I think we are getting a little hung up on theory instead of facts. I have seen and alcohol motor with a broken INTAKE rocker arm have over 400* EGT. Does that not prove that we can increase EGT without the intro of fuel or oxygen through the intake valve. This is not an isolated incident as I have seen it on more than 1 car. Do I know what caused it? No? Do I care? Not enough to research it. The customer isn't going to pay me to diagnose his "problem" and the car isn't going to pick up any ET or MPH. Lets get back to the basics of what has been tested and what was the putcome of the test. Props to anyone running alcohol with consistancy and reliability.
Why use a distributor?
- Thread starter Alky V6
- Start date
You say you want to see some facts and introduce an incident without any supporting details. You're killing me!
Fact. Throughout this thread, I have offered up my actual experiences (not theory) with my project car. If anyone has anymore questions, ask away. Please try not to ask me what's already been covered in the thread.
I am definately not taking shots at you or your expertise. All of us have experienced things others have not. I am obviously not as technical as you but I do make cars go fast. Heck I would like to sit down and talk to you sometimes about methanol on one of these motors as i am considering doing a couple of them. What i was trying to say is that until you take your personal car, change it to a dist., put it on the dyno with no other changes and post the results we are just theorizing onthe EGTs. No flame intended
Look. I'm sorry if I'm coming off brash. I'm just starting to get tired of typing the same stuff over and over. If something is asked that has already been covered, I will ask you to refer back to the thread. I would like to have things keep moving forward.
About your observations of the EGT and the alcohol engine. I am curious:
What was the engine?
What style exhaust system? Short, long, log, tuned length, individual shorties?
EGT readings on all ports? And how far away from the port?
What type ignition system?
Intake setup? Blower? N/A? Turbo?
Was the exhaust valve on that cylinder still operating?
What were the cam specs like?
About your observations of the EGT and the alcohol engine. I am curious:
What was the engine?
What style exhaust system? Short, long, log, tuned length, individual shorties?
EGT readings on all ports? And how far away from the port?
What type ignition system?
Intake setup? Blower? N/A? Turbo?
Was the exhaust valve on that cylinder still operating?
What were the cam specs like?
Donthats just the thing, I amnot interestedenough to document the required information. 2 were 632" ford the other that I can remember was a 434" Ford all twinn turbo on methanol. The one I can that happened the latest and I can rember the most about broke an intake rocker arm (completely) and the exhaust was fine. That cylinder was reading appx 400 EGT while the others were 650-700 at idle. All cars had msd 8 boxes (the minumum box we can run on methanol). I had rather not talk about the cams. Once again we can theorize all we want but to most of us simpletons it is just glorified bench racing. Every car is differnt and maybe your egts wouldnt change a lick but I cant say that the next guys would not. i'm just not that smart or dont care enough to figure it out.
I'm not familiar with the MSD products enough to know what the 8 is. Is that a single coil and distributor deal?
What's the problem with the other boxes on methanol? Ignition missing?
This is actually what I see as part of the problem. People not caring enough to get a reasonable explanation for a condition.
Someone notices that EGTs were higher with a waste spark system than they are now with a distributor system. The rumor starts to spread that waste spark systems cause higher EGTs. No explanation given. Now everyone has a reason to condemn waste spark systems. Higher EGTs. That's it?
Without attempting to explore the reason for a change in a condition, you end up tying a product to the witches stake and setting it on fire, while newcomers in the gathering crowd are asking, "Why are you burning that?" The other person answers, "Heck, I don't know. Higher EGTs, I guess. Go ask him."
Mike Licht brought up something interesting. He said that, for whatever reason, an 'improved ignition system, distributor or otherwise' ends up adding 2 degrees of effective advance to the spark timing. I don't understand why that can't be adjusted for, but oh well. He concluded that's where the extra hp gain is coming from. Assuming that the extra advance is not causing detonation, I can see that happening.
What I also see it doing is affecting EGT. Retarding ignition timing will generally increase EGT. Advancing ignition timing will generally lower EGT.
Did I possibly just solve the 'waste spark causes higher EGT' rumor?
What I also see it doing is affecting EGT. Retarding ignition timing will generally increase EGT. Advancing ignition timing will generally lower EGT.
Did I possibly just solve the 'waste spark causes higher EGT' rumor?
So is there no effect? Some think 2 degrees is enough to affect hp enough, but not the egt at all?
"Without attempting to explore the reason for a change in a condition, you end up tying a product to the witches stake and setting it on fire, while newcomers in the gathering crowd are asking, "Why are you burning that?" The other person answers, "Heck, I don't know. Higher EGTs, I guess. Go ask him." "
An attempt to explore the reason for increased EGT's was done
Re-read the thread............
An attempt to explore the reason for increased EGT's was done
Re-read the thread............
Would it be possible that the reason for less EGT after going to a distributor is actually because of less of the supplied fuel being burned during the normal combustion cycle?
Less of the fuel being burned would give lower EGTs and lower cylinder pressures. The lower cylinder pressures would put you further away from detonation limits, which would allow more ignition timing. The extra unburned fuel would actually act as a chemical coolant, which is what rich mixtures are actually for. The extra fuel providing extra combustion cooling and the increased ignition timing could provide more horsepower from less fuel actually being burned.
A lot has been covered. I did actually re-read the thread. There are some lose ends to tie up.
I threw this post in to get you guys thinking. I was exercising my imagination a bit. I don't actually think this is what is happening.
I believe this is true. To add to this, during coastdown, the injector pulse widths are generally kept at a value near what you'd see at normal idle. During coastdown and very low manifold pressures, this causes an over rich condition and allows a lot of unburned fuel to enter the exhaust.
With the fact that we can see sporadic igniting of fuel in the exhaust system during coastdown in some situations, does that gaurantee that extra fuel is always burned in the exhaust system during normal acceleration? Assuming the car has no air pump installed, pumping air directly into the exhaust manifold near the exhaust valve, the answer would be no. That is what catalytic converters are for. During a smog test, if the catalytic converter is bad, you will see a rise in hydrocarbons. The hydrocarbons is fuel that is making its way out of the exhaust system. Unburned.
From what we've covered, I have to conclude that lower egts found after switching to a distributor is caused soley by the improved spark delivered by the msd box. Not the distributor. Any advanced spark timing can play a small role in lowering egt too. A quicker more complete burn due to a better spark would also increase hp, lower fuel requirements and would be seen as a leaner O2 reading.
I can tell you as a dyno tech for one of the big three : two degrees of timing will change the egts almost 100 degrees depending on how close you are to knock, peak cylinder pressure, ect.
I think what you are actully seeing is unused fuel not being burnt by a waste spark ignition , not an improved spark.
Yes. I think I see your point. Fuel and air that enters the exhaust system, partially burning in the exhaust system, raising the temps. Is that what you're suggesting?
If the a/f charge is burning in the exhaust, it would have to be only partially burning, otherwise if the whole mixture burned in the exhaust there wouldn't be any oxygen for the O2 to read. We all know that missing cylinders will actually read as a lean signal on the O2, telling me that a lot of unburned oxygen is being read.
dr_frankenstein
Mad Scientist
- Joined
- Mar 17, 2008
What does it take to assemble a waste spark system?
can it be used on a non EFI engine?
It seems like it has inherit advantages over the mechanical means that are currenty available. I also like the idea of whooping ass using largly factory engineered parts.
A.j.
can it be used on a non EFI engine?
It seems like it has inherit advantages over the mechanical means that are currenty available. I also like the idea of whooping ass using largly factory engineered parts.
A.j.
Yes. I wonder if we have been looking at "fake" egt numbers all these years.
A person i know dropped almost 200 deg off of his egts after going to a dist.
The XDI by Electromotive is a stand alone digital ignition system. It was designed for those that do not need fuel control. People running carbs, mechanical injection, etc.
The XDI system is as potent as the ignition system that comes included with the Electromotive TEC (Total Engine Control) units. In fact, the TEC units were built around the XDI technology.
