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Megasquirt ve table transformation
omega 24 v6 - 30/11/08 at 12:24 PM

Well now that the car is running not to bad I'm trying to work out how to transform the whole table in one go. I had a base generated table with a reqd fuel of 11.0

After tuning an idle some of the figures are really low at idle in the ve table. This makes sense as the motor is really rich and sooty.
Also if you try to rev it then there is black smoke and it stumbles and farts and pops etc.

I need to change the reqd fuel to around 8.5 which will bring the table entries to around 30 at idle BUT it also ups all the other as yet untuned entries to an even richer amount. I reckon the original reqd fuel table of 11.0 needs scaling down by 60 percent. However if i go back into the table generator and put in the figures it generates a table with all my rpm/tps bins altered.?? I've attached my current steady idle msq for perusal and comment. In particular my tps bins are from 55 to 250 but when the table is regenerated the scale is from 55 to100. I realize that it's percent adc but when on the car and the throttle is operated it's at 100% long before the end of the actual throttle movement. Also in the tuning section of the extra efi site the tps scale shows 31 to 215 scale as an example.
What is everyone else on a vauxhall XE using as required fuel?? I realize it depends on bodies and injectors mines are gsxr750 and the 750 injectors.

[Edited on 30/11/08 by omega 24 v6]

omega0684 - 30/11/08 at 01:33 PM

im not running vauxhall engine im running pinto on R1 TB's and i have a problem that the car continually runs rich at about 12-13:1 at idle, i have managed to get the car to idle at about 1000rpm but my fuel req values are 18 & 9 (in top and botom boxes) when the car is at running temperature my tps values on my ve table span from 30 - 225 and at idle the values are between 18-20. im trying to get the car to idle around 14:1 but i just cant do it! if i alter the values so that it runs leaner the idle rpm goes up to about 1500rpm.

omega 24 v6 - 30/11/08 at 01:41 PM

quote:

when the car is at running temperature my tps values on my ve table span from 30 - 225 and at idle the values are between 18-20. im trying to get the car to idle around 14:1 but i just cant do it! if i alter the values so that it runs leaner the idle rpm goes up to about 1500rpm.

The extra efi site reckons at idle the ve entries should be around 30 also the highest entry on a N/A engine should be around 150.
They also quote not to try and get 14.7 at idle but rather to have a steady idle at the lowest MAP reading possible.
It could be ( and it's a consideration I'm having myself) that the throttle bodies are able to flow so much air that a lower idle speed may not be possible or practical to achieve. This is due to the fact that even a minute throttle open of a couple of thou would allow a large quantity of air into the engine tus uping the idle speed considerably. IMHO of course

paulf - 30/11/08 at 01:45 PM

You need to readjust the idle screw after weakening the mixture, if there is no adjustment left then you may have an air leak somewhere.
This is the reason I am running speed density and using the vacuum rather than throttle position as I think it is easier to adjust correctly as long as you can get a reasonable vacuum signal resolution.
Paul.

quote:
Originally posted by omega0684
if i alter the values so that it runs leaner the idle rpm goes up to about 1500rpm.

paulf - 30/11/08 at 01:54 PM

I wouldnt use the base table generator as if I understand you correctly you are using the megatune one which was for a V8. I would just find a map for the same engine and alter the fuel figures to suit your injectors. This wont be correct but will give a starting point closer than the megatune map generator.
I wouldnt worry to much about what the figures are at the idle end of the map, it could be 30 or 10 as long as it idles well.
If you know your injector flow rate accurately then that figure should give the correct spread across the map.When you start scaling it ive found it easier to get errors.
Paul.

omega 24 v6 - 30/11/08 at 02:09 PM

quote:

If you know your injector flow rate accurately then that figure should give the correct spread across the map.When you start scaling it ive found it easier to get errors.


Not quite sure what you mean. I have a v2.2 board and currently am tuning the idle. It's fine now but before I go back and setup the cold start etc I'd like to be sure that after I start running and tuning the car on the road that I will not have to alter the whole map by say 15 to 20 points at each bin. I'd rather work out where I'm at just now and gloabally alter the ve table so that i'm only altering each bin by a smaller amount (or megalog viewer is altering it ). The way I see it just now I will not be able to accelorate the car due to the fact it's gonna flood itself or bog down horrendously due to the higher ve settings in the next rev/tps range.

Edited to add that my original calcs with the reqd fuel calculator came up with a reqd fuel of 13.9. I rescaled to 11 and still think i need to come lower again.

[Edited on 30/11/08 by omega 24 v6]

omega0684 - 30/11/08 at 04:14 PM

omega 24 v6: im just wondering what flow rate are you using for your throttle bodies, i've put in 220 cc/minute. is this anything like what you have?

omega 24 v6 - 30/11/08 at 04:52 PM

I presume you mean inj flow rate
I have 230cc/min

martyn_16v - 30/11/08 at 10:54 PM

quote:
Originally posted by omega 24 v6
Well now that the car is running not to bad I'm trying to work out how to transform the whole table in one go.


Assuming you're using megatune, open up the VE table dialog, and go to Tools -> VE Specific -> Reset ReqFuel

omega 24 v6 - 1/12/08 at 06:17 PM

quote:

Assuming you're using megatune, open up the VE table dialog, and go to Tools -> VE Specific -> Reset ReqFuel


Yep I know how to do that Martin. But surely it'll change all my settings at idle (already mapped part) as well.