What Size Injectors?
 

I've been searching on an off all day for the answer to this question. So please don't ask me to search.
What is the biggest injectors i can fit in the stock fuel rail? I have a microtech lt-8 so i should be able to control them. I'm planning on making somewhere between 300-350 hp. Most likely i'll be upgrading to the BNR stage 4 upgrade. It claims to be good to somewhere between 350-370 rwhp. Any input on what kind of setup i'm looking at as far as fuel goes? I do have a walboro already so i think i have the pump covered. This is on a s5 but i have a set of s4 fuel rails sittin around if there is something i can do to them. I'm sorry if any of these questions are stupid i'm kinda new to the turbo area. Appreciate it.

unless you already have the turbo you should not go bigger that 720s becuase you will run pig rich.....even with the microtech you will have a hardtime tuning DOWN the injectors.........What are your mods so far?

Its a s5 turbo II motor, cone intake and 3" dp and exhaust, tb mod. I know they are nothing special but I took it to be tuned on a dyno professionally and i drove it too much before it got there and something inside is toast. The basemap was too lean with the simple mods i've already done. The tuner said it looked like i was going to be making close to 250 rwhp by the way my numbers looked. That was at 1/2 bar. The motor has a warranty so i'm not totally freaked out yet but I figure i'll make sure i have the fuel to be safe. I dont want to do anything crazy like 4x1600's but a friend made 290 rwhp on his s4 motor and upgraded turbo w/bad seals. He was running 2 550's and 2 1600's.

Bosch 1600's and your Microtech LT-8 cannot control them properly.


-Ted

What are my options with keeping the microtech?

720's to start is good, you don't need more with your current mods.....when you upgrade and you want to get rid of them then hit me up. right now 720 secondaries are sufficient.
1/2 a bar according to the stock gauge or aftermarket? You should be above 9psi with the intake and exhaust....invest in a BOV and either an FCD or AVC-R to get rid of the fuel cut. 250 sounds about right though, not to the wheels.........200 to the wheels.....keep us posted on that dyno.

Umm i have a STANDALONE. So i dont have boost cut. Its .5 bar on a greedy electric Gauge. And the Microtech says the same thing. I have a blitz bov. I know everyone says that boost creep is an issue but i do not have boost creep and the wastegate has not been ported.

that's strange, although, you do have an S5. my s4 crept to 20psi with intake and exhaust with a streetport and non ported wastegate. honestly tho, i tried 850's without any fuel management and they were too large. i think 720's will do you fine for now.

Do 850's fit in the stock fuel rail?

850's from what?
850's from an FD?  NO.


-Ted

So the biggest i can fit without modification to the fuel rail is 720's?

My bad, I had a brain fart.

i am also looking into upgrading my 2ndary injectors to 720xx or 850cc.
but need to know
1.which brand makes top feed high impedance for either that fit well into an S5 T2

I could have swore someone made drop in 850cc top feeds for an FC.

720 primaries with 850cc secondaries will have you covered for 350-360 rwhp.

There ya go.

Im still turning mine down, lol

So basically I should buy two 720 and throw them in my secondaries. And then when i get the bigger turbo i should buy some 850's(if there is some that fit), and put those in my secondaries, with the 720's as primaries? Sounds like a plan to me.

sounds about right. do it man. oh, and i got my stock 550's bored out to 850's by RC Engineering. Pricey, but they work

Sorry to bring this one back from the dead but exactly why won't my microtech control the 1600's? I refuse to buy a set of injectors and then buy another in 6 months. I know how to mod the 1600's to fit so thats the way i would really like to go.

Either ask the guys in the Microtech section or search in there for an answer.


-Ted

Try Marren fuel injection. They make 850cc injectors that fit the stock rail. I just bought 2 890cc injectors from them and put my 2 720s in the primaries location from the secondaries. The Marrens are $110 each.