Evo8+ fpevo green=400/362

[mcwop23]

that graph that converted the MPH to RPMs shows peak power at 5500-5900. Isn't that low in the power band or is it because it was done with a 3rd gear pull?

[Fourdoor]

Originally Posted by mcwop23

that graph that converted the MPH to RPMs shows peak power at 5500-5900. Isn't that low in the power band or is it because it was done with a 3rd gear pull?

No, the problem is in the dyno calibration, it shows the cross over point between torque and HP at 57 mph in 3rd gear.... that comes out to be 4800 RPM. The actual cross over point for torque and HP would be 5250 RPM, so this dyno has a 450 RPM offset in it's readings.

Keith

[4tun8]

In relation to how TT's dyno reads, I made 397 and trapped 119 a few days later.

I'm more curious to see this turbo with a milder cam on a flash

[blockhed79]

Buschur race core, ported exhaust mani and revolvers going in soon...

[6thfloor]

I'm sorry this is probably a dumb question but why in the world does the torque and hp have to cross at 5250 RPMS? I am understanding that they cross at that point no matter the config, and that does not make sense.

forced performance rocks.

[JohnEB]

Originally Posted by 6thfloor

I'm sorry this is probably a dumb question but why in the world does the torque and hp have to cross at 5250 RPMS? I am understanding that they cross at that point no matter the config, and that does not make sense.

forced performance rocks.

Because torque and rpm are divided by 5252, torque and horsepower are always equal at 5252 rpm. If you solve the equation at 5252 rpm, the rpm value cancels out, leaving horsepower equal to torque. If you plot torque and horsepower curves on a graph, the lines will always cross at 5250 rpm (rounded off). If they don't, the curve is undoubtedly bogus.

Torque is the static measurement of how much work an engine does, while power is a measure of how fast the work is being done. Since horsepower is calculated from torque, what we are all seeking is the greatest-possible torque value over the broadest-possible rpm range. Horsepower will follow suit, and it will fall in the engine speed range dictated by the many factors that affect the torque curve.

Horsepower is what you read about, torque is what you feel.

[Evolvd]

Or in simple terms I like to use...Torque is how much pull you have, and Horsepower is how effecient your car is using that "pull".

Horsepower doesn't really exist...it's an unprecise measurement derived from a formula made up by some math geek.

BTW, the second dyno chart which was edited with RPM's is off. The lines cross below 5250...FYI.

[Fourdoor]

Originally Posted by Evolvd

Or in simple terms I like to use...Torque is how much pull you have, and Horsepower is how effecient your car is using that "pull".

Horsepower doesn't really exist...it's an unprecise measurement derived from a formula made up by some math geek.

BTW, the second dyno chart which was edited with RPM's is off. The lines cross below 5250...FYI.

It is off because that dyno is jacked up.... not because of the math... Just FYI there.

Keith

[Evolvd]

How did you come to that conclusion? If the Dyno is jacked up can we be certain that the hp/tq numbers posted are accurate?

[Fourdoor]

Originally Posted by Evolvd

How did you come to that conclusion? If the Dyno is jacked up can we be certain that the hp/tq numbers posted are accurate?

They are not accurate, that was the whole point of figureing out the RPM numbers based on the original graph and knowing what gear the dyno pull was made in.

I never trust a dyno graph with speed as the lower axis of the graph, becuase RPM plays a huge factor in the results on the dyno. Easiest way to tamper with dyno results is to use a bogus mph to RPM conversion in the dyno software.

Extreme example:

Lets say we have a car that makes peak HP at 4000 RPM and it makes 300 HP at 4000 RPM. That would mean you are making 393.9 lb-ft of torque at 4000 RPM. Now if you convince the dyno that the car is actually at 6000 RPM when in reality it is at 4000 RPM, it will be convinced that the car is making that same 393.9 lb-ft of torque at 6000 RPM which translates to 450 wheel HP.

If you have an actual RPM signal from the engine going to the dyno, you can not fool it in this way... but if you don't use the RPM signal from the engine you need to input a "road speed to RPM conversion factor" into the dyno. If you do it correctly you get accurate results.... if you fudge the numbers a bit, your customer gets a really nice braging rights dyno sheet. For this reason I never trust a dyno sheet that reads in mph unless I do the numbers conversion for RPM.

Keith

[Evolvd]

I follow ya. I've only been on two dynos and both hooked up to the OBDII port IIRC to read RPM.

[6thfloor]

I don't know if it was a dumb question or not, but I understand now. So is this a bogus thread? Can the graph be replotted for hp with a correction of howmany RPMS it is off? Racking my little brain I figure the data is totally corrupted. When I do my own hp calculation, witch I had to learn to understand the 5250 thing, I find that my numbers follow the graph when I ad 450 rpms but when I recalculate the given points to the given RPMs the hp is around 30 hp to high.

Based on the RPM graph
330ft/lbs@5900 RPMS graph=370hp NOT 400
330ft/lbs@5900+450 RPMS =398hp

Have I melted my newbian mind for nothing?

[turbolarry]

Just take it for what it's worth. It's the internet.