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Rebuilding motor, spun a bearing

Old 01-15-2018, 06:43 PM
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Originally Posted by Pintobeantoes View Post
also, could it just be that I was over the 250HP limit?
No.

Could this just be a simple HG blowout?
No.
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Originally Posted by codrus View Post
Basically I've come over to the camp of "If something is a reliability problem on the track, just ask Andrew and do what he says".
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Old 01-15-2018, 07:18 PM
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Here is the datalog I took the day before, just after updating the firmware, the idle was really high because the idle setting had reversed, but I got that corrected. I increased the boost limit further after this, before reviewing this datalog completely, so while this peaks at 194.3 kpa, it is very likely that when i had it set to a 200 kpa limit it was peaking above that. I thought I had recorded a datalog from that morning but I guess not.. :/

On another note, what makes a 250 HP BP? What is the max boost a stock motor could take given the "perfect" tune?
Attached Files
File Type: msl
2018-01-12_14_modified.msl (2.32 MB, 14 views)
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Old 01-15-2018, 07:34 PM
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Originally Posted by Pintobeantoes View Post
What is the max boost a stock motor could take given the "perfect" tune?
ALLOFIT
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Old 01-15-2018, 08:40 PM
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Originally Posted by Pintobeantoes View Post
Here is the datalog I took the day before, just after updating the firmware, the idle was really high because the idle setting had reversed, but I got that corrected. I increased the boost limit further after this, before reviewing this datalog completely, so while this peaks at 194.3 kpa, it is very likely that when i had it set to a 200 kpa limit it was peaking above that. I thought I had recorded a datalog from that morning but I guess not.. :/

On another note, what makes a 250 HP BP? What is the max boost a stock motor could take given the "perfect" tune?
Well, there you go, you were definitely overboosting. Not sure if you ran out of fuel or luck as you haven't posted any other details about your car.

Asking "what is the max boost" any motor can take is a bad question and nobody is going to bother answering that.
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Old 01-15-2018, 08:56 PM
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Originally Posted by Pintobeantoes View Post
... What is the max boost a stock motor could take given the "perfect" tune?
This is a big question that will vary HIGHLY depending on who you ask. It depends a lot on the setup itself. A small turbo making 250whp will be more likely to bend rods than a bigger turbo making 250whp, for several reasons. The definition of perfect tune is also debatable. Perfect as in, optimized for power? Optimized for 93 octane? Optimized to not break when you get a bad tank of gas? Optimized for track duty? My idea for a "perfect tune" for a stock motor is a tune that errors on the side of safety above all else. But that means it's not gonna make the power a more aggressive tune would make.

FWIW, I ran 17 PSI on my stock 99 motor for about a year before I killed it. Overboosted to 22 PSI a few times. I bent the rods with a 100 shot of nitrous before I ever turbo'd it, then boosted it with two bent rods. After a year of abuse the thing shook the front crank bolt out that holds the balancer on and destroyed the keyway in the crank killing it.
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Old 01-16-2018, 01:16 AM
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Originally Posted by Pintobeantoes View Post
any suggestions? I have no engine building experience but I do have a cherry picker. I was gonna pull out the engine and take it to a build shop in the SA area.
I didn't have any engine building experience before I built mine. That being said, 220whp doesn't require a build at all. Just swap in another 1.8 and put a turbo on it with 12 lbs of boost. With a decent tune that will easily hit your power goals and still be reliable. Countless people were hitting 220+ with boring builds on stock motors like 20 years ago.

From the description of your problem, I bet that you killed your engine with shitty tuning. You are running way too low a power level to kill a stock BP. Also, the fact that your engine died from highway pulls right after you raised the boost (especially since you raised it from really low to sorta low) tells me that you probably ran lean and damaged something because you tuned your car poorly. Or there's something else grossly wrong with your setup that isn't obvious from your posts.

You need to remedy your ignorance before you put any more money into this. Don't spend any money on this until you run compression/leakdown and then take the whole thing apart to figure out what went wrong.

Some other things you brought up:
  • Don't waste money on head work for any sort of modest power build. Good headwork is expensive and raising boost is cheap.
  • Don't get headwork done on a pre 99 head. They flow for **** and you're just polishing a turd.
  • Don't go for higher compression to make more power unless you're running ethanol. You get a much bigger margin of error for timing running 8.5 vs 9.5 compression and the power difference is modest at a given boost level. And since the lower compression motor can run more boost safely...
  • Honestly, every penny you sink into the above unnecessary power mods is money you aren't spending on reliability mods. Instead of getting a junk 2 intake, get a coolant reroute. And so on.
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Old 01-16-2018, 02:56 AM
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Just get an unopened BP4W with VICS intake and learn how to tune.
Unless decent BP4W are getting rare as unicorns and expensive that's a route that's much faster and fit for purpose (the lack of engine building knowledge is not your issue, so why start there?).
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Old 01-16-2018, 10:44 AM
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Thank you very much for the lengthy reply and suggestions! I do have a coolant reroute and have upgraded the cooling system quite effectively. No issues there.

tuning error. Everyone keeps pointing to that while only one person has really been specific.. boost spike. Could a spike up to 20 psi bring the car to 250 hp?

Cure my ignorance? Tune better? I had been running MS n/a for a few years as suggested here so i thought I was doing things correctly. I posted a log that nobody has commented on. Im not giving up but I dont wanna just waste money. I answered the questions about afr, is 11.8 too lean? I dont think so. I had just recalibrated my o2 sensor. Are the ign timing values i listed off? By how much?

of course theres a lot to learn from tearing it apart, but if it IS a tuning error mainly at fault here, i think it should be evident from either the tune or the log

so i might just drop in a 99/00 long block and call it good for my power level goals? I wouldnt try porting the na head.. haha. Im not as new to miatas as you might think. But it does take some humility to open up to yall here on MT

i might add that on the stock wastegate pressure ~8psi the car ran great, idled great, hit afrs smoothly, and didnt grenade lol. The ebc, a boost gauge, and a firmware update were all that I changed.
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Old 01-16-2018, 10:55 AM
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Even if you went over 250 hp that is not what killed your engine.
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Old 01-16-2018, 11:03 AM
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Originally Posted by Pintobeantoes View Post
The ebc, a boost gauge, and a firmware update were all that I changed.
You say this like its trivial. FW updates can wreak havoc if the tune isn't combed through after the update. The EBC was already described to you. If I remember, ill look at your tune and logs when I get home, but there are other who are much better at that, than I am.
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Old 01-16-2018, 11:04 AM
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Originally Posted by matrussell122 View Post
Even if you went over 250 hp that is not what killed your engine.
gotcha. Probably ran lean in the overboost cells, as I hadnt planned on hitting those cells. And because of negligence i hit those boost cells a lot. Was having a blast with the new found power until boom
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Old 01-16-2018, 11:32 AM
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You can break your rings at 180 horsepower with detonation by running too lean or too much timing or too much oil in your combustion chamber. Stop focusing on stupid **** like 250 horsepower. It's just a number and lots of people have destroyed their engines at far less than that. 250 horsepower is around the limit if everything is perfect. Nothing about what you've described would cause me to use the word perfect.

You've made lots of assertions about things you don't know. You have not yet taken apart the bottom end to see if you have a spun bearing. You may have a bent rod or broken piston(s) or water in your oil from a blown head gasket wiped out all the bearings and galled the cam bearing surfaces.

All we do know is that you had a **** tune on a motor that was already hurt. The result is no surprise. Take some pictures when you get it apart and then we'll know what happened but I'm pretty confident with the "why" already.
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Old 01-16-2018, 12:40 PM
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At your boost level, it's a crap tune. My original build like 15 years ago inherited a lot of parts from some guy who blew up his motor at 6psi. I drove on the stock motor with those same parts and a safe tune at 15 psi on a larger turbo for a year with no problems before I built the motor.

One thing I don't get is why you would not program in your high boost rows to be pig rich with retarded timing, especially if you never plan to hit them. Leaving them lean seems like a blatantly retarded thing to do.

What size injectors are you running? Original fuel pump? What year?
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Old 01-16-2018, 06:51 PM
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Originally Posted by Savington View Post
A well-tuned turbo BP will run until it burns so much oil it no longer needs gas
Or runs out of oil.

(ask me how i know)
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Old 01-17-2018, 12:06 AM
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Originally Posted by aidandj View Post
Or runs out of oil.

(ask me how i know)
How do you know?
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Old 01-17-2018, 12:20 AM
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I ran a motor out of oil
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Old 01-22-2018, 08:08 PM
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My .02
Listen to the others, they have some (lots) good advice.
Based on the bad noises you described on the first page and the (smarter than me) others conjecture, my WAG as to what happened is the extra boost put you into an untuned area of the map, possibly causing some light detonation, then a boost spike for whatever reason plus the detonation = piston failure, probably around the ring lands by the exhaust valves, as that is the hottest and therefore becomes the weakest area of the piston. Take it apart if you want and see the damages.
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