I have an 05 VIII I have installed o2 housing and TBE, AMS Lower Pipe, HKS Upper Pipe, HKS RS Intake, HKS 272 Cams, 255 Pump, stock turbo, stock ic, EBC set at 18psi. Now I have a set of injectors that I never installed for 2 reason. I ordered 680 cc injectors and I think I got 780cc. And the other reason is I spoke with Al briefly last night and he said that stock injectors make more power and are easier to control but I don't think I explained that I wanted to run 25psi on c16. Now I was planning on getting tuned for Dual Stage Flash 20 psi on pump and 25 on c16. Now my question is wouldn't I benefit from the larger injectors since I have more room to tune them vs. stock which I will run out of duty cycle by the time I hit 22psi. If I'm wrong someone please let me know. But I always thought a slightly higher injector when race gas on stock turbo is used would make more power than stock injectors.

I guess I will keep the 780cc for when I upgrade to the green turbo

 

You will get MORE fuel with those injectors, but NOT MORE AIR to mix with said fuel with a stock turbo and stock IC. The only time you need bigger injectors is with a larger turbo, or an upgrade to a stroker motor. I have a "Stock size" turbo, with hotside, and still have been using stock injectors. I went up to a stroker, Still same sized turbo, and then, and only then, did I get larger injectors. Anyway. keep the boost in the cars efficency range, 22-23psi. ANYTHING over that looks cool on the boost gauge, BUT, the compressor wheel is out of it's effective range/Sweet spot, so it won't benefit you. Stay stock injectors, and keep the boost in an effective range. My 2c.

 

The stock injectors atomize fuel more effectively and result in more power

We have tested stock vs 680 and 780 PT style injectors many times and the cars loose power (5 - 10 whp) as the fuel spray is not as fine

There is no reason to upgrade injectors on a stock turbo car

Stock injctors idle better, get better gas mileage and make slight more power

When you get a larger turbo then you need larger injectors based upon the amount of power you plan to make

Always use the smallest injector you can get away with then reflahsing the stock ecu - it works best with small injectoirs

Al

 

So what i'm going to do just put in some injector cleaner before i get flashed

 

Are they dirty? I NEVER used that before. 70K miles on the stockers, with 30K miles of LEADED fuel running thru them.

 

I would say they most likely are clean since I basically have been babying the car for about 35k but it doesn't hurt to throw some cleaner in the tank