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Indium Gray Metallic Money Pit Mk7.5R

scrllock

Autocross Champion
Location
MI
damn man. feels like if you're going built block, you'd want bigger turbo = more heat = more problems on track? or you'd need more cooling. feels like that gets very expensive very quickly
sort of. bigger turbo but with about the same boost, so you get more air with less heat. something like the DTR6054 is appealing since it was engineered around lowering EGT/EMAP. or a GTX2867 hybrid, though i'm not sure they sell those with a larger housing than an IS38.

Sucks, did you log that session at all?
logged everything over 70% pedal all weekend. so far nothing sticks out.

my shop guys know a guy endurance racing on an alibaba motor, trying to find out which supplier he used in case this block can't be re-bored.
 

ChrisMk77

Autocross Champion
Location
Sweden
Car(s)
2018 GTI Performance
Unfortunately these engines cant seem to take the prolonged track abuse without overheating the pistons with any type of hot tune, stock tune they pull all the timing advance and richen it up like crazy.

Maybe @Switchleg can patch in EGT sensor controlled WMI to the ECU.
 
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scrllock

Autocross Champion
Location
MI
Unfortunately these engines cant seem to take the prolonged track abuse without overheating the pistons with any type of hot tune, stock tune they pull all the timing advance and richen it up like crazy.

Maybe @Switchleg can patch in EGT sensor controlled WMI to the ECU.
definitely adding an oil pressure sensor with a safety toggle. EGT-scaled WMI would have to replace flex-fuel, and meth injection is more trouble than it's worth.
 

Pineapple

Autocross Champion
Location
Boston, MA
Car(s)
2017 Golf GTI S
definitely adding an oil pressure sensor with a safety toggle. EGT-scaled WMI would have to replace flex-fuel, and meth injection is more trouble than it's worth.
Can you explain why it's not worth the trouble? Safety related, tuning or?
 

scrllock

Autocross Champion
Location
MI
Can you explain why it's not worth the trouble? Safety related, tuning or?
To add methanol, you need to add either a pre-throttle or direct-port injection system. Pre-throttle, you add risk from all of the normal meth failure points (tank emptying, leaking lines/fittings, pump failure, clogged nozzles, as well as uneven cylinder distribution and damage to the throttle body.
Direct-port is much better in that you avoid the last two, at least. However, the only safety mechanism is monitoring a flow-sensor, we don't know if each meth injector is actually working without monitoring EGT per cylinder, which is essentially impossible with this cylinder head (if you look at serious V8s with nitrous, there will be an octopus of EGT probes running to a standalone). Also, the proper way to add direct-port on these cars is via an aftermarket intake manifold, which introduces further cost, fitment, drivability and tuning issues.

The ECU doesn't "know" if each OE injector is working either, it just knows how much it's commanding from each one and has labcoat models allowing it to infer when each cylinder is misfiring and then shut it down. With meth injection, we're at the mercy of the aftermarket safety patches, which are great, but not at the level of a proper standalone ECU. And due to the headifold, even if we are running an EGT probe, it's not going to have per-cylinder resolution.

The goal of adding monitoring for oil pressure, EGT, etc. is increased reliability. Methanol decreases the risk of detonation, but so does high-quality fuel, colder spark plugs, a good intercooler, and a safe tune. One oil pressure sensor is a single added leak point vs. many points of failure for a meth system. I'm comparing those since I think we have the option of using an extra ECU input pin for one 5v sensor on SP, and I think logging/correlating oil pressure is far more valuable.

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It'll be a while before I can get the motor out, but I've had several experienced folks tell me it's pretty unlikely the crankcase is reusable. I'm leaning towards building an Alibaba shortblock as simply/cheaply as possible. 9.3:1 Mahle pistons, forged rods, ACL bearings, ARP head studs. Re-use my head since the chinese heads seem to be where quality issues creep in. Keep the iabed oil pan, fluidampr. Send all the injectors out to get tested just in case that's somehow a contributing factor to the combustion temperature issue. Probably get a fresh OE R oil pump just in case.

I'm torn on a few things. One, whether it's worth even trying to make this car competitive given the motor failures. It's been expensive as fuck just keeping this thing on the road and doing casual HPDE, much less at a point where it's in a competitive environment.
Given the car isn't that streetable, it'd probably make sense to ditch the cat. Another potential failure point that could have caused this issue, and it makes sense to mitigate that while rebuilding.
I like having MPI, but it isn't strictly necessary on a stock turbo. Another set of injectors that can fail compared to dealing with the HPFP instead. I don't think I've seen any evidence that the fuel system contributed to any failures since ditching the aftermarket HPFP and continental DI, though.
Lastly, the elephant in the room, the tune. My logs are somewhat public, as is the tuner I've used and my engine failure. Not going to blame him, since there's no indication in the logs that the motor was hurt until the last pull or so. I should have been checking plugs regularly and doing a pre-season compression test and boroscope inspection. This may have given me more of a heads up that it was running a bit too hot (hence thinking about EGT sensors), but in my noob mind, moderate oil/coolant temps = motor isn't having heat issues. No one I've talked to has looked at my logs and said "oh, yeah, that's your problem." No fuel pressure or trim issues, timing and boost is what I'd call a stage 1 tune. There are dudes toasting their pistons with Unitronic tunes without apparent issues.

For now, I've made the initial e-acca purchase of all the new OE seals, gaskets, and bolts for the inevitable rebuild. Still shopping for everything else, always a bunch of extra costs you forget about. Not sure the rs3 filter is replaceable, so some sort of new LPFP. At least 8 quarts of break-in oil. A bunch more synthetic and oil filters. Fresh injector seals. Trans/flywheel bolts. Definitely new spark plugs. Turbo seems fine but it would be a great time for a new wastegate actuator. If I ditch the cat, it's way easier to swap a downpipe without a motor in the way. Also the best time to re-seal the weeping bevel box and DSG case. Maybe I will start a gofundme...
 

manu97

Autocross Champion
Location
Chicago
Car(s)
MK7 R
Might’ve missed it - might also just be ignorant. How do you know it was heat related? And not fueling or something else?
 

19birel

Autocross Champion
Location
Pittsburgh
Car(s)
MK7.5 - MK4 - B8.5
My heart actually sank when I saw the scoring in the cylinder, really sorry man. Admittedly this is making me a little scared to get mine back on track with the bigger turbo.

Do we know what an acceptable range for EGTs should be for these cars on track?
 

scrllock

Autocross Champion
Location
MI
Might’ve missed it - might also just be ignorant. How do you know it was heat related? And not fueling or something else?
oops-- didn't post most of the other pictures.
piston skirts scraping the wall, heat markings on spark plugs, oxidation on on the exhaust side of the crown. all of that points to too much heat in the combustion chamber->ringland failure. one theory proposed is that my intake cam timing was too aggressive and allowing for more valve overlap may have evacuated the heat out efficiently enough to avoid this. ignition timing was kept fairly conservative.

I'm logging nearly every time I'm on the gas, so I have tons of data with no indication of a fueling issue. erring on the side of rich vs. power, no fuel pressure drops. if anything it was richening up as it died.

of course, all sorts of other issues can contribute to ringland failure. LSPI (rare), bad gas (unlikely with shell 93 and minimal KR), poor oil (freshly changed castrol 5w40 euro, nothing special on a stock engine), etc. absent a mechanical smoking gun like a clogged exhaust, the obvious culprit is valve timing.


My heart actually sank when I saw the scoring in the cylinder, really sorry man. Admittedly this is making me a little scared to get mine back on track with the bigger turbo.

Do we know what an acceptable range for EGTs should be for these cars on track?
No, but I plan on talking to at least a couple guys who regularly tune with them. If anything the DTR6054 should be better in this regard, they use a larger a/r housing to compensate for the increased backpressure of stock downpipes.
 

scrllock

Autocross Champion
Location
MI
Couple questions about your steering wheel — brand/model? 330 or 350? And any airbag lights?
It's a KMP 330mm, basically an un-labeled OMP targa 330, which is what they use in the factory racecars.

No lights or codes. Used resistor plugs for the side airbags and transferred the stock passenger airbag module over and re-did the ground. Installed new wiring harnesses on both seats, plus the seat heater/occupancy sensor on the passenger side. Harnesses included new position sensors. And the zestek adapter works as an airbag simulator. Also have the 2door GTI seatbelt receptacles, fit better. But the seatbelt light is coded off.
 

ChristopherNeil

Autocross Champion
Location
San Diego
Car(s)
MK7 GTI
It's a KMP 330mm, basically an un-labeled OMP targa 330, which is what they use in the factory racecars.

No lights or codes. Used resistor plugs for the side airbags and transferred the stock passenger airbag module over and re-did the ground. Installed new wiring harnesses on both seats, plus the seat heater/occupancy sensor on the passenger side. Harnesses included new position sensors. And the zestek adapter works as an airbag simulator. Also have the 2door GTI seatbelt receptacles, fit better. But the seatbelt light is coded off.
Thanks for the quick reply. I had a Personal Neo Grinta 350 like a decade ago, but the offset bolt pattern rules it out... I'm just trying to decide which size to go with for when I pull the trigger. Maybe I haven't searched gated enough, but leather/red stitch/red strip would be awesome, but not a deal breaker.
 

scrllock

Autocross Champion
Location
MI
Slowly stacking parts. Rods should be here this week.

I'd say 90% odds I have to get a shortblock bored out, so I'm looking at 83mm pistons. Talked to Arnold Lee a bit, he steers me towards Mahle.
I see Eurocode has their pistons at $800, a bit cheaper than IE. Have them in my cart, I decide to call them on Friday and make sure they're in stock.
They call me back yesterday, say they're not in stock, 8-10 week ETA. I think on it, go to check out today, and they fucking raised the price to $1200.
I ask them WTF, "oh, since they're not in stock it's now a special order which is extra."
I've never heard of anyone else doing this--50% markup seems like fuck-off pricing, since IE is $200 less and they ship this week. Oh well, adding another vendor to the 'do not buy from' list.
 

scrllock

Autocross Champion
Location
MI
1724274386119.jpeg


Pulled a bit more out since I took this, hopefully have it on a stand tomorrow night. Obviously coming out the front, then we'll pull the trans off after.



1724274875914.jpeg



Allegedly about 22k on these valves, seems like MPI works better than not.


I have just about everything parts-wise, including a fresh oil pump, piston squirters, all the bolts. Timing kit, pilot bearing, the works.
Still need main bearings (crank-specific), valve springs (probably supertech) and I may replace some of these hoses and piping while it's easy.
Fresh plugs and injectors would be smart, still have to get the old stuff tested.

Found a machine shop to go through and see if this block can be salvaged at 83mm, otherwise it's back to hunting. Honestly will be impressed if it's rebuilt before the end of the year at this rate.
 
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