[ZombiePhysicist]

Um, OK. Maybe measure for the body weight of the engine designer?

Well, the total engine weights (current working numbers) of the V12s in the T.50 and the T.50s are 178 kg and 162 kg, respectively. In both these cars, the engine is semi-structrual.

You should research the weights of the other engines.

I vaguely remember a Cherolet engineer saying that the LT6 is "only 1 kg more" than an LT2 engine. I also vaguely remember that the total weight of an LT2 is ~475 lb (~215 kg). If my recollections are correct, we have 725 PS / 162 kg (T.50s), 700 PS / 178 kg (T.50), and 679 PS / 216 kg (Corvette), or ~4.475, ~4.069, and ~3.143, respectively. With this (rather arbitrary) metric, the "density" of the T.50 road car's engine output is ~30% better than the Corvette's. That's almost the same difference as with the "power per liter" metric.

Unfortunately, I do not know the body weights of various engine designers.

Thanks for the facetious opener, then admission via dive in actual weights, because yea, weight/density all matter. It's why it's the measure wrt to electric vehicles. Power density matters a lot. Which is totally impressive on both per liter and and overall weight/size/density re the T50 engine.

I was under the apparently completely wrong impression that the C8z engine was about the same 'size' as the T50 engine (in rough weight/bulk). If basically the T50 V12 engine is 30% lighter/less bulky than the C8z v8, that's super cool and super impressive!

Thanks.

 

[ZombiePhysicist]

Um, OK. Maybe measure for the body weight of the engine designer?

Well, the total engine weights (current working numbers) of the V12s in the T.50 and the T.50s are 178 kg and 162 kg, respectively. In both these cars, the engine is semi-structrual.

You should research the weights of the other engines.

I vaguely remember a Cherolet engineer saying that the LT6 is "only 1 kg more" than an LT2 engine. I also vaguely remember that the total weight of an LT2 is ~475 lb (~215 kg). If my recollections are correct, we have 725 PS / 162 kg (T.50s), 700 PS / 178 kg (T.50), and 679 PS / 216 kg (Corvette), or ~4.475, ~4.069, and ~3.143, respectively. With this (rather arbitrary) metric, the "density" of the T.50 road car's engine output is ~30% better than the Corvette's. That's almost the same difference as with the "power per liter" metric.

Unfortunately, I do not know the body weights of various engine designers.

Although I'm noticing youre using the output of the T50s. The T50S is about 30% more, the 'regular' T50 engine is about 23%, which, still is very impressive.

 

[iohead]

Although I'm noticing youre using the output of the T50s. The T50S is about 30% more, the 'regular' T50 engine is about 23%, which, still is very impressive.

I just wanted to make sure that you calculate for yourself

But yes, for the T.50 road car, 700 PS / 178 kg = 3.932 PS / kg. For the Corvette, it's 679 PS / 216 kg = 3.143 PS / kg. Therefore:

(3.932 - 3.143) / 3.143 =~ 25%

The same calculation for the T.50s gives 725[*] PS / 162 kg = 4.475 PS / kg. Therefore:

(4.475 - 3.143) / 3.143 =~ 42%

[*] The final power output of the T.50s engine could be materially higher than this.

Do you concur on the math?

(Much more appealing than Lamborghini's spiel about the supercapacitor in the similarly priced Sián and the new "Countach", where the extra 35 PS costs 35 kg in weight.)

 

[Mikeyb]

@aorta Think Valkyrie is turbo motor?

no its NA, with small hybrid for torque fill low down..

 

[Jonathan19]

 

[ZombiePhysicist]

I just wanted to make sure that you calculate for yourself

But yes, for the T.50 road car, 700 PS / 178 kg = 3.932 PS / kg. For the Corvette, it's 679 PS / 216 kg = 3.143 PS / kg. Therefore:

(3.932 - 3.143) / 3.143 =~ 25%

The same calculation for the T.50s gives 725[*] PS / 162 kg = 4.475 PS / kg. Therefore:

(4.475 - 3.143) / 3.143 =~ 42%

[*] The final power output of the T.50s engine could be materially higher than this.

Do you concur on the math?

(Much more appealing than Lamborghini's spiel about the supercapacitor in the similarly priced Sián and the new "Countach", where the extra 35 PS costs 35 kg in weight.)

I was just doing the simple (3.932/3.143)-1 ~25% and ((4.475/3.143)-1) ~42% (unfortunately I was guesstimating in my head, lazily, rather than putting it into the calculator so my numbers came out wrong).

So yes, I concur. And the difference is super. Again, I was working on the apparently wrong impression that the C8Z and t50 engines were about the same size. And apparently, the T50 engine is TINY! So it is a super impressive dense power pack.

 

[invisiblewave]

I was just doing the simple (3.932/3.143)-1 ~25% and ((4.475/3.143)-1) ~42% (unfortunately I was guesstimating in my head, lazily, rather than putting it into the calculator so my numbers came out wrong).

So yes, I concur. And the difference is super. Again, I was working on the apparently wrong impression that the C8Z and t50 engines were about the same size. And apparently, the T50 engine is TINY! So it is a super impressive dense power pack.

Holy crap! No wonder you're now a zombie physicist! How many brain cells died in the course of this thread???

 

[ZombiePhysicist]

Holy crap! No wonder you're now a zombie physicist! How many brain cells died in the course of this thread???

Your deep analysis of "this sucks and is stupid, stop talking on a discussion forum' was a huge value add in contrast. .

Dude, no one is making you read any of it or my posts. Feel free to hit ignore if it bothers you so much.

 

[Zeus]

The discussion and comparison of engines, the very heart of any car & in the hearts of true car enthusiasm, is the very essence of this hobby.

I tell my wife every day - I get up every morning in a pretty good mood, and then...people.

 

[TougeSpirit]

Not to mention, because the V12 is semi structural, it saves probably another 10+ kg off the chassis. And we haven't even talked about CG, of which Gordon pushed Cosworth on for crank height. Or throttle response, which is really underrated in this recent discussion. If I recall the calculations, this car can light up the tires all the way through third gear.

The intake system of the C8Z engine is super complex and large in size. That engine barely fits in the Z06. It wouldn't come close to fitting in the T.50. not to mention I think GM made the decision to have camshaft mounted finger followers which are debatable on if that will truly be no adjustment for lifetime of the engine, along with the belt and pulleys vs Cosworth gear driven

Ironically in this discussion. The old LT4 makes more torque and slightly less power than the LT6. and the same argument regarding gearing applies here too between the Vette engines

 

[rnixon]

It wouldn't come close to fitting in the T.50. not to mention I think GM made the decision to have camshaft mounted finger followers which are debatable on if that will truly be no adjustment for lifetime of the engine, along with the belt and pulleys vs Cosworth gear driven

GM is ambiguous in this context

 

[sailfly]

Interesting video

 

[TougeSpirit]

The loads they're designing the diffuser to are very interesting. And the tunnels look more aggressive than I thought

 

[Jonathan19]

 

[Jonathan19]

Love this one!

 

[Bridster]

An interesting engine debate!

Just to touch on the torque vs power point - which I don't think people sufficiently understand:

The first thing you need to realize (and surprisingly few people realize it even though it's fairly obvious) is that cars will have more torque in lower gears than in higher gears. The reason car acceleration gets slower as you go up with speed isn't primarily because of air resistance, but because you are trading torque for the ability to reach higher speeds. The T.50, for example, puts down roughly only 1/4th the torque in 6th gear that it does in 1st gear (and this is almost the same for all cars).

Next thing you need to know is that Power = Torque x RPM.

Now that we know that, let's imagine two engines that both make the same power. One engine will be like the T.50's engine, rev to 12k RPM and make 470Nm of torque. The other engine will be turbocharged and rev to 6k. Since it needs to make the same power with only half the revs, it means it will have twice the torque: 940Nm.

So, will this monster torque have any effect on the performance? None whatsoever. Why is that? Well, let's look at the gearing. For the sake of simplicity, let's say the 1st gear ratio is 3:1 and the final drive is 4:1, for the final torque multiplication of 12:1. Let's also say that taking wheel diameter into account, this allows for 60mph top speed in 1st gear.

The way this works out for the 12k RPM engine is that when it's at 12k RPM, the wheels rotate at 1k RPM. It also means that the torque at the wheels is 12x! That would be 5640Nm in 1st gear.

If we use the same gearing for the 6k RPM engine, what you'll find is while the torque is still multiplied 12x and it makes 11280Nm, when the engine reaches 6k RPM, the wheels rotate only at 500RPM - and so it can only reach 30mph! So in this case what you need to do is change the final drive ratio from 4:1 to 2:1. That way you can reach the same speed, but at the same time it halves the torque.

So, predictably, the final torque at the wheels is identical for both engines! It doesn't really matter whether the engine makes "paltry" 467Nm of torque, or 1000Nm of torque, or 3000Nm of torque because it's an industrial diesel. Power is what matters. Saying that one car will be faster because it has more torque makes exactly as much sense as saying that one car will be faster because it can rev higher!

---

HOWEVER... A completely different discussion is about how the torque curve looks like and what effect that has on acceleration (and usability). This is looking at what percentage of the peak torque you can get at any given engine speed - and because we are looking at percentages, it makes absolutely no difference what the peak value is.

The general perception is that engines that rev higher will have a torque curve that's very weak at low revs and will only really get going at higher revs. While there would probably be a correlation, this is not necessarily true! One example, the screaming V8 in the 458 Speciale that revs to 9k RPM has higher low down torque than the supercharged push-rod V8 in the C7 Z06 Corvette!

How does the T.50's V12 stack up? Well, let's set up a little test. What do you need low down torque for? Probably for something like driving down a highway at 70mph in 6th gear and wanting to accelerate as fast as possible without needing to shift down, right? Ok, let's look at that.

In the T.50, in 6th gear doing 70mph, you'll be at 3487RPM. Now, we don't have a full torque curve yet for the T.50, so here comes a bit of guesswork, but we know that it makes 71% of torque at 2500RPM. That's actually the same as the 991.2 GT3RS, so let's use that torque curve for now. Following that, at 3500RPM the engine will be producing about 78% of its peak torque.

In the 458 Speciale, in 7th at 70mph you'll be at 2922RPM, making 79% of peak torque. In the C7 Z06 Corvette, you'll be at 1514RPM, making 73% of peak torque.

So there you go, the T.50 actually makes higher percentage of peak torque in that situation than the supercharged Corvette, which makes 881Nm (and almost similar power at 659PS). And, even if it didn't, there is still the fact that the T.50 is 550kg lighter than the Corvette, so even if the Corvette was at 100% of peak torque, the T.50 would still leave it in the dust, even with both cars in 6th gear at low engine speed. I wouldn't really worry about T.50's ability to accelerate, no matter the circumstance. It's gonna be frighteningly fast and powerful enough to be tire limited in 1st, 2nd and maybe even 3rd gear if the conditions are not perfect!

---

Lastly, and sorry for the long post, about the T.50's engine compared to the C8 Z06 one. Objectively, there is really no comparison. The T.50's engine is lighter (178kg vs 212kg), smaller, makes more power per kg (3.72 vs 3.21), more power per liter (166 vs 124), more torque per liter (116.8 vs 113.5) and revs much higher. The revs, as you might have learned, are not there just for show or for noise, but more revs mean more power! That's how the power per kg and per liter gets so high - and why F1 engines rev as high as possible!

The T.50's engine is also much more advanced. It uses Metal Matrix Composite pistons - which is a first on a road car. It has a VVT system that's able to work at 12k RPM (that was one of the big challenges and why you haven't seen any engines reach 12k up until now) and loads of other trick stuff to make the high redline possible. It has plasma sprayed iron coated cylinder walls, CNC machined crankshaft, only 85mm crank height (115mm on the SF90, for example), triple vacuum remelted springs, etc. It also has more torque per liter which means they are able to get more work out of the combustion.

The Corvette engine is great and I am very happy that they decided to make it, but technically it doesn't seem to be any better than the Ferrari 458 engine and actually it's worse in some aspects. Maybe it's not completely fair to compare it to an engine from more than 10 years ago because of changing emission regs that make creating power more difficult, but it probably wouldn't be completely unfair to say that the Corvette engine is where Ferrari was 10 years ago. The Cosworth engine is where NA engines could have been if the development didn't stop and go towards turbos. Now let's just hope it's reliable .

 

[invisiblewave]

An interesting engine debate!

Just to touch on the torque vs power point - which I don't think people sufficiently understand:

The first thing you need to realize (and surprisingly few people realize it even though it's fairly obvious) is that cars will have more torque in lower gears than in higher gears. The reason car acceleration gets slower as you go up with speed isn't primarily because of air resistance, but because you are trading torque for the ability to reach higher speeds. The T.50, for example, puts down roughly only 1/4th the torque in 6th gear that it does in 1st gear (and this is almost the same for all cars).

Next thing you need to know is that Power = Torque x RPM.

Now that we know that, let's imagine two engines that both make the same power. One engine will be like the T.50's engine, rev to 12k RPM and make 470Nm of torque. The other engine will be turbocharged and rev to 6k. Since it needs to make the same power with only half the revs, it means it will have twice the torque: 940Nm.

So, will this monster torque have any effect on the performance? None whatsoever. Why is that? Well, let's look at the gearing. For the sake of simplicity, let's say the 1st gear ratio is 3:1 and the final drive is 4:1, for the final torque multiplication of 12:1. Let's also say that taking wheel diameter into account, this allows for 60mph top speed in 1st gear.

The way this works out for the 12k RPM engine is that when it's at 12k RPM, the wheels rotate at 1k RPM. It also means that the torque at the wheels is 12x! That would be 5640Nm in 1st gear.

If we use the same gearing for the 6k RPM engine, what you'll find is while the torque is still multiplied 12x and it makes 11280Nm, when the engine reaches 6k RPM, the wheels rotate only at 500RPM - and so it can only reach 30mph! So in this case what you need to do is change the final drive ratio from 4:1 to 2:1. That way you can reach the same speed, but at the same time it halves the torque.

So, predictably, the final torque at the wheels is identical for both engines! It doesn't really matter whether the engine makes "paltry" 467Nm of torque, or 1000Nm of torque, or 3000Nm of torque because it's an industrial diesel. Power is what matters. Saying that one car will be faster because it has more torque makes exactly as much sense as saying that one car will be faster because it can rev higher!

---

HOWEVER... A completely different discussion is about how the torque curve looks like and what effect that has on acceleration (and usability). This is looking at what percentage of the peak torque you can get at any given engine speed - and because we are looking at percentages, it makes absolutely no difference what the peak value is.

The general perception is that engines that rev higher will have a torque curve that's very weak at low revs and will only really get going at higher revs. While there would probably be a correlation, this is not necessarily true! One example, the screaming V8 in the 458 Speciale that revs to 9k RPM has higher low down torque than the supercharged push-rod V8 in the C7 Z06 Corvette!

How does the T.50's V12 stack up? Well, let's set up a little test. What do you need low down torque for? Probably for something like driving down a highway at 70mph in 6th gear and wanting to accelerate as fast as possible without needing to shift down, right? Ok, let's look at that.

In the T.50, in 6th gear doing 70mph, you'll be at 3487RPM. Now, we don't have a full torque curve yet for the T.50, so here comes a bit of guesswork, but we know that it makes 71% of torque at 2500RPM. That's actually the same as the 991.2 GT3RS, so let's use that torque curve for now. Following that, at 3500RPM the engine will be producing about 78% of its peak torque.

In the 458 Speciale, in 7th at 70mph you'll be at 2922RPM, making 79% of peak torque. In the C7 Z06 Corvette, you'll be at 1514RPM, making 73% of peak torque.

So there you go, the T.50 actually makes higher percentage of peak torque in that situation than the supercharged Corvette, which makes 881Nm (and almost similar power at 659PS). And, even if it didn't, there is still the fact that the T.50 is 550kg lighter than the Corvette, so even if the Corvette was at 100% of peak torque, the T.50 would still leave it in the dust, even with both cars in 6th gear at low engine speed. I wouldn't really worry about T.50's ability to accelerate, no matter the circumstance. It's gonna be frighteningly fast and powerful enough to be tire limited in 1st, 2nd and maybe even 3rd gear if the conditions are not perfect!

---

Lastly, and sorry for the long post, about the T.50's engine compared to the C8 Z06 one. Objectively, there is really no comparison. The T.50's engine is lighter (178kg vs 212kg), smaller, makes more power per kg (3.72 vs 3.21), more power per liter (166 vs 124), more torque per liter (116.8 vs 113.5) and revs much higher. The revs, as you might have learned, are not there just for show or for noise, but more revs mean more power! That's how the power per kg and per liter gets so high - and why F1 engines rev as high as possible!

The T.50's engine is also much more advanced. It uses Metal Matrix Composite pistons - which is a first on a road car. It has a VVT system that's able to work at 12k RPM (that was one of the big challenges and why you haven't seen any engines reach 12k up until now) and loads of other trick stuff to make the high redline possible. It has plasma sprayed iron coated cylinder walls, CNC machined crankshaft, only 85mm crank height (115mm on the SF90, for example), triple vacuum remelted springs, etc. It also has more torque per liter which means they are able to get more work out of the combustion.

The Corvette engine is great and I am very happy that they decided to make it, but technically it doesn't seem to be any better than the Ferrari 458 engine and actually it's worse in some aspects. Maybe it's not completely fair to compare it to an engine from more than 10 years ago because of changing emission regs that make creating power more difficult, but it probably wouldn't be completely unfair to say that the Corvette engine is where Ferrari was 10 years ago. The Cosworth engine is where NA engines could have been if the development didn't stop and go towards turbos. Now let's just hope it's reliable .

Tremendous.

 

[rnixon]

An interesting engine debate!

Just to touch on the torque vs power point - which I don't think people sufficiently understand:

The first thing you need to realize (and surprisingly few people realize it even though it's fairly obvious) is that cars will have more torque in lower gears than in higher gears. The reason car acceleration gets slower as you go up with speed isn't primarily because of air resistance, but because you are trading torque for the ability to reach higher speeds. The T.50, for example, puts down roughly only 1/4th the torque in 6th gear that it does in 1st gear (and this is almost the same for all cars).

Next thing you need to know is that Power = Torque x RPM.

Now that we know that, let's imagine two engines that both make the same power. One engine will be like the T.50's engine, rev to 12k RPM and make 470Nm of torque. The other engine will be turbocharged and rev to 6k. Since it needs to make the same power with only half the revs, it means it will have twice the torque: 940Nm.

So, will this monster torque have any effect on the performance? None whatsoever. Why is that? Well, let's look at the gearing. For the sake of simplicity, let's say the 1st gear ratio is 3:1 and the final drive is 4:1, for the final torque multiplication of 12:1. Let's also say that taking wheel diameter into account, this allows for 60mph top speed in 1st gear.

The way this works out for the 12k RPM engine is that when it's at 12k RPM, the wheels rotate at 1k RPM. It also means that the torque at the wheels is 12x! That would be 5640Nm in 1st gear.

If we use the same gearing for the 6k RPM engine, what you'll find is while the torque is still multiplied 12x and it makes 11280Nm, when the engine reaches 6k RPM, the wheels rotate only at 500RPM - and so it can only reach 30mph! So in this case what you need to do is change the final drive ratio from 4:1 to 2:1. That way you can reach the same speed, but at the same time it halves the torque.

So, predictably, the final torque at the wheels is identical for both engines! It doesn't really matter whether the engine makes "paltry" 467Nm of torque, or 1000Nm of torque, or 3000Nm of torque because it's an industrial diesel. Power is what matters. Saying that one car will be faster because it has more torque makes exactly as much sense as saying that one car will be faster because it can rev higher!

---

HOWEVER... A completely different discussion is about how the torque curve looks like and what effect that has on acceleration (and usability). This is looking at what percentage of the peak torque you can get at any given engine speed - and because we are looking at percentages, it makes absolutely no difference what the peak value is.

The general perception is that engines that rev higher will have a torque curve that's very weak at low revs and will only really get going at higher revs. While there would probably be a correlation, this is not necessarily true! One example, the screaming V8 in the 458 Speciale that revs to 9k RPM has higher low down torque than the supercharged push-rod V8 in the C7 Z06 Corvette!

How does the T.50's V12 stack up? Well, let's set up a little test. What do you need low down torque for? Probably for something like driving down a highway at 70mph in 6th gear and wanting to accelerate as fast as possible without needing to shift down, right? Ok, let's look at that.

In the T.50, in 6th gear doing 70mph, you'll be at 3487RPM. Now, we don't have a full torque curve yet for the T.50, so here comes a bit of guesswork, but we know that it makes 71% of torque at 2500RPM. That's actually the same as the 991.2 GT3RS, so let's use that torque curve for now. Following that, at 3500RPM the engine will be producing about 78% of its peak torque.

In the 458 Speciale, in 7th at 70mph you'll be at 2922RPM, making 79% of peak torque. In the C7 Z06 Corvette, you'll be at 1514RPM, making 73% of peak torque.

So there you go, the T.50 actually makes higher percentage of peak torque in that situation than the supercharged Corvette, which makes 881Nm (and almost similar power at 659PS). And, even if it didn't, there is still the fact that the T.50 is 550kg lighter than the Corvette, so even if the Corvette was at 100% of peak torque, the T.50 would still leave it in the dust, even with both cars in 6th gear at low engine speed. I wouldn't really worry about T.50's ability to accelerate, no matter the circumstance. It's gonna be frighteningly fast and powerful enough to be tire limited in 1st, 2nd and maybe even 3rd gear if the conditions are not perfect!

---

Lastly, and sorry for the long post, about the T.50's engine compared to the C8 Z06 one. Objectively, there is really no comparison. The T.50's engine is lighter (178kg vs 212kg), smaller, makes more power per kg (3.72 vs 3.21), more power per liter (166 vs 124), more torque per liter (116.8 vs 113.5) and revs much higher. The revs, as you might have learned, are not there just for show or for noise, but more revs mean more power! That's how the power per kg and per liter gets so high - and why F1 engines rev as high as possible!

The T.50's engine is also much more advanced. It uses Metal Matrix Composite pistons - which is a first on a road car. It has a VVT system that's able to work at 12k RPM (that was one of the big challenges and why you haven't seen any engines reach 12k up until now) and loads of other trick stuff to make the high redline possible. It has plasma sprayed iron coated cylinder walls, CNC machined crankshaft, only 85mm crank height (115mm on the SF90, for example), triple vacuum remelted springs, etc. It also has more torque per liter which means they are able to get more work out of the combustion.

The Corvette engine is great and I am very happy that they decided to make it, but technically it doesn't seem to be any better than the Ferrari 458 engine and actually it's worse in some aspects. Maybe it's not completely fair to compare it to an engine from more than 10 years ago because of changing emission regs that make creating power more difficult, but it probably wouldn't be completely unfair to say that the Corvette engine is where Ferrari was 10 years ago. The Cosworth engine is where NA engines could have been if the development didn't stop and go towards turbos. Now let's just hope it's reliable .

Torque is not the simplest way to understand this. Most people simply don't understand it.

Acceleration = nett engine power / road speed

Done.

 

[TougeSpirit]

Just noticed that on Gordon Murray Automotive's site that they finally quote a downforce for the T50. They are stating 322 kg downforce (which I assume is at top speed, like the value for the T50.S). That's actually not bad at all for a car this clean.

That translates to about 153 kg downforce at 155 mph to compare to some other manufacturers. This is about comparable to what Ferrari claimed for the 458, although I trust GMA a bit more than Ferrari in this respect.

 

[Bridster]

Just noticed that on Gordon Murray Automotive's site that they finally quote a downforce for the T50. They are stating 322 kg downforce (which I assume is at top speed, like the value for the T50.S). That's actually not bad at all for a car this clean.

That translates to about 153 kg downforce at 155 mph to compare to some other manufacturers. This is about comparable to what Ferrari claimed for the 458, although I trust GMA a bit more than Ferrari in this respect.

Actually they had that info on there since the unveiling of the T.50S early last year . In any case, I think the downforce at 250km/h is gonna be even higher. 322kg is, as you say, at top speed, but very likely they start bleeding the downforce way before that - that's the whole point of the fan, after all! The 322kg could already be reached at 250km/h. We don't really have a definitive figure but from the comments GM made about the T.50S - which he said makes 3x the downforce of the T.50 - it could be deduced that the T.50 creates about 275kg of downforce at 250km/h (155mph). That's about the same as the 991.2 GT2RS (289kg). The 720S is 242kg and the 765LT is 302kg. Keep in mind, though, that claimed downforce figures are one of the more unreliable stats that manufacturers list. These numbers could be true, or they could also be completely, wildly different .