distributor or no distributor?

[MatBirch]

I've been struggling with my motor swap into my montero now for way too long.  I've come this far already, so I've commited myself to mpi.  I've decided to go with SDS for the system.  I'm definitely not looking for the super HP that alot of you are, I'm looking to improve reliability, parts avail. etc.  Anyway one of the options is to keep or ditch my distributor.  Any thoughts?  I have no history on the distributor I have so, I'm thinking maybe this is a good time to ditch it and go direct fire.  

 

Thanks-

--MatB

[ZeroKewl9]

I'm pretty sure that a distributor would be a cheaper route not to mention a lot easier to get working.  I've thought about both ways myself and have come to the conclusion...  What does the 7sec 2.6 run?? a Distributor unless my eyes are mistaken.  I feel that the most gain from a DIS would be SFI  like a GN  or coil per cyl like a LS1

 

Zero

[j5]

Get rid of the dizzy.

Better retard control.

Less drag.

I was gonna keep my dizzy but I'm glad i got rid of it.

The hardest part is making the bracket  and mounting the trigger.

The rest is easy.

[Boosted_One]

My SDS 4E controls timing electronically with the distributor. The actual igntion system is an MDS6A but the SDS controls the program end.

 

No advance weights, no vacuum advance. All the distributor functions as is a spark distributor.

 

I feel no more at a disavantage having the distributor at this point than not.

 

So it all depends what system you run.

[chiplee]

Yeah Mike I would be willing to bet that a good many people don't have the foggiest idea what you mean.  I wouldn't have if I hadn't installed a similar system myself.  Not that I was ever all that knowledgable before that, or after really.  But the point is that these DIS or coil pack systems are for one of two things.  Efficiency on the street, or all out performance in a race application.  If you're the average shade tree mech you don't need it.  And if you've felt how fast the Hawk retards timing for rev limiting you know what I mean when i say, it's fast enough.  If you understand how it works ignore the following but basically, the distributor on the Hawk is a simple Hall effect sensor like the one you would bolt on if you did a DIS system.  The distributor gives the ECU a crank position indication at 60 degrees before top dead center.  Upon receiving said indication, the hawk references the matrix that tells it how much timing the current ignition map dictates.  It happens extremely fast.  If the hawk finds programed timing to be 20btdc, then it waits 40 degrees after the trigger and fires the ignitor.  Thusly you get full electronic control of timing that is very fast and very reliable.  It works because the rotor button on the magna distributor covers a good 60* of travel inside the distributor.  Meaning that the spark from the coil can make it to the contact point because of the width of the rotor.  My understanding of a stock set-up is that the spark is going to happen when a mechanical trigger occurs, which is why moving the distributor changes base timing.  With the hawk, you set and forget the actual distributor.  Once you have it set all adjustments to timing are accomplished via laptop interface.  This was installed and running before I ever really got my brain around it, and I'm not 100% sure I fully understand how it works even still, but if anyone wants more clarification let me know

[MatBirch]

Thanks Guys-

Ya, Chip- I didn't have the foggiest-  Thanks, and even a little more clarification would be nice.  

My setup is now currently stock, coil, everything.  The car had 105k on it and I have no history.  I may soon be in need of things like coil, distributor anyway.  I think I'm reading that the management systems that retain the dist. require an MSD type ignition/coil?

Anyway, I'm starting from scratch, so I can go either way.  I want the easiest, most reliable system.  Not to say that money is no object, cause it IS, but with SDS, it's only a little more to get rid of the dist. and truly have the system "stand alone".

This truck will NOT be for racing or getting crazy, but it wont be a daily driver either.  I'm building this thing to be reliable, and strong, and to get away from things like 350 dollar injectors and TPS's mated to twenty year old wiring.

Am I making any sense ???

 

Thanks again

--MatB

[Boosted_One]

It's like this.

 

Coil packs, or distribtorless ignitions fire a coil for each cylinder and controls advance and retard via the ECU program. So in this case what is distributing spark is the ECU firing each cylinder coil pack. So there is no rotating mechanical parts, no advance weights and no vacuum advance to deal with.

 

Our distributors are different but perform the same function. Spark is triggered and sent thru the coil wire. The rotor spins and the spark is jumped to the cylinders via the metal terminals. The timing advance is controlled with mechanical weights in the distributor. The vacuum advance is also used to control slight advance and retard.

 

On my SDS system, which is similar to how the Hawk system works, is similar to the distributorless ignition. The timing advance and retard are fully programmable into the fuel ECU. So there are no timing weights in the distributor. The vacuum advance is not used either. So what you are getting is fully programmable ignition timing (just like the distributorless ignitions) with many of the mechanicals eliminated that can cause problems.

[Joel]

It's like this.

 

Coil packs, or distribtorless ignitions fire a coil for each cylinder and controls advance and retard via the ECU program. So in this case what is distributing spark is the ECU firing each cylinder coil pack. So there is no rotating mechanical parts, no advance weights and no vacuum advance to deal with.

 

You just descriped COP (Coil over plug), and until recently (last 5 years) you would hardly ever see that on any car at all, unless it was worth six figures. Generally this type of ignition wouldn't be needed unless you require 13k rpms or so (due to lack of time availible to charge a larger coil pack assembly). The only other reason is if you had the ability to run fully sequential ignition and could actually phase the ignition per cylinder, retard the timing on a single cylinder, etc. Quiet an expensive deal to take advantage of such a thing. You will now see more and more COP designs (s2000, WRX etc) because they can actually use sensor data and known variables from testing to setup individual cylinder trims for the ignition (as well as the fully sequential injection).

 

 

The term DIS/Coil Pack usually describes wasted spark. You have 2 "coil packs" which fire 2 plugs at a time (and since half the time the spark did nothing as that cylinder is not on the power stroke, hense the term wasted-spark). Generally a setup on DIS is good up to about 11-12k RPM using CDI (like an MSD box). Using the standard inductive type ignition, 600hp isn't unheard of, and 9000RPM to 10,000RPM is not uncommon.

 

On a distributed ignition system, 7000RPM is topping it out. It only has one coil, and the charge times only get lower and lower as RPM increases. I would say to get max power out of a distributed ignition, you would likely need CDI (Capacitive discharge ignition, like an MSD box).

 

Our distributors are different but perform the same function. Spark is triggered and sent thru the coil wire. The rotor spins and the spark is jumped to the cylinders via the metal terminals. The timing advance is controlled with mechanical weights in the distributor. The vacuum advance is also used to control slight advance and retard.

 

On my SDS system, which is similar to how the Hawk system works, is similar to the distributorless ignition. The timing advance and retard are fully programmable into the fuel ECU. So there are no timing weights in the distributor. The vacuum advance is not used either. So what you are getting is fully programmable ignition timing (just like the distributorless ignitions) with many of the mechanicals eliminated that can cause problems.

 

Pretty good explanation. However, Distibuted ignition is a little less powerful than a COP or DIS design. You can't build up the charge in the single coil fast enough that a deisng like this permits. If you go to compare other vehicles (like 8 cylinders) pumping out high HP from a distributed engine, You'll see far less HP numbers on a high output 4cylinder than you can with an 8 cylinder with simialr HP. This is due to peak cylinder pressures being higher on a 4cylinder to meet the same power requirements as the 8 cylinder. Don't get me wrong, the V8's did fine on Distributed ignition, but on a 4 cylinder that same power can't be had. As cylinder pressure increases, the likelyhood of a spark misfire (since air makes a nice insolulator) goes up. The DSMs have no issues with their stock setup up to 500-600hp when the car is placed in the right hands.

 

I went with DIS for a few reasons. First, I didn't have to tear up a stock distributor (and I could likely donate it to an unfortunate party later). The second, I had cheap access to RX7 TII coils (I'm sure anyone can find similar coils on ebay), which are known to allow for higher output then even a stock DSM coil/ignitor. That sets me way beyond needing to spend any money on an MSD. I saved money. The third reason was the output that could be had. I use 2 coil packs (twin tower) and two seperate ignitors which toggle back and forth. This helps distribute the charging duties between 2 seperate ignitors and coil packs, instead of having 2 coil packs and 1 ignitor. Charge times are generally int he 5ms ballpark up to 8000RPM, although some have had success with as high as 6.5ms.

 

Another thing to keep in mind, CDI is short duration. Mulitple spark technology that all the big ignition systems claim... it goes away after 4kRPM or so, as there isn't enough time to spark more than once. So peak power claims can't come from there. Inductive is high voltage long duration. The spark is there much longer than on CDI. There are pro's and cons to both, but theres nothing that'll work as cheap and effective as an inductive DIS setup, especially if your not revving to 10k+.

 

Joel

[MatBirch]

OK- Thanks guys-

All this has me learning a ton......... but also getting more confused ???

For MY application- Low RPM torque, probly never see 6k let alone 10, What should a guy go with?  I know it's a little vague, but the guys selling these management systems don't specialize in these cars- you guys do!  Let's just assume that I wanted NO MORE POWER THAN STOCK.  I know that's a stretch for you guys ;D but I just want this thing driveable.  RELIABLE!  My current setup is way screwy, and even with Shelby's undevided attn., we can't get it working properly.  Doesn't it seem wise to go with a system which eliminates as much of the old stock electrical, and electronic, as possible?  Am I just asking for more trouble?  

Someone I respect greatly suggested SDS.  What about the others?  Even Mega squirt.  MS does not seem to get rid of as much as the others, or am I wrong?

 

Thanks for putting up with me

--MatB

[Joel]

You have to make sure with whatever system you go with, it'll support your choice in ignition system.

 

If you want stock power, the stock dist will work fine.

 

If you want a ton more, you will likely buy an MSD box later if you stay with the dist. DIS, if the management you chose supports it, would not require a CDI ignition upgrade until much later (and possibly never if your goals aren't set higher than the sky).

 

It's still a choice thats up to you, more or less personal preference. You can certainly make more than 300hp on a stock dist.

 

Joel

[Boosted_One]

I run the SDS EM4E with a distributor and an MSD6 box.

 

The SDS fires the MSD6 so actually my igntion is an MSD6 CDI.

 

---------------------------

 

Joel... good post there... I was trying to keep it as basic as possible.

 

I've been working on my buddy's 2002 GT-S Celica and he's got a coil per cylinder mounted to the plug wire. SLICK set up stock!!

 

It's mandatory IMHO that you use a CDI. Even a top notch coil does not have enough on the upper RPM area.

[Joel]

CDI is not required on DIS for quiet a while. Plug gaps will be small, but all those 600hp stock coil DSM owners don't complain about what size their plug gaps are.

 

I stand by that opinion.

 

For dist. ignitions, CDI will be required eventually, I'm sure.

 

Joel

[jr_ss]

Joel, so what you are saying is that a stock distributor can be used with say an msd box for up to and above 300 hp. Like chip was saying, don't you just set the distributor and forget it, because the hawk allows calibration it on the laptop. I'm still alittle confused about this, I was just going to run my stock distributor with my jacobs electronic ignition if the hawk allows it to run with it. Would that be a good choice or would I have to swap my system completely....

[Boosted_One]

You'll be fine with a coil distributor and CDI ignition.

 

There's tons of cars making well over 300+ HP using coil/distributor/CDI.

[Joel]

Charge times on CDI are extremely low, sometimes as low as 0.2ms to fully charge a coil. CDI would definately keep a distributed ignition running top notch.

 

Joel