Lorax

lets say you had the vitesse stage 2 kit kit or something like it, and you dont upgrade your injectors, the result wouldn't be catastrophic am I right? you would just flatten out your maximum power when the injectors reach the height of their duty cycle, or is there something I am missing.

azmi951

It will go lean, bad deal.

Lorax

So there is no way for the computer to know that an injector is reaching maximum and just back off altogether?

Lorax

I keep forgettiong im not talking about a stock cpu... got it now

Driftomagnifico

Some ECU's will cut ignition once the MAF hits a certain voltage. This is why HKS makes the fuel cut defenser (FCD) for some cars.

If you were to run too much boost on small injectors you'd get alot of detonation, in fact if you didn't let off it probably wouldn't take but a few runs like that to destroy a piston / headgasket / valve / etc.

Always try to have more injector than you have turbo. If the turbo pushes 400whp at peak output then opt for 72 lb. injectors. If it pushes 500whp then you can go with even larger. At the point you have 72 lb. injectors your partial throttle duty cycles are in the dumpster already, might as well just get something big enough to save the engine in case a wastegate line pops off.

Lorax

I was just wondering what would happen, but yeah that makes sense.

Porschefile

I say spend the extra amount and buy larger injectors. It's just not worth it considering how cheap injectors are and how much damage can be caused. The stock injectors are about maxed out at ~300rwhp. I have seen some pushing more hp with this on stock injectors by using higher fuel pressure, however that's not the best idea.

SD Porsche Fan

Bigger injectors increase your margin for safety. A MAF setup could easily out 'breath' a stock injector's capacity to supply fuel. It's even been suggested to me to go with bigger than stock injectors on a 26/8 with AFM and chips.

Lorax

My injectors seem fine on my k-26/8 with vitesse software, but yes if I were to make any real changes it would only make sense to upgrade my injectors, I was just wondering thats all...

Chris White

??? No problems with injectors up to 83lbs - then I usually go to full sequential to get a clean idle for 96lbs. I am not sure where you are coming up with 72lb injectors having a problem - hopefully you are doing something with the engine management to account for the injector change.

Tms951

injectors max out, turbo keeps going...and then.....Kaboom!

Why don't you buy a cheaper turbo like a lindsey unit and then you will have money left for bigger injectors.

Lorax

Im not actually buying anything right now, the question just crossed my mind.

Mike S

The other problem you'll run into is that the Vitesse software is written for a specific size injector. You run anything else and it won't work.

tconn

Mike S , not true.
Injectore size is selectable with the fuel quality switch.

fast951

Mike S & Tconn, you are both correct. The FQS settings differ between chips, each chip receives a document describing the FQS settings.

Ryan, the software must be matched to your injectors. The injectors must exceed the power capability of your turbo.