http://i109.photobucket.com/albums/n...mapImage-1.jpg
Printable View
added mine in as well ;o)
http://i109.photobucket.com/albums/n...itmapImage.jpg
Luke,
you were obviously running Detlef's 330bhp used NSX-R engine then;)
regards
Paul
I wish!!! I'll try and sort my real figs out soon and put them up when I have a couple mor eto update... I dont want to be the lowest curves!!!!Quote:
Originally Posted by Senninha
L*
Ok then ... here are my figures ...Quote:
Originally Posted by Lankstarr
RPM BHP lb/ft
1500 044 146
2000 062 164
2500 082 172
3000 100 178
3500 118 176
4000 132 178
4500 154 182
5000 178 184
5500 194 182
6000 216 192
6500 228 184
7000 242 190
7500 254 180
Just about the worst figures from the day ... but hey ... someone needs strong shoulders to hold everyone else up ... :!:
Still ... gives me a starting point ... which was the main purpose of the day for me ... looks like my baby hasn't been too well looked after before I got her ... although I do need to sort out the mixture as it's apparently running lean.
http://i109.photobucket.com/albums/n...r/nsxgraph.jpg
oops - keep forgetting to bring mine in!!
I'll make the graph a better scale and a lot clearer when I have a few more figs ;)
Paul - at 1500 rpm you are showing more torque than Senninha... you should be proud!!!
Indeed ... who's worried about getting to 60 quickly when ... round town I'll be beating everyone to 30 ... ;-)Quote:
Originally Posted by Lankstarr
Paul, like the new avatar! Any more news on the R8?
Finally got around to putting my figs up - interesting to see no difference between mine and Paul's 3.2 up to about 6k... then he pretty much walks away... his extra power all seems to be relieved in VTEC ie where it matters :D :
http://i142.photobucket.com/albums/r...itmapImage.jpg
I popped down to Surrey Rolling Road today and got 234 bhp at the wheels and 285 at the crank. What were the at the wheel figures for the original rolling road day?
Anyone have some numbers?
....I take it that's FWHP?
Quote:
Originally Posted by Lankstarr
All the figures were at the fly. The machine gave out those figures automatically. We weren't given any wheel figures.
That is a shame - it would be good to see the unadjusted numbers. The chaps at Surrey Rolling Road say that Power Engineering seem to adjust the flywheel figures by approx 20bhp more for Subarus - not sure how much the difference would be for 2WD.Quote:
Originally Posted by Kevin
My peak power was around 7300 rpm, with torque peak at 6500 - I plotted the numbers on my blog
http://www.noelwatson.com/blog/Perma...5d4560c45.aspx
It would appear that mine is another of the 3.2's that peak slightly higher than 6800, although I appreciate all rolling roads are different. It will be good to get on the TDI dyno in the New Year
Some other numbers I was given (at flywheel)
E46 M3 - 330 - no wonder they beat me at Bruntingthorpe
S2000 - 210
Civic Type R -197
Griff 500 - 270
Quote:
Originally Posted by NoelWatson
WOW, you must have one of the slower colours...red, I presume?! :)
Hi Noel,
Just got around to to looking at your power/gearing spreadsheet and graph. Interesting stuff.
Would you mind plotting a torque/gearing graph when you get some time?
The power/gear plot suggests it but one thing that the torque/gearing plot would certainly do is prove to any doubters, and there are always a few, that you MUST change up at the limiter if you want absolute maximum acceleration.
On the other thread you said that you were recording 160mph on the rev limiter at Bruntingthorpe? If so we may have the gearing figures slightly wrong. The table you refer to in the spreadsheet and I usually use from NSXPrime says 160mph at 8000rpm meaning we should be able to do 166mph at the 8300rpm limiter.
It's all somewhat acedemic but the pedant in me (oo-err Mrs) likes to know these things correctly :-)
Cheers
Mark
The S2000 would need to be a very poorly one to only have that at the fly, mine has managed between 237 and 260 depending on the mods at the time.
Quote:
Originally Posted by NoelWatson
Mark,Quote:
Originally Posted by markc
Will do the torque vs gearing in next few days. I would like to know what the limiter is. I think it is 8000 for a number of reasons
1). The dyno used 8000 for the limiter - if it were 8300 this would shift my peak power to around 7600 rpm - surely too high? (my torque peak was high at around 6300 assuming 8000 limit)
2). I have compared my GPS speed on limiter to these
http://www.nsxprime.com/FAQ/Technical/gearratios.htm
and they are spot on for 1st, 2nd and 5th (not tried the rest).
However, I'm more than happy to be proven wrong - how can we measure it?
Simon,Quote:
Originally Posted by simonprelude
I guess that Charlie has had more than one S2000 on his road so it was an average. Dan said the S2000 had the same number at his rolling road.
http://nsxcb.co.uk/testvb/showthread.php?t=3958
Maybe it is the type of dyno?
Mark,Quote:
Originally Posted by markc
Thinking about this, I'm not sure what torque vs. gearing would show us as we would have to scale it by the gearing to get tractive force at the wheels - I think this is what my original graph showed - unless I am missing something? i.e. My car will be producing less torque at 7500rpm in 3rd at 95 than in 4th at 5800 rpm but will still be accelerating more quickly
Regards
Noel
Noel,
I see what you mean, I think :) I took your data and plotted torque between 3K and 8K revs in each gear graph. Torque is on the y axis and speed is on the x axis. See pic...
Now I've confused myself.
Reading off the speeds at where torque in the lower gear is exceeded by torque in the higher gear does this, contrary to my earlier statement, prove that you don't have to change gear at the limiter for max acceleration? If not what the hell have I done?
The crossovers occur at the following speeds and revs 43mph (7,489rpm), 66mph (7,135rpm), 89mph (6,980rpm), 122mph (7,507rpm), 139mph (6,950rpm)
Confused but intriegued :)
Mark
That's what the graph says. So assuming you've calculated right, and graphed accurately it's what you say. You've proved yourself wrong!
It's probably worse in other that don't have the good torque curve of a Honda VTEC.
Hah, yes done in by myself :)
I'll wait for Noel to comment as I used his data, spreadsheet and graph. I just input his torque (at the wheels) results into the graph and changed the x axis scale and titles.
I'll be amazed if this, that you can change up this early and still have more torque hitting the road, is true. It must be very unusual!
Please someone prove me wrong, I don't want to have to start changing up early and miss out on upto 1,300rpm's worth of VTEC nirvana so that I can go faster :)
Mark
If I am reading that right you need to change up to 6th at 140mph on a vmax run ??
Yes Simon, that's what my graph says... I NEED someone to look at the data and prove it wrong!
Mark
I'll see if I have some time :(
Quote:
Originally Posted by markc
Hopefully we can test it out, by doing a run for one car at TDi, once in 2nd gear and one in 3rd.
Quote:
Originally Posted by markc
Quote:
Originally Posted by markc
Mark,
Maybe using the term "torque at the wheels" is a bit misleading, because this will be a function of gearing. This site explains it better than I can - the lower the gear, the greater the torque multiplication.
http://www.mustangsandmore.com/ubb/D...orqueVsHP.html
I did all this in my Engineering degree donkies ago, forgotten most of it, but am pretty certain that a graph of torque at the wheels without taking into account gearing is misleading.
We still need to what out what the rev limit is!!
Just to bring back this old thread....again
I've been doing a little reading.
Fact 1. The BHP figure and ft/lb figure are numerically the same at 5253rpm. This is due to the way BHP is calculated from torque. So on a graph, BHP and TQ always cross over at 5253. If they don't suspect something.
Fact 2. HP = TQ * RPM / 5253.5
I've been playing with a calculator, and seems some of the figures below don't add up.:)
So at 6500RPM, the HP should be 277, given the TQ number. However at
7000rpm the HP is 290.
With the competitive nature of some people here, those 1 or 2 hp here and there make all the difference.:)
I realise the figures came from the graph so errors will creep in, next time, we need hard figures not graphic printouts.
Every little helps.
Quote:
Originally Posted by Senninha
I've been obsessing about this and with the help of Noel and Kevin now understand why the torque vs speed graph I plotted is utter bo!!ocks :) Essentially it makes no allowance for gearing ie torque multplication.
So, I made a statement (that you ALWAYS have to shift at the limiter for max acceleration), then apparently proved myself wrong (with said graph), then disagreed with myself, and finally I've proved myself to have been right in the first place! Schizophrenic or wot ;)
Anyway... Kevin built a spreadsheet which properly allowed calculations and graphs of torque vs speed to be plotted. I have added a number of variations of NSX model years and gearing options, including tyres to illustrate the effect. I used the power and torque outputs from Kevin's car in all instances. (attached zip file)
Graphs of the two extremes, a bone stock 1991 car on rear 225/50/16's and a Short geared, 4.44:1 diff car on 245/45x17's are pictured below.
Please feel free to comment on correct any faults you find in the spreadsheet.
One exercise I want to do with this info and these graphs is to calculate the area under each curve (total torque) and the aggregate of this for each sample car/gearing/tyre combination.
I do know I need to get out more.... :)
Cheers
Mark
Where's the six speed graph which shows how the 6 speed delivers torque to the road better than a 5 speed?
What we can do now is get the formulae from Bob Butler off NSXPrime. Given the torque curve and gearing, and weight of a car, it should be possible to then calculate the velocity of a car over a given distance. The velocity would have to be worked out by integrating the acceleration or something like that.
Then, some more meaningful figures will be produced. 0-60 times don't mean much. What does mean something is over a 1/2 mile, if two cars started at the same time, at 0mph who would cover the distance the fastest and by how much or how far.
Spreadsheet racing is much cheaper than the real thing.:)
Quote:
Originally Posted by Kevin
I think it would be useful to get our cars on a weighbridge. If anyone fancies doing this in the Surrey area let me know. We also need to think about aerodynamics. Honda claim the 2002 NSX was 0.1 second quicker to 125 thanks to improved aerodynamics. Not sure how the 97 changes affected drag
Sorry the zipped spreadsheet file didn't upload, I've edited my previous post and uploaded it there.
The 3.0ltr with 6spd plot is there as is a stock 1996 (shorter gears) and NSX-R.
Noel the rev limiter is definately 8,300rpm, for all model years. I don't know why most rolling road NSX pulls only read to 8,000rpm?
I'm Lightwater in Surrey based. Very happy to stick my car on a weighbridge, but being primarily for 10ton+ lorries are they accurate enough at lower weights? What about proper race scales, anyone got a set or know someone who has?
Spreadsheet racing is the best :)
Mark
Mark, the 8000 is entered by the machine operator. If 8300 is correct, my torque peak is near around 6600 and power around 7500 - does this sound a bit high? It also means the figures are wrong on the NSXPrime site so we will have to take that into account for our calculations.Quote:
Originally Posted by markc
Noel, I think you're saying that your measurements could be scewed by the machine thinking that 8,300revs is actually 8,000revs? I don't think this is the case.
The dyno should use a clip/clamp of sensor which connects to one of the cars ignition leads so that it can measure the number of ignition pulses and therefore (because you tell the machine how many cylinders the car has) the revs. It therefore knows the engine revs and measures the power/torque generated athose revs.
I'm guessing that the operator enters the maximum revs that the run will be made to and then does the run. The machine stops measuring at whatever the maximum entered revs was, even if the car actually continues on to a higher number, before measuring the drivetrain losses during coastdown?
Mark
Mark,Quote:
Originally Posted by markc
Can't comment on what Power Engineering do, but Surrey Rolling Road don't attach any form of rev measuring equipment to the car. They run the car up to the limiter and then type into the dyno what they think the limiter is - for my run 8000 was entered.
The type of rolling road at SRR uses a lookup table to calculate drivetrain losses rather than the coastdown method.
If you fancy going for a dyno one weekday evening let me know - I will put my car on Optimax and reset ECU to see if I can beat 285!!
Regards
Noel
It sounds like a lot of assumptions and calculations and reading the rev counter being used there.
Dyno's usually only go to 90 - 95% of the rev limiter to avoid engine damage.
Max power and max torque come in before there anyway so in the eyes of the rolling road operator there is no need.
Not sure why it would damage the engine any more than on the open road?Quote:
Originally Posted by simonprelude
Maybe, but I think the methodology of using the lookup method for loss is common for that type of rolling road. I mentioned previously that SRR reckoned it gave a lower flywheel reading for Scoobies than Power Engineering.Quote:
Originally Posted by Kevin