Hmmm spend a ton of $$$ now, or wait for next-gen Z with direct injection?

[370Zsteve]

You know it's coming.

[theDreamer]

Probably not for another four years at least, so I am having fun with this car. DI is nice but not sure it is going to be some that turns the Z into a 450hp/350torque car.

[kannibul]

Originally Posted by 370Zsteve

You know it's coming.

Direct Injection doesn't (really) make HP. It makes MPG...

[370Zsteve]

Originally Posted by theDreamer

Probably not for another four years at least, so I am having fun with this car. DI is nice but not sure it is going to be some that turns the Z into a 450hp/350torque car.

DI is the wave, baby. Catch the wave. Don't be surprised if they drop DI into the existing Z, could be less than 4 years if that's the case.

BMW's TT DI inline-six produces 330 lb ft of torque (in the 7 Series), not so far away from your number...throw in the added power, the fuel economy boost, the better emissions and you have incentive for Nissan, especially as the Euros seem hell-bent on stricter and stricter emissions standards.

[370Zsteve]

Originally Posted by kannibul

Direct Injection doesn't (really) make HP. It makes MPG...

You crazy.

[kannibul]

Originally Posted by 370Zsteve

DI is the wave, baby. Catch the wave. Don't be surprised if they drop DI into the existing Z, could be less than 4 years if that's the case.

BMW's TT DI inline-six produces 330 lb ft of torque (in the 7 Series), not so far away from your number...throw in the added power, the fuel economy boost, the better emissions and you have incentive for Nissan, especially as the Euros seem hell-bent on stricter and stricter emissions standards.

Two key letters in that BMW...

TT

Once you start talking forced induction...

[kannibul]

Originally Posted by 370Zsteve

You crazy.

Show me evidence that the only change is direct injection, and HP/Tq is gained.

[370Zsteve]

Originally Posted by kannibul

Show me evidence that the only change is direct injection, and HP/Tq is gained.

Of course DI involves other changes. When you further digitize the fuel delivery process, things like VVEL become even more efficient.

Wiki:

The major advantages of a GDI engine are increased fuel efficiency and high power output. In addition, the cooling effect of the injected fuel and the more evenly dispersed mixtures allow for more aggressive ignition timing curves. Emissions levels can also be more accurately controlled with the GDI system. The cited gains are achieved by the precise control over the amount of fuel and injection timings which are varied according to the load conditions. In addition, there are no throttling losses in some GDI engines, when compared to a conventional fuel injected or carbureted engine, which greatly improves efficiency, and reduces 'pumping losses' in engines without a throttle plate. Engine speed is controlled by the engine control unit/engine management system (EMS), which regulates fuel injection function and ignition timing, instead of having a throttle plate which restricts the incoming air supply. Adding this function to the EMS requires considerable enhancement of its processing and memory, as direct injection plus the engine speed management must have very precise algorithms for good performance and driveability.
The engine management system continually chooses among three combustion modes: ultra lean burn, stoichiometric, and full power output. Each mode is characterized by the air-fuel ratio. The stoichiometric air-fuel ratio for petrol (gasoline) is 14.7:1 by weight, but ultra lean mode can involve ratios as high as 65:1 (or even higher in some engines, for very limited periods). These mixtures are much leaner than in a conventional engine and reduce fuel consumption considerably.

• Ultra lean burn mode is used for light-load running conditions, at constant or reducing road speeds, where no acceleration is required. The fuel is not injected at the intake stroke but rather at the latter stages of the compression stroke, so that the small amount of air-fuel mixture is optimally placed near the spark plug. This stratified charge is surrounded mostly by air which keeps the fuel and the flame away from the cylinder walls for lowest emissions and heat losses. The combustion takes place in a toroidal (donut-shaped) cavity on the piston's surface.^{[citation needed]} This technique enables the use of ultra-lean mixtures impossible with carburetors or conventional fuel injection.
• Stoichiometric mode is used for moderate load conditions. Fuel is injected during the intake stroke, creating a homogenous fuel-air mixture in the cylinder. From the stoichiometric ratio, an optimum burn results in a clean exhaust emission, further cleaned by the catalytic converter.
• Full power mode is used for rapid acceleration and heavy loads (as when climbing a hill). The air-fuel mixture is homogenous and the ratio is slightly richer than stoichiometric, which helps prevent knock (pinging). The fuel is injected during the intake stroke.

Direct injection may also be accompanied by other engine technologies such as variable valve timing (VVT) and tuned/multi path or variable length intake manifolding (VLIM, or VIM). Water injection or (more commonly) exhaust gas recirculation (EGR) may help reduce the high nitrogen oxides (NOx) emissions which can result from burning ultra lean mixtures.

[370Zsteve]

Originally Posted by kannibul

Two key letters in that BMW...

TT

Once you start talking forced induction...

Oh, don't get me wrong...my OP is all about modding a DI engine as opposed to spending the money now. I have a lot of time on my hands, obviously.

[Nick911sc]

Haven't there been quite a number of cases of carbon build-up in engines running direct injection?

[spearfish25]

By the time the Z has direct injection, I'll be ready for a new one. Until then, I get to enjoy driving my sweet car rather than wait for something that may or may not be coming.

[Zsteve]

I know on my Audi TT with DI there was some concern with heavy deposits and cam follower damage. Im not sure if the Z was to get DI that that means it would have the same prob with the cam but the deposits will probably be there. But there has been no evidence that it is harming the car. I guess you would just need to run some type of cleaner every so often.

[Modshack]

Originally Posted by Nick911sc

Haven't there been quite a number of cases of carbon build-up in engines running direct injection?

Yes there have. Some of the pictures I've seen have not been pretty.... With direct injection the valves no longer get a flow of Gas which serves to keep them clean. The only air you get is mixed with Blow-by and contaminants (oil) from the PCV system which builds up on the valves and stems. I think Toyota employs an additional upstream injector to deal with this, but most don't. Pics of the VW 2.0 FSI and the Porsche Cayenne have been ugly.. Careful what you wish for.

Here's a pic of the newer VW/Audi 2.0 with direct injection (mileage unknown):


Here's a shot of a friend of mine's VW/Audi 1.8T (the engine that preceded the 2.0) with conventional injection, use of good gas, at 125,000 miles..

[SoCal 370Z]

Four years is long time to wait, if that's when the next Z is to be released. So many things can and will happen. If it is true that peak oil is at 2012, then who knows which direction vehicles will be heading and whether Nissan even sees fit that they continue the Z in its petrol driven guise. Interesting times are upon us to be sure...

[Zsteve]

Originally Posted by SoCal 370Z

Four years is long time to wait, if that's when the next Z is to be released. So many things can and will happen. If it is true that peak oil is at 2012, then who knows which direction vehicles will be heading and whether Nissan even sees fit that they continue the Z in its petrol driven guise. Interesting times are upon us to be sure...

I think we will see more 4 banger turbos now to help on MPG and still keep the power.