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 Forums > Porsche Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered
 
Join Date: May 2003
Location: Woodlands TX
Posts: 3,946
MSD high vib coil with stock CDI

Hey guys I searched and read bunches of posts all over pelican and the internet.


I am tracking down a spark issue with my 84 and bought the MSD coil. At first I thought I didnt need to add a resistor but then I saw a post that said I did.

I ordered the big voltage dropping Ballast resistor from MSD, but now Im not sure if I need to use it or not. It is not trivial to find somplace tidy to put it out of the way under the IC.


Does anybody have any definitive insight on this.

Thanks
Aaron

__________________
84 930
07 Exige S
Old 12-21-2015, 07:50 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered
 
T77911S's Avatar
 
Join Date: Oct 2006
Location: MYR S.C.
Posts: 17,321
since you have one i would try it with and without.
ballast is for current limiting or reducing.
the MSD coil DOES have a lot less primnary resistance than a bosch but with a CD that may not matter.

how do you know it is spark related

could be
air leak
injector
plug wire
fuel dist
compression issue
valve issue
__________________
86 930 94kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
03 BMW 330CI 220K:: [__] RUNNING: [__] NOT RUNNING:
01 suburban 330K:: [__] RUNNING: [__] NOT RUNNING:
RACE CAR:: sold
Old 12-21-2015, 08:34 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered
 
Join Date: May 2003
Location: Woodlands TX
Posts: 3,946
Thanks, the car just quit running and I pulled a plug wire and put in a plug to check for spark, there was nothing there

I was going to try with and without but I thought there might be long term differences with reliability of other components. Also the Resistor is bigger and more difficult to place than I expected. It will take a bit of work to put it somewhere tidy.
__________________
84 930
07 Exige S
Old 12-21-2015, 09:20 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered
 
T77911S's Avatar
 
Join Date: Oct 2006
Location: MYR S.C.
Posts: 17,321
if the CD is good you can put the MSD coil on with no ballast and it will run.

check for power at the CD with the key on.
if you have power and have swapped the coil then the CD unit is bad.
well i say that. there is always a chance the coil in the dist is bad or the wrie from the dist to the CD is bad.
at the CD unit, ohm the 2 coil wires to the dist. i think it is around 600ohms.
listen for a high pitched whine, if you dont have that then it is definately bad,

if no power to the CD there is a relay that feeds 12v to it. check that.
it is actially a delayed action relay. it is what keeps the engine running after you tirn the key off
__________________
86 930 94kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
03 BMW 330CI 220K:: [__] RUNNING: [__] NOT RUNNING:
01 suburban 330K:: [__] RUNNING: [__] NOT RUNNING:
RACE CAR:: sold
Old 12-21-2015, 10:49 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered
 
Join Date: May 2003
Location: Woodlands TX
Posts: 3,946
The CDi makes the characteristic whining noise with the key on so I assume it has power.

My car being an earlier euro sometimes has less fancy relays than later usdm cars, though not sure if that matters here. I dont have a yellow relay for example

If the MSD coil fixes the issue should I go back and wire in the ballast resistor? I have seem some post that claim it can burn out the CDI unit if I do not.

THanks

Aaron
__________________
84 930
07 Exige S
Old 12-21-2015, 10:58 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered
 
Join Date: Jul 2006
Location: S. Florida
Posts: 7,249
Call MSD and ask them.
They know what's reliable and works over the long run with their ignitions.

I wouldn't go for a long drive or trip in a car that might burn up it's original Bosch CD ignition box because the wrong impedance coil is wired to it.
The original Bosch 930 coil and MSD coils have different impedance. I think thats another word for the primary winding wire resistance.
The only other coil i know of that has the correct impedance for the Bosch CD box is the Permatune epoxy filled coil.
Old 12-21-2015, 03:46 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered
 
911tracker85's Avatar
 
Join Date: Feb 2009
Location: Park Hills, KY
Posts: 2,459
I had two MDS blaster coils fail on my 951 not using the MSD box. now back on the OEM coil for now.

my plans for my 930 build is to replace the old electromotive with a twin plug RSR dist, and two, MSD 6AL's, MSD BTM and two High-vibration blaster coils

good luck.
__________________
Bob Cox
78 930 clone project car.
87 924S resurrect at some point.
84 928S, Ruby Red linen/brown interior - sold
86 944 turbo my new DE/track car - sold
Old 12-22-2015, 05:29 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered
 
Join Date: May 2003
Location: Woodlands TX
Posts: 3,946
Quote:
Originally Posted by JFairman View Post
Call MSD and ask them.
They know what's reliable and works over the long run with their ignitions.

I wouldn't go for a long drive or trip in a car that might burn up it's original Bosch CD ignition box because the wrong impedance coil is wired to it.
The original Bosch 930 coil and MSD coils have different impedance. I think thats another word for the primary winding wire resistance.
The only other coil i know of that has the correct impedance for the Bosch CD box is the Permatune epoxy filled coil.
OK, I Just thought somebody here would know, especially because it seems to be a really common switch and our host sells them. I would buy an oem coil but apparently the new bosch ones have life expectancy measured in min.
__________________
84 930
07 Exige S
Old 12-22-2015, 06:57 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Registered
 
Join Date: May 2003
Location: Woodlands TX
Posts: 3,946
Quote:
Originally Posted by 911tracker85 View Post
I had two MDS blaster coils fail on my 951 not using the MSD box. now back on the OEM coil for now.

my plans for my 930 build is to replace the old electromotive with a twin plug RSR dist, and two, MSD 6AL's, MSD BTM and two High-vibration blaster coils

good luck.


really that is surprising the consensus on the 911 forum is that the new bosch coils are junk, it is of course a different application though
__________________
84 930
07 Exige S
Old 12-22-2015, 06:58 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Registered
 
Join Date: May 2003
Location: Woodlands TX
Posts: 3,946
Also somebody credible in the main 911 forum said that the impedance and turn ratio is nearly identical for the bosch and MSD hi vib coil
__________________
84 930
07 Exige S
Old 12-22-2015, 07:00 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Registered
 
Join Date: Jul 2006
Location: S. Florida
Posts: 7,249
The new Bosch ones are made in Brazil. From my experience they gradually leak oil and burn out when mounted upside down on the fan housing like the original one.

If you mount them somewhere away from engine vibration and heat with the tower right side up they will last a lot longer.
The Permatune epoxy filled coil is the correct impedance for the Bosch CD box and the Permatune replacement CD box, and it's black so it looks OK upside down on the fan housing under the intercooler.
Old 12-22-2015, 07:04 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Registered
 
T77911S's Avatar
 
Join Date: Oct 2006
Location: MYR S.C.
Posts: 17,321
i put a set of clewett wires on my car. but i had him make a special coil wire with a 90 on one end.
i now have my MSD coil in its original place but turned right side up. the 90 goes on the coil end.
to top it off, i have a 930 with the inter cooler right on top of the coil and i could still do this.
had to slide it down in the braket though.

the new bosch coils are not that good.
i thought they were china made.

i dont know if the impedence is the same but the MSD coil primary resistance is a lot less.

i am going to research this more.

look in the 911 side for thread about how much current does a CD draw.

__________________
86 930 94kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
03 BMW 330CI 220K:: [__] RUNNING: [__] NOT RUNNING:
01 suburban 330K:: [__] RUNNING: [__] NOT RUNNING:
RACE CAR:: sold

Last edited by T77911S; 12-22-2015 at 10:08 AM..
Old 12-22-2015, 10:03 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
 
Reply


 


All times are GMT -8. The time now is 09:35 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 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.