I've got a customer that wants to run 8 injectors for a 1/4 mile pass. 2 injectors per connector (in series) will lower the resistance to ~5-6 ohms right?. Can the injector drivers on an OBD1 ECU handle this for a 1/4 mile or should he run an OBD0 resister box to bump the resistance back to ~10-12?

The other question has to do with fueling and I'm think I'll have to increase the fuel map to compensate?

 

Running in series will double the resistance, parallel will halve the resistance. One connector operating two injectors will be parallel. If indeed you are wiring them in series(only one injector supplies power for both through the field wiring) then response time will be shall we say "interesting". If they are wired parallel( each injector has it's own power supply using a common driver) then the drivers will be subjected to twice the current draw they were designed for. I think it will survive for a drag race as I have seen many poorly thought out setups running DSM (Low impedence) injectors with no resistor box. Hondata has on their web site extensive testing of driver temps with low impedence vs high impedence injectors. If the injector driver should begin to overheat during a drag race then the engine will likely lean out. Tuning for all circumstances would require extensive R&D.

 

My mistake - I meant parallel like when you connect 2 4ohm audio speakers halving the resistance to 2ohms.

So if I run 2 injectors per connector in parallel it changes the resistance from 10-12 ohms down to 5-6 ohms and if I use a resister box, I can "restore" the resistance to 10-12 ohms and the injector drivers should run within their current range right?

If this is true then I only have to adjust the fuel cell values, possibly doubling them to get the same amount of fuel as only 1 injector correct?

 

Yes and yes, unfortunately we now have a voltage drop at the end of your resistor box and very sluggish behavior from your injectors. As for injector duration I have no idea or experience, all injector brands behave differently in their intended environment, your ideas will certainly compound these difficulties. I don't want to sound negative in this matter and in fact encourage you to think outside the box and experiment, just make sure the customer is on board concerning the possible negative re$ults.

 

Thanks for your help Turbokraft!

 

For tuning purposes & injector driver reliability it maybe easier to enable the 2nd set of four injectors in the high cam tables only via a relay system.

Obviously use a lean cut protection protocol to ensure the engine is not running too lean.

 

This is the only feasible solution in my opinion and something I've wanted to try for some time.