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#16
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Re: Twin turbo TD04-13T project: Journey to 300+whp
I haven't heard this before on any eg33 build threads. Is it due to a weakness of the piston/rings, or that they need to be gaped so they don't seize in the cylinder?
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#17
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Re: Twin turbo TD04-13T project: Journey to 300+whp
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The ring lands blow apart from heat/detonation and in almost all cases, it is cyl #5 that goes (first). If you're trying to reach 300whp, take into account a good running, lower mileage SVX with m/t dynos out around 175hp. So you're essentially needing/wanting to nearly double the hp numbers. That means you need to double the air the engine gets. So basically, you're needing upwards of 15psi to achieve this. 1 atm=14.7psi aka, no boost-n/a engine. So doubling it would get you 350whp. However, then you have to account for losses due to the higher intake temperatures. Get the idea??? Again, this is VERY BASIC and in no way truly accurate, however, it's the absolute easiest and quickest way to estimate hp if you're keeping everything else the same and adding a turbo and appropriate mods. With that said, at 15 psi, even intercooled on pump gas, you'll be blowing pistons apart. E85 and you should be okay as long as you're not doing endurance racing/offroad racing. But again, it's absolutely pointless to do rods on this engine. If you're going to upgrade anything internal, it needs to be the pistons first. Anything else, is simply a waste. You're also going with an auto trans, so your stock whp will be even lower than that 175hp thanks to the wonderful losses of the torque converter. |
#18
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Re: Twin turbo TD04-13T project: Journey to 300+whp
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I've searched for quite a while, and have spent hours upon hours reading build threads and speculation about the eg33 in both NA form and forced induction form. Not one thread I've read mentions the pistons being weak nor needing 'upgraded before the rods'. I'm not saying you're wrong, simply that I've never seen this being said before. Bazza is an excellent case. He's running stock pistons with trimmed rings, 10psi on a GT35R pushing over 350whp and he upgraded his rods. Last edited by BackWoodsBob; 08-10-2013 at 04:17 PM. |
#19
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Re: Twin turbo TD04-13T project: Journey to 300+whp
http://www.subaru-svx.net/forum/show...ng+land&page=4
Most significantly, take a look at post #44 which explains that YT and OT both had failures on cyl 5. I also have an SVX that I believe has a failure on 5 that is n/a with 102k miles when I purchased it. It has piston slap bad enough that I have had 3 separate subaru people immediately think it was rod knock. http://www.subaru-svx.net/forum/show...9&postcount=44 Also, I believe Phil is the only one who has pushed any true amounts of boost through an otherwise stock engine that hasn't blown up. Almost all others have run low boost and got out of the SVX as it aged before pushing any further. Most others have gone on with building the engine up first before anything else. This is why most of the projects have gone on a few years. Bazza has a big turbo (big turbo means boost/heat comes on later when it can flow more air out) also has VERY aggressive cams with different valve/spring setup allowing the air to move. His car is a track car, he wants/needs his hp up high. For what you are wanting, you need to compare apples to apples. I believe you are wanting a good all around engine with plenty of torque, or I may be getting you confused for someone else? Anyway, besides anything else, The pistons are absolutely the weak point on this engine. Plain and simple. I come off as an ass in almost all cases, but realize, what good is it if you go through all the work only to blow pistons apart? The rods are already forged, the pistons are not on this engine. Last edited by 1986nate; 08-10-2013 at 04:51 PM. |
#20
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Re: Twin turbo TD04-13T project: Journey to 300+whp
I agree with comparing apples to apples.
Tom/ was using a twin screw SC without cooling his charge. He was easily blowing 130+f air into the engine. I will be the first to admit I don't know everything, or much about boosting cars. However, one thing that I do know is heat is bad, not cooling your intake charge is paramount to suicide. I do appreciate you being an ass, I didn't make this thread to hide and ignore others criticism and advice . From my understanding the rods are regular cast rods used in the ej221,(e?) and the pistons are cast. It seems most of these threads bring up detonation being the issue with busting pistons and killing the engines. Unless I've missed something? Last edited by BackWoodsBob; 08-10-2013 at 05:12 PM. |
#21
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Re: Twin turbo TD04-13T project: Journey to 300+whp
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Interesting. I'll keep this in mind and inspect my spare blocks pistons once I split it. |
#22
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Re: Twin turbo TD04-13T project: Journey to 300+whp
I know they are different motors, but I have lost 1 EJ205 and 1 EJ257 personally to blowing ringlands apart. Both were OEM turbo motors running about 18 PSI on a mild turbo with very very good tuning. They both went at about 100K miles. I also lost 1 EJ205 to a burnt valve, thankfully with the hydraulic lifters in the SVX we don't have to worry about the lash tightening up keeping the valve from seating completely.
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#23
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Re: Twin turbo TD04-13T project: Journey to 300+whp
Ringland failures in the EG33 has been, at least from my accounts, totally related to detonation. This due to poor tuning. Even totally stock engines have shown me det burns on the outer edges of the pistons likely due to bad gas. The pistons can take 300 whp, tuning is the issue.
In all honesty, if you are splitting the bolck, why would you use stock pistons?? They are a restriction to how much power you can make due to the compression. Get a set of custom low compression pistons made, don't sidestep your build with shaving stock pistons. Pay attention to your bottom end. Slightly larger oil clearances with a high volume oil pump and some good bearings is a start. H-beam rods and ACL race bearings is a good finish. Running a 40weight oil is also a good idea to help maintain a better oil pressure and keeping the bottom end wet. ringlands break from detonation before they will from power Tom Last edited by TomsSVX; 08-11-2013 at 06:56 AM. |
#24
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Re: Twin turbo TD04-13T project: Journey to 300+whp
You're correct. At least until I finish building my spare engine . Then all bets will be off.
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#25
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Re: Twin turbo TD04-13T project: Journey to 300+whp
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Almost every 'built to withstand xxxhp' engine I've seen needs to be rebuilt frequently. I figure, as long as everything is healthy in the engine, keep it oem spec and make it as boost friendly as possible in stock-form with 100% oe components(or as near to factory as my plans allow). If I can find them I'll get OE bearings and freshen things up and spec out the crank while I'm there. Last edited by BackWoodsBob; 08-11-2013 at 08:54 AM. |
#26
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Re: Twin turbo TD04-13T project: Journey to 300+whp
I'm curious if anyone who's boosted a stock eg33 without splitting it/removing the heads took the time to steam the cylinders of all carbon? When I did HG's on my other block the pistons had a good layer of carbon built up. I removed it all, but, how many others took the time to do a non-invasive clean their combustion chambers before applying a SC or Turbo?
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#27
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Re: Twin turbo TD04-13T project: Journey to 300+whp
If 1100 is gonna stall the build.... let it imho. Dont run higher boost until its actually ready.
Tom |
#28
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Re: Twin turbo TD04-13T project: Journey to 300+whp
Fair enough, and sound advice.
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#29
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Re: Twin turbo TD04-13T project: Journey to 300+whp
Stock pistons are fine to a lot of power and cylinder pressures as per any other Subaru engine. Issue is the tune, not many people actually understand this and never will. My current engine in the racecar is a stock STI engine running close to 30 psi... good safe tune!! And the old EG33 saw up to 15-16 psi on the dyno and ran around a racetrack for a long time at 7-10 psi. Given the cost of forged pistons I probably wouldn't touch the stock ones unless aiming for above 500 bhp. The power above is nothing for these pistons.
Get a good safe tune and it will run a lot of boost for a long time. I couldn't break my turbo EG33 at the track in the harshest of conditions (major oil surge and 32-35'C). Get the tune wrong and it will last 5 seconds!! Last edited by bazza; 08-11-2013 at 07:56 PM. |
#30
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Re: Twin turbo TD04-13T project: Journey to 300+whp
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Cams were stock for most of the time the engine spent on the track. Stock cam and spring setup for most of it, upgraded the cams at the very end. Stock engine was making 1000Nm torque at 3750 rpm, due to stock cams engine was out of puff at 5500 rpm. EG33 was chosen due to the torque, not peak power. New engine is simply for peak power... it's a 2L. At least get your facts straight before making comparisons Last edited by bazza; 08-11-2013 at 08:03 PM. |
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