My AX22 tests
#106
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Jean, don't worry, I believe you... - if you use right equations.. but as I have seen, you do.. and if you don't remember what those were, I can fetch them from my file achieve
I use those same ones. I learnt them in school but rechecked them from Bosch's automotive "some-name" book in beginning 2004 when we published first version of that obd software.
So back to topic, here is your earlier question
can you please tell me what my HP and torque is for this data point only
Long G: 0.40
Speed: 129 Mph
CD: 0.34
Area: 1.93
Stock 993TT gearbox: 5th gear
Total weight: 3300 lbs
Tires: 305 x 30 x18
Here it reply again but now with my runs in same data point.
I have used 1500kg, 315mm tire and 12% transmission lost(2WD) for your calc.
and 1480kg, 295mm tire and 17% transmission lost(4WD) for my car
Nm kw hp Comment
796 491 667 Jean, ver 6 probably?
739 464 631 me run 30.8 ver.7
867 545 741 me run 30.8 ver.6
803 504 686 me run 28.8 ver.6 you have that run Jean
723 454 617 me run 28.8 ver.7 you have that run Jean
So that version version 7 is very odd.. but I assume that you use version 6, am I right?
I use those same ones. I learnt them in school but rechecked them from Bosch's automotive "some-name" book in beginning 2004 when we published first version of that obd software.
So back to topic, here is your earlier question
can you please tell me what my HP and torque is for this data point only
Long G: 0.40
Speed: 129 Mph
CD: 0.34
Area: 1.93
Stock 993TT gearbox: 5th gear
Total weight: 3300 lbs
Tires: 305 x 30 x18
Here it reply again but now with my runs in same data point.
I have used 1500kg, 315mm tire and 12% transmission lost(2WD) for your calc.
and 1480kg, 295mm tire and 17% transmission lost(4WD) for my car
Nm kw hp Comment
796 491 667 Jean, ver 6 probably?
739 464 631 me run 30.8 ver.7
867 545 741 me run 30.8 ver.6
803 504 686 me run 28.8 ver.6 you have that run Jean
723 454 617 me run 28.8 ver.7 you have that run Jean
So that version version 7 is very odd.. but I assume that you use version 6, am I right?
I knew you spent a lot of time using the search button on Rennlist but I had underestimated the amount of posts you have read here and the info you took with you!
The version 7 from thesoftware is not a commercial version, it is still under testing apprently and should not be used.
I will give this a quick shot, I will take the example for your car.
Before starting, you need to keep in mind that in order to do HP and torque calculations, you need to smoothen the long G data to reduce parasitic information.
Th edevil is in the details! In your case, the 0.4G at 209 kph is clearly an aberration. Look at the trend in the long Gs before those spikes at around 209kph, you will see that you are trending at 0.36 at around 207 kph and dropping from there obviously.
I have attached two close up charts to make it clearer. In the first one you see how there are some spikes at the 209kph level,
and in the second one which is a close up, you clearly see that the data cannot be used from that datapoint in particular (good choice of datapoint though ) at 129mph, you would be in reality below 0.36Gs. At that point you are at around 5612 RPMs.
With the above in mind, let us calculate your HP and torque at that point excluding drag.
Long G: 0.36
Speed: 129 Mph
Stock 993TT gearbox: 5th gear
Total weight: 3260 lbs
Tires: 295 x 30 x18 => Tyre OD in (In)= 25.0
Kph /1000 RPM: 60000*(PI*25.0/10^6)/3.227028))= 37.0
=>RPM at 207.66kph (129mph): 207.66/37*1000= 5,612 RPMs
FWTQ= 0.36*3260*25.0/2/12/3.227028/0.17 = 462 lbs = 626.4NM of torque.
FWHP= 626.4 x 5612/5252= 484.4 FWHP =361.2 KW
So at this datapoint in particular, you had about 626 NM of torque and 484 FWHP, excluding drag. You can imagine that we are very far away from your calculated 867NM! If you had 867NM, I would be betting that you ran beyond 1.3 Bar of boost, that BMEP does not lie.
I hope we don’t have to debate the calculations, they are very straightforward
The other items (negative acceleration items) are not included here.
As to the other uses of these formulas such as max speed etc.., what you posted is just the beginning basic stuff , once you get to simulate quartermile times and speeds for every RPM point, acceleration within gears from xxmph to yyy mph, up to what speed you have wheel spin with different tires and gears, impact of gearing, traction and gear changes across a 0-320kph etc.. this is when all this becomes interesting, been doing this for a few years now with real life data to validate.
#107
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
It's hp that gives you top speed. From memory the factory quoted that the 408 hp car had a top speed of 290 kph and the 430 car a top speed of 300 kph. The 430 engine has the same max torque as the 408 car. It has more hp at the top end due to a boost increase (1.1 bar or so) at 5500+ rpm.
Phelix is 100% right, It is HP not torque.
#108
thx, exactly what I should have had calculated before having the taller 6th gear installed :-)
What is the "typical" max hp of a 993 tt engine that is capable of delivering 550NM@6900rpm?
600+hp?
What is the "typical" max hp of a 993 tt engine that is capable of delivering 550NM@6900rpm?
600+hp?
#110
Addict
Rennlist Member
Rennlist Member
550NM @6900rpm = 404.4lb/ft
to work out the hp at 6900rpm: 404.4*6900/5252 = 531hp - so that is probably the maximum hp for that tt motor. The torque will typically be higher since that is made further down the rev range.
#112
Toby, I know that formula.
My question was what maximum (peak) hp a typical 993tt engine would have to still have 530hp at redline because most air cooled tt engines drop power dramatically at higher rpms.
My question was what maximum (peak) hp a typical 993tt engine would have to still have 530hp at redline because most air cooled tt engines drop power dramatically at higher rpms.
#115
Addict
Rennlist Member
Rennlist Member
I see what you mean now......
I don't think there is really a "typical" 530hp and above 993tt engine is there ? I know the ~520-550 ones Schmirler has been doing lately with the big exhausts and cats seem to keep 90% of their power to 6900......
#116
It seems that it would be a simple task for you guys to create a Excel spreadsheet that gives the perfect gear ratio for top speed for a given torque curve or that calculates the needed hp for a given gear ratio...
In theory all you 3 guys had enough horses to go 330+ kph with the right gear ratio.
In theory all you 3 guys had enough horses to go 330+ kph with the right gear ratio.
#117
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
It seems that it would be a simple task for you guys to create a Excel spreadsheet that gives the perfect gear ratio for top speed for a given torque curve or that calculates the needed hp for a given gear ratio...
In theory all you 3 guys had enough horses to go 330+ kph with the right gear ratio.
In theory all you 3 guys had enough horses to go 330+ kph with the right gear ratio.
#118
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
It is not torque,it is HP, of course they are related, but since torque is irrelevant of RPM , while what makes your car go faster is HP at high RPMs ( => torque).... An F1 car has a lot of HP or torque??
#119
Pro
Thread Starter
Join Date: Nov 2005
Location: on the road..
Posts: 578
Likes: 0
Received 0 Likes
on
0 Posts
I used "real porsche style hp"
#120
Pro
Thread Starter
Join Date: Nov 2005
Location: on the road..
Posts: 578
Likes: 0
Received 0 Likes
on
0 Posts