Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
WydRyd's Avatar
 
Join Date: Mar 2002
Posts: 3,563
Question Twin-Plug Ignition mapping?

Curious, how does a twin plug ignition map differ to a single plug map, in terms of degress of advance etc at idle/cruise/WOT?

The reason I ask is because when I install the piggy-back ECU on my Motronics & the 964 dizzy, I'd like to setup a basic base ignition map to get me going so I can get the car to a dyno tuner for more precise mapping.

Any input appreciated
__________________
Merv
'89 911 Turbo Cab
Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition
Old 02-06-2007, 03:44 PM
  Pelican Parts Technical Article Directory    Reply With Quote #1 (permalink)
Registered User
 
David's Avatar
 
Join Date: Apr 2002
Location: Houston (Clearlake), TX
Posts: 8,568
Garage
My understanding is that you need less advance with twin plug since you'll have more complete combustion. Of course the dyno is really the place to set timing.
__________________
2014 Cayman S
2011 Cayenne Turbo
1979 930 (475 rwhp at 0.95 bar)
Old 02-06-2007, 04:56 PM
  Pelican Parts Technical Article Directory    Reply With Quote #2 (permalink)
Registered User
 
WydRyd's Avatar
 
Join Date: Mar 2002
Posts: 3,563
Sorry, yeh I meant LESS timing.

Any idea how much less timing compared to a single plug config?
__________________
Merv
'89 911 Turbo Cab
Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition
Old 02-06-2007, 05:11 PM
  Pelican Parts Technical Article Directory    Reply With Quote #3 (permalink)
Registered User
 
Join Date: May 2002
Location: Up North
Posts: 1,434
To be 100% sure, you'll need a dyno.

For mine, my max timing (non-boost) is 29 deg (from memory) instead of ~32. On max boost, I retarded mine to 16 (from 18-19).

But then I haven't checked mine against a dyno neither, so YMMV.
__________________
87 930 K27HFS/B&B/Twin-Plug... Megasquirted
Old 02-07-2007, 04:41 AM
  Pelican Parts Technical Article Directory    Reply With Quote #4 (permalink)
Registered User
 
beepbeep's Avatar
 
Join Date: Jun 2001
Location: Sweden
Posts: 5,559
Yeah. As mixture is ignited from two directions, it will combust quicker. This means that pressure will raise in more distinct manner and that you don't need as much advance in order to "wait for pressure to build up". This is also one of main reasons for twin plugs making more power: you can time the ignition so pressure spends more time pushing the piston down then before.

Correct readings should be found on dyno as it will differ from car to car. I suggest retarding it 5-6 degrees, then inching forward while measuring torque. When torque starts to drop off (or you expirience pre-ignition), it's time to back off.
__________________
Thank you for your time,
Old 02-07-2007, 06:08 AM
  Pelican Parts Technical Article Directory    Reply With Quote #5 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 09:07 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2017 Pelican Parts LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.