My Megasquirt recipe for Alfa Nord 4-cylinder - Alfa Romeo Bulletin Board & Forums
 9Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 32 (permalink) Old 03-29-2017, 10:54 PM Thread Starter
Registered User
 
jarrington's Avatar
 
Join Date: Apr 2005
Location: Denver, CO
Posts: 2,169
My Megasquirt recipe for Alfa Nord 4-cylinder

After much trial and error I managed to get my Megasquirt Spider project running for the first time today. Since nearly everything I've seen on Megasquirt for Alfas is tailored to either the V6 or Twinspark crowd I've tried to document what I've learned for posterity including specific part numbers for everything I had to source to make it happen. This build was based on a Bosch vintage Alfa engine including intake manifold and plenum.

The file is a 3.7MB PDF with plenty of pictures. I'll add more detail as I get further into tuning, etc. but since the car is now running I think I can call the basic approach a success.
Attached Images
File Type: pdf NordMicrosquirt_V1.pdf (3.67 MB, 691 views)
simon johnson, IanB and abeasley like this.

Jason Arrington
1989 Spider driver
1974 Spider restoration project
jarrington is offline  
Sponsored Links
Advertisement
 
post #2 of 32 (permalink) Old 03-30-2017, 06:41 AM
Senior Member
Platinum Subscriber
 
alfaparticle's Avatar
 
Join Date: Oct 2004
Location: Columbia SC
Posts: 12,675
Congratulations on finishing the install and thanks for the excellent documentation. There are many days when I wish that my Spider has Megasquirt.

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
alfaparticle is offline  
post #3 of 32 (permalink) Old 03-30-2017, 10:17 PM Thread Starter
Registered User
 
jarrington's Avatar
 
Join Date: Apr 2005
Location: Denver, CO
Posts: 2,169
Thanks Ed. I was a bit surprised that there wasn't more info out there on doing Megasquirt on Alfa engines. I guess my thinking was that having an easily repeatable pattern for cheap EFI on a Nord it would give another option besides spending $1k or more on a Weber swap or a rebuilt SPICA. The superior performance, economy, and emissions of programmable EFI is of course a big bonus.
GioGTVTS likes this.

Jason Arrington
1989 Spider driver
1974 Spider restoration project
jarrington is offline  
Sponsored Links
Advertisement
 
post #4 of 32 (permalink) Old 03-31-2017, 09:09 AM
Registered User
 
Join Date: Mar 2007
Location: San Antonio, Texas
Posts: 4,063
I wish you hadn't done this. I'd obsessed over a Megasquirt several years ago until I finally convinced myself that I like the original tactile responses of a Weber equipped Alfa. While I still like the way a Weber equipped Alfa sounds and drives, you've got me thinking about installing a Megasuirt again . . . dammit.
horsewidower likes this.

Jim . . . '72 Super 1300, '70, 1750GTV, 2nd series,
'62, Lancia Flaminia Zagato3c, 2nd series
180OUT is offline  
post #5 of 32 (permalink) Old 03-31-2017, 09:46 AM
Senior Member
Platinum Subscriber
 
alfaparticle's Avatar
 
Join Date: Oct 2004
Location: Columbia SC
Posts: 12,675
I have a hot 2L motor with 45 Webers and a hot 3L motor with Megasquirt and I tune both of them. It is not difficult to get the Webers good at WOT, high RPM but the midrange just lands where it is. You have some control with emulsion tubes and alternative main jet/Air corrector combinations but it will never be better than a good compromise. There are 100 bins in the Megasquirt fuel table that are either filled individually based on AFR observation, etc or adjusted automatically when you turn on the auto-tune.

My 3L motor is set up to produce an AFR of 13.2 +/- 0.2 all the way from 3500 to 7000 rpm but I was getting lousy gas mileage - about 14 mpg average. Just recently I set up the AFR table with 13.2 at all high VE, 14.7 in much of the remainder and 15.5 in the cruising condition - 50% - 70% VE and 2500 to 4000 rpm. Now the mpg appears to be in the mid 20's - better than my Spider in a heavier car with about 60 more HP.

My next project is to install a PWM idle air valve to replace the sorry L-Jet device.
horsewidower likes this.

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
alfaparticle is offline  
post #6 of 32 (permalink) Old 03-31-2017, 11:52 AM
Registered User
 
Join Date: Apr 2010
Location: New Jersey
Posts: 104
Great write-up! It is very generous of you to go to all the trouble of documenting everything so others can benefit. You should post a link to this thread in the Spider section.

I would love to follow your lead and it is great that you did fuel and spark. However, it is a little outside my comfort zone, so it will have to stay on the wish list.
Jim99 is offline  
post #7 of 32 (permalink) Old 03-31-2017, 01:20 PM
Registered User
 
Join Date: Mar 2007
Location: San Antonio, Texas
Posts: 4,063
Slowly, slowly, I turn, resisting the impluse until . . . . You know what would be really cool? We could get a pair of the Jenvy throttle bodies that are made to look just like DCOE Webers, except they're not, they're really fuel injection throttle bodies. Then we could use an oem Weber manifold and carb linkage along with stock airbox and a plenum. We could have a Megasquirt ECU managed engine that retained it's classic Portello era 105 Alfa underhood appearance! Ugh, I think I need a aspirin.

Jim . . . '72 Super 1300, '70, 1750GTV, 2nd series,
'62, Lancia Flaminia Zagato3c, 2nd series
180OUT is offline  
post #8 of 32 (permalink) Old 03-31-2017, 01:46 PM
Senior Member
Gold Subscriber
 
horsewidower's Avatar
 
Join Date: Jun 2006
Location: Wilton Ca
Posts: 2,295
I'm still fiddling with adapting the SPICA ITBs to electronic FI. I like a stealth look.


Sent from my iPhone using Tapatalk

Everyday is a school day. Learning something new all the time

View my '74 GTV restoration at:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


View my '91 164s adventure at:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


But wait there's more: View my 164LS thread:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


You're kidding, another one?! 1984 GTV6 Maratona
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


You didn't...oh yes I did. '73 Berlina graduate course in rust repair. No thread yet, don't want to piss off the GTV

You didn't...oh yes I did II. 1995 164LS 5 speed, awesome when it runs!!!

Musings on shop related items:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
horsewidower is online now  
post #9 of 32 (permalink) Old 03-31-2017, 02:18 PM
Registered User
 
Join Date: Mar 2007
Location: San Antonio, Texas
Posts: 4,063
Stealth:

http://www.jenvey.co.uk/products2/tw...-40-48mm-tdsxx

Jim . . . '72 Super 1300, '70, 1750GTV, 2nd series,
'62, Lancia Flaminia Zagato3c, 2nd series

Last edited by 180OUT; 03-31-2017 at 02:25 PM.
180OUT is offline  
post #10 of 32 (permalink) Old 04-02-2017, 04:34 PM Thread Starter
Registered User
 
jarrington's Avatar
 
Join Date: Apr 2005
Location: Denver, CO
Posts: 2,169
I thought about the Jenvey TBs. Ultimately decided that when there's a perfectly viable factory intake manifold and plenum available for peanuts it's kind of hard to justify the cost of the TBs. And of course then you'd need to come up with a custom throttle linkage and fuel rail.

Jason Arrington
1989 Spider driver
1974 Spider restoration project
jarrington is offline  
post #11 of 32 (permalink) Old 04-02-2017, 09:29 PM
Registered User
 
Join Date: Mar 2007
Location: San Antonio, Texas
Posts: 4,063
Actually you don't the Jenvey throttle bodies, regular and DCOE style, use standard Alfa Weber linkage. Although they look cool, they are pretty expensive, however.

Jim . . . '72 Super 1300, '70, 1750GTV, 2nd series,
'62, Lancia Flaminia Zagato3c, 2nd series
180OUT is offline  
post #12 of 32 (permalink) Old 04-03-2017, 05:48 AM
Senior Member
Platinum Subscriber
 
alfaparticle's Avatar
 
Join Date: Oct 2004
Location: Columbia SC
Posts: 12,675
Jason's set up is simpler than ITB's because he can get a good MAP signal from the plenum. With ITB's you will need to get a composite signal from the four or use throttle position instead of MAP.

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
alfaparticle is offline  
post #13 of 32 (permalink) Old 04-03-2017, 08:31 AM Thread Starter
Registered User
 
jarrington's Avatar
 
Join Date: Apr 2005
Location: Denver, CO
Posts: 2,169
Quote:
Originally Posted by alfaparticle View Post
Jason's set up is simpler than ITB's because he can get a good MAP signal from the plenum. With ITB's you will need to get a composite signal from the four or use throttle position instead of MAP.
Can you use just a TPS for Megasquirt? I thought the recommendation was TPS plus MAP, MAF, or both.

Jason Arrington
1989 Spider driver
1974 Spider restoration project
jarrington is offline  
post #14 of 32 (permalink) Old 04-03-2017, 10:36 AM
Senior Member
Platinum Subscriber
 
alfaparticle's Avatar
 
Join Date: Oct 2004
Location: Columbia SC
Posts: 12,675
Quote:
Can you use just a TPS for Megasquirt?
I am pretty sure that Al Mitchell has implemented one. It is like electronic SPICA with much more user control.

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
alfaparticle is offline  
post #15 of 32 (permalink) Old 04-03-2017, 01:16 PM
Registered User
 
GV27's Avatar
 
Join Date: Dec 2004
Location: Lakewood, Colorado
Posts: 1,719
Garage
Send a message via AIM to GV27
Well done, Jason, and thanks for the write-up!

Chris

1990 Spider Veloce
GV27 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Alfa Romeo Bulletin Board & Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome