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Spark plugs

I run a tight .30 after the alky was installed.

Changed my plugs yesterday. #3,#6 were a lighter color than the rest. Plugs had maybe 1500 miles. I measured the gap for the hell of it and they were .38 I never had any spark blowout though.

Joe
 
I read somewhere on the TB boards that you close the plug gap .50 per pound of boost raised. So, if factory gap close to was .34 at 16.5# boost... If you run 20# boost, you would gap the plugs about .32 , 25# boost would be about .30

Just something I read. True, dunno...


Joe
 
tta229 is right under presser the spark is being blowen away from electrode tip in a arch low presser small arch high presser large arch spark gap to wide coil votage can not over come arch old school 70's 20,000 volt coil 80,s came hei and 40,000 voilt coils and gap went from 26/35 to 45/ as far as 80 plug gap add boost / presser wider gaps lose spark .you want to shorten the arch . keep the spark hot to get complete burn in cyl .
 
Okay,okay, so I've had some time to think about this and read that Super Chevy Article(which doesn't explain much, but again just makes the statment)and Cuda's explanation led me to a conclusion.

It's not that the spark is getting "blown out" as though the arc has been made and some big wind comes and snuffs it out like a candle...right?

It's more a function,or better yet, malfunction of the ignition system's ability to jump the gap in high horsepower applications.read: excessive cylinder pressure....yes??

So as super chevy says, 2000 H.P. twin turboed engine's need coils with more "ass" than the stock parts can provide.

So the same must be true for TB engine's. A spark never initiates at all is what I'm being lead to believe, and I'm understanding this....right??

If I'm getting this right.....I would still hazard a *guess* that 99% of us don't ever suffer from this...unless the ignition system has a weak component, as I can't imagine too many of us are near even a 1000 H.P. which is where I imagine problems could arise and the stock junk won't light off the fire...

Yes???....No????

..
 
WS6 said:
Okay,okay, so I've had some time to think about this and read that Super Chevy Article(which doesn't explain much, but again just makes the statment)and Cuda's explanation led me to a conclusion.

It's not that the spark is getting "blown out" as though the arc has been made and some big wind comes and snuffs it out like a candle...right?

It's more a function,or better yet, malfunction of the ignition system's ability to jump the gap in high horsepower applications.read: excessive cylinder pressure....yes??

So as super chevy says, 2000 H.P. twin turboed engine's need coils with more "ass" than the stock parts can provide.

So the same must be true for TB engine's. A spark never initiates at all is what I'm being lead to believe, and I'm understanding this....right??

If I'm getting this right.....I would still hazard a *guess* that 99% of us don't ever suffer from this...unless the ignition system has a weak component, as I can't imagine too many of us are near even a 1000 H.P. which is where I imagine problems could arise and the stock junk won't light off the fire...

Yes???....No????

..
Click to expand...
Well the way i'm understanding this is the amount of H.P has nothing to do with it, rather it could be like standing on the beach trying to light a match with a storm moving in, make sense? Btw, 1500 ft.lbs of torque? one word, WOW... that is one bad-ass twin turbo :guns:
 
robert lee said:
Well the way i'm understanding this is the amount of H.P has nothing to do with it, rather it could be like standing on the beach trying to light a match with a storm moving in, make sense? Btw, 1500 ft.lbs of torque? one word, WOW... that is one bad-ass twin turbo :guns:
Click to expand...

HP isn't directly correlated, but it is indirectly related via cylinder pressure. All else equal, more horsepower equates to a highler cylinder pressure.

Cylinder pressure is mostly what matters in reliability of anything mechanical. You have peak cylinder pressure at peak torque.

This is getting off topic, but a stock turbo'ed car at 30 PSI running 12.5@110 will have less of a chance of blowing headgaskets than a 61 turbo'ed car at 20PSI running 11.0@125. Why? Cylinder pressure. Boost is just a measure of restriction and not a measure of CFM flowing through the air pump-or in the case, the motor.

Truth is, Rich is dead on. When guys think they have spark blowout, they probably are experiencing some other causation factor like weak valvesprings, weak spark, or predetonation. All of the above will make the car nose over.

I would love to talk to the racers in TSM or the like about this. They switch to distributor setups to have a hotter spark and less waste spark. But, how did they know they ever had a problem? Someone a lot smarter than me figured it out and I bet it was just a wild guess looking at a summit catalog while on the toilet.

I will eventually switch to the coil on plug ignition system and remove all doubt. The coil on plug setups are good over 1500HP without an issue.

Carry on.
 
Right, and you increase the spark by upgrading the ignition system NOT tightening the gap. All that does is make the arc shorter and will alleviate issues with a weak system.

I'd love to see a log from tta299 showing spark issues.
 
robert lee said:
Exactly, you can't light a match in a storm but you can light a flare, in other words increase the spark
Click to expand...

Interesting metaphor there....but Im thinking about it like Jason is describing. Trying to jump 40K volts across a gap inside a pressurized vessel,like an air compressor's tank.If the pressure is 3X what it normally is then what factors in to this blowing out? I can't imagine "wind" per say in that scenario.Just an increase in pressure....with fuel molecules,etc.

After all....we are talking about .007 difference between the 2 gap(s) used here.
I also think it's an error of semantics and that "blowing out the spark" really means "a spark(arcing) failed to occur"...yes?

So,ultimately, it's an ignition system used beyond it's limits and design.


...
 
Well said and that is the key to all this,( a system used beyond it's limit's and design ) now if the gov. could understand that...
 
run a .35 gap at 31 psi see what happens .... I have a data loger installed on the GN with no passes an the tta has a fast system not tuned .....


I tuned my car an only me with a chip to get the 10.97 .. the converter was the issue... video is posted sounds like a powerglide pts converter ... it was brand new out the box made 2 passes ... way to tight out the hole an way loose on topend .... imo the car had atleast a 10.60 in it stock long block ... the 10.97 was blowing a head gasket @ the 1k foot mark ... it just blew through the converter .... champion heads ported by someone else made more power than like 5 sets of same heads ported by big names so im lookin for low 10's or high 9's in the GN then try to break the unbreakable 9 sec sg1 block tta head record .... jack merkle built my TTA engine no stoker just .20 over

149113_175801645767972_175798499101620_663154_1912866_n.jpg
 
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