doing on a super questionable tune and everything else.

Tons and tons of other people use it without too many failures like this.

The risks are obvious, and not any more dangerous on a BP than any other car.

richyvrlimited

iTrader: (1)

I have launch on my car. Must have used it total 3 times. After that the fun wore off. maybe it's a drift0r thing.

160rwhp from 13psi. I can manage that on my own, no need to pay anyone...

Braineack

iTrader: (62)

I used launch control every time I autoxed.

sixshooter

iTrader: (12)

It is common for cam timing to be off a tooth or two in our cars if done by inexperienced hands. Cams in an advanced position could help to account for the 181ft lbs below 5000 rpm and the reduced power above 5000, along with a stifling of flow by an inefficient exhaust tract.

The inadvertent increase in cam overlap coupled with the intentional misfire induced by the launch control may have allowed the reversion of the flame front from the exhaust manifold back into a cylinder that was in its intake stroke. The reason the gasses were still expanding in the exhaust manifold was because of incomplete combustion in the cylinders due to the launch control. So the gasses have already begun burning as the valves are closing and the compression stroke begins. The piston is trying to compress gasses that are already expanding and trying to push the piston back down. Cylinder pressures go through the roof as the crank is trying to push the piston up and the pressure is trying to push it down. The rod is suddenly stuck in the middle and resists momentarily before saying "**** this!" and he quickly makes a window to jump out of...

The moral of the story is that intentional misfires are always bad for an engine.
But only occasionally do they create spectacular and catastrophic failures.

pdexta

iTrader: (17)

Too bad we all convinced him to take the head off before checking the cam timing.

hornetball

iTrader: (4)

NVM

Sparetire

I'm not.

I am blaming the tuner for the launch control malfunction more or less.

I did a number of stutter box launches on my DSM without issue. Done properly IMHO it's fine. But with a crap tune that's puking fuel, it can be an issue. Sort of like boosting something with a crap tune. Not the turbo's fault.

Many stock cars have the same basic system in place anyway to prevent overrev due to keeping your foot in it too long. Works great and I see many guys bouncing off the limiter in 1st as a sort of traction control analog at the strip without issue. Doing the same at lower load and RPM is fine....unless its all messed up....

sixshooter

iTrader: (12)

Actually, that's a fuel cut and not a spark cut and it is completely safe for the engine. Overboost protection in MS1 uses a fuel cut, too, although with batch fire it's a bit harsh. You MS2 and newer guys proabably have something more sophisticated.

The problem with the launch control is that it is designed to make the fuel/air charge expand in the exhaust port and exhaust manifold to spin up the turbo. The engine is not designed for it. The exhaust isn't designed for it. The turbo isn't designed for it. It is a backyard engineering trick to try and make the system do something it has not been designed to do.

Horton

Right update

I got the spare engine in today.

I took the engine with the snapped rod apart. Turns out there were more holes than i thought. Guess I won't be using that sump then.



Now for the interesting bit. All the rods are bent! Now bear in mind this is a freshly rebuilt bottom end that has only done 3k ish since it's rebuild. It ran perfect when the car was n/a then 4 days with a turbo and this happens. I think it's safe to say something is wrong and this wasn't just a dodgy rod. All the bearings looks brand new (well they are only 3k old) the bottom end appears to be in perfect condition aside from the bent rods.



I've spoken to the mapper and he's checked the map over on his computer and he can't find anything wrong at all. He tried to explain how the launch control couldn't be firing on the up stroke but it went a bit over my head tbh. Apparently the car actually has a lower rev limit since the turbo was mapped so it should have actually been safer from a revs point of view. What the actual **** is going on? I'm scared to even the the ****** back on.

I don't want to name the mapper as I still think there's a chance this isn't the mapping but I am struggling to see what else it could be now tbh. I have asked him to check this thread to try to figure out what's going on.

Did the launch control bend the rods or were they bending as soon as I picked it up from mapping and the launch control just finished is off?

hornetball

iTrader: (4)

Bent ALL the rods at 181 RWTQ. Gosh, I wonder what it could be?

Your mapper owes you a motor.

Learn to tune yourself.

18psi

iTrader: (76)

You are useless.

No one is gonna help you if you're this useless.

Good luck with blowing up more engines. Keep trusting the "mapper".

Ryan_G

iTrader: (8)

You need to go to the mapper and watch him pull the tune file from your MS and the email it to you. Then you can upload it to this site and we can take a look at it for a sanity check. If you don't do this then you don't actually want help and you're just in denial not wanting to accept the fact that you may have paid someone to blow up your motor.

Horton

Maybe I'm giving the benefit of the doubt a bit too much....?

Can anyone think of any way this couldn't be mapping related? I do appreciate the help everyone. I've asked for the map to be emailed and a different local mapper has said he will check it over for me.

Also I did a compression test just after I fitted the turbo (but before it was mapped) and it was even across all 4

18psi

iTrader: (76)

the only way it wouldn't be mapping related is if somehow your injectors stuck open and flooded the engine, or your boost controller got stuck closed, overboosting like crazy, or your timing belt skipped a few teeth, or your car unbolted itself and advanced timing like crazy, or something drastic happened.

everything else points to tune

Here's what you do: download map directly from your ecu. Without letting anyone touch anything, upload directly to here. We will figure it out.
Don't let any "mapper" touch anything. Just download/upload. Done.

Otherwise, you're wasting time.

Braineack

iTrader: (62)

no. post the tune and we can put this to rest.

Horton

Or better yet could someone please explain how this could happen with no signs of det?

I'll post the tune as soon as I can