Megasquirt to Link questions.

[434josh]

Currently running a Megasquirt MS3PRO and considering ditching it for a Link Thunder.

I have downloaded the PC Link software and played around with it..have come to the conclusion that it's definitely going to take some getting used to as compared to Tuner Studio it's a lot more cumbersome but still at the same time seems fairly simple. 

First question that comes to mind is wiring differences. I am running full sequential 8 cyl with a 36-1 crank wheel/hall sensor and single tooth cam sync/vr. The hall sensor on the crank is wired for 12v power and has a 2.4k pull-up resistor as required by the Megasquirt. Will that wire the same with the Thunder or will I need to remove the pull-up and select pull-up on the trigger in PC Link?

I hope I can just cut my harness just inside the firewall and wire into the 400mm A/B Link harness and be basics good to go. 

Are the ve tables basically the same? I have a near perfect table now, can I basically copy it over to PC Link and expect it to work/be reasonably close?

Thanks for any info that can be offered!

[Adamw]

6 hours ago, 434josh said:

First question that comes to mind is wiring differences. I am running full sequential 8 cyl with a 36-1 crank wheel/hall sensor and single tooth cam sync/vr. The hall sensor on the crank is wired for 12v power and has a 2.4k pull-up resistor as required by the Megasquirt. Will that wire the same with the Thunder or will I need to remove the pull-up and select pull-up on the trigger in PC Link?

A hardwired external pull-up will be fine, you can turn off the internal one in the software.  Or if you want to simplify your wiring you can remove the external one and turn on the internal one.  Either option will work fine - just as a general rule, the more external connections you have (especially if there are soldered) the more potential points of failure you have in the future, so something to consider.

 

6 hours ago, 434josh said:

Are the ve tables basically the same? I have a near perfect table now, can I basically copy it over to PC Link and expect it to work/be reasonably close?

I would say it will only be ball-park.  The MS only has a very basic fuel model that doesnt account for fuel properties etc so there will certainly be some differences, I would still expect the general shape will remain though so a lot of it will probably just need a general scale up or down.

[434josh]

Thanks Adamw.

The more I play with the PC Link sw the more I like it. 

One other question- the stepper idle valve outputs- how rugged are they? Are they known to fail often or are there tricks to keeping them alive? Yes there is a story behind this question. 

My MS3PRO has cooked the iac drivers twice now. Amp efi has fixed it without question but this last time it only lasted for 50 miles. It worked great while it worked. First time it lasted about 300 miles. 

This makes 3 times it's been back for repairs in 350 miles so you can understand my utter frustration.

The stepper IAC valve is just a 4 wire delco gm valve, nothing special. Nothing the ecu should have trouble with.

[Simon]

The drives are good for 2Amps and are protected so generally don't fail. The most common fail we see is due to reverse voltage.

The GM stepper will be fine however there are some stepper motors out there that are very low resistance and we have seen then burn out. (Test case was a Lotus Elise) 

[Davidv]

On 5/13/2018 at 1:31 PM, 434josh said:

  have downloaded the PC Link software and played around with it..have come to the conclusion that it's definitely going to take some getting used to as compared to Tuner Studio it's a lot more cumbersome but still at the same time seems fairly simple.

Hahahaha no trust me, once you're used to it you'll not want to go back. It's a lot better than tuner studio.

And as mentioned the fuel equation in megasquirt is very simplistic by comparison.

And just take a browse through the help file, possibly the best help file I have ever seen for any product.

I will say this though - I still use Megalog viewer sometimes because PClink doesnt currently support custom/maths channels which is a pity. It's the only reason I stray outside of the Link system though, and only occasionally.

[Woody]

434josh , you are now on a journey of discovery , which will highlight how good Link is ,ditching MS will be the best thing you can do ..

 

Good luck with your swap .

 

cheers keith

[434josh]

I hope so Keith! Thanks for the good wishes. 

I have made a basic map/setup in the link software bit there is one thing I haven't figured out if it's possible to do.

I run a meth injection setup that's fully controlled by my megasquirt. It turns a pump on at a certain tps (with a relay) and pwm's a fast valve that draws 4.75 amps at 105 kpa. Using a high current out directly. I can't seem to figure out if the link will allow for a switched ve and timing table when the meth valve is being actuated. I am also seeing the outputs are limited to 2a max. Are there any that can handle 5a? I guess I can install a ssr on the fast valve but I was hoping to not need to. 

[Adamw]

For the valve current I think an SSR would be the best option, the Auxes will do more than 2A for a considerable period before getting too hot but I think 4.75A is pushing the boundaries a bit far.  The injector outputs can do 10A, but you dont have as much control flexibility with those for PWM and you will be already using all 8 for seq injection.

For switching tables there are many options.  If you wanted to completely switch to a fully independent table then you would turn on the "Dual fuel/ignition table" (under fuel corrections), set it to dual table mode and assign its activation to the aux that is driving your pump or you can switch it with a virtual aux if you want to add further activation conditions.  It will then switch to table 2 when the pump is activated.  If you dont need the resolution of a completely separate fuel table, then another option is the 4D/5D overlay style tables.  You can simplify these a little more - like for instance you might just want add 5deg timing to the whole ignition map above 4000RPM whenever the meth inj is activated...

[434josh]

Is there a way in the link software to alter the tables to show map kpa with 100 kps being atmospheric pressure? It's default set to zero = atmospheric. 

[Adamw]

Yes, in your screenshot above the axis is set to MGP (Manifold Gauge Pressure), change it to MAP for absolute.  Right-click then select axis set up, you can also change the breakpoints to whatever you like and add or remove rows/columns while there. 

 

[434josh]

Well I feel dumb. That was easy. Awesome.

[434josh]

Guys I really appreciate the help. The Megasquirt is now gone. New owner picked it up earlier today. 

Now I have to decide on a Thunder or Extreme. 

With the extreme I will use all 10 outputs. 

4 for IAC, 2 for my meth injecton setup, 2 for staged fuel pumps, one for fan and last one for my Mac 4 port boost valve. 

I would have no outputs left for any future expansion which worries me but I don't know what else I would expand to right now other than maybe a bump box. I could also eliminate one of the meth outputs by running a switch to activate the pump and a digital input activating the fast valve and that would give me one unused output. 

Is it an issue to use all of the outputs? I wouldn't think so but have to ask. 

The extra outs and direct lambda/egt control would be awesome but I am not sure if it's $500+ awesome plus 4 harnesses vs 2. 

Last question - I would like to make my own harnesses and I have found what I believe to be the right plugs but is there any info about terminal spacing or other data? I live right down the road from Mosuer and they have them in stock. 

[Adamw]

Another option would be to wire the coils in wasted spark pairs which will give you another 4 aux outputs.  No real difference in terms of ignition power doing this but it would mean you couldnt do individual cylinder ignition trims - including individual cyl knock retard. Another option if you had the need for more outputs in future would be to adopt a solenoid type idle valve.  They only need a single output, are faster to respond and dont need all the extra "hold power" wiring.

A connector 4-1437290-0

B connector 4-1437290-1

For the terminals just search "superseal 1.0", you can get them in a variety of plating types (suggest Au) and wire sizes.