martyrobertsdj

iTrader: (1)

I like most other people on here would like more power, so I've been looking at my options.

1. Drive in-drive out 450bhp works out about £9000
2. Drive in-drive out 400bhp works out about £4000
3. Drive in-drive out forged bottom end rebuild works out about £2600

Now this got me thinking. I'd like 400 bhp, but 450 sounds better doesn't it I'm not hooked on pub talk power figures, but would like to have a solid bottom end that could withstand these sort of power levels with relative ease.
I am now thinking that over the winter I normally take the car off the road anyway, so could maybe rebuild my existing motor using forged pistons, new rods, bearings, etc. I would then have a bottom end that could be good for the power levels as and when I buy the rest of the components to produce them.

I could probably build a rock-solid motor to produce 450bhp for the price of a drive in-drive out 400bhp....whadda ya reckon?

I am wondering whether I can just buy "drop-in" forged replacements for my existing pistons, rods etc, or am I going to need to consider rebore/honing, etc? The car has only done 30K miles, so won't need a rebore for wear reasons...I'm just thinking it may need it to match bores to pistons, etc??

How complex a job is a rebuild? I'm a time served technician and have rebuilt a couple of engines before, but nothing as complex as one with variable cam timing, turbochargers, etc.

Are there any high quality manuals for rebuilds?

Maybe I should get a big box in my spare room, and then slowly fill it with all the parts I'm likely to need to to complete the works (including producing 400-450bhp) and then hit the job all at once??

I call upon those with such experiences to impart their words of wisdom Thanks

alanbell

iTrader: (6)

0h Marty, if this was me i would put a fmic , better turbo , remap should be near 400, then if and when it breaks do the engine build, good luck , Alan.

dunx

iTrader: (3)

Agree, a big turbo, an fpr or bigger injectors, and (optionally) FMIC plus a re-map should get you close to 400 bhp.

Mine is soon !

Just waiting for an the Exedy to be fitted, that will take the extra torque !

DunxC

alanbell

iTrader: (6)

afaik martys sti injectors should be ok for 400+

martyrobertsdj

iTrader: (1)

lol...it's the "when it breaks" bit that I don't like the sound of.

I've been looking at 400bhp as a target, but then if it breaks, I have to rebuild anway, so why not go for the rebuild first and then it "shouldn't break".

I will need a new turbo for 400bhp and then if I choose to go for 450, I'll need yet another one, so that sounds like uneccessary expense.

Also, if I rebuit the engine as is now, I know it's in good condition, so could probably get away with the minimum amount of parts; if I wait till it pops, then knowing my luck a rod would go through the block, a valve would damage the head and the turbo would be damaged too; I'd then need a lot more parts to rebuild = even more expense.

Rick is going to give me an idea on price for a "400bhp kit", so when I get that price it may sway me in one direction or another.

mshill

iTrader: (4)

9K is alot of cash for 450 bhp

Agree with others, Fit a New turbo, front mount + supporting mods and you will see 400bhp.

My m8 got a year out of 450bhp / 410ft,lbs.
Engine now getting rebuilt before it goes bang

STI_Baly

iTrader: (23)

Marty i'm not to sure if you have a 2.0 or 2.5 under there but if a 2.5 it's pretty much rock solid upto 500bhp. Obviously i know exactly where you are coming from as i have a Ej257 which i will be forging fully before i go any further with it.

Only because i have 2.0 CDB in mine already and she runs. If i was in your shoes i would definitely stick to what the lads are suggesting, as i feel that is extortionate amounts of money for only that power level.

Good Luck

Baly

martyrobertsdj

iTrader: (1)

Mine's a 2.0 with chocolate pistons

A bit unfair to say "chocolate", but from all I've read, the pistons seem to be the prime limiting factor for outputs over (depending where you read and who you believe) 400-420bhp.

I was just thinking that pistons and rods would make it "safe" for 400bhp and beyond, and that if I did the work myself, I'd save wads of cash.

I'd just need a quality manual and/or the advice of others more experienced than I in the way of the flat 4 from Subaru.

dynamix

iTrader: (3)

The cost rise dramatically over 400bhp.

If it is just for the road - stick at 400bhp limit.
If you feel the need to go over 400 then why not go for 500 - the main bulk of the expense is getting over 400 in clutch, flywheel, fmic, new turbo. These extra bits, hoses, clamps, adapters, gauges, sensors etc add up to a lot.

On an EJ257 block:
Drop in pistons should do you 450
Drop in pistons and rods should be safe for 475
Things start to get really expensive beyond that.

If you want to go for 400 (and in your position, I would) - stick an MD321H - will hit that target easy and be great fun to drive. It is also readily sellable turbo should you feel the need to upgrade to the T version on a built engine later. They hold their value very well from what I have seen.

martyrobertsdj

iTrader: (1)

So...are you saying fit a 321H and supporting mods like injectors, FPR, etc and stick with my stock bottom end and aim for 400bhp?

Sounds good to me like lol.

As you say, 400bhp is plenty enough for the road and if I did want to go further in future, a bottom end good for 500bhp probably won't cost a great deal moe than one for 450bhp.

Shopping list time.....MD321H, 650cc injectors, FPR..........is a FMIC essential at this power level??

finchyboy

Just had a similar spec motor built 2.5 with wiseco drop in piston's on standard rods should be good for 400 +bhp.

The next stage 450 bhp would prob need steel rods

500 bhp would be both of the above and to be on the safe side a having the block relinered would be advisable.

So there is quite a bit more expense to go from 400 bhp to 500bhp.

dynamix

iTrader: (3)

Yes.

You should be okay without an FPR if the injectors are the right size. say 650cc versions.

FMIC is not essential unless on track a lot IMO.

DC Customs

Im selling a MD321T at the mo, in the for sale section. Only done 400 miles so as good as new! Also going to rebuild my 2.5 bottom end in the next month that just blew a piston. This has crower rods, ARP 11mm studs, Wisco pistons so is good for 475bhp and more. Not sure on price at the mo though.
let me know if your interested but going second hand is always a good way to keep costs down. I was running this at 486bhp with 800cc injectors. Only just got it run in though before it went pop on the dyno.

lunar tick

iTrader: (2)

I'm running a standard 2003 STI engine with 321H, 650 injectors and TMIC (plus usual supporting mods such as good exhaust and tubular headers). Mapped on methanol it makes plenty over 400bhp and is a hoot to drive. I've done over 25000 miles at this level now and (touch wood) engine is still as sweet as a nut. Whereabouts are you? You're welcome to come a for a blast in the old girl if you ever in this area

martyrobertsdj

iTrader: (1)

Hmmmmm......sounds tempting

I'm over in East Yorkshire, but sometimes visit mates in Cumbria (Whitehaven), and pop up the Newcastle area quite a bit, so a run across isn't out of the question.

If I'm likely to be popping across, I'll drop you a PM and see if it suits you sir eh??

renno rannes

Sorry did you blow the Wiseco piston or are rebuilding with the Wiseco pistons ?

Any idea what happend ?

DC Customs

Yeah unfortunately it blew a wisco piston which are more than capable of taking this power. Im betting they ran it lean on the dyno, or the boost peaked for a split second, resulting in the damage. Impossible to know for sure though but it was fine before hand. Bit of a bummer really but **** happens! Im going to get it rebuilt with new wisco pistons or at least maybe just the one thats damaged. i still need to split the block to find out exactly whats damaged first. If this works out too expensive I may be splitting and selling on the parts.

MartynJ

We run 3 of these at 440-460bhp on stock internals , 2 on 10%meth 1 on VPower only..
All 3 of them have been like this for 12 months plus without issue..
The STi8 engine is very strong , but I would advise building the engine for longevity and the promise of more to come at higher boost levels..

martyrobertsdj

iTrader: (1)

What turbo are you using for 440bhp Martyn??