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2.0 or 2.5 what's better?

Old 19 February 2009 | 07:42 AM
  #121  
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Originally Posted by TonyBurns
Nick,
still those dont make sense, they look like 2 different rolling roads to start with, the second (JDM) graph shows 267bhp@wheels but only 159bhp/ton, where as the first (2.5) shows 259bhp 162bhp/ton, which straight away shows inconsistancies
On the rhs jdm graph, the faint red line is more in line with the torque delivery of the twin scroll unit, it is a shame i am not at home because if you actually saw what the standard (unmapped) car does, it will shock you a little

Tony
Tony,
Yup, the car weights plugged into each run caused the odd bhp/ton(ne) figures. The UK STi was 1600 Kg, the VF37 JDM is in at a lardy 1700 kg.

I've no idea what the red line mods were. The headline figures are in the order of 360/360, so I guess this was pushing the twin scroll as far as it goes (in line with the SN car development figures & Bob Rawles car).

Rickyas graph is a good starting point and presumably yours will be of the same order? Though I'd love to add a 22% trans. loss to my 4th gear run, It just wouldn't be fair play to do that
Surely someone has a Dyno Dynamics run of an 06> UK STi?
Old 19 February 2009 | 09:50 AM
  #122  
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Originally Posted by dynamix
2.5 is awful I hate mine:
Please someone tell me where this loses to a 2.0L
Great graph. Stunning car, but what is your point??
Your engine is so heavily modded that it bears no absolutely relation to a stock 2.5.
How does this provide an objective contribution to the debate?
Old 19 February 2009 | 10:04 AM
  #123  
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Like this bears no relation to a standard 2 litre but seen as we are posting up graphs would be rude not to post the gobstopper



Banny

Last edited by banny sti; 19 February 2009 at 12:29 PM.
Old 19 February 2009 | 10:07 AM
  #124  
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Originally Posted by Butty
Tony,
Yup, the car weights plugged into each run caused the odd bhp/ton(ne) figures. The UK STi was 1600 Kg, the VF37 JDM is in at a lardy 1700 kg.
I am confused here. Spec C should weigh around 1390 kg with a full tank of fuel (as opposed to 1460 kg for JDM STI).
In any event Spec C will be substantially (100 kg+?) lighter than a UK car. Couple of fat birds in the back seat perhaps??

Also as previously stated Spec C runs a VF36 turbo not a VF37.

Last edited by Blind Side; 19 February 2009 at 10:10 AM.
Old 19 February 2009 | 11:08 AM
  #125  
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I had my JDM STI on the corner weight scales last week. With 1/4 tank of fuel it weighed 1444Kg, to get it up to 1700kg you would need 256Kg of extra weight, thats 3 fairly hefty passengers.

17" version Spec C book weight is 1370kg, JDM STI book weight is 1460Kg, so you can fairly safely say the Spec C with 1/4 tank of fuel is around 1355Kg.
Old 19 February 2009 | 11:11 AM
  #126  
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Originally Posted by Blind Side
I am confused here. Spec C should weigh around 1390 kg with a full tank of fuel (as opposed to 1460 kg for JDM STI).
In any event Spec C will be substantially (100 kg+?) lighter than a UK car. Couple of fat birds in the back seat perhaps??
I'm aware of this additional superiority. Either 1700 Kgs was the actual weight during the run or extra weight has been plugged into the RD calculations afterwards, which bumps up the wheel outputs on road dyno runs - a bit like the high tyre pressure trick.

Also as previously stated Spec C runs a VF36 turbo not a VF37.
Ok - so does that make it a std JDM STi? Perhaps that makes it a more valid comparison?
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Old 19 February 2009 | 11:11 AM
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A 2.5 Type UK is quoted at weighing 1495kg. Spec C at 1390kg and I think (as I can't remember exactly) that a JDM STI is around 1450kg.

EDIT: Just checked an S204 brochure I have and that was quoted at 1445kg.
Old 19 February 2009 | 11:58 AM
  #128  
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Quote:
Originally Posted by Blind Side
I am confused here. Spec C should weigh around 1390 kg with a full tank of fuel (as opposed to 1460 kg for JDM STI).
In any event Spec C will be substantially (100 kg+?) lighter than a UK car. Couple of fat birds in the back seat perhaps??
I'm aware of this additional superiority. Either 1700 Kgs was the actual weight during the run or extra weight has been plugged into the RD calculations afterwards, which bumps up the wheel outputs on road dyno runs - a bit like the high tyre pressure trick.

Also as previously stated Spec C runs a VF36 turbo not a VF37.
Ok - so does that make it a std JDM STi? Perhaps that makes it a more valid comparison?


Nick
Fair enough Nick, although you did say your graph comparison involved a Spec C. Thanks for the info anyway.
Old 19 February 2009 | 12:27 PM
  #129  
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Originally Posted by dynamix
2.5 is awful I hate mine:



Please someone tell me where this loses to a 2.0L
well as you asked and about no particular 2.0, i would say ta, ss and totb
Old 19 February 2009 | 12:49 PM
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Originally Posted by Blind Side
Great graph. Stunning car, but what is your point??
Your engine is so heavily modded that it bears no absolutely relation to a stock 2.5.
How does this provide an objective contribution to the debate?
Not really that modified.

Std heads
Std cams
Std ECU
Std Maf
Std gearbox
Std diff
.......

Sure the engine is forged but the 2.0L is forged too. It has the benefit of a great turbo to make use of the strength in the block that area 52 built but you are talking about the 2.0 vs 2.5 argument and using the gobstopper as an example of a great 2.0 - that is hardly a std block or engine is it?

All other mods that have gone on are for safety or out of necessity for the power, ie clutch or fmic

When you have a wall of torque why would you want to rev the nuts of something to 8000 rpm ?
Old 19 February 2009 | 02:03 PM
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Originally Posted by banny sti
Like this bears no relation to a standard 2 litre but seen as we are posting up graphs would be rude not to post the gobstopper



Banny
Absolutely amazing though those figures are from a 2litre, am I reading that correctly in saying that it produces 100ft lbs torque at 4000rpm?!?!?

For a road car?!?! No thanks!
Old 19 February 2009 | 02:42 PM
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Originally Posted by dynamix
2.5 is awful I hate mine:



Please someone tell me where this loses to a 2.0L



Old 19 February 2009 | 03:18 PM
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Originally Posted by dynamix
When you have a wall of torque why would you want to rev the nuts of something to 8000 rpm ?
Because some people want that experience, others do not. It all comes down to personal preference and driving style.

A high revving NA engine can give a wonderful and rewarding driving experience that no FI engine could ever reproduce, and vice versa.
Old 19 February 2009 | 04:28 PM
  #134  
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Just thought I'd put my two penneth worth in. Now I've got no idea what a lot of you were talking about with this map and that mod etc, and to be honest only got down half way of the second page before I stopped reading. However, here's my opinion.

I had the 2004 STi UK spec, absolutely standard, and loved the way it revved, and the way the turbo kicked in, but unfortunatley it had to go last year. Happily though I've just ordered and 06 STi 2.5 with PPP. To me I didn't notice that it had lost any of it willingness to rev, plus it had more torque and so pulled harder. So to me it had the characteristics I loved about my 2004 STi, but with more torque, so to me is a winner.

I would like to add though that I only took it out for half an hours test so will have a better opinion after a couple of weeks or so :-)

Incidently, I did find that the steering was a bit lighter than my old Scooby, I prefered it a bit heavier. Is this really the case or just that I've ben driving a Fez ST around for a while which handles like a go-kart?, or is it the Toyo tyres?
Old 19 February 2009 | 05:28 PM
  #135  
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i managed 390lbft from my 16g 2.5

i suspect it may have done a bit more then that if cylinder number 4 had more then 10psi compression lmfao!

this run was done with a buggered ringland



2.5 FTW!

cant wait to get cylinder number 4 working again ha ha!

Last edited by StickyMicky; 19 February 2009 at 05:33 PM.
Old 19 February 2009 | 06:43 PM
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Originally Posted by StickyMicky
this run was done with a buggered ringland
So are you promoting the tunability of a 2.5, or showing its weakness

What boost levels & charge temp did that then?
Old 19 February 2009 | 08:34 PM
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The 2.5 isn't weak, its stock pistons aren't brilliant, but replace them with a set of forged pistons and it'll be just as strong as the Newage 2 litre engines.

Last edited by MartynJ; 19 February 2009 at 08:36 PM.
Old 19 February 2009 | 08:43 PM
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Originally Posted by MartynJ
The 2.5 isn't weak, its stock pistons aren't brilliant, but replace them with a set of forged pistons and it'll be just as strong as the Newage 2 litre engines.
Words of wisdom
Old 19 February 2009 | 10:21 PM
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true pistons are the weak link,one piston has failed on my 2008sti
Old 20 February 2009 | 12:55 AM
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Originally Posted by stuart2008sti
true pistons are the weak link,one piston has failed on my 2008sti
One of the Surrey lots 08 sti just did the same, seams to be a fault
Old 20 February 2009 | 08:43 AM
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Originally Posted by stuart2008sti
true pistons are the weak link,one piston has failed on my 2008sti
Number 3 by any chance?
Old 20 February 2009 | 09:56 AM
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Originally Posted by stuart2008sti
true pistons are the weak link,one piston has failed on my 2008sti
Wasn't the recent re-flash for the 2008 STI meant to reduce the chances of that failure?
Old 20 February 2009 | 10:03 AM
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Think the damaged occured before the reflash,
Old 20 February 2009 | 10:13 AM
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I got mine re-flashed last week during it's 10k service, so hopefully I'll have no future issues.
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