LS 460 Dyno Test
08-08-15, 12:41 AM
#1
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LS 460 Dyno Test
Hello, I'm owner of Lexus LS 460 '08 RWD with 95,000 miles. Yesterday I made Dyno Test of my car and in my opinion the results are bad. Is anyone doing a dyno test for LS 460 to compare the results?
Is dyno test should be doing in normal mode or pwr ?
08-08-15, 03:27 AM
#2
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Welcome to Club Lexus!
Can't read the words to know what is plotted, but something looks wrong with your dyno or the dyno scale. HP and torque should cross at 5252 RPM on every dyno
hp = (torque x rpm) / 5252
The only other dyno I found posted is here though and also doesn't cross there but the numbers look consistent with a 20 pct drivetrain loss
http://www.rri.se/popup/performanceg...p?ChartsID=750
Can't read the words to know what is plotted, but something looks wrong with your dyno or the dyno scale. HP and torque should cross at 5252 RPM on every dyno
hp = (torque x rpm) / 5252
The only other dyno I found posted is here though and also doesn't cross there but the numbers look consistent with a 20 pct drivetrain loss
http://www.rri.se/popup/performanceg...p?ChartsID=750
Last edited by DaveGS4; 08-08-15 at 03:33 AM.
08-09-15, 12:46 PM
#5
Is this an American spec car?
08-09-15, 09:04 PM
#7
Driver School Candidate
TS graph is in newton meters hence we will not see the intersection at 5252rpm.
The appropriate formula in this case should be Horsepower = (nm x rpm) / 7121
Plucking some figs from the graph above and working backwards,
418nm at 3920rpm translate to 230.1hp
308hp at 6199rpm would translate to 353.8 nm
Both numbers correspond to their respective points on the graph and hence probably legitimate.
Alternatively, you can convert nm to lb/ft first and compute using the 5252 formula.
Rpm at which the peak torque/hp are made look a little early compare to factory specs at 4100/6400 though.
Last edited by Vvman; 08-10-15 at 05:15 AM.
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08-10-15, 04:21 AM
#8
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Well, seems there are several opinions. Who's an engineer here? Let's get an absolute answer converting metric figures to American HP. I tried to Google to this morning and didn't find any clear answer. Need more coffee 
Last edited by swfla; 08-10-15 at 04:29 AM.
08-10-15, 07:56 AM
#9
Driver School Candidate
I am no engineer nor mathematician but the hp formula is really
HP = (rpm x torque) / 5252 where torque unit is in lb/ft.
Converting torque in lb/ft to nm, just multiply by 1.3558 and you will have
HP = (rpm x [torque x 1.3558]) / 5252 x 1.3558 where torque unit is in nm while HP is fixed.
Hence, HP = (rpm x torque in nm) / 7121
With reference to the dyno chart above, at 5200 rpm (pretty close to 5252 rpm) on the horizontal axis, the corresponding torque chart shows an estimate 375 nm, hence we have
HP = (5200 x 375 nm) / 7121, giving approx. 273.8 hp.
This corresponds roughly to the same figure. (ie 273.8 hp) on the HP curve above. Pretty spot on to the intersection we would expect at 5252 rpm.
HP = (rpm x torque) / 5252 where torque unit is in lb/ft.
Converting torque in lb/ft to nm, just multiply by 1.3558 and you will have
HP = (rpm x [torque x 1.3558]) / 5252 x 1.3558 where torque unit is in nm while HP is fixed.
Hence, HP = (rpm x torque in nm) / 7121
With reference to the dyno chart above, at 5200 rpm (pretty close to 5252 rpm) on the horizontal axis, the corresponding torque chart shows an estimate 375 nm, hence we have
HP = (5200 x 375 nm) / 7121, giving approx. 273.8 hp.
This corresponds roughly to the same figure. (ie 273.8 hp) on the HP curve above. Pretty spot on to the intersection we would expect at 5252 rpm.
Last edited by Vvman; 08-10-15 at 09:19 AM.
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