god910 Posted February 8, 2004 Report Share Posted February 8, 2004 Okay, let's settle this once and for all. Are they worth the money? Also, what would you expect to pay for some? I have seen them $12 all the way down to $6.50. That seems cheap if they are as great as they are hyped upto be. Next, what part number? My cross ref. for an R42LTS shows a TR5IX (which is the Iridium Xtreme ref. from a TR5, , which is the NGK ref. from an R42LTS as stated above, all of this is based on the R42LTS being the stock plug :x Which is what was in the car when I bought it, so that's what I'm going w/) But in another thread someone said they were getting TR6's. ASSumably, that would be a hotter plug, No? Next, plug gap: I was told by the P/O to gap them at .035". Some are saying .040", some .045". (Don't forget this is the manual chip, so Kenny might be able to say for sure, or Luke... What do you gap at?) I just want to lay all this down so that in the future people can use the search function (as I TRIED, but couldn't get engough info) to dissolve the situation. Blah, blah, blah. Quote Link to comment Share on other sites More sharing options...
Jeff M Posted February 8, 2004 Report Share Posted February 8, 2004 First off R42LTS is the proper stock plug for the TGP and TSTE, cooler than the R44LTS(?) NA engines run. Stock gap for us was .045â€Â, but when chip’d can get blown out at high boost/low loads so .040†was used and worked with no problems ever again (even when I was running 17 to 18 psi and 100 octane for 3 months). Old RapidFires that were NOT platinum came .035†and ran as well as stock at .040â€Â. Back when I did my research knowing the 42 heat range, the NGK Iridiums came up with just like you said and a few others I know that got these: TR5IX. The big thing with Platinums was long life (not good at high heat and passing high volts, something our TGP does/needs) Iridiums offer this longer life without the Platinum's penalties, but more importantly, the Iridium’s have a very fine tip, this makes for a more localized/intense spark, better for lighting off dense highly compressed air/fuel mixtures, and much better at repeatability of spark induced burn rate and a more control flame front propagation/smooth consistent power! Something that can bite you in the butt is to assume other manufacturer’s heat range systems, STUPID AC Delco reversed its heat range numbers for the RapidFires, a number 8 is colder than a number 6, dumb, dumb!!! I don’t have the list in front of me to confirm NGK but just know to check when looking at any manufacturer, easy since NGK details out their heat ranges to numbering system. Now the books say when you start to really crank the boost, you should drop another heat range or two, sacrificing some cold running driveability, but when I was running the 17 to 18 psi and making a lot of heat (stock turbo and stock intercooler, BUT did not run in air temps above 70 degrees!!!) there were no problems i.e. pre-ignition (not "detonation"). 1 or 2 steps colder might be a good idea, especially if you are in hotter climates, but chip’d TGP owners running in 100-110 degree weather never had problems so not a real issue yet, but when we start upping the air density and making more powerful/hotter explosions with turbo upgrades etc, might become an issue, that can be taken care of. Forgot the Denso Iridiums/$$. They have an Iridium ground strap to go along with the Iridium center tip electrode, more better costs more money, should not be a major difference in the spark being any less finer, but there will be a lot less wear of the ground strap being made of Iridium, but I am a firm believer (as many are) to not be afraid to pull the plugs and clean and re-gap, THAT is a good time to check out how things are going on inside your engine, call it a Check-Up from the Doctor-in-the-House. Jeff M Quote Link to comment Share on other sites More sharing options...
RareGMFan Posted February 8, 2004 Report Share Posted February 8, 2004 in another thread someone said they were getting TR6's. ASSumably, that would be a hotter plug, No? That would be me. I decided on the TR6's because someone on either this board or the TGP board called NGK and spoke directly with a rep who said that that would be a better choice for our applications because it's actually a heat range colder. Maybe they're following in Delco's backward footsteps. *shrugs* Quote Link to comment Share on other sites More sharing options...
brian89gp Posted February 8, 2004 Report Share Posted February 8, 2004 Yea, NGK's range is backwards. 6 is colder then 5, they recommend that you go 1 step colder for each 100hp. TR6 is as cold as you can go without going to racing plugs. Quote Link to comment Share on other sites More sharing options...
Jeff M Posted February 8, 2004 Report Share Posted February 8, 2004 Yea, NGK's range is backwards. 6 is colder then 5, they recommend that you go 1 step colder for each 100hp. TR6 is as cold as you can go without going to racing plugs. Sweeeet, good info, thanks!!! Just one step colder should be fine, a little insurance is good! TR6 should be good for 350 hp easy! Jeff M Quote Link to comment Share on other sites More sharing options...
brian89gp Posted February 8, 2004 Report Share Posted February 8, 2004 Only problem is extended idling or low load situations. The 3.4 DOHC uses the same plugs stock as the TGP does, I'm running TR6's right now and they get real cranky if you let it idle for too long. A nice agressive romp is usually enough to burn the crap off. Quote Link to comment Share on other sites More sharing options...
Jeff M Posted February 8, 2004 Report Share Posted February 8, 2004 Only problem is extended idling or low load situations. The 3.4 DOHC uses the same plugs stock as the TGP does, I'm running TR6's right now and they get real cranky if you let it idle for too long. A nice agressive romp is usually enough to burn the crap off. We might be ok with our 3.1L, but good to check the plugs after a time. Ours "might be ok" since we have Swirl Heads and you got Tumble, each has its pros and cons like anything 8). We have higher intake temps even idling and cruise maybe this will help too, tests will tell/confirm. Jeff M Quote Link to comment Share on other sites More sharing options...
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