Spark plug heat ranges and detonation
07-05-2004, 06:12 PM
#1
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Join Date: Dec 2002
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Spark plug heat ranges and detonation
Anyone have a link to an online chart showing different heat ranges for AC Delco, NGK, Champion plugs?
I am looking for a plug that is either 1 or 2 heat ranges cooler than stock. My personal experience in my motor shows that the Rapdifire 3's are quite a bit cooler than the R44LTS6 plugs that I'm running now, despite the fact that they're supposedly the same heat range. I need something to cross reference this.
The Rapidfires would foul up pretty bad (motor burning some oil) whereas the R44LTS6 plugs come out clean a whistle, almost too clean for my liking. I'm battling some detonation at high ambient temps so I'm thinking the plugs are too hot. This is in a ~500 hp stroker FYI and I've tried pulling timing like crazy. Pinging happens at low RPM (~2K rpm) in high gear, basically lugging it along.
TIA.
I am looking for a plug that is either 1 or 2 heat ranges cooler than stock. My personal experience in my motor shows that the Rapdifire 3's are quite a bit cooler than the R44LTS6 plugs that I'm running now, despite the fact that they're supposedly the same heat range. I need something to cross reference this.
The Rapidfires would foul up pretty bad (motor burning some oil) whereas the R44LTS6 plugs come out clean a whistle, almost too clean for my liking. I'm battling some detonation at high ambient temps so I'm thinking the plugs are too hot. This is in a ~500 hp stroker FYI and I've tried pulling timing like crazy. Pinging happens at low RPM (~2K rpm) in high gear, basically lugging it along.
TIA.
07-05-2004, 06:37 PM
#2
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Join Date: Dec 1999
Location: Petersham, MA
Posts: 1,697
I believe it was NGK TR6 that I was running in my last cars stroker with nitrous. They are one heat range colder than stock. I never had any detonation issues and I had more power than you.
How much timing are you pulling? How much gas are you giving the car while in high gear? What is the compression ratio?
How much timing are you pulling? How much gas are you giving the car while in high gear? What is the compression ratio?
07-06-2004, 12:11 AM
#3
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I tried pulling upto 10 degrees of timing with no success. I run 94 octane in the car as well. I am giving it around 25-50% throttle when it pings. Any more than that and the tranny downshifts. It's also definitely related to coolant and ambient temp. As soon as it gets around 80-90 degrees on the IAT and around 195 degrees on the coolant temp it starts pinging.
The compression ratio is around 10.7:1 or so my builder tells me. But who knows....
Camshaft is custom and not that big so that's not helping neither.
The compression ratio is around 10.7:1 or so my builder tells me. But who knows....
Camshaft is custom and not that big so that's not helping neither.
07-06-2004, 08:39 PM
#4
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Join Date: Dec 1999
Location: Petersham, MA
Posts: 1,697
Are you running an LT4 Knock Module? My stroker in my last car experienced a nasty case of false knock when we first put it in.
Run some 100+ octane fuel and see if the problem goes away. If it doesn't, its probably false.
Have you run your engine specs through a compression ratio calculator?
http://www.rosspistons.com/calculator.php
You mentioned this being a 500 hp motor, but mentioned you are running a small cam? You must have a killer set of heads...
Run some 100+ octane fuel and see if the problem goes away. If it doesn't, its probably false.
Have you run your engine specs through a compression ratio calculator?
http://www.rosspistons.com/calculator.php
You mentioned this being a 500 hp motor, but mentioned you are running a small cam? You must have a killer set of heads...
07-06-2004, 08:43 PM
#5
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Join Date: May 2003
Posts: 2,275
Why don't you do a compression test to see what exactly the compression ratio is. Also you neglected to mention in your sidebar where you are located. This could have some bearing on the way your running versus how you had it tuned.
07-07-2004, 03:27 PM
#7
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Josh:
I am running an LT4 knock module and I've tuned it myself. I'm pretty well versed in the tuning domain. I know it's real knock because I can hear it and the knock sensor is picking it up as well. I've never tried race gas on a hot day to see if it goes away.
I didn't bother getting the engine specs from my builder so I don't have the data for the compression calculator. Now that the heads are off I will measure everything and see what it comes out to.
Yeah the heads are fairly decent...they are worked Canfields.
n2ceptor:
Thanks for the link.
I am running an LT4 knock module and I've tuned it myself. I'm pretty well versed in the tuning domain. I know it's real knock because I can hear it and the knock sensor is picking it up as well. I've never tried race gas on a hot day to see if it goes away.
I didn't bother getting the engine specs from my builder so I don't have the data for the compression calculator. Now that the heads are off I will measure everything and see what it comes out to.
Yeah the heads are fairly decent...they are worked Canfields.
n2ceptor:
Thanks for the link.
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