Best cost effective way to 500bhp
09 January 2012, 06:52 PM
#61
A full 2.5" decat system with a open mouth DP would be fine at 500. It would give you more midrange grunt and help with spool. I currently run a TSL gas flowed 2.5" DP at 443hp. If you want more top end then a 3" system would be good.
I think its all about the setup and how the car performs, but its also nice to see big numbers. However numbers are just numbers. For example back in the days i sat in a Type R with 2.1 stroker, 18g, STI 6 box, Simtek etc, it had proper parts with full supporting mods and not making big numbers, however this thing was ruthless! Putting big cars to shame such as Lambo's, Porsches, big powered Evo's & so on. It had amazing spool with dirty top end.
This just goes to show its not always about ***** waving numbers.
I think its all about the setup and how the car performs, but its also nice to see big numbers. However numbers are just numbers. For example back in the days i sat in a Type R with 2.1 stroker, 18g, STI 6 box, Simtek etc, it had proper parts with full supporting mods and not making big numbers, however this thing was ruthless! Putting big cars to shame such as Lambo's, Porsches, big powered Evo's & so on. It had amazing spool with dirty top end.
This just goes to show its not always about ***** waving numbers.
I currently have a prodrive downpipe from a WR1, the rest of the exhaust is standard 2006 STI, you reckon this could work for 450 / 450?
09 January 2012, 07:06 PM
#62
OEM style (wastegate area closed off)
Divorced (sepearte venturi exit for wastegate gasses)
Open
As you can see, the OEM style is restrictive. The open style is what most people opt for as it's considered freer flowing, and the full opening ensures the w/g penny valve can defo open fully.
Last edited by joz8968; 09 January 2012 at 08:14 PM.
09 January 2012, 09:06 PM
#65
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When I get the dough to try a 2.35 then I'll tell you what I make of that, but I would say that having had the 2.5, I'd never go back to the 2.0, not even the twin scroll!
Horses for courses I guess
09 January 2012, 09:29 PM
#66
OEM style (wastegate area closed off)
Divorced (sepearte venturi exit for wastegate gasses)
Open
As you can see, the OEM style is restrictive. The open style is what most people opt for as it's considered freer flowing, and the full opening ensures the w/g penny valve can defo open fully.
Divorced (sepearte venturi exit for wastegate gasses)
Open
As you can see, the OEM style is restrictive. The open style is what most people opt for as it's considered freer flowing, and the full opening ensures the w/g penny valve can defo open fully.
I believe the prodrive downpipes are a "divorced" design, is that right?
09 January 2012, 10:54 PM
#68
Scooby Regular
The 2ltr vs 2.5ltr is a debate that will carry on....
NS04,
2.5's are great when they hold together..... unfortunately when you actually start driving it proper that is far from being a cert. Many of us have been there before and I can quite catagorically state I would never use a 2.5 as a basis again for tuning... period.
They're a badly designed block, no matter how you look at it. You can't polish a turd.
Always two sides to every story and every opinion.
Kas Spec C,
Not all 2.5's are the same, so don't judge them all by one experience. If you had ever driven my old Spec C 2.5ltr, I guarantee you wouldn't of thought it was not aggressive.
NS04,
2.5's are great when they hold together..... unfortunately when you actually start driving it proper
that is far from being a cert. Many of us have been there before and I can quite catagorically state I would never use a 2.5 as a basis again for tuning... period.They're a badly designed block, no matter how you look at it. You can't polish a turd.
Always two sides to every story and every opinion.
Kas Spec C,
Not all 2.5's are the same, so don't judge them all by one experience. If you had ever driven my old Spec C 2.5ltr, I guarantee you wouldn't of thought it was not aggressive.
09 January 2012, 11:12 PM
#69
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The 2ltr vs 2.5ltr is a debate that will carry on....
NS04,
2.5's are great when they hold together..... unfortunately when you actually start driving it proper that is far from being a cert. Many of us have been there before and I can quite catagorically state I would never use a 2.5 as a basis again for tuning... period.
They're a badly designed block, no matter how you look at it. You can't polish a turd.
Always two sides to every story and every opinion.
Kas Spec C,
Not all 2.5's are the same, so don't judge them all by one experience. If you had ever driven my old Spec C 2.5ltr, I guarantee you wouldn't of thought it was not aggressive.
NS04,
2.5's are great when they hold together..... unfortunately when you actually start driving it proper
that is far from being a cert. Many of us have been there before and I can quite catagorically state I would never use a 2.5 as a basis again for tuning... period.They're a badly designed block, no matter how you look at it. You can't polish a turd.
Always two sides to every story and every opinion.
Kas Spec C,
Not all 2.5's are the same, so don't judge them all by one experience. If you had ever driven my old Spec C 2.5ltr, I guarantee you wouldn't of thought it was not aggressive.
I'm painfully aware that I have no where near the fastest car (sorry, biggest *****)
Nor is it the most robust engine (no one has ever argued that with the 2.5 block) but it's irrelevant on the road in any case, you'll never drive it hard enough to break a properly built one unless A) you're being a total dingbat b) you've had silly boost mapped in, with the SC46 it needs only around 1.7bar to return 460bhp c) Both! If you want more than the mid 400s and you want to cane it to within an inch of its life you go for a 2.0, 2.1 or 2.35. It's about making the right choice when you specify the car. If you want a road car with 450/450 and you want the best spool and torque, you go for a 2.5. If you want a track car or you have aspirations above the mid 400s, you'd look at a smaller capacity. As for polishing a turd with that block.... isn't that what Bob's currently having a good go at!?! And lets not be silly, a 450/450 scooby (not just mine - any scooby at that power level) is a VERY fast car. As I said, it made a porka 997 turbo owner blush and if you can argue that that is a slow car, you're driving something like the gobstopper.... and all power to you!
People keep banging on about them not being suitable for really big bhp builds (e.g. 500s plus) etc... but NO ONE is saying they are. But if you want a road car in the mid 400s it's a very effective solution.
The smaller displacements tend to feel more savage because of the way the power is delivered: with the 2.5s there is more grunt low down, compared to the more "wait for it, wait for it, BANG" which is great fun, but not optimal for road driving (what many want in the broadest range of power and torque). That said, I've not be found wanting for savagery in mine - the way it rips though (even the UK hawkeye's long ratios) is very impressive and it would take a very jaded person to not at least raise an eyebrow.
Like I said, it's very much a case of horses for courses and getting the right starting point given the desired character and use of the car.
People seem to want to create conflict where there is none! That's SN for ya!
Last edited by New_scooby_04; 10 January 2012 at 12:00 AM.
09 January 2012, 11:31 PM
#70
The 2ltr vs 2.5ltr is a debate that will carry on....
NS04,
2.5's are great when they hold together..... unfortunately when you actually start driving it proper that is far from being a cert. Many of us have been there before and I can quite catagorically state I would never use a 2.5 as a basis again for tuning... period.
They're a badly designed block, no matter how you look at it. You can't polish a turd.
Always two sides to every story and every opinion.
Kas Spec C,
Not all 2.5's are the same, so don't judge them all by one experience. If you had ever driven my old Spec C 2.5ltr, I guarantee you wouldn't of thought it was not aggressive.
NS04,
2.5's are great when they hold together..... unfortunately when you actually start driving it proper
that is far from being a cert. Many of us have been there before and I can quite catagorically state I would never use a 2.5 as a basis again for tuning... period.They're a badly designed block, no matter how you look at it. You can't polish a turd.
Always two sides to every story and every opinion.
Kas Spec C,
Not all 2.5's are the same, so don't judge them all by one experience. If you had ever driven my old Spec C 2.5ltr, I guarantee you wouldn't of thought it was not aggressive.
I have sat in numerous cars with 2.5's and found them to be very lean when delivering the power. Not as brutal compared to other displacements.
The only time I was chuffed is when i drove a STi 8 with a pegged 2.5, JDM avcs that had race cams and a 35r turbo. Guess headwork makes a huge difference.
My experience is based on owning yellow pages of Subaru's with different types of setup's. Also i know many other close friends who have serious Subz with similar setup's.
2.5 is like marmite, you either love it or hate it. High powered 2.5's come with a bag full of issues.
10 January 2012, 12:06 AM
#71
Very true. Not all are the same.
I have sat in numerous cars with 2.5's and found them to be very lean when delivering the power. Not as brutal compared to other displacements.
The only time I was chuffed is when i drove a STi 8 with a pegged 2.5, JDM avcs that had race cams and a 35r turbo. Guess headwork makes a huge difference.
My experience is based on owning yellow pages of Subaru's with different types of setup's. Also i know many other close friends who have serious Subz with similar setup's.
2.5 is like marmite, you either love it or hate it. High powered 2.5's come with a bag full of issues.
I have sat in numerous cars with 2.5's and found them to be very lean when delivering the power. Not as brutal compared to other displacements.
The only time I was chuffed is when i drove a STi 8 with a pegged 2.5, JDM avcs that had race cams and a 35r turbo. Guess headwork makes a huge difference.
My experience is based on owning yellow pages of Subaru's with different types of setup's. Also i know many other close friends who have serious Subz with similar setup's.
2.5 is like marmite, you either love it or hate it. High powered 2.5's come with a bag full of issues.
Oh dear , I'm having a 2.5 build avc,s as we speak ! Will I be having problems ?
10 January 2012, 01:11 AM
#72
If you like to thrash your car then 2.5 is not a good idea.
10 January 2012, 01:34 AM
#73
Upto 500 it will be safe if the block is pegged, along with a decent safe tune. Common failures are headgaskets and the block. It all depends on how you drive it. 2.5 also consumes alot of oil and they dont like to be over reved. 14mm headstud conversion is a good idea if you intend on running high boost.
If you like to thrash your car then 2.5 is not a good idea.
If you like to thrash your car then 2.5 is not a good idea.
14mm apr stud done , block has been pinned ! Running twisted rcm with billet gt30 gtx
maz
10 January 2012, 07:35 AM
#74
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having my engine built for my classic sti 8 jdm cdb sti ver4 heads was wondering weather to go forged or not. ill be happy with 400 tbo and what turbo would anyone recomend want pretty good spool try and keep lag down to a minimal was thinking sc46 but what would it perform like and that spec without forging will it make 400
10 January 2012, 01:23 PM
#79
Scooby Regular
You've gotta love the ***** waving!
I'm painfully aware that I have no where near the fastest car (sorry, biggest *****) Nor is it the most robust engine (no one has ever argued that with the 2.5 block) but it's irrelevant on the road in any case, you'll never drive it hard enough to break a properly built one unless A) you're being a total dingbat b) you've had silly boost mapped in, with the SC46 it needs only around 1.7bar to return 460bhp c) Both! If you want more than the mid 400s and you want to cane it to within an inch of its life you go for a 2.0, 2.1 or 2.35. It's about making the right choice when you specify the car. If you want a road car with 450/450 and you want the best spool and torque, you go for a 2.5. If you want a track car or you have aspirations above the mid 400s, you'd look at a smaller capacity. As for polishing a turd with that block.... isn't that what Bob's currently having a good go at!?!
And lets not be silly, a 450/450 scooby (not just mine - any scooby at that power level) is a VERY fast car. As I said, it made a porka 997 turbo owner blush and if you can argue that that is a slow car, you're driving something like the gobstopper.... and all power to you!
People keep banging on about them not being suitable for really big bhp builds (e.g. 500s plus) etc... but NO ONE is saying they are. But if you want a road car in the mid 400s it's a very effective solution.
The smaller displacements tend to feel more savage because of the way the power is delivered: with the 2.5s there is more grunt low down, compared to the more "wait for it, wait for it, BANG" which is great fun, but not optimal for road driving (what many want in the broadest range of power and torque). That said, I've not be found wanting for savagery in mine - the way it rips though (even the UK hawkeye's long ratios) is very impressive and it would take a very jaded person to not at least raise an eyebrow.
Like I said, it's very much a case of horses for courses and getting the right starting point given the desired character and use of the car.
People seem to want to create conflict where there is none! That's SN for ya!
I'm painfully aware that I have no where near the fastest car (sorry, biggest *****)
Nor is it the most robust engine (no one has ever argued that with the 2.5 block) but it's irrelevant on the road in any case, you'll never drive it hard enough to break a properly built one unless A) you're being a total dingbat b) you've had silly boost mapped in, with the SC46 it needs only around 1.7bar to return 460bhp c) Both! If you want more than the mid 400s and you want to cane it to within an inch of its life you go for a 2.0, 2.1 or 2.35. It's about making the right choice when you specify the car. If you want a road car with 450/450 and you want the best spool and torque, you go for a 2.5. If you want a track car or you have aspirations above the mid 400s, you'd look at a smaller capacity. As for polishing a turd with that block.... isn't that what Bob's currently having a good go at!?! And lets not be silly, a 450/450 scooby (not just mine - any scooby at that power level) is a VERY fast car. As I said, it made a porka 997 turbo owner blush and if you can argue that that is a slow car, you're driving something like the gobstopper.... and all power to you!
People keep banging on about them not being suitable for really big bhp builds (e.g. 500s plus) etc... but NO ONE is saying they are. But if you want a road car in the mid 400s it's a very effective solution.
The smaller displacements tend to feel more savage because of the way the power is delivered: with the 2.5s there is more grunt low down, compared to the more "wait for it, wait for it, BANG" which is great fun, but not optimal for road driving (what many want in the broadest range of power and torque). That said, I've not be found wanting for savagery in mine - the way it rips though (even the UK hawkeye's long ratios) is very impressive and it would take a very jaded person to not at least raise an eyebrow.
Like I said, it's very much a case of horses for courses and getting the right starting point given the desired character and use of the car.
People seem to want to create conflict where there is none! That's SN for ya!
I'm not saying yours will rip it's **** out, but it has a higher chance of happening with the 2.5 than it does say a 2ltr at this similar level imo.
Too many people are getting sold 450bhp type conversions with the expectations that it will require no more maintenance etc than a standard 280bhp Scoob. It's just not true. This is a general comment and not aimed at you.
I know 2.5's that have split liners at boost lower than 1.7bar and only used on the road. I know 2.5's that have blown HG's at boost lower than 1.7bar. These issues have and continue to happen with standard cars, let alone tuned ones.
I also know a lot of people that have 2.5's on two maps... one low boost (say 380bhp) and one on high boost for the 460bhp. They drive mostly on the low boost setting.... I wonder why.
You made your decision for your own reasons, but don't expect everyone else to have the same views.
This has nothing to do with conflict at all, it's about other people giving their views and opinions...... even if they differ from yours!
Yes... the 2.5's have great driveability and torque. This comes at a price imo, that I personally would not be willing to accept again. The older you get the more you want zero stress, regardless of how much cash you can keep throwing at a car.
As you have taken the time to quote Bob's car (and heaven forbid anyone that has a different opinion to Bob - tongue in cheek towards you mentioning it), you will also realise that he has had a lot of prep work done to that block....... but even that does not mean it won't F up.
10 January 2012, 06:56 PM
#83
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Never driven a 2.5 but from what everyone's saying, it sounds like it drives like a turbo diesel.
Kas isn't that guy in the video a bit low on power if he's running a GT40R?? Probably running on low boost to save his 2.5, but it picks up speed mad though. Must be savage on the road.
Kas isn't that guy in the video a bit low on power if he's running a GT40R?? Probably running on low boost to save his 2.5, but it picks up speed mad though. Must be savage on the road.
10 January 2012, 09:08 PM
#87
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You really need to take a deep breath and stop getting so defensive when people give differing views to your own and the path you have chosen. Whilst I appreciate you have spent an amount of money on your engine, and whilst I understand that you have done your research.... I personally would never buy another 2.5 block again for modding.
My point was exactly that: there is more than one route to take and the route you go down depends on the application of the car and what you want out of it. The important thing is that you do it from an informed point of view and know what you're getting at the end of it
To be honest, I think people who drive on a low boost map on a 2.5 for normal driving find that such is the flexibility of the car, you just don't need it on the high boost setting to make progress either that or they're trying to save pennies on the petrol
. Lots of people have twin maps on 2.0 litre cars too. Personally, I don't have a low boost map, I just use my right foot! I know that Bob has had some prep work done to the block. The reason I bought it up was that you called the 2.5 block a turd and said it couldn't be polished. Well, with the whole cryo treatment preparation, surely that's what he'd be doing by your reasoning, or he would have just thrown the block away and got a 2.35
