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350bhp 2.5 engine


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10 hours ago, Piggysniffer said:

Ok lads n lasses, can you tell me what I would need to do to a 2.5 wrx lump to make a good strong and safe 350bhp, what turbo, piston and/or rods, bearings injectors ? etc etc, am looking at building one hopefully next year to chuck in my hawkeye

Hmm, are you ever going to want more than 350? Because you need to build around the turbo sizing. FP Green could get you to 400 pretty easily. But there's loads of turbo choices. Think someone did a thread in the general Subaru area with a list?

pistons & rods, Weisco pistons, Carrillo Pistons and rods or Eagle rods? ARP if they make them? Maybe check into head studs etc as well.

Injectors at least 800cc probably 1000 I'd say, RC Engineering does good ones.

Bearings, Clevite (spelling?) do the ones for NASCAR so they're good. Or there's good ol' ACL as well.

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440's will run 340hp on a classic so 555cc sti injectors will reach the 350hp target easily but you get bigger injectors you'd always have headroom for a power increase when "project creep" sneaks up on you [emoji23]

I'm not sure what the limit is for a standard 2.5 ltr block tbh . Afaik you'd be fine @ 350hp with standard rods with just uprated pistons to rid the Ringland curse .

But yet again if your gonna spend the time building it and the money on gaskets for the rebuild you might as well go for a bit more headroom ....

Cossie/rcm headgaskets.

Uprated headstuds and pistons.

H or I beam rods .

Most use rcm or g goode oil pumps and acl race shells.

I think "pinning " might be a bit cheaper than cdb inserts but I'd go the whole hog and get it cdb converted if I was gonna build a 2.5 .

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my wrx hatch is 320bhp, for the roads i think it has enough

3" decat

VF52turbo,from what i have read its off a new shape forester so intercooler can bolt straight on to it instead of a hose like sti,also read late wrx's had same turbo?its the same as a VF39 but the 39 uses a hose for intercooler and suffered boost creep.

front mount intercooler

RCM 340 fuel pump

 

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my mate in the States ran a FP Green, and a full turbo back exhaust and had t mapped on a hawkeye STI for years with no problems mind and I'm pretty sure he was pushing 400 horsies. They don't need too much to make decent numbers from what I've read.

3 hours ago, savage bulldogs said:

440's will run 340hp on a classic so 555cc sti injectors will reach the 350hp target easily but you get bigger injectors you'd always have headroom for a power increase when "project creep" sneaks up on you

Why I was thinking bigger injectors 😂 If you're going to spend the dough, get the bigger ones like you say haha

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Standard 2.5 block will run 450 reliably so closed decking is a tad ott. Rebuilt with decent pistons, rods headstuds, gaskets and rebuild.

Plenty of turbos in that range. So depends how much you wanna spend. Personal choice would be sc36. Will run 360 and spool like a rocket.

Need fuel pump and injectors plus inlet pipe.

 

Be cracking on the road with that spec

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I would like to go 1000bhp but I have to be realistic 🙄 I'm not made of money so I have to set myself a target/limit, but in saying that not worth building something that'll just handle 350bhp, I want a car that has a good bit of power for not an extreme amount of money as the credit cards gonna take a broadside to do it lol and I want it to be reliable, would be nice to factor in a bit of leeway for reliability or for a bit of extra power one day if funds allowed, but tbh I can get myself in the mire with 277bhp so 350/60 as tidge says would surely be enough, I don't really have funds for stronger gearboxes so I was thinkin around the 350 mark  would be OK, and doable mo ey wise, would have to do clutch for sure, the wife is cool with it, soon as I've paid the card up I can abuse it for the engine 😜

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1 hour ago, Tidgy said:

Standard 2.5 block will run 450 reliably so closed decking is a tad ott. Rebuilt with decent pistons, rods headstuds, gaskets and rebuild.

Plenty of turbos in that range. So depends how much you wanna spend. Personal choice would be sc36. Will run 360 and spool like a rocket.

Need fuel pump and injectors plus inlet pipe.

 

Be cracking on the road with that spec

Liking that mr tidgy

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Could always wait until we've got a better trade deal with America and buy a blouch (re branded sc ) or fp turbo from the states [emoji6] .

Second hand md based or genuine tdo5 18g would hit the target power for about half the price of a new sc36 .

Or get someone like Owen developments or turbo dynamics to refurb a fubar'd turbo to your needs .

Which is the route I thought I'd take with my £200 aps sr40 (gt28 based stock location turbo ) well when I eventually blow it up [emoji23]

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3 hours ago, Piggysniffer said:

I would like to go 1000bhp but I have to be realistic 🙄 I'm not made of money so I have to set myself a target/limit, but in saying that not worth building something that'll just handle 350bhp, I want a car that has a good bit of power for not an extreme amount of money as the credit cards gonna take a broadside to do it lol and I want it to be reliable, would be nice to factor in a bit of leeway for reliability or for a bit of extra power one day if funds allowed, but tbh I can get myself in the mire with 277bhp so 350/60 as tidge says would surely be enough, I don't really have funds for stronger gearboxes so I was thinkin around the 350 mark  would be OK, and doable mo ey wise, would have to do clutch for sure, the wife is cool with it, soon as I've paid the card up I can abuse it for the engine 😜

you could sell a kidney to get the money :tongue:

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23 hours ago, savage bulldogs said:

Could always wait until we've got a better trade deal with America and buy a blouch (re branded sc ) or fp turbo from the states emoji6.png .

Second hand md based or genuine tdo5 18g would hit the target power for about half the price of a new sc36 .

Or get someone like Owen developments or turbo dynamics to refurb a fubar'd turbo to your needs .

Which is the route I thought I'd take with my £200 aps sr40 (gt28 based stock location turbo ) well when I eventually blow it up emoji23.png

Not the same turbo. Sc are clinic specific. 

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I dare say they're not 100% the same but I'm sure s.c turbos are made by blouch ?

If so I'd imagine you can probably buy 1 close to the spec they provide for s.c .

I just hope we can get better import deals with the U.S , as they seem to have more budget friendly priced aftermarket scooby stuff. Well Compared to the expensive European alternatives that we find over here .

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1 hour ago, savage bulldogs said:

I dare say they're not 100% the same but I'm sure s.c turbos are made by blouch ?

If so I'd imagine you can probably buy 1 close to the spec they provide for s.c .

I just hope we can get better import deals with the U.S , as they seem to have more budget friendly priced aftermarket scooby stuff. Well Compared to the expensive European alternatives that we find over here .

Blouch made, custom billet design core

Slight differences can make a massive difference to performance.

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Yeah I know hybrids make more power than oe spec and I'm not jumping on the "slagging off s.c bandwagon " buddy .

Just the likes of a s.c 42 is a cracking turbo but at nearly £1.8 k delivered I'd never be buying one .

If I did I'd have to sell my sti saloon and buy a leggy estate ,so I could fit a bed in the back [emoji23] .

So I'm always on the lookout for something cheaper too sneak past her radar [emoji6]

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1 hour ago, savage bulldogs said:

Yeah I know hybrids make more power than oe spec and I'm not jumping on the "slagging off s.c bandwagon " buddy .

Just the likes of a s.c 42 is a cracking turbo but at nearly £1.8 k delivered I'd never be buying one .

If I didn't I'd have to sell my sti saloon and buy a leggy estate ,so I could fit a bed in the back emoji23.png .

So I'm always on the lookout for something cheaper too sneak past her radar emoji6.png

Didn't take it that way so no worries, was more a comment as to the difference :)

How much you want to spend very much depends on budget and what you want from it.

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