Crankfire vs. Distributor????, anyone have hard numbers???? Options

[Mueller]

Does anyone have dyno numbers or know where to point me to for a comparison between the two different types of ignition??

Knowing that I can turn my regular distributor into a fully electronic programmable electronic ignition (okay, it'll still have the rotor which must distribute the spark) I was wondering what the crankfire has over the distributor ignition besides 0 moving parts that can wear out.

for the distributor the path for the spark still needs to go from the coil>rotor>cap>sparkplug wire>sparkplug....

the crankfire is coil>sparkplug wire>sparkplug

what effect does the rotor and cap have on ignition if everything is the same (advance curve and coil rating)????

[fiid]

Here is some guy spouting "info".

http://www.rhinoracing.com/yaw/ignition.htm

[Brett W]

Mike

A crank trigger is the only way to go if you have the option. I doesn't have the problems that a dizzy has, worn out parts, limited accuracy, etc. A crank trigger can more accurately measure crankshaft position, will not wear out. I doubt you will see a measurable difference in a crank trigger and a good quality dizzy (Mallory, MSD, etc). What you will find though is the ability of the supporting systems to make more power. Typically crank triggered systems are some sort of computer controlled unit. This allows individual cylinder timing and fuel optimization, that is where you will find more HP and torque.

Crank triggered coil on plug ignition is about a close to optimal as us mere mortals can get. Be nice when Megasquirt figures out how to do timing without using the dizzy.

[SLITS]

Crank trigger is dead accurate due to the lack of torsional twist in the crank as opposed to a cam activating heavy valve spring pressure (amongst other things)

[rdracrdave]

The crankfire system is just more precise . The distributor shaft Rides in bushings and is driven by a gear thats driven by another gear . All of witch are prone to wear.
The proof is obvious when timing a crankfire engine, versus a std, distributor . The timing mark is rock steady with the CF system . The distrbutor fired system visably jumps around.

Dave

[lapuwali]

Speaking strictly theoretically, if you have the distributor provide both the timing signal and distribute the spark (the box figuring the advance), then you're still subject to spark scatter from slop in the distributor drive. Much less of a problem on a Type IV, since the dizzy is driven off the crank rather than the cam. I've seen some positive statements quoted for one of those multi-coil setups driven off the dizzy (which is only used for the timing signal, not even distributing the spark). Generally, they'll say things like "still runs smooth with a huge plug gap", or something like that. So far, I haven't seen any quantitative tests that show the advantages of running that huge plug gap. (NOTE: this was on other engines, not a Type IV, not even an aircooled engine).

Besides the obvious wear problem, I think the main advantage of a distributorless system is that, by reducing spark scatter, you can run the timing a lot closer to the detonation limit w/o going over it. Many distributors (esp. cam driven ones) can show 6-8 degrees of spark scatter even when new. It's even worse if you're running points. However, in practice, that spark scatter doesn't seem to prevent Jake, et al, from reliably getting 70-80hp/liter out of a Type IV. I suspect that if unless you're running right on the limit, you'll never see the difference between a fresh distributor and a distributorless system. Of course, you don't see much difference between a fresh set of points and a breakerless system, either, unless you're revving the piss out of the engine.

I like the idea on a theoretical level, but I strongly doubt there are any practical benefits other than eliminating wear as a factor. On a 120hp/liter S2000 or a 180hp/liter bike engine, maybe. On a 60hp/liter Type IV, no.

[Jake Raby]

I have used crankfire on the dyno against a 009 as well as a Mallory system...

setting the crankfire up advance wise was a challenge. Out of the box it did WORSE than the Mallory. After it was set up it made 11HP and 18 lb/ft of torque more. They both spanked the 009s ass so bad that it wasn't even funny...

I'm thinking about offering my system again, since I talked electromotive into making the coil packs for it again. The buggest trich was the trigger mount. I have plans for them and have made them work many times...

[DNHunt]

Megasquirt can already run a Distributorless ignition system.

It marries the Ford EDIS ignition with the Megasquirt ECU with only a couple of modifications. The EDIS system uses a 35 tooth wheel with 1 tooth missing and a variable reluctance sensor to track crank shaft position. The EDIS module controls dwell and provides the coil drivers. Timing is programable along with fueling. The coil provides spark to 2 cylinders at a time. On compression it provides spark for combustion and the opposite cylinder recieves a wasted spark.

Dave

[lapuwali]

There are a number of variations on the EDIS system, too. The trick on the T4 is making and mounting the trigger wheel. The best thing I've heard of so far is replacing the spacer between the cooling fan and the fan hub with the wheel, and mounting the trigger in there somewhere. If you did this, the EDIS setup is by far the cheapest and easiest way to go. Jake, if you sold the trigger wheels and pickup as a separate kit, you'd sell at least one of them (to me). The Electromotive stuff is expensive, but used coil packs, a used EDIS box, and one of the DIY controllers (MegaJolt Jr Lite, for example) could be put together for no more than an optical Mallory. And it would never wear out.

[airsix]

I was wondering what the crankfire has over the distributor ignition besides 0 moving parts that can wear out.

Hi Mike! Wow, what a coincidence. Guess what I just did? I just came in from driving my 914 for the first time with crank-fired ignition! I can see it in the papers now "Monkey sucessfully fabricates hall-effect crank possition sensor for 914" (IMG:style_emoticons/default/laugh.gif)

Seriously. Remember a few years ago when I was trying to fab a crank possition sensor with magnets mounted in the rim of the fan pulley? Well the failure of that project has been bugging me for years so tonight I went out to the garage and dug out all the pieces and tried again. It wasn't the physical design that was the problem it was the wiring. This time I shielded the signal leads all the way to the ECU and bridged them to +12v with 1k ohm resistors so that when pulled to ground they would make a nice crisp square wave. It worked! Engine fired right up, I set the timing baseline with the laptop and went for a drive. It was sweet.

If you recall I was previously running a Crane optical sensor in the dizzy. With the optical trigger there was much less spark scatter than with points, but there was still a noticeable amount. I think it's probably because even with a tight dizzy there is gear lash between the dizzy shaft and the crank, not to mention dizzy shaft wobble. I bet at idle speed that dizzy shaft is rattling back and forth across that gear lash. Running off the crank-trigger there is much less spark scatter as viewed with the timing light. The engine definitely idles more smoothly. I don't expect that there is really any more power - maybe a little, or like has been said - the potential now to extract a hair more, but nothing earth-shattering. It definitely seems smoother though, and I like that. It's still firing through the distributor for now (for spark distribution only - not timing or crank possition). I've got the coils for waste-spark but need another compatible ignition amplifier. As soon as I round one up I'll try to go distributorless and see what happens.

-Ben M. (now with new improved crank-fire action)

[tat2dphreak]

(IMG:style_emoticons/default/pray.gif) great job airsix!!!

how hard was this upgrade? tell me more!!

I'd never really thought about distributorless ignition on the 914, but I'm intrigued now... (IMG:style_emoticons/default/idea.gif)

[Mark Henry]

Ya'll like my dizzy???

SDS with crankfire....Yeah Baby!!! (IMG:style_emoticons/default/cool_shades.gif)

[airsix]

(IMG:style_emoticons/default/pray.gif) great job airsix!!!

how hard was this upgrade? tell me more!!

I'd never really thought about distributorless ignition on the 914, but I'm intrigued now... (IMG:style_emoticons/default/idea.gif)

I'm running an aftermarket digital ECU. That's what made the project doable. To use crank-triggering for your ignition you need a digital controller to control the advance curve. If you are not planning on replacing the stock injection it's really more trouble than it's worth. However, if you are converting to Megasquirt(+ignition) or other digital ECU that can control the ignition, I'd go for it.

-Ben M.

[airsix]

Ya'll like my dizzy???

SDS with crankfire....Yeah Baby!!! (IMG:style_emoticons/default/cool_shades.gif)

Cool. I sent a picture just like that to Jon Watts about 3 years ago. Right before my crank-fire project fell on it's face. That was right before I gave up and put the dizzy back in. Ever since then there's been an expanable freeze-plug in the top right-hand drawer of my tool chest just waiting to plug the hole currently occupied by my distributor. It's been waiting in that drawer since 2001 and I think I'm finally going to get to use it. (IMG:style_emoticons/default/smile.gif)

-Ben M.

ps - Drove the 914 to work. I always love driving it to work after a big modification like this. It's kind of ceremonial. Not the same as "test drives".

[tat2dphreak]

ahh... I wasn't planning on going back to FI anytime soon... I may do Megasquirt later and do this then...

[Mueller]

Ben,

How many sensors for the crank position?

For the above distributor setup I mentioned, 4 sensors are used for crankshaft position.

I guess I should just go with the EDIS crankfire I have, I know it's able to support over 700hp and 9,000rpm with stock components on the Ford Mustangs (I think they do normally swap out the coil for an aftermarket unit)

Anyone have pictures of the crankfire wheel and pickup mounted on a /4 ?

I've seen Dave Hunts wheel, not too sure how or where he mounted the sensor.

[Mark Henry]

My homemade wheel...it has two trigger magnets and one sync.

[Mark Henry]

Backside

[Mark Henry]

front mounted

[lapuwali]

So, something like that, but with a 36-1 toothed wheel would work well for EDIS. On the MS lists, they've mentioned that the trigger wheels on Fords are rings, and not hard to remove from junkyard pulleys. I vaguely remember they're 7" in diameter, but I could be off completely on that. If so, making a simple plate to mount that to the hub should be easy. Then it's just a case of making a mount for the VR sensor itself (also junkyard available cheap, along with the rest of the EDIS setup).

Hmm. The PO put an 009 on my car (carbs), and I've been considering an optical Mallory, but this could be a lot more fun.