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Megasquirt on a V8 build


v8GTmac1

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On 23/12/2019 at 22:00, snowrx said:

Personally, I'd avoid the complexity of staging secondaries. Just get the primaries the pulse width they need, or go to bigger injectors if you exceed your duty cycle (or fuel pressure) availability. Two additional injectors would seem like they would never give you truly equal fuel distribution to all the cylinders, unless they only come on with enough WFO airflow and heat to completely vaporize the fuel before the runners separate.

guess what, I made this new video and if you notice i'm reving a little higher then my last vid. I'm now going lean instead of rich at the higher end. 

Problem was the factory ECU was turning on the 2nd fuel pump mid way thru the REV range, upping the pressure so high it pegged my AFR to the rich side all the sudden. And the Lotus manual states the secondary fuel pump and injectors are for high speed only 🤨  130+ mph my arse. 

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On 25/11/2019 at 19:26, snowrx said:

+1 for the MS3X board, it just makes adding features easier.

Oh and I recieved this in the mail yesterday. THis will be so much fun. Full sequential on everything, idle control and boost along with water injection. i'll be able to optionally run the secondary pump and injectors progressively.

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12 hours ago, v8GTmac1 said:

Problem was the factory ECU was turning on the 2nd fuel pump mid way thru the REV range, upping the pressure so high it pegged my AFR to the rich side all the sudden. And the Lotus manual states the secondary fuel pump and injectors are for high speed only 🤨  130+ mph my arse. 

Perhaps adding an aftermarket fuel regulator with more capacity to keep pressures steady in spite of the second pump?  Or just use a one pump system with a higher capacity pump? I don't know the intent of a two pump system, unless they thought the primary was undersized. "Hydraulic" high load enrichment would seem a little vague to implement.

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  • Gold FFM
On 10/01/2020 at 15:45, v8GTmac1 said:

8 LEDs to the 12v pulsed leg of each of the 8 ignitors 

run the engine at the lowest rpm and record them flashing with camera in slomotion to capture their firing order. 

Then you know which is for what cylinder and have an attack plan. Is any of this clear enough to understand? Or do I need to tackle this job and post a vid ?

 

Hi Michael,

I'd love to know the answer regarding all 8 ignitors, how soon can you post the video? 😄

This thread is fascinating. Keep up the good work everyone. 👍

cheers

-Chris

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5 hours ago, snowrx said:

Perhaps adding an aftermarket fuel regulator with more capacity to keep pressures steady in spite of the second pump?  Or just use a one pump system with a higher capacity pump? I don't know the intent of a two pump system, unless they thought the primary was undersized. "Hydraulic" high load enrichment would seem a little vague to implement.

Yes Aeromotive is the one who makes an adjustable FPR for the Chevy fuel system we use.

  Bigger injectors then I already invested in is another thought.

Bigger single fuel pump as well and Leave the secondary in place if the 1st leaves me stranded. 

 

Im thinking the reason for the complexity was to have smoother control of smaller injectors rather then larger when at low duty cycle (idle) which in return nets better mpg. 

And perhaps the entire system is capable of 500hp as we all know the 918 can produce any day of the week and twice only Sunday.....

At this point without continued investment into experimentation, I will most likely mimic the oem setup and run it all progressively. 

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  • 5 weeks later...

It's been running for a few weeks on Full Sequential MS3x and I couldnt be happier to drive her in this awsome weather. 

It is on 4.5psi wastegate pressure with no Duty going to the boost solenoid. 

23 degrees of timing at those boost levels but i have no idea what it should be. 

The factory ECU is currently only doing the job of working the SPeedo gauge which reads 5 MPH High. 

Currently the AC needs to be re-wired due to the oem ecu not getting a CAM signal thus no longer getting RPM readings. 

Oh and at 4.5psi the 252cc Mustang injectors have allready Max'd out the higher you go into the REVs. 

I have the secondaries and the 2nd F/P hooked up for staged injection but needs more seat time with the laptop to tune it's progressive nature, it gets really rich!

https://www.youtube.com/watch?v=K6M4RZW7gpg

 

Edited by v8GTmac1
Here is a good video.
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Nice work. It should be super easy to get the wheel speed and A/C hooked up to the MS. For speed, you just need to change the sensor type at the rear wheel and run one extra wire (standard is VR sensor and MS needs hall effect). You can then remove the stock ECU completely.

Another benefit of having the speed go through the MS is that you can also fill out the gearing info. That way, the ECU can work out what gear you are in by comparing speed and RPM. Opens up opportunities for things like boost vs gear etc.

Edited by cammmy
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5 hours ago, cammmy said:

Nice work. It should be super easy to get the wheel speed and A/C hooked up to the MS. For speed, you just need to change the sensor type at the rear wheel and run one extra wire (standard is VR sensor and MS needs hall effect). You can then remove the stock ECU completely.

Another benefit of having the speed go through the MS is that you can also fill out the gearing info. That way, the ECU can work out what gear you are in by comparing speed and RPM. Opens up opportunities for things like boost vs gear etc.

I like boost Vs gear. 

Although being that the speedo is a universal VDO gauge, 

it can be calibrated directly to the VSS

or I can order a VDO GPS module. 

Atm I will leave as is but I do need to ad a relay to turn compressor on and off. 

I have a output ready for turning off the AC when programmed to. 

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Quick n' Dirty Hall effect VSS install for Megasquirt-

I just epoxied 6 neodymium magnets to the periphery of the CV joint (don't use JB weld, it's got ferrous bits in it, and will get messy as it mounds up around the magnets!) and stuck a mount under the carrier fixing bolt. Generic 12V eBay hall sensor, I don't recall the specs, works fine.

 

VSS (2).JPG

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  • 2 months later...
On 12/02/2020 at 19:26, snowrx said:

Quick n' Dirty Hall effect VSS install for Megasquirt-

I just epoxied 6 neodymium magnets to the periphery of the CV joint (don't use JB weld, it's got ferrous bits in it, and will get messy as it mounds up around the magnets!) and stuck a mount under the carrier fixing bolt. Generic 12V eBay hall sensor, I don't recall the specs, works fine.

 

VSS (2).JPG

I like your style and I might have to try that 

rather then tapping into the existing VSS and hindering signals going to the ABS. 

 

 

 

 

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Update for Apr

AC connection with megasquirt was a simple 2 wire connection. 

12v request from the AC pressure switch  +                                                      Compressor relay (ground) actuation

both if these taken off the ECU connector. 

 

2nd fuel pump was not being turned on for whatever reason  I fixed that and now I’m able to put the secondary injectors and pump starting at 4psi

FYI oem ecu triggers the 2nd pump practically all the time under low boost.    So if you have yours disabled !!!!! Fix that!!!

 

https://youtu.be/k_lqbtUusMw

Edited by v8GTmac1
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12 hours ago, v8GTmac1 said:

I like your style and I might have to try that 

rather then tapping into the existing VSS and hindering signals going to the ABS. 

 

 

 

 

On my GT3, the ABS and VSS sensors were totally separate. I just removed the VSS sensor and replaced it with a hall type that had the correct thread. It involved running one extra wire along with the existing two.

 

It didn't have any effect on the ABS.

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For others to be happy they would more then likely require PnP style connection. Have not spent any time looking for a bare ecu connector. And the factory ecu is still controlling the Speedo on mine. 

Ive mentioned before the VDO speedo is universal and VDO sells a GPS converter box. 

But yes once my fuel tables are set up to 11psi then I will be more then happy to post my tune and settings. 

Been a lot of fun finding wires. Finding the ACU relay box took me some hours lol

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  • 1 month later...
  • 7 months later...
On 10/01/2021 at 15:20, snowrx said:

Does the speedo agree with VSS on your datalog?

Actually. Ever since my oem ECU, whose sole purpose was to pulse the feed the speedometer stopped working. My speedo now runs off the speed sensor directly.  

Because of this I need to build a VR to Hall effect circuit that MS can interpret. In the meantime I am used “MFactory  gear ratio calculator”

with tire size, gear ratios and rpm to figure out my exact speed. 

May speedo is reading around 5mph higher because I’m too lazy to recalibrate it. 

Turned up the boost to 10 psi

but lowered my timing advance from 18-16*

 

what's crazy is that at this level I am only using the Primary pump and running good DUty Cycle on the injectors. 

lotus-log.jpg

Edited by v8GTmac1
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  • 1 month later...
  • Gold FFM

Hi @v8GTmac1,

I may have asked this before but not sure I've seen an answer (I may not have been paying attention, sorry).

At the moment my car is a huge collection of bits in preparation for rebuilding with nice new and refurb'd shiny stuff.

While it is apart I am wondering what modifications, additions etc I should be sorting out to give me the option of running your ECU and code (should it become an option, I don't want to be too presumptuous)?

Is it possible to have the car built with all the necessary bits to be able to swap between the two ECUs quite simply or is it an either or situation for some of them? 

It would be great if I could prep this in readiness while I am building it up to save revisiting bits later. 🙂 

You've done an amazing job and your reward might just be people like me becoming a PITAs while trying to adopt your great work. 😇

cheers

-Chris

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The only way to make it swappable is if you leave all of the wiring intact and also make an adapter to fit the harness to the MS. I tried to do this with the plugs from a broken ECU but it just wasn't practical. Doing this would also mean you can't run a wideband O2 sensor, which is one of the main reasons for going aftermarket.

I would highly recommend totally ditching the factory ECU and wiring in a full standalone. If you get the right impedance injectors, the only wiring to be done is changing the wheel speed sensor (need one extra wire running), changing to a wideband O2 sensor(I used a Spartan 2) and adding a pull up resistor to the Speedo. The MS3/X can do everything you need and them some. It's worth a little extra effort up front to fully remove the factory ECU as it actually simplifies things and reduces points of failure. If he shared his map with you, that should still all work, you just need to make sure your additional settings are all correct.

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absolutely guys, it's a dream of mine to have others venture away from the stock ECU CHip upgrade limitations. glad that Cammy chimed in, I think it was CAmmy that kept pushing me to go MS3x full sequential. BUt i did successfully run MS2 semi-sequential with all the stock sensors and coils BUT the oem ecu didnt want to share ckp/cam sensors so I was getting RPM spike issues.

Although I dont know where you could ever find a broken ECU to permanently borrow the male side of the connector in order to make a PNP build. Other options are to open the stock ecu and re-route the necessary terminals out thru a grommet and into a megasquirt, this option looks clean when you want to let the Lotus ECU work the speedo & AC. But MS can do all that except the speedo. I found a solution for it though.

I am more then happy to post my MS tunes here for you guys with screen shots of the important bits.  

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Posted (edited)
On 15/03/2021 at 08:10, cweeden said:

Hi @v8GTmac1,

 

While it is apart I am wondering what modifications, additions etc I should be sorting out to give me the option of running your ECU and code (should it become an option, I don't want to be too presumptuous)?

 

-Chris

If I was to do it again which I will, while the engine is out I would do all the wiring going everywhere it needs to go like gauges, fuel pump relay. My current state is a wiring nightmare to most but oh boy does she run great! 155mph so far. 

Remember to shop for replacement primary injectors, mine are from a 2000 Mustang Cobra. with MS3x you can run all 10 injectors no problem with the secondaries being LOW impedance. 

But I have to say that I did go away from the OEM ckp sensor and mounted a 36-1 wheel on the harmonic balancer, fabricated a bracket to hold a VR crank sensor and I am still using the CAM sensor for full sequential but thats only because I also got rid of the OEM coilpacks. 

here is my initial success story https://www.msextra.com/forums/viewtopic.php?f=104&t=72257

and btw, if I cant help from overseas, there are 10x better MS gurus in different parts of UK that can be of service. 

Edited by v8GTmac1
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