30th September 2006 Rolling Road Day

[markc]

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

[NoelWatson]

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

Mark,

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?

[NoelWatson]

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

Mark,

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

[markc]

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

[Kevin]

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.

[markc]

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

[simonprelude]

If I am reading that right you need to change up to 6th at 140mph on a vmax run ??

[markc]

Yes Simon, that's what my graph says... I NEED someone to look at the data and prove it wrong!

Mark

[Kevin]

Hopefully we can test it out, by doing a run for one car at TDi, once in 2nd gear and one in 3rd.

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

[NoelWatson]

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

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!!