accel DFI question

[Sparky]

perhaps i did not search the archives well enough...or even online articles....but i could for the life of me find the info i need,

when running an accel DFI. can i change the impedance of teh injectors in Calmap? let say i just bought some new merkur injectors for my turbo project (running semi stock l-jetronic) but now i have bought a used DFI unit...i really hate to throw away the cash i just spent on the new injectors...and would like to be able to use them with my DFI.

 

thanks in advance!

[clint78z]

Of course you can run any injectors you want even Peak hold ones. Simply take your base fuel map and multiply by old/new.

 

Ie going from 270cc to 370cc multiply entire grid by 270/370 there is a ultility in calmap that does this for you.

[JoshB 240Z]

Clint,

 

Does this mean that the DFI 6.0 unit does not mind running either high or low impedance injectors? Are there modifications required to run either type? I am currently building a harness for my DFI and this will help me to get the system on the car and on the road.

 

Thanks,

 

Josh

[clint78z]

I believe there is no needed modifications required for low impedence injectors.

 

Go to a parts store and order a 4pin igntion module for an 88 chev pickup, you need to lock out the distibutor and have an adjustment where the vacuum advance used to be to set timing. This even mounts on same holes for an Normally aspriated 280z distributor. Make sure that you cround the case properly. This will allow Accel full timing control. Another not power to injectors comes from main fused power wire on DFI then goes to 4 seperate switched grounds.

 

Go here for more info and read those manuals

http://www.mrgasket.com/dfimain.html

I have an EMIC manual if you need it sent to your email, it's pretty big PDF format if you want.

 

Good luck

[BLKMGK]

Talk to the DFI folks FIRST. I believe that mods to the injector drivers ARE needed. If this is the case and you don't do the mods you will burn out the injector drivers eventually. The older DFIs are pretty close to souped up old style GM units (IMO) and I KNOW those had to be modified. If you cannot get a clue from DFI post on a GN board - they will know I'm sure.

 

FWIW - you may be able to simply use a resistor to do this rather than modify the ECU. The Toyota Supra uses one of these and my AEM computer is able to run low impedance as a result. Hrm, and are you SURE those are low impedance injectors? I think so too but double check...

[z-ya]

What you need to find out is what is the minimum resistance (impedance) the DFI unit can drive on it's injector outputs. Most aftermarket EFI computers have built in protection if the impedance is too low. My Wolf 3D system can drive a minimum of 1.2 Ohms. Go below that, and the unit will go in and out of protection mode, causing an erratically running engine. You won't damage the computer, it will just run like sh*t. Find out from the DFI folks what the minimum impedance is, and then measure your injectors with a good quality ohm meter. If it is too low by a few tenths of an Ohm, a series resistor can be added.

The sum of the injector impedance plus the series resistance should be just over (by a few percent) the reccomended minimum impedance..

 

Hope this helps.

 

Pete

[Sparky]

thanks for the info fellas....

 

it will be a couple of weeks before i get the unit...and another couple before i can hook it up. i hope yall can deal with my mass amounts of questions that i will be asking.

 

thanks again!