Advice on part selection for type 4 turbo

[qaxa]

Hello,

I'm planning on building a type 4 turbo motor for a bus and I would need some guidance on part selection:

Should I bias towards thicker wall cylinders vs bigger bore? I.e. 96mm with JE's instead of 103mm with JE's? By the way are there "better" piston options available as I read from here that 2618 aluminium JE's are a bit on the soft side? Is this correct? If so, which are better alternatives?

I have understood that a 78mm crank doesn't need any clearancing, correct? How much clearancing is needed for a 82mm crank?

If you were to build this engine would you go for chevy or T1 journals?

So a 78x96, 82x96 or a 82x103 or perhaps something else? Nickies would be nice but they are too expensive at this point. Any experience with QSC aluminium / nikasil cylinders?

Would a web 86b or a web 86a cam be a suitable choice for a bus?

Heads are from an 1.8 AP and how does 44x38 valves as a plan with a mild porting job sound? Or is a 44x40 a better choice as the exhaust is the restriction with these heads and turbo will take care of the intake anyways?

HP goal is in the region of 300hp and E85 fuel to be used. I already have an ECU and a single TB with water intercooler is in the plans.

I would rather cry once and buy the right parts instead of cutting corners. Can I expect any kind of longevity from such an engine in a heavy car without nickies?

Also as this is going in a '73 T2 so I should retain the original pancake shroud? Original design is pretty effective as far as I've understood? No real benefit going to cali-style for example?

[neilb]

what turbo are you buying? how much boost? exhaust housing size? turbo's produce heat and lots of it. i'm not knocking turbo's i love them, you know the saying ''aint no substitute for cubic inch's'' compressed air! is my reply... i ask these questions as its important to have a clear well thought out plan. after building water cooled turbo cars, i asked a (lets just say guy) about achieving 300hp from a type 4 engine and he pretty much laughed. this is while he was standing next to his turbo type 1 race car which he said had around 600hp.

after speaking to a few guy's that know type 4 engines, and reading plenty, torque is what you want. plenty of it, from just off idle to around 5k rpm. usable power.

few guys have built turbo type 4's i'm sure they have some good info.

[Clatter]

You never see a bored/stroked bus motor because the cooling can't hardly dump the heat made from a stocker.
Never mind a turbo...

If you want 300HP from a bus, get a motor with water and a radiator.
JMHO.

[qaxa]

You never see a bored/stroked bus motor because the cooling can't hardly dump the heat made from a stocker.
Never mind a turbo...

If you want 300HP from a bus, get a motor with water and a radiator.
JMHO.

There are a few even on this forum: viewtopic.php?f=3&t=106129&start=450

No idea on how long they last though? Unfortunately water cooled engine (basically Subaru engine) is not an option due to legislative restrictions we have over here.

I've been thinking about this a bit further and perhaps best bet would be to keep it 66 x 96 with good pistons and just lower my power-goals to a more reasonable level and aim more towards torque. E85 helps quite a bit for the cooling part though.