TPS/potentiometer??

Throttle position set, 0% 710 mv and 100 % 3670 mv. After setting TPS, this is the advance map that TCIP4-program gave automatically. I tested the settings with idle and engine sounded ok. I haven't been on the road yet, so no practical experiences with proper driving?
tps1.jpg

So you clever people, any idea where to go next (with advance map)?
 
Way out my comfort zone here but at 5 and 10% throttle opening (is that what the y-axis shows?) the settings seem to give way too much advance (assuming the numbers shown are degrees advance).
If not I have no clue.
 
Not sure of the validity of a TPS on a carburettored engine, your advance map, in the main, should be plotted against RPM not throttle position. The TPS input in a conventional engine management system uses both throttle position and throttle position rate of change signals to alter injector timing i.e. fuel mixture. Any ignition retard will normally be triggered by a knock sensor or an over RPM signal. For sure small gains may be made throught the rev range by adjusting ignition timing against engine load but how you would accurately map that using a set of Dellortos that splutter fuel everywhere, are not temperature compensated and with no provision for measuring inlet manifold depression or exhaust gas analysis I've no idea, I would say you got a bit of experimentation in front of you. Good luck !


    Keith.
 
the process is sound

part throttle cruise usually allows the engine to run more advance
than what would be normal for full throttle or engine load conditions

the 5% and 10% advance numbers from 4000 up look a bit much in the first table
in the second that appears to have been rectified
i see a conservative map bump beginning at 2000, looks like a better starting point


as keith points out the real world validity needs some thinking

if the ignition is set up for optimal timing under different throttle positions
it has no way to account for major changes in air density
without changing the map

EFI can by changing fuel delivery in concert with a finer ignition map
but it also relies on additional sensors for calculations

maybe you can set up a baro or MAP sensor as a separate input to address this
there are two switchable inputs. perhaps they could be used as limits for the sensors
eg; air too dense switch to a default map, air too lean switch to a default map

if your curve is set near the mechanical limits
(by the time you hear detonation it is too late ... and that's with a silent exhaust)
at prevailing weather conditions
think about what happens when the air density drops from heat or rain
or increases from a dry cold front

how will you find the mechanical limits, without destruction, to best use the
capabilities of the adjustable map?


i'm also inclined to think you need a way to correlate throttle openings to engine speeds through the gears

 
jotacorsa said:
think about what happens when the air density drops from heat or rain
Click to expand...

I'm impressed Scott. 99% of people think the air gets "heavier" when it's humid. But you're absolutely correct - it gets less dense. It also has less oxygen available for combustion (some of the O2 molecules are displaced by H20).
Heat doesn't necessarily decrease air density. It's more often associated with an increase in atmospheric pressure rather than an increase in volume.
The predominant factor in air density variations is altitude.

I dunno how the ignition timing should respond to reduced air density. Retard or advance?

Cheers,
Cam
 
There are stand - alone det sensors available which can retard within 2 - 3 revolutions.
might be an idea to splice one in....air cooled motors are not an exact science.
 
G'day Mark

I agree entirely. Heat is very significant. An internal combustion is a heat engine, so it's efficiency is directly related to the incoming air temperature. The cooler the better.
The nit-picking and somewhat useless point I was making is that a change in ambient temperature does not in itself mean a change in air density.

BTW, we get hot weather here. Sometimes it gets up to 20oC  :o

Cheers,
Cam
 
Dellortoman said:
, is that a change in ambient temperature does not in itself mean a change in air density.
Click to expand...

well , my kool Antarctic mate ,,  why does Miss J seeem to pull harder at the top of the range !!  she luvs it, mate!
i always thought it was the cool air?  maybe me bum dyno (seat of pants) is way out of whack, eh?
, and on a very hot dry day, she will try and detonate her head off !!
i agree with ya humid thinking , a bit of water vapour doesn't take up much room in air.
cheers,  Tropo Marko
 
markQLD said:
well , my kool Antarctic mate ,,  why does Miss J seeem to pull harder at the top of the range !!  she luvs it, mate!
i always thought it was the cool air?  
Click to expand...

G'day you troppo bastard  :D

I think we're actually saying the same thing in different ways.

It probably is the cool mountain air making your engine run sweeter.

Here's a technical explanation (there could be others): The maximum theoretical thermal efficiency of a heat engine = 1 - Tc/Th
With Tc (cold) being the temperature at the start of the combustion cycle and Th (hot) being the temperature at the end of the cycle.

You can see that reducing Tc will increase efficiency, The only way for efficiency to increase with the same amount of fuel going in is for the power output to increase.
Of course, there's a limit to the altitude that a combustion engine will operate, which is why you'll never get to the moon in a piston engine (or jet) aircraft. If you get high enough you'll eventually run out of air.

You might also have ignition timing a wee bit too advanced, so it runs well with cool air but struggles when it's hot. Try switicing to a curve with less advance when it's hot.

Cheers,
Cam

 
My understanding of  cold air is that yes it is denser, but that it contains more oxygen

Running a little leaner?? not much but enough to notice

RamAir Chaps


TPS on Carbys

Please tell me the point
 
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