Rob94hawk

iTrader: (1)

I have an old Crane PS91 coil from 1998 that I'm looking to replace. Looking at the specs of Crane and MSD. Can't find the specs of the stock coil at the moment. But what am I looking for in the coil? amps? voltage? turns? spark duration? Any electrical wizards want to step in on this one? Thanx

MSD:http://www.msdperformance.com/product.aspx?id=5063
Turns ratio: 100:1
Primary resistance: 0.68 OHMs
Secondary resistance: 4.8K OHMs
Inductance: 5.6 mH
Maximum voltage: 44,000 Volts
Peak current: 220 mA
Spark duration: 300 uS

Crane:http://www.summitracing.com/parts/CRN-730-0491/
Turns Ratio 54:1
Primary Resistance 0.430 ohms
Secondary Resistance 3.0K ohms
Maximum voltage: unknown
Inductance 5.5 mH
Peak Current 100 mA
Spark Duration 2,800 uS

GM 96 and up
unknown

Hypertech (Just for ***** and giggles)
Max voltage: 53,000 Volts

96capricemgr

iTrader: (1)

Just put a stock coil on it.

lt1slowz28

MIKE!!! get your electrical engineer butt in here and educate!

Rob94hawk

iTrader: (1)

Heard something about a 97 coil that was "supposedly" better. Searching ATM.

Search and ye shall find!:

tbag_skywalker

^This probably explains why there was no difference in how my car ran when I swapped my stocker for an MSD coil.

Catmaigne

iTrader: (6)

Or the fact that the stock ignition system is pretty damn good and there's no need to pay for a part you already have... Unless you really want some brand name eye candy for your engine bay. If it's red you gain 10 visual horsepower.

quik95lt1

iTrader: (7)

lol........ok quite simple.......first off ill say a stock single connector coil for the OP's application will be just fine..an MSD wont hurt though ......but down to the electrical part heres the deal......

P=IV (Power=Current * Voltage)

Voltage is the potential for transmission....current is the amount, current is what you are looking for...

reason why a 45000V stun gun will sting but not kill u but a 110VAC wall socket will put you in the ground......current.....

all performance coils will usually end up around the 45-55kV area its the current you need to look for......for example MSD HVC and HVCII Pro power coils....one is about half the price of the other but the voltage is higher on the cheaper one......why? the current output.....one has double the amperage....

for example.......

MSD Pro Power Coil
55000Volts @ .850 amps = 46.7KW

MSD PRO Power HVC II

only 45000 Volts but @ 2 Amps = 90KW

another words the acutal power output of the pro power II is double the other but has less voltage........

now if you want to take it a step fruther you can look at the max output spark time and convert into Joules (the measurement for work/energy)

A joule is defined as 1 joule = 1 watt/sec

so.....our first coil at 46.7kW with a spark duration of 180uS
46.7kw * .000180 = 8.406 Joules

our second coil at 90KW with a spark duration of 150uS

90kw * .000150 = 13.5 Joules


so as you can see all said and done the coil with the lower voltage and slightly lower spark duration still ouputs 60% more energy (Joules) per spark than the other coil does...............


again to get back to simple stuff........OP a stock coil is fine....if you want to upgrade there are plenty of options.....if you run into issues where you start blowing flames out that is where a strong system is needed however you shouldn't encounter that with your current setup........big coils such as the ones i referrd to above are needed in high cylinder pressure applications with fuel that is difficult to light off........i run an HVC Pro Power II on mine so i could open up my plug gap.......its a very very strong ignition with the MSD 7 Plus firing the coil.....then again im at 14:1 CR and lighting off exotic 114+octane race fuel and i can get away with running a plug gap over .030 with a very very cold plug and never have misfire issues......

Rob94hawk

iTrader: (1)

Thanx Mike.

Gonna call MSD this week and see what they recommend. Just having a minor issue of misfiring while driving after a cold startup. The opti is new. Plugs are gapped at .050". I'm sure the MSD HVC is overkill for an 11.6 CR and it doesn't look like a plug and play coil.

So it's either a weak spark or the fact that the 42# injectors are just too much for my setup during low rpm. Every time I'm done driving I smell like unburnt fuel.

Big Al

iTrader: (1)

And back in the 60's we ran 7200 RPM with one set of D112P's and a stock coil. The hot set up was a W&H DuCoil. Even Sox and Martin ran one.

Al 95 Z28

quik95lt1

iTrader: (7)

ill add some more to this lol...........

unless you are running the MSD 7 Box you cant run the two coils i compared there but you can run a smaller HVC.......you shouldn't need it though........42/s aren't too much to idle on, i've tuned stock ls1's with 60lb injectors to idle at 14.7 just fine........just as an experiment tighten up that plug gap to .030 and see what happens.....what are u running for plugs?

now from a tuning standpoint........with engines with large camshafts in cold air on cold start up they need to run a bit on the lean side......in theory you would want more fuel because of the density of the cold air and cold engine however if you cant completely burn this fuel all you are doing is creating an issue with the extra fuel..........for example.......my gto i run a smaller 224/236 112LSA cam.....that car needs extra fuel on the start up..........now take my camaro......26x duration ~106ishh lsa.....big cam lot of overlap.....that car i need to run at 14-15 AFR untill i get heat in it then its ok......ive tried it richer down in the 12's-13's but it WILL NOT idle, will misfire and will not burn the fuel completely.......you can only put in as much fuel as will combust properly any more is a waste and causes issues.......try leaning the car out on cold start i bet it will solve your issues........

Rob94hawk

iTrader: (1)

What plugs? NGK TR55-IX Iridium's. lol We had an argument about using them in another thread last year. You said you used them on a high CR forced induction engine cause it kept blowing the spark out.

As for leaning the fuel out, will look into this. I have no experience with tuning and don't have the software. What's worse is the local dyno shop who did my tune November closed down so at the moment I'm stuck.

quik95lt1

iTrader: (7)

Lmao oh Yeaaa I remember that now .........if u can find a way to download the tune just send me the file and ill modify it for u.....

pillarpod

okay i'll be the dumb one. You want the one with the best mA and OHMs

Rob94hawk

iTrader: (1)

Mike's saying go with the coil that has the higher current or mA.

You know I keep hearing how much better the stock coil is, whatever year, but I still can't find any info on it's stats. Trying to make an educated decision here, not just buy a new coil cause it's red and looks good with the rest of my red engine bay.

So I'm gonna go with the MSD. 1. Because it's put's out more current to the plug than my Crane Fireball coil and 2. Because I'm not swapping in my 20 year old coil, that I still have, for a setup like mine.

pillarpod

so did you get the one in your first post or did you get the street fire? Wouldn't the street fire be a better pick over the other? What i looked at was the mA is the same but the street fire has less primary resistance

http://www.summitracing.com/compare.aspx

Rob94hawk

iTrader: (1)

Didn't pick anything at the moment. Was looking at this but I don't know if the MSD 6 is needed to hook it up and when it comes to electronics/wiring I'm a total noob:

http://www.summitracing.com/parts/MSD-8253/

I was looking at this if I decide to go nitrous down the road and I would need the MSD box, I would already have the coil.

BTW, your link doesn't work and Mike would be the one to ask maybe he'll chime in.

96capricemgr

iTrader: (1)

If looking at ignition for spray the Mallory 685 at least deserves a look. Very complete package instead of having to add things on for every function.

Rob94hawk

iTrader: (1)

This one? http://www.summitracing.com/parts/MAA-685/

355z28

iTrader: (8)

Yeah that mallory box with the msd adapter harness is an awesome piece to work with. I ran it the last couple years and if I hadn't done 24x I wouldve kept it for sure!

96capricemgr

iTrader: (1)

I think that has the wrong adapters but is the right box. I don't spray so I haven't used it but I know a handful of guys who do use it with spray on LT1s.
Might PM bowtienut, pretty sure this is the one he uses when spraying.