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View Full Version : Fuel Injection upgrade .


Ratchet
03-23-2008, 09:18 PM
im sure this topics been covered to death . and if that be the case, then ima noob out .

i want to stay N/A .
i was told by a guy that top feed injectors will make my car idle rough .
seems that i can only find top feed injectors...and i remember seeing somewhere that i can get sidefeed but i forgot where and i searched for like 2 hours and its buggin that CRAAAAP outta me .

lilredstiffy
03-23-2008, 09:24 PM
you can use sr injectors in your ka rail.

Ratchet
03-23-2008, 09:28 PM
aftermarket or OE ??

awesomenick
03-23-2008, 09:30 PM
Both. If the injectors work in an SR, they'll work in a KA24DE, but not in a KA24E.

Ratchet
03-23-2008, 09:35 PM
so about the top/side feed....
will it really make my car idle rough and rich ??

i didnt think it mattered THAT much....

louisdaboois
03-23-2008, 09:50 PM
no. theres no difference in the flow rate versus top and side feed. as you know, top feed are the "norm", everyone uses it and its VERY easy to get opposed to side feeds. thats the only difference. the guy that told you that is a moron.

only differences you should be worried about are injector impedences. HI or LOW. That'll cause the injectors to act retarded if the wrong ones are used via what your ecu is tuned for. SR's and KA's run high impedence injectors, if you wanted to get injectors from a different car, lets say a DSM, and convert to a top feed fuel rail, then you would have to get whats called an injector resistor box since the DSM injectors are low impedence. This box converts the high impedence signal to the injectors from the ecu to low impedence.

One other thing to keep in mind, are injector size which are measured in lbs/hr or cc/min. you want to use the correct ones because, again, the ecu is tuned for a specific size. Granted, you could use slightly bigger ones, but you'll just run rich constantly and your fuel consumption will be a course for concern with gas prices like they are today. If you plan to do motor work and feel as if you need bigger injectors to accomodate for the work the best bet is to ask a tuner, someone who actually knows what they are talking about/ actually dyno tunes vehicles and get their opinion as to what size you should run.

IMO, just stick with the 270cc's that are on the KA already, advance the timing 5º and that'll give you a little bit extra kick aside from building the motor, for the time being.

Ratchet
03-23-2008, 10:07 PM
haha so 550cc too much eh ?? LOL

so then if i took lilredstiffys advice, got some SR injectors and upgraded the rail thennnn will that work out well ??

louisdaboois
03-23-2008, 10:15 PM
yeah, 550's on a stock motor and tune will suck. you wouldnt even get a power increase. You have to understand, that just throwing in bigger injectors isnt going to give you horsepower. It's a combination of things, air, fuel and spark all work together. think about getting like a bigger intake manifold, larger cams, THEN bigger injectors. let in more air so the injectors actually have a purpose instead of washing your cylinder walls.

Ratchet
03-23-2008, 10:30 PM
no no i understand that . i just like looking around for so i can get a better deal .

im picking up my cat-back and headers within the next week and a half . i already have a power intake . and im working on Spark plugs and wires right now .

my car has 181,000 miles on it and i dont think the injectors have been changed so i wanted to upgrade them now instead of spending cash getting OE ones when ima just replace them in a month with bigger ones .

johngriff
03-23-2008, 11:02 PM
You still will not need larger injectors than stock. If the engine has 181k miles on it, I would be more worried about replacing the engine than the injectors for racing.

To make power from NA
Make it light
Make it free flowing
Pimp out the ignition timing map.

More fuel isn't going to do anything for you other than MAKE THE CAR SLOWER.

Ratchet
03-23-2008, 11:09 PM
nuff said . thanks for your help guyys .