Filed under: Euro, BMW, Rumormill
Rumormill: BMW working on twin-turbo four-cylinder?
Here's a juicy one. BMW Blog reports that it has two unnamed, independent sources who have spoken of a high-revving (how does 11,000 rpm sit with you?) new four-cylinder being developed for use in the 1-series. The power target of this fantasy mill is said to be 220 to 260 horsepower, and it would theoretically be offered in both naturally aspirated and twin-turbocharged forms.
If this rumor actually comes to pass (something that is far from guaranteed, to say the least), we're told to expect a 2010 release. Take it all with a very healthy dose of salt. That said, squeezing more power out of less engine is going to be a continuing trend as governments tighten the screws regarding fuel economy and emissions targets, so efforts from BMW in this realm wouldn't be the least bit surprising. We hope this rumor comes true, if only to be able to point to a shiny new 1-series coupe and say, "Ours goes to eleven... thousand."
[Source: BMW Blog]
Reader Comments (Page 1 of 3)
mcheddadi 11:34AM (4/09/2008)
HACHI ROKU!
Reply
Will 12:46PM (4/09/2008)
About 1200lbs too heavy. Sorry.
SOhp101 11:35AM (4/09/2008)
11k rpm? That's just some bimmer boy's wet dream.
Especially if it has a turbo (or twin turbo) attached to it, there's no way it would go that high.
Reply
Andrew 12:24PM (4/09/2008)
Crank speed and turbine speed is not a parallel relationship. Moreover, you have no idea what you're talking about, so let the real engineers decide what redline will be.
tuna 12:33PM (4/09/2008)
Not quite. More like some Hondaboy's wet dream. BMW drivers want usable power, that's a nice fat torque band, not some peaky engine with no low-end power. Otherwise, they would've bought a Honda.
MachinaDC5 12:45PM (4/09/2008)
I'm going to have to agree with tuna here. Many BMW drivers love how their cars reach peak torque output at 1200 rpm instead of 7000.
Franz 12:47PM (4/09/2008)
11k rpm with a turbo is nothing. Remember that F1 cars used to be turbocharged. Back in '83 the Brabham-BMW BT52 used to squeeze out over 1400hp out of that 1.5 liter 4 banger. Fast forward to present day and it should be a breeze for them to get 260.
Sean Flanagan 1:21PM (4/09/2008)
"BMW drivers want usable power, that's a nice fat torque band, not some peaky engine with no low-end power. Otherwise, they would've bought a Honda."
You should tell BMW that their customers don't want peaky engines, since the V8 in the E92 M3 makes peak torque at 3900rpm and peak power at 8300rpm, the I6 in the E46 M3 made peak torque at 4900rpm and peak horsepower at 7900rpm, and the V10 in the M5/M6 makes peak torque at 6100rpm and peak power at 7750rpm.
Duncan 1:21PM (4/09/2008)
Before Honda was making high-revving 4-cylinder mills BMW was king of displacement/liter in their M motors.
A light-weight high-revving small-displacement 1/3 series would be a return to what made BMW great.
260hp out of a N/A mill revving to 11k is about, what? 1.6 liters? 1.8 liters?
11k isn't "too high" for a turbo either. I believe there were some Nismo tuned R34 GTRs revving to 10k with turbos.
tenfifteen 1:49PM (4/09/2008)
@ Sean Flanagan
The quote was "a nice fat torque band," which all of the engines you mention possess, irrespective of where their *peak* torque lies. All of those engines have roughly 85% of their peak from 1500rpms to within 1k of redline. Very flat, very FAT torque bands.
why not the LS2LS7? 6:43PM (4/09/2008)
An impeller won't work great at a mere 11K rpm. The turbos in my car work go up to 50K rpm stock, and people have chipped them to a lot more.
SOhp101 6:44PM (4/09/2008)
Except nearly everyone that's replying is forgetting that one huge difference between an F1 engine and the ones in the cars they sell is that the former only has to last one race whereas the other is supposed to last for years. A little difficult to make a turbocharged engine that revs that high AND will last longer than just a few thousand miles.
Franz 7:42PM (4/09/2008)
I don't think anyone has forgotten that. It's just that when put it into perspective, an F1 motor that runs and full throttle for probably 90% of the time during a 70 lap race while putting out well over 1000hp should be pretty reliable detuned to about 260hp. Remember, the 4 pot F1 engines I'm referring to were built way back in the 80s, and were based on production blocks with over 100,000km on them to begin with. Current f1 mills spin reliably to 18k rpms and have to last 2 race weekends @ full throttle. That's practice from Thursday through Saturday, plus qualifying and the actual race... twice. Plus turbo tech has come a long way since the 80s, with ball bearing, water and oil cooled center sections, variable vane technology and stronger lightweight materials. I just don't think it's as big an engineering challenge as you'd think.
Franz 7:51PM (4/09/2008)
Also, there isn't a direct relationship between engine speed and turbine speed, since a turbo runs off exhaust gases. It all has to do with how much exhaust flow the hot side is allowed by the wastegate.
mk 11:40AM (4/09/2008)
More power requires more fuel, it isn't just air.
And why twin turbos on a four cylinder engine? I know others have done it, even subaru had twin sequential turbos on a flat four.
It is overly complex, and heavier. Why not just a good twin-scroll 4-2-turbo-1 exhaust system, or even a variable-vane turbo.
Much less equipment, plumbing, and fewer transitions than twin turbos.
A nice BMW turbo I4 would be great. Twin turbos just seem superfluous on a 4-cylinder, 4-stroke engine.
Reply
hashiryu 1:31PM (4/09/2008)
agreed 110%
jim 4:58PM (4/09/2008)
Why twin turbos? To eliminate turbo lag, one provides maximum boost at low RPMs and the other handles high RPM boost.
smithsp 11:45AM (4/09/2008)
Read the link a little further, it states the same sources claim they are developing a quad-turbo I4.
This is BS, for sure.
Reply
cowboy bob 11:48AM (4/09/2008)
Turboschmerble. Give me simplicity and reliability. This combo is usually the money saver. Everything is wonderful 'till the thing is seven/ten years old. Then the moneypit harkens.
Reply
fm 2:38PM (4/09/2008)
An engine not being turboed doesn't suggest simplicity. Conversely a turboed engine doesn't have to be short lived and expensive. Curent F1 engines are not turboed yet are FAR from being simple.
Engine wear is dependent on the build and the driver. Thrash the car around day in day out and even the best most simple engine like a big block v8 won't last long. Even hightech engines designed to take the wear and tear of F1 racing only last about 2 races. But put that engin in a commuter's car and who knows how long that thing can last? Of course having that pit crew warming you engine a few hours before you leave every day would be a bit impractical not to mention expensive.
I understand your point. Simple=cheap. My point is "simple" is a term used to describe 100 years of engineering. Nothing is "simple" apart from 1+1=2. Then again how long do you figure it took cavemen to figure that out?