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actual bhp
- Thread starter rickyboy
- Start date
The difference is because some 172s seem to come out of the factory down on power. I had a MK2 172 before my MK1 and it had 16bhp less at the wheels than another mk2 172 RRd the same day. Whats more, mine didnt get the lowest output that day
I dont think anyone has ever adequately explained why some are down on power. Two explanations that Ive heard are 1) some problem with the VVT and 2) squashed/bent/damaged air intake tubes.
Rich-D
ClioSport Club Member
E90 LCI 330d
AS has already been said, there will be a few of us going on the rollers this Saturday, so we should have a load of actual figures soon.
Its not 172bhp as we know it though, its 172ps or bhp/DIN which equates to ~169bhp in what we in the UK call "bhp" and should be about 143bhp @ wheels.
However, there seems to be quite a bit of variance between cars and quite a few have been known to make less, but others more, so unless you actually get your car on the rollers youll never know for sure!
Here we go again!
The Clio 172 and Cup BOTH make 172 bhp. This power figure is read using the DIN measurement standard. The DIN standard is almost identical to the SAE specification, but I believe the ambient temperature must be slightly lower to comply with the DIN specification (68 F), which leads to a mild power increase.
Everything else is the same. Engines must have all accessories installed and run the full production exhaust.
The Clio makes 172 bhp. If it were measured in SAE by Renault then it would make 169.64bhp, but Renault chose the use DIN, so 172 bhp is what it makes.
The new Porsche 911 (996) GT3 makes 381 bhp, and they have clearly used the DIN spec as it is a German standard, so you could argue it makes less if you were to convert to SAE, but they too chose DIN (as do so many other manufacturers).
The fact of the matter is that there is no standard BHP - you cant say, "DIN, whats that in BHP?"
Its like saying you owe me 10. 10 what? We know were talking about money, but 10 pounds is more than 10 US dollars!
GW Clio 200
Is that a lymeric
Rich-D
ClioSport Club Member
E90 LCI 330d
Would like to see what your @ wheels figure was from PE.
As for the Northampton one, the give you a 17% loss which is a little high, but not as OTT as some Ive seen which are way out.
Keeping that loss as a constant, means you would have 139bhp @ wheels from PE.
I reckon a spot on example should be ~ 143bhp @ wheels in an ideal world.
Elise/VX220/R26
Just to add my two penneth. I think that all 172s have near enough 172 BHP. (Due to miniscule manufacturing tolerances etc) Its far more likely that there are loads of dodgy rolling roads that are ill maintained and not callibrated properly. Rolling rodes when you think about it are quite a crude way of determining output from and engine which is many many moving parts removed from it (ie a big margin for error throughout the process)
Its just that the people on this forum that have experience of dynoing engines (as in more accurate than a Rolling Road for measuring flywheel output) have said that the F4R puts out 166bhp. I wouldnt have a clue as I havent had my engine dynod. Doesnt really matter at the end of the day, its only as fast as it is!
Elise/VX220/R26
Quote: Originally posted by Rhys on 19 November 2003
Quote: Originally posted by jonnyboy on 19 November 2003Purely the added up effects off all the variables of using a rolling road to test engine output. I rekon if you rrd a car in the morning and then came back in the afternoon and did it again there would be a difference. [/QUOTE]lol, carry on like that and no one will turn up on Saturday
lol yeah maybe I should shut up haha. I did look into loads or rolling roads and RE seemed to be the one most people had good things to say bout. Well lane are supposed to be spot on with their accuracy but they were such t**sers to deal with!
Guys, just to drop in a little bit of my own here.... transmission losses.....
when stone cold they are high - due to the gearbox oil not being warmed up to normal operating temperature, but if you have run the car around for a while then transmission losses drop quite a bit - now how are any RR operator that dials in a transmission loss meant to know what state the gearbox oil is? - they cant so unless they use rundown as a good estimate system the flywheel figures are going to be crap.
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