How much power is to much

geogan said:
IMO these peak power figures are meaningless for everyday driving. I you are reaching 400BHP that means you are using larger more laggy turbo which only spools up to these peak power figures at stupid RPMs - in the 6000-8000RPM range. Nobody drives normally at over 6000RPM. When you are driving at normal 2-3k RPMs in your 400BHP car you have WAY less than 400BHP available.

My own car has larger turbo which makes up nearly 400Bhp and i have dyno graphs showing power curve - a standard STI turbo reaches its peak power at around 5500RPM and then starts going down again as RPMs get higher. Mine just keeps going up from 5500 all the way to its peak at redline. i.e the extra 140bhp from standard of about 260bhp are in the higher rpm range above 5500 which i 99% never use while driving. And the ironic thing is the other lower end of power graph (because of larger turbo) ends up being LESS bhp than standard so for normal driving i end up with less bhp than a standard STI in the 1000-3000rpm range. I'd be more interested in the torque curve than the bhp curve to gauge overall "fast car" ness...

The only place I actually used the extra power was when I was on track in Mondello because I drove completely "un-normally" and had the RPMs in the 6000-8000RPM range while doing it - of course doing this it used nearly half a tank of E5 for a few laps of track... all the extra mods on car were the only reason it could actually sustain this level of rpm and not blow up engine doing it...
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If this is the case, you havent specd your car well. A 400hp car doesnt have to be and shouldnt be laggy.

The how much power is enough question is kind of a pointless one really, if we are to look at things from the point of view that x amount of bhp is too much then we should question why are we driving performance cars when the speed limit is 60MPH... Like my ould lad always says. :zzzz:
 
as above.


if is laggy the combo of spec is not correct.

comments of reaching peak power at stupid rpms is again a repeat of above. the spec is not correct.

and a 400bhp is absolutely perfectly drivable daily. off boost would feel no
different to standard.
 
davelegacy™ said:
as above.

comments of reaching peak power at stupid rpms is again a repeat of above. the spec is not correct.
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Whatever about lag... obviously bigger turbos are going to be more laggy than smaller standard turbos with faster spin-up times.

By stupid I mean way higher than normal driving RPMs.

I don't think I'm wrong about peak power being at 4500RPM and above for most STIs. I mean any dyno printout I have even seen for any car the peak power is always at or above 4500RPM and either starts going down again or keeps going up.

Nothing to do with spec being not correct. Or are you telling me that by choosing different spec that the peak power can be got at 2000-3000RPM? ie. normal driving ranges. I've never seen a dyno graph like that on a car...

All I'm saying is people say I've got a 400BHP car, yes you might but 95% the time you're driving it you only have less than 200BHP in use, maybe only 100BHP even.

For example this car below. The owner can brag about having 332BHP but that's only around the 4500RPM range. If he's driving at less then 3000RPM he only has a max power of 150BHP...

32557649408126061091017.jpg
 
geogan said:
davelegacy™ said:
as above.

comments of reaching peak power at stupid rpms is again a repeat of above. the spec is not correct.
Click to expand...

Whatever about lag... obviously bigger turbos are going to be more laggy than smaller standard turbos with faster spin-up times.

By stupid I mean way higher than normal driving RPMs.

I don't think I'm wrong about peak power being at 4500RPM and above for most STIs. I mean any dyno printout I have even seen for any car the peak power is always at or above 4500RPM and either starts going down again or keeps going up.

Nothing to do with spec being not correct. Or are you telling me that by choosing different spec that the peak power can be got at 2000-3000RPM? ie. normal driving ranges. I've never seen a dyno graph like that on a car...

All I'm saying is people say I've got a 400BHP car, yes you might but 95% the time you're driving it you only have less than 200BHP in use, maybe only 100BHP even.

For example this car below. The owner can brag about having 332BHP but that's only around the 4500RPM range. If he's driving at less then 3000RPM he only has a max power of 150BHP...

32557649408126061091017.jpg
Click to expand...

No car makes max power low in the rev range...they may make more torque but the won't make max power
 
geogan said:
davelegacy™ said:
as above.

comments of reaching peak power at stupid rpms is again a repeat of above. the spec is not correct.
Click to expand...

Whatever about lag... obviously bigger turbos are going to be more laggy than smaller standard turbos with faster spin-up times.

By stupid I mean way higher than normal driving RPMs.

I don't think I'm wrong about peak power being at 4500RPM and above for most STIs. I mean any dyno printout I have even seen for any car the peak power is always at or above 4500RPM and either starts going down again or keeps going up.

Nothing to do with spec being not correct. Or are you telling me that by choosing different spec that the peak power can be got at 2000-3000RPM? ie. normal driving ranges. I've never seen a dyno graph like that on a car...

All I'm saying is people say I've got a 400BHP car, yes you might but 95% the time you're driving it you only have less than 200BHP in use, maybe only 100BHP even.

For example this car below. The owner can brag about having 332BHP but that's only around the 4500RPM range. If he's driving at less then 3000RPM he only has a max power of 150BHP...

32557649408126061091017.jpg
Click to expand...

So why do you have a 400hp car? Maybe bang a Td04 on it? :roll:
 
So why do you have a 400hp car? Maybe bang a Td04 on it? :roll:
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Because it was in it when i got it. Probably would be better off for normal day to day driving with a smaller turbo - there's a reason Subaru choose these over bigger ones. But anyway big or small the power curve is the same and most people are driving around with a nominal 100BHP most of the time in normal lower revs area.
 
This will always be a devided answers on this.

As stated above,i know few lads that have over 500 and they are daily drivers
 
geogan said:
So why do you have a 400hp car? Maybe bang a Td04 on it? :roll:
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Because it was in it when i got it. Probably would be better off for normal day to day driving with a smaller turbo - there's a reason Subaru choose these over bigger ones. But anyway big or small the power curve is the same and most people are driving around with a nominal 100BHP most of the time in normal lower revs area.
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I was only taking the piss man.
I know exactlythe point you are putting across but doesnt really answer the question of the original poster , but as said already incorrect turbo choice and spec can cause the car not to be as driveable as say a car with 300 or 350 and in most cases those cars will be faster in the real world
 
Thats a load on nonesense Geogan, so if i have a 400 bhp car and i drive it normally, its only a 100bhp car... So in your theory what is a 270bhp sti when driven normally?? 60bhp??
 
if you worried about lag of a bigger turbo consider a twinscroll turbo. lots of options available these days, power comes on a lot earlier. ill be aiming for about 420-440 and leave it at that. Brakes are sorted, suspension will be sorted before that so the bump in power will come last probably early next year at this stage.
 
My Uk turbo classic with it's long gearing sits at about 3000 rpm at 80mph in 5th
Turbo is there but not on full boost till 3400ish with it's current Vf turbo
I think the point above is valid as on my spin to work there is very few places you would be carrying much more speed than this safely
A larger turbo will make it less responsive in the lower revs where most of my driving is done
But yes it's nice to turn the taps on sometimes and use it all and when I gather the funds my classic will see 400 bhp someday
 
A larger turbo will make it less responsive in the lower revs where most of my driving is done
[/quote]

not necessarily as my gt35 is not as laggy geogans hks2835
 
Its a twin scroll HKS turbo that's in his car already Dan :thumbsup:

And sure it really doesn't matter where the power is, the only place this is really relevant is first gear. Once rolling, if your not in the power band, then its time to drop a gear and let the fun begin :multijump:
 
ah right my bad, but yes have heard a few folks giving out about lag on the jap after market turbos, mainly the HKS and Tomei ones, send it over to turbo dynamics for a new billet wheel, that should improve things!
 
Sweetcakes said:
And sure it really doesn't matter where the power is, the only place this is really relevant is first gear. Once rolling, if your not in the power band, then its time to drop a gear and let the fun begin :multijump:
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Exactly....the only cars the really make big power low in the rev range are big engines with super chargers...every car needs to be worked
 
KENC said:
Thats a load on nonesense Geogan, so if i have a 400 bhp car and i drive it normally, its only a 100bhp car... So in your theory what is a 270bhp sti when driven normally?? 60bhp??
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No, what I said is not nonsense at all. You have just confirmed what I was trying to say about how people think they are actually driving around continuously at a constant 400bhp all the time. Did you ever look at a dyno graph of a power curve and understand what you are looking at? Because from that comment it looks entirely like you don't understand it at all... and to answer your question up to about 3000RPM (driven normally) your 270bhp STI has about 150bhp.
 
Altezza-Dan said:
if you worried about lag of a bigger turbo consider a twinscroll turbo. lots of options available these days, power comes on a lot earlier. ill be aiming for about 420-440 and leave it at that. Brakes are sorted, suspension will be sorted before that so the bump in power will come last probably early next year at this stage.
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I wouldn't have much knowledge of different turbo models or which turbo is which or best - i'd leave that up to the mechanical experts like Davelegacy. I know in general though smaller spool up faster and give more boost at lower rpms but max out power earlier because of their size, while larger spool up slower but once going give more power up to higher rpm ranges. I think the one I have is some sort of twinscroll unit. It has a symmetric heat wrapped manifold anyway to get gases out with minimal turbulence for more high end power. I know though from looking at before/after power curves from my car that the power levels at lower rpms were decreased after larger turbo was put in.
 
gonzogicken said:
The future is max torque from zero revs. :049:

http://www.gtplanet.net/forum/showthread.php?p=7635010
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You're dead right there - the electric motor kicks the shite out of any petrol engine in terms of torque curve. Maximum torque across entire band or rpms... ever see the Tesla roadster?... here's what it says on the site - it's called INSTANT TORQUE:

"The AC induction motor and single speed gear box create instant torque from 0 rpm. Up to 295 lbs-ft of torque and 300 horsepower are produced as the car smoothly accelerates from 0 to 60 mph in 3.7 seconds"

ps. love this line "the zero-emissions Roadster can drive 245 miles per charge. It plugs into nearly any outlet, anywhere in the world." - so you plug the car into someone else's house plug, drain enough electricity overnight to charge batteries to drive this thing 245 miles and then leave them to pay the presumably massive electricity bill - love it :multijump:
 
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