Forged Internals vs Stock for sub 400hp in a daily

[xtea]

So I bent a rod within 15 minutes of picking up my car from having it tuned for e85 @21 psi with a vf52. I am the third or 4th owner and the guy I bought the car from was vague about oil changes, (my blackstones always came back good though...) I knew something was going to happen at some point and now I am in the inansb club.

 

Minnesota is blessed to have a large subaru crowd with lots of great guys and gals locally. I feel my mechanic is great and trust him to do well and his prices quoted are already good and fair.

 

Right now I am running a vf52 with practically all the supporting mods. I was thinking about the dom 1.5 in a year or two before the engine went boom, but I wanted to see what the vf52 could do on corn before I dropped more money on the fire in my engine bay. I didn't even really get a chance to really drive the car on e85 to know if I liked it or not.

 

Right now I am debating between going full oem or adding some forged pistons. If I knew I was going to stay with the vf52 on e85 I think I would just go oem and be done. I am fairly confident that if I wanted more power I

would stop at dom 1.5 power levels.

 

 

I like the idea of full oem for longevity, quiet, lack of blow by, and less engine wear then forged. I am worried about oem only for dom 1.5 power levels. I know though if I went dom 1.5 with oem I would tell them to go conservative on the tune. Also if the vf52 on corn is enough for me then I saved a bit of cash.

 

Forged comes with the inconvenience of warms up being far more critical. Forged pistons sometimes make less power then stock. A forged build can go wrong (though I trust the builders). A forged build might not last 200k where as oem will.

 

At the end of the day I think I'd rather go oem because it's cheaper and less fussy but I might throw a 20g or dom 1.5 on in 2-3 years also. Lots of people tell me it's all in tune and everyone else says stuff can go wrong at any time. Looking for good advice from the folks who have been at this a while.

 

Thanks!

Edited May 5, 2016 by xtea

[Rhitter]

A lot of good information in this thread (and the threads linked in it) -

 

http://legacygt.com/forums/showthread.php/finally-popped-motor-ugh-235977.html

 

Here is AZP Installs thoughts (as of 4 years ago on it)

 

http://legacygt.com/forums/showpost.php?p=4158407&postcount=8

[xtea]

I read through the thread and all it does verify I am right on the line. I am not going to track my car. It just wont happen. I think I either just want drop in pistons or full oem. Not really interested in screwing with it further then that. The wiseco point is interesting but my builder did not mention those and I have seen pictures of broken wiseco on nasioc.

[Max Capacity]

IMO, if this is your only car, do a ej257 short block.

 

If you have another car that you enjoy driving as a DD then build this with forged internals.

 

I have another car but chose to go new ej257 because I wanted a fun DD that I could drive for many years.

 

Hey this is a Subaru Legacy not a classic car with RWD that you want to drive and beat on.

 

My wagon is fun to drive, has plenty of power for a DD and is realiable. The car has great power in 2nd and 3rd gears when I want to pass someone on the street.

[xtea]

IMO, if this is your only car, do a ej257 short block.

 

If you have another car that you enjoy driving as a DD then build this with forged internals.

 

I have another car but chose to go new ej257 because I wanted a fun DD that I could drive for many years.

 

Hey this is a Subaru Legacy not a classic car with RWD that you want to drive and beat on.

 

My wagon is fun to drive, has plenty of power for a DD and is realiable. The car has great power in 2nd and 3rd gears when I want to pass someone on the street.

 

Your opinion is to stay with my current mods on a new short block and forget about it? Yeah.... For the last 2 years I have had the car I was always paranoid. I kind of like the idea of insurance for a couple of forged internals. I've asked a few places about this and people who have gone forged all suggest I do the same and the people who didn't again the same. I think your opinion is the right one but the insurance of not worrying about ringlands seems really nice especially since I might try a dom someday.

[Rhitter]

Your opinion is to stay with my current mods on a new short block and forget about it? Yeah.... For the last 2 years I have had the car I was always paranoid. I kind of like the idea of insurance for a couple of forged internals. I've asked a few places about this and people who have gone forged all suggest I do the same and the people who didn't again the same. I think your opinion is the right one but the insurance of not worrying about ringlands seems really nice especially since I might try a dom someday.

 

Builders recommend forged. Tuners say it's all in the tune.

 

Basically you just have to pick someone your trust and follow their advice. I went forged because M Sprank recommended forged.

 

From Rallispec -

http://forums.nasioc.com/forums/showpost.php?p=33477247&postcount=14

 

If I go forged again (if my engine wears out before I am ready to part with the car) I would look into the cosworth style piston. I have CP pistons which can be a little loud at start-up. Not bad (especially in CA), just a little louder than stock.

[xtea]

Im 90% sure im just going to go with the manley graded dropins. The shops tuner said the stock bearings and rods aee good to 450 if I change oils every 1500. I just want to pound on the vf52 and not worry about it.

[TheMonaLisa]

Surprised you bent a rod over breaking a piston.

 

 

Sent from my iPhone using Tapatalk

[Max Capacity]

I have to agree, "it's all in the tune". I worry more about something electrical going out, not much worry about the pistons.

 

My Tuner agreed the stock rods and bearings are good till around 450.

[BarManBean]

Surprised you bent a rod over breaking a piston.

 

 

Sent from my iPhone using Tapatalk

 

 

This. You actually bent a rod? Pretty rare failure compared to breaking a ringland or spinning a bearing.

[fahr_side]

So I bent a rod within 15 minutes of picking up my car from having it tuned for e85 @21 psi with a vf52. I am the third or 4th owner and the guy I bought the car from was vague about oil changes, (my blackstones always came back good though...) I knew something was going to happen at some point and now I am in the inansb club.

 

Minnesota is blessed to have a large subaru crowd with lots of great guys and gals locally. I feel my mechanic is great and trust him to do well and his prices quoted are already good and fair.

 

Right now I am running a vf52 with practically all the supporting mods. I was thinking about the dom 1.5 in a year or two before the engine went boom, but I wanted to see what the vf52 could do on corn before I dropped more money on the fire in my engine bay. I didn't even really get a chance to really drive the car on e85 to know if I liked it or not.

 

Right now I am debating between going full oem or adding some forged pistons. If I knew I was going to stay with the vf52 on e85 I think I would just go oem and be done. I am fairly confident that if I wanted more power I

would stop at dom 1.5 power levels.

 

 

I like the idea of full oem for longevity, quiet, lack of blow by, and less engine wear then forged. I am worried about oem only for dom 1.5 power levels. I know though if I went dom 1.5 with oem I would tell them to go conservative on the tune. Also if the vf52 on corn is enough for me then I saved a bit of cash.

 

Forged comes with the inconvenience of warms up being far more critical. Forged pistons sometimes make less power then stock. A forged build can go wrong (though I trust the builders). A forged build might not last 200k where as oem will.

 

At the end of the day I think I'd rather go oem because it's cheaper and less fussy but I might throw a 20g or dom 1.5 on in 2-3 years also. Lots of people tell me it's all in tune and everyone else says stuff can go wrong at any time. Looking for good advice from the folks who have been at this a while.

 

Thanks!

Stock head bolts are not going to hold the gaskets long at 21psi, so you need to upgrade to studs if repeating that trick.

The 1.5XTR doesn't really come alive until 18psi, so a 'conservative tune' with low boost isn't going to excite you much.

I'd do a new SB with drop-in pistons, add head studs. If you run the VF-52 for a while just ask your tuner to ramp the boost up a little slower, not spool it so hard. It's high cylinder pressure at low revs that bends rods.

Add a 1.5XTR and the stock rods will not be bent, but you may want to extend the rev range higher with a turbo that can keep up, and depending on how ambitious you are the rods may again become a limiting factor.

[TheMonaLisa]

The way I see it, bending a rod proves the tune was good and that the engine was just capable of producing too much torque. Detonation from a bad tune is what cracks pistons.

 

 

Sent from my iPhone using Tapatalk

Edited May 7, 2016 by TheMonaLisa

[shralp]

+1 for everyone's comments that it's all in the tune. Can a stock motor handle sub 400 HP goals? Absolutely. It's just that the more you push the envelope the less margin you have for error on things like your tune. The stock pistons and head studs are the only thing you'll need to worry about at these power levels. How much risk do you want to take?

 

I ended up going with a Rallispec short block (their least expensive one) with an upcharge to Cosworth 4032 alloy Pistons which are much quieter than 2618 and more "street friendly". That said the car sees mostly track time and I wasn't willing to risk stock Pistons especially with my goal to move to a Dom 1.5xtr down the road...

 

I'd probably lean towards sub 350 WHP, go stock Pistons and find a good tuner. A GOOD one. These cars at that power level are super fun and plenty fast

Edited May 7, 2016 by shralp

[Max Capacity]

+1 for everyone's comments that it's all in the tune. Can a stock motor handle sub 400 HP goals? Absolutely. It's just that the more you push the envelope the less margin you have for error on things like your tune. The stock pistons and head studs are the only thing you'll need to worry about at these power levels. How much risk do you want to take?

 

I ended up going with a Rallispec short block (their least expensive one) with an upcharge to Cosworth 4032 alloy Pistons which are much quieter than 2618 and more "street friendly". That said the car sees mostly track time and I wasn't willing to risk stock Pistons especially with my goal to move to a Dom 1.5xtr down the road...

 

I'd probably lean towards sub 350 WHP, go stock Pistons and find a good tuner. A GOOD one. These cars at that power level are super fun and plenty fast

 

 

Have to agree with the last sentence there along with the rest. At my whp the car is great fun, add another 50-60whp and the car has got to be amazingly quick.

 

There's a saying, be careful what you wish for. You need to be respectful of that kind of power on the street.

[xtea]

When I asked the builder about 4032 pistons this is what he wrote.

 

"We called them and the information we got was the 2618 material that the Manley drop in pistons are made of are actually designed to have better longevity then the older pistons and if clearances properly along with proper brake in shouldn't have any issues with engine noise or longevity. This is what all the companies were basically saying and that's what they are all using now a days. The 4032 material has been basically outdated and replaced I guess."

[Phillip J. Fry]

same predicament here.

 

if the piston rings are easily cracked as they say id rather do it once and pay a higher premium than to do it twice.

[need bb]

Go with some 4032 pistons. They are good for daily driving, but also can handle more power. You don't want to find out in a couple years that the ring cracked again and you will need to rebuild.

[fahr_side]

+1 for everyone's comments that it's all in the tune. Can a stock motor handle sub 400 HP goals? Absolutely. It's just that the more you push the envelope the less margin you have for error on things like your tune. The stock pistons and head studs are the only thing you'll need to worry about at these power levels. How much risk do you want to take?

400whp on gas or on E85? On gas that is more than the stock pistons or gaskets are going to take.

 

When I asked the builder about 4032 pistons this is what he wrote.

 

"We called them and the information we got was the 2618 material that the Manley drop in pistons are made of are actually designed to have better longevity then the older pistons and if clearances properly along with proper brake in shouldn't have any issues with engine noise or longevity. This is what all the companies were basically saying and that's what they are all using now a days. The 4032 material has been basically outdated and replaced I guess."

 

I know two guys who have broken 4032 pistons and even though I considered using them once upon a time I now start shaking my head as soon as the number in mentioned in conversation. I've been running Manley 2618 pistons at the bottom of the recommended clearance range for about 40,000km now. I use no oil between changes and the sound of piston slap is only really apparent on a cold engine on a cold day, or on a warm engine at idle and with the a/c on. Then it sounds like a diesel. Otherwise it's pretty much as quiet as stock.

 

This might sound odd, but I'm going to say building for any number between 320whp and 400whp is illogical. A stock motor is not happy above about 320whp and with forgies in you're ready for 400whp, therefore anything in between is illogical.

 

1. You can run the stock block to about 320whp and get away with some abusive driving, using normal maintenance procedures IF you're properly monitoring knock. Anything running higher boost or more aggressive timing on gas has some degree of knock. It's there, even if you don't see FLKC or IAM moving. Get the det cans out if you don't believe me. On the stock pistons you just don't get many get-out-of-jail-free passes before they're broken. Bad gas, that boost spike you can't quite fix, extra hot day your tuner didn't account for, that bad habit of sitting 5 minutes at a stop light and then racing the guy next to you while your intercooler is fully heat-soaked... it will all catch up with you sooner or later.

 

2. For anything more than about 320whp you really need to raise boost beyond the 18psi the stock head gaskets and bolts are comfortable with. It might take tens of thousands of km but beyond about 18psi the heads are going to lift and you will be pulling the motor to stop the bubbles in your coolant and tendency to overheat.

 

Now look at the cost of a new SB, the labor on stripping your old engine, freshening up the heads, putting all your ancillaries onto the new one, buying a new timing kit, water pump and so on... does anyone get through this without spending several thousand dollars?

 

3. Adding some proper head studs and appropriate multi-layer steel gaskets is by comparison a tiny extra expense you'd be dumb not to do.

 

4. Spending another few hundred bucks for the Manley forged pistons in A and B grade should be a no-brainer. Small extra expense, massive upgrade in reliability.

 

5. The supporting mods to do say 330whp and 400whp really aren't any different.

 

For me the big question is this. Is the engine coming out of the car anyway? Are the heads coming off anyway? If the answer is no, use a turbo suitable for 300~320whp, get a good tune to that kind of number, stay at or below 18psi boost and have your fun.

If the motor is coming out or apart, just drop the forged pistons in and be immediately more reliable in the 300~whp range and have the headroom to grow to 400whp or slightly more.

 

Yes there are people who get away somehow with running 400whp on the stock motor but my suspicion is that they very rarely use all of that potential.

 

Let's face it, most of us with cars doing high 300s or low 400s got here the same way. We did stage tunes on the stock turbo and got bored with the TDi-style torque spike and lack of top-end. Then we did a modest turbo upgrade in the 40~45lb kind of range, with some supporting mods for fuel or intercooling. We got greedy and turned the boost up a bit too far, ran too much timing, or we skimped on intercooling, or had a bad tank of gas, or some other event snowballed into a blown head gasket or cracked piston. (I did both at once). Everyone does this, it's in our nature to want some bang for buck.

 

What comes next is the important part. If you're willing to dial things back and live with a little less performance then by all means just drop a factory SB into the car and get on with your life. If you suspect you might get the itch to go bigger, and let's face the fact that those without these itches just stay stock, then just get the damn forgies in there and be sure and use the tougher 2618 material while you're at it.

[xtea]

Fahr_side, f&$@ yeah!

 

You da real mvp!

[Tehnation]

2618 are stronger than 4032!! it goes stock < 4032 < 2618 ..... 2618 being more so for race engine.

 

Stock rods should be able to hold up to 400whp, pistons surviving on the other hand will depend heavily on the tune, but it won't last that long. Its mainly the rod bolts that are the issue. over 400 go with better rods.

 

i'm currently rebuilding so i have been doing a lot of research and asking around. I'm going to go with je or manley 2618 pistons and eagle or manley rods.(whatever i can get a better package deal on)

 

I'm trying to rebuild my shortblock for 1800 or less vs just buying a new shortblock. From the looks of it, i can get it done for under 1800. If you pull the block and pull it apart yourself that is. If you know what your doing its cheaper to rebuild vs buying a new short block.

Edited May 8, 2016 by Tehnation

[fahr_side]

2618 are stronger than 4032!! it goes stock < 4032 < 2618 ..... 2618 being more so for race engine.

 

Stock rods should be able to hold up to 400whp, pistons surviving on the other hand will depend heavily on the tune, but it won't last that long. Its mainly the rod bolts that are the issue. over 400 go with better rods.

The rods are bent by very high torque at very low revs (as per OP), in compression. They are broken by being run at excessively high rpm, in tension. It's not that difficult to make 400whp at reasonable revs, and the bolts get the hardest time in tension. Good bolts are almost as expensive as budget rods which come with bolts... but OTOH the stock cams and heads put a severe damper on flow beyond 6k0rpm anyway, so unless you're doing head work it doesn't make that much sense to do better rods.

Edited May 8, 2016 by fahr_side

[Tehnation]

I am in this same dilemma , i want to limit at 7500-8k rpm. So thats why i am going with some cheap forged rods, around $350, the eagle and manley both come with arp rod bolts. But my goal is 400-500whp @ 8k rpm. If my goal was below 400whp @6k rpm, i wouldn't replace the rods if they were in good shape. But i think the issue is fueling!!! i'm running 93 octane....

 

hmmm he was running e85, on a vf52 and bent a rod...... when they tuned the car did they dyno it?? I don't see where he listed his actual hp! On normal gas you can get what out of a vf52 300+ whp with right mods no engine work. Doesn't e85 give u like instant 75+ hp?

 

So you had an e85 tune, no dyno? So we don't even know what actually bent that rod. Who tuned it? You need a dyno at that level, you could have actually been pushing some serious hp without knowing it!!!

[Tehnation]

15 minutes after tune the motor blew up..... that's just f'n crazy, did you question the tuner?

[Phillip J. Fry]

i like your post fahr. its really informative and fills in some gaps people, my self included, dont fully realize.

[Tehnation]

until we actually know what hp his car was putting out, its hard to say anything specific. I think the tune did it. e85 is a different animal.....

 

http://forums.nasioc.com/forums/showthread.php?t=803341

 

The fact that you can make enough torque to bend rods without shattering piston with a vf52 makes me want to go e85.....

Edited May 8, 2016 by Tehnation