If it was a clogged fuel filter, wouldn't ALL the pistons be melted because not enough fuel is getting to all cylinders? If your positive it's the fuel system, then it almost has to be 3+4 injectors, right?

 

Just because 1 and 2 look clean on top, does not mean you won't discover damage when you remove them.
Most all piston damage is caused by too much timing. It takes heat to melt a piston. If you have a cloggged injector, you cannot get the cylinder hot enough because of no fuel. But if you have plenty of fuel with too much timing causing detonation, that is where the problem starts.

 

Say the battery or alternator was starting to weaken though and you were using 1600cc injectors (running lower battery voltage)...even up top wouldnt you see much more drastic effects with a larger size injector?

People dont use an injector driver box just to get constant fueling at idle right...is does help all around the rpm range.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">The size of the injector has nothing to do with how hot it will get or how much load it will put on the injector drivers. The resistance is all that determines that, and most 1600's are around 4.5 ohms, pretty high for a peak and hold inj. The problem running them w/o a driver is at low rpm the opening time is so short, that it's hard to get good consistent fueling.

For what it's worth, i've done 1600's w/o a resistor box with hondata w/o problems.</TD></TR></TABLE>

 

but battery voltage should be a constant. if you have an injector driver or not, low battery voltage would affect the injectors.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">Just because 1 and 2 look clean on top, does not mean you won't discover damage when you remove them.
Most all piston damage is caused by too much timing. It takes heat to melt a piston. If you have a cloggged injector, you cannot get the cylinder hot enough because of no fuel. But if you have plenty of fuel with too much timing causing detonation, that is where the problem starts.</TD></TR></TABLE>

Well aware of this, but its obvious 1/2 were fine. I see no vertical scratches in the cylinder wall, no signs of detonation, no signs of anything melted in those cylinders.

Timing was CONSERVATIVE ON THIS MOTOR, the questions was can TOO LITTLE timing cause EGTs to get so high it can melt stuff.

Lets say there was too much timing. Why would it only affect 2 cylinders, almost destroying those 2, yet the other 2 were fine. doesnt make any sense ot me.

the only thing i can think of is that some how, fuel was cut off to those 2 cylinders, in the middle of a 27psi pull, an it got hot.

so what happens if the car was running fine got into boost, was making a pull , an the fuel cut off or leaned out , dropped pressure, at the top end of the pull. while in boost. would that THEORETICALLY be enough heat to be caused to melt a piston. IMO yes

 

an injector malfunction will cause enough heat for one piston to melt... done it before

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">If you have a cloggged injector, you cannot get the cylinder hot enough because of no fuel. </TD></TR></TABLE>

I was waiting for someone to post that....
People are quick to blame clogged injectors.
If an injector is clogged that means you have no fuel. With no fuel you can't have flame. Without flame you can't melt anything.....
There's has to be enough fuel to get a fire otherwise you'll just have spark in a dry hole.

Clogged fuel filter would still allow fuel to get thru but you would see a drop in fuel pressure. This could cause a lean condition...

Also as tony1 stated earlier engines in this power range don't need much time at all to melt pistons. It could happen quite quickly.

Without looking at the parts it's almost impossible to try and figure out what happened...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">an injector malfunction will cause enough heat for one piston to melt... done it before</TD></TR></TABLE>

a leaky one, yes..

If it's clogged it can't..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jared &raquo;</TD></TR><TR><TD CLASS="quote">but battery voltage should be a constant. if you have an injector driver or not, low battery voltage would affect the injectors.</TD></TR></TABLE>

But battery voltage isnt constant, thus why we have battery voltage tables in the code.

This is especially apparant on an electrical system that is beginning to fail...before the actual battery light comes on in the dash.

 

EGT shows lean/rich on a bell curve.To much fuel also looks like not enough. Retarded timing burns most of the mix in the pipes and give a high egt.This also would cause a big drop in power but I doubt it would cause any piston damage. A "sometimes" working injector is a problem, and a "never" working injector won't do any damage.

 

Couple thoughts:

1. Fuel filter / clog hypothesis: which side of the fuel rail was the feed on? If it was on the stock side (passenger/cyl4) you would expect to see 1-2 leaning out NOT 3-4 as happened.

2. Hate to say it, but what version of the core Crome tools (FuelTools, RevTools, QuickDL, etc) are you useing? This + how you have the bin setup can make a huge difference in how the car operates.

3. Don't discount the marginal alternator / electrical system pre-failure. This can make a HUGE difference with big injectors, and an equally huge difference with big pumps. With shitty battery tables, I've seen a snapped alternator belt cause a 2.0 AFR shift (11.x to 13.x)

 

The fuel feed is on the passenger side of the car. I also know that the battery is brand new and the alternator is a couple years old.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NJIN BUILDR &raquo;</TD></TR><TR><TD CLASS="quote">EGT shows lean/rich on a bell curve.To much fuel also looks like not enough. Retarded timing burns most of the mix in the pipes and give a high egt.This also would cause a big drop in power but I doubt it would cause any piston damage. A "sometimes" working injector is a problem, and a "never" working injector won't do any damage. </TD></TR></TABLE>agreed, that is why I am suggesting there was an excess timing issue involved here
It almost looks like there was a head gasket issue with the 2 good looking pistons. They look like they were washed clean and perhaps stayed cooler than the 2 hurt pistons.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by josh green &raquo;</TD></TR><TR><TD CLASS="quote">The fuel feed is on the passenger side of the car. I also know that the battery is brand new and the alternator is a couple years old.</TD></TR></TABLE>
Fuel filter clog is out for me.

If you get bored, take the alternator to your favorite parts store for testing. See if you can watch them test it so you can observe exactly how much voltage it puts out. Be concerned about anything less than 14.0 - really should be more like 14.5 - 14.9.

I'd still bet money that the damage was already done (or at least started) prior to that 1/4 mile pass. Either that or the car saw some cells on the track that it didn't see on the dyno - you do have a non-loading dynojet, right?

 

i dont think ive ever seen an alternator test that high?

 

I am leaning more towards fuel filter problems or lack of fuel supply. Let me know if this makes sence. The regulator is at the #1 end of the fuel rail and the regulators job is to restrict flow and increase pressure. This means that the pressure in the supply side starts at the regulator and works back to the pump. IE no regulator no pressure. Since the damage gets worse from #1 to #4 it makes me think there was a lack of fuel supply.

I am ruleing out tuning because the car has made tons of runs at higher power levels then when it blew. Car made at least 8 passes that day before it let go and was getting faster each pass (unlikley motor was hurting each pass) and the pass it blew up was the fastest of the day at same boost level. If tuning was the case, I don't see it lasting as long as it did and then do as much IMMIDIATE damage as it did. Plugs were checked multiple times and never showed any sign of det. If you look at the pics 1 and 2 are perfect and the cylinders and ports were dry. No HG problem in those cyl.

I am very interested in the low voltage idea but still not sure why only 2 cylinders were damaged and one being worse then the other.

Also, going to check the ecu about the injector drivers. Can only one or two of the drivers go bad causing those injectors to lean out?

Like someone said the #3 and #4 cylinders had to lean out or det. and not just have the injectors quit. No fuel, no flame, no damage. Not much fuel, too much heat, too much money to fix.

Later, Charles using Mike logon

 

NO alternator should charge over 14.7, anything over that is enough to blow up a battery. MOST alternators read 14.0-14.2 in perfect condition.

 

since the car was getting faster each run, what was the temperature doing outside during the day? Was it dropping drastically? car getting faster could be due to going leaner with the cooler IATs, which eventually lead to the meltdown.

or could be some other fuel supply issue.

it is strange its went down the track 8 times and then 9 is the magic number to pop. Kind of why i was wondering about fuel levels, or octane levels.

my car hated the sunoco 110 octane i had in it this weekend, over the normal citgo 110 or VP c16.

 

it was getting faster and faster beucase it was my first time with the car and i was learning how to drive it more and more and at the same time trying to dial the boost controller in to the max boost which i didnt get to.

 

I think the reason it was going faster was because Matt was getting better launches. This was his first true time at the track with his new car and new slicks. The trap speeds were pretty close all day (between 134-137 all day) and the ET's were dropping each run.

Weather was pretty constant all day. May have only cooled down about 5-10 degrees. Car has air to water intercooler so IAT are pretty constant (at least on all the dyno runs which were datalogged).

I am still thinking INSTANT lack of fuel.

Charles

 

I'm betting the injectors 3 and 4 got hung up.
I would also check the resistor box.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VtecKiDD &raquo;</TD></TR><TR><TD CLASS="quote">I am leaning more towards fuel filter problems or lack of fuel supply. Let me know if this makes sence. The regulator is at the #1 end of the fuel rail and the regulators job is to restrict flow and increase pressure. This means that the pressure in the supply side starts at the regulator and works back to the pump. IE no regulator no pressure. Since the damage gets worse from #1 to #4 it makes me think there was a lack of fuel supply.
</TD></TR></TABLE>
Backwards. I've had issues from clogged filters. I've had issues from bad pumps. In most cases, I've caught it before any permanent damage happened by looking at the plugs and getting scared from how different they looked. The rest of the time it was always the cylinder(s) furthest from the fuel supply line that were worst off, not cylinders closest as was the case here.

There are still plenty of things that can be done (or omitted) in Crome to cause a car to run wonderful in 4th gear (i.e. on a dyno) and run like **** / detonate in other gears. If you want the bin looked at, I'm an unbiased outsider that either wrote or had a hand in writing most of the tools your tuner was using - I know what to look for.

 

not to knitpick but 134-137 isn't a 650whp car either.. what kind of dyno was this tuning done on?

when was it tuned via dyno versus when it went to track

 

Dynojet with 24" roller

But the car was tuned with a different boost controller. You have to remember he was messing with the boost controller every pass and it never read over 27psi in the datalogs. Lets not start nit picking the trap speed and ****, the car is not even setup. Car was running high tire pressure and nothing is really setup yet. We just wanted to make sure it was running well and make sure the car would make it down the track with no problems OTHER than the engine, like brakes, fresh tranny shifting well, etc...

 

that could be your issue there, I assume the dyno was the standard dynojet without the new load bearing feature.

if the car was only tuned via dyno, could have hit a few cells not caught by the dynojet during the tuning and a lean spike could have occurred. Although it would have to be one hell of a lean pocket, as detonation takes time to kill a piston, doesn't happen in a one shot run, without something else failing.