CYL temp question

Multi stage Nitrous motors,
I was reading on another site that the NOS guys get their temps up to 1700 degrees. My knowledge is limited to NOS motors but how is it, that we'll have melt down above 1200 degrees on our blower motors and they can get away with those temps. Our pistons and their pistons are made from the same aluminum. Regardless of their incoming charge is waaaaay cooler than our motors but 1700 degrees is still 1700 degrees. or is this just a crock of shit?

 

They are burning fuel out the exhaust. With like 0 lead with all the stages in. I've heard of people just starting out with nitrous add fuel because they seen the exhaust temp and burn evrything up. Its a funny deal.

Look down to my question to the a/fuel guys about exhaust temp when they put it on the high side. It goes from about 500 to about 1200-1400 when they put the fuel to it, before they even stage.

 

It's all about the temperature/pressure "within" the cylinder during the combustion event and during the first 90 or less crank degrees after TDC.

Beyond that, nothing else matters. Remember, it takes time for heat to radiate & conduct and affect materials.

This may sound like an over simplified answer, but, truly the whole game comes down to thermal/pressure management for those first few crank degrees inside the chamber. EGT's are simply "references" to what might have happened earlier.

 

That brings up another question,

Anyone logging cyl pressure either on the car or on the dyno?

It is my feeling that when they get really good systems worked out that this will definatly be the wave of the future of tuning. I mean if and when they get enough resolution to allow you to see pressure vs crank position on each cylinder on a car as it goes down the track the days of reading bearings will be over. With this kind of a system you could actually see the changes of peak pressure vs pressure duraition with different fuel, compression, timing, and boost, as well as being able to find a lean spot during a transition that will kill parts but is so hard to find with conventional equipment due to the time duration needed to get a reading.

Sorry the concept is so damn exciting it cause me to ramble....

Richard Gavle

 

Creech, you mis-red the graph. The engine was on the low side prior to -5.6 where you see the temp at a higher level while lean. When he put the fuel into the high side while staging, the temp began to slowly drop with the rich mixture to about 500 at "0". "0" is where the run begins. As soon as he "put it on the deck" you can then see the temp jumps to about 1300 in about .2 or .3 into the run.

 

If that was a run shouldn't thert be a reading on the g meter higher than -.027 and more fuel pres. rpm esc...

 

Me too, I've been studying those numbers, but in the "dyno computer simulation" world, Performance Trends Pro Engine Analyzer since '96.
I think Sellin has it on his dyno now.
Sellin, Gary
Bolivar, MO
417-777-2332
There's the spark plugs with sensors in them and than the drill a hole into your chamber ones. Sellin's is drill a hole type.

 

I had looked at them a few years back and it seemed the TFX ( thanks for the pm AJ 481) was pretty much the way to go back then. I was running a water cooled nitrous motor so drilling holes through the heads was not really an option and the spark plug ring adaptors did not have very good performance. I have a friend that has a dual plug head running alky, kinda makes it easy with that extra plug hole.



Richard Gavle

 

Creech,

In your original question, you asked what happened when you put an A/F from the low side to the high side. This process takes place after the burnout and during staging prior to a run. So, what was sent to you by the fellow was just a segment of the computer readout of this transition, which is prior to the run. He did not post a full run showing the egt throughout the run.

The warmup and transition that is shown negative is the time before the run. In other words the readout starts at about 5.6 seconds prior to the run. The run starts at "0" and he gave you a piece to about 1.2 seconds into the run. Follow the timeline on the bottom of the graph.

So, the gmeter read at the "marker" line (vertical white line) is -.024 when the car was actually rocking and rocked backwards slighly.

Steven

 

Spark plug ring adaptors,,,
I meant the plugs that have a psi sensor built inside them which took combustion chamber pressure readings.


The dual plug heads just make it too easy, too bad I don't have any BBC canted valve dual plug heads

 

There are companies which build and sell such systems (TFX is one such company), or you can even roll your own if you have enough logging speed and memory capacity.

You can't really view any meaningful data "live" and you can't use the data for live control of the motor either, because the large volumes of data have to be collected and then post processed into anything useful. There are systems which can be used "live", but they have way too many zeros in the price tag.

We will be measuring 8 channels versus crank angle, and a bunch of other stuff, one of these days if we can ever finish the build at this end. Seems there just isn't enough day left at the end of the day these days . Now if someone would perfect cloning so that we could all go to work AND at the same time play with our race stuff, then that would be great!.....