Subaru, engine weight

[Incorrigible]

I've got a little mid engine project I'm working on. And we're having a load of arguments on the power plant..

The idea of using the impreza lump has been bandied about, low centre of gravity, loads of tuning parts available, etc etc. But one of us are hugely familiar with them

A couple of questions:

How much do they weigh ?
How easy and cheap to get ~270hp ?

Other options are bike, or have the engine mounted transversely a la atom, but we don't really want to do that

Track car, obviously

[stevieturbo]

no idea on weight, but given their nature would be lighter than most engines of similar performance

All alloy, crank by design is very light etc That alone would be a good saving over inline engines where the crank is typically very heavy

And 270bhp is very easy.

[mulfab1]

Benjamin- Ive got a mate whos putting one in the back of his panda for trialling
I'll give him a tinkle if I remember tomorrow and get him to stick it on a cornerweight scale

Simes

[anonymous-user]

They weigh pretty much the same as most 4cyl 2litre engines as they have 2 heads (rather than 1) and long exhuast and intake systems. iirc dry weight for a fully dressed one is about 165kg (turbo,manifold, flywheel, starter, alternator, loom, fuel rail/sys etc)

Also, although the engines centre of gravity around it's crank is lower than for an inline4, by the time it's installed in a vehicle with enough space underneath for the exhaust the CofG is the same!


(even for the WRC car, this was the major downside (and why the scoob never really got close to the Citroen/Ford, esp on tarmac)


but, it's a good choice for a kit car, cheap, availible, tunable etc and certainly good poke for your pound ;-)

[Pumaracing]

270 bhp turbocharged or normally aspirated? Easy enough with the former. The Subaru engine has big valves but terrible ports. These respond massively to being reshaped in the appropriate places and adding 100 bhp plus to a high boost turbo charged engine is not that hard to do. As they used to say on Blue Peter "here's one I did earlier."

http://forums.sidc.co.uk/topic/123572-charity-rr-d...st20

Post #36 with the dyno results. The 514 bhp 428 ft lbs one at the top of the Imprezza table is the one I did the heads and block for. Prior to that it had struggled to make the 350 bhp that most of the others you see there were aiming for. The ports really are that bad and there's a limit to how much power you can get just by trying to ram more boost and heat through the engine.

[stevieturbo]

The ports in later engines are much better aside from the exhaust ports on the rear cylinders which are still awkward.

Achieving 4-500bhp on standard 99/00 heads is still very easy though, although obviously rods and pistons will need to be suitable for that level of power.

For 270 though, even a bog standard 99/00 UK car on the tiny TD04 can achieve it and will be very responsive. No need to touch the engine at all for that.

[Incorrigible]

Cool, thanks guys.

I don't suppose anyone knows whether the engine/'box mounts are the same through the range. So I can build it with a single cam (that I have) and bung in the proper engine when (if) the chassis is up to scratch. Or any other dimensional differences through the range

[stevieturbo]

Incorrigible said:

Cool, thanks guys.

I don't suppose anyone knows whether the engine/'box mounts are the same through the range. So I can build it with a single cam (that I have) and bung in the proper engine when (if) the chassis is up to scratch. Or any other dimensional differences through the range

All mounts are the same. And the only real dimensional differences are the fact the quad cam heads are bigger. Overall though, there isnt much difference.

[Incorrigible]

Cheers Steve, I thought as much