Fab9 LS Coil Conversion Kit - Market Study - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Fab9 Tuning - Miata Performance Parts Fab9 Tuning specializes in bringing the highest performing Mazda Miata parts on the market today.

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 08-05-2014, 08:31 PM   #21
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

Quote:
Originally Posted by mx592 View Post
Sorry if this is a stupid question, but if they were wired for wasted spark, would I be able to run them with a LINK ecu on my '94? Or do I need the ability to adjust dwell curves?
I don't know what the dwell tables in your Link look like (I understand that they're hard coded in the firmware), but I do have extensive experience with LSx coils. They need more dwell than what a stock Miata ECU commands. I can only ASSUME that a Link (again, ASSUMING FM Miata Link, not something newer like a G3) runs dwell similar to a stock Miata ECU. Therefor, I would conclude that this would not be a good fit.

That being said, I wouldn't suggest going for the type of power that would blow out spark with a Miata Link. I admit I may be biased, but I've also replaced Miata Links and picked up tons of power and drivability.
Ben is offline   Reply With Quote
Old 08-06-2014, 12:30 PM   #22
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

LS coils require longer dwell than you can get with wasted spark at high RPM.
JasonC SBB is offline   Reply With Quote
Old 08-06-2014, 12:43 PM   #23
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,107
Total Cats: 518
Default

Are LS coils not good for wasted spark and stockish redline? I've never known this. I've always planned on upgrading from my Toyota COPs in the far far distant future.
curly is offline   Reply With Quote
Old 08-06-2014, 01:50 PM   #24
Senior Member
iTrader: (1)
 
Join Date: Jan 2011
Location: Chattanooga, Tn
Posts: 1,038
Total Cats: 157
Default

Quote:
Originally Posted by JasonC SBB View Post
LS coils require longer dwell than you can get with wasted spark at high RPM.
Someone doesn't Math very well do they?

With a 8500rpm red line in wasted spark each coil will fire 8500 times a min or 142 times a second. That's every 7 milliseconds. With a 1 millisecond discharge rate you still have 6 milliseconds left for dwell. General rule I have heard is that due to over dwell protection built into the D585 coil you shouldn't dwell them over 4.7 milliseconds. So I see 1.3 milliseconds left.

You could theoretically spin a motor 10,526 RPM with D585 coils in wasted spark. In reality, if you factor in their maximum 80% intermittent duty cycle....you would be more than fine...In the real world....With D585s, in wasted spark, up to 8500rpm.

Last edited by TNTUBA; 08-06-2014 at 02:48 PM.
TNTUBA is offline   Reply With Quote
Old 08-06-2014, 02:28 PM   #25
Junior Member
iTrader: (2)
 
Join Date: Nov 2010
Posts: 499
Total Cats: 48
Default

I'm ready for some lsx coils
BlackBandit is offline   Reply With Quote
Old 08-06-2014, 02:50 PM   #26
Junior Member
iTrader: (13)
 
Join Date: Jul 2007
Location: San Antonio, TX
Posts: 498
Total Cats: 6
Default

I'd be interested with just the bracket. I already have the LS truck coils. FYI...I don't have a coolant reroute if that matters.
lsc224 is offline   Reply With Quote
Old 08-07-2014, 06:02 PM   #27
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Quote:
Originally Posted by TNTUBA View Post
Someone doesn't Math very well do they?

With a 8500rpm red line in wasted spark each coil will fire 8500 times a min or 142 times a second. That's every 7 milliseconds. With a 1 millisecond discharge rate you still have 6 milliseconds left for dwell.
What you're missing is that *I* was the one that FM asked to measure dwell on some *actual* LS coils a few years back, and that the required dwell can go > 6 ms.

You will never win at math against me. I work in an engineering group and I'm often the go-to guy for sticky math problems. <evil laugh>
JasonC SBB is offline   Reply With Quote
Old 08-07-2014, 08:31 PM   #28
Senior Member
iTrader: (1)
 
Join Date: Jan 2011
Location: Chattanooga, Tn
Posts: 1,038
Total Cats: 157
Default

I have 3 degrees. One of which is in Mathematics. I used to tutor Engineering students. They were so cute thinking Matrix Algebra was hard.

There are only about 4 different variants of LS coils. The most powerful being the D585s which conversely require the least amount of dwell and are shown to become unstable and over saturated when dwelled longer than 5.5 ms. I run a set of D585s, in wasted spark, on a 11:1 motor with 25 PSI crammed on it and I spin it well beyond the factory reline. I dwell them according to the GM dwell table and run a very healthy spark gap. To say they "require" 6 ms of dwell is simply not accurate.
TNTUBA is offline   Reply With Quote
Old 08-07-2014, 08:56 PM   #29
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

You guys are both right.

I have seen D585 coils that will eat as much dwell as you can give them. I don't think I saved any scope traces, but the coils on my car loved 7 ms of dwell. I've seen others that would trigger themselves while being dwelled somewhere in the 5 or 6 ms range.

I'm sure there are multiple revisions and manufacturers of GM coils. Frankly a coil that fires itself while being dwelled and current limiting is FRAKING STUPID. Save the coil but possibly lose an engine? Engineering at its worst.

Also, there is an elephant in the room that has not been addressed. Dwell is a function of voltage. I want to say that my voltage at coil primary, measured by oscilloscope, was 14VDC. Honestly I set that about 5 years ago and haven't touched or looked at it since.
Ben is offline   Reply With Quote
Old 08-08-2014, 12:14 PM   #30
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Agreed on stupidity.
The popular Toyota COPs will fire themselves at 80 ms if V>10.5 and 330 ms if V<10.5.
They should have designed them to reduce the current to zero over a millisecond or so instead of firing.
I didn't see that same behavior on the LSx coils FM sent me for testing.

+1 on > 7 ms at low battery voltages for max secondary current, on said coils. Additionally, waste spark may overheat them at continuous high RPM operation, but I didn't test this specifically.
JasonC SBB is offline   Reply With Quote
Old 05-29-2015, 02:34 PM   #31
I'm Miserable!
 
Join Date: Aug 2014
Posts: 130
Total Cats: -162
Default

FAB9, do you have any updates on this product??
StealthNB is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Noob to Miataturbo from MA JxPhan Meet and Greet 3 10-02-2015 03:17 AM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
01-05 Fab9 PNP COPs (used) FrankB Miata parts for sale/trade 6 09-30-2015 12:48 PM
Koni 1150 Coilover Kit drumman83 Suspension, Brakes, Drivetrain 2 09-25-2015 08:03 PM


Tags
aem, blowout, coil on plug, cop, cops, fab9 ls coil, fab9tuning, ls coils, ls truck coil, megasquirt, pencil coils, pnp, spark blowout

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 04:39 AM.