ignition timing at WOT question

[Belgian1979]

I've used parts of Clint's equipment (the combustion pressure sensors and logging) and it worked really good once I got the hang of it. It's ridiculously easy to build the perfect timing curve in a few tests on the dyno. However, Implementing and characterizing knock sensors is not as easy as it would seem. I'm sure Yves can find the best timing and fuel mix using the standard practices hotrodders have used for years . If he wanted/needed to make changes to ignition timing based on RPM, MAP, coolant temp, inlet air temp, or just about anything else - he can do it pretty easily now. This is reward of seeing a first-time EFI project to completion.

As for knock sensors : a lot of factors play a role here. Since I drained the engine of coolant, I also moved the sensor to the pan rail where the oem sensor usually is. No flickering of the knock light anymore. Might need to set it more sensitive now. The knocksense manual says to give it some low octane gas and induce knock. I'm really reluctant to try that.

[140Air]

nitro2

"or......... the perfect curve could be dialed in, in 3 engine tests, even without a dyno, using our equipment."

Can you educate me on your equipment?

Our combustion pressure analyzers do the regular things like record cylinder pressure and/or port pressures relative to crank angle, determine IMEP, IHP, IT, VE per cylinder per combustion cycle, energy release and energy release rates per combustion cycle etc. etc. etc.

However, not so commonly found, and relative to my statement above, our equipment will automatically go through every combustion cycle of every instrumented cylinder and determine how much sooner or later (in degrees) that the entire combustion process should have occurred, in order to have made the most uumph (IMEP, IT, IHP) for each and every combustion cycle. The software then automatically plots how far off of optimal the combustion process is located (in degrees) vs. rpm. The end user uses that knowledge to program in the relevant changes in ignition timing, so that the combustion process will be optimal for all rpm blocks for the very next test. If the programming changes were done correctly timing will be perfect for all rpm blocks on the second test, if not then one more iteration (test) will do the trick.

Obviously if after that some other kinds of significant mods are made to the engine, it might change things enough that the combustion process location has to be re-adjusted again, but that only takes another 1 or 2 more tests.

This is a dream system. How much does it cost to instrument and test each cylinder? Belgian didn't actually say he had efi, but for old school engines with carbs each cylinder is virtually unique.

[MadBill]

... but for old school engines with carbs each cylinder is virtually unique.

For sure! Reported in David Vizard's upcoming Big Block Chevy book Vol. II -which I was privileged to preview- with nitro2's help and equipment they gained power at every RPM point (max of 30 HP) Vs. a similar sized set of good equal length 4-1 headers, just by tweaking the individual tubes to very unequal lengths to match the individual cylinder's needs..

[Sweet P]

I ordered Vizards book, to be delivered in the beginning of the year, it was the first oppurtunity I seen to buy it.

[jmarkaudio]

... but for old school engines with carbs each cylinder is virtually unique.

For sure! Reported in David Vizard's upcoming Big Block Chevy book Vol. II -which I was privileged to preview- with nitro2's help and equipment they gained power at every RPM point (max of 30 HP) Vs. a similar sized set of good equal length 4-1 headers, just by tweaking the individual tubes to very unequal lengths to match the individual cylinder's needs..

I have to wonder if they are trying to affect distribution with different tube lengths? If that's the case then you might be better served with a better intake or building the carb to provide better atomization. I've seen on a Dyno with 8-O2's when atomization is improved distribution get better, and power follows.

[900HP]

This is a question related to EFI, but with some comparison to the conventional distributors used on SBC gen I's.

Let's assume WOT. Usually a SBC is given 36° or around that as maximum advance coming in at around 2800-3000 rpm. It stays there in a conventional distributor because the weights are maxed out.
In an EFI system it is possible to put less spark in at higher rpm, like 33 or 34 or so. Would this be benificial because the mixture is more homogenous and due to the higher compression pressures the burn rate is supposed to be faster or would it be better to have it stay at the 36°.

I currently have 36° from 2800 rpm onwards to max rpm. I was thinking of bringing this down somewhat to say 33° at above 4000 rpm. However my engine is a large bore short stroke, long rod combo which would play a part as well.

Here is a video that Dieselgeek made last year. There are a lot of things going on but you can watch our actual ignition advance in the upper left. We arrived at this after a lot of dyno pulls. Clint's equipment would make this easier and more accurate, however this curve made the best power for us.
http://www.youtube.com/watch?v=6kQGp-fH ... tube_gdata

[MadBill]

...I have to wonder if they are trying to affect distribution with different tube lengths? If that's the case then you might be better served with a better intake or building the carb to provide better atomization. I've seen on a Dyno with 8-O2's when atomization is improved distribution get better, and power follows.

I believe they were just trying to get the negative exhaust return pulses timed right, coping with the varying firing intervals, tube 'clocking' in the collectors, etc. Would have been nice to see A-B cylinder-by-cylinder AFRs though...

[140Air]

Here is a video that Dieselgeek made last year. There are a lot of things going on but you can watch our actual ignition advance in the upper left. We arrived at this after a lot of dyno pulls. Clint's equipment would make this easier and more accurate, however this curve made the best power for us.
http://www.youtube.com/watch?v=6kQGp-fH ... tube_gdata

What engine is that? Also, how is AFR measured, EGTs?

[nitro2]

nitro2

"or......... the perfect curve could be dialed in, in 3 engine tests, even without a dyno, using our equipment."

Can you educate me on your equipment?

Our combustion pressure analyzers do the regular things like record cylinder pressure and/or port pressures relative to crank angle, determine IMEP, IHP, IT, VE per cylinder per combustion cycle, energy release and energy release rates per combustion cycle etc. etc. etc.

However, not so commonly found, and relative to my statement above, our equipment will automatically go through every combustion cycle of every instrumented cylinder and determine how much sooner or later (in degrees) that the entire combustion process should have occurred, in order to have made the most uumph (IMEP, IT, IHP) for each and every combustion cycle. The software then automatically plots how far off of optimal the combustion process is located (in degrees) vs. rpm. The end user uses that knowledge to program in the relevant changes in ignition timing, so that the combustion process will be optimal for all rpm blocks for the very next test. If the programming changes were done correctly timing will be perfect for all rpm blocks on the second test, if not then one more iteration (test) will do the trick.

Obviously if after that some other kinds of significant mods are made to the engine, it might change things enough that the combustion process location has to be re-adjusted again, but that only takes another 1 or 2 more tests.

This is a dream system. How much does it cost to instrument and test each cylinder? Belgian didn't actually say he had efi, but for old school engines with carbs each cylinder is virtually unique.

Most customers spend $5k to $9k for a turnkey system. It'll do a whole lot more than tune your combustion timing LOL. Factoring in that it is easily transferable, i.e. tune your ATV one day, your dragster the next, your hotrod the next, the guy's hotrod down the road the next, the cost per use spread out over say 10 years of use is actually pretty minimal, for those in a position to put it to good use. At the other end of the spectrum some customers will instrument just one engine, typically a high level engine or tight class type engine and do R&D on the engine indefinitely so as to stay at least one step ahead of the competition on an ongoing basis.

IMO within the spectrum of companies and serious tuners, there really is no logical argument for not knowing what is going on inside the cylinder and the ports of an engine in real time, while the technology to do so is readily available. A hobbyist is a bit of a different scenario, but even some hobbyists are pretty serious about what they are doing and get involved with real time measurement of what's going on in the cylinder and ports.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TFX Engine Technology Inc.
Engine Pressure Instrumentation (Combustion/Intake/Exhaust)
http://www.tfxengine.com

[900HP]

Here is a video that Dieselgeek made last year. There are a lot of things going on but you can watch our actual ignition advance in the upper left. We arrived at this after a lot of dyno pulls. Clint's equipment would make this easier and more accurate, however this curve made the best power for us.
http://www.youtube.com/watch?v=6kQGp-fH ... tube_gdata

What engine is that? Also, how is AFR measured, EGTs?

Engine Master's 428 Pontiac, wideband in each tube.

[900HP]

Most customers spend $5k to $9k for a turnkey system. It'll do a whole lot more than tune your combustion timing LOL. Factoring in that it is easily transferable, i.e. tune your ATV one day, your dragster the next, your hotrod the next, the guy's hotrod down the road the next, the cost per use spread out over say 10 years of use is actually pretty minimal, for those in a position to put it to good use. At the other end of the spectrum some customers will instrument just one engine, typically a high level engine or tight class type engine and do R&D on the engine indefinitely so as to stay at least one step ahead of the competition on an ongoing basis.

IMO within the spectrum of companies and serious tuners, there really is no logical argument for not knowing what is going on inside the cylinder and the ports of an engine in real time, while the technology to do so is readily available. A hobbyist is a bit of a different scenario, but even some hobbyists are pretty serious about what they are doing and get involved with real time measurement of what's going on in the cylinder and ports.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TFX Engine Technology Inc.
Engine Pressure Instrumentation (Combustion/Intake/Exhaust)
http://www.tfxengine.com

^^^what he said^^^ I had the opportunity to see the TFX equipment and what it can do. I will own my own one of these days.

[jmarkaudio]

Our combustion pressure analyzers do the regular things like record cylinder pressure and/or port pressures relative to crank angle, determine IMEP, IHP, IT, VE per cylinder per combustion cycle, energy release and energy release rates per combustion cycle etc. etc. etc.

However, not so commonly found, and relative to my statement above, our equipment will automatically go through every combustion cycle of every instrumented cylinder and determine how much sooner or later (in degrees) that the entire combustion process should have occurred, in order to have made the most uumph (IMEP, IT, IHP) for each and every combustion cycle. The software then automatically plots how far off of optimal the combustion process is located (in degrees) vs. rpm. The end user uses that knowledge to program in the relevant changes in ignition timing, so that the combustion process will be optimal for all rpm blocks for the very next test. If the programming changes were done correctly timing will be perfect for all rpm blocks on the second test, if not then one more iteration (test) will do the trick.

Obviously if after that some other kinds of significant mods are made to the engine, it might change things enough that the combustion process location has to be re-adjusted again, but that only takes another 1 or 2 more tests.
Most customers spend $5k to $9k for a turnkey system. It'll do a whole lot more than tune your combustion timing LOL. Factoring in that it is easily transferable, i.e. tune your ATV one day, your dragster the next, your hotrod the next, the guy's hotrod down the road the next, the cost per use spread out over say 10 years of use is actually pretty minimal, for those in a position to put it to good use. At the other end of the spectrum some customers will instrument just one engine, typically a high level engine or tight class type engine and do R&D on the engine indefinitely so as to stay at least one step ahead of the competition on an ongoing basis.

IMO within the spectrum of companies and serious tuners, there really is no logical argument for not knowing what is going on inside the cylinder and the ports of an engine in real time, while the technology to do so is readily available. A hobbyist is a bit of a different scenario, but even some hobbyists are pretty serious about what they are doing and get involved with real time measurement of what's going on in the cylinder and ports.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TFX Engine Technology Inc.
Engine Pressure Instrumentation (Combustion/Intake/Exhaust)
http://www.tfxengine.com

Are these for a single cylinder or all 8 at once?

[nitro2]

You can instrument as little or as much as you want, anywhere from 1 high speed pressure sensor to 28 of them. In my experience its best to go with as capable an analyzer as you might need plus a few sensors, then add more sensors (if need be) as you gain familiarity with what you are doing. This accomplishes 2 things: 1) spreads out the cost over time and 2) stops one from getting in over their head at the start with too much info.

[Belgian1979]

Maybe you could give a group deduction when sufficient people would decide to buy.

[Flo]

from own experience I can only tell you, that 5k to 9k is a STEAL for a system like that.....

The Kistler system we used for 8 cylidners was around 20k € for a 4 banger if I remember correctly. That was without the conditioning system for the sensor coolant.

Besides the actual data acquisition system the sensors themselves are really pricy.