Power/Torque Curve
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and that's why some of us use a COBB AP.
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äääääeeemmmmmmm,Accessport will cure that
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tbh,i think Nissan expected too much abuse from us europeans and just made the mapping far too safe...thats the reason the GTR doesn´t do 310km/h...
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Heres a question , when is the best time to shift to maximize acceleration ?
Peak power ?
Peak torque ?
Redline ?
Somewhere else ?
Now with that said if you look at a dyno chart of a stock car with boost overlaid you will see that boost peaks at around 3000 rpms and starts to drop down to about 10 psi after 5000 rpms.
This is why companys sell aftermarket wastegate actuators, and Cobbs new boost control vs RPM does what it does. Keeps boost higher though the higher rev range.
The stock turbos on the R35 are pretty small, and they will do what small turbos do, run out of capacity at high RPM, boost, and you will see that nose over. The trade off is good response vs high rpm power.
Peak power ?
Peak torque ?
Redline ?
Somewhere else ?
Now with that said if you look at a dyno chart of a stock car with boost overlaid you will see that boost peaks at around 3000 rpms and starts to drop down to about 10 psi after 5000 rpms.
This is why companys sell aftermarket wastegate actuators, and Cobbs new boost control vs RPM does what it does. Keeps boost higher though the higher rev range.
The stock turbos on the R35 are pretty small, and they will do what small turbos do, run out of capacity at high RPM, boost, and you will see that nose over. The trade off is good response vs high rpm power.
You'll want to shift so that your current gear and the next gear get the most area under the dyno.
So if you have a dyno print off and on each gearshift you 'lose' 2000 rpm of engine speed then you want to find the 2000rpm range on the dyno bhp graph that has the most area underneath it.
Of course it gets a little more complicated as the gears will not have exactly the same spacing between them so you'd need to calculate for each shift (but that error is probably not significant as they won't differ that greatly)
Torque has little to do with acceleration (except that its a component of power), its all down to how much power you have and for how much of the rev range you have it.
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without new turbo's and injectors........get a new map the latest greatest :smokin:and short shift 1st 2nd 3rd with Traction control OFF (you have to short shift at around 4800 to 5000 rpm or you will light them up in the dry) then for all other gears there is a balance between torque and BHP with stock turbo's and injectors the torque drops off dramatically after 5300rpm so would suggest based on what i have seen shifting at around 5600 rpm as peak BHP is still up around 6400rpm but torque drop dramatcally after 5300rpm. But it is a balance and depends who is tuning you motor. If stock for me what i remember of when i had stock map best to shift around 5400rpm for best you can get. I AM SURE OTHERS WILL DISAGREE
But logically acceleration is generated as a result of power and not torque (if we need to get to 100mph then we need to generate the kinetic energy required from the engine, and power is energy per unit time), so for maximum acceleration one would need as much bhp as possible for as long a period in the rev range as possible, which would most likely be by staying in gear through peak bhp. If someone has a dyno sheet to dissect and some shift data then we could work it out exactly.
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I think this sums it up nicely imho (assuming dyno = power plot graph).
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Interesting this as best terminal was acheived short shifting??? Cant wait for dry track as suspect it was all due to lack of traction now
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Volumetric efficiency peaks at peak torque and then declines. Less airflow, less torque. However, power increases as long as torque declines slower than RPM increases.
You can increase the boost whilst the turbo is still efficient to gain power at the top, but you tend not to change the shape of the curve much, just lift it higher.
Bigger turbos and cams would shift it higher at the expense of driveability.
Is this what you wanted to know? This is nothing special about the GTR, it is generic to all consumer turbocharged engines, and most NA engines except Honda, BMW M power.
You can increase the boost whilst the turbo is still efficient to gain power at the top, but you tend not to change the shape of the curve much, just lift it higher.
Bigger turbos and cams would shift it higher at the expense of driveability.
Is this what you wanted to know? This is nothing special about the GTR, it is generic to all consumer turbocharged engines, and most NA engines except Honda, BMW M power.
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A little to tech but I think I understand, I came from a RS4 to a GTR and the power didn't kick in until 5k so I guess it's kinda weird for me.
Would a remap help with this sort of flat spot? long term I'll probably get an exhaust and Cobb.
Would a remap help with this sort of flat spot? long term I'll probably get an exhaust and Cobb.
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