MSefi.com read only forum (Jan.15,2018)

Hey, everyone. I just picked up a DIY Megasquirt kit for my E30 BMW. I've been tuning for about two years now and I'm used to tuning Greddy, CROME, Hondata, and AEM EMS.

I figured I'd get Megasquirt because I didn't want to shell out over a grand for Haltech, Motec, Autronic, etc. and I'm always up for a challenge.

I've read the megamanual and after reading it, it shares a lot of similarities with other engine management systems. The only things I want to get squared away before I start tuning are when trying to generate a VE table it always says torque at maximum HP is higher than the peak torque value. My figures are 315hp at 6500 rpm and 270tq at 5900 rpm with redline at 7000rpm.

Do I enter the values as I stated above or do I set the torque and horespower to the 7000rpm redline instead of 6500rpm for horsepower and 5900 for torque? There's no clear answer in the megamanual, unless I have to dig to find one.

Also with every other engine management system I've used there's a selectable option to retard timing over 100kpa. I read that megasquirt doesn't have an algorithm for timing yet. I generally retard 1 degree of timing per pound of boost to start off with. Is this acceptable with megasquirt or do I have to take other steps?

Huh, that's weird. I just tried it again and it worked. Maybe I was overthinking and inputing wrong numbers or something. I just tried 300tq at 3000 rpm and 315hp at 5000rpm and it gave me the max higher than peak error.

I'm just confused because I'm used to small displacement four cylinders. Like a previous 1.6 liter Honda engine making 426hp at near redline of 8200rpm, but torque falls off around 330 near 6800. When I input that into the VE generator. I get an error.

So basically if your tq and hp plot are unrealistic it will give the error?

For example..



I dunno, this is probably really simple and it's the simple stuff I over analyze.


As for timing I get it now I think. The megamanual is just a really long read then I started reading about timing offsets and was looking at other people's maps and it shows like 6* of advance and they say "note there's a 12* offset" so it's really 18*? I'm not sure if I'm understanding that correctly but atleast 18* sounds reasonable where 6* is just pointless.

Torque can be calculated if HP and RPM are known. Vice-versa, HP can be calculated from RPM and torque. All the generator is doing is cross calculating those two to make sure torque is higher at peak torque than at peak HP, and HP is higher at peak HP than at peak torque.

http://www.dragtimes.com/horsepower-tor ... ersion.php

[quote]As for timing I get it now I think. The megamanual is just a really long read then I started reading about timing offsets and was looking at other people's maps and it shows like 6* of advance and they say "note there's a 12* offset" so it's really 18*? I'm not sure if I'm understanding that correctly but atleast 18* sounds reasonable where 6* is just pointless.Omniscient [/quote]

With the "trigger offset" setings in Megasquirt, if everything is set correctly, the displayed timing will be actual. Sometines for tuning purposes I will generate a conservative table, and then use the trim angle to add timing to the whole map.

SQLGUY wrote:Torque can be calculated if HP and RPM are known. Vice-versa, HP can be calculated from RPM and torque. All the generator is doing is cross calculating those two to make sure torque is higher at peak torque than at peak HP, and HP is higher at peak HP than at peak torque.

http://www.dragtimes.com/horsepower-tor ... ersion.php

I've always just used hp = torque * rpm / 5252.

h22 wrote:

As for timing I get it now I think. The megamanual is just a really long read then I started reading about timing offsets and was looking at other people's maps and it shows like 6* of advance and they say "note there's a 12* offset" so it's really 18*? I'm not sure if I'm understanding that correctly but atleast 18* sounds reasonable where 6* is just pointless.Omniscient

With the "trigger offset" setings in Megasquirt, if everything is set correctly, the displayed timing will be actual. Sometines for tuning purposes I will generate a conservative table, and then use the trim angle to add timing to the whole map.

Ok, I think I get it now. But as for having to create my own timing map, is there an easier way to pull 1* per pound of boost than doing it cell by cell?

Omniscient wrote: Ok, I think I get it now. But as for having to create my own timing map, is there an easier way to pull 1* per pound of boost than doing it cell by cell?

You can select multiple cells and uncrease/decrease them all at once.