Fuel injectors

[ratchetgmc]

I recently purchased a 95 camaro 3.4 liter v6. Previous owner has installed the fuel injectors out of the 3.8 liter v6 motor as a performance modification. Is this a legitimate performance mod or is this just a rich running motor wasting gas.

[viperh]

Originally Posted by ratchetgmc

I recently purchased a 95 camaro 3.4 liter v6. Previous owner has installed the fuel injectors out of the 3.8 liter v6 motor as a performance modification. Is this a legitimate performance mod or is this just a rich running motor wasting gas.

Did he do anything else to allow more airflow? port and polished intake and CAI or anything of the like?

[Mr. Luos]

I wouldn't call it a performance mod.

Might have been a maintanance thing though.

[ratchetgmc]

No. no other mods were done. And yes, he told me that it was done purely for an increase in performance. There were no problems with the vehicle. Was told that his intention at the time was to keep the car; and that this was the first of many things he had on his list. Next was the cold air intake, then a free flow exhaust maybe including headers. He told me he read a performance article explaining this injector mod as an increase in performance. So what i am hearing hear from first reply is that this increase in fuel needs to be offset with an increase in air. Is this correct? Cold air intake; k & n filter, etc.

[ikeyballz]

i believe..the injectors will give you a bit more power.. but not much..for the price, anyways...

i read an article where all they did was change injectors (on a V8..) and it gained +20 on some rpms.. and im sure thats not true for all engines, some that already get extra prolly might even lose hp...

guess it depends on your car.. but if you're gonna get cai, etc.. keep em! :]

new injectors are always good.

[Whoaru99]

Unless there is something specific about the injector that is better for spray pattern or atomization (and assuming the others were not defective), there is not really a good reason to expect a performance increase in this situation.

The computer is still running the show and it merely controls the injector duty cycle to satisfy the demand.

It should run neither richer nor leaner unless the range of operation is outside of the fuel pressure and or injector capacity. If the injector is larger than than the original, the ECM recognizes more fuel and reduces the injector duty cycle to bring things (air/fuel ratio) back into balance.

[ratchetgmc]

Thank you to all that replied. Whoaru99 that explaination sounded right on time. You sound like you know what your talking about.So these new injectors will probably only come into play with increased air and above the limits of the old injectors.

[Mr. Luos]

Yes and no.
The ECU goes on percentages. The computer needs to be told of the larger injectors. In this case though, it is probably okay as the change is very minimal.
If anything, I would think a decrease in performance would be seen from a slightly larger injector. Again though....very little. It would run richer.
BUT...with the injector sizes being so close, the ECU should be able to make up for most of it.

Injectors aren't a performance mod in my opinion. It is a required mod when going to big power, but just because the more power you make and the more air you move...the more fuel you need.

[Whoaru99]

Originally Posted by ratchetgmc

So these new injectors will probably only come into play with increased air and above the limits of the old injectors.

Yes, mostly correct as Mr. Luos has said.

Without knowing what the difference in injector rating is, it would be pretty hard to say where this might make a difference in conjunction with other mods.

But, on a stock engine, merely changing the injector to a (assuming) slightly larger size is really of little benefit. I don't know the mechanics of the 3.4L engine, but a more effective approach probably would have been to keep the stock injectors and tinker with the fuel pressure if you needed just a bit of fine tuning in conjunction with some simple mods.