Been talking to someone who was telling me that it is a popular mod in Japan to use 6 injectors with the PFC for SINGLE turbos by modding something inside the ECU.. anyone has more info on this?



Is putting on resistors on the injectors ..ie in the case of running 2x850, 2 x 1600's essentially the same as what this guy is saying ..or is this something else.. if it is in fact something else totally.. then watch out .



Here's a cut and paste from the email I got:-



"(snip) ...And if you modify the inside (ECU) of your Power FC, it can control six injectors. The modify is often called "Twin Drive." Notice that if you try to control the injectors by just modifying the wire, it would ruin the power transistor inside of the ECU. Thereby, the injectors will eject the gasoline at all times, and it might catch a fire. I will tell you that the situation is very dangerous and you don't want to barbecue your car, right? So just don't try to modify by wiring. If you cannot modify the ECU, then you have to use the other means of the injector control. This way you can use

2x850cc injectors for primary, and 2x850 + 2x1000 injectors for secondaries."



TIA,

3G7

i never heard of it. jspec or dragon ????

the way i was thinking about doing it (for 20b) is since the stock injectors are high impedance, you can run stock primaries (12-13ohms), and low impedance secondaries, and thirdinaries (850@2-3ohms and 1000@2-3ohms) thats say 2-3ohms times 4 = 8ohms so you only need restistors to make it like stock



mike

I think mike hit it on the head. I would go stock primary and 2 X low impedance secondary's. https://www.nopistons.com/forums/pub...IR#>/boink.gif

Ah Ha ... you might be on to something there...



btw ..the folks in Japan whom I was speaking to .. is SCOOT...they seemed to be firm believers that you have to open up the ECU to run 6 injectors...



Haven't received a reply message from them though.. maybe they are trying out your idea ..he he



3G7

they might do something like that on the inside? i dunno, thats how you could do it.

hmmmm, maybe that would work on a stock ecu with a super afc?!?



mike

Hmm still no replies on this.....I talked about this on the other forum and the PFC does not allow you to run more injectors than the car came with. The owner of Border told me to splice into the harness of the existing injectors. Maybe Scoot is wiring and additional injector controller or some kind of Modification to the ECU in order to run additional injectors Im not sure. It seems like a waste of time when you can just run the properly sized injectors right there and not have to mess with additional injecotrs.

i still wonder what you would do inside the ecu to add injectors? add another driver? have and exra output on a pin they dont use otherwise?



mike

The injector driver will handle 6 injectors stock.. there is a bunch of stuff on the datalogit e-mail list on it and the guys who made the datalogit are running 6 injectors now and have been doing it for a long time... I'll try to dig out those e-mails in the next few days and post them...

that would be cool :bigthumg:



mike

That would be neat to read. Please hurry up and post that stuff.

Ask and you shall recieve...



T-2 How to add a pair of additional 550 secondary injectors ^

o Plumb 2 extra series 5 (Gen2 T2 FC3S)-550 cc injectors into a

spacer between the inlet manifold and the plenum chamber,position

them to inject into the secondary runners.This Spacer /Auxiliary

injector holder will be available from FC-Datalogit soon.

o The series 5 (Gen2 T2 FC3S)550's are high impedance (15 ohm)so

they can be driven in parallel with the existing 850 secondaries.

o The injector drivers in the PFC are FETs.The IC contains 4

separate FETs,rated at 0.25ohm on

resistance and 3W max power dissipation for all 4.

o Driving 1 x 15 ohm injector at (say)15V BatV is 1A,so power per

FET is I ^2R =0.25W.Therefore the total power on the driver chip is

1W (at 100%injector duty)To drive the 2 secondaries together will

be 2A,and therefore power will be I ^2R =2 ^2*0.25 =1W.So the

total power for 2 primaries +4 secondaries will now be

0.25+0.25+1+1 =2.5W which is ok for the chip.

The result (FC-Datalogit team road test)was excellent.No

noticeable injector transition glitch's.Same smooth power at 1.0bar,

and injector went duty from 95%to 70%

o Note at 70%,the injector driver chip will only be dissipating

0.7*2.5W =1.75,which is fine.We plan to add a clip on heat-sink to

the chip though -all the same.You may wish to do that also.

o We also intend to scope the injector circuit -since you should really

modify the snubber circuit also.This consists of 33ohm in series with

0.47uF capacitor to ground.In theory we should halve the resistor

and double the capacitor to achieve the same.This could be modified

in the PFC,or added externally.We will explain more latter.

now sombody who understand electronics better than me tell me if it can handle 3 low impediance (4 to 5ohm) injectors in series = 14-15 ohms (same ohms as the stock secondary) on each of the secondary power wires + 2 stock high (15 ohm) primary injectors... for a total of 8 injectors...

thanks dragon. if i remember from skool right the formula works like this:

v

-------------- = watts

ohm * amp





mike

bump

I tried running two stock 850's in the primary and 4 low impedence 850's on the secondaries and it would not work. I just bought a haltech for this reason. I know from experience not just guessing. And I also tried several different resistors with no luck. The low impedence injectors draw too much current and will not open properly. I can only assume that when you are just running a pair of 1600's in the secondaries, the circuit can handel the current but when you have 4 low impedence injectors you have doubled the current again and therefore will fry the PFC or not open the injectors. Don't know if this helps much but I thought I would share my experience.

Nick

I am installing a set of 1600 secondaries as we speak but the only resistors I got locally were 10 ohm 2 watts ..not the 10 ohm 1 watt that most folks use.. I spoke to a friend who is a elector-geek and he told me that it shouldn't be a problem... the 2 watt just means that those resistors can handle more voltage.



any thoughts on this ??



TIA,

3G7

the way it sounds like it works is you are using 1 watt, and the resistor can handle 2 watts.



mike

Spoke to XS Eng and they said you can use the 10 ..heck even the 20 watt..just means that they will be able to handle more power.



Something interesting they said:



Even though most folks use 1 watt that is fine for most applications and driving around the street etc... but if you're running big boost and a drag launches.. you are better off going with something like a 20 watt ! ..it's an over kill but a safety margin you'd not have to worry about.



Just something to think about.



3G7

yeah they are right, its not like the 20 watt one is a lot more $$ and if the 1 watt one fails?



mike

sorry to bring this old post back from the dead.

but is there anymore info on running the 6 injectors on a 3rd gen.

i have 2 850s and 2 1300s and i don't want to buy a rebic with extra injectors when i go with a big single.

thats what this whole thread is about



mike

Dragon did a good job explaining it, but he said T2 at the bigening of his explanation post and that just threw me off.

so everything he said is supposed to work on an FD right?

theres no difference between the mods to do this to an fc or fd



mike

I use 10ohm, 20watt resistors per recommendations from others. They seem to work fine although I'm not sure what high boost has to do with the power running to your injectors?!?



I would just prefer those resistors be underworked than overworked and frying... https://www.nopistons.com/forums/pub...DIR#>/wink.png



K