tuning beginner

[1992awdlaser]

Originally Posted by kenamond

If you're going with DSMlink, go with large injectors (around 1000cc/min would be nice). DSMlink can handle them and you'll have incredible growing room. If you don't plan on making a monster out of your car, something in the 800-900cc/min range would do, too.

You *cannot* upgrade your injectors without some sort of tuning tool like DSMlink, S-AFC, or AEM-EMS (there are others of course). The ECU expects stock injectors and will pulse them exactly the same in open loop mode as if they were stock (it'll look at the fuel map, determine how long to pulse the stock injectors to get the correct fuel, then pulse). If you increase injector size, the car will run rich at WOT and there's nothing you can do about it without a tuning tool. So you have to upgrade injectors and tuning tool at the same time.

Also, the stock fuel pump can't provide enough fuel flow to support more than around 15psi boost. At that point, the injectors are flowing so much fuel that the fuel pressure starts to drop which means less fuel goes through the injectors when they're pulsed open. So when the fuel pump can't keep up, you run lean at WOT and damage the motor.

And when you upgrade the fuel pump, you'll need to upgrade your fuel pressure regulator at the same time. The larger fuel pump will flow much more fuel than the stock FPR can regulate (the FPR lets fuel return from the fuel rail back to the fuel tank while keeping the pressure in the fuel rail at a certain pressure), so the fuel pressure in the fuel rail will go too high (the FPR gets "overrun" and can't return enough fuel to the tank) which will cause more fuel to flow through the injectors when they're pulsed open (higher fuel pressure forces more fuel through an open injector than lower fuel pressure).

I'd recommend reading through the stage 1 upgrade path. It explains a lot of this. There is an order to upgrading, and if you do it in the wrong order, your car will run poorly or not at all and you'll end up having to buy other parts (that should have already been installed) to get it to run correctly. But it's not really that complicated once you understand it

Just want to add to this. Some people say oh I don't need an upgraded fpr my car runs fine. Well the car will be running rich and sometimes it won't make the car run worse. But, when it is doing this all the extra fuel is washing down the cylinder walls which will contaminate the piston rings which will cause blow-by which will mean you need to rebuild.

[debbie]

this stuff i do understand so lets see if i get this, ill need the DSM link to up the fuel and so on, bigger injectors to deliver a bigger pulse of fuel, a bigger fuel pump to provide the fuel and a regulater to control the fuel flow. (and a nice bank manager)

[1992awdlaser]

Originally Posted by debbie

this stuff i do understand so lets see if i get this, ill need the DSM link to up the fuel and so on, bigger injectors to deliver a bigger pulse of fuel, a bigger fuel pump to provide the fuel and a regulater to control the excess fuel. (and nice bank manager)

Are you asking? Because if you read post number 30 that stuff was just explained.

[debbie]

Originally Posted by 1992awdlaser

Are you asking? Because if you read post number 30 that stuff was just explained.

no dude think i have it thank you