[Aramis1919]

Three runs, or pulls.

Run one....427 BHP and 468 FT-LB of torque.

Run two.....435 BHP and 471 FT-LB of torque.

Run three...445 BHP and 475 FT-LB of torque.

Not bad for a little M-lite and way ahead of the 369 BHP/369 FT-LB torque claimed by BMW for UK registered cars.

Dyno chart print out at end of video.

[MPR]

Mods?

[Aramis1919]

Originally Posted by MPR

Mods?

A used JB+ from Ebay for £25. Nothing else.

Oh...and 99 octane petrol when I can get it. I believe this be broadly similar to 93 octane petrol in the US.

[nikman011]

I can’t read the numbers on dyno sheet, how does that translate to WHP?
Thanks!

[Aramis1919]

Originally Posted by nikman011

I can’t read the numbers on dyno sheet, how does that translate to WHP?
Thanks!

It's 445 BHP at the crank, the same place BMW say 369BHP lurk.

Wheel horse power is probably around 16% less....roughly 373 BHP. It's difficult to give a definitive figure.


Mustang dyno used which I hear gives lower figures than the Dynojet dyno.

[Aramis1919]

In reality most G42 M240i make around 400BHP/400FT LB as standard.

I think BMW play down the figures as they want plenty of clear water between it and the M2.

[Pentland]

Originally Posted by Aramis1919

It's 445 BHP at the crank, the same place BMW say 369BHP lurk.

Wheel horse power is probably around 16% less....roughly 373 BHP. It's difficult to give a definitive figure.


Mustang dyno used which I hear gives lower figures than the Dynojet dyno.

I think you need to back to school 369-16% ≠ 373.

BMW hp, measured at the crank, for a standard uk car is 374hp.
I’d be surprised a) if BMW underrate their cars by as much as 10% as an earlier post suggested b) that jb + would add more than 10%.

Numbers aside, the car is quick, the data is just pub bragging points.

[Aramis1919]

Originally Posted by Pentland

I think you need to back to school 369-16% ≠ 373.

BMW hp, measured at the crank, for a standard uk car is 374hp.
I’d be surprised a) if BMW underrate their cars by as much as 10% as an earlier post suggested b) that jb + would add more than 10%.

Numbers aside, the car is quick, the data is just pub bragging points.

My maths is fine.

Standard UK car is 374 PS ( German measurement I think) which equates to 369BHP.

The 16% figure is taken from 445BHP not the 369BHP.

All I know for sure is that it produced these figures. Perhaps it is just a good example and then when you add the JB+ and 99 octane petrol.

[SeanJP]

Sometime I need to look up how Metric, European horsepower is calculated. I know it’s not too far off, but I don’t remember if it’s higher or lower than American SAE horsepower: Torque (in pound feet) X RPM / 5252

[Aramis1919]

Originally Posted by SeanJP

Sometime I need to look up how Metric, European horsepower is calculated. I know it’s not too far off, but I don’t remember if it’s higher or lower than American SAE horsepower: Torque (in pound feet) X RPM / 5252

American SAE horsepower?

I know exactly how this is calculated accurately.

1. Think of a very large number.
2. Double it and add 50% for luck.

I believe SAE is the same as Gross horsepower......which was replaced by lower 'DIN figure about 50 years ago.

[mike@x-ph.com]

Whats your baseline?

[Aramis1919]

Originally Posted by mike@x-ph.com

Whats your baseline?

Baseline?

I don't have one. First time on the dyno.

[mike@x-ph.com]

Originally Posted by Aramis1919

Baseline?

I don't have one. First time on the dyno.

Dynos are not meant to measure your absolute power. They are meant to measure the delta between one setup and the other. So, for example, if you add a mod, you can use the same dyno and measure how much power it added.

But you can't compare your numbers to a number posted by BMW or anyone else on a different dyno. Each dyno reads differently and your dyno might just read higher than other dynos

[JoeyJoeJo]

Nice results! 475lbft would be about 650NM so a chunky uplift, any concerns with a 30% hike there or are the transmission parts considered OK at that level?

Would have been interesting to see with/without the JB+

[Aramis1919]

Originally Posted by JoeyJoeJo

Nice results! 475lbft would be about 650NM so a chunky uplift, any concerns with a 30% hike there or are the transmission parts considered OK at that level?

Would have been interesting to see with/without the JB+

Without the JB+ the car took 10 seconds to reach 100MPH (according to Dragy)

Now, on a cool day, I'm looking at 8.4-8.8 seconds.

30-70 in 4th takes 4.5 secs with Dragy......a second longer without 5.5.

[Aramis1919]

Originally Posted by mike@x-ph.com

Dynos are not meant to measure your absolute power. They are meant to measure the delta between one setup and the other. So, for example, if you add a mod, you can use the same dyno and measure how much power it added.

But you can't compare your numbers to a number posted by BMW or anyone else on a different dyno. Each dyno reads differently and your dyno might just read higher than other dynos

All I can say is that these are the figures produced by mustang dyno on this specific day.

Other cars did not seem to produce 'higher than expected' power and torque figures. For example a Jaguar F-Type 5.0 SC struggled to make 550 BHP although it was rated t 567 BHP/575 PS.

[SeanJP]

Originally Posted by Aramis1919

All I can say is that these are the figures produced by mustang dyno on this specific day.

Other cars did not seem to produce 'higher than expected' power and torque figures. For example a Jaguar F-Type 5.0 SC struggled to make 550 BHP although it was rated t 567 BHP/575 PS.

If it's measuring that at the wheels, that's actually higher than expected. The rule of thumb is a 15% drivetrain loss, which is where you would be at he wheels. To convert it back, you would divide by 0.85.

So, for the Jaguar you would take 550 whp / 0.85 = 647 at the crank. That is substantially more than the factory rating.

For yours, 445 whp = 524 hp at the crank. Something is off.

[Aramis1919]

Originally Posted by SeanJP

If it's measuring that at the wheels, that's actually higher than expected. The rule of thumb is a 15% drivetrain loss, which is where you would be at he wheels. To convert it back, you would divide by 0.85.

So, for the Jaguar you would take 550 whp / 0.85 = 647 at the crank. That is substantially more than the factory rating.

For yours, 445 whp = 524 hp at the crank. Something is off.

I was informed that all figures were assumed at the crank by measuring WHP and then adding a 16% conversion factor.

My 445BHP figure is a crank figure.

[Aramis1919]

Originally Posted by Aramis1919

I was informed that all figures were assumed at the crank by measuring WHP and then adding a 16% conversion factor.

My 445BHP figure is a crank figure.

The 550BHP for the Jaaaggg is also a crank figure

[SeanJP]

Originally Posted by Aramis1919

I was informed that all figures were assumed at the crank by measuring WHP and then adding a 16% conversion factor.

My 445BHP figure is a crank figure.

That’s kind of an odd way for a shop to report their numbers. Usually they just give you the raw WHP numbers. Also, the general rule of thumb is 15% drivetrain loss, but of course that can be plus or minus depending on the car. I don’t know how they came up with 16%.

So if we go by that, that would mean you made 374 to the wheels. BMW notoriously sandbags their horsepower ratings, so that is entirely in line with what I would expect.

[Rdurty2]

Originally Posted by SeanJP

That’s kind of an odd way for a shop to report their numbers. Usually they just give you the raw WHP numbers. Also, the general rule of thumb is 15% drivetrain loss, but of course that can be plus or minus depending on the car. I don’t know how they came up with 16%.

So if we go by that, that would mean you made 374 to the wheels. BMW notoriously sandbags their horsepower ratings, so that is entirely in line with what I would expect.

Also keep in mind that his car isn’t stock, it has a jb+ which is probably good for around 20hp I’m guessing.

So no idea why it’s being compared to BMWs numbers.

[Aramis1919]

Well, she has posted 11.6 at almost 120 MPH at Santa Pod so must be making a good amount of horses.

Although all drag strips use 1 foot rollout as standard which is cheating a bit.