SCratching my head on this. Spark blow out? Options

[Justincredible]

what do your logs look like? knocking? o2's? ever thought about going coil on plug ignition?

[AWD DSM 1]

You mean that crazy thing's still running? I figured you would have blown it up a long time ago... wow... must have done something right for once... Great to hear!

[ncgalant]

what do your logs look like? knocking? o2's? ever thought about going coil on plug ignition?

I agree... Lets see a log

[JMoushon]

What Darryl runs. One coil on each plug, mounted on a plate that is essentially the same shape as the oem plug cover.

[awd4kicks]

I don't know how much time you spent Sat. night tuning, but Friday nights time frame was WAY too short to expect anything good. You have done a good job by double checking all your basics and doing 'your' thread sealer fix on the oil filter housing. Have patience and keep at it man...your going in the right direction but this sh!+ never happens over night an especially not in 1 hr. Get the freakin directions for your translater though it will help you keep a piece of mind.

[ncgalant]

Just please watch your timing. With big injectors you tend to get way to much.

[JMoushon]

Longshot, but is it possible that it is rich knock?

[natedogg]

Just please watch your timing. With big injectors you tend to get way to much.

As long as he's not seeing knock this is not a problem. And if he does start to knock he will see less timing, because the ECU will pull it. The more timing advance I get, the better my car runs. When you are running lots of fuel, you need more ignition timing to fully burn the mixture.

Nc, I think you should spend some time logging a 1G and watch the dependencies of timing on the knock curve. It may give you some insights as to why you run less timing when you run leaner. The timing curve is not based on airflow alone.

Not to mention, like Dan alluded to, one can't change timing independent of fuel with something like an SAFC or MAFT, short of adjusting the CAS. You'd need a standalone to do this because we're still dependent on the stock ECU.

[natedogg]

I don't know how much time you spent Sat. night tuning, but Friday nights time frame was WAY too short to expect anything good. You have done a good job by double checking all your basics and doing 'your' thread sealer fix on the oil filter housing. Have patience and keep at it man...your going in the right direction but this sh!+ never happens over night an especially not in 1 hr. Get the freakin directions for your translater though it will help you keep a piece of mind.

Good call. That exactly what I was saying on the phone last night.

I'm up for some tuning tonight Dan.

[ncgalant]

As long as he's not seeing knock this is not a problem. And if he does start to knock he will see less timing, because the ECU will pull it. The more timing advance I get, the better my car runs. When you are running lots of fuel, you need more ignition timing to fully burn the mixture.

I agree. Its just that when pulling out 40% of the airflow, if you don't show enough air to the computer to get it back into the stock ranges it gives way to much timing. I personally was getting 30 degrees of timing by 6000 before I learned how to tune for the timing I wanted. Granted this was at 12psi, but such high timing on pump gas and higher boost will lead to a very poor running car. Sure one can cover the problem with more fuel like I tried to, but in the end, this leads to many problems.

Nc, I think you should spend some time logging a 1G and watch the dependencies of timing on the knock curve. It may give you some insights as to why you run less timing when you run leaner. The timing curve is not based on airflow alone.

It is based on airflow alone if you never knock. I understand that knock is going to stop or retard timing advance. I also know that the octane variable keeps track of that.

Basicly, I'm saying the same thing I've said all along. As the boost gets higher, the timing should get lower. For the most part the ECU's maps take care of this. Large injectors with an ECU not made for those injectors just throw the ECU's maps way out of wack.

[natedogg]

I agree.  Its just that when pulling out 40% of the airflow, if you don't show enough air to the computer to get it back into the stock ranges it gives way to much timing.  I personally was getting 30 degrees of timing by 6000 before I learned how to tune for the timing I wanted.  Granted this was at 12psi, but such high timing on pump gas and higher boost will lead to a very poor running car.  Sure one can cover the problem with more fuel like I tried to, but in the end, this leads to many problems.

This has not been the case on my car. Granted I am usually tuning on 100 octane. But even tuning Dan's car on pump gas shows that the more timing we got without knock leads to more power. Its easy to feel in the seat of the pants.

Basicly, I'm saying the same thing I've said all along.  As the boost gets higher, the timing should get lower.  For the most part the ECU's maps take care of this.  Large injectors with an ECU not made for those injectors just throw the ECU's maps way out of wack.

As the boost gets higher and the fuel curve more agressive we have more matter to burn in the combustion chamber and therefore need to advance the timing to burn all of it efficiently. The stock ECU isn't built to do this, so in part I do agree with your last statement. It was built for a 200 hp car. If you ever get a chance get on evolutionm.net and pm Buschur how much timing he runs with his AEM unit at the 40+ pounds of boost that he runs on his race car. I can't make any guarantees, but I bet you its 30 degrees of advance or higher.

[wortdog]

IMO, The biggest reason Buschur runs lots of timing is the revs. On the Formula car, we saw about a 12hp difference between running 30 degrees of advance at 11,000 rpm and running 48 degrees of advance. This is on an engine with 12.1:1 compression that only makes 83hp total due to a restrictor, so I guess its not really a good example.

The way I think about it is that as the engine turns faster, you have less and less time to get the burn done in. There is also a constant factor of how long it takes from when the ecu tells the coil to fire to when there's an actual spark at the plug. The density of the mixture only comes in as a small factor compared to the size of the bore, as the biggest problem is getting the flame front to spread equally and quickly. This is one reason people have started running a second set of injectors in the intake runners close to the plenum, as the extra time before it gets to the cylinder helps promotes atomization at very high engine speeds/air flow rates.

If I had to guess, I'd say Buschur's timing table peaks out at around 38 degrees of advance at 9k rpm, assuming that's where his peak power is.

Those of you revving past 7k on the stock ECU would probably see gains if the advance map kept going up instead of peaking out.

Slightly off topic, but the interesting thing about dyno tuned fuel and ignition maps is that the torque peak is always right at the point in the fuel map with the largest injector pulsewidth, while the horsepower peak is generally right at the highest point in the timing curve.

[natedogg]

That's some good info Eric! I was thinking the same thing about the decrease in time for combustion as the RPM's increase after I posted. I was doing some tuning and noticed how my timing curve advances as my revs increase even to 9K RPMS.