stock or aftermarket injectors

[-dsm4life-]

i am goin to rebuild my 420a and im not sure if i should keep then stock injectors or get bigger ones. these are the mods im goin to do i hope this helps and keep in mind im stayin n/a

crower stage 2 cams, crower valve springs and titanium retainers, wiseco 10.5 pistons, eagle rods, sbi lifters, sbi rocker arms, sbi valve guides, sbi valve locks, pep stainless steel valves 1 mm over sized, obx header, obx high flow cat, injen muffler, 55 mm throttle body, obx intake, cold air intake,msd coil pack.

so can i use the stock injectors and fuel pump or do i need to get better i looked and if i have to get better im goin to get the obx fuel rail and the walbro 255 fuel pump i just dont know about the injectors and what about a throttle body spacer is there any gain from it honestly i have heard people say yes and no i had a friend put one on his 99 rs and he said he noticed it but he isnt very car smart so he may think he noticed because it said he would Thanks

 

[NeMiZiS]

I would say yes, you'll need bigger injectors.
Just remember you will also need a way to control them.

 

[VelocitàPaola]

Remember that internal combustion engines work on the premise of an air/fuel ratio. If one is increased, the other should be increased too.

So here's a simple question to ask yourself when considering new injectors: am I adding any more air? More "air" comes in the form of a turbocharger, supercharger or nitrous oxide. If not, there's no reason to upgrade your injectors.

 

[NeMiZiS]

I'm saying yes, because Bullettdsm has bigger injectors on his car and he is the fastest N/A.

 

[VelocitàPaola]

I'm saying yes, because Bullettdsm has bigger injectors on his car and he is the fastest N/A.

That statement by itself makes a poor argument. You have to remember that Mark stuck with a mostly stock fuel system (including injectors, but a Walbro 190lph pump) for a long time.

 

[-dsm4life-]

so what size injectors would work with the setup im wanting to do and what would yall recomend to control the injectors and i dont plan on adding a turbo or anything like that i am goin to stay n/a for this carand down the road i may get a tsi or a gst but that will be years away. i just want to build a strong reliable n/a and still have some gas mileage

 

[VelocitàPaola]

I would stick with the stock fuel system (including injectors). Mark successfully used an S-AFC II for a while. If you're after maximum power, you'll want Megasquirt eventually.

 

[-dsm4life-]

so stock injectors and fuel pump will be sufficient enough for mods im doin? and no im not worried about max power i think ill make enough with that setup to keep up or smoke anything around here and to get me into more trouble than needed

 

[NeMiZiS]

So no matter you do to a 420A as long as your not adding a turbo, or nitrous etc.
There will never be a need to install larger injectors?.
I'm really not trying to argue, it just seems like at some point you would want bigger injectors.

 

[-dsm4life-]

if i puta bigger fuel pump like the walbro 255 would that help or would that be to much?

 

[VelocitàPaola]

if i puta bigger fuel pump like the walbro 255 would that help or would that be to much?

I don't know that the 255 would help, but it wouldn't hurt. For what it's worth, Mark has a 190.

 

[VelocitàPaola]

So no matter you do to a 420A as long as your not adding a turbo, or nitrous etc.
There will never be a need to install larger injectors?.
I'm really not trying to argue, it just seems like at some point you would want bigger injectors.

Remember the air/fuel ratio. If you're not introducing more air, then there's no need for more fuel.

 

[-dsm4life-]

k il get one of them and keep stock injectors how big are the stock ones anyways and whats you opinion on a tb spacer

 

[VelocitàPaola]

k il get one of them and keep stock injectors how big are the stock ones anyways and whats you opinion on a tb spacer

I believe the stock injectors are 190cc/min. The TB space is useless.

 

[-dsm4life-]

o ok would a 55mm tb have any benefits

 

[VelocitàPaola]

o ok would a 55mm tb have any benefits

Yes, it would.

 

[-dsm4life-]

how much power gain over a stock tb.

 

[VelocitàPaola]

how much power gain over a stock tb.

It depends on too many variables. Also, we discourage bench racing here.

 

[-dsm4life-]

what do you mean by bench racing?

 

[-dsm4life-]

velocita you said that if you dont add more air( turbo suprecharger or nitrous) there is no need to update injectors. wouldnt a cold air intake and a bigger throttle body and inake add more air? or does it add more air but not enough to need to updrade injectors?sorry for so many questions but i like to have things figured out befor i get it all in order

 

[VelocitàPaola]

what do you mean by bench racing?

Just what you were doing... asking for concrete horsepower numbers regarding a new part, or collection of parts.

 

[VelocitàPaola]

velocita you said that if you dont add more air( turbo suprecharger or nitrous) there is no need to update injectors. wouldnt a cold air intake and a bigger throttle body and inake add more air? or does it add more air but not enough to need to updrade injectors?sorry for so many questions but i like to have things figured out befor i get it all in order

They don't add more air, they just help it move throughout your engine easier.

 

[NeMiZiS]

I believe the stock injectors are 190cc/min. The TB space is useless.

But I thought adding things like an intake,throttle body, exhaust, etc.
Give better air flow, so you get more air flowing threw the engine?
So only when "forcing" extra air, creates enough of a problem to have to up grade injectors?

 

[VelocitàPaola]

But I thought adding things like an intake,throttle body, exhaust, etc.
Give better air flow, so you get more air flowing threw the engine?
So only when "forcing" extra air, creates enough of a problem to have to up grade injectors?

I'm trying not to get into volumetric efficiency or any of the more complicated subjects for the benefit of newer members... but that's the gist of it.

 

[-dsm4life-]

o i sorry i was just asking if it would be worth me money. i wouldnt wan to spend 200 bucks on something that will help get some extra power out of the car and not get muchif anything at all but again im sorry. thanks for the advice to