Colder plug recommendation

[Boxer12]

With the upgrades to my 09 ACR, Dan suggested I run a one step colder plug. I checked with Champion Tech Service and they don't make one. Any recommendations?

 

[Allan]

I use the NGK iridium plugs listed for the car by application. They are supposed to have a wider effective heat range than a standard plug, and they will last longer. They are not cheap, and are not considered a 'gimmick' plug like 'split fire, or E3, or Platinum+4, or Rapid Fire, or any of that crap'. They are at a price point for their quality. Unless someone has a better suggestion, I highly recommend these.

 

[Steve M]

Gen III and Gen IV engines do not use the same spark plugs...a set of factory plugs is ~$75 from VPA for the Gen IV...the Gen III OEM plugs are substantially less.

 

[Boxer12]

The OEM plug for Gen IV is Champion RE10PMC5 Single Platinum Spark Plug. According to sparkplugs.com, the NGK replacement is NGK 3381 LZTR5AGP Single Platinum Spark Plug, and the Bosch replacement is Bosch 6732 HR8SPP300V Single Platinum Spark Plug. I found a heat range conversion chart on another website. http://www.championsparkplugs.com/learning-center/article/225/heat-range-conversion-chart.

I guess the thing to do is just search for something with a lower heat range than the OEM in one of these other brands. Using the chart, that would be NGK LZTR7AGP? Or, Bosch HR5SPP300V? When I google those numbers, I don't find anything. What am I doing wrong?

I don't want to be the guinea pig, so anyone here who is running +75 HP mods to a Gen IV should let me know what is working! I know I'm not the only guy with ported heads, intake etc. Thanks.

 

[Garron]

Hey Boxer,

The "number" (RE10PMC5) in the middle of the spark plug part number is the heat range of the plug, the lower the number the colder the plug.

From factory RE10PMC5 is a cold plug, By comparison a Gen 3 vehicle ran a heat range of 12. I would continue to use the factory plug

 

[ViperGeorge]

I also have ported heads and ported intake from Dan. Have ACR-X headers and high flow cats. I use the standard plug. Knock on wood, never had any problems. Now on my old Gen 3 with a Paxton I did go with cooler NGKs from Dan but that was supercharged.

 

[Boxer12]

Per one of my sources, some Cup cars have switched over to Champion 7437 RE7PYP6 Double Platinum Spark Plug per Winkles' advice. Coincidentally (or not), it is a one step colder plug than the OEM. I will get a set and take it to the dyno to test.

I want to go with Dan's recommendation of a colder plug to see if I get better performance, since he has done a lot of testing with these heads/intake/race exhaust setup. That the plug was recommended for the Gen IV motor by Winkles makes it a safe bet.

For the benefit of guys using other manufacturer's plugs, the Champion guy mentioned that if I go with a 'race plug' or some other manufacturer, make sure any plug I choose has same reach and he emphasized a tapered seat, not gasket, as they are not interchangeable designs. I have read a bunch of threads about plugs and found none that are really informative. So I will share this process.

I looked up the specs of each on the Champion website.

Here is the plug specifications for the OEM RE10PMC5: Thread Size: 14mm Hex Size: 5/8" (16mm) Reach: 25.4mm (1") Seat Type: Tapered Gap: .044" (1.1mm) Heat Range: 10 Terminal Type: Solid Resistor: Yes.

Here is the Plug Specifications for the RE7PYP6:Thread Size: 14mm Hex Size: 5/8" (16mm) Reach: 25.4mm (1") Seat Type: Tapered Heat Range: 7 Resistor: Yes

Looks like a match, except obviously the heat range is one step lower.

The double platinum looks like a better plug from the description, and good for time trial use (desire rapid heat up, minimal heat issues from extreme engine loads):
1) Tapered Electrodes Create a Sharper Spark Focus and Reduce Quenching,
2) Electrodes Use Heat-Active Alloy to Reach Operating Temperatures Quickly and Maintain Stable Temperatures Under Varying Engine Loads
3) Triple Sealed Interior, and Copper Core Reduce Failure Due to Heat and Stress.

I am going to the dyno as soon as I can get these plugs. Strange how few Champion plug dealers there are around here. I have to order them online.

 

[Boxer12]

Found a Champion rebate online: http://g-ecx.images-amazon.com/images/G/01/00/00/33/84/39/23/3384392370._V375135394_.pdf

Plugs found on Amazon and after rebate (good for $2/plug up to $40=twenty plugs) $4.85 ea (MSRP/Sears price over $12 ea).

sparkplugs.com has them for $6.75 ($4.75 after rebate) but I get free shipping on Amazon so that saved me $28.

 

[treesnake]

From the ACR-X service manual....FWIW


The ACR-X engine is shipped from the factory with the following spark plug: Champion RE10PMC5 – Mopar Part #05149164AA

As an alternative choice, the following spark plug is recommended. This is a colder plug and may perform better for high temperature race environments:
Champion RE7PYP6 – Colder Spark Plug (will need to be re-gapped).Both spark plugs should be gapped at 0.050” prior to installation. Installation torque is 14 ft-lbs.

I have been using this plug since last year in my '08 w/o any issues in the heat.

Engine mod list affecting heat;
-Ported heads/intake
-Mopar Perf. PCM
-Headers-no cats
-Motul 15/50 with Accusump
-ACR-X brake duct/radiator cutout on fascia
-PCV catch can
-"water wetter" in radiator
-manual rad. fan switch

 

[Steve M]

Thanks for this thread...very good info in here, including the spark plug rebate. I may pull a plug or two to see how they look...I'm assuming they'll read just fine since I don't use this car for racing at all, but it's good to know the recommended heat range for modded and/or tracked in high temps engines out there.

 

[Boxer12]

Treesnake, good find that confirms Winkel's advice...he prob wrote that in the manual.

Nice mods, btw. Heat is def an issue in your part of the country. Do you race? Track days? As an aside, one thing I noticed, you should change out your thermostat if you haven't already, to the Mopar race version as the OEM units all fail eventually (mine did).

 

[TrackAire]

Treesnake, good find that confirms Winkel's advice...he prob wrote that in the manual.

Nice mods, btw. Heat is def an issue in your part of the country. Do you race? Track days? As an aside, one thing I noticed, you should change out your thermostat if you haven't already, to the Mopar race version as the OEM units all fail eventually (mine did).

Boxer12,

Is the temp range the same, just a better quality unit?

Good work on the plug info!!

Cheers,
George

 

[treesnake]

Treesnake, good find that confirms Winkel's advice...he prob wrote that in the manual.

Nice mods, btw. Heat is def an issue in your part of the country. Do you race? Track days? As an aside, one thing I noticed, you should change out your thermostat if you haven't already, to the Mopar race version as the OEM units all fail eventually (mine did).

I'm just a weekend track hacker with a Viper (mainly a speed....) OCD....

Good point and yes, I have a 190* thermostat. I also removed the hood grills.





* I sent a PM regarding the manual in PDF

 

[tomfrancis]

We are using the Champion RE7PYP6 or stock number 7437 in the Viper ACRX race cars this is per Dick Winkles recommendation.


Tom Francis
SRT Motorsports