Been sent a few PM's reference this so I decided to put my standard answer in as a Technical Article. I did this back in '94 with the basics are as follows: - - de-pressurise the fuel system by running the car and removing efi relay, disconnect battery as injector feeds are live and fuel + sparks are only funny when it happens to somebody else - fit the extra injector / injectors into your plenum or preferably the crossover, preferably squirting with the airflow (I put my 2 in the crossover facing sideways but still works) Injectors Top.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17255&d=1176946378) - connect fuel line to the injector/s by placing a T piece in the fuel rail return line before the pressure regulator and if using 2 injectors a Y piece to split the line near the injectors. Fuel Tap In.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17256&d=1176946733) - locate an injector plug and tap into it to provide the pulse for each injector and (I used 1 & 6 as they were the easiest to get at) - splice 1 wire from the injector feed to the new injectors plug, the other wire you pass through your pressure switch so that it can control when it allows the injector to have a signal to fire - if desired you could parallel wire in a light to the switch to show when the injector it's controlling is firing. (I didn't bother) - Apply a vacuum / boost line to and adjust the pressure switch / switches to your desired activation point (easiest on a dyno using a multimeter and CO2 sensor to show when it comes in or you could cuff it with the lights) Tap In & Switch 1.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17257&d=1176946733) It is that simple, I didn't use a Hobbs switch but it was something very similar, off memory it was an adjustable oil pressure switch. I set mine to come on at 9 and 12 psi and haven't touched them again since fitting them as they still seem to be coming in OK. I used 2 standard VL injectors to enable me to stage the fuel rather than one large one just chucking a gut-full in. The type of injector doesn't really matter as long as it is low impedence and comes with mounting block and plug. Depending on what a pressure switch is worth these days (cost me around 40 each), the whole setup can be done for less than $200 including the 10 minutes minutes needed on the dyno. The hardest bit of the whole operation is the fitting of the injectors to the crossover, I took it to an engineering joint as I didn't have the tools to do it the rest of it only took me an hour or two. I'll answer any questions I can, but remember I set this up in 1994 and haven't touched it since. Pics to follow as I am going to be removing this setup because it won't be adequate for the next stage of development.

More images. Injectors Drivers.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17258&d=1176947225) Injectors Pax.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17259&d=1176947225) Injectors Top.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17260&d=1176947225)

More images again. Fuel Tap In 2.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17261&d=1176947363) Switch.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17262&d=1176947363) Tap In & Switch 2.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17263&d=1176947363)

And more. Overall.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17264&d=1176947440) Overall 2.JPG (http://www.calaisturbo.com.au/attachment.php?attachmentid=17265&d=1176947440)

good write up. top effort Some original photos have not been recovered yet.

good work buddy

good work champion.... i have my afm meter located right infront of my throttle body so i guess i cant run injectors /fuel running thru my afm

Probably not a good idea, BOV's aren't a good idea either as you will be venting fuel.

wouldnt it go threw turbo wen u let go of accelerator and it flutters

Extra injector setups are sweet when done properly for a little extra boost. Anyone interested should see if they can find an AVO microfueller setup. Or an old microtech fuel only computer, much the same as the microfueller. heaps of cars used these with good results. however in saying that. times have changed and technology has got better. ie better turbos, ecu's that can do everything.

im intrested in the answer too bouras comment

I just recently did an install similar to Alsynon, with some tips from him. the only difference in mine was i didnt pulse the injectors im simply holding them wide open. im using 2 set points the same as he describes with 2 seperate injectors. I drilled out 2 fittings and welded them into my cooler pipe right at the throttle body each with their own mounting point and also did as Alsynon suggested and put LED's showing when each injector activated. I have a N/A motor with simple boltons, turbo, throttle body, cooler, exhaust, and i made 220.5 RWKW on 14 PSI with this setup without pinging or leaning out. which i then ran at calder achieving a 13.3 at 103.29MPH with sheets to prove. Works very well and fairly easy to set up at a low cost. i will try to answer bouras question, if your injectors are close to your throttle body..and obviously have to be after your AFM you wont have any problems..fuel would never get the chance to go back to your turbo even without a cooler, the engine is still sucking some air even when the throttle plate is closed. Also the injectors will automatically shut off the moment the boost drops thanks to the pressure switches

Quote: Originally Posted by Bouras wouldnt it go threw turbo wen u let go of accelerator and it flutters It very well may, but I have never had an issue with that also it is quite normal for fuel to go through a turbo, case in point a carb draw through system. BOV to atmosphere would be an issue as it would definately release fuel vapour into the engine bay.

hmm well im going for it lets hope i get good power like doritoboy cheers ppl

It was a good idea 15 years ago. Now everyone just upgrades to aftermarket ecu and bigger injectors. Much better in the long run. I havent seen any quick VL packages running extra injectors.

well for a street car, standard management is more than adequate, what is a "Quick VL package" mid 12's is easily achievable..is that not quick? and for an outlay of 100 dollars..in the long run..i think its ok. my opinion

Quote: Originally Posted by redjetvlt It was a good idea 15 years ago. Now everyone just upgrades to aftermarket ecu and bigger injectors. Much better in the long run. I havent seen any quick VL packages running extra injectors. MRBTI ran a 10.2 off two extra injectors, and standard ECU, but its certainly the best method of geting into the tens :P

I'd be very concerned about using an existing injector to provide a signal to the extra injector/s. What you are doing is putting 2 injectors in parallel. 2injectors in parallel = double the current. Fair chance you could blow an injector driver circuit in the ECU.

Then perhaps the signal from the injector(s) could be used to trigger dome sort of transistorized driver? Would that work?

im heading for 2 extras? would running 2 na fuel pumps be enough to feed everything fine?