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Copper vs. Platinum...

S

soultron

New member
When I had 3.4 pulley with supporting mods(headers, intake, 180T, Overkill tune), I switched to al605's. But i still had KR(My rear manifold EGR tube split wide open, but I thought it was a good thing since it would suck in fresh air rather than recycled crap exhaust, which turns out to be very bad for KR...anyways). So I switched to AL104's gapped at .050". I noticed a big drop in KR, which I was happy about, but I also noticed a huge drop in performance and gas mileage. Currently I installed an S1X cam with new intense tune and saw a little KR at the top of second(still with the EGR being wide open). Just fixed the leak today. I expect to see zero KR now, but haven't tested yet. Bottom line, I was going to try running 1-step hotter plugs(AL605's) but a senior member recommended I switch to ac delco platinums and claims that it will reduce KR without losing performance or mileage...Can anyone verify this? I spent a lot of time searching btw and reading about plugs but still haven't reached a solid conclusion
 


not one person here recommended plats, they are trash in this engine. run AL copper 104's. your senior member pal was having a senior moment i think lol


wanna fix the kr? buy a tuner, or get a in car tune. caned tunes suck for this very reason.
 
EGR is fixed now, and I dont want to lose gas mileage is why I kept it. I was getting 15mpg before i fixed the egr issue, so i don't want to get any worse. With the 3.4 before cold plugs freeway i was getting way better. Platinums were stock in this car, I know everyone recommends copper, but I was wondering if anyone could testify to not losing power/mileage with platinum vs. copper
 
No platinum plugs. Factory plugs are 41-101 AC delco Iridiums, not platinums.

Even the high performance factory GM cars run Iridiums when stock.


Keep the copper plugs for a 3800. And running with that huge vacuum leak is just asking for trouble, you are need that fixed or blocked off.
 


Scotty I wish I had a tuner!!! Your rubbing it in! :th_crying2: lol Between the Cam and TEP trans I just ordered has left me broke for now. It'll be a few more months before i'm able to get a tuner
 
@Five...I'm mistaken iridium is what I meant. The Egr tube is now installed with no leaks. I didnt realize how bad it was before, BUT the fact that I only saw a little KR means with it being fixed I should be able to run a smaller pulley or increase timing right? In other words I had a major exhaust leak before and saw minimal KR so now I should be able to drop to a 3.2 or up timing to 18 maybe? I always monitor KR while driving btw
 
you not dropping any small on th epulley till you switch to e85 fuel, or get a ic.

as is its now, you either need more fuel up top, or less spark, pick one lol

kr is timing related. you see kr, the pcm is pulling timing to keep it from killing its self.
 
That's really not how it works.

Fixing a leak doesnt just straight lead to being able to run more boost pressure and increased timing. More often than not you decrease timing with added boost. But you have no idea if the fix you did will change anything. If you still see knock with the leak fixed, then you can't increase boost or timing. You have to find the spot where they mix, you might have to decrease timing from whatever you are running by 1-2º for it to be happy. But then you know that if you add more boost, that likely won't result it in being able to handle more boost with the same timing.
 
im trying to be optimistic, i was only seeing a little at the tippy top of 2nd with a a wide open egr. I was fixing a rear header exhaust leak at the same time, so im letting the rtv cure. But yes without any changes, I will test and monitor KR when the sealant has cured with the egr fixed. If I see even a little, then ill make no changes, but if I see zero, which I expect, then im adding timing or dropping a pulley and monitor again.
 


You will most likely not even notice a difference in fuel economy by removing the egr maybe 1-2mpgs. With that broken egr tube of course you were only getting 15mpgs, I bet your LTFT was pegged at 16.5 the entire time and you were probably throwing a code p0171 as well as other codes for the egr.
 
3.3 is reasonable and no i didnt throw any codes...i even had a misfire on cylinder 5 but didnt throw a code for that either(cracked plug). My ltft's were avg. -1 with the egr tube split completely in half, which means I probably have a really rich can tune...I was using torque app to verify, then suspected it was wrong and tested it on an updated snap-on scope and got the same results
 
3.3 in the dead of winter if its cold where you live. god's intercooler.

how longs the pcm in and the car running now since the egr tube repair? your trims are gonna take some time to learn before they are reading right.
 
The tune i got has po300 turned off but I'm not sure if that means individual cylinder misfires are deactivated as well, so that may be the reason i never got a misfire code on cyl. 5
 


soultron said:
3.3 is reasonable and no i didnt throw any codes...i even had a misfire on cylinder 5 but didnt throw a code for that either(cracked plug). My ltft's were avg. -1 with the egr tube split completely in half, which means I probably have a really rich can tune...I was using torque app to verify, then suspected it was wrong and tested it on an updated snap-on scope and got the same results
Click to expand...
How was your cel not flashing at you with all that stuff wrong?
 
300 is the random misfire code so the light dont come at idle, cause cams misfire at idle.


when you turn your key to just run, does the "check engine light" light up on the dash like it should?
 
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