Aaron92SE

iTrader: (128)

I figure I'd post this in the all motor forum since most of us in here aren't concerned too much about detonation problems with FI'd motors.

Who hear has thought about or has any information regarding using copper plugs that are one step hotter than stock?

This will be just for the track with a cool motor and ignition timing at a reasonable setting. 100 octane is also used because I run my base timing at the track at about 27 degrees instead of the stock 15* BTDC.

Before I install some hotter plugs, I want to see what you guys thought about going this route just to TRY to squeeze another single HP out of my motor ONLY on track day.

In theory, it should work. Thoughts?

Feed

Hotter?

If I understand you correctly, I would imagine you mean colder plugs...

If your jist is to move to a different heat range to avoid an overheated spark plug condition, I would imagine you mean colder plugs.

I'm not familiar with your modifications, but typical bolt on performance parts do not raise the combustion chamber temperatures out of the 500-850degC efficiency/safety range of your stock rated spark plugs. Typically, for every 75-100hp you add, a change of one step colder on the spark plug heat range is warranted.

I hope I understood your question correctly.

Best of luck

EDIT

So, would I imagine that your performance would benefit from moving heat ranges? I'm skeptically pessimistic...

Aaron92SE

iTrader: (128)

No I mean hotter. The hotter plug you have, the better chance you have of burning every ounce of fuel in the combustion chamber. But then that allows for hotter combustion chamber temps and you are closer to detonation.

Not many people run hotter plugs. But not many people are in my situation. I'm not even close to 75 HP over stock. My AFR is insanely rich. And I am far from detonating even though my base timing is advanced. I am only making about 180fwhp. I am looking for more ways to squeeze every ounce of power out of this motor and put it to the ground.

So I thought I might benefit slightly from going with a hotter plug to help squeeze out some more HP just for the track. I know some Corvette guys that aren't running a lot of power do this.

I'm definitely not interested in going with a colder plug b/c I would lose HP. It would be pointless since I'm not even close to preigniting.

Ninos_Maxima

iTrader: (5)

i think it should work... dont take my word for it though im not an expert. just using logic... colder plugs work better for F/I cars so then that should mean that hotter plugs work better for N/A cars. try it out on the dyno, its the only way youll know

Aaron92SE

iTrader: (128)

I was just hoping to find someone who has had any experience running a hotter the stock plug in their Maxima. I have found a couple copper plugs I can get, but am waiting on a response from NGK to verify a few things before I try to put them in my VE.

The only reason colder plugs were better for FI'd guy is not b/c they are FI'd. It's simply b/c their CC temps are hotter than normal b/c of the extra HP they are running. I am only about 40hp over stock and I know detonation is not out of hand. So I am sure I will be just fine if I am careful not to detonate.

I doubt anybody up here has run a hotter plug to try to get an extra single HP like I am doing. But it sounds like a good idea if you are in my situation.

Jime

iTrader: (10)

Hey Aaron I am thinking about doing the same thing this year. We may just have to try and see what it does. What I really want is the advanced timing function of the EU.

Aaron92SE

iTrader: (128)

Yeah. It won't hurt if you know you have the right plug, just one step colder and have the ability to know when you are detonating. Which I know you do!

I am still going to advance my timing more than usual and run 100 octane like I do at the track anyway just to be on the safe side. But along with this slower burning fuel, I figure hotter plugs could help ever so slightly.

I'll let you know if I blow my stuff up within the next couple weeks. As far as the gain in power, I won't be able to tell that since I have done SOOOOOO much stuff to my car since I ran 14.3. I am definitely on schedule to running anywhere from 13.5 to 13.8 on my next track visit. All motor of course.

Weimar Ben

iTrader: (5)

If you're advancing the timing, you might have to use colder plugs rather than hotter plugs. With stock timing on a NA engine, 1 step hotter plugs might not be enough to cause problems. I suspect the increase in power will be so small as to not be measureable.

If I were you, I'd try the hotter plugs with stock timing, then advance it little by little. If you have a piggyback, enriching it would help cool CC temps quite a bit.

You must have every mod known to man and done a big striptease to get a 3rd gen auto to run a 14.3. Good job.

NmexMAX

iTrader: (22)

He's just very effecient.. that's all.

SR20DEN

iTrader: (7)

I have tried three different heat settings (NGK PLFR(4,5 and 6)A-11) in mine but unfortunately I collected no data on the differences. However my gut feeling tells me the engine is happiest on the stock heat (5, for NA).

Jime

iTrader: (10)

My 3.5 ran its fastest N/A runs on 2 step colder Iridiums, with stock timing and pump gas. So I guess the only way is to experiment.

IceY2K1

iTrader: (3)

In theory the hotter the plug the more heat kept in the combustion chamber and the faster flame propagation occurs.

However, I'd assume the gains would depend on the particular vehicles knock threshold due to timing, combustion chamber design, cylinder head cooling, air temp entering the combustion chamber, fuel quality, etc.. Basically, you'd want to run the hottest plug possible without detonation, which would vary depending on those and other factors.

IMO, the extreme scenario to making the most power would be to run a J&S to pull EXACTLY the amount of timing necessary on the weakest link, ie cylinder that knocks first, while running the hottest plugs possible.

DandyMax

iTrader: (7)

That kind of surprised me a little when I heard it. Not what I would have thought. Could other factors have been at work?

It would be interesting to see what, if any, power gain would result from a hotter plug. My guess is it's negligible at the power levels we're talking about here but it's just a guess.

Aaron92SE

iTrader: (128)

I'm glad people are at least giving this idea a chance. I plan to experiment with this. I'm glad Matt (SR) has already messed with this idea. I know he's not scared to try new things in a Maxima!

I will try it with my timing at a reasonable level and see how far I can advance the timing on 93 pump gas. Then I will have a great idea how far I can push the timing at the track with a mixture of around 96 octane and cutout open.

My AFR is very rich for having a stock VE ECU. It's around 10.5:1 right now at WOT runs, but it's at around 14.1 - 14.5:1 during closed loop 02 sensor operation (cruising speeds and idling).

I know the stock VE is known to be rich from the factory, but maybe not THIS rich. Does anybody have any idea what could be wrong as to why I'm this rich? Broken injectors, broken fuel pressure regulator, etc? What gets me is that the mixture is fine during closed loop.

Anyway, since I'm so rich right now, I figure I might have room to play around with a hotter plug safely. I don't expect NGK to reply to email. The only copper plug I've found for my car is one made for a type of lawn and gardening motor. It's 4 heat range, but not offered at any automotive parts store. I'll have to order it online.

Aaron92SE

iTrader: (128)

I do have a ton of stuff done to my car. And I have a lot of weight removed. Since my mods list is WAY to big to post in my sig, I created one on my website. Check it out.

http://www.iwdwebdesign.com/maxima/mods.html

DandyMax

iTrader: (7)

Aaron it's no surprise that the mixture will be fine during closed loop because the ECU monitors the O2 sensors continuously and adjusts accordingly.

But WOT it does seem pretty rich.. have you checked your fuel pressure?

Machinist

The old fashion way to check for the correct heat range of a spark plug is to make a WOT 1/4 mile run.
turn the key off, pull over & pull the plugs,

you go by color
WHITE -- Too hot
BLACK or Dark GRAY -- too cold
GREY -- Thats IT!!!! you found the correct heat range

Aaron92SE

iTrader: (128)

Not yet. But I plan to shortly. The car runs fine, but is just rich. And of course, no CEL or codes.

Machinist, you are referring to looking at the ceramic part of the plug? Don't you have to pull the plug within minutes after the 1/4 mile run? What do you think about pulling a plug on a motor that's extremely hot with aluminum heads? I've heard too many nightmares about damaging the soft threads while pulling a plug on a hot alum head.

Machinist

Aaron
You can let the engine cool down, just don't drive or idle after the WOT run. you want to see the FIRING end of the plugs [you'll know when you look at it]
[turn off the key, pull over & coast to a stop]
Tom

Aaron92SE

iTrader: (128)

When I said ceramic, I didn't mean the butt end of the plug. I meant the part of the plug where the electrode meets the white surface. On that white surface, there will be discolorations or specs sometimes. That's how I've read plugs in the past. But I believe I drove it for a few minutes after my 1/4 mile run. I will make sure I turn the motor off as soon after I make the turn at the end of the track and coast down. Thanks for the help.

Weimar Ben

iTrader: (5)

Letting the engine run would actually cool down the motor faster since the water pump would be circulating coolant through the radiator. No need to turn the ignition off since 0% throttle position at any engine speed above 1500rpm or so turns off the fuel injectors. And your engine pumps air in and out which cools it as well. I would think that letting your engine bake after a 1/4 mile run is really bad.

Machinist

Yes, I knew what you meant, you're looking for the correct heat range for the 1/4 mile run, yes, then you need to see what the plugs look like after the WOT run, not after idling, not after low speed driving, not after normal driving.
Just look at the color of the end of the plug where the side electrode is attached & the center electrode [forget the white insulator]
I will follow this thread to see your results, good luck
Tom