Aaron91RS
15+ Year Contributor
- 148
- 0
- Nov 10, 2003
-
St. Louis,
Missouri
Alright I'm upping the boost shortly on my 14b. Ok I should say upping it again. After the exhaust, with boost creep it hit 21psi before fuel cut. Fun times, fun times. 
Anyway I lowered it down to 10psi. Sometimes it creeps to 13psi. Now I have rewired the fuel pump, but the rest of the system is stock. So I was trying to figure out the weak links but need more proof then what people repeat over and over on message boards because they heard it themselves.
Starting with injectors at 450cc (42lbs/hr for us non-import people)
Running at 85% duty cycle mathmatically they support 292 HP.
With higher fuel pressure(ie stock AFPR) or higher duty cycle they flow more and should go over 300HP right????
So then I thought about the stock fuel pump. Supposedly at high load it flows it's worst down at 100lph (26g/h for us non-import people)
Thats roughly 180lbs/hr or more.(i live in america and am not converting anymore
)
Now the stock injectors at max duty cycle can only use a total of 168lbs/hr.
Thats all the math I did do for now, but if my numbers are anywhere close to right then I don't see the point of upgrading to a walbro 190 with stock injectors, or to 550cc injectors with a stock pump. The stock stuff seems very well matched together and yet when doing a search on this board many threads suggets upgrading to a walbro 190 when upping boost with stock injectors.
Other then the better safe then sorry argument can anyone show me the error of my thinking?
The stock stuff doesn't seem to be a problem till you hit 300HP???
*disclaimer*
I own a Camaro beside my 91tsi. I don't speak metric and I don't speak rice
*end disclaimer*
Anyway I lowered it down to 10psi. Sometimes it creeps to 13psi. Now I have rewired the fuel pump, but the rest of the system is stock. So I was trying to figure out the weak links but need more proof then what people repeat over and over on message boards because they heard it themselves.Starting with injectors at 450cc (42lbs/hr for us non-import people)
Running at 85% duty cycle mathmatically they support 292 HP.
With higher fuel pressure(ie stock AFPR) or higher duty cycle they flow more and should go over 300HP right????
So then I thought about the stock fuel pump. Supposedly at high load it flows it's worst down at 100lph (26g/h for us non-import people)
Thats roughly 180lbs/hr or more.(i live in america and am not converting anymore
)Now the stock injectors at max duty cycle can only use a total of 168lbs/hr.
Thats all the math I did do for now, but if my numbers are anywhere close to right then I don't see the point of upgrading to a walbro 190 with stock injectors, or to 550cc injectors with a stock pump. The stock stuff seems very well matched together and yet when doing a search on this board many threads suggets upgrading to a walbro 190 when upping boost with stock injectors.
Other then the better safe then sorry argument can anyone show me the error of my thinking?
The stock stuff doesn't seem to be a problem till you hit 300HP???
*disclaimer*
I own a Camaro beside my 91tsi. I don't speak metric and I don't speak rice
*end disclaimer*
