Power Outputs, Claimed vs Reality ?
Discussion
Was reading the other day how some cars tend to deliver more power than they are supposed to and some
deliver less, the one with more was any 130 bhp VAG engine which tends to be nearer 140 and the ones down on power being M3 engines which never seem to quite make the quoted bhp.
Also, tuning seems to create massive power claims which tend to be on the optimistic side, especially given the vast variance in dyno outputs, interested in your findings with regards to outputs of specific cars and whether ti was bang on, more or less than expected or quoted.
I spent about £700 on "tuning" an 8 valve Golf GTI, MK2, Superchip, Magnex Exhaust and an indiction kit and it made a princely 4.5 extra bhp over standard 116.5 versus 112, that may have been down to it being on good form as well, all the bolts on made more noise, but more power, hmm, not so sure !
deliver less, the one with more was any 130 bhp VAG engine which tends to be nearer 140 and the ones down on power being M3 engines which never seem to quite make the quoted bhp.
Also, tuning seems to create massive power claims which tend to be on the optimistic side, especially given the vast variance in dyno outputs, interested in your findings with regards to outputs of specific cars and whether ti was bang on, more or less than expected or quoted.
I spent about £700 on "tuning" an 8 valve Golf GTI, MK2, Superchip, Magnex Exhaust and an indiction kit and it made a princely 4.5 extra bhp over standard 116.5 versus 112, that may have been down to it being on good form as well, all the bolts on made more noise, but more power, hmm, not so sure !
J4CKO said:
Was reading the other day how some cars tend to deliver more power than they are supposed to and some
deliver less, the one with more was any 130 bhp VAG engine which tends to be nearer 140 and the ones down on power being M3 engines which never seem to quite make the quoted bhp.
Also, tuning seems to create massive power claims which tend to be on the optimistic side, especially given the vast variance in dyno outputs, interested in your findings with regards to outputs of specific cars and whether ti was bang on, more or less than expected or quoted.
I spent about £700 on "tuning" an 8 valve Golf GTI, MK2, Superchip, Magnex Exhaust and an indiction kit and it made a princely 4.5 extra bhp over standard 116.5 versus 112, that may have been down to it being on good form as well, all the bolts on made more noise, but more power, hmm, not so sure !
I don't know the answer, but why would any manufacturer under-quote the horsepower? deliver less, the one with more was any 130 bhp VAG engine which tends to be nearer 140 and the ones down on power being M3 engines which never seem to quite make the quoted bhp.
Also, tuning seems to create massive power claims which tend to be on the optimistic side, especially given the vast variance in dyno outputs, interested in your findings with regards to outputs of specific cars and whether ti was bang on, more or less than expected or quoted.
I spent about £700 on "tuning" an 8 valve Golf GTI, MK2, Superchip, Magnex Exhaust and an indiction kit and it made a princely 4.5 extra bhp over standard 116.5 versus 112, that may have been down to it being on good form as well, all the bolts on made more noise, but more power, hmm, not so sure !
Presumably you've not had the engine rebuilt recently, so that bhp increase will be over the standard quoted figure minus 20+ years of wear. Then factor in the margin of error present in the rolling road and the assumptions it has to make to calculate bhp at the flywheel from bhp measured at the wheels.
If you didn't take a rolling road measurement before making the upgrades, then you can only really guess at the difference it's made. What really matters is whether or not you feel the improvements were worth it when driving, and forget about the numbers.
If you didn't take a rolling road measurement before making the upgrades, then you can only really guess at the difference it's made. What really matters is whether or not you feel the improvements were worth it when driving, and forget about the numbers.
MartyPubes said:
I don't know the answer, but why would any manufacturer under-quote the horsepower?
Today's bit of useless info - not your typical manufacturer I know, but Ruf quote the outputs for the least powerful development engine so that their customers' cars are always more powerful than expected.J4CKO said:
I spent about £700 on "tuning" an 8 valve Golf GTI, MK2, Superchip, Magnex Exhaust and an indiction kit and it made a princely 4.5 extra bhp over standard 116.5 versus 112, that may have been down to it being on good form as well, all the bolts on made more noise, but more power, hmm, not so sure !
That's why you should always get the car rolling roaded (on the same dyno) before and after you make any modifications.Rolling roads are notoriously variable, in any case, so their only real value is to give a comparative demonstration of 'before' and 'after' results.
Trust me, if you own a '340bhp' TVR Griffith, you're going to be very disappointed otherwise!
MartyPubes said:
I don't know the answer, but why would any manufacturer under-quote the horsepower?
Another potential scenario is insurance costs: manufacturers may not want a hot hatchback that's being marketed as younger drivers being lumbered with a higher-than-necessary insurance group, for example.J4CKO said:
and the ones down on power being M3 engines
A friend has an E36 M3, it has made 321bhp+ at two separate rolling roads so they do make the quoted power....sometimes!Relevant discussion here:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
for classic cars....back in the good 'ol days the manufacturers would pretty much just pluck an impressive number out of the air.
A lot of old American muscle cars have very conservative power ratings - something to do with less quoted power meant lower tax and insurance.
My favourite one is the case of the Boss 429 Mustang - basically a 1969-1970 Mustang with a NASCAR 429ci V8 engine squeezed in.
Ford said it had 375 bhp, but they actually made well over 500 bhp!
My favourite one is the case of the Boss 429 Mustang - basically a 1969-1970 Mustang with a NASCAR 429ci V8 engine squeezed in.
Ford said it had 375 bhp, but they actually made well over 500 bhp!
wackojacko said:
Jaguar XFR's do !
They are meant to make around 510 at the fly, I witnessed this at a Rolling Road day back towards the beginning of this year (Standard XFR)
you can't take that as gosable becouse its a estermate of power train loss the real only way of telling flywheel hp is on a engine dyno which is why people with tunned cars go for rear wheel horsepower it take the guess outThey are meant to make around 510 at the fly, I witnessed this at a Rolling Road day back towards the beginning of this year (Standard XFR)
SD1992 said:
A lot of old American muscle cars have very conservative power ratings - something to do with less quoted power meant lower tax and insurance.
My favourite one is the case of the Boss 429 Mustang - basically a 1969-1970 Mustang with a NASCAR 429ci V8 engine squeezed in.
Ford said it had 375 bhp, but they actually made well over 500 bhp!
I always thought the OPPOSITE was true???My favourite one is the case of the Boss 429 Mustang - basically a 1969-1970 Mustang with a NASCAR 429ci V8 engine squeezed in.
Ford said it had 375 bhp, but they actually made well over 500 bhp!
SD1992 said:
A lot of old American muscle cars have very conservative power ratings - something to do with less quoted power meant lower tax and insurance.
My favourite one is the case of the Boss 429 Mustang - basically a 1969-1970 Mustang with a NASCAR 429ci V8 engine squeezed in.
Ford said it had 375 bhp, but they actually made well over 500 bhp!
Is that the production one or the ringers they all supplied to the mags to test? My favourite one is the case of the Boss 429 Mustang - basically a 1969-1970 Mustang with a NASCAR 429ci V8 engine squeezed in.
Ford said it had 375 bhp, but they actually made well over 500 bhp!
The 4th gen Camaro/Firebird was supposed to make 305hp, the Corvette C5 345hp. When tested, the Firebird made nearly 300 at the back wheels and later 4th gens made 320 at the back wheels. The Corvette was lower than expected. Similar sort of stuff in later tests with a Mustang "Terminator" making 395bhp at the back wheels and a Camaro SS 317. All very impressive but I just don't trust rolling roads or how they calculate the figures.
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