Something I was email from Wolf AEM, thought it might be slightly relavent so chucking it up here. :cool:
Hi Guys,
We all know that increasing fuel pressure means you get more fuel per squirt right?
Well that is mostly true.
The first problem is, that as we increase the fuel pressure (using an adjustable fuel pressure regulator), the extra amount of fuel coming out of the injector does not necessarily increase proportionally. And this only gets worse as you keep increasing the pressure higher, and higher. The higher you go, the less of an increase in fuel flow you are achieving.
The second problem is that you can end up with the fuel pressure on the back of the injector making it harder for the injector to open. This can cause idle problems. This is especially true with high impedance injectors where there is not a lot of injector opening current to overcome the fuel pressure on the back of the injector.
Thirdly, you can have other problems such as less efficient injector spray, and injectors leaking when the engine is not running, but there is still fuel pressure in the rail.
Now, this all depends on the type of injectors you are using, but the general rules apply.
So, what is the answer?
Make sure you have the correctly sized injectors to cope with the amount of power you are trying to achieve. DON'T just screw the pressure up more and more. If you are getting fuel pressure up to numbers like 55-60 PSI at idle, that may end up being a lot more by the time you are at atmospheric pressure, or even more under high boost pressure levels.
Maybe take some advice from someone in the industry who has experience with a project like yours. It's far better to ask and get some solid advice, than it is to go the wrong way and end up with a substandard result.
OK, that's it for now.