<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboGSR00 &raquo;</TD></TR><TR><TD CLASS="quote">Just the tip of the spark plug got melted off.... ill try and get a pic of it..</TD></TR></TABLE>

That's not good. Melted off....egt's had to have been up. Or shot up very fast. If that's the case. I blame timing. Just My opiniion.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboGSR00 &raquo;</TD></TR><TR><TD CLASS="quote">Just the tip of the spark plug got melted off.... ill try and get a pic of it..</TD></TR></TABLE>

Kind of like this.....?

 

Yeah looks the exact same................... lol

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tjbizzo &raquo;</TD></TR><TR><TD CLASS="quote">Either way, here are some tricks you can try to slightly improve #3

* if you have balanced and flow tested injectors, put the fattest one on #3

* adjust the valves .001-.002 looser than the rest on #3

* use a spark plug one step colder than the rest on #3

Any other ideas guys?
</TD></TR></TABLE>

are these some good options guys ??

i wanted to know, because if it is then ill go and buy 4 new spark plugs 3*the ones im using now and 1 spark plug a step colder ?

Greetz Erwin

 

The damage was obviously caused by detination but I think we have all concluded that many posts ago. Looking at the pistons, the area by the valve releif is the thinest part of the pistons. What happens is that if the cylinder gets hot, that is the first area to heat up and stay hot. This will cuase hot spots in the cylinder and if your motor is on the verge of detonation, then an excessivley hot area such as that can cause pre ignition which like stoopid said will lead to detonation. I have seen this happen alot and that is why most of the pistons you see today have the edges sanded down to get rid of the thin areas and reduce the likelyhood of hot spots from occuring. Good luck with the next project .

 

Im thinking its the combination of two things. Detonation due to timing, and the heavy load of boosting in 5th gear.

Isn't boosting 5th gear a big no no??

Khoi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by st00pid &raquo;</TD></TR><TR><TD CLASS="quote">I would think that number 7 NGKs at 12:1 AFRS for an extended period of time would start to get very hot and possibly cause pre ignition which on pump gas could very easily detonate. It looks as though part of the spark plug went through the valve. do you have a pic of whats left of the spark plug? As antwaine pointed out its a good Idea to run a car quite a bit richer if you know you are going to run extended periods of time in boost. good luck on the new build.</TD></TR></TABLE>

Stoopid, I have to disagree with you here.

DSM's run 7's on cars making up to about 500 whp, at over 25 psi of boost. Since knock monitoring is easy to come by in that side of the import world, everyone is using it. There is no noticable preignition coming from the plugs, at least not for us.

It's certainly a plausible theory though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboGSR00 &raquo;</TD></TR><TR><TD CLASS="quote">Wideband was hooked up and ran 12.1 a/f and temp was fine........ dont know what caused this to happen.... </TD></TR></TABLE>

This is exactly the line of thinking that gets a lot of people into trouble. The problem is that A/F ratio does not guarantee ANYTHING about the safety of the motor.

You could run 9.0:1 all the time, and I could still tune your car to detonate and blow up. A/F ratio is but one factor in a wide range of things that effect the way your motor runs.

I would look to timing advance and the heat of an extended pull for the reason this happened.

It's a bummer your ECU is not capable of a larger degree of knock retard.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sohc Driver &raquo;</TD></TR><TR><TD CLASS="quote">Im thinking its the combination of two things. Detonation due to timing, and the heavy load of boosting in 5th gear.</TD></TR></TABLE>

I agree with you here. Not to mention the fact that 5th gear is a longer pull (in terms of time) than other gears, and as such will allow more heat to accumulate.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Isn't boosting 5th gear a big no no??</TD></TR></TABLE>

I sure hope not, because if it is then my car has a 125 mph top speed.

5th gear is more load than all the other gears, just like fourth gear is more load than third. You just need to tune the car properly, and more conservatively if you plan on making extended high speed runs.