this afternoon, I popped the top from my HEI distributor (Already curved from dyno tuning) and installed an Accel high voltage coil in it's place.

Tell me I'm crazy but I think it improved my mid-range power. Around town driving feels like it's got more ***** now. Is it my imagination? Haven't been in any place yet today that would give me enough room to really GET ON IT but around town it sure feels better.

I'm using Accel Shorty plugs and am wondering if I should go from .045 gap to .050 ?? The heads are GM Cast Iron Heads.

 

No takers on this one??? :conehead :hat

 

Supercoils is the first thing I do to a car! You will feel a very slight difference in acceleration from the stock coil. But remember, your coil is only as good as the wires, plugs and electrical system that support it. I increased by my alternator output from 13.8 to 14.9 volts just to get more secondary voltage, the accel coil can handle it but stock coils will literally melt. This is the extent of my knowledge with these.
~Christian

 

How much was it?

 

How much was it?

Cost about fifty bux plus shipping.

 

I just got the same from a friend for $10 :D (At the same time, got a HE 268H cam and matched valvesprings from him for $50, am I rakin' in the deals or what?) Starting became alot easier, I've noticed. I don't have the best wires yet, and Delco plugs, but I don't know if I feel a power difference or not. I'm not very good at feeling performance increases for some reason... :confused: Anyways, couldn't hurt, should support any future mods :yesnod:

-Chris

 

Sounds like a good upgrade when I build a new engine next winter.

 

Some of the classes of racing that I build motors for require a stock appearing distributor so I have done a lot of dyno testing with HEI distributors. I have used every part made that I know of from stock delco HEI , Accel HEI, Pertronix Flamethrowr HEI, MSD HEI, Pro-Star HEI, Jacob ignition HEI and all of there coils and all of their modules and I have NEVER been able to find any measurable HP difference in any of them. They are all good products but none are better than any of the others. A stock Delco unit is just as good as all the others. I all ways recomend to a customer to get which ever one they can get the best price on.

The misconception with coils is that more voltage is better. That is not true unless more voltage is needed. A coil will only produce eough voltage to arch the gap in the spark plug. If only 10K voltage is needed then the coil will only produce a 10K voltage spark even if the coil is capable of producing a 50K voltage spark.

In free air (uncompressed) it is easier to produce a spark than under compression. The higher the compression the more difficult it is to produce a spark. I have used stock HEI distributors on motors up to 13-1 compression at 7000 RPM and they have made the same horsepower as any of the so called performance distributors.
On a low compression (under 10-1) street motor the stock delco HEI coil will produce well over the requirements to arc spark plug gaps even up to .060.

I have many customers using stock HEI distributors (or any other HEI) with 16v systems without any problems.


[Modified by Pete79L82, 12:16 AM 4/23/2003]

 

Pete I was expecting zero change BUT then there is the seat of the pants feel. Anyway I'm happy with it but wondering still about that plug gap. How do ya feel about going to .050 from .045? :nopity

 

Now that is the way to go.

 

I have one on my '91 C4 and really like it. :thumbs:

 

If it seems like an improvement, it's made you happy. And that's all that counts! :cheers:

BTW: Whenever you increase coil output voltage, you should plan on replacing your cap, rotor, wires, and plugs more often. The higher voltage tends to fry them quicker...

 

Since we're on the subject, I've got an Accel coil-in-cap setup. How long can I run this before I have to change the coil? I've never heard anyone mention the duration one of these will last. Any ideas?

 

It is possible that your old coil was getting weak and you do feel a change. As long as you are happy all is good! :yesnod:


I know others will disagree but I am of the belief to run as small of a gap as you can before power drops off. Others will say to run as large of a gap as you can before power drops off, but I have found that all this does is put unessessary stress on the ignition system. With a standard 12v system I have found that .045 is about the max before you do not see any more gain from increasing the gap. A G-tech or some runs down the track will tell you for sure.


An HEI coil should easily go 10 years or more as long as you keep the rest of the ignition system in good working order. Bad plug wires, worn plugs, carbon tracked caps, burnt rotors, excessively wide gaps all put extra stress on the coil and can drastically reduce its life span.


Pete

 

Thanks For the Info, Pete :cheers:

 

Pete, I agree with you 110%.....


I find the largest failure with stock HEI coils is the crimp connectors on the primary winding....scrape and solder...job done....causes intermittant dead outputs....caught one pants down one day..... another one is that sending coil under the rotor....on the base....needs take whole dist. apart to fix it....

GENE

 

IN talking with spark power, I installed my MSD 6A last night. Simple installation. The installation took about 45 minutes. Upon testing teh engine came to life in about half a second. I am running stock GM HEI distributor. The MSD has made a world of difference in just the initial starting of the car from cold. For such an easy installation I would suggest this for all! It even improves your gas milage. I might be getting about 12 MPG stop and go in my 454. We will see... :thumbs: :auto: