❓ QUESTION Does 2.0 has 400 HP ?

Matt

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I am curious about the actural horsepower of 2.0 EMIRA. LOTUS claimed that FE will have 400HP. Is it 400HP on wheels? Also, why some manufacturers overstate the horsepower? For instance, MY GT86 only has 135HP on wheels, but TOYOTA declared it would have 200HP when it was released. Another example is the opposite, TOYOTA claimed A90 SUPRA would have 340HP, and it acturally has 365HP on wheels ! I am so fonfused! o_O
 

Leonard

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I am curious about the actural horsepower of 2.0 EMIRA. LOTUS claimed that FE will have 400HP. Is it 400HP on wheels? Also, why some manufacturers overstate the horsepower? For instance, MY GT86 only has 135HP on wheels, but TOYOTA declared it would have 200HP when it was released. Another example is the opposite, TOYOTA claimed A90 SUPRA would have 340HP, and it acturally has 365HP on wheels ! I am so fonfused! o_O
Almost all manufacturers quote flywheel bhp not at the wheel.
Both the GT86 and Supra higher bhp figures are flywheel
 
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Matt

Matt

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Almost all manufacturers quote flywheel bhp not at the wheel.
Both the GT86 and Supra higher bhp figures are flywheel
But the strange thing is that SUPRA acturally has the claimed power on wheels. o_O
 

scoates

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No way the Supra has 386bhp another wheels
The one with the 6 port exhaust manifold might do, the one with the 2 port makes around 335bhp to the wheels and that is the quoted power figure in the literature. The 6 port Supra is quoted as 382 and makes roughly that to the wheels too as far as I know. Generally BMWs, to my understanding, are under rated for crank power and the quoted figures are closer to wheel horsepower for some reason.
 

Leonard

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The one with the 6 port exhaust manifold might do, the one with the 2 port makes around 335bhp to the wheels and that is the quoted power figure in the literature. The 6 port Supra is quoted as 382 and makes roughly that to the wheels too as far as I know. Generally BMWs, to my understanding, are under rated for crank power and the quoted figures are closer to wheel horsepower for some reason.
You must have a different model to us as we only list 335bhp as far as I am aware.
436bhp flywheel sounds a lot!
 

Eagle7

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This is has been an issue for decades; manufacturer's published power ratings. There's been a lot of fudging and misrepresentation over the years. To fix this, the Society of Automotive Engineers came up with their SAE standard that requires a manufacturer to have their engines certified by SAE to be within 3% of the published rating, and that's not 3% +/-, that's 1.5% +/-. So if an engine is SAE rated at 300 hp, the tolerance is 9 hp; it can be no more than 304.5 and no less than 295.5. This is the engine by itself, not in the car. If an engine is SAE rated, that's how close the tolerances are to the published figure. I don't know if the Lotus is going to be SAE rated, but hopefully it is.

Due to the many components and assemblies in a car's powertrain, there's a certain amount of power that's absorbed by all those factors before power makes to the wheels. That's called drivetrain loss, and that can range anywhere from about 12% to as much as 17%, although I've seen more in some cases. If you take 15% just for an example, on a 300 hp engine, that would mean 45 hp is being absorbed in drivetrain loss, so only 255 hp is making it to the wheels. The weight of all those components; flywheel, clutch, trans gears, driveshaft, differential gearing all absorb power to get them moving. Then add the resistance from the thick gear oils used in the trans and diff.

This can be improved by replacing factory components with better performance components, like a lightened billet steel flywheel, lighter twin disc clutch, more expensive gear oils in the trans and diff, and a carbon fiber driveshaft if the car has an aluminum shaft.

By reducing the drivetrain loss, that increases the amount of power to the wheels without having to do a thing to the engine. In the above example, if you can lower the loss from 15% to 12%, that allows 9 more hp to make it to the wheels. If you can get it down to 10%, that allows 15 more hp to the rear wheels, so now 270 hp is making it to the wheels instead of only 255. In addition, removing weight and resistance in the drivetrain enables everything to move quicker, so the car will accelerate quicker and be more responsive to throttle input.

The quickest, easiest and least expensive of those mods is replacing the gear oils, and you will notice the improvement right away. Flywheel and clutch (with labor unless you do it yourself) is going to cost maybe a grand or two depending on what you get. However if you do make those changes, the car will feel more lively, and less like it's pushing against a headwind when accelerating.

Supposedly the Emira has a lightened flywheel, but we don't know how much more lightened. Hopefully we can get that info. I'm planning on at least doing the gear oil upgrade. I'll look into the flywheel and clutch later, if I feel the car could benefit. It may be fine without it, but I won't know until I drive it.
 

scoates

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You must have a different model to us as we only list 335bhp as far as I am aware.
436bhp flywheel sounds a lot!

The EU market only gets the 2-port manifold which is the claimed 335bhp, the US and some other markets around the world from the 2021 model onwards gets the 6-port with a claimed 382bhp.

Here is a link to the Supra MKV forum which has some dyno graphs of stock cars. The first one shows a 2020 model Supra with 326bhp at the wheels, and a 2021 with 376bhp at the wheels.

You are right though that most manufacturers claim flywheel horsepower and not at the wheels, but for the examples at the top of the thread here the GT86 is definitely flywheel, and the Supra is closer to wheel horsepower. I think it is most likely the Emira's claimed 400bhp will be at the flywheel, more similar to the GT86 than the Supra in terms of quoted vs real figures.
 

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You must have a different model to us as we only list 335bhp as far as I am aware.
436bhp flywheel sounds a lot!

The 2020/2021 model of the Supra had the slightly less powerful B58, right after that they updated it with the exact same B58 with the updated manifold as the Z4 m40i with and it makes closer to 380hp.

They are indeed underrated -- typical BMW things. Some mfg have a history of quoting power in the worst case scenarios which usually matches dynos at whp. My M4 put down roughly claimed HP to the wheel on a dynapack. Lots of variables here in dynamometer testing obviously though.
 

Leonard

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The 2020/2021 model of the Supra had the slightly less powerful B58, right after that they updated it with the exact same B58 with the updated manifold as the Z4 m40i with and it makes closer to 380hp.

They are indeed underrated -- typical BMW things. Some mfg have a history of quoting power in the worst case scenarios which usually matches dynos at whp. My M4 put down roughly claimed HP to the wheel on a dynapack. Lots of variables here in dynamometer testing obviously though.
Suprises me that BMW read so high. Recently only had a 335i and an M2 Comp but both seemed on the money manufacturer quoted bhp wise
 

kitkat

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Suprises me that BMW read so high. Recently only had a 335i and an M2 Comp but both seemed on the money manufacturer quoted bhp wise
The s55 m2 comp puts down considerably higher bhp — those are a absolutely putting down (average across types of dynos) 400whp. The Emira will likely be putting down 60whp less than your M2.
 

Leonard

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The s55 m2 comp puts down considerably higher bhp — those are a absolutely putting down (average across types of dynos) 400whp. The Emira will likely be putting down 60whp less than your M2.
Not trying to start an argument 😁 but there is no way my M2 was putting down anymore power than 410bhp at the fly. It wasn't really that fast if I'm honest. Acceptable but not silly fast. Terrifying in the wet and cold on Cup 2s though 😅
 
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400HP??
I believe both the official web and the third party webs claimed the power output for the Emira I4FE is 360HP(365PS)/ 420NM.

I believe all officially claimed are power at the crank, not
at the wheels.

Yeah, some manufactures likes to understate the output, like BMW (that’s why sometimes their power at wheel tested on the dyno is even higher than officially claimed power at crank. ) But mostly don’t, such as Porsche/Ferrari.
 

Nova

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400HP??
I believe both the official web and the third party webs claimed the power output for the Emira I4FE is 360HP(365PS)/ 420NM.

I believe all officially claimed are power at the crank, not
at the wheels.

Yeah, some manufactures likes to understate the output, like BMW (that’s why sometimes their power at wheel tested on the dyno is even higher than officially claimed power at crank. ) But mostly don’t, such as Porsche/Ferrari.
The Chinese lotus website has listed 400 HP for the I4. Might be region specific, but it does leave one to wonder.
 

lion shf

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I’ll be doing this. Not the least bit worried about 360hp
 

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