Plug Gap
Thread Starter
Melting Slicks
Joined: Oct 2007
Posts: 2,310
Likes: 9
From: KB7TIF Ville NV
Plug Gap
Ya Baby, Got this car from a lease manager at a chevy dealership. Plugs are fresh and were at .032. I opened then up to .044. Instant performance upgrade
Has anybody side gapped a set of plugs? worked well on my 350 Gta Transam.
Im going t side gap these,-.010 they wear out quick but what the hell
Has anybody side gapped a set of plugs? worked well on my 350 Gta Transam.
Im going t side gap these,-.010 they wear out quick but what the hell
Last edited by illenema; Apr 21, 2009 at 08:36 PM.
Le Mans Master
Joined: Sep 2000
Posts: 6,303
Likes: 714
From: Bartlett IL
Ya Baby, Got this car from a lease manager at a chevy dealership. Plugs are fresh and were at .032. I opened then up to .044. Instant performance upgrade
Has anybody side gapped a set of plugs? worked well on my 350 Gta Transam.
Im going t side gap these,-.010 they wear out quick but what the hell
Has anybody side gapped a set of plugs? worked well on my 350 Gta Transam.
Im going t side gap these,-.010 they wear out quick but what the hell
1994 Admiral Blue ZZZZZR1
Joined: Sep 2007
Posts: 2,688
Likes: 127
From: Jarrettsville, md
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Thread Starter
Melting Slicks
Joined: Oct 2007
Posts: 2,310
Likes: 9
From: KB7TIF Ville NV
Le Mans Master
Joined: Oct 2004
Posts: 6,314
Likes: 508
From: South-central Missouri
Say what?
Hmmmm.... Please forgive my ignorance, Dom. I'm not totally familiar (to a schematic level) with our ignition modules, but are the coils not fired by cutting off the "exciter" current in the primary side of the coil? I'm pretty sure they are. My point is that an "open circuit" (read: very high impedance) at the moment the module triggers the coil - more or less isolates the DIC from the load the coil "sees".
The coil, however, sees added strain to the insulation surrounding the windings in the coil, to be sure; about 13% or so increase in voltage when increasing from gap from .44 to .50. Perhaps more important is the heat increase in the coils due to Power = I (squared) x R law which rises dramatically - toward 30% more
Bottom line: I see the coils taking a hit for the added gap - no question (to say nothing of the effect on timing!).
Well, enough of all that Ohm's law stuff.
You have dealt with this to some greater length than most, so believe me I'm not impugning your expertise in any way. Ya just caught me off guard with the "taxing the ignition module" comment. Under normal circumstances there wouldn't be a "hit" to the trigger circuit, but the LT5 is not "normal" when it comes to ignition either! (And, now ya got my curiosity aroused and I'm gonna hafta go study the DIC in some depth...All your fault!
)
P.
The coil, however, sees added strain to the insulation surrounding the windings in the coil, to be sure; about 13% or so increase in voltage when increasing from gap from .44 to .50. Perhaps more important is the heat increase in the coils due to Power = I (squared) x R law which rises dramatically - toward 30% more
Bottom line: I see the coils taking a hit for the added gap - no question (to say nothing of the effect on timing!).Well, enough of all that Ohm's law stuff.
You have dealt with this to some greater length than most, so believe me I'm not impugning your expertise in any way. Ya just caught me off guard with the "taxing the ignition module" comment. Under normal circumstances there wouldn't be a "hit" to the trigger circuit, but the LT5 is not "normal" when it comes to ignition either! (And, now ya got my curiosity aroused and I'm gonna hafta go study the DIC in some depth...All your fault!)P.
Le Mans Master
Joined: Jul 2005
Posts: 5,328
Likes: 405
Hmmmm.... Please forgive my ignorance, Dom. I'm not totally familiar (to a schematic level) with our ignition modules, but are the coils not fired by cutting off the "exciter" current in the primary side of the coil? I'm pretty sure they are. My point is that an "open circuit" (read: very high impedance) at the moment the module triggers the coil - more or less isolates the DIC from the load the coil "sees".
The coil, however, sees added strain to the insulation surrounding the windings in the coil, to be sure; about 13% or so increase in voltage when increasing from gap from .44 to .50. Perhaps more important is the heat increase in the coils due to Power = I (squared) x R law which rises dramatically - toward 30% more Bottom line: I see the coils taking a hit for the added gap - no question (to say nothing of the effect on timing!).
Well, enough of all that Ohm's law stuff. You have dealt with this to some greater length than most, so believe me I'm not impugning your expertise in any way. Ya just caught me off guard with the "taxing the ignition module" comment. Under normal circumstances there wouldn't be a "hit" to the trigger circuit, but the LT5 is not "normal" when it comes to ignition either! (And, now ya got my curiosity aroused and I'm gonna hafta go study the DIC in some depth...All your fault!)
P.
The coil, however, sees added strain to the insulation surrounding the windings in the coil, to be sure; about 13% or so increase in voltage when increasing from gap from .44 to .50. Perhaps more important is the heat increase in the coils due to Power = I (squared) x R law which rises dramatically - toward 30% more
Bottom line: I see the coils taking a hit for the added gap - no question (to say nothing of the effect on timing!).Well, enough of all that Ohm's law stuff.
You have dealt with this to some greater length than most, so believe me I'm not impugning your expertise in any way. Ya just caught me off guard with the "taxing the ignition module" comment. Under normal circumstances there wouldn't be a "hit" to the trigger circuit, but the LT5 is not "normal" when it comes to ignition either! (And, now ya got my curiosity aroused and I'm gonna hafta go study the DIC in some depth...All your fault!)P.
You're correct that it'll take more power to jump the gap but that power has to come from somewhere. With coils, P(in)=P(out)-P(heat loss) where P(heat loss) is related to the efficiency of the coil. Any increase in power on the output side required to jump the gap will require an increase in power on the input side plus an additional amount for the extra heat loss from I^2R as you noted. The 1st Law of Thermodynamics says you can neither create nor destroy energy...or in laymans terms, you don't get something for nothing.
Le Mans Master
Joined: Sep 2000
Posts: 6,303
Likes: 714
From: Bartlett IL
Paul,
No umbrage taken. I will admit to passing along "possibly" an urban legend. I am no where as well versed on electronics as you or glass slipper and I skipped by Thermo at GMI. The DIS module does provide the trigger to the coil by grounding them in sequence, so its on the other side of the 12v feeding the coils. Although the ECM dictates the timing once motor reaches 400rpm, its the module that is sequencing and triggering the coils based on the crank sensor signal. To me that sounds somewhat analogous to what the points and distributor cap/rotor do (did).
As glass slipper posted, for more power out you need more power in and the LS coils pack a significantly hotter spark than ours. I'm wondering if that's part of the reason GM eliminated the module by distributing its function between the PCM and the coils themselves.
Have a look and let me know what you find.
No umbrage taken. I will admit to passing along "possibly" an urban legend. I am no where as well versed on electronics as you or glass slipper and I skipped by Thermo at GMI. The DIS module does provide the trigger to the coil by grounding them in sequence, so its on the other side of the 12v feeding the coils. Although the ECM dictates the timing once motor reaches 400rpm, its the module that is sequencing and triggering the coils based on the crank sensor signal. To me that sounds somewhat analogous to what the points and distributor cap/rotor do (did).
As glass slipper posted, for more power out you need more power in and the LS coils pack a significantly hotter spark than ours. I'm wondering if that's part of the reason GM eliminated the module by distributing its function between the PCM and the coils themselves.
Have a look and let me know what you find.
Last edited by Dominic Sorresso; Apr 22, 2009 at 10:32 AM.
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