Blue 1250cc needs resistor box?

[caliboy23]

My friend is taking his car to get dyno'd on friday but heard he needs a different resistor box. This doesn't sound right to me but the guy at Auto Wave says if he doesn't get a different resistor box he'll fry his AEM ECU.

Is there any truth to this that anyone is aware of?

 

[Rob10_99]

What injectors is he running exactly? The new bluemax ones?
From what I have read bluemax is the only injector that wasn't intended for natural gas, I forget where I read it but apparently its a well kept secret if it is true.
Bluemax claims their injectors as being made for liquid fuels(gas). I was just looking at injectors today and the website says an injector driver is needed on the bigger injectors, at least the 1850cc ones.
Yeah, I was doing a lil e85 planning, check out their site there's a few paragraphs on low/high impedence injectors on there,

 

[caliboy23]

What injectors is he running exactly? The new bluemax ones?
From what I have read bluemax is the only injector that wasn't intended for natural gas, I forget where I read it but apparently its a well kept secret if it is true.
Bluemax claims their injectors as being made for liquid fuels(gas). I was just looking at injectors today and the website says an injector driver is needed on the bigger injectors, at least the 1850cc ones.
Yeah, I was doing a lil e85 planning, check out their site there's a few paragraphs on low/high impedence injectors on there,

Yeah I'm looking around right now to nail down a solid concrete answer for his exact application. Last thing we wanna do is fry the computer and blow the motor while on the dyno. I'm at their website now actually.

 

[dsmmatt28]

Im running blue max 1250cc injectors. E85!! NO resistor box. I havent had any problems and have been running the for the past year. Hope that helps

 

[twdorris]

Im running blue max 1250cc injectors. E85!! NO resistor box. I havent had any problems and have been running the for the past year. Hope that helps

Very interesting. This is with a stock DSM ECU? Any chance you've measured the resistance across the injector?

I have a set of BlueMax 1450s here on the desk that measure 2.5 ohms. I guess I would have expected that to eventually overwork the injector driver inside the ECU.

Do you just daily drive the car or do you do any road course work? Just curious how often these injectors are driven with high duty cycles.

Any reason for not running the resistor box?

Thomas Dorris
ECMTuning, Inc.

I guess I would have expected that to eventually overwork the injector driver inside the ECU.

Let me clarify that. I would have expected the resistors inside the ECU to overheat. That's what we've seen come through here before and we just assumed the person was running low impedance injectors without a resistor box.

Any chance you could open your ECU and look around the 4 blue resistors near the connector block? I'm curious if they're getting hot on your ECU or not.

Thomas Dorris
ECMTuning, Inc.

 

[dsmmatt28]

I have the stock ecu and keydiver. Jeff set the global and deadtimes on the chip. Been running the chip for a while now. I daily the car as much as I can and haul ass were ever I can. I have put 250 miles one day on it. Took it to the track raced and the talon brought me home with nothing broke. However I just purchased ECM link. My buddie heath is running the 1650cc blue max with ecm link and no resistor box. The most IDC that I saw was 84% if I remember correctly. I have twin wallys in tank as well.

 

[twdorris]

My buddie heath is running the 1650cc blue max with ecm link and no resistor box. The most IDC that I saw was 84% if I remember correctly.

Any chance you or your buddy would mind opening up the ECU case and looking around this area? I'm curious if there's any discoloration on those resistors (blue) and/or caps (green). Those components form an RC network in parallel with the injector driver. As the injectors are switched on/off that network charges and discharges with current defined by the total resistance across the box (missing in your case) and the injector. Less resistance means more current and more power dissipation required through those resistors...

Thomas Dorris

 

[Steve93Talon]

Im running blue max 1250cc injectors. E85!! NO resistor box. I havent had any problems and have been running the for the past year. Hope that helps

To clarify, are you saying you literally have no resistor box - including the stock one on the firewall? Or do you just mean no aftermarket injector driver box?

 

[dsm-onster]

That's what I was wonder as I read this. The 2.5 ohms is about right for oem injectors. So you should be fine with the OEM resistor pack.

 

[dsmmatt28]

I have the stock one but no aftermarket. I will pop the ecu cover and check.[/B]

 

[Steve93Talon]

I have the stock one but no aftermarket. I will pop the ecu cover and check.[/B]

Your previous post stating that you have NO resistor box is VERY misleading, you may want to edit your post to say no "aftermarket" resistor box then. Tom's post about checking your ECU was with the assumption that you had removed your stock resistor box.

 

[twdorris]

Tom's post about checking your ECU was with the assumption that you had removed your stock resistor box.

Indeed it was. If you actually do have the resistor box installed, then ignore my previous posts.

Thomas Dorris