Motor carnage
#21
Safety Car
Thread Starter
As for AFR, I know it would have been safer at 11.2. I'm learning as I go with what works and doesn't (as many of us do), your input is appreciated. I have ran in the 11.7 range many times at the 1/2 mile events, usually at closer to 21-22
here are the rest of the pistons.
#23
Burning Brakes
#24
Safety Car
Thread Starter
With no smoking gun, like an injector, its hard to tell. It did get beyond hot in that cylinder
Less timing next time and a little richer on the AFR is a good place to start with on the next motor.
#25
Le Mans Master
how was the head gasket? looks like it blew and took the head out from the new exhaust path
#26
Safety Car
Thread Starter
#27
Drifting
Those are weisco pistons correct? Lots of guys talk about that super thin area on the sides as a hot spot to start melting things. I would almost blend that back a bit while balancing the setup if you use more in the future.
#28
Melting Slicks
It's hard to tell from the photos, but some of the pistons do look like there is some peppering or little detonation marks around the top edge on one side ?
What do the ring faces look like ?
Either way, the damage is pretty classic detonation. If all injectors are ok, where is methanol being injected ? Can you be sure all cylinders are seeing even amounts ?
What ecu is being used ? Maybe it's having an issue with either rev limiters, traction loss etc etc ? and allowing things to misbehave
And oil squirters always worth having for distance type events to help cool the pistons.
8's would be a safer choice, although on race fuel things should be cooler in there ?
I run mine in the high 11's under boost on pump+meth and havent had any issues since 2008 ( when I really blew one up big time lol ). Over 25psi I do drop it to around 11.3 or so though.
Cant comment on any race fuels though.
What do the ring faces look like ?
Either way, the damage is pretty classic detonation. If all injectors are ok, where is methanol being injected ? Can you be sure all cylinders are seeing even amounts ?
What ecu is being used ? Maybe it's having an issue with either rev limiters, traction loss etc etc ? and allowing things to misbehave
And oil squirters always worth having for distance type events to help cool the pistons.
8's would be a safer choice, although on race fuel things should be cooler in there ?
I run mine in the high 11's under boost on pump+meth and havent had any issues since 2008 ( when I really blew one up big time lol ). Over 25psi I do drop it to around 11.3 or so though.
Cant comment on any race fuels though.
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Mike04 (11-12-2017)
#29
Safety Car
Thread Starter
#30
Melting Slicks
A hot piston simply doesnt melt....melt the piston, nor the steel rings around it.
Detonation will blow it's way through though. The cause of detonation may be unclear, but the damage it left behind is very clear.
That is in no way a fault of the piston
Detonation will blow it's way through though. The cause of detonation may be unclear, but the damage it left behind is very clear.
That is in no way a fault of the piston
#31
Safety Car
Thread Starter
It's hard to tell from the photos, but some of the pistons do look like there is some peppering or little detonation marks around the top edge on one side ?
What do the ring faces look like ?
Either way, the damage is pretty classic detonation. If all injectors are ok, where is methanol being injected ? Can you be sure all cylinders are seeing even amounts ?
What ecu is being used ? Maybe it's having an issue with either rev limiters, traction loss etc etc ? and allowing things to misbehave
And oil squirters always worth having for distance type events to help cool the pistons.
8's would be a safer choice, although on race fuel things should be cooler in there ?
I run mine in the high 11's under boost on pump+meth and havent had any issues since 2008 ( when I really blew one up big time lol ). Over 25psi I do drop it to around 11.3 or so though.
Cant comment on any race fuels though.
What do the ring faces look like ?
Either way, the damage is pretty classic detonation. If all injectors are ok, where is methanol being injected ? Can you be sure all cylinders are seeing even amounts ?
What ecu is being used ? Maybe it's having an issue with either rev limiters, traction loss etc etc ? and allowing things to misbehave
And oil squirters always worth having for distance type events to help cool the pistons.
8's would be a safer choice, although on race fuel things should be cooler in there ?
I run mine in the high 11's under boost on pump+meth and havent had any issues since 2008 ( when I really blew one up big time lol ). Over 25psi I do drop it to around 11.3 or so though.
Cant comment on any race fuels though.
Meth is injected before the TB. I've thought about the possibility of not getting as much meth to the forward cylinders. I've read about it being forced more so to the back of the intake. I'm considering go with a direct port type setup on the new build.
P59 PCM (2004). I didn't bounce it off the rev limiter over the past few runs but traction required a lot of pedaling so it did rev fast.
I wanted to put the oil squirters in the original build but was talked out of it back then. They will be added this time around.
Thanks for your input on the AFR and plugs.
#32
Le Mans Master
I was enchanted with direct port meth but I believe flex fuel and e85 is both easier and better
you are right that you can have distribution problems which could be the root cause on the hot spots.
that is blow torch stuff, no piston would have done well under those circumstance.
we did some experimentation on a big blower car with egt and found the back cyl way rich and the fronts way lean on a 1200 hp car
egts were 300 deg apart and although the widebands and everything was "rich enough" the rear cyl were too rich and the fronts just "ok"
evening everything out to 50 deg or less variance brought out some hiding power.
02s only tell you part of the story of what's happening and are an "aggregate" of the cyl.
give each cyl what it wants and needs.
you are right that you can have distribution problems which could be the root cause on the hot spots.
that is blow torch stuff, no piston would have done well under those circumstance.
we did some experimentation on a big blower car with egt and found the back cyl way rich and the fronts way lean on a 1200 hp car
egts were 300 deg apart and although the widebands and everything was "rich enough" the rear cyl were too rich and the fronts just "ok"
evening everything out to 50 deg or less variance brought out some hiding power.
02s only tell you part of the story of what's happening and are an "aggregate" of the cyl.
give each cyl what it wants and needs.
#34
Burning Brakes
we did some experimentation on a big blower car with egt and found the back cyl way rich and the fronts way lean on a 1200 hp car
egts were 300 deg apart and although the widebands and everything was "rich enough" the rear cyl were too rich and the fronts just "ok"
evening everything out to 50 deg or less variance brought out some hiding power.
egts were 300 deg apart and although the widebands and everything was "rich enough" the rear cyl were too rich and the fronts just "ok"
evening everything out to 50 deg or less variance brought out some hiding power.
So true.