[AWSAWS]

Yesterday I dynoed my car. 335i MSport, DCT. Mods below.

Temp was about 18C. I only ran the BMS JB4 MHD race flash. so I might be able to get better numbers with the E85 flash and more timing advance. Timing on all cylinders was good so it should be possible.

Power was a little under what I had hoped for. Came out at 459.8 at the crank, 386.2 WHP. The car feels nice though.

Best part was getting 530 ftlbs Torque at the flywheel. Stock is apparently 295 ftlbs and a stock 335D is 428ftlbs. This explains why I went through rear tyres in 6 months and why I just can't get grip for a good 60ft time at Santa Pod. The wheels spin like crazy. Even on the dyno the technician was struggling with wheel spin. I'm wondering if this may be why the chart dips and peaks on the Torque reading.

Runs were done in 4th, not 3rd like was printed on the sheet.

I have ordered some Vargas Inlets to see if I can get a bit more top end performance, where the Torque x rpm gives a good HP figure. Looks like the car runs out of puff by 5400 rpm.

Power at crank:


AFR:


WHP and Crank power:


Log timing:

[Cerbera9]

Excellent results you must be happy!!
Are these standard turbos or Vargas turbos?
Were you running ethanol?
I must admit the toque curve does look a little odd shaped (as you say wheelspin) and starts very high @ 2400 rpm
I'm surprised your IAT's were 43degrees with Meth, I had a similar figure on the dyno without meth.

[AWSAWS]

Originally Posted by Cerbera9

Excellent results you must be happy!!
Are these standard turbos or Vargas turbos?
Were you running ethanol?
I must admit the toque curve does look a little odd shaped (as you say wheelspin) and starts very high @ 2400 rpm
I'm surprised your IAT's were 43degrees with Meth, I had a similar figure on the dyno without meth.

Stock turbos mate, running 20% ethanol. The car was on the dyno and running for a long time. Calibration runs, checking car was aligned square. So iat temps were very good. It wanted to move on wot when not aligned right. If I add 15% to make this line up to dynojet numbers like I read about in the states then yes I'm happy. I always tell people the car feels like a diesel and the torque levels explain it!

[AirAndre335i]

Nice numbers! But... im surprised the WHP is so much lower than the BHP. Isn't it usually a 10% difference on a RWD?

[Aragorn30d]

Depends on lots of factors, including the dyno itself.

[windymissile]

Guys.
Bhp is Brake horse power. So, measured at the brakes. And the same as whp.

Hp is the general term and refers to the power the engine produces before losses. So Fly wheel hp.

General consensus on transmission losses is anything from 10-20 %. Autos lose a little more as do 4x4.
The numbers seem pretty solid for the mods and I'm a big believer in the theory that the area under the curve is more important than peak numbers. Especially in out cars that are designed to generate all their power in the low and mid range. This makes the car a lot faster than the numbers would suggest.

WM

[Aragorn30d]

The "brake" in BHP doesnt refer to the brakes on the car. It refers to using a braked dynamometer to measure the engines power.

Clearly we cant measure BHP, without removing the engine from the car and attaching it to an engine brake. So instead, chassis dynos measure wheel horsepower, and translate that into an approximation of BHP using various methods. Ofcourse its always an approximation, but on decent chassis dynos its an approximation that is pretty close to reality as the manufacturer spends a lot of time getting it right.

[windymissile]

Braking force required to overcome the power (torque) of the engine. Traditionally measured by the brakes. Now measured by a dyno meter.
The point of test remains the same. Calculated transmission losses remain but are well estimated.

WM

[Aragorn30d]

The brake was always external, and the term was derived long before automobiles came along:

https://en.wikipedia.org/wiki/De_Prony_brake

Invented in 1821.

[AWSAWS]

Originally Posted by windymissile

Guys.
Bhp is Brake horse power. So, measured at the brakes. And the same as whp.

Hp is the general term and refers to the power the engine produces before losses. So Fly wheel hp.

General consensus on transmission losses is anything from 10-20 %. Autos lose a little more as do 4x4.
The numbers seem pretty solid for the mods and I'm a big believer in the theory that the area under the curve is more important than peak numbers. Especially in out cars that are designed to generate all their power in the low and mid range. This makes the car a lot faster than the numbers would suggest.

WM

Agreed!

The power the 335i makes in the lower\middle rev range is right up towards the top end of high revving engines. So for a lot of the rev range the 335i is making more power for longer.

[Aragorn30d]

This is the whole advantage of a turbocharged engine and why they're so popular.

Wether its a little 1.0 Ecoboost fiesta or a 335i, the turbo makes the area under the curve much larger, and thus makes the car feel a lot more powerful when driving "normally". It works especially well on the smaller engines too, as they're so marginal on power for day to day driving, the turbo makes a massive difference.

It really puzzles me why it took BMW so long to realise this, ESPECIALLY on their smaller 4 cylinder engines. A 3 litre 6 goes alright without a turbo, whereas a 4 cylinder 2 litre petrol is just going to be gutless unless your revving the guts out of it, especially when compared with the equivalent TDI. VAG figured that out EONS ago, but BMW has only finally twigged in the last few years.

[AWSAWS]

Originally Posted by Aragorn30d

This is the whole advantage of a turbocharged engine and why they're so popular.

Wether its a little 1.0 Ecoboost fiesta or a 335i, the turbo makes the area under the curve much larger, and thus makes the car feel a lot more powerful when driving "normally". It works especially well on the smaller engines too, as they're so marginal on power for day to day driving, the turbo makes a massive difference.

It really puzzles me why it took BMW so long to realise this, ESPECIALLY on their smaller 4 cylinder engines. A 3 litre 6 goes alright without a turbo, whereas a 4 cylinder 2 litre petrol is just going to be gutless unless your revving the guts out of it, especially when compared with the equivalent TDI. VAG figured that out EONS ago, but BMW has only finally twigged in the last few years.

By the looks of it many manufacturers are just realising but I think they've more or less been forced into it by emissions regulations. The pluming that goes with an FI is fairly substantial and there's more complexity around engine management. BMW did a great job in creating what is just about a lagless turbocharged car, that doesn't feel like traditional FI cars of the past.

[djgandy]

Originally Posted by Aragorn30d

This is the whole advantage of a turbocharged engine and why they're so popular.

Wether its a little 1.0 Ecoboost fiesta or a 335i, the turbo makes the area under the curve much larger, and thus makes the car feel a lot more powerful when driving "normally". It works especially well on the smaller engines too, as they're so marginal on power for day to day driving, the turbo makes a massive difference.

It really puzzles me why it took BMW so long to realise this, ESPECIALLY on their smaller 4 cylinder engines. A 3 litre 6 goes alright without a turbo, whereas a 4 cylinder 2 litre petrol is just going to be gutless unless your revving the guts out of it, especially when compared with the equivalent TDI. VAG figured that out EONS ago, but BMW has only finally twigged in the last few years.

I don't think it is a case of realising. The problem with turbos is cost, reliability and weight. The only reason we are going turbo now is emissions. You can shrink the engine and internal friction but still get the same power.

VAG group has a lot more engineering power than BMW to churn out 1.4l engines. Even then the first round of TFSI engines was poor for power. BMW NA engines could out do them (RS models excepted)

[RajB]

Nice figures and impressive plots. Still haven't had mine done yet as we went to Surrey RR but I had issues with 30FF so didn't get a proper run.

[Cerbera9]

Originally Posted by RajB

Nice figures and impressive plots. Still haven't had mine done yet as we went to Surrey RR but I had issues with 30FF so didn't get a proper run.

Did you find out what was causing the 30FF code?

[Aragorn30d]

Originally Posted by djgandy

I don't think it is a case of realising. The problem with turbos is cost, reliability and weight. The only reason we are going turbo now is emissions. You can shrink the engine and internal friction but still get the same power.

VAG group has a lot more engineering power than BMW to churn out 1.4l engines. Even then the first round of TFSI engines was poor for power. BMW NA engines could out do them (RS models excepted)

Agreed, emissions are pushing the mass market, but the simple fact is that for a daily car, the turbo cars are quite simply nicer to drive.

Not really sure what you mean by BMW NA engines outdoing TFSI's... The TFSI was introduced in 2005 and the 2.0 version made 200hp in basic trim, reaching up to 270ish in the S3/TTS trim. A few detuned 170/180hp variants were made for lower class cars like the Seat Leon etc.

BMW's best 2.0 petrol made a maximum of 170hp, and the 170hp version of the N43 engine only came in around 2007? the previous N46 motor made quite a bit less power.

And a look at the torque figures tells the whole story, the N43 has 210nm at 4250rpm. The 2.0 TFSI has, in 200hp trim, 300nm between 1700 and 5000rpm.

Even the older 1.8T motor was convincingly better in tractability terms than the best 2.0 production engine BMW has ever built. Even the lowest spec 150hp version from 1995, has more torque available throughout the midrange compared to BMW's best efforts with the N43 engine. Which is exactly why VAG built the 1.8T in the first place. You end up with an engine that both drives better and uses less fuel.

As for complexity, the VAG 1.8T is a pretty simple engine when compared with all the valvetronic/vanos gubbins found on a modern BMW petrol engine, so the complexity and cost arguement doesnt really hold any water IMO.

[djgandy]

Originally Posted by Aragorn30d

Agreed, emissions are pushing the mass market, but the simple fact is that for a daily car, the turbo cars are quite simply nicer to drive.

Not really sure what you mean by BMW NA engines outdoing TFSI's... The TFSI was introduced in 2005 and the 2.0 version made 200hp in basic trim, reaching up to 270ish in the S3/TTS trim. A few detuned 170/180hp variants were made for lower class cars like the Seat Leon etc.

BMW's best 2.0 petrol made a maximum of 170hp, and the 170hp version of the N43 engine only came in around 2007? the previous N46 motor made quite a bit less power.

And a look at the torque figures tells the whole story, the N43 has 210nm at 4250rpm. The 2.0 TFSI has, in 200hp trim, 300nm between 1700 and 5000rpm.

Even the older 1.8T motor was convincingly better in tractability terms than the best 2.0 production engine BMW has ever built. Even the lowest spec 150hp version from 1995, has more torque available throughout the midrange compared to BMW's best efforts with the N43 engine. Which is exactly why VAG built the 1.8T in the first place. You end up with an engine that both drives better and uses less fuel.

As for complexity, the VAG 1.8T is a pretty simple engine when compared with all the valvetronic/vanos gubbins found on a modern BMW petrol engine, so the complexity and cost arguement doesnt really hold any water IMO.

Sorry, I was talking about the sub 2.0l engines, which are pretty gutless for turbo engines, although granted, better than BMW NA engines of similar size. Guess I just expect a little more from a turbo.

[windymissile]

Originally Posted by Aragorn30d

The brake was always external, and the term was derived long before automobiles came along:

https://en.wikipedia.org/wiki/De_Prony_brake

Invented in 1821.

But still. It's the braking force required to overcome the engine power.
I was explaining the simplest way of referencing power in regards to cars. Brake hp is measured at the brakes (or wheels if you like, no difference).
Hp is a way of referencing the power of the vehicle (engine, at the flywheel).

If reference is made to bhp then it's assumed this is at the brakes/wheels and is actual power to the road.
If reference is made to hp, this is pure engine turning force before gearing is applied.

As someone already said, every dyno is different and there is no standard, worldwide correction factor. And there are so many variables. Even something as simple as tread depth can change the numbers! So it's all a bit pointless for referencing against others.

It is however, great for dyno shootouts with your mates at a dyno day. Great for pub bragging rights. And before - after comparison of mods.
Also fault finding as you can have the vehicle at any rpm (but no load, another variable)

I wish you would have done runs with / without meth, Jack. So we could get a good feeling of the differences.

WM

[Aragorn30d]

Your still incorrect windymissile.

BHP refers to crank horsepower, measured at the engine output flange itself using a brake. It does not include transmission and drivetrain losses. The brake is an external device, used to measure the engines power on a test bed.

Its NOT a measure of power measured at the vehicles wheels or at the vehicles brakes.

Wheel Horsepower, is what you get at the tyres of the car, and takes into account energy lost in the transmission/driveline/tyres etc.

Your conflating two different things.


Definition here:

https://en.wikipedia.org/wiki/Horsep...ower_.28bhp.29

[windymissile]

Incorrect..? Where was the argument..?
We were saying the same thing.
I was not disagreeing with you. Maybe we just use 2 different terms for the same thing.
I do see what you are saying and always have. I was just explaining that the common referenced figures these days are different and explained differently. Maybe I didn't get my point across very well, and reading back, I did get a little side-tracked.
Not everyone has an understanding of what the 2 figures actually mean and struggle to separate the 2.
As far as I am aware, for as long as I have been driving, the bhp figure has always been the power to the wheels. Regardless of the origin of the measurement. It was just a term used to explain the power of the vehicle.
Maybe it's a geographical thing.. maybe it's just my understanding. I'm quite aware of what the technicalities of the term imply but the used terminology has never really matched up.
WM

[Aragorn30d]

Your saying BHP is power to the wheels.

Its not.

Its power available at the engines crankshaft.

That power then passes thru various transmission components (the gearbox itself, CV joints, shafts, diff etc) all of which use up a bit of that power thru friction and heat etc, and the power at the wheels is then less.

BHP = crankshaft power
WHP = Wheel power

So my 330d for instance left the factory with 233hp. Thus it has 233BHP. It probably has around 200hp at the wheels, or "WHP".