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 Post subject: Re: Sanity Check - Help me Brains Trust!
PostPosted: Fri Aug 31, 2018 10:26 am 
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I Say: There's no 'i' in Team, but there is in Winner!
Vehicle: MY10 XT

Posts: 1784
Location: Mealbun Orstraya
I do love the American dyno figures and not to mention the pointless chest beating that goes between themselves.
Best post I saw “dude, you should be making more than 350hp with the VF52! Mine is making 400hp!”
Then insert tirade of which dyno manufactures is better..
:lol:


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 Post subject: Re: Sanity Check - Help me Brains Trust!
PostPosted: Fri Aug 31, 2018 11:15 am 
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Vehicle: MY10 XT

Posts: 48
Location: Melbs
A lot of the setup for the build was done with the dom 2.5 in mind (compression, fuel and injectors). I really want to keep the stock location for the turbo (less suss looking if the popo lift the bonnet) and pending some results from my tuner on one of the larger stock location gt pumps turbo looks to be the way I will go. Honestly I'm not shooting for a 300kW car. Something in the mid 200s that feels well connected to the road and is reliably tuned for that power day in day out is what I really want. Long term plans are to build a properly fast car on a more sensible platform and keep the foz the way it is (drivable and quick) as it suits my lifestyle.

I'm learning a bunch about cars as this is the first car I have modded. and hope to do a lot more of the work on the next project.


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 Post subject: Re: Sanity Check - Help me Brains Trust!
PostPosted: Fri Aug 31, 2018 12:54 pm 
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I Say: There's no 'i' in Team, but there is in Winner!
Vehicle: MY10 XT

Posts: 1784
Location: Mealbun Orstraya
Best thing is to find someone with a similar powered Subaru, ask them a bunch of questions and then see if you can go for a drive with them. That way you really know what you are getting into :ok:


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 Post subject: Re: Sanity Check - Help me Brains Trust!
PostPosted: Thu Sep 06, 2018 8:43 am 
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Vehicle: MY11 S-Edition - SWP

Posts: 1118
Location: Sydney
Bram wrote:
jonp wrote:
Will the bottom end quiet down over time?


No.

The noise is a because a little bit loose piston to bore clearance. The reason you loosen the piston to wall is with forged alloy pistons, they expand at a faster rate than the block. So when hot that clearance reduces. But when the engine is cold, it willl rattle like a tracktor. If you dont drive it hard enough to keep heat in there, it will still rattle like a tracktor. No amount of KMs will reduce the piston clearance. Infact, if anything, it will only increase with use.

Some engine machineists will take a forged pistons recommend PtB clearance, and then increase it more for an evenn more rattly engine, because either lazy machining, or stuck in the mindset that the piston will grow. Obviosly piston manucfactures already account for the heat expansion with thier recommoneded clearances. And they leave a little wiggle room, because having a loose fit is a million times more desireable than having a tight fit nip up in the bore and destroy an engine. When the engine machinesist does the same thing, and set the clearance a little looser than the piston manufactures recommended, (because again a little loose is more desireable than too tight), you end up with a motor that is definitely too loose. And it will be a noisy engine.

The other common cause of engine noise on subaru builds is the excessive valve lash. The lash is set with individually sized and purchased lifters/buckets. And these lifters arent cheap. (More than $50 each in Aus, and you may need 16, plus subaru australia literally carry 0 stock, so order in from overseas, and associated delays with sourcing them, not practical for a shop where time is money) so often they will be re-used and swapped about with whatever they happen to have lying around. (The mix n match approach) Every subaru builder will have a big box of used lifters for this exact reason, but i can garantee, none of them will have every size in his collection. As its not practical.

And ontop of that, setting the lash correctly is immensely labour intensive, like to do it properly, you gonna take the best part of a full day, no joke. So quite often, its not practical to spend the time getting it exact, because the customer is gonna complain when he gets a $1-1.5k bill just to set his valve lash. And then there is joe blow heads who supposedly do the entire job for half that. Well guess what, its not gonna be exact. And then there will be rattly lifters too.
Thanks for the explanation Bram.

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2011 S-Edition SWP


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 Post subject: Re: Sanity Check - Help me Brains Trust!
PostPosted: Thu Sep 06, 2018 11:28 am 
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Vehicle: MY10 XT

Posts: 48
Location: Melbs
Just because it does my head in not seeing dyno sheets with this sort of stuff here are the sheets from the latest tune. One showing boost (and it's diminishing number) and one showing torque.

The green line is the car with VF46, boost controller, TBE running a pretty consistent 17psi.

Red is the same turbo ID1050x injectors, DW300c fuel pump, split rails, e85 and all the built bits. As you can see runs at 20 but drops to 15psi as the smaller turbo runs out of puff.

Current status on the build has shifted to getting suspension sorted (Anyone have a preference between the MCA purples and the BC BR coiovers?) and dealing with a little boost cut that keeps popping in at the worst times.


Attachments:
boost.jpg
boost.jpg [ 262.14 KiB | Viewed 34 times ]
torque.jpg
torque.jpg [ 260.03 KiB | Viewed 31 times ]
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 Post subject: Re: Sanity Check - Help me Brains Trust!
PostPosted: Thu Sep 06, 2018 11:51 am 
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Vehicle: MY08 XT (SH)

Posts: 1286
Location: Brisbane
About a 20% increase in power across a near-identical-shaped power curve is the same as what I observed switching to E85 with a VF46.

Obviously the different tuners, tune style, dynos, parts, etc makes it hard to make a really close comparison.

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My build thread: viewtopic.php?f=12&t=54775


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