Built motors and detonation
12-15-2009, 10:34 AM
#21
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yea I'm running the 2871 which should be fine. The highest I've seen my Iat's were 99* after a long highway pull in 85* weather. Keep in mind that my temp sensor is mounted before my WI nozzle.
As for E85, I can't say that I've seen ANY stations local to me that carry it.
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12-15-2009, 10:41 AM
#22
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Was the piston eaten on the exhaust side?
HOw did the exhaust valve corresponding to that point in the piston look?
What happened there is that detonation eroded/melted the piston top, like it ate it. Too much advance can cause that type of detonation. Some motors that detonate slightly will do that, though usually they'll eat the head gasket first, like BMW motors.
When dyno tuning and doing just one pull, the piston tops don't get so hot.
On a track at WOT, the piston tops get very hot and the motor doesn't want as much timing.
If you run timing as tuned on a signle dyno pull, it will be too advanced.
According to Rebello, the way to avoid that is to do 3 quick dyno pulls 3x in a row. That will get the internals good and hot, simulating a long WOT run. Ideally the 2nd pull is a bit stronger than the first, and the 3rd is no weaker than the 2nd, or something like that. I don't know how to keep the intercooler exit temps the same though...
HOw did the exhaust valve corresponding to that point in the piston look?
What happened there is that detonation eroded/melted the piston top, like it ate it. Too much advance can cause that type of detonation. Some motors that detonate slightly will do that, though usually they'll eat the head gasket first, like BMW motors.
When dyno tuning and doing just one pull, the piston tops don't get so hot.
On a track at WOT, the piston tops get very hot and the motor doesn't want as much timing.
If you run timing as tuned on a signle dyno pull, it will be too advanced.
According to Rebello, the way to avoid that is to do 3 quick dyno pulls 3x in a row. That will get the internals good and hot, simulating a long WOT run. Ideally the 2nd pull is a bit stronger than the first, and the 3rd is no weaker than the 2nd, or something like that. I don't know how to keep the intercooler exit temps the same though...
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12-15-2009, 10:42 AM
#23
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That's kind of too bad; I saw several E85 stations coming down 75 and then on the FL T'pke. I say kind of too bad, because E85 is very bad for the taxpayers overall. However, you can use it in FI engines to make crazy power.
You will never get an accurate indicator of intake temp with WI because liquid will pool around the sensor.
If you're worried about the motor, the safest thing to do is to not tune it to rely on WI as its primary means for det resistance.
You will never get an accurate indicator of intake temp with WI because liquid will pool around the sensor.
If you're worried about the motor, the safest thing to do is to not tune it to rely on WI as its primary means for det resistance.
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12-15-2009, 10:57 AM
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12-15-2009, 11:02 AM
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12-15-2009, 11:12 AM
#27
It's all in the tune. Most people that spend the money to have a motor built also spend the money to have someone that knows what they are doing create the tune. Anyone that's playing around themselves and adding timing on the street is asking for trouble. Also having a timing map that's locked or only allows for limited corrections is a recipe for a blown engine. That's the safety margin that you track guys really need start exploring. What most of us run for corrections on the street is too small for what you track guys need.
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12-15-2009, 01:17 PM
#28
yea I'm running the 2871 which should be fine. The highest I've seen my Iat's were 99* after a long highway pull in 85* weather. Keep in mind that my temp sensor is mounted before my WI nozzle.
As for E85, I can't say that I've seen ANY stations local to me that carry it.
As for E85, I can't say that I've seen ANY stations local to me that carry it.
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12-15-2009, 01:20 PM
#29
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I guess you could say I blew my built motor, I morely unlucky than anything.
JE pistons, 83mm 9.0:1 CR, no wrist pin wire on one side in #4 = piston slapping :(
some det happened on one of my tunes:
I took pdextra's and paul's spark tables and mixed them together, listening for det thru a long tube. By the time I turned my MBC to 15psi it started to knock hard. Turns out I had metal shavings from tapping the oil pan and there was dirt from assembly.
top of the pistons didn't look too bad, though the cyclinder walls in #1 and #4 had some vertical scoring.
The engine was great until it started to knock. Hell it was even fun before I installed the turbo. It was surprisingly fast N/A, lightened internals are nice for throttle response.
Morale of my story, if you buy a pre-assembled engine online without paperwork, disassemble it when you get and clean all the parts and make sure every part is there. Don't let your friends intall the oil pan 30 minutes before you have the drill and tap for the oil return
edit: after further investigation the rod end-caps were also put on backwards, causeing abnormal wear on the bearings, ******* the engine up even more.
JE pistons, 83mm 9.0:1 CR, no wrist pin wire on one side in #4 = piston slapping :(
some det happened on one of my tunes:
I took pdextra's and paul's spark tables and mixed them together, listening for det thru a long tube. By the time I turned my MBC to 15psi it started to knock hard. Turns out I had metal shavings from tapping the oil pan and there was dirt from assembly.
top of the pistons didn't look too bad, though the cyclinder walls in #1 and #4 had some vertical scoring.
The engine was great until it started to knock. Hell it was even fun before I installed the turbo. It was surprisingly fast N/A, lightened internals are nice for throttle response.
Morale of my story, if you buy a pre-assembled engine online without paperwork, disassemble it when you get and clean all the parts and make sure every part is there. Don't let your friends intall the oil pan 30 minutes before you have the drill and tap for the oil return
edit: after further investigation the rod end-caps were also put on backwards, causeing abnormal wear on the bearings, ******* the engine up even more.
Last edited by flier129; 01-17-2010 at 07:23 PM.
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12-15-2009, 01:37 PM
#31
It won't tell you if the pump is not actually coming on though, just that the relay clicked over, and also won't tell you if you're out of fluid, or don't have pressure in the line (like due to hose/connector failure).
I originally thought about a red LED, but decided that was alarmist and went with a calming color since it being on is a good thing. RadiosHack didn't have blue that day so I got a green that matches gauges. I would do a level switch in red though to get your attention.
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12-15-2009, 03:04 PM
#39
The one big thing that still worries me is that with a progressive system, there is still a window for error while using a flow sensor as a failsafe. A partially clogged nozzle most likely won't create a situation that will trigger the failsafe.
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