engine build recommendations

[Zodiac]

ok so as we get closer and closer to the release of the 818 I really need to start ordering stuff and putting things together. I'm going for about 350-400whp myself. Probably not all at once but the engine internals I for sure want to get done so I don't have to worry about taking the engine out and apart later down the line. I've read and looked up a lot which has helped me make out my list below but still have a few questions.

Engine
• GSC S1 cams w/ upgraded valves and retainers
• ARP Head and Case Bolts
• OEM 79mm crank
• Manley H-Beam Rods w/ Manley 99.5mm STD pistons
• ACL Race bearings

Other
• Blouch TD05H-18G-XT Turbo w/ 7cm housing
• ETS Top Mount Intercooler
• Perrin Inlet Hose w/ Intake Filter
• Deatsch Werks 850cc Fuel Injectors
• Walbro Fuel Pump 255Lph
• AEM Wideband o2 sensor
• Gruppe-S Unequal Headers w/catless uppipe

So givin all that I'm mainly wondering if I really need to go with a nitrided crank or am I ok with the OEM one (150k miles on donor or new OEM)?? Also the Blouch Turbo comes with a turbine housing options of 7cm, 8cm, or 10cm so really not sure which I should go for. Block is getting honed and probably decked but do I need to get the heads ported? And any other help is greatly appreciated.

Hopefully this could also help anyone else looking for answers to build question/decisions.

[fateo66]

There is alot of debate on whether the nitride treated crank is any better then the older one but either way starting in 2013 subaru came out with its newest cranks (heat treated) which is better then either previous versions.

As for the fuel pump I would hold off on buying it until we know more details on the gas tank. Will it have in intank or inline pump? Will it accept the same style intake pump?

As for the turbo, personal I would go for the 7cm version. It wont make the same peak power as the 10cm but it will spool alot faster and be more usable in a car that weighs half as much as what everyone else uses it in.

[UFfitz56]

I am wondering why you would need a fully built motor for an 18g? Stock EJ257 can easily handle an 18g. But yea I would also go with 7 or 8cm turbine housing.

This is my first post but I have been lurking here for awhile and have a lot of experience with EJ motors (08 sti with 420awhp).

[UFfitz56]

Also do you want UEL headers mostly for sound? Completely understand if you do but EL headers would definitely give you more power and slightly quicker spool.

[Zodiac]

Yea that's right still not sure on the fuel pump situation so i'll be holding off on that. As for the crank guess I'll do a bit more research on it before I pull the trigger but from the sound of it I should be pretty safe with the stock non-nitraded unless I really wanted to go higher is whp. Which makes going for the 7cm turbine housing an easier choice also. Not really in need of top end with such a light car. Oh and yea I'm going UEL mostly for the sound. still a upgrade from stock and I have read the gain difference is pretty small. But yea having that rumble is this will definitely put a smill on my face haha.

As for cleaning the engine it has high miles so better safe than sorry on that. The stronger internals should also help with longevity from what I have gathered and with Manley not being as expensive as the others but still having the great reliability that is what helped me choose those. And while I have the entire engine apart adding the ARP bolts is a small price to pay for some extra piece of mind.

[bnr32jason]

Interesting, different strokes for different folks I guess.

One of the seondary reasons I'm so happy to be using a twin-scroll turbo is because it uses an equal length header which gets rid of that Subaru boxer rumble. Sounds like it's broken to me, LOL.


On the topic of the fuel pump, doesn't the "parts required" list say we need to use the fuel pump from the donor car? Wouldn't that suggest it's going to be an in-tank setup. I would think a Walbro 255 and a decent adjustable FPR would be all you would need, maybe not even the FPR.

[Zodiac]

haha yea basically. And as for fuel pump yea it does but I think I will still hold off just in case changes come up something.

[longislandwrx]

Only can speak on what I know but...

Go with a plx wideband, I think you'll like it better over the AEM.

for fast spool, go with the 7cm housing... the 10 will give you better top end but likely be too much too late on the 818. I'd go for big midrange and fast spool so you don't overwhelm the tires with huge top end power that comes on too hard.

I think you can do without the rods, and crank... pistons should be plenty, unless the crank is scored or you are trying to use a different rod to change the engine dynamics.

make sure you get an sti oil pump, or a new one at the very least. I would use some of that engine money on an oil cooler as well.

[BrandonDrums]

There's actually more debate on weather the heat treated crank is better or not either.

http://forums.nasioc.com/forums/showthread.php?t=2394938

I had this same question after a plague of rod-bearing issues and ultimately the guru of all guru's after much discussion and research say the crank treatment doesn't matter in preventing rod-bearing failures but really just limits the damage on the crank when they do happen. The crank can be diamond coated, that doesn't make it frictionless. If you have junk or a lack of oil between the bearing and the journal, the bearing will still fail.

Some of the other guys found that the nitrided crank actually had an inferior alloy compared to the previous non-coated versions. The coating was to make up for a cheaper softer metal. The jury is still out on the heat treated cranks in terms of bearing failures but they can resist damage from a failure and the heat-treated cranks can be polished and ground down without loosing the effect of the treatment while the nitride cranks can't.

I hope that helps.

Also, for what it's worth, thanks to the great (and by great I mean terrible) engine geometry of the EJ257 engine, popping in forged pistons will prevent a ring failure but can sometimes result in reduced compression from worn out cylinder walls. This takes a good 60-80k to happen and can be prevented by religiously using an engine-block heater and letting the engine warm up before driving it to reduce the amount of time you have with piston slap.

If you want the engine to last longer than this, getting piston sleeves installed can be a worthy investment.

[Zodiac]

Ah ok so yea 7cm turbine housing would be a much better choice

And for the crank since it's such a debate about the 2 then that just shows the oem one has merit in itself so I'll be keeping the one I got since it's looks in new condition still.

As for the oil pump yea I plan to get a STI version of that as well a new water pump while I'm at it. Should I invest in a Killer B oil pan/baffle/pickup kit as well?

[fateo66]

There's actually more debate on weather the heat treated crank is better or not either.

http://forums.nasioc.com/forums/showthread.php?t=2394938

I had this same question after a plague of rod-bearing issues and ultimately the guru of all guru's after much discussion and research say the crank treatment doesn't matter in preventing rod-bearing failures but really just limits the damage on the crank when they do happen. The crank can be diamond coated, that doesn't make it frictionless. If you have junk or a lack of oil between the bearing and the journal, the bearing will still fail.

Some of the other guys found that the nitrided crank actually had an inferior alloy compared to the previous non-coated versions. The coating was to make up for a cheaper softer metal. The jury is still out on the heat treated cranks in terms of bearing failures but they can resist damage from a failure and the heat-treated cranks can be polished and ground down without loosing the effect of the treatment while the nitride cranks can't.


When I was talking about cranks I was not inferring that it would be better for not spinning bearings. A spun bearing is a spun bearing and has very little to do with the crank.

But a heat treated crank will be stronger then a non heat treated crank.

[papajon1000]

I am going to get a killer b pickup and baffle. It seems like cheap insurance for me to pay the $270 to keep the $4,000 + engine going. It's just one less thing I will have to worry about failing. I know there are plenty of people running fine on the stock pickup and windage tray (I currently am lol) with no problems.

I also noticed your original list didn't include tgv deletes. I would suggest those as something to add to your list.

Just my $.02
Jon

[Zodiac]

yup I would definitely feel better spending a little more now than a lot more later on. Oh and yea forgot to add getting the TGV deletes. Most likely Grimmspeed maybe.