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L28E,
F54 block w/flat top pistons, N47 head and 76 N47 EFI manifold (bored to gasket edges and mated to a 240SX throttle body) after market cold air intake (custom, and no, not PVC lol), MSA header mated to 2.5" exhaust and turbo II muffler with no catalyst).

I am going to be running 10:1, approximately and running on 91 octane.
I will be using NGK platinum plugs with 8.5 mm plug wires.

what is the best coil for the money as a replacement for the stock coil?

Thank you,
Nick
 

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Nissan Z31T Stock Coil

Hottest Coil Nissan Made, and far superior in build quality and longevity than almost all "aftermarket" crap you can buy for a lot more money.
Plus, the added benefit of plug-n-play with the power transistor, and available in junkyards for about $2 makes it a combination that is hared to beat...
 

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Hey Tony D, you think a Z31 Turbo coil would fire up my engine fine? I'm needing some ideas on how I'm going to manage the fuel and all in this turbo beast I'm building. I like the look of the SDS with the coil packs so I don't have a distributor, but it costs quite a bit more than a Megasquirt, even already assembled by someone ($500 last time I checked). What do you suggest to run a monster? I want a standalone system, not some modified Z31 ECU or anything like that. I could go either way, I just don't know what complete package I need. Whether some systems need a coil and some don't or whatever...I am TOTALLY clueless as to ignition stuff for high power turbos and standalones.
 

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The "coil packs" isn't the way to go, the other "E" system uses an MSD ignition box which makes a lot more spark energy. There is more to "hot spark" than the coil.
 

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welll....

<edit> this was supposed to be in response to matt300's last question above, I must've clicked on the next topic when my cursor passed over it...<edit>
it all depends on the cirucitry that controls the coil.
The TEC2 used some neat circuitry to monitor the previous firing of that cylinder to allow charging it to that point, then moving on, allowing far less amperage load on the electrical system for the same power for conventional "blast the **** out of it boxes".
I am not sure if the SDS coil packs use that kind of circuitry.
The Z31T coil seems to work fine on my Megasquirt-n-Spark setup on a 260ZT.

There's a lot more to the system than the hottest coil, or having a coil for each cylinder, etc etc etc...

By monster what do you mean? Steve Mitchell has over 600HP and 730 ft-lbs of torque on his Z31T, and it only uses one coil.

So "Conventional Standalone Wisdom" really isn't a stamp of approval for all applications. But again, he's using a Z31 Remap, too....

Confused? Good! There are a LOT of options, you have to determine for yourself what you think will be the best for you, and your skills.

Every project needs a starting point, and that should be some quantifiable figures of performance you want: 0-60 in 3.5 seconds, 1/4 mile in the low 10's, top speed of 180mph minimum. THEN you figure out what you need to go there, and build accordingly.

Too many people start with "I WANT THIS MUCH HP" and then get dissapointed with a car they can't drive, or are otherwise unhappy with.

Start with goals, and you may find you goals are reachable without building a monster. And if that's the case, think how much MONEY you have SAVED!



Post Edited (Oct 17, 11:27pm)
 

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Well Tony, as far as the actual motor itself, it will be capable of way more hp than I want. I'm wanting about 325-350 at the crank, of course I know I can up or down it by hitting some buttons on the fuel system, and the boost controller and all that, but I think 300 or so to the wheels will scare the piss outta me, so I'll keep it at a reasonable level. I know the Megasquirt will be able to provide fuel for that amount of power, I just don't know what ELSE I need in the Megasquirt n Spark kit. Like, the hot Z31T coil, if I need a certain type of distributor, etc. If someone could give me a list of what I need, I'll know what to go out and buy. I know what to buy as far as the actual fuel delivery, turbo, intake, etc...just don't know jack **** about ignition.
 

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Yes all you need is the one coil...

<http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=28495>

Best post ever! check out the diagram for the electrical system, one coil and a hei module.

Mat.
 

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Check out...

Moby the Van's Sticky over at Hybrid Z under the Turbocharged and Supercharged forum.
That should give you all you need. My understanding of the Z31 CAS in the distributor is similar to the 280Z, so you whould be set for the triggering impulses with a hookup identical to the 280ZXT.

That sticky lays it out for you, and basically you replace your power transistor with a GM HEI module and let the ECU (Megasquirt) run the ignition map you program into it.

It's pretty straightforward. And theZ31 has a better set of connectors on it for electrics, to boot.

You will have to do the wiring, and maybe experiment, but the resistors and diagrams on Mobys' Sticky have been dead on for those who have used it.

After that, get the right size injectors.

Good Luck.
 

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I personally would only run multi coils in cases where the car is going full sequential on the EFI and running very large injectors. Even most "monsters" can get away with a single coil. Back it up with a MSD 6A ignition box and you should be good.
 

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I agree.....

That is very true.... If you think about it, a nitro motor runs two dist, and two coils, and it does rather well. Pro Stock motors run one coil, as does almost every car that competes in NHRA Drag Racing, and they squeeze more ponies out of a given motor that most people can imagine. I'm pretty sure a single coil can supply spark to any motor anyone on this site can build.
 

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What the **** is THIS?

People ACTUALLY COMING TO A POINT OF AGREEMENT?!?!?!?!?!

This is UNBELIEVEABLE!

I change my stance. Let's argue!

LOL

;^)
 

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I always have odd hours. College in the mornings (getting a second degree), working on cars in my shop all afternoon and early evening, and then studying till 12am------MY point being I wish I could get to these posts sooner, rather than being the last one.....hmmm

Single coil or multiple?

It's a matter of physics. Electricity only flows so fast and is limited by the E=mc squared (THE SPEED OF LIGHT) factor and Faraday's Law. Hence as engine speed increases, a single coil has less and less time to fully recharge before firing (known as "dwell time") the next successive spark. On our 6 cylinder Z engines that equates to Each plug firing once per every 60 degrees of crankshaft rotation.

At 6000 rpm on our engines with a single coil, the coil has to fire each spark at 1/600 second or at .001667th of a second. Easily attainable by the speed and distance at which electrictiy must flow.

However, we must not forget the factor at which the ECU can calculate timing. This adds a time delay hit to the overall timing of the spark on an ECCS or similar total engine management system.

The 83 280zx turbo ecu had a 3mhz proccessor (yes-"3", modern desktops run at over 2ghz) running off of a small fuel and ignition map stored on three 2Kb eeproms.

Modern auto ECUs that run at 10mhz also read battery voltage levels to help calculate proper dwell times for the coil, have faster chips whose processing times are offset by far more detailed maps stored on eeproms with 1 or 5 mb capacities.

But regardless of ECU Speed, even the most basic ECU can still get out its ignition calculations and dwell time to the coil within milliseconds. In terms of math at least every .0001667th (note the extra zero) of a second--ten to a hundred times fast than the spark can fire.

What does this all lead to?
Not a whole lot. Any car can run on a single ingition coil and do fine.

The reason the use of multiple ignition coils were introduced were to improve combustion efficiency and greater power (maintain an escalating power curve) at higher speeds by producing multiple sparks at high engine speed ( 1 spark slightly before tdc of the cylinder, one at tdc and one slightly after or at whatever the ecu determines is best) to insure total fuel burn and greater engine power and long single hot sparks at low speeds. Also hotter sparks and multiple sparks are needed at higher pressures in the cumbustion chamber. (Note:diesel engines run at compression ratios higher than 20 to 1, because high pressure creates heat and it is the hi-temps induced by the high compression ratio that ignites fuel, this is also why we need intercoolers for our z turbos; to help eliminate the heat factor caused by the intense pressure the turbo creates and thus reduce the chance of pre-detonation).This is neccessary in turbo engine where the psi within the cumbustion chamber is imense. The theory is that knowing that gases can be compressed into liquids, at higher pressure the voltage in the spark plug can end up transversing the compressed gases (air and fuel) as if it were traveling through a copper wire and thus produce less of a spark than is needed to properly ignite the fuel. Note that pump gas also only burns at a certain rate, so that as engine speed increases, engine fuel has less time to burn. At high engine speed and full throttle (hence my name "Pedal2Metal" --:)) ) there is unburnt fuel and thus a diminishing horsepower curve. If you asked a single coil to do this, it would have to fire a spark every .0000925 seconds on a 6 cylinder engine. You would be getting close to surpassing electrical limits.

The verdict:
Mutliple coils are best if you have an engine managemnet system that can properly utilize it.

Ken Hawkins mentioned that NHRA drag cars use single coils. Well. this is partly because of regulation. Most importantly, this is because of the fuel that they use- various combinations of alcohol and nitrogen (the most combustive stuff in the universe). These fuel mixtures burn at 10 to 100 times the rate pump gas. The fuel mixture erupts more violently. This is why on an equally built engine on pump gas you may get 1000hp while a top fuel dragster gets upwards of 4000hp.

May I mention that multiple coil ignitions grew out of racing development on F1 and GTP and GTS cars that run at much less volatile fuel mixtures than NHRA.

My two cents......

Working on my 3rd 83 280zxt and a 03 BMW M3-in the middle of a build-up process to be the first flagship cars for my company, P2M Motorsports.
 

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Multiple coils share the heat load of a sinle coil across 4/6/8

They also have more time to build magnetic field (or charge if capacitive front end).

Seems like a very high performance need.

at 9000 rpm, the coil is firing 450 times a second on a 4cycle 6 or 0.0022 secs between sparks.

Share this amongst 6 coils and you get 75 times a second or 0.0133 secs between sparks. (same stress as car at 1500rpm)
 

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different part number...

in my book.
Aftermarket units may be universal, but the turbo Z31 had a different part number, and is specifically called out by NISMO in their competition prep discussions.
 
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