Leighos

I also confirm those dimensions. Just for interest sake, here is a really good example of a TD05H-16G \'small\' compressor housing rework that I had done. The cast 90° inlet was removed, OD turned down and face of housing milled flat - then inlet was reinserted, welded and ID turned to produce this near perfect join. Absolutely smooth and seamless!

I wonder why Subaru choose the unequal length for the turbo\'s over this design?

It does appear to be slightly raised which is what concerns me, and just in that area of the housing too - the rest is quite smooth. The turbine wheel itself does have some tip erosion, but the area where that blades are radiused (where the corresponding marks are) don\'t appear damaged. I\'m just concerned that if someone has welded this up in the past for whatever reason, maybe to fill excessive corrosion, that there may be a cracking issue from dissimilar metals - I\'ve tried welding cast manifolds on older vehicles (1940\'s) before, it aint pretty and is always trouble later down the track.

I opened up an old TD05H-16G that I had lying around to inspect its internals and found these unusual marks on the inside of the turbine housing, anyone seen this kind of thing before? Wondering if its usable or only fit for the scrap bin. I tried to take the best pic I could, still might be kind of hard to see what it is...I know it looks like pitting but in some ways it remind me of a weld that has been ground back as it feels slightly raised when I run a finger nail across it, but surely no! When I\'m back at work I might give the whole thing a good bead blasting and maybe put a bit of engineers blue on that area, that might show it up a bit better.

just my .02c on the subject: Since all the 16g\'s that are currently available are \'Big\' or \'Evo3\', basically with the 18g 68mm compressor exducer, and your standard one (I\'m assuming its factory original here) would have been \'Small\' with a 60mm compressor, you\'ll notice with the big 16g it will arrive at full boost a lot later, you might say it feels \'laggier\'. Sure, the big 16g is supposed to better for top end, but without the supporting mods and the correct tune it just wont be as drivable in my opinion. I think on an early EJ20G street car, you\'ll miss that quicker spooling small 16g for sure. Definitely don\'t get a 20g without the supporting mods, it would probably be a total slug under 4500rpm and way laggy for the street. Now I\'m no expert here, just speaking from experience as I made a similar mistake... I have a BD5 Legacy that I converted to single running a 6S (v3 STi) ECU and used a front entry TD05H-16g \'big\' (basically all stock looking v3 STi under the bonnet apart from the turbo), whereas the turbo that fits that ECU\'s tune is a quick spooling roller bearing IHI VF23. Don\'t get me wrong, it goes alright - just that its a bit flat in the low to mid range rpms. Considering these 68mm compressor wheels really start to come alive around 18+psi, I really have to push the limits of the 6S ECU to make the most of having this turbo...not to mention pushing the limits of my stock block etc, so not really great for a reliable daily driver. I never thought I\'d say it (must be getting old) but I actually want to downgrade to the small 16g to better maximise my tune/setup. Bit of a long post sorry, and maybe I\'m comparing apples with oranges (my heavy and tall geared legacy vs your WRX) but I thought it would be worth mentioning so you don\'t go buy the first turbo you see like I did.

Interesting...do you think the block would be useable for an OEM type build with that flaw? I haven\'t shown my engine builder either the piston or the bore yet as he is away on holiday, he may say \'yep just go ahead and use them\' .

No the damage to the piston is at the 12 o\'clock position and a few smaller marks either side, viewed as fitted (R mark at the top and arrow pointing fwd) whereas the crack in the bore is at about 10 o\'clock.

Couldn\'t find the old head gasket, but here is a shot of the area on #3 where the crack is. Its in about a 10 o\'clock position when viewed looking down the bore with the engine level on a stand. This was supposed to be my \'good\' block in which to rebuild with

Yeah I never thought of detonation, I just assumed it was damage from ingesting a foreign object, although the corresponding area of the bore is perfectly clean and free of any damage. Saying that, after examining the block a fit further - I found a small crack in that same cylinder (approx 8mm) between the machined ring that sits on top of the liner, sorry I don\'t know what that part is called!

Yes the Wiseco\'s I was looking at (P/N K576M925) were 92.5mm and stated 7.8:1 CR. Like Koom just suggested, I originally had planned to rebuild the v2 block with a factory internals as the bores looked so good, looked like it had just been honed , from memory the car had only done 80 odd thou when removed with BEB failure. I was going to use the factory v2 forged (or some say semi forged?) pistons, but what put me on the track to use AM forged pistons was this little beaut here... Shame really.

Thanks guys that\'s all good advice, and gets me going in the right direction. As far as expectations go, I\'m really after just maximising the factory tune of the 6S ECU and to build something that will see me thru for another 10 years ;D (yes has the old RS for over 10 years now and not planning on getting rid of her anytime soon). I understand what you saying about future proofing there rex-leggy, but I have a shed full of other projects too so have set myself this realistic limit on the daily driver for budget/time constraints. Titan has made a good point too of fuel - 98 and the occasional limp home on 95. Economy, a daily work taxi so need to be realistic - basically If I can achieve a \'factory\' type refreshed engine in the guise of a v3 STi, with the parts that I have available, then I\'ll be a happy man. So just out of interest what \'should\' the CR of the v3 STi be?

Cheers Marc, Good call on looking at the piston options, I was looking at Wiseco at first (just the first one I came across in a search), but they don\'t do a standard bore for the pre 98, only 92.5 and 93. What brand of pistons do you use/can recommend? Block I intended using is open deck, although I have a closed deck sitting around also, but that is a bit suspect as it may have been overheated badly, haven\'t checked it out yet. I didn\'t go down the route of using a closed deck block as from what I\'ve read (internet of course) they\'re really only useful when it comes to big HP, also other folks have recommended to not use the factory rods in a rebuild. I guess that is the problem with gaining knowledge from various forums, there are so many conflicting opinions. Yes crank is off another engine, no scoring on the journals and will mic them when I get a chance to ensure they\'re still in spec. Didn\'t mean no disrespect with the \'experienced\' in the title, you obviously know what you are talking about, just wanted to get the attention of guys like yourself that had actually rebuilt engines before.

I\'ve got a BD5a Legacy, original EJ20H converted to single turbo running a 6S ECU, 440cc injectors etc (all standard v3 STi stuff), with a TD05H-18G. It goes reasonably well running on 1bar (on boost approx. 3200k), but I\'m not convinced the v3 STi tune is well suited to the old EJ20H, plus its done almost 200k so I\'m looking at a rebuild. Not looking for huge power here, just a reliable street engine producing close to (or maybe a bit more) what the v3 STi tune is good for. Now I\'ve collected a few parts over the years and I\'m thinking of putting them to good use finally, rebuilding a spare engine while I keep my daily driver operational. There\'s a v2 STi EJ20G that\'s run a bigend on #2, crank and bores are good but one of the pistons (factory forged) has some score marks on the top land, from possibly eating a compressor blade at some stage in its life. Next I have a set of EJ20R cylinder heads that are in good condition, apparently \'reconditioned\' before the engine they were attached to met its demise. I\'m hoping these will be a better match the v3 STi tune than the 20G/H heads I\'m running now, would that be fair to say? Now my plan here is to rebuild the short block with some new forged pistons (Wiseco?), new H beam rods (Eagle?), ACL bearings, Cometic head gaskets etc. My question is regarding selecting the correct combination of piston for compression ratio and head gasket thickness. I\'ve done a bit of internet research but I can\'t get a conclusive answer on the original CR of the v3 STi, was it 8:1 or 8.5:1? what about taking into account the differences of the EJ20K and EJ20R heads when working out CR? Not wanting to go to all the trouble of rebuilding an engine only to find out is all out of whack because I didn\'t get the CR right, I\'m asking for some advice from guys who may have done this combination before.

Yep that's me! Hope all is going well with your adapter harness.

Yes it's the same, I used that 5W to test the single turbo adapter I made for my BD5.

What were the errors?

Is there anyone in the local Wellington area coming up north, going to or passing through Hamilton in the next few weeks? I'm looking at buying a 6 volt car battery from Trade Me, pick up from Raumati Beach, Paraparaumu. Because its a battery they wont courier it so its pick up only, been after decent cheap one for ages now, they are bloody hard to find second hand and waaay too expensive brand new!

That's a good point. I know a guy that rolls around in his auto BC5 RS with the FWD fuse (in or out, I cant remember) and it uses a lot less fuel than my manual BD5 RS single turbo around town, so it just got me thinking...

Here is the original Trade Me listing I saw... http://www.trademe.co.nz/Trade-Me-Motors/Car-parts-accessories/Subaru/Gear-boxes/auction-342149649.htm

Just make sure you disconnect the battery first!

Cheers for your input guys, that clears up my question I think. I was hoping there would be a box I could build up so that I could select just FWD for use around town (for economy reasons) and then select 4WD for when the need called, but if there is no differential between the front and rear when in 4WD then that wont be such a good idea for tarmac use. I wonder also what the centre diff arrangement is like in the auto boxes, how is the drive disconnected from the rear?

So like old Old Skool Subbie said it is locked when in 4wd, so no centre diff?

Very interesting... So how does it work? Is there some type of clutch next to the centre diff to disengage the rear output shaft?

I must have been dreaming when I saw this box then It was definitely a manual box, looked like an average TY752 but the rear housing was slightly different. It wasn't a front wheel drive box either, this one had an output housing. I'm starting to think this could have been a dual range box and the guy selling it may not have known it was permanent 4wd, and was assuming it was selectable between 2wd and 4wd. Thanks for your input anyway guys.

Who's heard of or got one of these in their Impreza? I saw one on TM a while back (now I cant find it, typical) and it took my interest for a project I'm working on. It was definitely from a GC/GF Impreza, and was selectable between front wheel drive and four wheel drive.