Does MSD make power?

[bevans]

I run in a series (vintage road racing) that doesn't allow Multiple Spark Discharge systems. Electronic ignition switching a normal coil is OK. We always get guys who think their engine can't run without their MSD, or who make arguments that it just helps with plug fouling in the pits and makes no difference on the track.

When I've seen dyno tests of typical motors that run fine without MSD, adding an MSD hasn't made much difference. I put it down to the theory that at high rpm (say 7K plus) there aren't many multiple sparks, and if you don't need the high voltage to fire the plugs in the first place, you won't actually develop the 50KV or whatever the monster coil can develop...

What is the real world advantage of an MSD system in a world of 4 cylinder 1960's and 1970's racing engines? Can you develop an engine with MSD in a different direction than one without, and make more power? Carbs are usually Weber DCOE's, compression is up to about 13:1, combustion and flow is usually 20 years old so not developed to the Nth degree.

Thanks for any and all input.

Brian

[Ron E]

Offering a "bump" 'till somebody who knows sumptin' shows up...
My understanding is, a MSD will recover power lost due to an inadequate ignition system. So, it doesn't "make power", unless your current system is costing you power.

The multi-sparks turn into a single long-duration spark at high RPM, or so I'm told.

On a tune with, or without a MSD, We once ran a bracket car in pre-MSD times. It was a 440 mopar (hard to get a worse spark-plug location). If it was leaned down to give the best ET, it shot ducks all the way down the track.(embarrassing). To make the motor run smooth down the track required fattening up the carb to the point of running about a tenth slower. When switched to a MSD, it would run at the leaner/faster jetting, without popping.
DISCLAIMER: It was a motor made out of old parts with a Holley that was far from fresh, and we basically were too ignorant at the time to operate a race car. But, in this case, the tune-up was dependent on the MSD.

[bobqzzi]

I am greatly interested in this subject.

I can't see how once you get beyond the spark neccessary to light the fire it could make any difference- BUT I know the domestic guys swear by them, and the extreme engines use boxes with enough juice to be welders. I also know that many extremely competent people on this board like and use these systems, so I can only assume there must be a good reason why.

My experience is with 4 cylinder European stuff and I have never seen an aftermarket ignition make any more power than the stock Bosch stuff. Even on a 700hp 4 cylinder, the stock coil on plug was fine.

The one domestic engine I have experience with is a Cosworth Vega. It made about 270 hp at 8600. The stock HEI would work fine for a little bit, but then the module would overheat and it would stop. We replaced it with a stock Bosch electronic distributor from a Rabbit and it made the same power, but didn't quit 3/4 of the way into the race. For packaging reasons, we then went to an electromotive crank triggered system- still made the same power

I'd say that in the OPs situation, that a compent "standard" ignition should be just fine.

[Unkl Ian]

My understanding is, a MSD will recover power lost due to an inadequate ignition system. So, it doesn't "make power", unless your current system is costing you power.

We ran into that on a 2 liter Hart motor,in the Mid '80s,
the previous POS ignition box seriously retarded timing above 6000.

Hard to make power at 10,000 when the timing retards 20+ degrees.
Hard to start the motor when you have to dial in a bunch of extra advance so that the timing is correct above 6,000.

The more American hot rod parts we bolted on,the better it ran.

I'm sure there are ways to make a motor run decent without an MSD.

[Metrobilly]

Brian,

I race old Volvo's in the SCCA. I use a MSD 6AL for two reasons. First the car starts more reliably in cold weather. I have missed a couple track sessions over the years because I couldn't the the car started on a cold damp morning with a points baased ignition. The MAD makes a big difference on cold days.

Second it is a convenient way to add a rev limiter. In one of my cars the rules require a stock distributor housing and I use a Pertronics ignitor io trigger the MSD which provides slightly less spark scatter than any of my old distributors can provide with points and a cleaner trigger to the MSD.

On a couple occasions I had the MSD with a rev limiter make the car run worse. I attributed it to points bounce or vibration or spark scatter induced poor triggering signal to the MSD. Using a magnetic or optical trigger in the distributor or on the front crank pulley provides cleaner signal to the MSD unit.

I don't know if it makes more power.

My brother also uses a MSD 6A triggerd by a magnetic pickup on the front crank pulley in his SCCA F/P Spitfire. He can bypass the MSD and go to a points ignition with the flip of a switch. He says it runs better on the track with the MSD.

Charlie

[ProPower engines]

Back in the early 80's I helped a local guy with a circle track car. It had a 307 engine 2bbl restricted engine and a stock single point dist. If we tried to lean it out to get a better burn it would miss. I put in a stock HEI dist. and used a 4cyl. Vega ign. module and external coil and the thing ran smoother and the car picked up 2 10ths on a 4/10 mile track. Never changed anything else just the ignition. I believe that more power is gained by any improvement in getting a more complete burn in the cyl. cause the more that burns in the cyl. the more HP can result....

[1989TransAm]

I have one piece of experience with a MSD 6A. During chasis dyno pulls a few years ago we did back to back test on the Chevy 350 V8. Don't remember the exact horsepower but the car put down about 330rwhp. Took off the MSD 6A and the car made 328RWHP. Hooked back up the MSD 6A and the horsepower went back up to 300rwhp. This is primarily a street car and the MSD finally went bad after a number of years. I have left it off. Not worth the 2 horsepower over reliability.

[automotive breath]

The primary benefit of a capacitive discharge ignition is the ability supply
a higher voltage spark to the mixture inside the combustion chamber to
maximize burn efficiency. One way to get a larger spark is to increase the
spark plug gap. Increasing the gap distance increases the voltage necessary
to ionize the mixture between the gap. In addition resistance of the air/fuel
mixture increases with cylinder pressure requiring even higher voltage to
spark across the plug.

A CD ignition delivers the higher voltage required by the increased spark
plug gap size and higher cylinder pressure. The actual need for the increased
secondary voltage depends on the in-cylinder conditions at the time.

[JCR]

We always get guys who think their engine can't run without their MSD, or who make arguments that it just helps with plug fouling in the pits and makes no difference on the track.

Its a case of "Monkey See, Monkey Do". Those boxes (MSD,Crane,Pertronix, etc.) are band aids for some OEM systems. The MSD boxes fire multiple sparks below 3k RPM and go to a single spark above that. MSD makes both inductive (MSD 5) and cd boxes. The high end doesn't even bother with these. They are using crank fired single coil per cylinder. You may find these threads of interests.
http://efi101.com/forum/viewtopic.php?t=390
http://efi101.com/forum/viewtopic.php?t=1978

[#84Dave]

The situation with many ignition add-on's is the 'adders' just throw the box at the engine and don't experiment. The wider the gap at the plug, the better the initial kernal development. The better the kernal, the less the ignition delay, in most cases, with decent chamber design. Less ignition delay, less ignition lead needed to put cylinder peak pressure where it needs to be (~50% mass-fraction burn). Less ignition lead, less negative work, more torque/HP. I bought my first MSD in 1974. Have used them since. With up to .065" plug gap. Work with the box, it'll work for you.
Dave

[PackardV8]

Greetings, All,

Agreed, on a good, strong ignition, an even stronger one won't make any more horsepower. If every component of a distributor ignition is the best money can buy, and is in perfect condition, then the MSD doesn't add horsepower.

FWIW, I hate distributors in any shape, form or fashion. Even the best ones scatter spark timing more than will a crank trigger. The Cup car guys spend literally thousands of dollars on one distributor, shimming, running in the drive gear, tweeking the triggers. At least, they don't have the camshaft also driving the oil pump off the distributor. Using a high volume and/or a high pressure pump plays hell with the spark on some engines - Fords and big block Mopars seem to be the worst for scatter.

On the older cars in classes which require the distributor to be retained, I have degreed the aluminum flywheel and installed magnets to trigger a sensor hidden where it couldn't be seen without pulling the engine. The spark box has to be similarly inconspicuous. The distributor then only parcel out the sparks. There is enough overlap of the distributor terminals and the rotor tip that it works OK. Still not as good as coil-on-plug, but better than using the distributor for timing the spark.

thnx, jack vines

[Ed-vancedEngines]

Does MSD make power?

No.

Neither does a big volume fuel pump either.

A stronger ignition system can allow more power to be made if another lower poweed ignition is not fully doing it's job. Most don't.

It would be amazing to learn in the course of one race just how many times a random cylinder did not have complete ignition.

Will a good MSD ignition system that is compatable with the engine's needs allow more power to be made? In my opinion, absolutely.

The ignition system's job is to get the flame ignited. IF there are hostle conditions in the fire chamber area it will take a stronger initial spark to get it to even ignite. The Digital 7 series of ignitions creates a major spark that usually fires under the most extreme conditions. Exceptions are with SEvere bosted Blown Alcohol and Blown Fuel the Mag 44 system, from MSD is said to provide a more consistend more powerful spark.

In the earlier daus of the MUlti-Spark Discharge from MSD we had jumper connectiuons on the ignition coil, so we could quickly convert back to eliminating the MSD Box from the system. We had first hand proof that at idle speeds there was an idle rpm improvement when the MSD was in effect.

The only reason why the Multi-spark is better and only works at low and moderately high rpm is becuase of the time limitations for each spark with crankshaft revelutions. It gets to the point that before the ignition can fire the plug more than the initial spark firing, the piston is moved to far for any additional fire would be detrimental.

Comparing the intensity of any factory ignitiion system, with no Capacitive Duscharge box, to using a MSD, Crane, Mallory etc. is ludricoulas. The Aftermarket Capacitive Discharge MUlti-Spark ignition systems serve in much more useful functions than just another style of ignitiion module.

Ed

[Ron C.]

The tech manuals for MSD state the multi-spark stops at 3000 rpm. One of the MSD tech reps at MSD told me it's actually about 2800 RPM. Primarly it's intended to keep the plugs cleaner at low RPM's.

Blessings........Ron .

[n2omike]

Hmmm...

Haven't heard much about those capacitive discharge Nology spark plug wires, lately. If I remember right, they were even being used in Fuel cars for a while...

Anybody know much about those? I know a few people who have used them on motorcycles and liked them. (MUCH more affordable for a single cylinder dirt bike)

I wouldn't hijack, but it seems the question about MSD has been answered.

Thanks

[Jerry Poole]

Will a MSD unit, (6 or 7 series), control total advance thru its function or will the distributor need to calibrated on a distributor machine to achieve say 28-32 degrees total advance? The distributor we have to use must use points. The postings here have helped me better understand exactly what the MSD units do. Was never sure about if they controlled total advance. Will MSD part number 8981, programmable timing computor, work with a points type distrutor or is just for electronic distributors. Thanks for any input