There seems to be a lot more people running mac valves and gm solenoids without resistors these days has anyone ever damaged a stock ecu or is it even possible to damage the stock ecu by using a 3 port that isn't matched to the stock BCS in terms of current draw.

 

Not that I have ever heard of or seen. I have done lots with no issues.

Mitch

 

Your thread title is a bit misleading. Guess you're trying to attract attention?

I run my GM 3-port without a resistor. Been like that for a few years. razorlab has been doing it for many years (3+) on several race Evos that he tunes.

 

I totally agree, I edited it.

 

I know it's probably been covered a thousand times before but as Ive only got my iPhone at the minute with no laptop access searching is taking forever, just how far out are these type of 3 ports compared to the stock BCS in terms of resistance?

 

Sorry about the the thread it wasn't intentionally meant to be misleading!

 

I know you weren't, buddy! I just did it to help fellow 3 port owners sans resistors to not click this thread in panic (like I did).

 

heres a link to the evoecu wiki page. Some of the popular 3 port resistances are listed.

http://evoecu.logic.net/wiki/3_Port_Boost_Control

 

Cheers for the link it seems that the GM is quite close in terms of resistance has anyone tested a grimmspeed as this is meant to be designed to work with the stock ecu I'd be interested to see the resistance.

 

I tested that one as well. Can't remember the resistance, but if you search in the ECUFlash forum, you'll find my results.

 

You do not want to wire it without any resistor because you´ll take the risk to burnout the output transistor in our ECU.
For a GM, resistor has to be 5.8 ohms - 3Watts.
Cheers,
C>

 

No one has ever burned out the circuit in the ECU when running without a resistor. Its an early concern that has proved to be unwarranted.

 

Thanks for the replys puts my mind at ease about running a 3 port without a resistor as from what I've read using a resistor can reduce the speed of the solenoid.

 

Just out of curiosity if you could damage the ecu by using a 3 port without a resistor what exactly would happen to the ecu would you lose boost control altogether or would it still work but incorrectly.

 

The circuit would burn out, and there would be no boost solenoid control.