fahr_side

Sounds pretty normal. Piston slap is worse with lower ECT, rpm and higher load. Worst will be cold and with loads like the a/c on or the car in D (on autos). As revs come up above 1k0rpm it should go away. If you run the car hard for 10m or so the sound should also go away. You get used to the clip-clop of horseshoes while idling, or turn the radio up to cover it. Sent from a device using some software.

Lots of later model cars have no gauge, just a low and high coolant temp warning light. 2012 LGT for example. When does the blue light go off? I don't have a clue, it's not in the ECU code. Boxkita is quite right in that the oil wants to be up to temp before putting much load on the engine. That's the best parameter there is for how much the pistons have expanded to take up the PTW clearance. I live on a mountain so I tend to just let it warm up enough that the idle drops below 1k0rpm and then basically roll down the hill. Coming home I'll let it idle until the gauge is in the middle but I do not romp on it until several minutes after that. As to the power level for stock pistons... Any amount of knock is going to kill them. Those running on piss gas are lucky to break 300whp safely. Any time spent above 18psi is pushing the stock head bolts. This becomes even more of an issue as the mileage creeps up. How are you going to get to 400whp if you stay at or under 18psi? Most of the expense in swapping to forgies is pulling and splitting the motor, plus all the parts you'd be dumb not to replace while the motor is out. Therefore it's dumb to put stock pistons back in or reuse stock head bolts unless you're 100% sure you're happy at or below about 300whp. In summary, below 300whp you should be fine with the stock SB as long as you're not knocking and don't get greedy with the boost. Above 400whp we can all agree you need the forgies and head studs. Anything between those numbers you are either over-building a little for safety or skimping and hoping for the best. If you're sure 335.66whp* is the perfect build for you and you'll never get greedy then maybe you are that one special snowflake for whom the 4032 forged piston was developed. * or some other arbitrary number between 300 and 400. Sent from a device using some software.

Hardware is Lego (albeit expensive Lego). It's the CANbus electronics that will make the most trouble. Sent from a device using some software.

Again, CANbus issues. You will need to research which parts are different between CVT and 6MT platforms but you can expect most or even all of the following have to be swapped to avoid limp mode: Body Integrated Unit ABS computer Instrument cluster HVAC cluster Look up the price of those parts and cost of getting them from Canada before getting too excited. Of course you'd also have to wire the car as a manual and succeed in flashing a manual ROM to the ECU, which isn't always possible. Look at the price of an ECU as well, just in case. Then there's the pedal box, shifter mech, trim parts, clutch cylinders etc. Now note that swapping isn't easily reversible and greatly reduces the used value of the car unless you run into someone with preferences as esoteric as your own. I've done loads of swaps on earlier cars and even pre-CANbus stuff will surprise you with how much needs changing. Throw in modern networked electronics and it gets really expensive, especially when the parts are not just chilling in a local scrapyard. Sent from a device using some software.

If you end up with 3.6 power, you will end up with worse than 3.6 economy. A high compression engine on boost must run quite rich to avoid knock for one thing. Another issue is that since the supercharger is running at all times, even in cruise, you have a parasitic loss of power you have to pay for with fuel. I have yet to buy any kind of 'kit' that was 100% complete and just bolted up as per the instructions. Some extra work is always required. Perhaps Raptor is better than this and has thought of everything. Perhaps not. Mmm. I know people have broken the stronger CVT fitted to FXT and WRX models simply by spooling the turbo too hard and at too low rpm. Aren't superchargers celebrated for that ability to produce high torque at very low rpm? Again, if you're looking to approach or beat the 3.6R output then Subaru's fitting the beefier trans to that model might be a hint the small one won't survive. I'd wait for someone else to test your theories out. I've seen a few XV models with the AVO turbo kit do okay but as you mention those are FB20 units not FB25. The beefier CVT will very likely not play well or at all with the existing TCU in your car, and the TCU from the 3.6R etc. will have a different CANbus address than yours. Plugging it in (assuming the connectors are the same) will result in a CANbus error that will limit you to 50% throttle angle, which makes your blower kit kind of useless. It might even refuse to engage any drive range. More research is advised.

Let the car warm up properly before moving it, use appropriate oil and change it often. I'm at 40,000km on the Manleys and have only just begun to use enough oil to start to think about maybe installing the AOS I've had laying around for a year. Remember Subaru themselves were installing forged pistons in EJ20K and G motors their whole production runs and in the EJ207 until a few years ago. Sent from a device using some software.

Metric... 0.08mm is about 0.0031"

The 1.5XTR on a 2.5 spools like an 18G. Every non-caged Subaru I've been in that had over about 450whp felt as sketchy as ****... like 'I was lucky the engine didn't get it's way and tear the car apart' kind of sketchy. Not just pay for machine work but also 1) give up the very good factory hone on the cylinders in exchange for whatever your shop can pull off (and we know how that can vary), 2) break apart the bottom end for really no good reason. I run mine at 0.08mm PTW clearance. It's not recommended to run them tighter, even though many do get away with it. There are consumers that want the reliability of forgies, or just the bragging rights. They don't want extra noise or oil consumption or anything else and they insist the builder uses a tighter PTW clearance than the piston manufacturer recommends. All is well until the first time they go to the track or even do a longer or harder than usual run up a pass road.

How long have you been running this? I used to be a fan of the Cossie pistons but a few users found the (very thin) rings wore out prematurely. In retrospect it does seem odd to offer the street-friendly 4032 piston with very race-oriented narrow ring kits. Sent from a device using some software.

A head lifting isn't going to lead to the rod bending. Water doesn't seep into the cylinder while the engine is stopped and while running not enough gets in to hydrolock the cylinder. But yes, the Manley drop-ins plus studs is how I would approach this. Don't worry. Almost no-one pulls the engine a second time to torque those studs again. ...and the '08~ STi motor has a lower static compression ratio than regular LGT/WRX/FXT stuff and lower dynamic compression due to the D-AVCS layout.

I think I've made this pretty clear by now. IF you've bent a rod, "just ask your tuner to ramp the boost up a little slower, not spool it so hard". I thought you'd have a VF-52 surging hard during spool before you bent a rod but who knows until it happens?

I had to go to 99.75mm but the clearance tolerance range is the same for all diameters. Well, let's see how it looks when it's opened up. You usually bend a rod from too much cylinder pressure at low revs, where overrevving leads to broken rods. A bent rod will usually result in one cylinder not firing at all, massive vibration, but not always strange noises. Yes, that's safer in terms of avoiding bent rods.

Manley's PTW specs work well, I just targeted the tight end of their suggested range. Sent from a device using some software.

No I meant piston to wall. On the bearings I went to the upper limit in the FSM.

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.

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

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.

None of the aftermarket STi cams I've seen have those drive slots, since the STi doesn't need them. IIRC S2baru had to slot his Stage 1 passenger side cam as it did not come with a slot. Now, if Mike had slotted a stock STi cam to use in the W25 heads, that was indeed a waste of time. We measured the lift on the BR9 intake cam vs. the GRB item and it came out the same. While we have no equipment to measure duration the cam profiles look identical side by side.

Note that you still cannot easily run a larger exhaust housing, certainly there is nothing out there fits the stock header. So, while the exhaust cams will certainly give you a bump in output the flow balance between hot and cold side flow is better on the 18G than on the 20G. Ask anyone who's run a TD05-20G on an oldskool 2.5 WRX, EGBP and EGT can really get out of hand. Those guys barely get away with it using 8cm2 housings and unfortunately the housing on the VF-54 is only 7.5cm2. Note the turbine efficiency is also going to be off a little since the housings are custom machined to take the bigger (than stock) TD05H wheel. That's never going to work quite as well as a housing designed specifically for the turbine.

And if there needs to be a hole, the hot exhaust gas will cut one anyway. Sent from a device using some software.

Nice noise btw. Until it gets old Sent from a device using some software.

You really want to run a pan, as that is key to efficiency in both radiator and intercooler.

Curious... do you have the undertray installed?

NZ = JDM. It should be a TD04HLA-19T. Sent from a device using some software.

Better warn admin his account has been hacked.