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can i turn this into a 2.5???????.....

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Old 26 September 2010 | 09:11 PM
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Default can i turn this into a 2.5???????.....

Hey everyone!

Right so after reading dazdavies thread, and cataluyna172s (etc etc)...
i found myself again on the internet buying things for my scoob!!!HA!!
But it also got me thinking - "is 2.5 the way to go????"

Now my current engine spec is as follows;

Fully forged STI engine,
Omega forged pistons,
Manley H Beam forged conrods,
V9 STI Nitrided crank,
Piper cams,
ACL mains and big end bearings,
V3 STI ported and polished cylinder heads,
Nimonic exhaust valves,
New timing belt and tensioners,
Lightweight flywheel and pulleys.
TD05 16g Turbo. Built by BGV Engineering

So being someone with limited knowledge of the complete inner workings of an engine - can someone tell me what i would need to turn this into a 2.5 litre monster?????

Surely its not just as easy as replacing the bottem end with a 2.5 and fitting a 6speed box right?????????????????????


Many thanks
Andy

Last edited by ClassicWR1; 26 September 2010 at 09:21 PM.
Old 26 September 2010 | 09:16 PM
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From: Rl'yeh
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Not sure either you'd want to, or that it would be cost-effective.

Tyhe 2.5 gives you more torque, which pretty much makes the 6 speed mandatory, unless you want to see your 5-speed box stripped.

But what you have, above, would seem pretty bomb-proof anyway?
Old 26 September 2010 | 09:37 PM
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I prefer the 2 litre set up. Ive never driven a 2.5, but i like the way the 2 litre revs. Your set-up looks a far better set up than a standard 2.5.
Old 26 September 2010 | 09:50 PM
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to be honest guys i thought the 2.5 route would be better if i ever decided i wanted to go big BHP(500+)???? Surely torque is not the only benifit right??

I mean if the 2.0 set up is better why would people go with the 2.5 in the 1st place guys????

Regards
Old 26 September 2010 | 10:07 PM
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The 2.1 stroker seems to be the weapon of choice at present, with some good results.
Old 27 September 2010 | 09:26 AM
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Doesnt the 2.1 stroker kit consist of uprated pistons/ crank/ bearings etc that mine already has though??? Or do i sound a complete newbie here???LOL


Can anyone else shed some light on this (or my original question) for me and put it into laymans terms pleeeeease?????


Many Thanks
Andy
Old 27 September 2010 | 11:33 AM
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To go 2.5 from your current setup, you need to ditch your bottom end and buy a EJ257 block and start again from scratch as in new forged pistons and rods especially if you are going over 450bhp.

Banny
Old 27 September 2010 | 12:51 PM
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So i would need to start from scratch with new pistions etc would i???? Is that because i would need the bigger type???

Someone i was speaking to yesterday (Mr I know everything about cars!!lol) led me to believe it was just as simple as swapping bottom ends and obviusly the gearbox????...
Old 27 September 2010 | 01:06 PM
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Depends on your power goals the standard 2.5 bottom end is good up to 400bhp above that you will need to forge it.

Techincally speaking "Mr know it all" is correct as you remove your EJ20 (92mm bore 75mm stroke) bottom end and replace it with a EJ257 (99mm bore and 79mm stroke)

So it is your call, personally I would stick with what you have and if more power is required bigger turbo and gearbox is all that is needed. I am running 523bhp on a 2 litre bottom end.....
Old 27 September 2010 | 01:09 PM
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From: Slowly rebuilding the kit of bits into a car...
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You will end up needing a block, crank, forged rods & pistons, your heads ought to be machined to suit, but very thick head gaskets might "do"...

Then your clutch may need replacing when you fit the six speed...

Just enjoy yours, the 2.5 creates much more low down torque, but don't generally like high revs as much as a 2 litre. ( Unless you invest large amounts of cash ).

A lightly dusted 2.5 makes a lovely road car, IMHO.

But I fancy a 2.1, more grunt and still a healthy appetite for revs too !

dunx
Old 27 September 2010 | 01:11 PM
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The TD05 16G on the 2.5 is going to be a bit asthmatic

Shaun
Old 27 September 2010 | 02:52 PM
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Thanks guys!!! now thats exactly the info i wanted to know(in simple laymans terms for me aswell thank you!)!!!

So really there is no point in doing the 2.5 neway i see, 500+ bhp on a 2litre....
WOW!!! could really scare the Mrs with that!!!!he he


Again, thanks for the replys everyone!
Old 27 September 2010 | 10:40 PM
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From: Enginetuner.co.uk Plymouth Dyno Dynamics RR Engine machining and building EcuTek SimTek mapping
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Originally Posted by ClassicWR1
Thanks guys!!! now thats exactly the info i wanted to know(in simple laymans terms for me aswell thank you!)!!!

So really there is no point in doing the 2.5 neway i see, 500+ bhp on a 2litre....
WOW!!! could really scare the Mrs with that!!!!he he


Again, thanks for the replys everyone!
You pretty much have everything there apart from the turbo.
S206? 500 bhp capable.
Old 27 September 2010 | 10:57 PM
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Alan Jeffery
You pretty much have everything there apart from the turbo.

S206? 500 bhp capable.
Do you mean with the engine i have already bud???

Bigger turbo, injectors and a gearbox yes????

Just out of curiosty mate, whats different to mine and one of these 2.1 stroker kit????


Regards
Andy
Old 28 September 2010 | 07:18 AM
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From: Enginetuner.co.uk Plymouth Dyno Dynamics RR Engine machining and building EcuTek SimTek mapping
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Originally Posted by ClassicWR1
Do you mean with the engine i have already bud???

Bigger turbo, injectors and a gearbox yes????

Just out of curiosty mate, whats different to mine and one of these 2.1 stroker kit????


Regards
Andy
The stroker uses the 2.5 crank with different rods and pistons. The upshot is more torque and the ability to handle a bigger turbo. The results speak for themselves!
Old 28 September 2010 | 09:48 AM
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oh i see!!

But as my engine is currently at the spec it is, really there would be no point right????

Thanks again for all the info everyone!! Much Appreciated


Andy
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