Tunning and HIGH lambda readings

[Agriv8]

Made a few more logs will check them errors.

Goal's not sure what you mean.

regards

agriv8

[Agriv8]

rob been thinking about this question most of the weekend.

and all I could come up with ( feel like its an exam )

Goals, get the car to :-

1) ticking over beter than stock ECU
2) accelerating better than stock ECU
3) get the best out of an engine designed before I was born.
4) to run without the dizzie

So I answers to 1 and 2 already sorted assisted by 4

3) I know 3 is going to take a rolling road session ( somthing that I am going to have to save up for) but as I can know see what the engine is doing ( lambda ) and adjust  the fueling to get it as good as I can until I can afford the rolling road and enjoy some of the good weather we are having.

4) even if my spark table spark table is not the best it is likley to be better than the dizzie , bob weights and vacumes ( so the 80's )

So possibly answering the question.

With what I have available aiming to get the lambda as close to 1 across all driving and idle
so in reality wihout the rolling road suspect the clossest I am going to get between .95 and 1.05.

reasoble goal do you think ?

regards agriv8

[rob@vems.co.uk]

1) Well thats often taken for granted and the effort involved is underestimated.  Gary@APT got a lovely smooth idle on Kev's engine using two cells 200rpm either side of the target idle speed.  It worth looking at doing something like that yourself.

2) This will come through getting the right fuel and ignition maps along with the right acceleration enrichments (Tip-ins), you'll find that this improves as the mapping improves.

3) Thats your perogative, personally Id go for a japanese multi-valve engine over an old Buick truck engine

4) Have you looked at any of the spark advance curves that the old bob weights used to give, are there any around?  If so you'll at worst be able to mimic them with a higher level of accuracy and steadyness than the sloppy dizzy could ever give.  Either way you should be able to start with a "known good" ignition map.

Driving around on your own using datalogs to record the lambda against MAP (or TPS if your on AlphaN) and RPM will allow you to get close to 1.0, but slowly.  Quicker still would be to have someone drive, holding the engine at a steady state slowly building RPM so that you can map live.

The key bit is to experiment, log everything and keep saving your tables - dont be afraid to put your maps to one side and try something radically different.

Now you have the transient voltage diode in your flyback you'll find that your VE table (if you're using Speed Density) will become really quite flat.

Try a bit of AlphaN tuning see how you get on with that.

Read Jorgen's Tuning sessions:
http://www.vems.hu/wiki/index.php?page=TuningSession%2FClosedloopTuning
http://www.vems.hu/wiki/index.php?page=TuningSession%2FOpenloopTuning

[dnb]

1)  Certainly possible.  I found the Rover stepper could be set up well with the PID controller, and along with ignition advance idle control and careful mapping  - I had a map row at 500 RPM (that occasionally gets used when Nic drives the car!!) and at 1000.  This was good enough with a sensible ignition map to get a very stable idle.  The transient diode helps with this too!

2)  Couldn't agree more with Rob.  It seems the Rv8 responds well to accurate fuelling and quite a bit of timing advance.  You can also get good economy!

3)  Some of us like the old Buick truck engine.    I remember when Rob first drove the Griff...  He wasn't quite expecting it to be like it was.

4)  I have the timing profile for the TVR bob weights.    They're far from ideal as the dizzy was very compromised to stop det at higher RPM.  You can do much better even if you are conservative.  Rovers seem to like lots of timing at part throttle.   (I think I sent you my timing map in my MSQ file.  It was based on the dizzy weights - it's the conservative version but it should give you some clues)

I favour a lambda of 1 for idle (emissions) but lean it off to around 1.05 for low MAP value cruising.  I aim for 0.86 on acceleration (ie high MAP values in the map) and use the tip in (acceleration enrich) to remove the lag inherent from the way speed-density works.  I found that I had to add quite a lot of fuel for acceleration, but then 5 litres isn't exactly a small engine.  You can get lambda VERY accurate without a rolling road.  It's only timing you can't do easily on the road.  (I was lucky enough to be working north of London at the end of last year - I got LOTS of tuning done )

[Agriv8]

Thanks Chaps, Just what I wanted to hear.

dnb running your spark map and its lot happier on that - than the 'evil Dizzie'.

Still not running a Stepper as have a feeling it would only add another ? into the equation ( I can get confused easy enough ). My feeling is Ill add one if needed to assist with tickover.

Rob

mapping on the fly didnt think of that

 Wanted V8 test pilot ( must have a steady right foot ) size 13 feet and 38 inside leg 

Seriously I have a couple of mates ( who I trust ) who could be the wheel man.

Regarding the V8 yup it does not make sense especially in a 750 kilo car but it floats my boat 

Many thanks for all the help you have given me a few 'areas to look at' 

Agriv8

[dnb]

I'm pleased my spark map is OK for you  

On the fly mapping is great.  Nic got very good at holding the car in a load cell in the end.

[cliffb75]

The key bit is to experiment, log everything and keep saving your tables - dont be afraid to put your maps to one side and try something radically different.

That is one of the best bits of advice that anyone can give. Record keeping is absolutely critical. But if you are meticulous about it you can try radical changes, safe in the knowledge you can always step back to a known 'good' state.

I favour a lambda of 1 for idle (emissions) but lean it off to around 1.05 for low MAP value cruising.  I aim for 0.86 on acceleration (ie high MAP values in the map) and use the tip in (acceleration enrich) to remove the lag inherent from the way speed-density works.  I found that I had to add quite a lot of fuel for acceleration, but then 5 litres isn't exactly a small engine.  You can get lambda VERY accurate without a rolling road.  It's only timing you can't do easily on the road.

That's about right. For catalyst cars that only need to pass MOT or SVA emissions I'd consider setting the idle and low load line up to 3000rpm at a target lambda 1.02 (reduces HC and CO emissions, which is what they test for). You can get fuelling right through just driving about, but ONLY if you take logs of all your drives. This applies for start and warmup compensations too. You will find however that you change you driving style to hold the car in different load 'steps' (i.e. engine accelerates along a constant load line in the table).

[rob@vems.co.uk]

mapping on the fly didnt think of that

Wanted V8 test pilot ( must have a steady right foot ) size 13 feet and 38 inside leg 

Seriously I have a couple of mates ( who I trust ) who could be the wheel man.

Regarding the V8 yup it does not make sense especially in a 750 kilo car but it floats my boat 

Many thanks for all the help you have given me a few 'areas to look at' 

Yep, you need a man (or woman) who is not a fool when in the car, who'll be more interested in helping than acting the prat.  Once you have that you're part of the way there... Long slow sweeps up the rev range with varying levels of urgency!

But you wont need a wheel man to get your idle creamy smooth, just some time.  And some experiments - for example make a map up thats almost completely concentrated in the idle area RPM: 500, 600, 700, 800, 900, 1000, 1100, 1500, 2000, 4000, 5000, 6000.  Kpa  25, 30, 35, 40, 45, 50, 55, 60, 70, 80, 90, 100.  Flatten the advance out to your idle value right across the table, and do the same with the VE that gives you close to lambda1 at tick over.  You'll have so much resolution to play with that you'll get a feel for whats needed.

When you reload your original map you'll be able to work out what range you're idle settings will be and will be able to configure the cells accordingly.

Nothing against V8s every boat should have one! Just not enough valves to excite me! I'm hoping that we'll be seeing a 'proper' V8 appearing in the Projects section soon

And yeah idle control, its exactly that - another ? in the equation that makes for misery and upset 'till you need it dont use it!
Start with it shut off and get the car to idle nicely when its up at its operating temperature, and accept that you're going to have to blip the throttle when cold to stop the thing from dieing.

Then once you have a nice stable idle then add complication.

[dnb]

Nothing against V8s every boat should have one! Just not enough valves to excite me!

We've got as many valves as your Datsun has...

What new v8?  One of those nice little ones with 5 valves per cylinder? 

[Agriv8]

But you wont need a wheel man to get your idle creamy smooth, just some time.  And some experiments - for example make a map up thats almost completely concentrated in the idle area RPM: 500, 600, 700, 800, 900, 1000, 1100, 1500, 2000, 4000, 5000, 6000.  Kpa  25, 30, 35, 40, 45, 50, 55, 60, 70, 80, 90, 100.  Flatten the advance out to your idle value right across the table, and do the same with the VE that gives you close to lambda1 at tick over.  You'll have so much resolution to play with that you'll get a feel for whats needed.

Rob reading between the lines her ( or making it up as I go along ) are you saying that I can configure VEMS to create a table with the reference points we think are important ( or to put it another way More detail )

So a table that look like 

RPM -->500, 600, 700, 800, 900, 1000, 1100, 1500, 2000, 4000, 5000, 6000 MAP   |   v  25,  30,  35,  40,  45,  50,  55,  60,  70,  80,  90,  100

are there Instuctions anywhere to create and upload the table ?
--- > Mental note to switch learn off

I can create this New 'Start point' from my existing table

RE the V8 Must be one of those VAG ones

[Agriv8]

Just had a look at one of the ve tables I had saved.

will have a play and possibly another How to coming up.

regards

Agriv8

[rob@vems.co.uk]

Its more of a case of giving yourself more detail for the area of the map that you're interested in configuring.
Then you will find that theres theres redundancy of information in some of the mapping points, so you can remove them and still have the smooth idle you like.