corvet786c

Is it NGk's like the LS1's or diffrent?

dennis50nj

i race so i read the plugs often, so i use tr55 and just change them since they are cheap

RichieRichZ06

If your car is lightly modded or mostly stock ,the Delco plugs are the best. I have seen so many driveability issues recently with NGK's installed in reletively stock cars. I have swapped out NGK's for delco plugs in over a dozen cars recently for random drivability issues directly related to the plugs. Everything from P0300 codes to carbon tracking on the plugs.

I did a back to back comparison on Delco plugs vs NGK's in our LS2 Trailblazer SS and we lost 8 RWHP with NGK's. I still run them in the TBSS because it has a 125 kit on it, but I would not touch them in a stock car. I am running the AC Delcos in our Cammed Z06 without issue.

theofel

I have a real problem believing there is 8 RWHP difference when installing any plug with the right heat range. Let's see some dyno graphs. I would love this to be true...I certainely would like to see another 8 RWHP! Better than adding a Fast intake to my Bolt-on LS3.

NYC6

Im not buying it either.

RichieRichZ06

Here are the graphs. 1st run is baseline with stock plugs and no tune, 2nd is with long tubes, tune and NGK's, 3rd is back to Delco's with no other changes in the tune. I felt that after adding the LT's it should have picked up more so we were wondering why. We put the stock AC Delco plugs back in it to eliminate that variable and came up with an additional 8 RWHP.

NYC6

Theres some other factor at work here. Dont know what it is but Im confident you're not getting 8hp with just a plug change, unless theres a gap difference, wrong heat range, bad plug or something not quite the same from test to test.

RichieRichZ06

Gap was double checked, heat range was the same, part numbers for the application were verified etc. This is not my first BBQ

This is not the only time I have seen something similar. I work at a dealer and we see 30-40 forum cars a month, all with unique issues. Recently I have seen a ton of issues with aftermarket plugs and drivability issues. I only posted this for people to see facts, not some keyboard commando baised opinion with no supporting facts to back it up. Take it for what it's worth and if you don't believe it, no biggie. I am not going to lose any sleep over peoples doubts on this issue when I see it on a weekly basis.

dennis50nj

that plugs brand new out of the box, diferent brands could make a big diference, im not sure on the dyno numbers but i have seen .15 gain at the 1/4 and also a loss of .30 with less then a 100 street miles on some brandsi have never had a problem with the ngk, i always just coat the iner spark plug boots with a qtip and dielectric creme

RichieRichZ06

.15 gain or loss would account for about 8-10 HP, which would be consistant with what I found. Both of the sets of plugs were brand new and the gap was checked just to eliminate that variable.

The only reason that made me think to do this comparison was seeing so many recent issues with aftermarket plugs on Corvettes. Using that logic on the LS2 TBSS, this is what i found.

The dielectric grease is a good idea to keep the boots from sticking on the plugs as well.

LS1LT1

Mez

In my opinion, the AC Delco plugs are just as good if not better than the other spark plugs on the market. I don't believe thereis anything to be gained by change them out to another brand including NGK for a stock or mildly modded engine.

Mike's LS3

Are we talking about Delco's iridium plugs? How often should plug wires and plugs be changed for optimal performance on a stock LS3? I know the owners manual states 100k miles. Did the 08 LS3's come with Delco iridium plugs? Thanks for any response.

RichieRichZ06

Yep, the stock Iridium plugs. I change mine every 10k miles, but that is excessive. We beat the **** out of our car every chance we get including Auto-X, HPDE's and drag racing so I like to keep them fresh.

Depending on driving habits, racing etc, I would change them every 25k on a mildly modded engine or less frequently on a stock one. I see cars come in here with 50k-75k on stock plugs and they still run great.

LS1LT1

The factory/stock Corvette AC Delco plugs are Iridium?
I thought they were Platinum but I guess not.

RichieRichZ06

They have been Iridium for years.

theofel

If that dyno graph is from a LS3 with the mods you quoted...those #'s are about 60 t0 85 hp shy of what they should be! Even without mods they are 35 t0 50hp off. I'm willing to give the Delco another try when I change out my NGK tr55's. Thanks for your input.

RichieRichZ06

In the previous posts I stated the dyno graphs were from my LS2 Trailblazer SS with Long tubes and cold air.

Gering

Brisk USA plugs work great for me.

IrishC6

I just had longtubes and cam installed on my 08 C6. Would the delco's still be OK for this application?