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Old 03-24-2006, 12:12 AM   #1
bksalgado
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Default EJ257 Engine Reliability

I've searched for the past week to find answers to my question, but i've been just getting more and more confused.

I have an 06 USDM STI and am currently ordering parts. I just ordered a UTEC, perrin intake, APS BOV, TurboXS uppipe, TurboXS downpipe w/ cat adaptor, and a JIC cat-back. From what i've been reading i also understand that i should upgrade the fuel rail, pump, and injectors as well. I plan on getting the my EJ257 to around 350-365HP now and probably around 400-420HP in a year or so with a new turbo. My question now is about the engine itself. I've read many threads on pistons, rods, engine block, etc.. I understand that the USDM STI have a bunch of cast parts but i can't find a reliable source about the limits of the stock STI engine so..

What would i need to upgrade in order to run in the 350-420HP range smoothly and safely and w/o detonation, piston slap and all that other stuff. I'm thinking about forged pistons, rods, cams, crankshaft, cylinder head but im not sure.

If i should need to upgrade pistons, should i get stock bore, .5mm, or 1mm oversize then have a shop fit them into my engine?

And another question, when would i need tumbler deletes?
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Last edited by bksalgado; 03-24-2006 at 09:38 AM.
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Old 03-24-2006, 01:35 AM   #2
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you need a good tune, and some good gas.....and the parts of course... but tuning I feel is the most important.... And not some homebrew tune by yourself.... a tune from a professional...
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Old 03-24-2006, 02:00 AM   #3
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Old 03-24-2006, 02:45 AM   #4
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Tumbler deletes is more for power, and won't be necessary until you get much higher than your power goals.

Until you consistently break 400whp, stock is fine. 400+, just get forged pistons and ARP head studs. That should hold you fine to to atleast around 450-500whp.
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Old 03-24-2006, 09:32 AM   #5
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what about the fuel system. Since i'll be increaseing the exhaust and intake airflow, i'm going to probably make the UTEC run more fuel to avoid detonation. With an intake, uppipe, downpipe and cat-back, would i need to upgrade the fuel rail, pump, or injectors or all three?

What about pistons, im thinking of CP Forged, and should i get oversized and have a shop install them or standard and drop them in?

And when i change the pistons, should i change the piston rods, crank, cams as well?

Last edited by bksalgado; 03-24-2006 at 09:39 AM.
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Old 03-24-2006, 10:06 AM   #6
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Just a quick note...you don't really need the TXS uppipe since the STi has a catless uppipe already. The fuel rails should be fine as well as there are some 600HP STis running the stock fuel rails without issues. You can save that cash for other things.
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Old 03-24-2006, 10:10 AM   #7
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Also, if the numbers you are quoting you want to achieve are crank horsepower then you are good to get into around the upper part of your range with the stock / ported VF39 turbo and without touching the bottom end. If you are talking wheel hp then you will need a turbo upgrade and supporting mods earlier on to safely make those numbers.
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Old 03-24-2006, 10:14 AM   #8
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Quote:
Originally Posted by jigga
you need a good tune, and some good gas.....and the parts of course... but tuning I feel is the most important.... And not some homebrew tune by yourself.... a tune from a professional...
^^^^^What he said too!
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Old 03-24-2006, 10:15 AM   #9
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H2O/Meth is a great idea.
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Old 03-24-2006, 10:23 AM   #10
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You don't need larger injectors with bolt ons, like exhaust and intake...

But as stated, you'll NEED a tune... a real one.

With all the parts you'll get, the only thing you'll choose to do later on if you go for a larger turbo is: Turbo, Injectors, fuel pump, and maybe a larger TMIC of FMIC...

I'd also recommend Mahle pistons (especially for a daily driven motor)... and if you're gonna use a USED block, to have the cylinder walls rehoned. Read The FAQ's on here and other posts, because there is a lot of what you asked in very recent posts.
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Old 03-24-2006, 10:29 AM   #11
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Quote:
Originally Posted by bksalgado
I understand that the USDM STI have a bunch of cast parts but i can't find a reliable source about the limits of the stock STI engine so..
It's probably best to start accepting the fact you will not find a good, reliable source for this information. Choose to be frustrated or move on.

I'd say, on average, a person tuning their own UTEC has a much higher chance of popping their motor.
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Old 03-24-2006, 10:47 AM   #12
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I'll cancel the order on the TXS uppipe. I know the upgrades that i've ordered will get me in the 350whp area (I think..). So for mechanical safely around the 350whp range, I should just need pistons, head studs, have the cyliner walls rehoned, and have a professional tune right? When i replace the pistons, should i replace the rods too?

When i choose to get in the 400-420whp range via larger turbo i should just upgrade the fuel pump and injectors, right? j/w b/c im not sure of the max boost the stock EJ257 block and crank can take.

Am i missing any more needed support mods?
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Old 03-24-2006, 11:08 AM   #13
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Quote:
Originally Posted by bksalgado
I'll cancel the order on the TXS uppipe. I know the upgrades that i've ordered will get me in the 350whp area (I think..). So for mechanical safely around the 350whp range, I should just need pistons, head studs, have the cyliner walls rehoned, and have a professional tune right? When i replace the pistons, should i replace the rods too?

When i choose to get in the 400-420whp range via larger turbo i should just upgrade the fuel pump and injectors, right? j/w b/c im not sure of the max boost the stock EJ257 block and crank can take.

Am i missing any more needed support mods?
Factory EJ257 rods are quite strong - I'm having mine shotpeened for a slight improvement in durability, but its not a necessity. I'd say you'll be fine with the factory rods. If you're going to do pistons I would recommend doing rod/main bearings at the same time as they are not that expensive and you'll already have the case split.
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Old 03-24-2006, 11:09 AM   #14
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The injectors can be max out on the stock turbo without too much effort, so yeah, you'll need new ones.
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Old 03-24-2006, 02:04 PM   #15
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Quote:
Originally Posted by bksalgado
I've searched for the past week to find answers to my question, but i've been just getting more and more confused.

I have an 06 USDM STI and am currently ordering parts. I just ordered a UTEC, perrin intake, APS BOV, TurboXS uppipe, TurboXS downpipe w/ cat adaptor, and a JIC cat-back. From what i've been reading i also understand that i should upgrade the fuel rail, pump, and injectors as well. I plan on getting the my EJ257 to around 350-365HP now and probably around 400-420HP in a year or so with a new turbo. My question now is about the engine itself. I've read many threads on pistons, rods, engine block, etc.. I understand that the USDM STI have a bunch of cast parts but i can't find a reliable source about the limits of the stock STI engine so..

What would i need to upgrade in order to run in the 350-420HP range smoothly and safely and w/o detonation, piston slap and all that other stuff. I'm thinking about forged pistons, rods, cams, crankshaft, cylinder head but im not sure.

If i should need to upgrade pistons, should i get stock bore, .5mm, or 1mm oversize then have a shop fit them into my engine?

And another question, when would i need tumbler deletes?
Even though it saves time and labor to have rods, cams, etc done on any engine work, it's not necessary for your goals.

With your current setup, you'll get to 350wtq with a good tune (really high, maxed out tune), but your HP goal probably won't be there. Only a bigger turbo is going to safely get you to 350whp.

The two easiest internal upgrades that will get you to the 500whp range is forged pistons and ARP headstuds. You won't need more than that for your current goal. You are also building to what looks like a bolt-on turbo setup. Keep in mind that rotated setups have their own intake, dp, and other parts, so you should seriously consider what turbo you want before getting all the other "plumbing".
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Old 03-24-2006, 05:19 PM   #16
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Yeah, I'm just planning on getting all the safety/support upgrades and the "plumbing" so i can just drop in a turbo later. Any recommendations on a turbo that would get me in the 350-400whp range?
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Old 03-24-2006, 05:29 PM   #17
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How about the new Helix one that is coming out?? The RR500. I have read a little on it. It sounds like a winner.
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Old 03-24-2006, 06:09 PM   #18
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Quote:
Originally Posted by epaplia
How about the new Helix one that is coming out?? The RR500. I have read a little on it. It sounds like a winner.
It does. A FP Green or SZ49 will get you there too. Deadbolt has a new Turbine wheel coming out that's suppose to flow 20% more air than their fatboy wheel! I'd check that guy out too.
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Old 03-24-2006, 10:22 PM   #19
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Quote:
Originally Posted by bksalgado
I've searched for the past week to find answers to my question, but i've been just getting more and more confused.

I have an 06 USDM STI and am currently ordering parts. I just ordered a UTEC, perrin intake, APS BOV, TurboXS uppipe, TurboXS downpipe w/ cat adaptor, and a JIC cat-back. From what i've been reading i also understand that i should upgrade the fuel rail, pump, and injectors as well. I plan on getting the my EJ257 to around 350-365HP now and probably around 400-420HP in a year or so with a new turbo. My question now is about the engine itself. I've read many threads on pistons, rods, engine block, etc.. I understand that the USDM STI have a bunch of cast parts but i can't find a reliable source about the limits of the stock STI engine so..

What would i need to upgrade in order to run in the 350-420HP range smoothly and safely and w/o detonation, piston slap and all that other stuff. I'm thinking about forged pistons, rods, cams, crankshaft, cylinder head but im not sure.

If i should need to upgrade pistons, should i get stock bore, .5mm, or 1mm oversize then have a shop fit them into my engine?

And another question, when would i need tumbler deletes?
Oh man, you do seem a bit confused, heheh. Itís OK; weíve all been there. I really wish I could find some threads on this because I know that I have personally answered this question at least 3 or 4 times before in threads but here goes again. Iíll copy some of it over from another post of mine that I found.

I would say that if you're making over 450-460 CHP reliably and you plan on having your motor long term, you should be looking at a built motors (pistons and bearings at the least). In our experience, it seems that 90% of the blown STi motors (weíve seen over 2 dozen now) are caused by bad pistons or bearing failure. This is precisely reason why our Stage 1 short/long block package upgrades the stock STi pistons to forged units while also uprading the bearings to coated race units. These are really the two weakest points of the STi block. This package is rated for 535CHP. Can the stock block take more? Certainly, but I wouldn't recommend it if reliability means anything to you. This probably the reason why you hear about a lot of big power stock block cars that then seem to mysteriously vanish...

Another way to look at is if you have a smaller bolt-on turbo (FP Green, TD06-20G, SZ49, VF34 etc.) and you run it on pump gas only, the stock block will be more than reliable. Running these on 100 octane all the time will start to test the limits of the stock block. If you go rotated or you run anything with a 55 lbs wheel or larger (FP Red, SZ55, GT30R, GT35R) then you should start looking at a built block.

As far as your modifications, I would say that you have some that are extraneous but Iím sure you will get a 100 different opinions from 100 different people. We prefer reflashing solutions (Cobb AcessPort w/ Protune or ECUTEK reflash) to piggybacks for daily driven cars because piggybacks are not as seemless as a reflash and donít offer as much control in some regards. We tell all of our customers to avoid intakes on Subaru motors because they lean out your AFRs unsafely (unless tuned for) and Subarus are very very sensitive to MAF location. If you run an aftermarket turbo that requires a big MAF then go for an intake. Otherwise, avoid it and go with a drop in filter. The same can be said for the stock recirculating valve since it will hold up to about 23 PSI reliably. If you go aftermarket, just make sure to get BOV that can recirculate completely. Otherwise you risk backfiring, stumbling, or having your tuner tell you to come back another day because your BOV can't hold boost because it is leaking. The uppipe actually isnít a terrible idea because it has a bigger diameter than stock so it will give you better spool up. When coupled with an aftermarket header, it will make good power. Although youíll be running 95-100% IDC with just a TBE and a tune, you can probably wait to do injectors and a FP until you upgrade your turbo. You do not need to do the fuel rails until youíre pushing major power (550+ CHP) and doing them at all is debatable.

If youíre looking to make 350-370 CHP as cheaply as possible, here it is:

-Turbo back exhaust
(-Headers are a cheap and easy way to push past that but are highly debated even though they make good power)
-Custom tune

If youíre looking to make 400-420 CHP as cheaply as possible, add:

-FP Green / TD06-20G / SZ49
-740-860cc injectors
-Walbro 255L fuel pump
-Big MAF
(-FMIC is a good idea for consistency and a bit of extra power but is not necessary. Youíll need some sort of upgraded IC.)
-Retune

You will not need a built block for any of those mods unless you run C16 100% of the time. You do not need TGV deletes unless you run a 3Ē Green or Red or something of that size. As already discussed, forged pistons and coated bearings are good but not necessary for your desired power levels. STi rods are good for over 600+ CHP but if you over-rev them at the power level, theyíll stretch out and break. An upgraded crankshaft is good if youíre looking to make over 535+ CHP but again, itís not necessary for your power levels. I would leave your heads (cams, port and polish) alone as the STi heads are quite good and the power gained per dollar spent ratio is very low. A modification like meth / alky / water injection is much more worthwhile. Of course good balancing of the rotating assembly is desirable for any built motor.

Most importantly, try to keep it simple. Remember that the less modifications there are, the less points of failure there possibly are. Work closely with your tuner to see what he or she is comfortable doing and remember that a good tuner is key. Sorry for the essay and thanks for reading.

-Geoff

Last edited by Gruppe-S; 03-24-2006 at 10:31 PM.
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Old 03-25-2006, 10:07 AM   #20
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^^^Good post...
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Old 03-25-2006, 10:45 AM   #21
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thanks guys.
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Old 03-25-2006, 12:05 PM   #22
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i think you'll be looking more towards about 305-320WHP you wont achieve 340+HP unless you got meth injection, all those bolts on are great for the STI..good tune and good gas is key also
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Old 03-25-2006, 10:16 PM   #23
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Quote:
Originally Posted by Gruppe-S
I would say that if you're making over 450-460 CHP reliably and you plan on having your motor long term, you should be looking at a built motors (pistons and bearings at the least). In our experience, it seems that 90% of the blown STi motors (weíve seen over 2 dozen now) are caused by bad pistons or bearing failure. This is precisely reason why our Stage 1 short/long block package upgrades the stock STi pistons to forged units while also uprading the bearings to coated race units. These are really the two weakest points of the STi block. This package is rated for 535CHP. Can the stock block take more? Certainly, but I wouldn't recommend it if reliability means anything to you. This probably the reason why you hear about a lot of big power stock block cars that then seem to mysteriously vanish...
Geoff,

Would you guys say that oil viscosity had anything to do with the bearing failures in the cases you've seen? I would hope that people running those types of power levels and want long term reliability aren't using basic 5W30 for proper lubrication (IMHO) but I know it's possible.

BTW...excellent post even for us not so newbies...

Dtech
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Old 03-26-2006, 06:21 AM   #24
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Default the threshold vs. peak boost thing...

Quote:
Originally Posted by Gruppe-S
...The uppipe actually isnít a terrible idea because it has a bigger diameter than stock so it will give you better spool up. ...
Thanks for the 'essay.' I had one question about the UP and its relation to spool-up. Is there a trade off here as a wider diameter UP would yield a deceleration of the EGs?
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Old 03-26-2006, 08:22 AM   #25
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Quote:
Originally Posted by Gruppe-S
Most importantly, try to keep it simple. Remember that the less modifications there are, the less points of failure there possibly are. -Geoff

so would this go to mean then that built engines are less reliable than oem?
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