Rolling road at Brands what BHP ?
Discussion
I noticed several owners put their cars on the rolling road at the Brands driving day last month. What sort of bhp figures were achieved on the 3Rs as one chap I spoke to the other day mentioned his car was quite well down because of a fault with the actuator/ BOV ???? Anybody shed some light on this ??
alex s said:
i watched 3 or 4, all were well below quoted figs, except adrian w's with a impressive 440 ft/lb of torque!! but his is deffo not standard!!
The 374 bhp 3R was the Noble motorsport one i think.....was it gold?
If I remeber the motor sport Gold one hit 391BHP (flywheel) but on motor sports road it was said to be 440. The guy from motor sport came over to chat with Mike (Dyno) not sure what was said. The Dyno road seemed to be accurate he called it the "Ego Killer". My 2.5 with std ECU cracked manifold and it looks like down a bit on boost only hit 288BHP. It goes in to Matt's in march to get sorted.
Mike said the std 3R's were +20BHP down from quoted level
Bondy
Dunno how much I trust dynos, although one of those ones pictured measured a GT3 RS at 420bhp in shootout mode (which is meant to give reproduceable accurate results so people can't fudge it for their mates/clients etc - they make a very big deal out of this). The fact the RS got 420 makes me skeptical of it's accuracy though
Normally they pull low 400s although Porsche only claim 381bhp. http://stuttgart9.co.uk/upload/showth
mgbond said:
If I remeber the motor sport Gold one hit 391BHP (flywheel) but on motor sports road it was said to be 440. The guy from motor sport came over to chat with Mike (Dyno) not sure what was said. The Dyno road seemed to be accurate he called it the "Ego Killer". My 2.5 with std ECU cracked manifold and it looks like down a bit on boost only hit 288BHP. It goes in to Matt's in march to get sorted.
Mike said the std 3R's were +20BHP down from quoted level
Bondy
Bondy, I think I've got your dyno run on tape, I'll have a look for it tomorrow.
Anthony
www.pumaracing.co.uk/ makes a facinating read about RRs and how they turn "wheel" torque into "flywheel BHP".
J
J
One man's accurate seems to be another man's inaccurate given what's written above about Motor Sports and Dyno
Just pointing out there is much debate around this...
The only thing that seems certain is any EU type approved car can only be +-2% according to an engine development engineer at Lotus that used to post on the old Lotus Owner's club forums.
If anyone's read Dave Walker's ramblings in Circuit Driver it makes interesting reading about the whole subject.
J
Just pointing out there is much debate around this... The only thing that seems certain is any EU type approved car can only be +-2% according to an engine development engineer at Lotus that used to post on the old Lotus Owner's club forums.
If anyone's read Dave Walker's ramblings in Circuit Driver it makes interesting reading about the whole subject.
J
joust said:
One man's accurate seems to be another man's inaccurate given what's written above about Motor Sports and Dyno Just pointing out there is much debate around this...
The only thing that seems certain is any EU type approved car can only be +-2% according to an engine development engineer at Lotus that used to post on the old Lotus Owner's club forums.
If anyone's read Dave Walker's ramblings in Circuit Driver it makes interesting reading about the whole subject.
J
Joust, they can be way over +2% - just look at the Skylines & NSXs that kept to the gentleman's rule, or indeed several Porsche models. Not even sure they can't be below quoted depending on what standard is used as air pressure, temp & etc all affect it and this stuff doesn't seem to really be regulated.
FWIW that type of dyno seems to have a decentish rep - its the same type that Evo mag uses, which has made several manufacturers look a little optimistic.
Did you have fans on the cars to simulate airflow btw?
joust said:
One man's accurate seems to be another man's inaccurate given what's written above about Motor Sports and Dyno Just pointing out there is much debate around this...
The only thing that seems certain is any EU type approved car can only be +-2% according to an engine development engineer at Lotus that used to post on the old Lotus Owner's club forums.
If anyone's read Dave Walker's ramblings in Circuit Driver it makes interesting reading about the whole subject.
J
Its 5% as far as i know, and there seems to be no stipulation as to how that power fig must be attained, companies running engines with no exausts and air conditioned air feeds is not unheard of..
Chassis Dynos are incredibly accurate and usefull tools, its shame no one trusts them anymore because so much fiddleing has gone on for years in the industry
DanH said:
Joust, they can be way over +2% - just look at the Skylines & NSXs that kept to the gentleman's rule, or indeed several Porsche models. Not even sure they can't be below quoted depending on what standard is used as air pressure, temp & etc all affect it and this stuff doesn't seem to really be regulated.
I refer the honourable gentleman to
www.pistonheads.com/gassing/topic.asp?t=53815&f=9&h=0&hw=nick+adams
Sorry - it was +/- 5%, as stated in my quote of Nick Adams on page 2 of that thread, but he definatly said + or -.
Regards,
J
vixpy1 said:Correct - sorry, just corrected myself after I found the quote - Nick said that the Elise engine was generally built to 3 or 2% which is what I got confused on.
Its 5% as far as i know, and there seems to be no stipulation as to how that power fig must be attained, companies running engines with no exausts and air conditioned air feeds is not unheard of..
Chassis Dynos are incredibly accurate and usefull tools, its shame no one trusts them anymore because so much fiddleing has gone on for years in the industry
Engine BHP figures can be measured without the gearbox or drivetrain it seems as well, so someone trying to replicate the manufacturers figures with those bits attached, even if you use coastdown to try and estimate the losses, seems to be a bit of a black art.
As the M12 isn't type approved though these don't apply, so I think we are a bit in the land of the gods. What is certain is an M400 has significantly more than 3R though!
What would be interesting is if the different models showed the appropiate %age differences I suppose?
J
joust said:
Engine BHP figures can be measured without the gearbox or drivetrain it seems as well, so someone trying to replicate the manufacturers figures with those bits attached, even if you use coastdown to try and estimate the losses, seems to be a bit of a black art.
Well, all munufactuers use an engine dyno to measure the bhp. Strictly, all we in the chassis dyno world can only measure what car does at the wheels, the rest, despite what people claim about coast down (it seems too unrelaible to me, i don't trust it) is always an estimate. Ours is just particulary accurate estimate, but then i would say that
Everything would be better if everyone just stuck to wheel figs, like the lancer forum does.
However, there is more chance of Cherie running off with Gordon Brown than that happening
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- although there seems to be hot debate on the evo forums about that!