MSD Digital 6+
 

So I've been tossing around of buying a Digital 6+ MSD box to replace my 6a on my MSD_DIS set up. It looks as thought it would hook up just like the regular 6A does. I'm soiing the idea around then I figure I can run the 6a through the dizzy. No money not being a factor do you think it might be bennificial. I wonder if it could fire the DIS coil better than the regular 6a. Give me thought's. I don't want any F&F 17y/o posting in this thread unless you know your electronics and have allready experimented with or have direct experiance with it.

My current setup: https://www.rx7club.com/showthread.p...hlight=MSD_DIS

MSD 6A info: http://www.msdignition.com/ignition_4_6200.htm

MSD D6+ info: http://www.msdignition.com/ignition_18_6520.htm

MSD D6+ instructions: http://www.msdignition.com/pdf/frm23775_6520.pdf

Hmmmm, very interesting. Some has had to have done it already......anyone?

Well there are only 3 know people who have even done the MSD_DIS setup. Myself one other guy on here and a guy with a tryumph 13b. I was hoping that there might be someone on here that had more muscle car experiance than I that might've plaied around with both the 6A and the D6+ and could offer some first hand experiance...

cough...

I can tell you that my Tuner - Crispeed prefers the 6A/6AL's on the rotaries because they are more robust, and have better dwell than the DIS box's.

Money being no object - I opted for 3 6AL's with my Haltech setup.

MSD customer service sucks. I sent them an email 2 weeks ago then again on tuesday and still no response. Can you believe that crap. My main question is weather the digy6 would charge the DIS coil better. Since it does 135 millijoules as opposed to 115, and 55 volts primary as opposed to 480.

So I thought I'd bump this since I hate wasted bandwidth. I got into a pretty good conversation with some muscle car tuners today. Turns out the next big thing is the Mallory VIA ignition. It is better than the MSD 6A in every way, and it's cheaper. Plus it's digital instead of analog. that means it uses less power and is much more accurate. You can get them on Jegs for $130, so I'm going to pick one up for my next CDDFIS-DIS. It's not as good as the D6+, but Mallory has a model similar to the d6+ that is yet again better and cheaper than MSD's equivalant. Last year Mallory ran this promo:

Wanted Dead Or Alive - Mallory Ignition has put a bounty on MSDs head, so to speak. Mallory's latest promo promises to pay a $25.00 - $75.00 Bounty if a customer buys a new Mallory Digital Ignition Box (6852M, 6853M or 685) between April 1st, 2007 and December 31st, 2007, and sends the original purchase receipt and the bar code label from the Mallory package, along with their Dead or Alive MSD ignition box, (postage prepaid) to: Mallory Ignition - MSD Bounty, ****************

In return, Mallory will send a a $25.00 - $75.00 Bounty check, depending on MSD box returned: $25.00 Bounty for MSD 6200 & 6300, $50.00 Bounty for MSD 6320 & 6420, or $75.00 Bounty for MSD 6350, 6462 & 6520.

Compared side by side, the Mallory 6A, 6AL, and 6AL2 have the same wire color coding and mounting pattern as MSDs 6A and 6AL analog ignitions for simple replacement. However, the Mallory 6AL Ignition has 1 stage of rev-limiting that requires NO chips for adjustment unlike the MSD 6AL that requires extra-cost chips for specific RPM settings. The Mallory 6A, 6AL and 6AL2 ignitions also have 19% more spark energy, 10% more primary output voltage and 40% lower energy draw than comparable MSD boxes for maximum performance and reliability.

Here is a derect com[pairison of the Mallory to the MSD as well FYI it's a PDF:
http://www.malloryracing.com/pdf/Mal...arisonData.pdf

I'm not promoting Mallory I'm just letting people know that there are options besides MSD. Mallory, Crane, Jacobs, and Summit now has a $100 digital box... I think I'm going to get a Mallory boxand Crane coils. I'll do before and after dyno runs as well.

i was thinking about trying out the summit digital ignition box to see how it does... i havent heard anything about them, but they seem to have better numbers then the msd and jacobs boxes. Plus for a little extra $ you can get the one with the built in rev limiter and still be cheaper then the msd boxes

Msd Super Thread!!!
 

NOTE: This is a leading discussion only Trailing is "stockish."

Well I'm trying to rethink the coil situation. Before I was using the MSD DIS coil, but I think there has to be a better solution. The best idea I had was to use 2 VI-A boxes shareing the magnetic pickup signal and letting each box have it's own coil. I know that using 2 coils on one box will split the voltage weather or not I ran them in parallel or in a series. That was what led me to the DIS coil. the only thing I didn't like about the DIS coil was the mountaing and it kind of had to be jimmie rigged. I honestly have no idea how the DIS coils work and how to hook it up all I know is no matter where I plugged in the wires it ran. So that's why I'm considering a different solution. My idea of using 2 boxes and 2 coils for the leading would in theory allow both boxes and coils to operate at full capasity. But, my consern is splitting the magnetic pick up signal to two boxes. Would or could that cause an issue? IDEAS!

Two Msd 6AL's
 

I have my leading Mag pickup running two msd 6Al boxes and it works great. I'm pretty sure it will work for you as well. I just mounted my #1 leading coil on the side close to the plug.
It fired up right away and has a way better idle.
Trailing was left stock other than msd coil and wires.

UPDATE: Upon further research the Crane Hi-6 puts 1,200 Millajules of spark out put. While every other box only does 125-135 MJ. LOLZ I want a crane box now. I just don't know if I want a crane cams sticker under my hool LOL!

WOW! that a huge diffrence.
I wonder how much better it performs and the price diffrence.

The Crane Hi-6 is right around $300 new a MSD D6ALis $400 new and the Mallory VI-AL is $150

Well what ever you end up buying this kind of setup works well for me so far.
Not too too much testing before I started tearing into the motor though...

Where is Jeff20B when you need him. lol

I may be wrong, but seeing how the specs are identical, I think the Summit box is a Mallory 6AL with a Summit sticker on it.

I was thinking the same thing.

Has anyone ever ran a Crane box? Rotary or pissedon?

Hmmm this is very useful information for me.. was considering upgrading my stock ignition coils to MSD A6L's and figure a way to still use my Dizzy...

Let me know if anyone has done this before and I am really interested in that Mallory system now...

Before I set up the direct fire setup I had two blaster 2 coils hooked up in the stock way then I hooked up 1 MSD box to the leading by taking the wires off the coil and wiring them to the small red and white wire on the MSD box then the small orange and black wire went to the coil and it worked great. gave me a much smoother idle and easier cold starting.
I do recommend to try and go dirct fire though it helped with both idle and cold start up even more.
Direct fire made extreme cold start up (-20C and lower) way better.

I have been looking at the summit box as well. Some good hard input it needed in this thread. I need stronger spark for my 12a turbo. I dont think the the fc coil is doing it!

Anyone know more about millajules of spark, and if upgrading from my MSD box to the crane Hi-6 Would be worth the investment. My MSD Box has been in 13 cars now and is 10 years old. I'm looking for an excuse to upgrade.

1985 Turbocharged Mazda RX-7 GSL-SE "Cosmo" 13B-RE

here you go check this link out i hope it works out for you. oh yeah i am looking for a video that i came across with thcat set up on a 13b the key words are above. he has some bad ass mods.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/msd-coil-set-up-758025/

I'm not having coil issues and right now I'm runnign a stock FC coil anyway. I.m trying to find out if people have any experience with ignitions other than MSD

i need help running a turbo I want to run 4 msd blaster 3's turbo 2 crank angle I already have 4 msd 6al laying around as well as the msd blaster coils...wil this work will it run and how do i go about wiring this?

If not that way Can i runn two blaster ss coils and 3 HVC-2 coils and the three 6AL'S

will that work?

you can't use blaster 3's with 6 series ignitions... the blaster 3's are only good with the 7 series and up.

I ran the two blasters and two 6al's with the dizzy on my 13b ran really great...But now i need to upgrade and get the more powerful spark for the turbo setup...could you pm me some info

Just lock the dizzy and set your timming to 10* BTDC and run both through the cap, and you'll be good. Or if you want direct fire on the leading do that with a FC coil and run the trailing through the cap. Either way lock the dizzy and set timming to 10*BTDC and you should be good.

Okkkkaaaaaaaaaaay! So my MSD 6A finally died... I'm on the market for a new ignition box. Does anyone on here know anything about millajules of spark and is the Crane box worth the extra money?? If not I might just go with the Mallory box this time around. Does anyone have any experience or know ony info on other ignition boxes besides MSD. Specially the Mallory or the Crane boxes.

Used to have a 1990 mustang w/ 351 windsor, .30 over, forged pistons, ported and polished heads, harland sharp roller rockers, Comp cams magnum grind 280/512 cam, holley 750, msd 6a, msd billet distributor, msd wires, msd blaster coil, ford 9" w/ 3.70 gears and moser axles, ford racing T-5, ford racing suspension, 10.5" slotted rotors with ceramic pads, 6 point cage, all the good stuff. The ignition never failed me. That thing would start on the first crank every time, and ran like a raped ape. I know for a fact that the msd setup is worth it.

I've heard alot more good reviews about the mallory then the crane. Haven't had either myself. Mallory has always been a ignition manufacturer, crane is known for their cams (atleast in the muscle car world). Just compare and contrast, then go with your gut instinct.

teddyrx2, if you decide to go with something more powerful, would you consider selling me those blasters? Not looking to spend alot, but if your upgrading, maybe we could negotiate.

K so I confirmed that the Summit boxes are made by mallory, but right now the Mallory is cheaper. Soooooo.
http://www.summitracing.com/streetan...A82B40E3971%7D

Borrowed from a very old crane page. Great info here:

The Ignition Process
The ignition process is key to the operation of internal combustion engines. Four-cycle engines require external combustion, and this is accomplished by discharging electrical energy through a spark gap. Heat transfer and gas ionisation (splitting apart of gas molecules) caused by the spark discharge initiates a flame kernel. The flame kernel then grows into a flame front that spreads through the combustion chamber. The stages of a spark discharge include breakdown, arc, and glow discharges.

Breakdown
Most engines require nearly 12,000 volts to fire the spark gap. When this voltage level is reached, a very high current flows for an almost immeasurably short period of time, as energy stored in the capacitance of the coil, secondary wiring, and spark plug is rapidly discharged. Because the breakdown phase is so short, it accounts for only a small percentage of the total ignition energy.

Arc Discharge
The breakdown phase is followed by an arc discharge. An arc dis*charge requires a considerable current flowing in the gap, at least 0.2 amps. During the arc phase, the voltage across the gap drops to a few hundred volts. An arc discharge is very visible and high levels of energy are transferred to the flame kernel near the centre of the spark gap, as shown here.

Glow Discharge
A glow discharge is less intense. A good analogy to arc versus glow discharge is comparing an arc welder to a fluorescent lamp. Much of the energy in the glow discharge is lost heating the electrodes as shown here. Most ignition systems start with a breakdown and arc phase and then end with a glow discharge as the stored energy is used up. The trick is to maximize the duration of the arc discharge, since this transfers the most energy to the flame kernel.

Terms and Variables Used to Rate ignition Systems
Peak Gap Current - the maximum current flowing during arc or glow discharge. A critical measure of ignition performance.

Total Spark Duration - how long the spark will last. Duration is usually measured in microseconds. Long spark duration reduces lean surge at part throttle.

Available Voltage - also referred to as the maximum open gap voltage. Measured by opening the gap until no spark occurs. Usually much higher than the required firing voltage under actual operating conditions.

Millijoules Ignition Energy - The millijoule is a measurement of ignition energy. (Energy = voltage x current x time.) Primary energy is the stored energy in the ignition system. Only a fraction of this energy is delivered to the flame kernel during the spark discharge.

Cyclical Variation - the technical term for misfiring. Variations in engine output from cylinder to cylinder firing caused by differences in the rate of pressure rise after combustion initiation. An unstable flame front can increase cyclical variation. High output ignition systems with a long arc duration reduce cyclical variation by promoting rapid growth of the flame kernel into a stable flame front.

Selecting The Right Ignition System
Selection of an appropriate ignition system can unlock power by reduc*ing cyclical variation. Cyclical varia*tion ("misfire") can be reduced by ensuring a stable flame front. How can we ensure a stable flame front? First, available voltage must exceed required firing voltage so that the spark will fire across the gap. In conventional inductive ignition systems, available voltage drops off at high RPM. At some point, the engine will start to exhibit gross misfires and power loss. Even if the spark gap has been fired, the system must transfer enough energy to ensure that the flame kernel will rapidly grow and spread. A high gap current, sufficient to cause an arc discharge and a long spark duration, will ensure a stable, spreading flame front.

Our tests have shown that most race engines with power output rated between 500 to 1,000hp require at least 0.3 amps peak gap current and a minimum 100-150 microseconds spark duration. Engines in excess of 1,000hp may require a peak gap current of 0.5-1.5 amps and a spark duration of 300-500 microseconds.

For street engines, a long spark duration is critical. Cruising at part throttle under high manifold vacuum conditions can result in pockets of lean mixture within the combustion chamber. Insufficient spark duration will result in misfires, lean surges, increases in emissions and loss of fuel economy. At least 0.05 amps peak gap current and 1000 microseconds spark duration is required.

Types of Ignition Systems
1. Inductive Discharge Systems
Most original equipment (OE) ignitions are inductive discharge systems derived from Charles Kettering's principle first described in 1908. Inductive discharge systems operate on the principle of energy storage in the coil primary windings. A typical inductive discharge ignition system is shown here. When the switching device (points in early systems, transistors in electronic systems) closes, battery voltage is applied across the coil primary and current builds up. Stored energy is proportional to the coil inductance times the square of the current. By its nature, an inductor tries to maintain a constant current flow. When the switching device opens, the primary current flow is disrupted and current flow transfers to the secondary, firing the spark gap until the stored energy is used up.

Points systems and early electronic systems use ballast resistors to limit current. Later systems limit the current electronically via the transistor switch.

A disadvantage of inductive systems is that energy falls off at high RPM because insufficient time exists to charge the coil. OE systems are generally good up to about 5,000 RPM. Crane's FireBall high output inductive discharge systems such as the Hl-6S, XR700 and XR3000 extend the RPM range upwards of 8,000 RPM.

Most electronic inductive ignition systems have a peak gap current of about 0.04-0.06 amps. This gap current is sufficient for street and some race applications. It is insufficient to cause the long arc discharge required for peak performance in high-output race engine applications.

2. Capacitive Discharge Ignition
Capacitive discharge (CD) systems are widely used in racing and overcome the limitations of inductive systems at high RPM. A typical Crane multi-spark CD system is shown here. A capacitor is charged up to about 475 volts. The stored energy is proportional to the capacitance times the square of the voltage. An electronic switching device such as an IGBT (insulated gate bipolar transistor) then discharges this stored energy into the coil primary. A high voltage pulse appears on the coil secondary and fires the spark gap. CD systems are more complex and expensive than conventional inductive discharge systems because a high voltage power supply is required to charge the capacitor.

Single spark CD systems create high gap current well above 0.2 amps but are characterized by a short spark duration of 150-500 microseconds. The high gap current can create a true arc discharge ideal for high RPM race engines running rich mixtures. CD systems can help reduce plug fouling. CD systems can also operate at engine speeds in excess of 10,000 RPM without energy loss, but the short spark duration can create driveability problems on the street, such as lean surge at part throttle. Thus the need for multiple spark technology

Multiple spark technology is required for street CD systems. Multiple spark CD systems have a specially designed power supply that quickly recharges the storage capacitor allowing multiple sparks to be fired from cranking speed up to 3,000 RPM.

Above 3,000 RPM all multiple spark systems revert back to a single spark. The multiple spark fired at the lower RPM levels typical of street driving results in a much longer effective spark duration. The benefits include quicker cold weather starting, smoother idle, and reduced lean surge during cruise. The Crane Hl-6 multiple spark CD system delivers up to 12 sparks per sequence.

3. Resonant Converter Ignition
State-of-the-art resonant converter technology drives the coil primary with high voltage alternating current. The Crane Hl-8 resonant converter system is shown here. There is no storage capacitor that needs to be recharged between cylinders firing. Resonant converter systems can theoretically generate a continuous spark. The spark duration is limited only by practical considerations such as cross firing within the distributor. The HI-8 resonant converter ignition system achieves a peak gap current in excess of 1 .5 amps with a spark duration of 450 microseconds. Big block engines with highly turbulent combustion chambers and engines running alcohol have gained 10-15hp based on documented dyno tests with resonant converter ignitions such as the FireBall Hl-8.

Coil Selection
The ignition coil plays a key role in determining system performance. Original equipment coils usually have a turns ratio of 100 secondary turns to every primary turn. Secondary current, which is the same as the spark gap current, is about 1/100 the peak primary current. Available secondary voltage is 100 times the primary voltage. Some aftermarket coils have higher turns ratios to increase the available voltage. However, the available voltage need only exceed the required firing voltage, which is generally not more than 12,000-15,000 volts. Tests have shown that most engines running plug gap sizes around 1.1mm are better off with a lower turns ratio, in the 60:1 range. This gives a considerable increase in gap current.

Coil construction also effects ignition energy. Early coil designs were based on an open core and packaged in a can filled with oil. Newer designs use a transformer style construction with a closed core in the shape of an "E", hence the name "E" core coils. The closed core results in a closed magnetic path and less "leakage" of magnetic flux. The technical term is leakage inductance and the effect is shown here. Less leakage inductance results in more energy transfer to the spark gap.

The Voltage Myth
Nothing has caused more confusion than the issue of available voltage. Some ignition brands have compromised their ignition system designs so that they can claim very high available voltage figures, such as 40,000 or even 50,000 volts (40 or 50kV). Actual tests on race engines show that the required firing voltage is in the 8,000 to 12,000 volt range at wide open throttle and high RPM. Starting a cold engine is the worst case and may require as much as 15,000 volts to fire the plugs. Once the spark is fired, the arc sustaining voltage drops to a very low value - no more than a few hundred volts.

For a given ignition system, available voltage and spark gap current are inversely proportional. An ignition system designed to provide a high available voltage will sacrifice gap current. The high available voltage figure may look impressive, but actual engine performance suffers.

The Energy Paradox
Energy is the product of voltage, current, and time. The electric company sends us a bill based on the energy we use. In this case, the voltage stays constant. If we turn on more lights or leave them on longer, the energy consumed goes up and so does our bill. Things are not that simple with ignition systems. The problem is with the voltage across the spark gap. Here we are talking about the arc sustaining voltage once the spark has started. The arc phenomenon is very non-linear. If the gap current is low, as in an OE inductive ignition, the gases in the gap will be weakly ionised (glow discharge). The resistance across the gap remains high, causing a high voltage of about 1,000 volts and a high calculated energy figure. Race ignition systems with high gap current levels cause the gases to become strongly ionised (arc discharge). The resistance across the spark gap becomes very low and the voltage may drop to as low as 150 volts. This leads to the paradox that the calculated energy figure for the race ignition may be less than that of the OE system. Millijoules energy figures can be misleading.

Comparisons of gap current and spark duration are more useful and tend to correlate more closely with observed engine performance. Because of the paradox of low spark gap energy for race ignition systems, vendors often give primary energy specifications. For CD systems this is the energy stored in the capacitor. Only a fraction of this energy ever reaches the spark gap. Since factors such as coil turns ratio, leakage inductance, winding and plug wire resistance all effect the energy transfer, primary energy figures are almost meaningless. Again, gap current and spark duration provide a more accurate basis of comparison between ignition systems, since these parameters directly affect flame kernel growth.

That's a lot of good info there. Thanks for posting!

So I bought the Mallory HyFire VI-A. It should be here today, I'll post results.

Let us know how the exhaust note changes, if at all.

I just got it. It's so pretty, all new and shiny. I decided on the Mallory because of Crane's own write up. They said the important thing was the ignitions ability to quickly recharge the coil and it's maximum voltage across the sparkplug. The mallory had better numbers. Although in millajoules of spark the Crane was ten fold their competitiors they themselves said the numbers can be misleading. From everything I've read Ignition to ignition they won't make that much of a difference that it comes down to the coil. The reason big HP guys run huge 7 and 8 series ignitions is because the need to be able to power the bigger coils. It all depends on the coil an dthe ignition box helps the coil do it's job better. I hope the FC coil is up to the task.

The FC coil has a low primary resistance so it should charge pretty fast.

I installed it on my lunch. It took me 15 minutes since it is the exact same size as the MSD and all the plugs and wires are the exact same color so it literally plugged right in.

Driving Impressions:
Idle went from 900 rpm to 1100 RPM. I was able to lower the idle back down to 900 rpm and take fuel out at idle without suffering the smooth idle.
Greatly improved cruise. There are very few lean surges now.
Exhaust note is the same considering all I did was replace my MSD with the Mallory.

Worth the money?
Fluck yes!
It's cheaper than a MSD and the improved cruise and throttle response is more than worth the trouble. And, it's fugging cheaper than a MSD!! and it either beats it or is equal in every catagory $139.95 on summit right now with a $25 dollar rebate if you buy it before 07/31.
I think I'll send my MSD into them to have it refurbished. I guess it's like $50 then I'll run it through the cap for the trailing.

Side by side
https://static.summitracing.com/glob...msd-6200_m.jpghttps://static.summitracing.com/glob...-6852m_w_m.jpg

Brand
MSD Ignition----------------------------Mallory

Product Line
MSD 6A CD Ignitions------------------Mallory HyFire VI-A Digital CD Ignitions

Part #
MSD-6200 ----------------------------MAA-6852M

Price
$184.40--------------------------------$139.95

Description
Ignition Box, 6A, --------------------Ignition Box, HyFire VI-A,
Analog,---------------------------------Digital,
Capacitive Discharge,--------------- Capacitive Discharge,
Universal,----------------------------- Universal,


CARB EO Number
D-40-33--------------------------------None

CD Voltage Output to Coil
460-480 V-------------------------------520 V

Circuitry
Analog----------------------------------Digital

Coil Included
No--------------------------------------No

Current Draw
1 amp per 1,000 rpm----------------0.6 amps per 1,000 rpm


Data Acquisition
No--------------------------------------No

Height (in)
2.250 in.---------------------------- 2.750 in.

Ignition Box Color
Red---------------------------------- Red

Ignition Box Output
Capacitive discharge-------------Capacitive discharge

Length (in)
8.000 in.-----------------------------8.000 in.


Maximum Operating Voltage
18 V--------------------------------- 16 V

Minimum Operating Voltage
12 V--------------------------------- 8 V

Notes
Even-fire only on V6.--------------If this ignition is used for racing the warranty is 90 days.

Quantity
Sold individually.------------------ Sold individually.

Rev Limiter
No-----------------------------------No


Spark Output (millijoules)
115 Millijoules--------------------135 Millijoules

Timing Retard
None--------------------------------None

Warranty
One-year warranty--------------One-year warranty

Width (in)
3.500 in.---------------------------3.500 in.

Slightly off subject, but these mallory toys sound interesting...

What would be a good box for a NA S4/S5 13B?

You're actualy completely on subject. Just get the one I got and install it according to the MSD writeup on fc3s.com as I said before the wires are exactly the same as the MSD. So check this out I can get the car to Idle smooth at 600 Rpm. Lol this box is awesome.
Jeff do you know the specs on the FC coil? Specifically resistance and voltage.

Sorry, I wish I did as I'll be using two on the 4 rotor with a GM HEI each. Not sure whether I need to include the ballast resistor and all that.

So I swapped the tach signal for my shift light to the Mallory and it does the same thing the MSD did, so I think my MSD was fine. I guess I'll throw it on the trailing. I did notice one thing though. Both the Mallory and MSD run really hot with the FC coil. The FC coil and both the boxes are too hot to touch. I'd say they get to about 175* I wonder if the FC coil is bad or if the resiatance is much lower or higher than we thought.
https://www.rx7club.com/showthread.p...highlight=coil

Hyper,

Are you running the 2nd gen ballast resistor or just directly to the coil (+/-) terminals? Going from memory, the 2nd gen coil is about 0.8 Ohm and the ballast is 0.35 Ohm (sure about this value)..so a total of 1.15 Ohms or so with the ballast. 1st gen coils are in the 1.35 Ohm range. If you are not using the ballast, you should probably add it. The Mallory/MSD will be happier and live longer with the cooler operation.

Well all the FSM says is that it should be below 1 Ohm, but if it's too low it could be bad too. Huummmmmm Well see. I'm not running th ballist. Maybe I should try it out.

Try the ballast. Power (W) = V^2/R. Voltage is fixed, so lower resistance (R) means more power (heat) dissipated. I believe my 2nd gen coil was 0.8 Ohm, but the ballast will add another 0.35 Ohm to that.

Does the Mallory/MSD list a spec for minimum coil resistance that it can be used with?

So I've been running FC leading plugs cause I had a bunch sitting around. i decided it was time for a change and I threw in soe B7ES plugs I had sitting around for a while and I tell you what. The car felt like it was only making 75whp. LOL! I don't think the Mallory likes resistorless plugs. I have no Idea why it wouldn't work. It makes no sinse to me but the car took about a 1/4 mile to get to 60... I threw the FC plugs back in and I was doing donuts again. Who knows...