ECU Comparison

[jimynick]

That's an old ECU. I find it amazing that stuff from the 70's still works and yet the new MP stuff lasts for days.

Mine's Mother Mopar's stock 1974 issue box and distributor and it works just fine. 

[blown motor]

Mine's Mother Mopar's stock 1974 issue box and distributor and it works just fine. 

Ya but yours didn't run for 35 years. Doesn't count. 

[rtgarage01]

6-12 V doesn't sound like much power going thru a ECU.

Voltage is only half of the equation.

Our design engineer was kind enough to put this together for us, he designs and builds gasoline and diesel engine control and dyno control systems for a living:

Good discussion, but the "amount of voltage" going to the Rev-N-Nator ignition ECU/ICU needs to be a minimum of 5 VDC to allow the board to function - that's it. All the ignition ECU/ICU (regardless of who made it) does is switch on and off the ignition coil ground (-) dependent upon the trigger from the distributor. The voltage of the power (+) going to the ignition coil is far more critical, which is fed from the battery through the ignition switch through the ballast resistor to the ignition coil (+).

And "power" a board can handle is a relative statement. Sure, large gauge wires handle lots of power, but so can PCBs in relative terms. The coil driver in the Rev-N-Nator is an IGBT which is rated at 51 Amps continuous. Some may think that's a lot, others may think that's not much - it's relative. Worth noting is that while signals on the Rev-N-Nator circuit board operate in the microamp to milliamp range, the IGBT coil driver is soldered directly to the PCB and carries the switched current of the coil (-). Even in very high performance applications the ignition coil draws about 8 to 10 amps maximum, and the heat generated from this operation is dissipated properly through the PCB. This design is common in every ECM, PCM and BCM used in cars and trucks today. There are just more IGBTs and MOSFETs carrying out the operations of switching the ignition coils and fuel injectors. Some may be surprised by this but the TO-3 transistor on the outside of the new Rev-N-Nator is for correct factory appearance, it actually is not soldered to the PCB and serves no electrical function. It is there only to provide the OEM appearance. All components responsible for dwell, switching, rev limiting and ignition coil control are insulated from the case and surface mounted on the internal PCB.

[dodj]

Thanks for posting that RT. I thought the external transistor was actually the IGBT and wired/soldered to the pcb.

Could the pcb actually handle that igbt at full capacity? Or was that size decided upon for dependability?

[rtgarage01]

Thanks for posting that RT. I thought the external transistor was actually the IGBT and wired/soldered to the pcb.

Could the pcb actually handle that igbt at full capacity? Or was that size decided upon for dependability?

You're very welcome! If you get a chance to look closely at the Rev-N-Nator, the TO-3 transistor is actually a run of the mill power transistor P/N 2N3055...keeps the decoration cost low.

Regarding the PCB IGBT throughput power handling, the PCB can handle a 0.6 Ohm ignition coil without a ballast resistor under continuous use, but the product is not warrantied for that. We require a minimum of 1.5 Ohms total primary resistance, ignition coil and ballast, with the Rev-N-Nator for street use. Without disclosing proprietary design details, there are other more important reasons and advantages for using this particular IGBT, the current handling headroom was insurance, a bonus. In the automotive ignition world, suffice it to say there are flyback voltages that need to be mitigated along with coil ring. If you are familiar with IGBTs, you will know they can clamp quite nicely.

One interesting nugget people may or may not know... A properly selected ballast resistor actually dampens the coil ring (resonance) permeating a car's electrical system. There are applications where using a ballast resistor actually helps versus running without. Probing around with an oscilloscope will reveal a great number of things, some help performance while others hurt it.

[71383bee]

UPDATE

After a lot of great discussion and consideration I decided to purchased the Rev-N-Ator system with the Firecore dizzy.  I finally got around to installing the box and coil 2 weekends ago.  Now with about 750 miles on it which includes a round trip drive to the Nationals from NW Chicago I can say that I am VERY impressed with the system. 

I thought I had the car pretty well tuned and running well before!  It was a very noticeable difference in idle quality and throttle response with just changing the box and no other adjustments.  The original setup was a 70/80's era stock mopar 4 pin ECU with a chrome coil (accell I believe).  From starting it up and taking it around the block for the first time I noticed it immediately.  Idle was way smoother and it was more snappy on the throttle.  Frankly it was pretty cool considering I did nothing else but change the coil and box.  I set the rev limiter to 6k which was super easy and it provides a slick light system which tells you the setting and acts as a tach when you're reving it.  I will re-tune the carb and likely get a little more out of it but so far I have nothing negative to say. 

Timing is 10 initial with total set at 34.  The stock distributor has a ton of mechanical in it and I'm sure I can get more initial which is why I opted to get the firecore.  But for now I wanted to just see if how the box and coil alone would do.  I want to use my current stock distributor to help me pinpoint optimum initial first and then I will tweak the firecore's mechanical advance and drop it in.  I expect that will also be a very noticeable improvement. 

I wanted to give props where it is deserved.  Its become a bit rare to get a high performance part to literally "drop in" and truly provide more performance but this is one of those cases where it absolutely delivers. 

Nice job R/T garage!   

[edison1970]

Where did you order the box from? Their website says it's on back order.

[Chryco Psycho]

Thanks for the review , the Rev-N-Ator is a good product for sure 

[tman]

UPDATE

After a lot of great discussion and consideration I decided to purchased the Rev-N-Ator system with the Firecore dizzy.  I finally got around to installing the box and coil 2 weekends ago.  Now with about 750 miles on it which includes a round trip drive to the Nationals from NW Chicago I can say that I am VERY impressed with the system. 

I thought I had the car pretty well tuned and running well before!  It was a very noticeable difference in idle quality and throttle response with just changing the box and no other adjustments.  The original setup was a 70/80's era stock mopar 4 pin ECU with a chrome coil (accell I believe).  From starting it up and taking it around the block for the first time I noticed it immediately.  Idle was way smoother and it was more snappy on the throttle.  Frankly it was pretty cool considering I did nothing else but change the coil and box.  I set the rev limiter to 6k which was super easy and it provides a slick light system which tells you the setting and acts as a tach when you're reving it.  I will re-tune the carb and likely get a little more out of it but so far I have nothing negative to say. 

Timing is 10 initial with total set at 34.  The stock distributor has a ton of mechanical in it and I'm sure I can get more initial which is why I opted to get the firecore.  But for now I wanted to just see if how the box and coil alone would do.  I want to use my current stock distributor to help me pinpoint optimum initial first and then I will tweak the firecore's mechanical advance and drop it in.  I expect that will also be a very noticeable improvement. 

I wanted to give props where it is deserved.  Its become a bit rare to get a high performance part to literally "drop in" and truly provide more performance but this is one of those cases where it absolutely delivers. 

Nice job R/T garage!   

I did the exact same by dropping in the new box, coil, with addition of the Firecore.  My results are exactly as you described. 

[RUNCHARGER]

Anyone have any experience in longevity with these boxes?

[71383bee]

Where did you order the box from? Their website says it's on back order.

I ordered through them.  Emailed and then followed up with a call.  They were super nice. but my setup was on backorder for about a month.  I was not in a super hurry so it was no big deal.  They offered to ship the dizzy out right away as they had it in stock but i opted for it all to come at once.  Id say the process between ordering and receiving was about 6 to 8 weeks.  I ordered it back in March. 

[71383bee]

Anyone have any experience in longevity with these boxes?

Good question.  That's why i brought the original coil and box with me on my trip to/from the nats.  No problems on that.  both trips were about 7-8 hours of constant driving each way and had no issues. 

Also worth noting that I am running stone stock 73 ignition wiring setup with the 4 prong ballast resistor and stock style plug wires.  I got their 2 prong ballast resistor just in case but so far it works fine on the stock style 4 prong. 

[dodj]

Nice!
I had the same experience when I changed from a chrome box to an msd 6a. Better idle and stronger 'off the line' grunt.
Ignition systems have come a long way since the early 70''s original mopar design.

[blown motor]

Anyone have any experience in longevity with these boxes?

I put a Rev-N-Nator box on with a Blaster II coil about 4 or 5 years ago on my 340. I put on 2-3000 miles a year. It's been flawless.

[gzig5]

Wow that doesn't make any sense at all.      

99% of everything being made now using any power is solid state PC board.

Are you still in the 70's?      

No, they are not. Pc boards are not capable of any significant power at all. They are good at signals, but not power.
For power, you need wires and good old crimp type connections.
I do it for living...pc boards do not handle power, they handle signals.. ...wires handle power. Regardless of the decade.....

I know this is a bit old but ........What do you consider "significant power"?  I have a product my company makes sitting on my desk that has an output of three phase 150 Amps continuous, 312 Amps peak at 480 Vrms all fed by a 680 VDC bus supply.  All that is going through a single multi-layer PCBA and this product is relatively small in comparison to some of the cabinet size stuff we make. Would you consider that significant?