I read with much interest of the new engines that whilst providing more power, is more economical.

Well, firstly, Mitsubishi tried this several years ago with GDI )Gasoline Direct Injection. I presume, just going by the name, that the technology is similar. One of the main flaws of the engine was the requirement of using RON98 petrol and better... They ran it for a while before deciding that it wasn't going to work. I have not looked into the technicalities of both technologies but reckon that the principles are the same, pumping fuel directly into the combustion chamber.

Comments?

Also, does anyone know how BMW (or other car manufacturers for that matter) measure economy? Running the car at a certain temperature for a certain distance at a certain speed?

Comments?

Thank you.

 

This might help - take a look at this Edmunds article which discusses BMW's DI implementation - it's pretty interesting.

http://www.edmunds.com/insideline/do/Featu...rticleId=115127

 

Thanks swajames.... good article!

 

One of the main advantages is that the injection system now has the processing power and operating pressure to inject up to three times in one power stroke, this significantly improves the power and torque whilst reducing combustion chamber tempretures which makes it possible to run a 10.5:1 compression ratio with 0.8bar boost pressure on normal pump fuel.

 

Does anyway have an experience of the sound of DI engines...
I read somewhere that they can sometimes have a touch of almost diesel sounding 'clatter' especially at idle?

Is there any truth in that?

 

The injectors can be noisy but you have to bear in mind they operate at upto 200bar (1800psi).

 

Reading in the Lexus board indicates that is a problem. My d-i-l just got a RX350 and she hasn't noticed the noise. I just asked her to listen carefully when she starts from cold. I am about to order a Lexus GS350 and it uses the same engine with direct injection. If it's normal, I have no problems with it. So far no one in the Lexus board has been able to come up with a definite answer.

 

Yes, I heard on other forums that most of the ticking noise can be attributed to the direct injectors.
A lot of 335i owners are talking about how noisy direct injection is... same with those with the VW/Audi FSI engines...
Maybe Lexus/Toyota are better as they have been doing direct injection and 'lean burn' for years.

As BMW are late to the DI party, we only have the 335i to compare to. Would be interested to hear from those who have experience with this engine and also those who have a DI engine from another manufacturer.

 

just a thought. with diesels [dodge truck...] you need to change the fuel filter on a regular bases. the dirty fuel destroys the high pressure pump used in the DFI system. us gas owners have been rather lax about this and maybe we need to change????