Direct Injection

[atr_hugo]

Here's a little light reading on Direct Fuel Injection. There are a whole bunch of benefits to injecting fuel in the combustion chamber as opposed to the intake tract; lean burn, injector timing independent of the valve operation, and enhanced overlap of the valvetrain being among them.

DFI is GOOD DOG FOOD!!

[Wiggum]

As an owner of a DI car, I can say it works well... though it may not be the best for heavy modifiers...

With the Mazdaspeed6 as an example, the high pressure fuel injectors seem to support anything you throw at them, but getting a pump to do it is another story...

One benefit you didn't list is the fuel actually cools the chambers before it combusts


EDIT: Just wanted to add, on a Mazdaspeed6, Direct Injection seems to add a lot of sound, my wife has the same car (non turbo, standard fuel injection) and I can hear the car fire on the Mazdaspeed. If you pop the hood and listen to it idle, you can literally hear every firing of the cylinders...

[atr_hugo]

Here's another link.

[imported_MPower]

Originally Posted by Wiggum

EDIT: Just wanted to add, on a Mazdaspeed6, Direct Injection seems to add a lot of sound, my wife has the same car (non turbo, standard fuel injection) and I can hear the car fire on the Mazdaspeed. If you pop the hood and listen to it idle, you can literally hear every firing of the cylinders...

I common observation people have regarding a direct injected vehicle is the clatter at idle, almost diesel-like sometimes.

[Wiggum]

Yeah, chatter would describe it well...

[atr_hugo]

Hmmm - what's the valvetrain actuation in the Mazda6? They aren't still using mechanical acutation are they (like the early NB Miatas)?

[imported_MPower]

I believe that the latest Mazda6s switched to electronic throttles. Could be wrong though.

[Wiggum]

Yes, electronic...

The 2.3L MZR DISI from Mazda is very different than anything else I have seen around...