oldmansan

iTrader: (4)

According to Kingpin Performance, we don't need STI injectors. You can modify your stock injectors to flow 740-750. Taken from www.kingpinperformance.com

Its a tough choice on which injector to buy for your WRX. Buy STI Pink injectors? $300-$550 and you get an extra 100cc worth of fuel. PE 650 or 850's? $600-$800 a set and because these are mechanically slow you need tuning or a flash to make them work correctly. Other companies sell an option for $450 and another that requires you to solder in a resistor pack. You can skip all of this and make your own 740CC injectors for free.
The Stock Blue 440CC injectors and the STI pink 540s are identical other then the end cap and the color so either injector will work for this mod. There is no advantage to having the Pink STIs once modded so sell them, Make some cash and mod your stock injectors. There are a few ways to accomplish the mod but what needs to happen is the end cap of the injector needs to be removed. You can grind it off or cut it off. Does not matter really. You can use a band saw or a dremel tool and a vice. Take your time and cut the silver end cap off where the nozzles (holes) are.
Since you are removing the end cap you dont need to send these off to have them matched. There will be no adjustment a injector shop can do anyways since they are sealed units. What you are doing is removing the flow restrictor (end cap). The biggest advantage is that the stock ECU is calibrated for the correct opening time compensation for these injectors (dead time). PE's are twice as slow and need more dead time. All of the issues that the PE's bring to the table are absent with these injectors.

Questions:

How much will the injectors flow once modified?
740-750CC

What about the spray pattern?
You end up with a find disk pattern

What about the idle?
Rock solid idle as stock once AFR's are tuned.

What about reliability?
They are stock Denso injectors and you are just removing the end cap containing the sized holes.

Do I need a fuel pump?
Yes, Pressure at the injector is reduces since the injector body can now flow more fuel. You need a fuel pump capable of handing 740CC injectors. Walbro is fine.

What if I dont have engine management will these work on a stock ECU?
NO, You will nearly double the fuel flow so you will need a Utec, SAFC, Link, Gems, Flashed ECU or other EM to calibrate these injectors.

I am still worried about equal flow. How Can I be sure this works?
You can send the injectors To Venom performance in California or RC engineering for testing once the mod is complete. Venom will even do the mod for you and test each one but the cost is nearly $300.

Why are you posting this information and not selling modified injectors?
Because it costs nothing to do this mod and its better to give back to the community. If you do not want to perform this simple mod yourself there are companies out there that will take your $200-$300. Maybe one of the members will try this, report back and offer to mod your injectors for a reasonable price? $50? This way its worth his time to do it and you save a ton of cash in the process by not having to spend $450+ on injectors. Work as a community guys

How many cars have you tuned with these injectors and how long have people been running them?
Kingpin has tuned 7 cars with these modified injectors. All idle smooth, All run fantastic and all have low IDC's One customer has 5000 miles on his set now with out issue.

Hope you guys try this and report back. I would not suggest something that I do not believe it. Some of you can flow test them if you wish and let us know the results. Let the flood gates open!


Thanks

San (I read a lot)

iNfEk

iTrader: (33)

so you're just taking off the end cap? that's it?

Jon

mario

iTrader: (7)

San i'm worried about this mod If they flow at 740cc's, that may be too much for a VF turbo. This guy last time i read his post was having problems w/ his tune w/ 740cc injectors. This sounds like a great idea but not w/ a VF turbo like you and others have. here is ther thread on Nabisco.-->http://forums.nasioc.com/forums/show...hreadid=482937

oldmansan

iTrader: (4)

I'm not even thinking about this mod for my 34, but if I had more displacement and a huge turbo, this might work.

San

mario

iTrader: (7)

Do you need more fuel when you have more displacment??

oldmansan

iTrader: (4)

reread what I posted. If you have EM this mod should work fine. The thread you are looking at is a 740 injector, not the stock injector modified. I'll talk to KingPin and clear this up.

San

mario

iTrader: (7)

So if i wanted to run my Unichip maped for STi Pinks do you think these injectors would be to much??

So PE740 injectors are totally different from modified WRX injectors but flow about the same? San whenever you decide to do this you gotta LMK man i wanna check this out

mario

iTrader: (7)

Aww man i just reread some of your post it won't work unless calibrated w/ something unless its tunable

Nolimit

iTrader: (1)

you could use a SAFC to tune these injectors. And I think you already answered your other question (which was problems only applicable to the PE's).


Good info San!!!!! who wants to do this mod?? who has extra injectors lying around?? I will gladly perform the mod for you if you're not comfortable with it!

oldmansan

iTrader: (4)

as I have the STIs already, and will probably use those for the VF34. Depends on which engine management I go with. I'm liking what I see from Kingpin, but have waited forever for Cobb.

San

gpatmac

iTrader: (3)

This is what I was planning on doing once I'm able to go large.

oldmansan

iTrader: (4)

readingba myba mindba (Fat Albert).

San

gpatmac

iTrader: (3)

To add to this, for whatever reason I've been able to pretty significantly lean my mixture out but because of some recent changes in my tune, I'm over-maxxing my 565's (pinks). How much do you think 740 would lower my IDCs?

oldmansan

iTrader: (4)

but 10 divided by 100 equals .10 (10%), and 565 divided by 740 equals .76351351351351 (76%). If you're maxing out your pinks, I'm going to ask Kingpin about doing the 740s with a reflash. I'll just sell the pinks for a loss.

San

gpatmac

iTrader: (3)

Nah, I was thinking of cutting on mine own. This is just the initial spark of an idea which needs some fueling provided by research.

Wouldn't hurt if you were to ask them for me, though.