Looking for suggested parts to build a short block

Starting with an EJ255 block. Should I have it machined or new EJ257 block?

 

 

My goal is 330-350 WHP on e85. I will be converting to top rail 1000cc injectors.

 

 

 

What do you recommend for:

 

 

Forged Pistons?

Rods?

Bearings?

Crank?

 

 

Part numbers are appreciated. Thanks.

330-350whp is right about the maximum you'd want for a stock bottom end; with a good tune, you can keep it reliable for years to come. Above 350whp it becomes a bit of a bottomless pit depending on your long term goals.

 

You could just do pistons to be safe, as typically those stock ringlands fail first, but the motor will not last as long. Forged pistons expand/contract more than cast pistons and thus need bigger piston wall clearance; this will more quickly wear out your cylinder walls and you'll start to experience blow by, lack of compression, etc. as your engine wears out. A cast piston motor could easily last ~200k miles at stage 2+ power levels, but a forged piston motor likely will only last 60-80k miles.

330-350whp is right about the maximum you'd want for a stock bottom end; with a good tune, you can keep it reliable for years to come. Above 350whp it becomes a bit of a bottomless pit depending on your long term goals.

 

You could just do pistons to be safe, as typically those stock ringlands fail first, but the motor will not last as long. Forged pistons expand/contract more than cast pistons and thus need bigger piston wall clearance; this will more quickly wear out your cylinder walls and you'll start to experience blow by, lack of compression, etc. as your engine wears out. A cast piston motor could easily last ~200k miles at stage 2+ power levels, but a forged piston motor likely will only last 60-80k miles.

 

 

Chocoholic005 thanks for the response. From what I've read I see 350 WHP is the limit for a "stock" or "stock-ish" bottom end/short block. That is also about the limit of the stock 5MT. I figure I might as well have it tuned up to that and stop there. I agree over 350 WHP is just going to cost a lot of money for little return and usability on the street.

That being said, your cheapest alternative is just to go with a new OEM shortblock. For extra reliability I did ARP head studs, upgraded valves, springs, guides & seals, an HKS timing belt, 11mm STI oil pump and a Killer B oil pan kit, but you don't have to go the extra mile if your wallet doesn't allow.

Grab an STI RA block to start and you will have better pistons than the regular old STI SB.

 

With a good tune on e85, 350 should be super easy. Hell on 93 350 is achievable reliably.

Which OEM short block do you recommend?

 

 

The 10103AC870 is the current P/N for both a 2005-2007 Legacy GT and 2004-2006 Sti. That can be had for $2k.

 

 

I've also found the 10103AD020 P/N. That is OEM RA EJ257 for the RA2018/STi 2019-2020. It has forged crank, rods, but improved cast pistons. No idea what bearings. It can be had for $2200.

 

 

Otherwise I can get parts from someone getting rid of parts. Machined block bored to fit new Upgraded Cast pistons. King rod and main bearings, STi forged rods. I would buy a new 08-11' STi nitrided crank. Build it myself, I'm at $1550 that way.

 

 

The car had the heads redone 15k miles ago. Current original block already has ARP head studs, Killer B oil pick up, and new timing components along with Gates Kevlar timing belt. I can reuse all those parts. Like you said I would do the 11mm oil pump too.

Type RA shortblock. Just picked mine up from the dealer yesterday for $1972+ tax.

Oh, so you are doing the same build.

 

 

My local dealer wants $2227.23

 

 

FYI I was told by Rallysport Direct the EJ255 heads and RA block have slightly different port position on the cooling ports. They have to be port matched. I checked the head gasket part numbers, they are different numbers, not sure what changes, if its just cooling ports.

 

 

2005 LGT HG P/N 11044A642

2019 STi/RA HG P/N 11044AA910

The 2005 LGT really uses the early EJ257 engine; the shortblock and heads (B25) are the same as the 04-07 STI. You shouldn't have a problem matching these up. The D25 heads w/ the 07-09 EJ255 engine have a different combustion chamber size and some other minor differences that have to be considered. I'm using the standard 05 gasket kit including the head gaskets.

I wondered about that. Because one place I called said I had an EJ257 in the 2005 LGT. I was sure it was a EJ255. The new part number for the replacement block 10103AC870 fits both the 05-07' LGT and I think the 04-06' STi.

 

 

What you said the LGT getting an "early 257" make more sense now.

Where are you located wintergreen?

 

 

I got my type RA block from ebay (dealer seller from CO).

 

 

https://www.ebay.com/itm/NEW-OEM-SUBARU-WRX-STI-TYPE-RA-2-5-L-SHORT-BLOCK-EJ257-ENGINE-10103AD020/401972754187?epid=13035386808&hash=item5d9771770b:g:250AAOSwJ4hY-ieg

Wisconsin

Was yours free shipping? From my local dealer there isn't any shipping cost.

 

 

Amazon has the RA Block 10103AD020 for $1999.95 free shipping.

It was 1789+110$ shipping. tax too. But, I waited for the 10% 'ebay bucks' to pop up, which maxes out at 100$ discount.

I should also add that I am going to add the cylinder #4 cooling mod.

See a bit of info here: https://legacygt.com/forums/showthread.php/thoughts-reviews-getadomtune-cylinder-4-chamber-cooling-systemi-281855.html?t=281855

Yes I’ve seen that mod too.

.......I'm using the standard 05 gasket kit including the head gaskets.

 

Are the standard stock head gaskets multi layer steel? Are they good for 330-350 WHP?

Yes. I've built 4 of these engines and used everything form 2018 shortblocks to R/A blocks. Use OEM headgaskets and ARP headstuds. If the motor spun a bearing, get a new oil cooler as you can't clean them. Take everything apart and make sure everything is clean with no RTV chunks hiding anywhere.

I just picked up the STI RA block from Flat Irons Tuning. They've been great to work with and patient with me when I've asked questions. Especially, because I'm a noob to subaru. I searched everywhere and the best deal I got was through them. All of the parts I need for my rebuild have come from them. Plus, they have reward points, which has helped with discounts for other items.

 

https://www.flatironstuning.com/subaru-oem-2018-type-ra-shortblock

Edited March 24, 2020 by k00laid83

voice in the wilderness...ymmv

 

330hp on pump gas is an easy build, too. The 5mt is going to be the problem area. Mine was rebuilt twice before having to buy a new one when shattered 5th gear. If you are looking for a dyno queen, never mind upgrading. If you intend to DD, i'd get a 6mt. if you intend to hammer it, you might want the PPG upgrade for the 6mt.

 

Once I started making slower shifts and using 3rd/4th as primary gears, the 5mt lasted longer.

 

Intake and exhaust don't have much effect until you get closer to 400. A good up/dp help. Look for the cobb inconel up. A unicorn race part.

 

I used an outfront motorsports closed deck block with forged pistons. Startup from cold takes some time (2-4 minutes depending on temperature outside). I replaced the hg at 29k and found no wear on the cylinders. HG failed because dopehead mechanic left a rag in the cooling system.

 

The extra clearance for the forged pistons should be checked with the machine shop. If you buy a package from iag or similar, it'll be done right. The oem RA is the same way.

 

I had alot of clearance because race car. As a dd, its not the best. I run 15/40 turbo diesel oil. I buy by the gallon/pallet. OCI is 500-1500 miles. With a recent change in additives, I pour in zddp with every change to improve wear characteristics. Blackstone oil analysis has been consistent through the life of the motor.

 

The cylinder 4 cooling mod lowered temps 5-7 degrees. Seems like bling to me. Turn off your accessories and turn on the heater. When my first engine blew at the track, all the ringlands were still intact. The piston was in multiple pieces but held together by the rings. The rod however was ejected from the block in pieces.

 

Heat control in the engine bay is important especially on the backside of the engine. Don't run it hard and then park it.

 

What's your suspension and brake plan? In a 15yo car, pretty much all the suspension rubber is shot. Depending on your location, the brake lines probably need servicing too.

I can get the 10103AD020 short block for 1720 if peeps need to order it. I set some sourcing up through my business. I'm curious as to what extent the thicker crown is a benefit.

What is a inconel uppipe?

What is the ppg upgrade for a 6mt?

The cylinder 4 cooling mod lowered temps 5-7 degrees. Seems like bling to me. Turn off your accessories and turn on the heater.

 

 

I have also read that this cooling mod reduced overall coolant temp by that amount. But the most important part of this mod is to reduce cylinder 4 EGT and bring all four cylinders to more or less the same EGT level. Result should be cylinder 4 less prone to knock. Planning to add this to my engine.

What is a inconel uppipe?

What is the ppg upgrade for a 6mt?

 

I showed you this up-pipe from my collection. https://www.cobbtuning.com/cobb-history-inconel-up-pipe/

 

PPG upgrade? Its $$$$$$$$...$$$$. Obviously this link is crazy money but you get the idea: https://www.ppgearbox.com/product-page/subaru-6-speed-sequential-gear-system-2. . They also make gear sets for the 5mt and 6mt that are not sequential.

Why not just leave it stock? That's not a lot of power. Spend the money on a fuel system and pro tune.