DIY Turbo Discussion greddy on a 1.8? homebrew kit?
Sponsored by:
Sponsored by:

COP coil on plug Dwell Question

 
Old 05-21-2008, 10:40 PM
  #1  
Newb
Thread Starter
 
Join Date: Oct 2006
Posts: 1
Total Cats: 0
Default COP coil on plug Dwell Question

I am about to install my COP system (Toyota COPs) on my 99 Miata. In reading the various COP threads here I have seen a recommendation for setting dwell at “3.5 ms cranking and 2.5 ms at 12 Volts” and another thread which said that they couldn’t get the COPs to fire "with less than 5.0 ms." My Hydra system has the following dwell values versus system voltage for the stock coil packs:

10.0 V = 7.88 ms
10.3 V = 7.60 ms
10.7 V = 7.16 ms
11.0 V = 6.68 ms
11.3 V = 6.20 ms
11.7 V = 5.76 ms
12.0 V = 5.40 ms
12.3 V = 5.28 ms
12.6 V = 5.24 ms
13.0 V = 5.08 ms
13.3 V = 4.76 ms
13.6 V = 4.52 ms
14.0 V = 4.28 ms
14.3 V = 4.08 ms
14.6 V = 3.92 ms
15.0 V = 3.08 ms

Anyone have a recommended curve for running the COPs and what is the basis for your recommendation. Also, under normal conditions the system is running at about 14.5 V at the ECU.

Thanks.

Bob
TurboBob is offline  
Old 05-21-2008, 11:01 PM
  #2  
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,140
Total Cats: 6
Default

Use 2.5 ms running dwell and see how well it works. The guy running 5.0 ms because it didn't work right otherwise has a unique problem.
We have found the stock miata wiring to be insufficient to power the COPs without a capacitor installed, it seems to help greatly. That is something to consider when installing your COPs.
cjernigan is offline  
Old 05-21-2008, 11:51 PM
  #3  
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago. (The non-murder part.)
Posts: 29,302
Total Cats: 2,912
Default

With 6600uf worth of cap between +12 and GND in the COP harness, I'm running with no problems at 12v = 2.5ms, cranking = 3.5ms.

Try it and see. If you get misfires at higher MAPs, then you may need slightly more. If not, you don't.
Joe Perez is offline  
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
StratoBlue1109
Miata parts for sale/trade
21
09-30-2018 01:09 PM
nick470
MEGAsquirt
7
06-16-2017 01:53 PM
FrankB
Miata parts for sale/trade
6
09-30-2015 11:48 AM
drumman83
Suspension, Brakes, Drivetrain
2
09-25-2015 07:03 PM


Thread Tools
Search this Thread
Quick Reply: COP coil on plug Dwell Question


Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.