Spark Plug Help on Built Engine with Paxton

[jmillsUT28]

Needing to change my spark plugs before my dyno tune. Have some questions on which plug will work best for me. The car is a 2002 that has a built engine from Underground Racing with a paxton setup. Really do not know much about it has I bought it from a dealer and underground is not helping me with getting the info showing what they did to the engine. But they did say they did a full build on it. The plugs that are in it are the Bosch Platinum + 4 4428 with a heat range of 8. Not sure how long they have been in the car but they look really bad. The car runs like crap until you have driven it over 5 minutes. After talking to a few people and doing some searching on this site this is what I have found...

NGK R5671A-8 4554 Heat Range 8
NGK ZFR6F-11 4291 Heat Range 6
NGK BKR7E-11 4644 Heat Range 7

Wish I could give you more info about this engine but Underground is not helping me. Which plug would you install in this setup? I might just buy a set of each as they are not expensive and see which works the best.

P.S. This is not a tracked car.

 

[sniper1]

I strongly reccomend stock or close to stock plugs and NO platinum or multi pronged plugs ever. The platinum plugs are known to cause detonation and really work best in N/A enigines with anvanced timing. Boosted engines need cold plugs and reduced timing to run properly. Your car is probably running bad because of the current plugs I'd bet. I always run stock plugs and never have any issues.

 

[jmillsUT28]

What heat range are the stock plugs? Which ones do you use?

 

[SquadX]

Tator recommends the stock plugs also.

 

[99 R/T 10]

By Champion's number, the stock heat range would be 12(RC12LYC for 1992-2002 cars and RC12ECC for the 2003-2006 SRTs). If I remember right, Daniel Lesser and others seem to think the newer plug for the SRTs are a better all around plug and will fit all cars from 1992-2006.

 

[plumcrazy]

NGK BKR7E-11 4644 Heat Range 7 is what i was told to run but i dont know how much colder it is than stock.

anyone know ?

i have heard daniel say that about that SRT plug.

get a call into greg good and see what he says too

 

[sniper1]

By Champion's number, the stock heat range would be 12(RC12LYC for 1992-2002 cars and RC12ECC for the 2003-2006 SRTs). If I rememebr right, Daniel Lesser and others seem to think the newer plug for the SRTs are a better all around plug and will fit all cars from 1992-2006.

Yes the plugs are Champions RC12LYC. I'm not sure about the ECC plugs but I think they are a one step hotter plug in heat range.

 

[Viper Specialty]

Yes the plugs are Champions RC12LYC. I'm not sure about the ECC plugs but I think they are a one step hotter plug in heat range.

No, the are the SAME heat range, but the the ECC has a copper ground electrode, making it less detonation prone.

 

[MTGTS]

One step colder than stock with boost

 

[Viper Specialty]

Without knowing what kind of power the car makes, and what was done to it, all the details... this is a tough question to answer. Though I certainly do agree with staying away from platinum plugs in Vipers, they always seem to cause more trouble than good on just about any application.

 

[jmillsUT28]

Hey Dan, so should I get the RC12LYC plugs? I'm a Champion dealer and my supplier has them in stock but they do not have the RC12ECC plugs. I got a heck of a deal on this car and only bought it because Underground said they built it. It was a gamble but I took it. Thought they would help me out a little more with info but... Just something I'm going to have to deal with.

What heat range are the stock plugs? 6?

 

[99 R/T 10]

No, the are the SAME heat range, but the the ECC has a copper ground electrode, making it less detonation prone.

This is why RC12ECC is better.......................................

 

[jmillsUT28]

Mike what the heck is the heat range on those?????? ha

 

[99 R/T 10]

the "12s" is the stock eat range. But each manufacturer is different (how they number and rate their plugs). On your car, a one step colder plug would probably be safer, so look at NGK 4554s.


On that note, does anybody else have a recommendtion on spark plugs? One step colder than stock for the young man please............................

 

[Fatboy 18]

I had the bosh + 4 plugs in my car, the car after a while threw up a code light. misfire! When I took out the plugs they were horrid they had a fairly even clean burn on them but the centre electrode had almost vanished on some of them! I went back to Champions OEM plug, coor the car goes great now

2000 GTS

 

[jmillsUT28]

Here's a picture of the Bosch Platinum +4, then the NGK R5671A-8, and then the NGK BKR7E 4644. As you can see they are different lengths. Just thought I would post this pictures.

 

[Joseph Dell]

The 5671A-8's (aka: 4554) are a good plug. I ran it for years in my SC set-up and run it now in my TT set-up when running low-boost.

good luck!!!

 

[jmillsUT28]

Hey Joseph, the 4554 are pre gapped to .032. Should I leave these at .032 or go to .031 or .030? Thanks for the reply!

 

[Viper Specialty]

Still waiting for an answer as to how much power this car makes?

 

[Dan Cragin]

NGK4291 works well with boost up to 15psi.

 

[jmillsUT28]

Hey guys, just got some info from UGR. This is what they remember doing to the car.

- Paxton Supercharger
- Pulley upgrade
- Ported cylinder heads
- Forged rods and pistons
- 8:1 compression
- I recal it having either 55lb or 65lb injectors with upgraded fuel pumps/system/rails
- Stock transmission swap

I have no clue what kind of power this car is making. Hoping to safely find out this Friday...

 

[plumcrazy]

8:1 seems low.
Wonder how much head work was done.

Is there a way to tell of you have strikers ?

Sounds kinda vague to me.

 

[jmillsUT28]

Yea I know. Do the strikers have any kind of markings on them that I might be able to see?

 

[jmillsUT28]

Now this car sounds like it has a lumpy cam in it. So maybe it has a different cam too but I do not know.

 

[plumcrazy]

The typical Proline built engine does have a lumpier cam than the 708

Greg good can tell you how to identify the heads I'm sure.

 

[uvbnbit]

Can the dealer not give you any previous owner info so you can contact them for build sheet/specs? Just a wonderin'

 

[jmillsUT28]

Long story but the dealer got this car on a business deal gone bad where this car was part of some other assets as collateral. So the previous owner would not be happy to talk to me... lol Wish it would be that easy.

 

[Joseph Dell]

Hey Joseph, the 4554 are pre gapped to .032. Should I leave these at .032 or go to .031 or .030? Thanks for the reply!

.032 is fine. if you are running more than 16psi and find that you are blowing out the spark then you can re-gap. but .032 is fine for a paxton's 15-16psi.

BTW - Proline (as any good engine shop) would keep a full build sheet on your motor. so call them and get it. If you don't know who the previous owner was, run a carfax. that will have the info. then give Proline the name and they should be able to help you.

good luck!

 

[plumcrazy]

Tator or a dealer can get you owners named too.

 

[jmillsUT28]

Doing a carfax today and will be calling Proline. I hope they can help me out with this. Thanks Joseph!

So I changed out the plugs last night to see if it helped the way the car was running. Well when doing this I found that the car has stock plug wires on them and they are all messed up! They have electrical tap on them covering up the wires that are sticking out of the insulation!!! Cylinder 6 plug wire was the worst. When I took the plug out you would tell that plug was not firing at all!! I'm glad I found this before I got to the dyno. Now I need to get some wires nextday air to me. Hoping AB has some in stock.