Spark plugs... alky vs race gas

January 01, 2020, 09:57 PM

Mike Rietow

quote:
Originally posted by 358T:
62galaxie, If I didn't know what plug you ran before I would suggest a NGK -7 heat range plug for your lower compression milder combo.

Anyone who asks me I tell them to run the same plug as they did on gasoline (assuming it was close to the correct heat range plug) just make sure the gap is around 030 (assuming a CD ignition).

Going from a perfect tune up with the perfect plug heat range to a colder plug and then increasing the timing or taking away fuel just to get the plug to "look" the same or "right" does not mean it will make more power. In my opinion it will probably make less and be hard on parts.

Let's say you have the perfect amount of fuel and the perfect timing and the plug looks perfect. Now you change to a hotter plug or a colder plug. The different heat exhange rate means the plug will read differently and may make a person change the fuel or timing to get the plug to look right. But all that does is take the engine out of it's optimum operating parameters. Timing and fuel requirements are determined by the engines design parameters not the plugs heat range.

Scott

What if you do all that and go quicker, does that mean you made more cylinder pressure at the right degree after top? In that case did the parameter of the engine change or the parameter of your understanding of the parameters of the engine?

This is a rhetorical question btw.

January 06, 2020, 01:33 PM

358T

quote:
Originally posted by Mike Rietow:
quote:
Originally posted by 358T:
62galaxie, If I didn't know what plug you ran before I would suggest a NGK -7 heat range plug for your lower compression milder combo.

Anyone who asks me I tell them to run the same plug as they did on gasoline (assuming it was close to the correct heat range plug) just make sure the gap is around 030 (assuming a CD ignition).

Going from a perfect tune up with the perfect plug heat range to a colder plug and then increasing the timing or taking away fuel just to get the plug to "look" the same or "right" does not mean it will make more power. In my opinion it will probably make less and be hard on parts.

Let's say you have the perfect amount of fuel and the perfect timing and the plug looks perfect. Now you change to a hotter plug or a colder plug. The different heat exhange rate means the plug will read differently and may make a person change the fuel or timing to get the plug to look right. But all that does is take the engine out of it's optimum operating parameters. Timing and fuel requirements are determined by the engines design parameters not the plugs heat range.

Scott

What if you do all that and go quicker, does that mean you made more cylinder pressure at the right degree after top? In that case did the parameter of the engine change or the parameter of your understanding of the parameters of the engine?

This is a rhetorical question btw.

IMO, if a person changes fuel and timing and it makes more power then it wasn't perfect to begin with no matter the plugs heat range or if the plug read "right" before or after the change.

Scott

January 06, 2020, 03:21 PM

markemark

quote:
Originally posted by 358T:
Going from a perfect tune up with the perfect plug heat range to a colder plug and then increasing the timing or taking away fuel just to get the plug to "look" the same or "right" does not mean it will make more power. In my opinion it will probably make less and be hard on parts.

Let's say you have the perfect amount of fuel and the perfect timing and the plug looks perfect. Now you change to a hotter plug or a colder plug. The different heat exchange rate means the plug will read differently and may make a person change the fuel or timing to get the plug to look right. But all that does is take the engine out of it's optimum operating parameters. Timing and fuel requirements are determined by the engines design parameters not the plugs heat range.

Scott, I agree with all you wrote and practice it as well. I tune my mfi with pill and timing changes to achieve the best mph, and then fine tune for the most consistent et's . I rarely look at the plugs. These NGK-9 came out just short of 500 runs.

January 06, 2020, 07:22 PM

183N

And I thought I was cheap running plugs 100 runs

Someone said I should get NGK sponsorship because it’s easy to get. I said for what? Plugs cost $1.40 something on rock auto and we put a set per year in. If only they made blocks and heads

January 13, 2020, 11:40 PM

Mike Rietow

This is a 9, methanol. 64cc Brodix T1 14:1

I've run a good set of plugs I liked 2 seasons, 33 race season.

January 15, 2020, 10:07 AM

The Bozman

NGK9 on gas or Alky, DON'T MAKE IT HARDER THAN IT IS. Read the plug and it will tell you what it needs. end of story

January 16, 2020, 08:20 AM

Roger McGinnis

quote:
Originally posted by The Bozman:
NGK9 on gas or Alky, DON'T MAKE IT HARDER THAN IT IS. Read the plug and it will tell you what it needs. end of story

Maybe for a hard charger, but the OP definitely doens't need a -9. Just saying.

January 16, 2020, 04:30 PM

The Bozman

quote:
Originally posted by Roger McGinnis:
quote:
Originally posted by The Bozman:
NGK9 on gas or Alky, DON'T MAKE IT HARDER THAN IT IS. Read the plug and it will tell you what it needs. end of story

Maybe for a hard charger, but the OP definitely doens't need a -9. Just saying.

I have had an 11 to 1 bbc 460 that didn't matter if there was a -8 or a -9 or -10, the tune just changed, a little more or less fuel or timing. The motor will tell you what it wants.

January 21, 2020, 01:11 PM

HS professor

quote:
Maybe for a hard charger, but the OP definitely doens't need a -9. Just saying.

Silly question ........ What do mean by hard charger LOL

I'm building my first strictly alcohol car and I was planning on running NGK 9's

January 21, 2020, 01:21 PM

Mike Rietow

quote:
Originally posted by HS professor:
quote:
Maybe for a hard charger, but the OP definitely doens't need a -9. Just saying.

Silly question ........ What do mean by hard charger LOL

I'm building my first strictly alcohol car and I was planning on running NGK 9's

3200 lb 23 sbc dipping in the 5's N/A 10 x 28 tire. NGK 9

January 21, 2020, 03:54 PM

Bucky

I guess I always figured if you didn't overheat the plug nor foul it, you were in the ballpark heat rang wise. Moving around heat ranges sure can change how you read a plug.

I know what scott is saying as well. with my new combo I was lost enough that I was pulling plugs pretty regularly. IMO, once you are in the ballpark, smaller steps and watching the time slip and any other indicators you can will help eliminate the need to wear out the threads.

January 22, 2020, 08:53 AM

Roger McGinnis

quote:
Originally posted by HS professor:
quote:
Maybe for a hard charger, but the OP definitely doens't need a -9. Just saying.

Silly question ........ What do mean by hard charger LOL

I'm building my first strictly alcohol car and I was planning on running NGK 9's

The OP has a relatively mild engine that could be ran on pump gas on the street. I'd say you'd have to be ~1.75hp/ci before you'd ever need anything close to a -9 plug.

January 22, 2020, 12:00 PM

HS professor

quote:
The OP has a relatively mild engine that could be ran on pump gas on the street. I'd say you'd have to be ~1.75hp/ci before you'd ever need anything close to a -9 plug.

I'm right at 1.58hp/ci

I'm not a soft charger am I

January 22, 2020, 02:54 PM

CURTIS REED

quote:
Originally posted by HS professor:
quote:
The OP has a relatively mild engine that could be ran on pump gas on the street. I'd say you'd have to be ~1.75hp/ci before you'd ever need anything close to a -9 plug.

I'm right at 1.58hp/ci

I'm not a soft charger am I

Medium charger.

January 22, 2020, 04:41 PM

Alaskaracer

If you run E3, I guarantee you'll gain at least 100 hp and not less than a full tenth and several mph.......just ask them...

couldn't help it.....sorry........

January 22, 2020, 04:50 PM

HS professor

quote:
Medium charger.

Made my day !!!

January 22, 2020, 07:32 PM

Roger McGinnis

quote:
Originally posted by HS professor:

I'm right at 1.58hp/ci

I'm not a soft charger am I

Not if your 1.58 x 632; But maybe so if you're 1.58 x 350

January 23, 2020, 05:27 AM

Curly1

quote:
Originally posted by Coloradoracer:
If you run E3, I guarantee you'll gain at least 100 hp and not less than a full tenth and several mph.......just ask them...

couldn't help it.....sorry........

Lol, Sure.

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