dannyz

So I had been running a 125 shot on a nitrous outlet wet plate for a few years.
So last sep. I swapped out the BR6ef plugs for a set of BR7ef's, put in jets for a 150 shot,62n/31f, had my tuner pull a total of 6 deg timing, and went to the track.
Made just two 1/4 mile run's and was taken off the track, [no 6pt/fire jacket].
So I drove the 160 miles home.
have not used the nitrous since, and have driven the car at least 3,000 miles since.
Decided to put in fresh plugs and was shocked when I pulled #2.
Ground strap completely burned off and its missing a small chunk of the ceramic from around the electrode.
The other 7 plugs are fine?
Anybody have any ideas what to look for first?
What are the odd's that the missing sparkplug pieces just blew out the exhaust valve without hurting anything?
Car runs/feels just as good as it ever has but am going to do a compression test to be sure.

tug686spd

iTrader: (11)

I'd first run a compression test on that cylinder and a couple le others to see where it's at in comparison. Could have a clogged or partially clogged injector. Compression test will tell you if you have to dig farther into motor. If motor checks out fine then it's time to test your tunes and see why that hole got so hot.

dannyz

I didn't think about a clogged injector.
Thanks

erskine

iTrader: (5)

what type of gas you running? and afr on the juice?

tug686spd

iTrader: (11)

Seems odd that a plate that worked without issue for years on a 125 shot would have problems with a 150 shot. That's why I'd look elsewhere for the problem.

dannyz

92 oct/ afr was 11.3-11.6

dannyz

That's what has me perplexed.
Timing is what causes the type of detonation that I had, but none of the other 7 plugs had any sign of it.
I am pulling 6 degree's, and maybe for my car that's not enough for a 150 shot, but like I said, I had been using the 125 jets for the 3 season's prior.
I am wondering if maybe some oil was getting into the cylinder somehow?
There is no sign of any on the plug though.

baronsmith98

iTrader: (2)

What is your actual timing?

dannyz

22 deg's is what my tuner say's

pantera_efi

iTrader: (1)

Hi, I would like to see a picture of the other sparkplugs.

The Spark Instant is too soon.

Most often the first cylinder to show the problem will continue to pre-ignite with the MOST damage that the plug.

Lance

Bowtiedford

iTrader: (9)

sounds like either better fuel octane or less timing. I went thru this many times on my car till I figured it out. 150 I went to a standalone for race gas and timing went down to 18 if I remember right. timing marks on straps?

subeone

iTrader: (5)

too much ignition timing.

shortdog

iTrader: (1)

^This... and 11.3-11.6 is rich.

AJatNitrousOutlet

The best way to find out what is going on is to put a fresh set of plugs in, make a single pass then pull the plugs and see how they look. That would help isolate the problem, but either way that cylinder is getting a lot of heat in it. Running a single pass would let you know the how the fueling and timing is doing, and help get you the info to get it tuned in.

dannyz

A pic of the remaining plugs won't be much help.
I drove a bit over 3,000 miles on them since I last sprayed.
Had no idea that I had burned up the plug, so never checked.
Had 3 seasons running the 125 shot w/o issue, so didn't think another 25hp would be any concern whatsoever.

dannyz

Man. Given the damage that was done to that plug on just two passes, I am real reluctant to do a full 1/4 mile run w/o some idea of what went wrong.
Would an 1/8 mile pass be too short a run to get a timing mark?

jblankenship

iTrader: (5)

No, 1/8 would be fine, pull more timing before the next pass.

Bowtiedford

iTrader: (9)

exactly, pull a little more timing. I went a 6:80 on a plug that the electrode was missing, and drove home and then the next day I checked and was like what the,,, amazing it ran so good lol. it's just the extra 25 was what caused to break the camels back lol. Mine was 150 going to 200 took forever to get it right, 2 steps colder plugs and race fuel in stand alone and timing down to 18*. every car is a little different on the setup and tune but the basic rules apply to all.

Bowtiedford

iTrader: (9)

plus that plug wasn't to bad lol, I've done 3 on 1 pass, rather melt plugs all day then hurt a head or something else

try 18*

brandon@nitrousoutlet

iTrader: (2)

It sounds like you've found your hottest cylinder. I would pull it down 4 more degrees or so, while you're figuring this out. Can you give us some more info on your setup? What does the fuel system consist of?