Coils
- Thread starter Fubar
- Start date
- Aug 25, 2006
- 4,436
Steve ??? did exhaustive testing on coils with his gal on the dyno a couple years ago and as I recall he did not find a better alternative to the OEM
What is the problem; blow out or ?
If you cannot find it doing a seach email me and I will get you in contact with him.
Takes care
Shadowman
What is the problem; blow out or ?
If you cannot find it doing a seach email me and I will get you in contact with him.
Takes care
Shadowman
Yes, we are seeing a VERY ruff line above 6000rpm. We actually converted the BAP to a boost-a-spark (easy switch) so we can get 18v to the coils. The line it somewhat smoother with the BAS turned on but the problem persists either way. Our guess is that it's either bad plugs or a bad coil. We have MSD coils on hand but I wasn't sure if they were inferior or not. The shop is closed so nothing can be done until tomorrow morning. I am leaving for the mile by noon.
- Aug 25, 2006
- 4,436
Fubar; I suspect that Shawn is working with you and he is sharp; increasing the voltage could push the OEM coils over the top however IMO the MSD coils even without looking at their spec's are likley better able to manage it. The issue could also be the PCM and and how it is managing them.
Now when you say very rough; I see certain picture in my mind. Can you email me a graph with the OEM setup and the BAS in place?
All the best
Shadowman
tmcphail
GT Owner/Vendor
Your disdain appears to be misguided. I went down this path years ago and the best route I found was the stock coil with the grenatelli inserts. Aftermarket coils exacerbated the problem.
This wouldn't surprise me at all. It's interesting that so many people have faced "this problem." Why is it so difficult to make a smooth power curve on these engines? The SCT software just doesn't provide the latitude to modify the things we would like to change. Although this issue isn't a direct result of the software's short comings, it is costing me power in other places. I'm not trying to trash SCT, for the Ford ECU, it's the best option. Maybe I should just complain about the ECU.
tmcphail
GT Owner/Vendor
The SCT software just doesn't provide the latitude to modify the things we would like to change.
Which is what precisely ?
Which is what precisely ?
BlackICE
GT Owner
Maybe changing the duty cycle (dwell) on the coils. My understanding from reading other boards is that the stock ECU limits the dwell time on the coils. That isn't a problem with the stock coils, but if you change to coils needing a longer saturation time, the stock ECU can't do it. My guess is the limit is there to safeguard the coil drivers, or coils from overheating.
Right now my big issue is injector timing. I can either put it where is needs to be for power (+35hp) or I can put it where it need to be for low rpm (good idle characteristics). I need the timing to move with rpm or manifold pressure or something else. Any input would be greatly appreciated. Coils/ignition is another matter altogether, I have never seen a "smooth" power curve on a GT. It is just really bad on my car right now, but heat is probably playing havoc with the coils also. We worked the car pretty hard on the dyno yesterday.
Sorry if this is so obvious it is silly (it probably is knowing the competence of those you have working on the issue) but have you gapped the plugs really tight? Boost really likes to blow the spark out. Also, any chance that indexing the plugs (big pain in the deep heads of the GT) would help?
The obvious solutions are often over looked so keep the ideas coming. However, we have run the gap down to .22 The SCT operator is saying to go back up and my tuner is saying he runs .18 on race cars all day. We are going to start testing shortly.
tmcphail
GT Owner/Vendor
What Mark is referring too isn't an issue of blowout. Anyone that has experienced that one time whether its on the street or the dyno knows its pretty violent.
The car really likes .18 spark gap up top but we had to take 15* out of idle timing to get it to run smooth down low. The power cruve looks much smoother now... not much more hp but 50 more trq.
*sigh* we are getting there
*sigh* we are getting there
BlackICE
GT Owner
I find your thread very interesting and i am amazed at your deication. I'm not sure if this will help at all and you probably already know this but here is a picture anyway. i think this was taken at Accufab.?
Good luck.
Yep, Accufab. I think John was using a Motec ECU to control them. If you use a stock ECU you would have to add 8 coil drivers to it.
For one the stock coils only can handle 2.0mills seconds of dwell time. 1.6 is stock. Boost a spark will not benifit the coils at all. At 2.0ms of dwell the coil is fully charged and they can only handle 6.5 amps of power and after that it just overheats the coil. The best thing todo is run the spark plug tighter on gap. .15 to .20.
I have got tests of the coils and what happens with dwell, and current.
I have got tests of the coils and what happens with dwell, and current.
This is also the reason i put a Big Stuff 3 Fuel injection system on my car. So i can control dweel with rpm and injector timing. No Maf sensor so really big intake is possible. I now have a kit todo these on the GT'S with stock coils as the big stuff 3 runs a ls1 coil and that makes it a pain in the ass for mounting coils and looks.
Fantastic post, very informative (completely over my head) but my tuner said it sounded like a man that knows his stuff. We will disconnect boost a spark. Thanks for the input.
BlackICE
GT Owner
Another interesting photo to ponder however we dont have room for something like this.
I know it wont help your problem i am just amazed what people are doing with these modular motors these days.
Interesting exercise, but why would I do that when individual coils have more potential?