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Old 04-01-2005, 03:36 PM   #5
Scooby Newbie
Member#: 42323
Join Date: Aug 2003
Location: VF35, Pinks
2004 WRX
Silver - UTEC, Tuna, TBE


Originally Posted by WRXout
so if i change this to like 18, will it effect fuel? retuneing needs to be done? is that what causes knock? and maybe hesitation i get every now and then, but it was tuned liek that wieerd
Lots of questions at once.

Heres the big picture. You have columns that tell the car how much fuel to put in. They are done by taking the fuel parameters and dividing. So if you have set 20 psi as your absolute max, at 16psi your car would use the 80% column. 16/20 = 80%.

Just remember that the higher the % column the more fuel is being put in.

Now if your car is constantly hitting 100% load because your max psi is set low -- you arent using the fuel map very well. You should only hit 100% when your psi is maxed. Then the fueling will be maxed (not maxed out meaning dumping stoich... meaning putting in fuel at the highest rate needed). If you are only hitting 80% of what you can in terms of boost, you should only use 80% of that fuel amount.

Get it?

Why could this be a problem? Because if your car is setup to put in the same amount of fuel when you hit 16lbs as when you hit 20lbs, you are obviously going to be much leaner at 20 lbs.

If the car is running alright, then I wouldnt worry about it too much. Its just not tuned well. Its confusing at first, but your boost/timing/fuel maps are all related. Whatever boost you are at is divided by the max boost you set it your params. That gives you a load %. Thats used by the fuel map to determine how much fuel to put in.

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