Sarg

iTrader: (6)

It is not uncommon in the Subaru world to make 400 awhp on stock cast piston and rod long blocks with only 2.5 liters through an awd transmission. Double the cylinders and 800 should not be terribly tough. I think it probably comes down to the tune.

Travbabble

iTrader: (1)

This isn't the Subaru world. You cannot compare in any way the two. Different manufacturing standards, techniques, materials etc make them completely un-comparable. The only comparable things are that they have four wheels, and are propelled by tiny explosions.

9sectruck

iTrader: (9)

LOL. please dont start a war in my thread.... I have let the pass go at this time

Im really starting to lean towards the thick oil at this point,
just thinking out loud is there a possibility that the thick oil is building up behind the bearings and actually pushing the bearing out of its cradle and forcing the bearing up into the crank????
anybody's opinion....

Sarg

iTrader: (6)

Cast pistons, rods, cranks. Just saying the same explosions are happening in both motors and applying their force to pistons, rods, cranks and valves made of the same materials and manufacturing processes. Motors are motors!

As for the weight of the oil, I choose a 10w40. I would not personally go thicker unless your tolerances are very loose and necessitate it. I run rotella 10w40 in my junk and it seems to work well.

M2W-GTO

You mean the same way you came into my thread (which I created searching for advice) claiming the same exact thing to me? Saying you were glad the Tuner blew my motor up? Well sir, this is the epitome of karma at work. Not looking to start a war, if I was I would have all my friends create accounts to come make blatant lies up in here, the same way you did with mine. Good luck with it, hope you can get it all lined out, your shop's customers look to this for reassurance, I'm sure.

M2W-GTO

That's kind of like saying soda cans and engine blocks have the same strength standards, in a sense. Metal is metal! Obviously false.

Sarg

iTrader: (6)

So one set of cast hypereutectic (sp) pistons is better than the other? If so, which one?

M2W-GTO

I mean, I feel it's safe to assume LS3 piston's are stronger than that of the ls1 piston's, wouldn't you agree? Thus, I also feel ls1 piston's are stronger than a Subaru's stock piston. Just my opinion, though.

Travbabble

iTrader: (1)

I can't tell if you are trolling or not. It's hard for me to believe that someone could seriously even compare a 4 cylinder boxer engine to a pushrod v8 in the sense that if you can do X on one then you should be able to do Y on another.

Slowhawk

iTrader: (12)

I'll say the oil is too thick. We run VR40 in alot of our boosted cars with no issue's. Street cars get mobile 1 0w-40 with no issue's the last 10 years.

boostit5.3

iTrader: (3)

im using 10w30 penzoil synthetic on a 5.3 with around 140k.. i had something similar in my oil when i did the first oil change (i did a cam swap when i put the motor in) and the assembly lube i used caused my oil to look all glittery. i also had some metal on the magnetic drain plug/in the filter but all is well... i've been daily driving it and i ran a 11.8 last weekend on low bottle pressure lol

Sarg

iTrader: (6)

Eh yes and no. Having held both in my hands and taken both out of their respective motors, both have good and bad points. Both ARE cast pistons. The Subaru pistons are designed specifically for boost, but do have thin top ringlands just like the LS motor pistons I have seen in the 5.3s. Personally neither are the BEST choice for forced induction, but if you are careful with the tune you can make them both live. There are guys who have taken the 2.5 liter OEM short block with stock pistons from Subaru and had over 500 AWHP (read 650ish at the crank) and ran it for 20,000 miles of road racing. That may not seem like many miles, but they have to be doing something right when others are blowing their junk up at 350 hp.


Not at all. I was quite serious when saying if you can have a 4 banger making 125 hp/cylinder with cast pistons, rods and crank, it should be doable with a 8 cylinder LS motor (with its larger displacement per cylinder) as well.

I have an old customer who currently has 214,000 miles on his OEM stock STI long block Subaru and is making 400 awhp. For those that no nothing about the Subarus, they have about a 20% drivetrain loss due to the all wheel drive system. Chances are he is making around 500 at the crank if not a tad more. This is on a stock block with razor thin sleeves (similar to the LS1 sleeves), stock CAST pistons, stock cast rods, stock cast crank, stock as cast heads, stock valves, stock cam, stock everything except the injectors, intercooler, turbo and fuel pump.

If that little motor is able to do it with the limitations that it has from the factory (exhaust ports are horrible and have a nasty dog leg) then I don't see why a LS based motor could not also make 100+ hp per cylinder with their design. People are proving it because they are doing it. If anything I would say the Subaru block is a worse design and is harder to make serious hp on a stock block than the LS blocks. The head design is not even close to an ideal situation.

The original topic was how are people getting these stock blocks to survive. My answer is that it is in the tune. There are a number of people breaking pistons and tearing up bearings while others are able to continue to make these things survive. I say that a good bit of that is in the tune. Look at Skinnies. He has taken his straight from the junkyard motor over 800 whp and beat the crap out of it and it was a stock short block, stock heads motor. My thought is that the tune has an awful lot to do with how well the motor survives.