legacycentral bbs

Im not looking for extremely detailed write ups or tuning methodology. Rather Im interested in the path some of you have taken to get high amounts of power. For example, here is my rough idea in the order of need as power increases.

Intake changes (panel filter or CAI)
Exhaust, from the turbo back in 2.5 or 3 inch
Instramentation (A/F, Boost, EGT)
Intercooling (water or air)
Boost control
Fuel cut work arounds
Fuel system upgrades/Fuel management electronics
Pre turbo exhaust components (headers/up-pipe)
Larger turbo


Basically for the most part I have ignored any turbo discussion since I owned 3-4 NA subaru. Now that my engine swap is about to take place I want to write up a detailed plan and budget for what is needed. Consider for the moment that Im a total newbie. My turbo experience comes from my supra, my knowledge to subaru turbo tuning is only general to any turbo vehicle. I know I can benefit from everyones experience.

Thanks for your suggestions!

edited for suggestions

Your list looks a lot like the one i took so far, but i would defitely ad a "Fuel system upgrade" just before "Fuel management electronics"

and, instrumentation, A/F is good, but EGT is definitely preferable, precise, usefull.

and, fuel-cut workaround at the same time as the boost control


Your list is a nice idea !

Totally forgot about EGT!

What types of fuel upgrades are needed and at what level? Id guess first step would be uprated flow pump followed by larger injectors?

When does fuel cut become a problem?

At what level does the stock injector start running about 75-80% duty?

Honestly, if you do any fuel upgrades....mainly injectors, and possibly pump.....you really need some additional management since the stock ECU is designed to run on a certain flow rate injector.

EGT's are good instruments. if you plan on tuning with your guages then Id get a good EGT and if you really want an air/fuel guage, then get a wide band guage and probe, the usual "wire into the stock O2 sensor" is absolutely worthless for any real tuning. Your list is pretty complete though. Piggy back electronics are good for mild improvements, but If your looking for real power gains (safely) then I'd go for a standalone ECU such as the autronic and have it intially set up by a shop. Then You'd be able to fine tune the thing with a laptop once you learn the fine points of performance tuning. In this hobby you can make as much power as you like, its just the amount of money your willing to spend is usually the limiting factor.

Ciper: Fuel Cut is programmed at 13 psi for more than 8 seconds (don't quote me on the the exact time but IIRC that what it is around)

Mark,

our injectors are rated 380cc/hr rigth ? if so , they reach 90%Duty cycle at 16psi.

Wouldn't injectors be rated using CFM? Considering different turbos blow more or less CFM. Therefore the injector duty cycles on various turbo's would be different at the same psi. Do I makes sense, or is this jiberish?

Mark,

injectors are rated in cc/min.

The 380 number sounds close, but the units are definitely cc/min.

Looks like a good list to me. I would add that if your looking for bang for the buck, you can go Saab IC ~$40, MBC homemade grainger valve ~$10, Autometer EGT and Boost gauges ~$150. At 10-11 psi your under fuel cut and have about 200 crank hp. I'm not sure how much a better exhaust helps the Legacy (they are 10 year old cars) but on MY WRX I did not change the exhaust. I think a cheaper mid point would be to start with a downpipe, then spring for a mid and axel back later. Good luck these cars sure do wake up with a little extra boost!

oops ya not cfm, what was I thinking , I meant injectors are rated using the amount of volume they pump. i have no idea why I said cfm. Sorry if i confused anyone.

Mark,

fyi 360's are the stock injector size

My personal map to horse.

1. K&N Air filter - that's for any car

1a. Instrumentation - Do this early on, most likely you bought the car used and you have no idea what it's doing... I couldn't stand going WOT until I had some gauges on mine.

2. General tune up and replacing parts (most forget about this step)
-Get the engine running perfectly first
-I would include Ignition stuff here: Diamond coilpack, Grounding Mod, 8mm wires, etc...

3. Intercooler - Engine runs much safer detonation wise AND more horse

4. Full Exhaust - 2 cats with 150k miles on a horrible downpipe design must go
-Straight pipes and # cats are personal preference

5. Turbo and/or Remappable ECU - depending on cash flow, some say the stock ECU can handle a slightly larger turbo intercooled just fine

6. Fuel delivery - You must have ECU by now for Injectors & Fuel Pump.

7. Extra Cash flow goodies - Headers, Displacement, Internals, Nitrous (small shots need only apply), Port & Polishing, Additional time tuning ECU, etc...

Bump! I would really like to know at what point upgraded injectors are recommended and at what point a larger fuel pump is recommended in terms of psi and/or chp

I would say now on the pump. My car felt better at high rpm after I changed to a new pump. It might just be me but I wanted to know it was good before I raised the boost. I don't know when you need to upgrade but do you think the stock pump is still putting out what it was when it was new? Your injectors are good to a lot more than some people will say, I think it's the ECU that can't keep up. Look at how far the Liberty guys go on stock (same as ours) injectors. I know there are some getting more than 200hp ATW. How much power are you going for?

I'm not sure how far i'm going to take it. I just want to know so as I go I know when to plan for these parts. I was thinking about maybe doing the 255 fuel pump since it's pretty cheap some time soon but the injectors seem pretty salty that i've seen so I'd probably have to plan for them.

Wait, Liberty RSes have the same injectors we do? I thought they were 440cc or something.

It strikes me as weird that Subaru would put the same injectors on engines with such different power outputs.

No...I'm pretty sure the early liberty's with EJ20G's had the 440cc injector. Thats not the same as the EJ22T's injectors.
Micum

No they get 380cc injectors. I just got on the rsliberty forum and looked it up. And this talk of how much psi they are good to is bull. On a hot day? a cold day? what's been done to your exhaust? intake? stock turbo? VF23? what about a VF22? All these things can make a (huge for the turbo) difference in the answer. I got more power out of my new turbo at "stock" boost, you could feel it. I'd say the VF23 will make more than mine. And that takes more fuel.
Now I'm at 16psi and I can light up two tires off the line. (no lsd ) It feels like a mid 14 sec car, and faster than my WRX through third.