Intake Manifold Design | Horsepower Calculators .net
Damn Good Article
Monday, December 27, 2010
Thursday, December 23, 2010
Exhaust Gas Analysis
CO2 - Carbon dioxide: This is the relative efficiency of the burn from complete combustion of the fuel. At all engine speeds, the best power will generally be found within less than a 0.3% change.
O2 - Oxygen: If the percentage is high, it indicates that more ignition advance can likely be used, or that the different cylinder offsets/staggers need correction due to a lean condition in one cylinder.
CO - Carbon monoxide: Mixture strength from partially burned fuel. If a given throttle position makes best power at a given percentage. All other throttle positions will be very close to this reading at best power.
HC - Total hydrocarbons in parts per million: Unburned fuel - Shows general state of engine health with lower readings for good large bore engines, and higher readings for good small bore engines.
NOx - Nitrogen Oxides in parts per million: High readings indicate high combustion temperatures and can be a precursor to detonation. Among many things, this hydrocarbon count indicates compression and squish/quench conditions, as well as spark strength and combustion dynamics
O2 - Oxygen: If the percentage is high, it indicates that more ignition advance can likely be used, or that the different cylinder offsets/staggers need correction due to a lean condition in one cylinder.
CO - Carbon monoxide: Mixture strength from partially burned fuel. If a given throttle position makes best power at a given percentage. All other throttle positions will be very close to this reading at best power.
HC - Total hydrocarbons in parts per million: Unburned fuel - Shows general state of engine health with lower readings for good large bore engines, and higher readings for good small bore engines.
NOx - Nitrogen Oxides in parts per million: High readings indicate high combustion temperatures and can be a precursor to detonation. Among many things, this hydrocarbon count indicates compression and squish/quench conditions, as well as spark strength and combustion dynamics
Exhaust Gas Analysis - Ignition Timing
I see this more often than I want. Mosty when a customer comes in with the latest and greates cams that are poorly matched to their engine combination. More is not better. More cam duration requires more static compression, or dynamic compression drops. A less efficient and lazy engine is the result. Even if peak power increases, the engine takes longer to rev to the same engine speed, resulting in a slower combination.
Choose to keep the cam(s) and increase compression, or change cam(s). Higher octane fuel doesn't help. You might try running a fuel with faster burn characteristics and working with cam timing as a band-aid fix to poor cam selection. But it is not the best answer.
O2 and CO2 levels will tell you a good bit about ignition advance - especially when more is needed or the fuel is way off. No specific numbers, as each engine combination and mapping alter combustion efficiency. But the ratio of both gases can indicate a lot until you get a good grasp on a particular engine combination.
THC goes up with poor combustion, as does carbon particulates (soot).
Fuels with too slow burn rate for needs, as well as poor vaporization, atomization and homoginization, will all require richer fuel mixtures - increasing CO% required for best output. But you can go too far with all of these as well. Great BSFC and response, but limited output due to fuel vapor displacing air.
NOx will provide a lot of info on ignition advance limitations and knock limits prior to the onset of detonation in knock-limited combinations.
I have putting together more information on gas analysis over the past few months, but it will take a few months to get back to it. We are in the middle of moving into a new facility. I will post up when it is complete.
_________________
"To achieve anything in this game you must be prepared to dabble in the boundary of disaster." -Sterling Moss
Choose to keep the cam(s) and increase compression, or change cam(s). Higher octane fuel doesn't help. You might try running a fuel with faster burn characteristics and working with cam timing as a band-aid fix to poor cam selection. But it is not the best answer.
O2 and CO2 levels will tell you a good bit about ignition advance - especially when more is needed or the fuel is way off. No specific numbers, as each engine combination and mapping alter combustion efficiency. But the ratio of both gases can indicate a lot until you get a good grasp on a particular engine combination.
THC goes up with poor combustion, as does carbon particulates (soot).
Fuels with too slow burn rate for needs, as well as poor vaporization, atomization and homoginization, will all require richer fuel mixtures - increasing CO% required for best output. But you can go too far with all of these as well. Great BSFC and response, but limited output due to fuel vapor displacing air.
NOx will provide a lot of info on ignition advance limitations and knock limits prior to the onset of detonation in knock-limited combinations.
I have putting together more information on gas analysis over the past few months, but it will take a few months to get back to it. We are in the middle of moving into a new facility. I will post up when it is complete.
_________________
"To achieve anything in this game you must be prepared to dabble in the boundary of disaster." -Sterling Moss
Wednesday, December 22, 2010
Friday, December 17, 2010
Saturday, December 11, 2010
Heatd O2 4 wire
Wires on 4 wire O2:
WHITE: Signal Wire
GREEN: Signal Ground
2 BLACK: Both black wires are the heater circuit wires.
Using a P28 ECU (and should work for most obd1 ecu's with 4-wire controls)
Run O2 Sensor signal (white) To D14
Run O2 Sensor signal Ground (green) to D22 (or any good Ground)
Run O2 Sensor Heater Circuit Control (black) to A6
Run the other black heater circuit power wire to (A25) or any good switched +12VDC source.
WHITE: Signal Wire
GREEN: Signal Ground
2 BLACK: Both black wires are the heater circuit wires.
Using a P28 ECU (and should work for most obd1 ecu's with 4-wire controls)
Run O2 Sensor signal (white) To D14
Run O2 Sensor signal Ground (green) to D22 (or any good Ground)
Run O2 Sensor Heater Circuit Control (black) to A6
Run the other black heater circuit power wire to (A25) or any good switched +12VDC source.
Thursday, December 9, 2010
Hondata - Return to Idle (9th December 2010)
Problem is really solved now. Here what I did
Not as easy as "no name" after market ECU, but learned alot!
My return to idle on throttle lift off at 4,000 rpm, clutch in is now ALWAYS a glide path back to target idle - 1,300 rpm
- Tune the idle air-con on and air-con off to the same afr using O2 (sensor overlay worked best) . Used a richer mixture (race cams, exhaust reversion) - O2 swing/STRIM didn't look so good at richer mixtures, but engine likes it. This made a big difference
- Checked the ECU was bumping up INJ and IGN, the instant ACSW=0
- Fined Tuned the IGN in the idle air-con off and idle air-con, and the trace area between to the two areas, such that the IGN always goes up (e.g. from 30 deg air-con off to 33 degrees air-con. This made a big difference
- Dumped fuel in 12kPa load area 1800 rpm to 3,000 rpm
- Set over-run TPS (MAP) to 8KpA 500rpm to 4000rpm - i.e minimum setting as possible
- Quicken STRIM rate of change
Not as easy as "no name" after market ECU, but learned alot!
My return to idle on throttle lift off at 4,000 rpm, clutch in is now ALWAYS a glide path back to target idle - 1,300 rpm
Monday, December 6, 2010
IACV Unplugged = Closed (Set Base Idle)
If you want to test the IAC valve to make sure it will fully close down, you can temporarily unplug it. When you unplug the IAC valve the idle should drop to the base idle. When the car is fully warmed up, and is on base idle, all the air is being controlled on the idle bypass screw. If the idle air bypass screw does not seem to have total control over the idle, the IAC valve may not be shutting down completely, or there is another source of unmetered air.
Saturday, December 4, 2010
Friday, December 3, 2010
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