2.0 or 2.5 help for 550bhp
21 October 2012, 01:02 AM
#33
It had very low torque numbers for the power, so although top end figure is impressive, it's not really getting great performance or pushing the engine hard. I wouldnt use that as a reference to thinking a stock engine is good at 520BHP, it may be OK if you slug the torque like that, but it would be slow by comparison to a properly built engine with a good torque band.
21 October 2012, 01:09 AM
#34
It had very low torque numbers for the power, so although top end figure is impressive, it's not really getting great performance or pushing the engine hard. I wouldnt use that as a reference to thinking a stock engine is good at 520BHP, it may be OK if you slug the torque like that, but it would be slow by comparison to a properly built engine with
a good torque band.
a good torque band.
21 October 2012, 01:33 AM
#35
Not a lot more considering you already had the heads off.
Thats not the point i was making though, it was more a comment on the real world performance a limited torque engine would provide. Was the torque limited on purpose to save load on the engine, or was that the nature of your turbo?
Thats not the point i was making though, it was more a comment on the real world performance a limited torque engine would provide. Was the torque limited on purpose to save load on the engine, or was that the nature of your turbo?
21 October 2012, 02:35 PM
#36
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Right im after a little bit of info and help lol
Im just building my v7 sti jdm impreza to 550bhp and want to know what bottom end is the best? The 2.0 or 2.5?
My mods are gt30/40 turbo rotated kit external wastegate, 1000cc injectors, simtek ecu, external fuel pumps etc.
I was going to go with my 2.0 and have it fully forged but have been offered a 2.5 fully built for a really good price.
I just want to know what you guys think?
Thanks in advance.
Im just building my v7 sti jdm impreza to 550bhp and want to know what bottom end is the best? The 2.0 or 2.5?
My mods are gt30/40 turbo rotated kit external wastegate, 1000cc injectors, simtek ecu, external fuel pumps etc.
I was going to go with my 2.0 and have it fully forged but have been offered a 2.5 fully built for a really good price.
I just want to know what you guys think?
Thanks in advance.
Forged 2.5 a great engine for the road, but most (if not all) tuners will tell you to stick to the mid 400s with the 2.5 block unless you get it pinned; and they will still be equivocal about whether that will be successful.
If you MUST have over 500 then 2.1 would be the most cost effective way, but obviously it won't spool as well as a 2.5 when fitted with a big blower! 2.0 block will go there, but again, it will be laggy compared to a bigger capacity engine.
2.35 would give you the best of both worlds, but is even more expensive.
For a road car, I'd go with a forged 2.5 with an SC46 billet every time. mid-late 400s, spools like a std car (if not better) torque everywhere, just the right amount of power before things get a bit hairy!
21 October 2012, 02:46 PM
#37
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It had very low torque numbers for the power, so although top end figure is impressive, it's not really getting great performance or pushing the engine hard. I wouldnt use that as a reference to thinking a stock engine is good at 520BHP, it may be OK if you slug the torque like that, but it would be slow by comparison to a properly built engine with a good torque band.
21 October 2012, 02:50 PM
#38
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2.0 block will go there, but again, it will be laggy compared to a bigger capacity engine.
For a road car, I'd go with a forged 2.5 with an SC46 billet every time. mid-late 400s, spools like a std car (if not better) torque everywhere, just the right amount of power before things get a bit hairy!
For a road car, I'd go with a forged 2.5 with an SC46 billet every time. mid-late 400s, spools like a std car (if not better) torque everywhere, just the right amount of power before things get a bit hairy!
I know of a 2.1 set-up on here that would knock the **** out of nearly most 450bhp 2.5 set-ups, but that's another story and I don't like blowing smoke up that owners ****!
21 October 2012, 04:34 PM
#39
Now, whilst I wouldn't argue with what you have said, I would be really interested and I'm sure others would, to see how well a car like yours accelerates against something like mine. I suspect the difference won't be that much..... certainly not for the costs involved.
I know of a 2.1 set-up on here that would knock the **** out of nearly most 450bhp 2.5 set-ups, but that's another story and I don't like blowing smoke up that owners ****!
I know of a 2.1 set-up on here that would knock the **** out of nearly most 450bhp 2.5 set-ups, but that's another story and I don't like blowing smoke up that owners ****!
In the meantime he graphs you know of would be a good place to start as I very much doubt the above would ever happen
21 October 2012, 04:42 PM
#40
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Bollocks to "built"...... "standard" is the new modified!! 
We don't need this level of comparison..... just get a few cars across the range entering next years MLR 30-130 Marham event. No dynos and no bull****..... you don't even need any skill, so even I should do alright! lol
I'm up for it win, lose or blow-up!
We don't need this level of comparison..... just get a few cars across the range entering next years MLR 30-130 Marham event. No dynos and no bull****..... you don't even need any skill, so even I should do alright! lol
I'm up for it win, lose or blow-up!
21 October 2012, 04:53 PM
#41
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You have to remember that what I've paid is a sum to make the 2.5 bulletproof at my level. I could have done it cheaper, with a little less "reassurance" IYSWIM.
21 October 2012, 05:22 PM
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The 2.1 route would be the cheapest option for that power level. I have been in a 550+ bhp 2.5 and it was awesome with over 550ft/lb of torque. It drove like any other road car at low speeds and when the loud peddle was pressed it was mental with zero lag.
That 2.5 block had some serious money and engineering on it to get it to that level. It was the 2010 block which has thicker liners and was converted to CDB and cryogenicly treated.
Read Bob Rawles project thread for more info.
That 2.5 block had some serious money and engineering on it to get it to that level. It was the 2010 block which has thicker liners and was converted to CDB and cryogenicly treated.
Read Bob Rawles project thread for more info.
21 October 2012, 05:33 PM
#44
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BTW, how many miles have you done now?
21 October 2012, 06:14 PM
#45
LOL at £20k
I wonder if the likes of banny sti would dare add up what it costs and tell us the total bill to go 550bhp and above.
Daz davies is probably the man that has done it the cheapest via the 2.5 route,and he did most of it DIY and still spent a packet to get the sort of numbers your after, and the fact he is now driving a 2.0l jdm newage with circa 450 bhp speaks volumes.
I dipped a toe in the water and it's way too hot for my liking, especially because as said above, 450bhp is relatively easy these days and very cheap by comparison, also in a road car how often do you and can you use the extra umph per £££.
Ultimately the law of diminishing returns applies after 450/480 bhp, both financally and speed wise, after all we are talking fractions of seconds in 0/60 and 0/100 times per tens of thousands of pounds, and then there is the reliability factor, it's only a matter of time before something goes pop usually with catastrophic results.
I wonder if the likes of banny sti would dare add up what it costs and tell us the total bill to go 550bhp and above.
Daz davies is probably the man that has done it the cheapest via the 2.5 route,and he did most of it DIY and still spent a packet to get the sort of numbers your after, and the fact he is now driving a 2.0l jdm newage with circa 450 bhp speaks volumes.
I dipped a toe in the water and it's way too hot for my liking, especially because as said above, 450bhp is relatively easy these days and very cheap by comparison, also in a road car how often do you and can you use the extra umph per £££.
Ultimately the law of diminishing returns applies after 450/480 bhp, both financally and speed wise, after all we are talking fractions of seconds in 0/60 and 0/100 times per tens of thousands of pounds, and then there is the reliability factor, it's only a matter of time before something goes pop usually with catastrophic results.
21 October 2012, 06:22 PM
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Thanks, I had a look at Bob's thread which I hadn't read before and it sounds a great car, but what struck me is the likely cost of it all, including what sounds like a very special engine build. That is great for Bob as he has contacts, it develops and promotes his tuning and I bet he also really enjoyed it. I wonder though what the overall bill would be for a customer and the value for money as well as the loss when selling the car (unless it is a known car like Bob's) must be quite painful. I could easily see the bill being £20k for all the mods, plus the cost of a nice 3 year old car, you're in 3 year old GTR territory which with a tune only can dip into the high 10s on the quarter, and still on stock turbos can be in the very low 10s. I know I'm biased, but how does this argument stack up to you guys? Do you think my £20k estimate for a really top notch full build with all the ancillaries, brakes, suspension, tuning etc is an overestimate? When you look at what a lot of people spend and then sell for it is scary.
but i think 20k would be a realistic guess and maybe even a tad conservative. You are correct in saying your into GTR money but some peeps get the joy out of modding rather than buy a factory fast car. Besides from what i have read here i have no doubt most would buy the GTR then start modding that your all junkies.What i like about Bobs car and respect is not sticking to the tried and tested route. Taking something over looked by the tuning community because of weaknesses and finding ways to develop it and get big reliable power. Thats real tuning imho
21 October 2012, 07:53 PM
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21 October 2012, 08:00 PM
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1740kg, but I'm not trying to turn this into a GTR love thread. Don't calculate acceleration based on power to weight though - aerodynamics, lag, power band, dual clutch gearbox, launch and traction all make it use its power well. When standard at similar power to the final spec of my Subaru, it accelerated better through the gears, despite 500kg more weight.
21 October 2012, 08:10 PM
#54
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21 October 2012, 08:11 PM
#55
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I was about to say "what you on about, I've never done Marham before".... then I realised what you were referring to.
21 October 2012, 11:48 PM
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In David's words, my engine is "over-engineered" for my level of tune.About 11k miles now. Not needed a single top up of oil, quiet as a mouse (for a forged engine) and the only thing that's given me any grief is a dodgy lamda sensor (How much are they?!?!?!) and one of the braided lines worked its way a bit loose and needed a tighten (is that gasoline I smell, lol).
Now I've jinxed it - expect a "my engine died" thread tomorrow
21 October 2012, 11:56 PM
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Thanks, I had a look at Bob's thread which I hadn't read before and it sounds a great car, but what struck me is the likely cost of it all, including what sounds like a very special engine build. That is great for Bob as he has contacts, it develops and promotes his tuning and I bet he also really enjoyed it. I wonder though what the overall bill would be for a customer and the value for money as well as the loss when selling the car (unless it is a known car like Bob's) must be quite painful. I could easily see the bill being £20k for all the mods, plus the cost of a nice 3 year old car, you're in 3 year old GTR territory which with a tune only can dip into the high 10s on the quarter, and still on stock turbos can be in the very low 10s. I know I'm biased, but how does this argument stack up to you guys? Do you think my £20k estimate for a really top notch full build with all the ancillaries, brakes, suspension, tuning etc is an overestimate? When you look at what a lot of people spend and then sell for it is scary.
Reliable 550+ in a scoob with the appropriate supporting mods would be 20k + the donor car all day long I reckon!
My car (470/480) is about 22ks worth all in and the base car was a very fit Hawk STi PPP (so less than he price of a new STi) I can just about rationalise that!
After this level the costs mount up significantly and there seems to be a law of diminishing returns operating. TBH the only economical way of doing it is to wait until some poor soul sells a good modified example, where they have absorbed the build costs!
Unless I suddenly develop more money than sense, If I wanted to go higher than my current level, I would
A) Buy one that'd already been done by a reputable company
B) Go down the GTR route.
Last edited by New_scooby_04; 22 October 2012 at 12:00 AM.
21 October 2012, 11:57 PM
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Well I use the term bullet proof loosely! In David's words, my engine is "over-engineered" for my level of tune.
About 11k miles now. Not needed a single top up of oil, quiet as a mouse (for a forged engine) and the only thing that's given me any grief is a dodgy lamda sensor (How much are they?!?!?!) and one of the braided lines worked its way a bit loose and needed a tighten (is that gasoline I smell, lol).
Now I've jinxed it - expect a "my engine died" thread tomorrow
In David's words, my engine is "over-engineered" for my level of tune.About 11k miles now. Not needed a single top up of oil, quiet as a mouse (for a forged engine) and the only thing that's given me any grief is a dodgy lamda sensor (How much are they?!?!?!) and one of the braided lines worked its way a bit loose and needed a tighten (is that gasoline I smell, lol).
Now I've jinxed it - expect a "my engine died" thread tomorrow