I get bored easily. - Page 5 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 01-31-2012, 03:55 AM   #81
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

If the gate driver ground pin is gonna be separated from the MOSFET Source pin by 2 long ground wires that go to the engine block, the MOSFET gate resistor better be increased to more like 1 kohm. And it has to physically sit close to the MOSFET with short trace to the gate pin. If not you might have yourself a very energetic 20 MHz oscillator and the magic smoke might come out.

On the datasheet of the IXDI414, and "clean analog ground" is relative to its VCC. It doesn't care if it sits on a ground plane that is bouncing around relative to the engine block. What matters then is the noise it sees on its input, and how tight the connection to its MOSFET is.

And that's why I would use a 74C14.
JasonC SBB is offline   Reply With Quote
Old 01-31-2012, 11:00 AM   #82
Elite Member
iTrader: (10)
 
Join Date: Oct 2008
Location: Seattle, Wa
Posts: 1,780
Total Cats: 30
Default

Quote:
Originally Posted by Joe Perez View Post
I edited my post #76 above before I saw that you'd posted a reply.

Everything seems clean on the bench, so I'm going to try it as-is.

(Besides, it's all together and I'm feeling lazy.)

I present the Hellasquirt:



Jeff_Ciesielski is offline   Reply With Quote
Old 02-02-2012, 01:25 PM   #83
Hear me Meow
iTrader: (3)
 
skidude's Avatar
 
Join Date: Apr 2008
Location: Outside Portland Maine
Posts: 1,994
Total Cats: 13
Default

Very impressive. Makes me feel inadequate with my run-of-the-mill MS3/x.
skidude is offline   Reply With Quote
Old 02-13-2012, 09:55 AM   #84
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,328
Total Cats: 1,926
Default

It lives!

Attached Thumbnails
I get bored easily.-7sbq0.jpg  
Joe Perez is online now   Reply With Quote
Old 02-13-2012, 09:58 AM   #85
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

nice! congrats joe.
Braineack is offline   Reply With Quote
Old 02-13-2012, 10:42 AM   #86
Elite Member
iTrader: (11)
 
Join Date: Jun 2007
Location: Overland Park, Kansas
Posts: 5,382
Total Cats: 43
Default

Holy crap. That's far beyond awesome...
elesjuan is offline   Reply With Quote
Old 02-13-2012, 10:58 AM   #87
I'm a terrible person
iTrader: (19)
 
FRT_Fun's Avatar
 
Join Date: Apr 2009
Location: Arizona
Posts: 7,293
Total Cats: 180
Default

This thread kind of makes me want to have Joe's babies.
FRT_Fun is offline   Reply With Quote
Old 02-13-2012, 11:15 AM   #88
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

does joe have a say in the matter?
Braineack is offline   Reply With Quote
Old 02-13-2012, 11:26 AM   #89
I'm a terrible person
iTrader: (19)
 
FRT_Fun's Avatar
 
Join Date: Apr 2009
Location: Arizona
Posts: 7,293
Total Cats: 180
Default

Only if he says yes.
FRT_Fun is offline   Reply With Quote
Old 02-15-2012, 05:27 AM   #90
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,328
Total Cats: 1,926
Default

For what it's worth, I've seen a lot of people ask "can I tune with a narrowband sensor", and I'm officially changing my answer from "Well, probably, but it'd be sub-optimal" to "you'd have to be an idiot to try."

With a fresh ECU and an untuned VE table, trying to use a narrowband sensor to get things whipped into shape is like trying to un-bend a connecting rod using a PowerCard.

Fortunately, I still have my old AEM UEGO lying around which I pulled out of the red car in disgust and replaced with an LC-1 several years ago. It's not the most accurate thing on the planet, but it's "good enough" to get the VE table roughed in. I had actually planned on this possible contingency when building the Hellasquirt, and brought out an additional analog input from the CPU's AD6, so that I can connect the NB02 sensor to it as a calibration reference for the wideband. I also split the wiring in the harness to allow swapping this wire with the O2 wire, and additionally brought out power, ground, and the aux analog input on a separate 3-pin Molex connector at the harness.

So, long story short, with the AEM connected to O2 and the narrowband connected to AD6, I can see that the AEM is, as usual, reading about 0.5AFR lean at stoich, and have corrected the AFR table to accommodate this. With that done, it's running well enough to get the VE table sort of roughed-in by hand and then let TunerStudio do its magic.

In keeping with the low-budget theme of this build, behold my ghetto-fabulous gauge mounting solution:



(Yes, that's a Fedex box.)


The ultimate goal is to return to a narrowband sensor once the VE table is more or less beaten into shape.
Attached Thumbnails
I get bored easily.-vtn5r.jpg  
Joe Perez is online now   Reply With Quote
Old 02-15-2012, 01:26 PM   #91
Elite Member
iTrader: (5)
 
Join Date: Dec 2010
Location: Raleigh, NC
Posts: 1,970
Total Cats: 49
Default

just curious (and not sure if you covered this before), but why go back to the narrowband? just because of the budget theme?
Seefo is offline   Reply With Quote
Old 02-15-2012, 02:13 PM   #92
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,328
Total Cats: 1,926
Default

Quote:
Originally Posted by Track View Post
just curious (and not sure if you covered this before), but why go back to the narrowband? just because of the budget theme?
Well, a couple of reasons.

First, the narrowband gauge is inherently more accurate. This AEM unit I have is known to have some offset in the analog output, and I don't really trust its internal calibration to begin with. By comparison, I have a brand new 4-wire narrowband installed, and the "calibration" of narrowband sensors, by definition, is more or less inherently perfect. There is some temperature-related drift in the voltage, but regardless of the absolute "rail" voltages, it will always undergo a sharp swing in output right at the stoichiometric point.

As I need to pass CA emissions, accuracy of the O2 sensor at the stoichiometric point is critical.


Second, my ultimate goal for the car is to have a 100% stock appearance, which again goes back to the CA emissions thing. So that means only one O2 sensor installed in the downpipe. I should mention at this point that some previous owner, for reasons unknown, had a second O2 sensor bung welded into the downpipe. When I bought the car, there was an old 4-wire sensor still in the second hole, with the wires cut off. (I found no wiring in the car which corresponded to it, so this pipe may have come from a different car.) This was convenient for me as it allows me to run the wideband along with a narrowband reference sensor, but ultimately I will be removing the wideband and plugging the hole, thus returning to an apparently stock configuration.


Obviously this means I will be ultimately be running open-loop at the very top of the VE table, so I'll just use the wideband to get that part of the map dialed-in where I want it, and then lock it off and leave it alone.
Joe Perez is online now   Reply With Quote
Old 02-15-2012, 02:42 PM   #93
Hear me Meow
iTrader: (3)
 
skidude's Avatar
 
Join Date: Apr 2008
Location: Outside Portland Maine
Posts: 1,994
Total Cats: 13
Default

Quote:
Originally Posted by Joe Perez View Post
Well, a couple of reasons.

First, the narrowband gauge is inherently more accurate. This AEM unit I have is known to have some offset in the analog output, and I don't really trust its internal calibration to begin with. By comparison, I have a brand new 4-wire narrowband installed, and the "calibration" of narrowband sensors, by definition, is more or less inherently perfect. There is some temperature-related drift in the voltage, but regardless of the absolute "rail" voltages, it will always undergo a sharp swing in output right at the stoichiometric point.

As I need to pass CA emissions, accuracy of the O2 sensor at the stoichiometric point is critical.


Second, my ultimate goal for the car is to have a 100% stock appearance, which again goes back to the CA emissions thing. So that means only one O2 sensor installed in the downpipe. I should mention at this point that some previous owner, for reasons unknown, had a second O2 sensor bung welded into the downpipe. When I bought the car, there was an old 4-wire sensor still in the second hole, with the wires cut off. (I found no wiring in the car which corresponded to it, so this pipe may have come from a different car.) This was convenient for me as it allows me to run the wideband along with a narrowband reference sensor, but ultimately I will be removing the wideband and plugging the hole, thus returning to an apparently stock configuration.


Obviously this means I will be ultimately be running open-loop at the very top of the VE table, so I'll just use the wideband to get that part of the map dialed-in where I want it, and then lock it off and leave it alone.
This all sounds brilliant, but wouldn't the emissions people notice a turbo? Or do you take that all out for emissions testing?
skidude is offline   Reply With Quote
Old 02-15-2012, 02:57 PM   #94
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,328
Total Cats: 1,926
Default

Quote:
Originally Posted by skidude View Post
This all sounds brilliant, but wouldn't the emissions people notice a turbo? Or do you take that all out for emissions testing?
This is the blue car, the one I'm keeping (almost) entirely stock. No turbo.
Joe Perez is online now   Reply With Quote
Old 02-15-2012, 03:04 PM   #95
Elite Member
iTrader: (5)
 
Join Date: Dec 2010
Location: Raleigh, NC
Posts: 1,970
Total Cats: 49
Default

Interesting! What are the legal ramifications if they find out you are running a megasquirt?
Seefo is offline   Reply With Quote
Old 02-15-2012, 03:07 PM   #96
Hear me Meow
iTrader: (3)
 
skidude's Avatar
 
Join Date: Apr 2008
Location: Outside Portland Maine
Posts: 1,994
Total Cats: 13
Default

Quote:
Originally Posted by Joe Perez View Post
This is the blue car, the one I'm keeping (almost) entirely stock. No turbo.
Oh yeah, I forgot you have a second miata.
skidude is offline   Reply With Quote
Old 02-15-2012, 03:16 PM   #97
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,328
Total Cats: 1,926
Default

Quote:
Originally Posted by Track View Post
Interesting! What are the legal ramifications if they find out you are running a megasquirt?
Death by firing squad.

In all honesty, I'm not entirely certain. The law is extremely vague on this point, and I have heard of penalties ranging from fines to seizure and crushing. It's not my intention to find out for sure.

Having a pre OBD-II vehicle makes things slightly easier in this regard, since there's no plugin test to be done- only the visual and tailpipe inspection. The tailpipe test, in theory, should not be a problem, so I'm focusing on visual.

To that end, I'm trying to keep everything as stock-like in appearance as possible. This means no abnormal-looking wiring under the hood, no gauges on the interior, etc. I have even set the system up so that the Check Engine light comes on when you power up the car, and then goes off once RPM rises above 500.


Quote:
Originally Posted by skidude View Post
Oh yeah, I forgot you have a second miata.
Had.

I sold the red car late last year. Still not entirely sure what the next project is going to be.
Joe Perez is online now   Reply With Quote
Old 02-15-2012, 03:31 PM   #98
Senior Member
iTrader: (5)
 
Join Date: Jul 2011
Location: Sonora, Ca
Posts: 623
Total Cats: 73
Default

Have you seen the Honda turbo setups where they hide the manifold and turbo behind the stock exhaust heat shield and run the cold side piping through the factory air box and intake? When I'm not on my phone I'll look for it.
bikersam717 is offline   Reply With Quote
Old 02-15-2012, 03:35 PM   #99
Hear me Meow
iTrader: (3)
 
skidude's Avatar
 
Join Date: Apr 2008
Location: Outside Portland Maine
Posts: 1,994
Total Cats: 13
Default

That sounds... impressive.
skidude is offline   Reply With Quote
Old 02-15-2012, 03:46 PM   #100
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,328
Total Cats: 1,926
Default

Quote:
Originally Posted by bikersam717 View Post
Have you seen the Honda turbo setups where they hide the manifold and turbo behind the stock exhaust heat shield and run the cold side piping through the factory air box and intake?
No, I hadn't seen such a thing.

But no turbo for this car. It's a shortnose with poor compression numbers that I paid $800 for, and I genuinely do intend to keep this one stock just to have as the "normal" car.
Joe Perez is online now   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
elesjuan's mediocre 95 Miata adventure (google fiber edition) elesjuan Build Threads 8 02-16-2016 09:36 PM
Mazdaspeed 2.0L C-Spec ITB motor w/ accessories graexodus Miata parts for sale/trade 9 10-25-2015 04:34 PM
New supertech pistons /wiesco xx rings HHammerly Miata parts for sale/trade 5 10-17-2015 07:53 AM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
What happened to my Dynalite? midpack Suspension, Brakes, Drivetrain 18 09-22-2015 08:52 PM


Thread Tools

Posting Rules
You may not post new threads
You may not 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



All times are GMT -4. The time now is 01:54 PM.