F80 M3 vs E92 M3 Dyno Numbers by Motortrend

[Dalko43]

Originally Posted by gthal

4) I think it is unrealistic for non-M3/4 owners to doubt dyno numbers and 1/4 mile trap speeds and pass them off as unbelievable simply because they don't have any euphoria for the car( see what I did there?). The reality is butt dynos are meaningless (yes, even from auto journalists) and dyno and trap speed evidence is far better than "I just don't believe it" evidence.

I don't doubt the 1/4 times. I know the M4 and C7 have comparable times and agree, as you said earlier, that comparing the 2 on this issue is mostly meaningless because traction is largely determining the results. The C7 lacks a DCT and seems to experience a lot more wheel spin and longer shift times than the M4. Thus the 1/4 times don't really do a good job of showing which car is faster.

I do doubt these other dyno tests because:
1) Motortrend did a test that showed contradictory results
2) I think it's unrealistic that BMW would've under rated their car by that much
3) I don't think that an auto journalist's butt dyno is the end-all-be-all determination of how much HP a car has...but with all the cars they test, they would certainly notice if a car had substantially more HP that what was claimed. So far none have commented on that.
4) the C7 is a bit faster around a track (according to the times put out so far).

My lack of a M4 has nothing to do with the 4 reasons stated above. For the record, I wish I had M4 euphoria too.

Originally Posted by gthal

Put another way, the M4 is NOT performing like a car down 35HP and up 100lbs on a C7 Z51. It is far too close in STRAIGHT LINE performance. We should also STOP debating how lap times plays any role in this discussion because there is far too much involved on a road course to draw any meaningful conclusions relative to power. If you don't understand that, than there is little point to debating this. So, when an M4 with more weight than a C7 traps similar or faster 1/4 mile speed, what is your explanation for the much lower "factory stated" HP? Dumb luck?

We've already discussed the reasons for the similar trap times between the 2 cars and why it's a meaningless comparison. The 911 carrera S, despite having less HP than both, has faster 0-60 and 1/4 mile times.

The lap times show how fast these cars are running down the straightaway (instead of from a dead stop). The braking is similar between the 2. Your assessment on the C7 having better handling is subjective and others seem to dispute it as shown by the video I posted previously. Though the C7 is 100lb's lighter, that's not enough to account for an over 1 sec difference on the Hockenheim.

Most things being equal, or at least comparable, between the 2 cars, the C7's higher HP is allowing it to put out faster lap times...so far. If the M4 truly had something north of 450HP, would that be the case?

[Dalko43]

Originally Posted by gthal

You are AWESOME!!!

So, again, you ignore any data that doesn't support your belief and pick one dyno of two cars on different days and say THAT dyno proves something but the others are all wrong.

Again, track times are not useful as there are too many factors that impact the result to conclude on HP... SO.... please explain how the M4 traps the same with 35 less HP and 100 lbs more weight? I'm not suggesting that the M4 is a 460 or 470hp car but I am suggesting it is nowhere near 425 given its ACTUAL performance. I will also agree there is more to the story than peak HP... what I'm really trying to do is ask you to respond to the other data points that you continue to ignore.

P.S. I think we need to see another video to resolve this debate

The tests were conducted on different days but on the same dyno facility using the same testing methods. The reason I emphasize that is because even if K&N's testing was flawed or somehow inaccurate, as many claim, it was flawed or inaccurate for both cars.

So in the same way that the HP and Tq differences can be demonstrated between the E9x M3 and the F8X M4, so too can they be demonstrated between the M4 and C7.

As for the cars being tested on different days, unless there was a drastic temperature difference (which it didn't look like there was), I don't see how the test results could have been affected differently on one day versus the other.

Everything else in your post was addressed above.

[gthal]

Originally Posted by Dalko43

I don't doubt the 1/4 times. I know the M4 and C7 have comparable times and agree, as you said earlier, that comparing the 2 on this issue is mostly meaningless because traction is largely determining the results. The C7 lacks a DCT and seems to experience a lot more wheel spin and longer shift times than the M4. Thus the 1/4 times don't really do a good job of showing which car is faster.
....

We've already discussed the reasons for the similar trap times between the 2 cars and why it's a meaningless comparison. The 911 carrera S, despite having less HP than both, has faster 0-60 and 1/4 mile times.

Just to be clear, I said track comparisons were meaningless. 1/4 mile trap speeds are NOT meaningless.

A couple of comments... the auto in the C7 is fast shifting and would not meaningfully impact the car's trap speed. The same thing with traction... some of the 60' times, etc for the C7 have been very impressive. Also, the C7 auto has been faster than the 911S in most tests. The 911S weighs SO much less than both the M4 and C7 that its speed is impacted by this regardless of its HP.

In any event, this debate is academic at this point and it has already been beaten to death here in several threads. I believe the general consensus (although I may be wrong) is not in agreement with you and that would include people who are far brighter and informed than I am. You can believe what you want and so will I.

Just for the record, I don't really care about HP and straight line speed other than for interest sake. I'm a road course kind of person. My perspective in this debate is not from M4 euphoria but, rather, just my interpretation of a lot of data. I believe you are discounting information, making justifications and interpreting things based on you not being able to believe what you see... I could be wrong but that's my personal view. Let's agree to disagree on this one.

[jc05e46m3]

Originally Posted by gthal

True statement. IMO, the C7 and M4 have very similar power at the crank and the reason the C7 may prove very slightly faster in a straight line is lower weight and more rear tire. Having said that, the M4 has, in fact, been testing slightly faster in many tests which surprises me which suggests its stated HP rating is WAY off.

Agreed. The weight difference is substantial.

Originally Posted by Dalko43

I have a hard time believing this. Because Motortrend, a respected auto magazine, posted 2 separate videos where both the M4 and the C7 were dyno tested on the same K&N facility, the one that many people on this forum believe is consistently under rating the cars, or at the very least is inaccurate.

The results:
The M4 tested out at 376HP at the wheels.
The C7 tested out at 402HP at the wheels.

With a 15% powertrain loss accounted for, both results indicate crank HP numbers that more closely resemble what is claimed by both manufacturers. At the very least, the test results show that the C7 has substantially more HP at the crank than the M4.

Read on the C7 forums. Many people are not breaking into the 400 whp club.

[Dalko43]

Originally Posted by gthal

Just to be clear, I said track comparisons were meaningless. 1/4 mile trap speeds are NOT meaningless.

You also said 0-60 times were meaningless. I interpreted that to include 1/4 times, and if I assumed too much, I apologize.

Originally Posted by gthal

A couple of comments... the auto in the C7 is fast shifting and would not meaningfully impact the car's trap speed. The same thing with traction... some of the 60' times, etc for the C7 have been very impressive. Also, the C7 auto has been faster than the 911S in most tests. The 911S weighs SO much less than both the M4 and C7 that its speed is impacted by this regardless of its HP.

C7 auto is no doubt a faster shifter, but still not as fast as a DCT. The lack of that DCT, which not only contributes to slower shift times and more wheel slip off the start, is a big reason for why the C7's average 1/4 mile times/speeds resemble the M4's. With a manual transmission, there is a lot more room for user error...so some will put out times similar to the M4 and some will be a bit faster, something you acknowledged on another thread:

Originally Posted by gthal

Look up member Snorman on Corvette Forum. He has a slip showing 11.6. Another member has one at 11.8. Corvette Forum has a fast list with several members getting into the 11s.

Also, the 911 carrera s is only shy of the C7's weight by 150lb's or so. Weight savings help the 911 attain faster 0-60 and 1/4 mile times, but that's only partly responsible. That car has one of the fastest DCT's on the market and one of the best traction management systems.

Originally Posted by gthal

Just for the record, I don't really care about HP and straight line speed other than for interest sake. I'm a road course kind of person. My perspective in this debate is not from M4 euphoria but, rather, just my interpretation of a lot of data. I believe you are discounting information, making justifications and interpreting things based on you not being able to believe what you see... I could be wrong but that's my personal view. Let's agree to disagree on this one.

I think dyno tests in general are over emphasized and are prone to inaccurate readings and greatly vary from one dyno to another. Determining a car's true HP at the crank based on machine-read whp is an educated guess. I think there are a lot of people on this forum who are taking these educated guesses and passing them off as fact. I don't agree with that. The best info we can derive from a dyno is comparing one car's results to another's on the same dyno to demonstrate HP/Tq deltas.

I have a hard time believing that the M4 has +450HP at the crank because:
1) C7, a car of comparable weight, pulls faster 1/4 times, with a manual.
2) C7, a car of comparable, if not slightly worse, handling and braking, pulls a faster lap time.
3) C7, a car with 460HP at the crank, puts out a higher HP/tq result on the same K&N dyno facility.

I know that BMW under rates their cars and truly don't care how much HP the M4 has...I just think people are over exaggerating this car's HP capability and are ignoring the real world evidence which shows that.

Originally Posted by jc05e46m3

Read on the C7 forums. Many people are not breaking into the 400 whp club.

I think you need to reread the C7 forums and my earlier posts. Though there are varying results among the dyno tests, as is the norm, there are quite a few that show +400hp at the wheels of the C7:
http://www.corvette7.com/forums/showthread.php?t=329056
http://www.lingenfelter.com/LPEforum...sis-Dyno-Video
http://www.stingrayforums.com/forum/...t-results.html

Also, as I said above, dyno tests in and of themselves don't mean a whole lot..it's only when you test 2 cars on the same dyno facility that you get something useful, like Motortrend did with the C7 and M4 at K&N.

[jc05e46m3]

Originally Posted by Dalko43

I have a hard time believing that the M4 has +450HP at the crank because:
1) C7, a car of comparable weight, pulls faster 1/4 times, with a manual.
2) C7, a car of comparable, if not slightly worse, handling and braking, pulls a faster lap time.
3) C7, a car with 460HP at the crank, puts out a higher HP/tq result on the same K&N dyno facility.

I know that BMW under rates their cars and truly don't care how much HP the M4 has...I just think people are over exaggerating this car's HP capability and are ignoring the real world evidence which shows that.



I think you need to reread the C7 forums and my earlier posts. Though there are varying results among the dyno tests, as is the norm, there are quite a few that show +400hp at the wheels of the C7:
http://www.corvette7.com/forums/showthread.php?t=329056
http://www.lingenfelter.com/LPEforum...sis-Dyno-Video
http://www.stingrayforums.com/forum/...t-results.html

Also, as I said above, dyno tests in and of themselves don't mean a whole lot..it's only when you test 2 cars on the same dyno facility that you get something useful, like Motortrend did with the C7 and M4 at K&N.

I said MANY are not reaching the 400 wheel club and that's a fact. I don't need to re-read. The guys who are the average Joe's (not manufacturers or magazines) in the very very high majority are only getting in the 385-395 range. And I have personally seen two make less than that (but keep in mind I am on California 91 (as were the S55 powered cars out here) versus say the Kooks 93 octane baseline.

You're absolutely right, dynos dont matter unless done at the same location and same settings back to back (generally speaking), but I do truly believe the S55 is making more WHP/WTQ.

Where I would disagree is the weights. The vette is much lighter than the M3/M4 (and that's where I think the majority of the performance advantage is coming from, not to mention that big ass rear end)

The stingray is a beast and a better track car IMO, but thats another topic.

[Dalko43]

Originally Posted by jc05e46m3

You're absolutely right, dynos dont matter unless done at the same location and same settings back to back (generally speaking), but I do truly believe the S55 is making more WHP/WTQ.

Where I would disagree is the weights. The vette is much lighter than the M3/M4 (and that's where I think the majority of the performance advantage is coming from, not to mention that big ass rear end)

Okay, I guess we'll disagree on that. Motortrend's K&N dyno testing shows the vette getting substantially more HP/tq (not same day tests, but same testing methods). Also the Z51 vette is only about 100lb's lighter...there is some performance advantage there, but not much.

Also, do you have threads/links to demonstrate what you said below:

Originally Posted by jc05e46m3

I said MANY are not reaching the 400 wheel club and that's a fact. I don't need to re-read. The guys who are the average Joe's (not manufacturers or magazines) in the very very high majority are only getting in the 385-395 range.

[jc05e46m3]

Originally Posted by Dalko43

Okay, I guess we'll disagree on that. Motortrend's K&N dyno testing shows the vette getting substantially more HP/tq (not same day tests, but same testing methods). Also the Z51 vette is only about 100lb's lighter...there is some performance advantage there, but not much.

Also, do you have threads/links to demonstrate what you said below:

After further browsing of the C7 forums looks like many people are hitting that 400whp mark (though not a single one I've seen are like my friends here in SoCal who aren't getting there on 91). You were right and I stand corrected.

As far as weight, I didn't realize you had specified the Z51. I know base model to base model, the C7 is a good bit lighter.

[Mik3ymomo]

I prefer track results. A dyno is good for comparing a before and after or comparing 2 cars on the same day back to back under the same conditions. The numbers themselves are mostly irrelevant but the disparity between them is as accurate as you will be able to measure without pulling the motors and using engine dynos.

As far as comparing the weight vs HP of the cars and determining something from the comparison. Well at the drag strip traction and gearing play a role. It's not so much how fast the shifting as the differential and transmission gearing matched ideally to the engines power curve.

Try not to look solely at peak HP numbers. How fast a car is isn't about just its peak numbers. It's more about the curve before and after. The cars will only be at their peak numbers for a moment.
Think of the power through the entire rpm range. Look at where the shift points are and how long it takes to first get to its ideal power range and how long it can stay in that range. It's the reason we have 7 and 8 speed transmissions now. The closer the gears are the better the trans can keep the engine in its ideal power range.

Also how much parasitic drag does one driveline have vs the other...Weight, design etc all play a part. Overall weight is part of the equation but how much of the Vettes weight is unsprung vs that of the M3.
We don't have enough data to make exact comparisons on the chassis.

Both cars you are comparing have strengths, both make power and transfer it differently but both are Fantastic platforms.

I would expect the Vette to be faster on a race track for a couple of reasons. First its got a lot of tire under it. But besides how fast it is in the turns it can exit the turns with zero lag and a lot of low end torque. Torque is what moves you. Look at HP as more of the potential for higher speeds but torque is what you feel in the seat of your pants and snaps your neck when you accelerate.

Also FI cars heat soak on a road course and as someone mentioned the heat on the turbo car will slow it down.

I enjoy the discussion. I don't think anyone here is stating untruths about the how and why. There is just some lack of experience here on general understandings of why one car is faster then another. While these ARE factors; it comes down to more then curb weights and trap speeds or dyno sheets.

[Elijaih]

Originally Posted by Dalko43

I have a hard time believing this. Because Motortrend, a respected auto magazine, posted 2 separate videos where both the M4 and the C7 were dyno tested on the same K&N facility, the one that many people on this forum believe is consistently under rating the cars, or at the very least is inaccurate.

The results:
The M4 tested out at 376HP at the wheels.
The C7 tested out at 402HP at the wheels.

With a 15% powertrain loss accounted for, both results indicate crank HP numbers that more closely resemble what is claimed by both manufacturers. At the very least, the test results show that the C7 has substantially more HP at the crank than the M4.

Did anyone else notice that the front wheels are not spinning on the C7 dyno and that the front wheels are spinning for the M4 and M3 dyno? Look at the 3:40 mark on the C7 video, it isn't a great angle, but the only one I could find on that video that shows a front wheel. I watched it multiple times and the front wheel isn't spinning. On the M4 and M3 dyno, you can see the front wheels spinning a few times.

Would that mean the dyno was set to AWD for the M4 and M3, hence low numbers for both the M4 and M3? The C7 dyno was set to RWD so more accurate to what it should be.

[CanAutM3]

Originally Posted by Elijaih

Did anyone else notice that the front wheels are not spinning on the C7 dyno and that the front wheels are spinning for the M4 and M3 dyno? Look at the 3:40 mark on the C7 video, it isn't a great angle, but the only one I could find on that video that shows a front wheel. I watched it multiple times and the front wheel isn't spinning. On the M4 and M3 dyno, you can see the front wheels spinning a few times.

Would that mean the dyno was set to AWD for the M4 and M3, hence low numbers for both the M4 and M3? The C7 dyno was set to RWD so more accurate to what it should be.

Good catch. I was about to post this myself, but you beat me to it.

As I posted several time in this thread, since the E92 M3 and F80 M3 were tested with all four wheel rollers interconnected significantly increased the losses and inertial impacts, thus lower WHP numbers.

Since the C7 was tested with only two rollers running, it suffered less loss.

[CanAutM3]

Originally Posted by Dalko43

I have a hard time believing this. Because Motortrend, a respected auto magazine, posted 2 separate videos where both the M4 and the C7 were dyno tested on the same K&N facility, the one that many people on this forum believe is consistently under rating the cars, or at the very least is inaccurate.

The results:
The M4 tested out at 376HP at the wheels.
The C7 tested out at 402HP at the wheels.

With a 15% powertrain loss accounted for, both results indicate crank HP numbers that more closely resemble what is claimed by both manufacturers. At the very least, the test results show that the C7 has substantially more HP at the crank than the M4.

Maybe the same dyno, but not same setup.

The dyno run for the C7 was done in 2WD mode. Lower losses and inertial impacts, hence higher reading.

[gxman]

I remember one of the videos saying they have to spin the front wheels b/c the car is programmed to not run after a certain mph if the front wheels arent spinning.

[CanAutM3]

Originally Posted by gxman

I remember one of the videos saying they have to spin the front wheels b/c the car is programmed to not run after a certain mph if the front wheels arent spinning.

That was in the M5 vs E63 Motortrend video.

There are example of E9X M3s and F8X running on dynos with only the rear wheel turning though...

[Dalko43]

Originally Posted by Mik3ymomo

I prefer track results. A dyno is good for comparing a before and after or comparing 2 cars on the same day back to back under the same conditions. The numbers themselves are mostly irrelevant but the disparity between them is as accurate as you will be able to measure without pulling the motors and using engine dynos.

That's exactly what I was saying in my earlier posts...so it's refreshing to see someone who agrees with that.

Originally Posted by Mik3ymomo

As far as comparing the weight vs HP of the cars and determining something from the comparison. Well at the drag strip traction and gearing play a role. It's not so much how fast the shifting as the differential and transmission gearing matched ideally to the engines power curve.

Try not to look solely at peak HP numbers. How fast a car is isn't about just its peak numbers. It's more about the curve before and after. The cars will only be at their peak numbers for a moment.
Think of the power through the entire rpm range. Look at where the shift points are and how long it takes to first get to its ideal power range and how long it can stay in that range. It's the reason we have 7 and 8 speed transmissions now. The closer the gears are the better the trans can keep the engine in its ideal power range.

Also how much parasitic drag does one driveline have vs the other...Weight, design etc all play a part. Overall weight is part of the equation but how much of the Vettes weight is unsprung vs that of the M3.
We don't have enough data to make exact comparisons on the chassis.

All very valid points. I realize my earlier discussion of the M4 vs C7 was overly simplistic. Gearing, unsprung weight, area under the power curve...all things that will influence how a car performs.

The only reason I didn't include those aspects of car performance is because I was trying to focus in on how the C7 is not only faster than the M4 but also has more HP....something more than a few people on this forum refuse to acknowledge.

Originally Posted by CanAutM3

Maybe the same dyno, but not same setup.

The dyno run for the C7 was done in 2WD mode. Lower losses and inertial impacts, hence higher reading.

I am not going to claim to be a dyno expert...so I don't really know if the C7's dyno test had lower losses or not...I'll take your word on it for the time being.

But anyone who thinks that the M4 truly has more or comparable HP to the c7, and there are a few on this forum, is living in a fantasy land. That was really my only reason for bringing up the two Motortrend dyno tests.