rossi_p

iTrader: (26)

Gents,

I’m after some views from those in the know.

My engine is just being rebuilt due some problems with the previous build and I’m interested to know what power people think my engine can take reliably. By reliable, I mean that it is running well within its limits, can run that power all day and with regular servicing easily be capable of running for 60k+ miles minimum without the requirement of a another rebuild.

Ej22t cdb with piston squirters.
Modified (drilled for better oil supply) 2.5 Sti forged crank.
Pauter 4340 forged rods.
Side coated CP forged pistons.
ACL big and main end bearings.
Cometic head gaskets.
11mm ARP studs/bolts.
V4 Sti heads and cams.
Titanium valves and springs.
Bronze valve guides.
Alloy pulleys (crank, alternator, PAS).
Oil cooler/Oil catch tank/Modified oil pump.
PE Kevlar cambelt.
Baffled sump.
Manifold spacers.
Carl Davey insulated fuel rails.
Fuelab FPR.
Goodridge 811 hose & fittings.
Walbro lift pump, swirl pot, Bosch 10 bar inline pump.
Hybrid FMIC.
Tubular headers.
Revolution 3” exhaust.

Basically, I’m trying to decide which turbo to go for.

I’m not number chasing, I just want to build the best (read reliable) engine I can with my money but without selling it short.

Note I have a PPG straight cut, Exedy twin plate and appropriate brakes/suspension so they are not (to a point anyway) a restriction.

Many thanks for your views!
Ross

banny sti

iTrader: (68)

Stick a MD321V on it and 500/500 all day long reliably, would also consider upgrading to 14mm headstuds for peace of mind

Banny

rossi_p

iTrader: (26)

Thank Banny

I did think about 14mm studs but even up to 600bhp, surely they are overkill?? How much more clamping force do they really offer?

V is the main contender but have a T at the moment... worth considering a rotated GT35R.. ...

frayz

iTrader: (7)

Im in the middle of all this rotated malarky mate.
Dont get me wrong. Ultimately it will be marginally better than a MD321V...

By marginally i mean, marginally.

If you plan on using the car alot and just enjoying it. I think there will be little more need than 500/500 on a road car. Some guys with more ponies may think that you need more than that on the road , who knows?

However, lets not lose sight of the fact that a 500bhp car is rediculously fast, i think its the very fact that 500 is becoming more commonplace that we decide its not enough and think we need more. Kinda keeping up with the Jones's.

Step back and ask yourself seriously, how many 500bhp cars are out there on our roads with the kind of performace a 500bhp impreza has?

Not that many im sure.

I would deffo stick with the idea of the V and not going rotated, it simply isnt worth the cost vs gains at those levels. I also dont think the 14mm studs are needed at those levels.

rossi_p

iTrader: (26)

Thanks for the advice Frayz..

There were some fundamental problems with the previous build meant it was underperforming with the T anyway. With that in mind I'm seriously considering sticking with the T as will feel so much better than before.

I will have to buy a new downpipe/uppipe and considering the re-sell value of the T (with blanket, oil/water feed), plus the induction/inlet parts I can sell as well, I was wondering whether the net cost of buying into rotated land would be worth it?

Personally, I was thinking 450/450 is more than enough and after some recent rolling road results (which partly led to the decision to take it apart) a jump up to 450/450 would be sufficient.

frayz

iTrader: (7)

Your call mate, personally id go with the V anyway and be sure i had ample headroom if i wanted to turn the wick up some more.
The V will make the same power at less boost, and theres no doubt in my mind the extra lag will be marginal over the T.

Id rather have the V making the power with less effort than having the T near its limits.

Your call though fella.

rossi_p

iTrader: (26)

Thanks for the advice.

Agree the extra headroom would be nice, that was the idea behind going rotated.

The start of the thread was to decide if my engine could happily take a bigger turbo than the T... I'm guessing you all think it can.. easily.

Now just got to decide which one

al02uk

iTrader: (1)

Your engine wouldn't happen to be sat on the build table next to mine by any chance

Did you decide not to go for the Crower cams in the end?

Andy

frayz

iTrader: (7)

Looking at the spec Ross, if i built it myself and speced the clearances, id personally be happy to take it to 500+ of each.

You havent listed an oil pump? im guessing an RCM item?

Only thing i dont like is the drilled crank. (depending on what exactly has been done) as i believe it weakens them and provides little increase if any to oil supply. Sometimes it will reduce pressure too.

But that a personal thing.

al02uk

iTrader: (1)

Frayz,

What is your opinion on the GT30 in the standard location? (assuming a GT3076R is a GT30, I'm not sure).

The reason I ask is that I'm doing something similar to Ross, I have spotted this and its cheaper than the MD321V

Andy

frayz

iTrader: (7)

You'll find it very difficult to put a GT30 in the stock location mate as its not a stock location turbo. The exhaust housings are Garrett and will not fit the subaru up/downpipe. Also the GT30R generally comes with a 4" inlet which means you will not get a 4" inlet hose inder the stock manifold.

It may be a cheaper turbo in initial purchase but will cost you twice as much to get fitted to your car. Plus you will need an external wastegate as the GT30r is not internally gated.

frayz

iTrader: (7)

Heres my GT3076R so you will see why it has to be rotated and wont fit in the stock location.







Here it is in the engine bay, for size reference.

al02uk

iTrader: (1)

Ah right, thanks for the info mate.

Have a look at this link

GT3076R Turbo Kit for Subaru WRX/STI, stock location : atpturbo.com

Have you seen this one used before? its claimed to be able to do 500bhp, I thought this was a GT30 for some reason.

al02uk

iTrader: (1)

Christ, that is miles different to the one in that link, that inlet is massive!

frayz

iTrader: (7)

Sorry for the thread hyjack Ross.

Al, the one in the link is just ATPs answer to our GT30 based turbos. All they have done is squeezed the GT30R cartridge into the stock subaru exhaust housing. Yes they may still have the 52lb per min compressor wheel of the genuine 30r but they never work or produce the results of a genuine Garrett unit using the proper Garrett housings.

If i were you id get an MD series turbo from Lateral. Theyre tried, tested, work and you have proper customer service based here in the UK on your doorstep.

Duncan, (dynamix) is chucking out over 485bhp on pump fuel and 540bhp on E85 on a built, but otherwise stock 2.5ltr STi.

(i say otherwise stock, as it has stock heads and cams etc)

frayz

iTrader: (7)

Please bare in mind.. not all 52lb per min turbos are the same... use one that is proven. By proven, i mean by producing the results on a number of different engines etc.

al02uk

iTrader: (1)

Apologies also Ross.

Thanks Frayz, makes sense. I'll probably spend a bit more time saving for the MD321V then.

Andy

al02uk

iTrader: (1)

I see what you mean, the one on that link claims to do alot but there is no graph or dyno read out to be seen anywhere.

frayz

iTrader: (7)

Alot of turbos claim to do alot of things mate. But the people that write these things are the guys trying to sell them.
Have a look over on the NASIOC and see whos using the ATP unit and whos using a genuine 3076R. Then compare the results.
Also have a look about in the UK and see whos using what turbo on what spec engine and compare the results.

If you dont want more than 500bhp or super quick turbo serviceability ie for race/competition applications. Rotated setups simply are not worth the money or time invested for the minimal gains you will see.

al02uk

iTrader: (1)

I definatley don't want to go over 500bhp. I'm hoping that my rebuild will be the last just as Ross does.

I've only ever heard good things about the 321V, API who are doing the build also recommended it. I was just a bit shocked at the price. I don't mind saving for it though.

frayz

iTrader: (7)

I agree its expensive circa £1600 from memory

Rotated

Turbo = £1000+
Wastegate = £400+
up/downpipes = £800+
Airfilter/silicone coupler = £200

Dont expect any change whatsoever form £2500 lol

Jay_

Nice build you have there Rossi

My initial thoughts are that you've never quite had the T performing on your previous build, so not quite experienced what a T can truly deliver on the road. Now you have a v nice 2.3 build on its way... bolt a fully functioning T on to that and you will have a very serious road weapon I'd be tempted to map it all up on the T first and see how you like it. If it's not up to what you want then look at the V. Jumping straight to a V is a huge step-up mate... from experience its always nice to mod your car gradually rather than doing mega-power jumps

I run about 450-480 on my 2.35 and use it as a high mileage every day runner. It's awesome and I would have to give it very careful consideration before going the next step of something like a V....which probably means spool sacrificed for headline power.

Try the T and then the V if it's not enough

Jolly Green Monster

iTrader: (4)

Rossi,

If you want a passenger ride in a 2.35 running a V let me know..

Glad you are sorting it.. that engine was just never right imho.

Simon

banny sti

iTrader: (68)

Agree with what Jay says a T running at its full potential makes for a cracking turbo. If you wanted a little more out of it you could map for methanol or E85, if you have any local to you. Rotated route gets very expensive when you factor in all the little bits and bobs but it does sound good

Banny

rossi_p

iTrader: (26)

Thank you for all the advice!

Banny / Jay - I think you're both right in that I should probably stick with the T and see how I go.

Andy - I think we are indeed built brothers . Unfortunately, those cams wouldn't fit so other options are being investigated but we will see.

My hesitance with sticking with the T was that I would have to buy a new up/downpipe and then, if I go rotated, have to buy all that stuff agaion.

But, as pointed out by Frayz, the V offers more than enough from a standard location turbo. Cheers fella, I followed your advice on the V3's and couldn't be happier with those.

Simon - Thanks for the offer, I think I will take you up on that! There are quite a few problem with the build that I will tell you about next time I see you.

frayz

iTrader: (7)

Hope it all goes will Ross, keep us posted fella

Aztec Performance Ltd

iTrader: (234)

Would seriously consider the S206 too. Great results both on the dyno and strip.

Am going the same way as Frayz myself.