New GT owner with injector question

[HerbaJonny]

I recently picked up an 07 GT with 120k on it. For mods it had Cobb intake, Cobb access port v2, a cheap 3' cat-back exhaust and a lightened flywheel.

 

So far in the last few months of owning it I installed a Cobb short-shifter (stage 1+) with new front/rear bushings, and added a Cobb downpipe.

 

A mechanic buddy of mine who's a master Subaru tech is now helping me isolate a major problem that's come up. It's showing me that all 4 cylinders are mis-firing.

 

We checked the coilpacks, plugs, changed the front o2 sensor, checked the MAF sensor and have determined that the valves were tight.

 

Currently he's got the motor out and fixing the valves. When he pulled the motor he noticed something weird with the injectors. It appears the 3 of them are stock and 1 of them is from an STI. Not knowing the history of the car, I'm looking to just get new 4 new injectors to eliminate any possible issues in the future.

 

I'm on Deatschwerks website and with the rebate it's not that big of a difference (price-wise) to go from 565cc injectors to 650cc. I'm NOT planning on increasing the size of my turbo in the future or doing anything else to the car to increase the power production than what's already done.

 

So my question is, would I just be wasting $20 to go with the larger injectors? Will it do anything (good or bad) if I went with them?

[ehsnils]

Looks like a good idea to get a matched set of injectors.

 

It also depends on how you plan to drive the car and if you are doing intake/exhaust mods to improve the air flow on stock turbo or plan to upgrade turbo if you want to replace the injectors.

 

With the bigger injectors you may also want to check/upgrade the fuel pump to be sure that it can cope with the full flow if you come to that situation. Not urgent though.

 

A downside with larger injectors is that the opening time at idle have to be shorter. In theory that means that the fuel mixture at idle can be harder to get tuned right by the system.

 

And as noted in other threads - when you work on the engine you can as well replace the donut gaskets at the intake manifold to avoid air leaks. Stock are black, new are orange and stock ones have a tendency to cause some problems at idle, and it may be that they are the culprit.

[Max Capacity]

www.tuningalliance.com had/has a special going on...

 

http://legacygt.com/forums/showthread.php/injectors-and-fuel-pump-sale-252685.html

 

PM Brian and tell him I sent you.

[coldsoda]

if you put any other injector in the car other than OEM, you'll want to get a pro-tune. a new fuel pump is always a good idea. you can always go bigger and dial back to run a lower duty cycle, but if you go with small you're stuck with that. I'd go bigger, personally, and get a proper tune once put back together.

[Kemptemp4]

If all 4 are misfiring, you most likely have a vac leak. Especially if all the codes popped up at the same time. Take your tmic off and check the vac lines that run from the t connector on both ends of the three hoses. If that ends up being it, zip tie em back on. Seriously a 10 min. Solution

 

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[Kemptemp4]

Lol nevermind, only reaf top part of your thread... still a good thing to check for though!

 

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