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Once the water temp reaches the thermostat opens it is considered warmed up. Middle of the water temp gauge...
It's a 3" turboback (downpipe from artech, catback from corksport). Thanks for the water temp tip. I'm actually going to do the resistor mod to make it a linear gauge in a little while.
Hi there. I want to share this with you guys. I just open my engine after a failure with a lot of smoke and some pings.
First think the car was parked about 4 month to fix a problem with a broken crank bolt (I refuse to open the engine to fix that). 1 month of that because mechanic set the timing backwards.
First day of use I go to work driving slowly with no problems.
Then when I started drive to my home I passed some car on highway 2 or 3 km after leave the office (I suppose car was not warm enough). I see blue smoke behind me.
I drove slow for 5 min y then I made a quick acceleration and I see A LOT of SMOKE behind. Then the smoke start to appear without acceleration y starting to come from many places of the engine (not only exhaust) at the point that I can't drive any more because the amount of smoke at the cockpit.
Checked oil level and it is ok. engine was more noisier than usual but run.
I take the worst decision. To drive home no matter what happen (about 8 miles).
I reach home smoking from many places with a lot of noice on the engine, lack of power, not revving more than 2.800 RPM.
So, only one day of use and died.
Here are the results:
this left the car on the parking. I was using 10w-60 liquimoly maybe some of the factors involved
now looking for pieces to replacement.
Last edited by macanha; 08-13-2015 at 04:00 AM.
Reason: missing pict.
I think that most of the damage happen after I move the car to my home, after the smoke and noise associated. Maybe the piston fail by stress by old detonations and with a moderate, last charge.
According the mechanic the missing parts in the bearings are for heavy load or detonation.
Other pistos have marks of detonation in some place, not severe detonation, but had some scars.
The miata had standar pistons and rods but aftermarket bearing because many years ago I ran one TD run without oil.
The block is ok, according the mechanic I need standard pistons. I just buy another used crank, just for safety. Rods don't have any visual damage but I will take them away anyway.
What is this cold slap people talk about with wisecos? Is this some sort of inside joke on this forum? I've been running them for a decade and a half with no cold start problems. The engine just starts up and runs normally with no weird sounds or behaviors.
Putting the pistons in the engine in the first place, they were room temperature and there wasn't noticeable room around the sides, certainly not enough for them to move back and forth audibly.
My feeling about det is that a lot of people are holding two inconsistent ideas in their heads at the same time:
-it is the mark of a skilled tuner to be able to extract the maximum power out of a motor (usually by leaning it out and adding timing)
-it is the mark of an unskilled tuner to blow up an engine
So people tune their engines for maximum power and it holds together fine on the street and the dyno where nothing is getting heat soaked and their inlet temps are nice and cool.
And then they go to the track and heat soak the radiator/intercooler/intake manifold/head/etc.
Naturally, ECUs pull fuel as the intake charge gets warmer, lest the car run rich. Which increases the load on the heat exchangers.
And unexpectedly the threshhold for detonation is reached with a "good" tune because everything is hotter, and their well tuned engine blows up.
And yeah, you can run high high levels of boost on the street for ages, even with beating on it "mercilessly." Track beatings are just that much more severe than street beatings- I've never boiled brake fluid driving on the street, for example. I'm honestly a bit nervous of taking my newly rebuilt car back to the track even though I have gone overboard on the cooling and I'm running what I consider to be a fairly conservative tune and not extravagant levels of boost.
Last edited by AlwaysBroken; 06-23-2017 at 02:23 PM.
Reason: det comments added
I honestly wonder what would happen if you took a turbo miata and heated the intercooler up to 200F to simulate heat soaking before a few full throttle dyno runs. Bad things, I'm guessing.
How many ecus would competently adjust timing/fuel to compensate for this scenario?
And even if the adjustment was perfect, how many could still run 20 psi on pump gas when the intercooler and radiator are both heat soaked? 10? 5?
To put it another way, how much boost can you run on 87 octane, even assuming you pull a ton of timing?
I honestly wonder what would happen if you took a turbo miata and heated the intercooler up to 200F to simulate heat soaking before a few full throttle dyno runs. Bad things, I'm guessing.
How many ecus would competently adjust timing/fuel to compensate for this scenario?
And even if the adjustment was perfect, how many could still run 20 psi on pump gas when the intercooler and radiator are both heat soaked? 10? 5?
To put it another way, how much boost can you run on 87 octane, even assuming you pull a ton of timing?
I honestly wonder what would happen if you took a turbo miata and heated the intercooler up to 200F to simulate heat soaking before a few full throttle dyno runs. Bad things, I'm guessing.
How many ecus would competently adjust timing/fuel to compensate for this scenario?
And even if the adjustment was perfect, how many could still run 20 psi on pump gas when the intercooler and radiator are both heat soaked? 10? 5?
To put it another way, how much boost can you run on 87 octane, even assuming you pull a ton of timing?
A properly tuned ECU will compensate for what you are asking and be safe to run in those environments. I know for a fact long before you were on here we had some very good discussions about dyno tuning for track reliability. One of the big things that Hustler stressed that he found completely lacking in the tuners he talked to was what happens when the car is actually heated up as it would be on a race track. When he would do his dyno tuning, he would hold a constant mid range RPM until his manifold was glowing. Then he would start doing pulls and tuning in boost. He knew that was how his car would be like out on track and that is when you needed to find a safe MBT.
What is this cold slap people talk about with wisecos? Is this some sort of inside joke on this forum? I've been running them for a decade and a half with no cold start problems. The engine just starts up and runs normally with no weird sounds or behaviors.
Putting the pistons in the engine in the first place, they were room temperature and there wasn't noticeable room around the sides, certainly not enough for them to move back and forth audibly.
My feeling about det is that a lot of people are holding two inconsistent ideas in their heads at the same time:
-it is the mark of a skilled tuner to be able to extract the maximum power out of a motor (usually by leaning it out and adding timing)
-it is the mark of an unskilled tuner to blow up an engine
So people tune their engines for maximum power and it holds together fine on the street and the dyno where nothing is getting heat soaked and their inlet temps are nice and cool.
And then they go to the track and heat soak the radiator/intercooler/intake manifold/head/etc.
Naturally, ECUs pull fuel as the intake charge gets warmer, lest the car run rich. Which increases the load on the heat exchangers.
And unexpectedly the threshhold for detonation is reached with a "good" tune because everything is hotter, and their well tuned engine blows up.
And yeah, you can run high high levels of boost on the street for ages, even with beating on it "mercilessly." Track beatings are just that much more severe than street beatings- I've never boiled brake fluid driving on the street, for example. I'm honestly a bit nervous of taking my newly rebuilt car back to the track even though I have gone overboard on the cooling and I'm running what I consider to be a fairly conservative tune and not extravagant levels of boost.
Originally Posted by concealer404
Mostly internet legend as far as my anecdotes go. JE, Wiseco, Supertech. All sound the same at startup.
Originally Posted by AlwaysBroken
I honestly wonder what would happen if you took a turbo miata and heated the intercooler up to 200F to simulate heat soaking before a few full throttle dyno runs. Bad things, I'm guessing.
How many ecus would competently adjust timing/fuel to compensate for this scenario?
And even if the adjustment was perfect, how many could still run 20 psi on pump gas when the intercooler and radiator are both heat soaked? 10? 5?
To put it another way, how much boost can you run on 87 octane, even assuming you pull a ton of timing?
Originally Posted by concealer404
Like my underwear, depends.
LOTS of silly talk here
Biggest driver of cold start slap are loose tolerances. These will make any alloy piston slap like a diesel. It's worse on cp/wiseco because of the different alloy used. the softer supertechs tend to be slightly more forgiving if you're loose like hustler. its not just internet legend
as far as tune/heat soak:
the intercooler isn't the only thing that gets heat soaked, so its not enough to just heat one up during a dyno session.
also y'all forgetting bad gasoline. not just low octane, but bad as in dirty/contaminated batch.
also y'all forgetting blow-by causes all sorts of issues, even with the best fuel there is.
and blow by also happens to be the worst/most persistent on track. also you can't replicate that on a dyno or even a street tune unless you're crazy enough to street tune on a racetrack
also the other 6 billion variables that can happen, like some of the people experiencing fuel starvation on hard left handers. happens just for a split second, but that split second can claim a motor if you're not lucky
I could go on, but the bottom line is: there isn't some 3 point list of things that separates the cars that hold up to track abuse vs the ones that don't. and then even the best cars eventually splode. its just how it goes
Biggest driver of cold start slap are loose tolerances. These will make any alloy piston slap like a diesel. It's worse on cp/wiseco because of the different alloy used. the softer supertechs tend to be slightly more forgiving if you're loose like hustler. its not just internet legend
A little more on this. Its not that the supertechs slap less because they are softer. Its because the alloy expands less when its hot, which allows you to run tighter tolerances. The recommended PtoW gap is larger on weisco/cp's because they expand more when they get hot.
also the other 6 billion variables that can happen, like some of the people experiencing fuel starvation on hard left handers. happens just for a split second, but that split second can claim a motor if you're not lucky
That's a really scary thing. Not something I would normally even think about.
One thing I noticed when I had a couple of these motors apart for re-building was that the 9:1 aftermarket piston manufacturers did not pay any attention to maintaining a minimal quench area. They just used a flattop slug with a shorter compression height. Compare these (JE/Supertech) to an OEM turbo miata piston, you will find that the OEM has a slight raised ridge which closes down the quench.
It's my understanding that a tight quench area will squeeze the combustion mixture to the center, and makes for a faster burn. Correspondingly, a mixture that is spread out to the edges will burn slower.
How this ties in to detonation is that the slower burn will make this engine require more ignition advance to make the same power.
These pistons aren't cheap. For the $500 that I'm paying, I wonder why the piston manufacturers don't take quench into account (like the OEM did) and bring the piston up say .035 - 0.40 tight to the head, then the put a small dish to compensate for compression? ...less timing advance might buy us a little more longevity.
These pistons aren't cheap. For the $500 that I'm paying, I wonder why the piston manufacturers don't take quench into account (like the OEM did) and bring the piston up say .035 - 0.40 tight to the head, then the put a small dish to compensate for compression? ...less timing advance might buy us a little more longevity.
Did you actually measure squish or just comment based on how the piston looks? Every 8.6 ST slug I measure comes out at .040" squish, give or take a couple of thousandths.
Can't speak to JEs, I've never touched a set. All the Supertechs I've ever measured (8.6, 9.5s, 11:1s for sure, maybe a set of 9:1s I forgot about somewhere) were all .040" +/- .002"
05-14-2014, 03:22 PM
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