Torque graphs of the new Valvetronic Inline-6 engines

Courtesy of BMW AG

325i left - 330i right

Does BMW try to make it's torque output equal its engine displacement? Or is that just an odd coincidence?

Originally Posted by STEVE46

Does BMW try to make it's torque output equal its engine displacement? Or is that just an odd coincidence?

Most efficient street car engines nowadays generate around 100 N-m of torque per liter.

Originally Posted by Jspeed

Most efficient street car engines nowadays generate around 100 N-m of torque per liter.

BMW's 2.0 litre inline petrol four: 200 Nm

Yup . But this only applies to petrol engines. BMW's diesels kick out anywhere from 170-190 Nm per litre.

Nice to see that dip eliminated!

Originally Posted by ff

You Europeans with your newton meters and killowatts and such...

I love the Metric System!


.

Originally Posted by ff

You Europeans with your newton meters and killowatts and such...

Originally Posted by STEVE46

Does BMW try to make it's torque output equal its engine displacement? Or is that just an odd coincidence?

Well.. It can't be an odd coincidence... I thought both engines were 3.0 litres?

Originally Posted by kyfdx

I thought both engines were 3.0 litres?

Not the European spec cars. It looks like the US spec cars will be getting the same engine (with different output) according to the order guides that's been mentioned here.

Originally Posted by andy_thomas

BMW's 2.0 litre inline petrol four: 200 Nm

Yup . But this only applies to petrol engines. BMW's diesels kick out anywhere from 170-190 Nm per litre.

The diesels are all turbo charged. If they were normally aspirated their torque would be lower than the petrol engines.

Originally Posted by Alex Baumann

Not the European spec cars. It looks like the US spec cars will be getting the same engine (with different output) according to the order guides that's been mentioned here.

Maybe a dumb question but if the displacement is the same, what do they change on the engine itself to get a different output out of both? Very confused.

Wouldn't that make it easy to mod a lower output car up to the higher output ones? People always say there's no substitute for displacement...

~Jon

That is quite impressive. 80% of peak torque available at 1100 rpm? Wow.

It is very common to use different cams for different applications. These affect the breathing of the engine and determine the torque characteristics. Usually, a light car would get more top end power at the expense of low end torque, and a heavier vehicle (SUV/RV/Truck) would get more torque at low speed at the expense of top end power.

BMW had an eta line of engines in the '80s that were optimized for torque and fuel efficiency. The 528e for example, had its power peak at about 4000 RPM and had no high RPM punch at all.

With double vanos (variable valve timing) and variable inlet track length or resonance there is much less need to make this compromise, and torque can be optimized through a much wider engine speed range. The valvetronic engines have so much torque at low speed that they would work well for SUVs and good top end power too.

It would be possible to limit power and torque by means of the engine controller software, but that would be silly. Even sillier than limiting the performance of a particular model by using very long gearing (low revving).

I seriously doubt that the US will get two derivatives of the 3 liter engine, with one called a "325" in that car. The graphs above strongly suggest displacement of about 2.5 and 3 liters. That does not mean there won't be two 3 liter engines with slightly different characteristics; like with the ZHP engine we have now.

Before variable valve timing it was common for hot rodders to replace the stock cams in their engines for ones that improved top end breathing. Today you have the best of both worlds, but it can still be done. The ZHP is BMW's version of such an engine.

Originally Posted by JAWJr

Maybe a dumb question but if the displacement is the same, what do they change on the engine itself to get a different output out of both? Very confused.

Wouldn't that make it easy to mod a lower output car up to the higher output ones? People always say there's no substitute for displacement...


~Jon

Originally Posted by dynosor

I seriously doubt that the US will get two derivatives of the 3 liter engine, with one called a "325" in that car.

It's in the ordering guide. Two three liter motors, one producing 185 lbs/ft peak torque and the other 220.

Maybe somebody can explain to me the advantages of a 325i motor that has been so drastically detuned from the 330i. It still runs on premium, according to the guide, so it won't save money at the pump.

Originally Posted by numbersguy

It's in the ordering guide. Two three liter motors, one producing 185 lbs/ft peak torque and the other 220.

Maybe somebody can explain to me the advantages of a 325i motor that has been so drastically detuned from the 330i. It still runs on premium, according to the guide, so it won't save money at the pump.

If this is really going to be the case, it's probably because displacement sells in this country. The general carbuying public in America will buy a 160hp 4.0l V6 over a 160hp 2.0l 4cyl, even if every other characteristic between the two were exactly the same.

Originally Posted by numbersguy

It's in the ordering guide. Two three liter motors, one producing 185 lbs/ft peak torque and the other 220.

Maybe somebody can explain to me the advantages of a 325i motor that has been so drastically detuned from the 330i. It still runs on premium, according to the guide, so it won't save money at the pump.

Australian brosure shows 2, 2.5 and 3 liter engines.

http://carpoint.ninemsn.com.au/Tig/U...ias=carpointau


I believe two three liter engines is a typo, but if this is correct, the only reason to do it is economy of scale:

You cover two marketing price points with only one investment in hardware. Same block, crank , head, etc. That suggests the differences are in cams, because if it is only in software, hacks will be selling cheap upgrades in a hurry.

Originally Posted by dynosor

You cover two marketing price points with only one investment in hardware. Same block, crank , head, etc. That suggests the differences are in cams, because if it is only in software, hacks will be selling cheap upgrades in a hurry.

But other markets worldwide will get the other displacements.

Originally Posted by Kaz

But other markets worldwide will get the other displacements.

That means the money has already been invested for other engines, so why not use them. The US drops the 2 liter engine; that is enough deviation.

Originally Posted by dynosor

That means the money has already been invested for other engines, so why not use them. The US drops the 2 liter engine; that is enough deviation.

Er, you just contradicted yourself. First you say it's economies of scale so they can use the same block/heads/etc. Then next you say they've already made the investment in the different parts. So which is it?

Based on this info from BMW on the 5 series, who knows...

http://www.bmwusa.com/bmwexperience/...tm?article=152

http://66.102.7.104/search?q=cache:_...+215+hp+&hl=en

"In order to offer improved performance while at the same time improving fuel efficiency and meeting ever more challenging emissions requirements, two 3.0-liter engines will be offered. In the U.S., the 525i and 525xi will offer a 3.0-liter engine which produces 215 hp (SAE net) and 185 lb-ft of torque at 2,750 rpm. Responsiveness in everyday driving situations is outstanding. Nearly 85 percent of peak torque is available from 1000 rpm all the way to 7000. The 530i and 530xi models will feature a 3.0-liter engine which produces 255 hp (SAE net) and 220 lb-ft of torque. Peak torque is available between 2750 and 4000 rpm. Here fully 90 percent of peak torque is available between 1500 and 6700 rpm."

Originally Posted by Kaz

Er, you just contradicted yourself. First you say it's economies of scale so they can use the same block/heads/etc. Then next you say they've already made the investment in the different parts. So which is it?

Ok, let me make my position clear. I don't know if BMW will offer two versions of the 3 liter engine, but I am trying to find evidence one way or the other.

I think that detuning the 3 liter engine could make sense if it allowed you to build more of the same engine, and not a 2.5 liter engine. As the rest of the world will be getting a range of engines, including a 2.5, offering two 3 liter engines is not being done for economy of scale.

Perhaps I should delete my previous posts or edit them as my opinion develops and new facts come into play. On the other hand, I think I have already edited some and thereby seem to be contradicting myself.

I was offering a potential reason for doing something, not stating that as fact. It seems the facts point away from economy of scale, in this instance.

Detuning might make sense if the detuned motor would run on regular. Which BMW owners would rejoice over a savings of $.25 per gallon? Many of the same ones who drive 325s and 525s with slushboxes. Yet the ordering guide says premium for both motors. Maybe THAT is the typo.

or they could just be putting it in there for bragging rights... look even our base model has a 3.0 liter engine...

It is not surprising to me at all that the US would get a 3 liter in both cars. The reason is that competition from other brands is so tough here .

I still don't get it..

I see that Europe is getting a 2.5 litre engine.. But, they are saying that the U.S. 325i will have a 3.0 litre engine..

And, yet.. coincidentally... The power specs for the 2.5 litre and the "de-tuned" 3.0 in the U.S. model are identical?

This just doesn't seem right.. I can't believe they will be building these cars in the next few weeks.. and, no one seems to know for sure..