how much for a 2.5 conversion on a classic
 

i am thinking about doing a 2.5 conversion to my 99 classic in a few months, how much would this cost?

depends on the spec really

as said, you can have a budget 2.5 build for about 4.5k, or you can have a monster for 20k, although if your going that mad then theres better ways to get there.

you either need to decide on a budget, or a power figure

Check Zen Performance - Engine & Ancillaries to get some ideas

id sugest you check out 2lt forged cos the 2.5 has very different charicteristics in the power delivery unless ur after 800bhp in which case youll need a forged 2.5 im sure most would agree ur better of with a high spec 2lt than a standard 2.5 and youll keep the mad surge of power as apposed to a gentle wave my mate had it done and its no where near as quick at over taking as it was considering the bhp is very similar to what it was previously just a thought each to thier own..

2.5's dont tend to have mega high pwer, the 2lts and 2.33's tend to get big power due to them being close deck

IMO....

Looking at your "My Scooby". You've a UK 2000 model.

Depending on budget.... Or assuming some budget limits.

I'd be tempted to go for a modest spec 2.5. With a TD05 or a VF28 you can have virtually lag free power and a similar rev range to that of your current motor, albeit with a bit of boost tail-off at higher revs. Your gearbox will be the weak link but if you limit boost/torque to sensible numbers it should last for a while. Say 300+ BHP by 300lbft should prove effortlessly flexible. :)

J.

Tidgy,
How much power do you want out of a 2.5l..... circa 600+bhp is possible using todays knowledge and bits that work together, whilst still on pump fuel.

I am not knocking 2l or 2.33l engines, but 2.5's have come a long way over recent times.

yes but that would cost 3/4 grand not very good value for money where as spend that uprating the engine you have and youd be able to go 400/400 very safe engine wise at least then when the box end diffs give up replace them with uprated items and go for 450 which in a classic is like a 550 on a newage but hey its your money!!

name me any 2.5's running that kinda power and have lasted?

i think the biggest difference is the fact the 2.33's are closed deck blocks.

Hi Tidgy,

I guess I should know this since I have a closed deck block...

But.. what is the difference between a closed deck, semi close and open?

Hope it isn't a stupid question...

Thanks

i have a 2.5 in a 98 classic , like tidgy has said, if you want 500bhpand above you want a 2.33 not the 2.5
a standard 2.5 will give about 400ishbhp reliably , from what i have learnt, after 400 the internals are not strong enough to last!!
the torque if used with a reasonable size turbo is very good, i run a vf22, 330bhp and same torq, pulls hard from 2500rpm, spin all wheels in the wet in 1st and 2nd setting off , all down to the torq
thing is with this torq your clutch and gearbox take a pounding, i have the exedy clutch now and it slips under the torq load, next will be a paddle clutch:thumb:
but that will load up the gearbox!!!!, then you need the 6speed (and diff) out of late sti, so the bottomless pit goes on,
my engine runs vf22, hks intake, 3" blitz system(no cat), 440yellow injectors, gems ecu
turbo soon tobe replaced with td05, 16 or18G , sti tmic, and 550pinks, and remap, hoping for around high 300'sbhp ,

Is the 600+ on standard liners ?

No its a cosworth engine :D

standard 2.5 sti block is good for 450/450 with uprated pistons.

2.33's use the EJ22 closed deck block, which are becoming increasingly difficult to obtain.

For a brand new engine set up for a road car,you simply cannot beat the 2.5.

However, the extra strain on the clutch/gearbox may prove costly in the long term...

I run a 2.5 in my classic RA, TD05 18g, power fc, front mount, etc.

The big difference I've found is the low down torque, no need to change down gear at all. I find power does drop off higher up, I don't really need to rev it much beyond 6k though as the power comes in so low down.

Think bhp on mine was about 370 but the torque was touching 400 :D

If you run a similar spec the gearbox won't last 5 minutes, previous owner of my car blew the standard ra box up on the fist mapping session :D Fortunately for me, he fitted a 6 speed from a newage sti which rocks :D

Personally, I think high 300 bhp/torque is more than enough for a road car, any more is just showing off ;)

its to do with the oil feeds

"It's to do with the oil feeds"?

It's actually to do with support for the cylinders - open deck blocks have no supports between the "top" end of the cylinders and the block wall, whereas semi and closed have some supports/ plenty of supports between the two.

The benefits are that the open deck cylinders can "walk" under load (move/distort) which can blow the gasket and/or the cylinders themselves eventually, whereas the supports prevent that. Big power is best made in the strongest i.e. CDB blocks.

Subaru Block aftermarket conversion (not as good as the OEM one, but it shows you what I'm talking about)


The closed deck blocks do also have oil squirters near the crank end which squirt oil at the underside of the pistons.

Thanks fella... makes sense.

Mine is the EJ22t so is the closed deck & squirters... I had guessed 'closed' meant it was a stronger deck, but just wondered on how...

Apologies for the thread hi-jack ;)

cheers for that, never been overly clear myself, but knew it had additional oil things though lol

I've had a 2.5 UK00 Classic for a few years now and after a few early niggles, I love it. Not massive power, 330bhp and 370lbs/ft on a TD05 and all the other usual stuff. Standard gearbox, uprated clutch and IC, standard injectors, EcuTec map. Any more power and it gets very expensive.

It's the way it drives that is so good - loads of smooth power at anything over 2,500rpm. And for a road car it's fookin quick. I can't hold it at WOT for more than five seconds without getting silly. I borrowed a mate's 6.3l Merc AMG recently (lots of nice toys :D) and reckon my car could hold it up to 100mph-ish. Certainly not much in it, but that Merc weighs about 2 tons :eek: After that the Merc was just rocket quick but how fast do you want to go?

If you want a nice lazy-fast car, 2.5 is a good, cheapish option. If you want more than 350/350, then it's going to cost you, and there are other ways of getting there. Also, check out insurance first. Several companies refused me simply because it was a capacity increase. I'm with A-Plan.

Richard.

No-one has mentioned much in the way of pricing.

for a 400bhp 2.5 starting from scratch and built by a highly respected firm then put aside £10,000

scoobyclinic will do one for 9k for 450bhp approx, its called the SC450 ;)

<gulp>

I was thinking (and budgeting) around £3.5k, £1k for turbo, £700 headers, £200 map.

:(

depends on the starting point, you should be able to get your 04sti over 400 and not blow up, although just over is prob about as far as you wanna go

correct :D

There is so much more to budget for, once you get big power, brakes suspension, clutch and gearbox. Ill expect that nearly £15,000 will be my expenditure once all the work is completed

Aye, i've considered this. Getting GT Spec headers, 321H and methanol. But for the cost, for so little gain and the fact i'd be getting closer to trouble, it doesn't seem worth it.

I'm not so hot on what's needed for the (built) engine, so i'm reading up, asking and saving (....well, trying to).

Just not sure i can justify another £5k-£7k on this car. It's dead money. (But i bloody wanna feel like 450/450 feels like :lol1: )

321h?? not bigger or want to just crack 400