High Energy Ignition (HEI)

Some selected posts from another thread, just to get this thread started:

Quote:

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Originally Posted by content22207

I know several owners, myself included, who are running true HEI with excellent results.

Bear in mind that ignition coil secondary voltage is directly proportional to its input. You can not run only 6-8 volts into a high winding coil and expect anything close maximum rated output (most HEI coils are rated at 12-14 volts input). You will get more secondary voltage than a stock Bosch coil simply by virtue of the higher number of windings, but certainly not anything close to 40,000 volts.

Bill Robertson
#5939

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Quote:

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Originally Posted by ramblinmike

Are you running 12v to the coil with the stock Bosch amp or the Duraspark you were running? I know guys run 12v to the Duraspark all the time.

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Quote:

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Originally Posted by content22207

I am running 12.5 volts into a Pertronix coil. Voltage is something like 8 or 9 volts to the Bosch ECU at the other end. I was only test driving a Duraspark unit for Byrne. He gave me his dead Bosch unit, which I will use to make another adapter to carry with me in case my ECU dies.

My resistor grid is wired in parallel (that is how I get 12.5 volts into the coil):
Attachment 4258
Pertronix coils can of course handle full charging voltage no problem. I only step it down for the ECU's benefit. I don't trust Bosch ECU's any further than I could throw one of the damn things. If I was running an original Ford Aerospace Duraspark ECU, I wouldn't reduce input voltage at all.

The biggest advantage of HEI is the ability to open up the plug gap. .026" is ridiculously small. No wonder stock DeLoreans run like crap. The benefits of wider plug gaps have been known for decades. Nearly every other manufacturer was already running .05" plug gaps when DeLoreans were new in the showroom. GM introduced HEI in 1971. DeLorean ignition was obsolete even before these stupid little cars were nothing more than a stainless steel fantasy in the back of JZD's mind. The man was vice president of the company that pioneered HEI, for crying out loud -- he should have known better.

Speaking of which: DO NOT OPEN YOUR PLUG GAP IF YOU ARE STILL RUNNING SUBSTANDARD DELOREAN 6-8 VOLTS INTO THE COIL, NO MATTER WHAT KIND OF COIL IT IS (can I hear an "Amen" Steve?). The stock resistor grid is really better suited for breaker points than breakerless ignition.

Bill Robertson
#5939

You can get away with smaller plug gaps in high compression and forced induction engines because the mixture is easier to ignite. Some owners claim that larger plug gaps are actually counter productive in those circumstances.

In a low compression engine, like the stock DeLorean PRV, the mixture is harder to ignite. Leaning the mixture out for fuel economy and emissions exacerbates the situation. That is one reason American manufacturers were so quick to adopt HEI in the early 70's.

A Society of Automotive Engineers' study from the time: http://dmctalk.org/showthread.php?65...ull=1#post7222
I found it particularly fascinating that wider plug gaps also yielded benefits similar to increased gap projection (you don't need to change spark plug length -- just open the gap up).

Bill Robertson
#5939

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Quote:

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Originally Posted by ramblinmike

Regardless of everyone's position on the stock vs. modified coil/ignition, everyone should at least agree that the stock plug gap is pretty small.

As the years went on every car manufacturer has found a way to increase secondary voltage and with it the plug gap.

A stock system works well. That has been proven through millions of real-world miles cars with a similar setup have put on the road. What I don't understand is why a car company would base their 'new' electronic ignition around the use of an off-the-shelf coil. If they were putting the money into developing this new system why not develop a new a new coil to take advantage of the breakerless ignition?

Bosch wasn't the only one to do this. Ford did the same thing over here. I just don't understand why they would stop at 6-8v at the coil. They knew in the 60's that increased primary voltage was the way to go for performance and economy. They wouldn't have resorted to dual-point distributors (and the associated headaches) if they didn't.

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Quote:

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Originally Posted by content22207

In the 1970's Ford used 10.5 volts primary (Duraspark breakerless ignition). Plug gaps were .044".

Bill Robertson
#5939

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Quote:

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Originally Posted by ramblinmike

Here's where I found the info I was basing my statement:

http://www.autozone.com/autozone/rep...00c15280077d43

From the above troubleshooting guide:
"If no spark occurs, measure the voltage on the battery side of the coil.

Less than 6 volts - Repair the wire carrying current to the battery terminal of the coil and repeat test.

If voltage is 6-8 volts - Substitute, but do not install, a known good module and repeat the test. If spark then occurs, reconnect the original module to verify its being defective. Replace as required. Refer to step 10 if the battery voltage is present."

This is not a Ford document FWIW.

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1978 Lincoln, stock wiring before the coil (Duraspark ECU):
Attachment 4291

Bill Robertson
#5939

From another thread:

Quote:

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Originally Posted by David T

All too often someone gets the idea that bolting in a new, different part will give them better performance, gas mileage, reliability, <blank> etc. You can fill in the blanks. If it was that easy the original manufacturer would have done it. In some cases they actually do see some improvement only because the part they replaced was old, worn, the wrong one, or defective. There is little if anything to be gained by putting "performance" parts into the ignition system. If every part you could bolt on to the car added the performance each claimed you could theoretically double the HP of the car. Who is going to believe THAT! A BIG problem with deviating from stock is that it becomes near impossible for anyone to help when the car has a problem. Too many variables and no good place to start troubleshooting. For a street driven car reliability is very important. To a big extant more important than a small, temporary increase in performance. Another thing to remember is most systems are like chains. Only as strong as the weakest link meaning if you don't improve the WHOLE system, improving one part of it does not improve what the whole system can do. As Martin said, "Show Me!" Put it on a dyno and show the numbers. Till then it is just a pretty and expensive part. I swear that my car always runs better after I clean it or change the oil. A very subjective effect. After spending money on a performance part you expect the car to run better, faster, etc!
David Teitelbaum

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Bullshit.

Bill Robertson
#5939

It never ceases to amaze me that a small, but supposedly "guru," contingent of this community close their eyes, stick their fingers in their ears, and shout "la la la, I'm not listening" as loud as they can whenever the subject of DeLorean ignition comes up.

In 1972, the Society of Automotive Engineers determined that ignition with higher secondary voltage, larger plug gaps, and longer spark duration improved combustion. "La la la. I'm not listening."

Nearly every car manufacturer (ie: Ford, General Motors, Chrysler, Datsun, Honda, Toyota, Subaru, Mazda, et al) started installing ignitions with higher secondary voltage, larger plug gaps, and longer spark duration in the early 1970's, and has never gone back to earlier spec ignition since. "La la la, I'm not listening."

High voltage coils cost half as much as low voltage Bosch coils. "La la la, I'm not listening."

The very cars DeLoreans were supposed to compete within 1981 had already been running HEI for years (DeLorean ignition was out of date new on the showroom floor). "La la la, I'm not listening."

Excuse me for a moment while I pick up the eyeballs that just rolled clear out of my head.

Bill Robertson
#5939

Quote:

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Originally Posted by ramblinmike

... What I don't understand is why a car company would base their 'new' electronic ignition around the use of an off-the-shelf coil. If they were putting the money into developing this new system why not develop a new a new coil to take advantage of the breakerless ignition?...

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Something just occurred to me: AM radio may have been the limiting factor. AM frequencies are very liable to ignition interference. On my own cars it shows up as a distinctive "tick tick" at idle, rev'ing to a continuous static hum. I'm pretty sure Europeans listened to a lot of AM radio in the 1970's. Bosch igntion may well be designed not for combustion efficiency, but rather not to interfere with AM radio reception. How else do you explain the resistor in our rotor buttons....

Bill Robertson
#5939

I have always reasoned that DeLoreans have the ignition systems they do because it was quick and cheap to simply take the PRV lock, stock, and barrel from another application and drop it in. Everything I have learned about these cars suggests to me that if they had simply had more time they could have had a better product, but time was against them so we got what we got. I wouldn't be surprised to find Peugeot, Renault, and Volvos of the late 1970s using the PRV V6 to have the exact same ignition setup -- in fact, I'd expect it.

Farrar

Volvos do. Even the ECU is identical (helpful hint if anyone has the opportunity to scavenge a spare from a junkyard).

Bill Robertson
#5939

Quote:

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Originally Posted by DCUK Martin

*sigh*. No, I'm asking you to prove that with your ignition modification, you achieved anything more than could be achieved with new stock components.

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My ignition is now 1981 Mustang caliber. Combined with its Mustang carburetor, #5939 is exactly 37.615% faster than a factory spec DeLorean (even with new components).

Bill Robertson
#5939

Quote:

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Originally Posted by content22207

My ignition is now 1981 Mustang caliber. Combined with its Mustang carburetor, #5939 is exactly 37.615% faster than a factory spec DeLorean (even with new components).

Bill Robertson
#5939

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Have you ever taken #5939 up to speed? I brought 16510 up to 105 mph but got scared and slowed down since my tires are only rated for 108 mph.

Didn't you once say that your engine might have slightly different cams because it was originally intended for stationary use? I would add that to your list of deviations from stock DeLorean trim, if so.

Won't matter anyway -- Martin won't believe anything without a dyno printout.

What's the deal, anyway? Martin's happy with his car, and you're happy with yours.

Farrar

Quote:

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Originally Posted by stevedmc

Have you ever taken #5939 up to speed? I brought 16510 up to 105 mph but got scared and slowed down since my tires are only rated for 108 mph.

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I still have a speeding ticket on my insurance, and now am CDL for the church, so I stick to 5 MPH over.

Plus I would be a little self conscious to see helicopter coverage of my performance modified little silver car embarrassing pursuing North Carolina troopers on national news.

Bill Robertson
#5939

Quote:

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Originally Posted by Farrar

Didn't you once say that your engine might have slightly different cams because it was originally intended for stationary use? I would add that to your list of deviations from stock DeLorean trim, if so.

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Test driving carb conversions, and comparing their seat of pants performance to final installation on other cars, has led me to doubt that earlier suspicion.

My manifold does move more air than either a K-Jet manifold or fabricated manifolds because its runners have square cross sections, not round. I also have a big central plenum common to all cylinders (single plane) rather than a dual plane design. The combined effect is to move my power band towards higher RPM's, which anyone who has ridden with me can confirm I reach very quickly.

As soon as I capture and edit down a short segment of video, I will post visual evidence that my car is faster than a stock DeLorean.

Bill Robertson
#5939

I think Martin's beef is Bill's willingness to share his happiness that has only been tested on his car, and maybe a few other , for a relatively short amount of time then claim outstanding results from his personal use as hard tested facts.

Quote:

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Originally Posted by David T

All too often someone gets the idea that bolting in a new, different part will give them better performance, gas mileage, reliability, <blank> etc. You can fill in the blanks. If it was that easy the original manufacturer would have done it. In some cases they actually do see some improvement only because the part they replaced was old, worn, the wrong one, or defective. There is little if anything to be gained by putting "performance" parts into the ignition system. If every part you could bolt on to the car added the performance each claimed you could theoretically double the HP of the car. Who is going to believe THAT! A BIG problem with deviating from stock is that it becomes near impossible for anyone to help when the car has a problem. Too many variables and no good place to start troubleshooting. For a street driven car reliability is very important. To a big extant more important than a small, temporary increase in performance. Another thing to remember is most systems are like chains. Only as strong as the weakest link meaning if you don't improve the WHOLE system, improving one part of it does not improve what the whole system can do. As Martin said, "Show Me!" Put it on a dyno and show the numbers. Till then it is just a pretty and expensive part. I swear that my car always runs better after I clean it or change the oil. A very subjective effect. After spending money on a performance part you expect the car to run better, faster, etc!
David Teitelbaum

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+1
100%

Quote:

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Originally Posted by content22207

You will get a small performance boost. High winding coils produce more secondary voltage than low winding coils can from the exact same input voltage.

Bill Robertson
#5939

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I agree with the others -- Not by changing out a good stock coil alone. The stock coil can supply all the energy the stock plugs need to fire correctly. The perfect coil will only produce enough energy to fire the plug, no matter how many gazillawatts it has "in reserve".

Now if you changed other things, like the plug gap, plug itself, cap-rotor gap, button resistance, etc. you may have stumbled on a combination that performs better and I too would like to see it -- strictly ignition mods, not what you had to do to your carb setup to get it all where you liked it (another interesting story).

http://www.youtube.com/watch?v=1MjA4R6t1Fs

Bill Robertson
#5939

Quote:

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Originally Posted by content22207

http://www.youtube.com/watch?v=1MjA4R6t1Fs

Bill Robertson
#5939

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....:ehh::question:

Ok, this video shows us that one car paced traffic and another didn't. I wouldn't hold your breath on Mythbusters to come a knocking as an adviser on how to test and compare things. Now these guys may :D:

http://www.youtube.com/watch?v=iZhEcRrMA-M

Quote:

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Originally Posted by sean

....:ehh::question:

Ok, this video shows us that one car paced traffic and another didn't. I wouldn't hold your breath on Mythbusters to come a knocking as an adviser on how to test and compare things.

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Oh boy, that is a stretch. So the delorean with the camera cant even outrun the truck next to it going 35? Agreed, the camera car isnt even trying.

I simply asked a simple question: of the two DeLoreans in that film clip, which one accelerated faster -- the one in front or the one in back?

This isn't a hard question boys. Even if you make a blind guess, you have a 50% chance of getting the correct answer.

Bill Robertson
#5939

Quote:

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Originally Posted by content22207

I simply asked a simple question: of the two DeLoreans in that film clip, which one accelerated faster -- the one in front or the one in back?

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And this is telling us what? The guy in the back chose not to accelerate? The guy in the back is in a sluggish automatic? The guy in the back is running on solar power?

Quote:

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Originally Posted by content22207

I simply asked a simple question: of the two DeLoreans in that film clip, which one accelerated faster -- the one in front or the one in back?

This isn't a hard question boys. Even if you make a blind guess, you have a 50% chance of getting the correct answer.

Bill Robertson
#5939

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Bill, who cares if they were not engaged in a power contest. Which one slowed faster, or had better fuel economy in that film? Who cares, its not relevant. If the lead car passed a viper does that mean its faster. Even if the viper was parked?

Nobody's trying to prove anything -- I just asked a simple question: of the two DeLoreans in that film clip, which one accelerated faster?

If you don't know, at least guess.

Bill Robertson
#5939

Quote:

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Originally Posted by content22207

Nobody's trying to prove anything -- I just asked a simple question: of the two DeLoreans in that film clip, which one accelerated faster?

If you don't know, at least guess.

Bill Robertson
#5939

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what about my questions? Will they go unanswered? How will I ever sleep tonight?

Quote:

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Originally Posted by content22207

Nobody's trying to prove anything -- I just asked a simple question: of the two DeLoreans in that film clip, which one accelerated faster?

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Bill's

I'm pretty sure the only way to have test 2 cars in this fashion is to actually call up the Stig and have him drive both for time trials. Until then, the video means nothing.

If the car in back accelerated faster than the car in front, the car in front would have been rear-ended.

Good thing Bill's car was in front, I guess. :lol:

Farrar

http://www.youtube.com/watch?v=mdboKxsONnQ

Bill Robertson
#5939

Idea for DCS 2012: drag-racing against Bill Robertson.

Farrar

Quote:

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Originally Posted by Nicholas R

I'm pretty sure the only way to have test 2 cars in this fashion is to actually call up the Stig and have him drive both for time trials. Until then, the video means nothing.

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The video proves that Bill's car was accelerating faster than the Delorean behind it. Did you notice the driver zoomed in with the camera instead of speeding up to get closer?

The video doesn't prove that Bill's car is faster, it proves it was moving faster. There are various reasons as to why it was moving faster which could be anything from the driver or the car iteself.

Quote:

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Originally Posted by stevedmc

There are various reasons as to why it was moving faster which could be anything from the driver or the car iteself.

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Or both.

Does Bill's car + Bill driver = toasted stock DeLorean cheese?

Bill Robertson
#5939

Mmmm..... toasted cheese.....

http://grilledcheesesandwich.org/wp-...lledcheese.jpg

What we need at DCS-12 is a dyno. But my priority is reliability and not increased power. Now if the changes increase MPH then I'm all for that.

Quote:

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Originally Posted by content22207

Or both.

Does Bill's car + Bill driver = toasted stock DeLorean cheese?

Bill Robertson
#5939

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Very true. You could have all the performance mods in the world and the car wouldn't go faster if the driver never pressed the gas pedal.

This is slightly off topic but have you ever noticed people in huge pickup trucks, SUVs, and even Hummers that slowly crawl over speed bumps? I have never understood that, expecially with Hummers. These people drive in freaking all terrain vehicles and are worried about some puny little bump messing up their Hummer! When I am in the Delorean I do slow down for speed bumps but when I am in the Geo Metro I show no mercy to speed bumps.

At the risk of feeding the fire (and because I have a genuine interest in the topic) I switched to HEI when I first worked on the car. I had done a tune-up previously but the car was still acting funny, so I switched to a Blaster 2 and widened the plug gaps (I was already running MSD wires).

I can't say if it made a huge difference in performance as the car was still acting funny but it certainly helped it start faster. Combined with a new starter, the car usually fires before it even turns over a full revolution. Even with the old starter, the ignition improvement significantly shortened the number of turns before the engine caught.

I am running an MSD-specific ballast resistor instead of the factory setup, as the datasheet for my coil specified using it if there was a resistor in the car originally.

Everyone seems to be overlooking the fact that messing with the ignition system has an effect on emissions. It may not matter to any of us now but DMC had to make an engine package that was certifiable by the US EPA. To do that required intense testing with a certain configuration of components. Once certified that configuration was "set in stone" and couldn't be changed easily and without more testing. There is another factor. 30 years later we know some things we didn't know then and there are things available now that weren't back then. For instance the stuff they call gasoline thesedays. There are also performance parts. Anyway there is some potential for improvement in the ignition system but you have to experiment and hit on the right combination and then you have to fine tune it so it will stay in tune for an extended period. As an example, spark plug gaps change over time. Comparing Bill's car to other Deloreans is difficult with all of the modifications he has done to his car. A dyno would be a good, objective test with the least amount of variables. Dyno time costs money. Put your money where your mouth is, I say. Seat-of-the-pants testing is too subjective and is meaningless.
David Teitelbaum

Quote:

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Originally Posted by David T

Everyone seems to be overlooking the fact that messing with the ignition system has an effect on emissions.

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According to the Society of Automotive Engineers, increasing secondary voltage and widening the plug gap (and lengthening spark duration) "reduce the cyclic combustion variation and the unburned HC."

Does anybody bother the read the scientific studies I post, or do you all reflexively stick your heads in the ground and cry "don't mess with John DeLorean's masterpiece!"

You all are laboring under the mistaken impression that DeLorean ignition was optimized. It wasn't. It was good enough -- that's it. There is plenty of room for improvement, if only to bring it up to 1981 Mustang standards.

Bill Robertson
#5939

Quote:

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Originally Posted by AdmiralSenn

I am running an MSD-specific ballast resistor instead of the factory setup, as the datasheet for my coil specified using it if there was a resistor in the car originally.

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Go back and re-read the instructions carefully -- it is possible your coil handle full charging voltage (the Bosch ECU, however, is a different story, although mine is handling whatever comes out the far side of 12.5 primary OK).

This is a Pertronix coil on my 1969 Lincoln engine (transplanted into a 1979 vehicle):
Attachment 4380
Primary voltage is only 12.5 because the engine is idling about 600 RPM -- it'll jump up to 13.8 when rev'ed.

Bill Robertson
#5939

Quote:

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Originally Posted by content22207

Go back and re-read the instructions carefully -- it is possible your coil handle full charging voltage (the Bosch ECU, however, is a different story, although mine is handling whatever comes out the far side of 12.5 primary OK).

This is a Pertronix coil on my 1969 Lincoln engine (transplanted into a 1979 vehicle):
Attachment 4380
Primary voltage is only 12.5 because the engine is idling about 600 RPM -- it'll jump up to 13.8 when rev'ed.

Bill Robertson
#5939

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I'm sure it will handle it - in fact I ran the car for a few weeks that way before I found that line in the directions, and nothing bad happened. But I figured that it really isn't hurting anything and the part was cheap enough that I was happier following the manufacturer's directions.

Maybe if/when I switch to controlling spark through my MS ECU I might drop the extra resistor but the worst consequence of installing it is a blistered fingertip from when I poked it by mistake.

What is your primary voltage? My DeLorean runs .25 ohms of resistance, which knocks the primary side down to 12.5 volts when charging (10-11 volts while cranking IIRC). As stated, my Bosch ECU hasn't had any problems with that yet. Of course a Pertronix coil must have more internal resistance than a Bosch coil simply due to the increased number of windings, so the ECU may be seeing similar voltage on the far side.

Bill Robertson
#5939

I have no idea off the top of my head, honestly. I'd measure it but without battery cables it's a little hard to start the car. :wrenchin:

I do know that the last time I checked voltage at the coil it was lower than it should have been, something like 10.6 volts, but given the issues I'm correcting with the wiring, that number is artificially low. I don't remember what it was prior to the resistor but it wasn't much higher.

I think the resistor I have is .8 ohms. When my battery cables get here and I rewire the car I'll be able to measure it again, and it'll be accurate this time.

I've actually never argued that Bill's car isn't faster than a stock DeLorean. It almost certainly is. The Alpine GTA Atmo with slightly different cams, ignition timing (advance weights) and a twin Solex carb setup but otherwise identical transmission and ignition systems is a heap quicker than a DeLorean - 156hp IIRC. They didn't have the mpg or emissions figures to hit that DMC did. I'm pretty sure Bill's current setup wouldn't meet those either.

My beef is Bill's claims that any of his mods are "better" without qualifying, in accurate specific terminology why. ("Because Ford used it for years" doesn't count).

Quote:

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Originally Posted by Ron

I agree with the others -- Not by changing out a good stock coil alone. The stock coil can supply all the energy the stock plugs need to fire correctly. The perfect coil will only produce enough energy to fire the plug, no matter how many gazillawatts it has "in reserve".

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And *that* is my single reason for doubting Bill's many claims. I experienced many a headache trying to get my turbo engines to ignite properly under boost and the only coil that'd do it was a stock one. The plugs were changed for NGK BP7EFVS's which are a cold plug used by the GTA boys. HT leads were correct Bougicords (the dizzy cap has different connectors than the DeLorean).

Bill's crowing about better coils means nothing without taking the performance to the point where it fails. Anything up to that point will work fine, but won't actually be any better than a properly working stock system in an engine being accurately fuelled. I add this last caveat because in a rich-running engine, a hotter spark will ignite the mixture more readily, but that doesn't make the ignition system "better".

Quote:

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Originally Posted by DCUK Martin

Bill's crowing about better coils means nothing without taking the performance to the point where it fails. Anything up to that point will work fine, but won't actually be any better than a properly working stock system in an engine being accurately fuelled. I add this last caveat because in a rich-running engine, a hotter spark will ignite the mixture more readily, but that doesn't make the ignition system "better".

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Obviously you haven't bothered to read the SAE paper I posted. They proved that increased spark energy ignited LEAN mixtures better.

You stick with your chicken bones and tea leaves -- I'm going with the scientists.

Bill Robertson
#5939

No I didn't bother wading through the link you posted because on the occasions I have bothered I usually discover that you mis-read or misunderstood it anyway. Let's call it a less-than-optimum mixture condition then.

So you'd fix a lean-running engine by fitting "better" ignition?

I really wish you would "go with the scientists". We wouldn't argue anything like as much.

That paper was published on the eve of widescale HEI adoption over here. In its historical context, manufacturers for the North American market were just beginning to adopt leaner fuel mixtures. It is no accident that HEI caught on like wildfire.

Compared to nearly every one of its North American contemporaries, DeLorean ignition specs are woefully out of date. Both coil voltage and spark plug gap more closely resemble 1971 practice than 1981 practice.

Bottom line: the ignition system used by DeLorean is quite badly matched to its lean mixing fuel system.

That is not mere opinion -- it is SAE research, vetted by Lucas, Ford, and Champion Spark Plugs, and historical comparison of DeLorean against all of its North American contemporaries.

Bill Robertson
#5939

Quote:

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Originally Posted by DCUK Martin

No I didn't bother wading through the link you posted because on the occasions I have bothered I usually discover that you mis-read or misunderstood it anyway. Let's call it a less-than-optimum mixture condition then.

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Authors' [AC Delco engineers] conclusions, found on page 60 (14th page of the scan):

"The conclusions reached as a result of this investigation are summarized below. Even though these conclusions are based on tests obtained with one basic engine, the trends observed should be similar to what would be expected of all modern engines.
1) The cyclic work measurement, in conjunction with measurement of emission levels, provides one satisfactory method for evaluating engine performance.
2) Extended gap locations, wider gap size, and higher spark energy levels [my emphasis] are the most significant parameters that reduce cyclic combustion variation and unburned HC. Smaller electrode side shows similar effects, but these effects are less pronounced.
..."

The rest of the paper is just boring data that verifies the above, and commentary from Lucas, Ford, and Champion Spark Plug agreeing with the authors' findings.

Bill Robertson
#5939