stg2lgcy00

iTrader: (23)

What I have:
99RS w/ stock 5spd & 02 usdm EJ205 conversion
Catless uppipe
3'' tbe
crank pulley

My plans for this summer:
Bigger TMIC
Cobb Accessport using CA Stage2 91 octane map (dyno tune eventually)
Perrin fuel rails

Questions:
1. Will the fuel rails help get any more power from the other mods?
2. Will they really help prevent once cylinder from running too hot?
3. Will my car run too rich using them after big TMIC + Accessport?
4. Can I pass the sniffer test if I switch back to stock downpipe and stock ECU? (while keeping the fuel rails)
5. Should I keep the stock fpr?

If anyone could answer these questions for me I would greatly appreciate it. I just don't want to spend the $ on fuel rails if it really won't be worth my while for my setup.

subie OCD

iTrader: (11)

1 - From all my reading, nobody upgrades fuel rails on the wrx....does it help with performance...?...
2-?
3-?
4-?
5-?

IMO a bigger TMIC is a great upgrade for the wrx td-04 turbo! WIth custom tune ecutek, TBE, UP and TXS TMIC, when I floor it at 2000rpms in 3rd gear I get 16-18lbs of boost by 3000 rpms and holds damn close to redline tapering to 14lbs. Only downside is the cost, and you should have a bigger hood scoop to really take advantage.

If I were you, I would get the AP, flash to stage 2, buy the TMIC, then get a protune.

Also FWIW, my buddy with an STi bought the Perrin fuel rails, but thought they were garbage compared to stock and sold them


Hope this helps

Imprezer

iTrader: (9)

1. They will allow you to make power safely. They do not add power themselves.
2. Yes. Quality fuel rails will insure equal distribution of fuel and provide all 4 cylinders with adequate amount of fuel. Remember, your don't have an 02 sensor and knock sensor per each cyliner.
3. That depends on tuning. They do not change the amount of fuel provided. Especially at normal driving conditions.
4. Yes. Same as #3.
5. Yes, in most cases you will be fine. I'd keep FPR stock with VF34 and smaller turbo.

stg2lgcy00

iTrader: (23)

Thanks for the input guys! I will most likley end up getting the AP first of all. Then buy a bigger tmic along with fuel rails and install that stuff all at once. Asap after that is completed I'll probably get good ol moike to tune me up on the hearbreaker hehe.

meilers

I can't imagine going to the cost and bother of doing a big TMIC and fuel rails without also upgrading the turbo, injectors and fuel pump at the same time. The TD04 is going to be totally maxed out. Anything over 16psi in that turbo turns it into a blowtorch, 1500-degree EGTs and no power.

The fuel rails are wasted without the actual fuel pressure to drive them. Upgrading the rails without upgrading the pump and injectors is like putting a 3" downpipe on the car and keeping the mid cat and stock axleback. You would be feeding a fire hose into a garden sprinkler.

Also, fuel rails are not supported by the Accessport's stock maps, nor is the crank pulley. If I was to get an Accessport (I didn't, I did a shop tune with an ECUtek reflash) I would stick VERY STRICTLY to exactly what Cobb specifies.

Just as a note, the shop that tuned my car doesn't bother upgrading fuel rails on either the EJ20 or EJ25 until you are approaching 300-380+ WHP or more (390-460 crank HP). Rich is an extremely conservative tuner and has NEVER blown up a car. He also doesn't do the fuel rails without also doing pump, lines, injectors and turbo as well.

Imprezer

iTrader: (9)

I agree, but installing injectors after the rails are in is super easy, so I would not worry about that. And there is no need for a pump with stock turbo. So if he is just taking it slow and not upgrading the turbo now, there is nothing wrong with getting the rails.

Do do the turbo upgrade you need at least injectors and pump and turbo itself.

So all these mods are good for you and your car. It's just a matter of what you do first.

In terms on not having to upgrade the rails until you hit mucho HP, I say better be safe than sorry. Your motor will NOT blow up if you run crap *** 7 eleven oil for double its lifespan. But would you do it?

Its a known fact that OEM rails do not provide equally adeuate fuel to all cylinders. That is why the compression tests never show identical number on all 4 cylinders. That is why I highly recommend rails to anyone who is planning to make more power than stock. And also, the actual volume capacity of the aftermarket rails is higher. That gives you that extra bit of fuel in case of fuel slush.

So all in all, I think everyone should have rails to be able to sleep well. If you middle name is danger, then by all means wait until 300WHP...

subie OCD

iTrader: (11)

hehe, your rs is going to be a whole new beast after this. Think 50whp and 50wtq! Not to mention your car is much lighter than a wrx. Then its only a matter of time before you start looking for turbo upgrades! Ive only been running this setup for about 3 weeks and Im already looking at the pe1820. Im so impressed with what the stock turbo can do....I really want to see what a bigger one is capable of.

testes1010

I wouldn't bother with fuel rails...most big name tuners don't replace fuel rails until +400whp....

meilers

I agree that rails are a safety margin, and they would indeed help with cylinder 3 problems if he really plans to push it. I just don't see the stock turbo pushing enough air to require the volume of fuel that would actually saturate a bigger fuel rail.

This is all my personal opinion and only worth the digital ink it is printed on, but I think incremental upgrades are dumb :-) and either you drop $3000 and do turbo, injectors, rails, fuel lines, pump, TMIC or FMIC (and engine mounts, clutch, front and rear strut bars, all supporting suspension mods) or you might as well just stick with the accessport and a TBE. The EJ20 is such an incredibly balanced and well-engineered engine from the factory that upgrading any single part of it at a time seems to throw off the balance. Do "holistic" upgrades that change out entire systems at a time, not just nick at it in little jumps and starts.

Imprezer

iTrader: (9)

Holistic upgrades... LOLz... haha... Those are teh best, mang!

stg2lgcy00

iTrader: (23)

I mainly wanted the rails for the saftey reason of even distribution. I'm not planning on upgrading the turbo anytime soon, not even next year. I'm not just gonna drop 3 grand on a full out setup, I already did that in a way by getting my engine swap which cost me enough already.

With around 108K on my stock driveline I need to think about that rather than strapping a vf34 on my car. Eventually I want to pick up a stock rs tranny and a rear lsd from a 00-01.

So would I really not be able to run a AP Stage 2 map while having a crank pulley and fuel rails?

meilers

LOLz? Is someone else logged in to your account?

Even if you LOLz, you know what I am talking about. We've all seen someone with a WRX, STI or RS who has done a bunch of low-budget/homebrew changes to the car and then complains that they have a rough idle or crappy gas mileage or that they still can't beat their older brother's SRT-4. I'm not saying that the original poster was going to do this, but dropping a shorty intake, a full-atmospheric BOV, an eBay catback, a grounding kit and a manual boost controller on a Subaru is a pretty typical upgrade path for the budget minded -- and a total disaster. Little junk upgrades here-and-there is NOT the way to handle a Subaru engine or automobile.

You know as well as I (and most others on this forum) that all the systems of these engines are intrinsically linked and well-balanced from the factory. I'm just encouraging him to not leave weak links in the chain, or to wait until he can change all the links in a given chain at the same time. I don't think a stock EJ20 with the stock turbo and fuel pump has any serious fuel distribution problems; most people who toast the factory engine do so by going past redline (the infamous 5th-to-3rd downshift on the highway) or running 19psi of boost with a manual boost controller. The factory tune of the car is so rich the cylinders are soaked with fuel. I *gained* 3 mpg (30-50 miles per tank) and 70 horsepower by reflashing the ECU and adding a turboback w/ hi-flow cat, and yet my injectors are at 78% duty cycle (I made certain the tuner didn't take them over 80). I was able to lean out the car that much and still get no detonation or ping, so there is a lot of safety margin in the stock engine setup as it is.

ride5000

where'd you come up with that bit of misinformation?

RysingSun808

dont even get fuel rails unless you planning to get a bigger turbo...

meilers

If we're discussing the TD04 in the 02-03 bugeye WRX models, that info comes from an engine builder and tuner who's been working with turbo Imprezas and Legacy models from 1997 on, and has built 400whp STIs (running 91 octane) since they arrived on US shores -- he's had 2 cover cars for Sport Compact Car in the past 2 years. If the inlet pressure on the turbo cold side exceeds the CFM flow of the hot side, you get drag on the vanes and no more power. 300cfm is the rating for that turbo, I believe...

I also know this from personal experience. I'm tuned to 16.1 PSI with an ECUTek reflash and tune; a friend of mine is tuned to 18.5 with an EBC (both 02 WRX models, stock turbos). I put down 10 more HP on the same dyno (Dynojet AWD) and my EGTs are 400 degrees cooler. His boost curve with the EBC looks just like mine until 17 PSI, then it spikes up and his hp/torque falls right off a cliff. One data point does not make a trend, of course, but his dyno chart seems pretty clear.