Question for Doug: "But honestly the 2618 piston expands about 13% more then the 4032 at its ideal operating temp" 1. Will the piston reach "ideal operating temp" just loafing around town at 3-4 psi or will I have anoisy motor that burns oil when heading to the Dekalb Farmer's Market? This is a grocery getter, not a track whore... 2. I completely understand how you like the CPs- you found a product that has given you consistent and reliable results and it makes sense to stick with what works rather than throwing another variable into the mix Question for slowwrx: I guess I do not understand what the comment about drop-in pistons to a factory shortblock... my understanding is that very few machine shops could have a bore dimensionally as good as a factory block not to mention a cross hatch that should be picture perfect... If I start with a brand new block and the rings are properly filed to the piston manufacturers specs why would this NOT result in a long running block at 350-400WHP? Are the factory main bearing clearances no good? What am I missing not understanding? So.... do I just stick with stock STI cast pistons? It seems there is no love for the Mahle's and I am unwilling to accept the baggage that comes with a 2618 piston. Anybody have some Beryllium or magnesium pistons? How come nobody makes a ceramic piston? You'd think that could be a winner...
I am by no means the expert here Mark, but I do know a thing or three. Doug drives his car every day from work and back...4miles with a quick 1-2 min warm up in the morning, and normal driving. (I am using his motor because thats the one we have maintained, we have lots of happy customers running the same engine.) His car uses LESS than a half a quart per 3k like I told you, unless he tracks it, it isn't "loud" although it does quite down a little after its warmed up. As far as the factory short block with drop in pistons...well you already know my opinion on that as well. If you want it to be even quieter then ceramic coat the pistons before slapping them in.
If this is primarily for your wife to drive I think you are making a mistake dropping in forged slugs. Don't expect a very long life out of forged pistons.....60-80K is the norm but many never make it past 20k
Hard to really say as I would guess 90% of those that go to forged pistons ALSO go big hp at or near the same time. How long might they last at factory levels? Look at the EJ207. Forged factory motor.
Have you even researched the EJ207? The clearances on those are way tighter than the typical forged slug builds. IIRC correctly they were very close to stock USDM clearances. Which is why many of the higher boost EJ207 end up seizing.
Cicio you have a good point on the coating part, of course you would want TPFE coating for the skirts and ceramic for the piston top. With that being said, if you take a piston and send it off for coating you will have to take into consideration of the piston to wall clearance and hone the block accordingly for the desired clearance. There's a little more than just dropping a piston in and calling it a day if anyone decides to go that route.
I'm with Doug I like CPs as well. Improper Piston to Wall or Ring Gaps cause burning oil. A properly setup motor will now burn oil with either alloy piston. As for what I was saying about Drop Ins. I think if you are going to have the motor far enough apart to put pistons in it, it doesn't take much more to split the case and have the blocks bored and honed. Factory tolerances are anything but ideal and the bores vary wildly. Ball Engines uses a torque plate to bore and hone all of their Subaru blocks, as far as I know they are the only ones in GA with one(could be wrong). Honestly at 400whp I wouldn't even put pistons in it, theres not really any reason to.
Your point being? My point was that at oem levels forged can be quite reliable as well, but when you get into big boost, stuff breaks. You are quite correct. We bought them ourselves and they are used on every engine that goes to the machine shop.
Update In for a penny, in for a pound... Well I have a new STI shortblock headed my way. I will be keeping stock STI pistons, but rings will be filed to assure proper gaps. If gaps are wrong on the piston to block- I'll send the damn block back! Other areas of improvement: Killer B oil pickup STI oil pump ARP head studs Factory headgasket set all new OEM timing belt/idlers/water pump (the whole shebang OUCH $$$!) AVO throttle body intercooler hose and T-bolts(the stock one SUCKS!) 2009 STI top feed fuel rails ID-1000 injectors w/ PNP harnesses Topfeed TGV Deletes (nicely ported and polished by Breel bought from Mike S- LOL) Heads will be taken apart and cleaned up. This will effectively be an "AS NEW" motor with better oiling system, way better fuel system ( I already have an AVO fuel pump). So one last dumb question... due to injector change, Doug will be doing my tuning... I have a hybrid VF40/18G turbo that is 3 years old. I have reservations about putting this 3 year old turbo on a brand new motor and possibly having it come apart... 1. Do I drop another $700-$1000 on a new turbo for peace of mind? 2. Do I get an EVO3 16G or a 68 HTA (both are offerend in VF40 housing by BNR turbo) If anyone wants to read up on LGT and 2008WRX fitment how about a 144 page thread (just the first post is the options) http://legacygt.com/forums/showthread.php/bolt-up-turbocharger-upgrade-119177.html
I would NOT do the ARP headstuds......unless only Topspeed is installing them. Oh if there is no to minimal shaftplay I would use the turbo you have. It's not gonna kill your motor. If anything it'll smoke/leak which is an easy fix.
ARP studs are fine, just know you're going to have to retorque them once the motor is broken in. You honestly don't need them if you're just running stock boost levels, though. As for the turbo, you can probably have it rebuilt for a couple hundred if it's that big of a concern. It shouldn't effect yuor motor even if it's bad, you'll just lose oil and power. Congrats on the decision...I know how expensive these silly things can get
Hence why I said unless Topspeed is installing them. And stock headstuds are good for 30 psi up to 600hp too.
Doug walked me through the proper torque procedure when I built my first engine with arps and never had an issue or had to Re-torque. They are a bit overkill tho unless your doing a big build.
I hear everybody on the ARPs. I got them for dirt cheap so it was a no brainer. I already bookmarked the Doug thread on using heatguns to get proper torque with ARP fasteners. I think we will be OK. P.S. Well since I am using ARP fasteners is it OK to push 35 psi with a 3 year old 18G? Would that be outside of the efficiency range of an 18G? How far outside? Could I use the air coming out of it to burn up some leaves in my driveway?
Honestly...I'm just too lazy to look for it, but - do you have the compressor map? Find it and post it, they're not that hard to read. My guess is, that's way outside the efficiency range, but until I see a map I can't be for sure. From what I've seen, the BW turbos work really well at higher boost pressures
24-26 psi is about all the 18g will do without turning into a heat gun and that's with methanol injection.
Trying to push 35psi on a factory location turbo is going to make that motor go boom again bro....regardless if its efficient or not (which it wouldn't be at all) Your drive pressures would be through the roof!
Wow... Now I understand why some people on this board act like smart asses all the time. It's kind of fun. More people thought I was being serious than thought I was fucking with everybody. LOL. I need this motor to go another 100K. That's why I'm not getting forged pistons. And No I will not be running 35 psi. That would probably be something absurd like 50% efficiency (or less). I've read Corky Bell's book so I'm not a complete noob, but I do play one on this forum. I warned Alex about letting me become a supporting member. Now I feel entitled to waste your time and bandwidth. Entitlement... there's a concept that has served Americans well... he-he.. as in I feel entitled to have 300WHP. At least I know I'm a hypocrite... But SERIOUSLY thanks for everybody's inputs... All you can do is read up and be realistic about what you want. THANKS TO EVERYBODY FOR THE SUPPORT IN HELPING ME DECIDE WHAT TO DO... even if I am not doing specifically what YOU think I should do- LOL.
Ha I knew you were joking and played along. You'd be surprised how many of us do that How's that beautiful wagon of yours doing though? Still running well?
Well... my beat ass 2002 WRX Wagon daily driver just went over 175K. Never burns oil and I drive the it every day to work. Pretty stock just an Evo 2 exhaust and JDM take-off suspension with Group N mounts. Stock HP, no accessport. Stock and the car seems to be happy that way. 2005 Legacy GT Wagon... still driving with no compression, but just under 4K RPM no boost- just for taking the family to the park. New shortblock goes in this weekend... right Breel? Breel? HelLLOOOOO>>>> Has anyone seen Breel? just kidding. I have infinite faith in Brian to do this right. Or my wife will be killing both of us.
ARP Headstuds are fine. You just have to torque them down correctly the first time. I did not have to retorque mine after the motor broke in and neither did Mike. I know who is putting your stuff together and you should be fine
Kind of like that Harry S Truman quote about reading newspapers with opposing views, after reading both sides just make up your own conclusions.
Have you ever noticed how bad news is almost as exciting as good news??? So an update... I ordered all my parts including a new factory EJ25 shortblock. Motor and parts were supposed to deliver last Friday. The timing kit head bolts, gaskets, and some other stuff delivered on time Friday... hmm NO shortblock. Delivery date pushes out to Monday... lost the weekend. FIGURES.... Monday comes and goes. Finally out for delivery this morning. UPS dropped the son-of-a-bitch. ruined a brand new block. And I am behind the 8 ball on time now, of course. Already had to get a rental car. I will however pat myself on the back for being smart enough to get a one week rate as I just had a feeling this was going to keep going smoothly... So... all the forged piston fans will be so happy... rebuilding my block with Eagle Rods and 100mm Wossner pistons (check the ringlands on these babies!) http://www.maperformance.com/wossner-pistons-subaru-ej25-wossner-ej25.html
Ugh 8.0:1 compression? Off boost is gonna suffer but at the same time you can boost more if you have the turbo to do it.
He could but I wouldn't play with that.....his luck is bad enough. :rofl: sorry I had to as it sounds very familiar to what I experienced
going to disguise it as a halon fire extinguisher setup in the spare tire well... with carpet and neon back lights by "Ghost"
How about dual fake halon extinguishers with one actually as nitrous and the other as a surge tank. But since I have a wagon there is no trunk to "protect" my precious cargo. Since I have no trunk maybe I could mount the surge tank under the baby's carseat. I don't need that part of the floorboard anyway. That might be a better utilization of space. And it would still look like a fire suppression system. Woohoo. I win.
Actually we were thinking of mounting the surge tank in the driver seat right under my ballz since I don't plan on having anymore kids.
Innovative solution! Since I am rebuilding my motor I can not afford to have another child. I will seriously have to consider this...