On a mildly related note, I remember reading recently about UR600 (?) injectors where each injector in the set had a slightly different flow rate to compensate for the fact that some cylinders run richer or leaner than others in our engines. So if you end up going with bigger injecters you have to install them the right way. Or something.

I have read the cycle duty is too high so you guys think this is not needed for down pipe and high cat all I want is a little more power for track days and autox without blowing up my motor :?:

That's an interesting solution to the problem! But still, if the fuel pressure drops, #3 will be the 1st to starve... but the matched injectors might provide a slightly more balanced fuel delivery, but I'm not sure that it would make much of a difference in performance.

That's doing it the hard way. :lol: I'd rather convert my STi to top feed rails and have a plethora (I said plethora in a sentence!) of injector choices.

I've seen STis put 280 to the wheels with stock fueling. You should always run out of stock turbo before you run out if stock injector.

Not quite, the STi pinks are JDM STi injectors which are top feed and have a higher flow than the USDM STi injectors. (Assuming I have a clue what I am talking about I mean).

And Eric, if you change your injectors you WILL need a custom ecu map, which means the accessport will be useless unless you drive out to cobb for a custom tune ... or they pull their finger out and finish their tuning software so that you can get maps made locally, but that doesn't look like happening until well into next year.

I think it wasn't for performance so much as for the fact that the cylinder that goes lean first is usually the one to have problems. I wish I could find the website of the company selling them.

well if you had your injectors flowed you could install them to where the best flowing one went in the #3 and so on to the richest.

wouldn't a fuel pump and fail rails be a good way to go? :D

Agree here all the way. if all your adding is a DP and a high flow cat you will be fine. for that added safty and to keep your mind at ease just do the parallel fuel rail mod. quick easy and done with it..and the fuel pump will not hurt either. no need to up the injector size or do a reflash..YET!
the only real time you should up your injectors is when you are doing a turbo swap, an injector upgrade and ecu reflash or getting an SAFC is what they ref. to as supporting mods.

Wow! You guys pretty much covered it all....


I love lamp.

and here comes MattR too intoxicate us off topic :lol: :lol:


Pump Group Buy? Install Day? hehehe

ok back on topic! 8)

Seriously though, I would love to get a more definate answer on this subject, I suppose the main question is not which mods to go with, it's in which order to get them. Whether or not the fuel pump is the starting point, I'm not sure. It couldn;t hurt.

1. Fuel Pump
2. Fuel Rails
3. Injectors
4. Intercooler
5. Turbo
6. Dyno Tuning

wow thats a lot of steps :lol:

there has been tons of threads and discussions on the idea that fuel rails may not be needed. I do not know about STi's, but a ton of WRX owners are upgrading without the addition of fuel rails.

Based on all the reading I do at work all day ;) if/when I get an STi the mod path will be:

Step 1: Turboback + custom dyno tune

Step 2: Fuel Pump + injectors + turbo + custom dyno tune

I believe that the STi topmount intercooler is as good as any out there. I would only replace it if I was going to go to a frontmount intercooler. Higher lag but more power potential and no more heatsoak worries. Also, I believe that upgrading fuel rails is overrated, but then again I only have 8 hours a day to do research ;)

Powerwise I don't think it is worth going beyond those 2 steps unles you are going for an all out built block == $$

Honestly a custom suspension setup will make more difference on the track.

I ate a red candle!

actually that mod BAN and I were talking about isn't a rail replacement its just changing the way each rail gets fuel.

Exactly. It's not a good idea to do engine mods one step at a time. As you chenge one system, you need to make sure it still works as a cohesive whole.