Direct injection idea

[72240z]

Anyone ever think of fitting a set up on a napz motor? Seems like it would be pretty strait forward to do. Run a standard I4 dizzy and use the 2nd bank of spark plug holes to mount proper injectors.

 

Just for the sake of convo.......

[datzenmike]

Yes I have! The reg distributor will work with four wires missing or the four plug distributor from an early S11 200sx. Better would be the CAS from a later Z24i distributor for the EFI. For a direct injector could one from a diesel be modified to work???

[72240z]

You know I didn't even think of just taking 4 wires off the stock dizzy lol der. I though about a diesel set up 1st but don't diesel injectors run some ridiculous pressure like 30k psi?

 

Could use stock direct injectors, nissan for example has a model of the vk45 that is DI, the vk45dd. 4.5v8/2=2.25I4, pretty close to a 2.4 so they should be suitable displacement wise. Thats just an example though I bet they cost an arm and a leg each, surely there is a cheaper option.

 

I just read GM has a 2.4 DI engine coming too.

 

Fitment could be cheap/easy, weld the matching injector bung to the bottom half of a hollow injector or just thread a bung with a longer neck.

[thisismatt]

Wouldn't you have issues with fuel atomization / air/fuel mixture?

[72240z]

Thats definitely possible. I don't think so though esp in the napz, because the way the valves are positioned there is naturally good swirl.

 

Edit: I mean it would allow you to run higher then average comp ratio as well, that would help too no?

 

EFI in general I would think to be intensive as far as control too.

Edited January 5, 2009 by 72240z

[jesusno2]

I don't think it would work what the hell would be the point of the valves?? I don't think you could ever get the mixture right. I guess if ya didn't have anything better to do than go for it. Napz motors are kinda a waste of aluminum anyways well the head is. Please carry on.

[72240z]

I don't think it would work what the hell would be the point of the valves?? I don't think you could ever get the mixture right. I guess if ya didn't have anything better to do than go for it. Napz motors are kinda a waste of aluminum anyways well the head is. Please carry on.

 

Well that is one way of looking at it.

 

Another would be that the valves would still have the same job? The point being superior power(esp at low rpm) AND better mpg. Many manufacturers have been getting the mixture right for some time including nissan as pre-mentioned. Given what I thought were obvious benefits, I think its more then "if you have nothing better to do".

 

You can think that about the z24 if you like, I just don't agree at all. It has its down points, like every other motor in existence. Trying to improve them kind of makes sense no? or is that just me? lol

Edited January 5, 2009 by 72240z

[ggzilla]

I doubt you could do direct injection. That takes a new cylinder head, maybe even a new chamber design. Only a few of the very latest gasoline engines are using Direct Injection.

 

Are you talking about mechanical fuel injection?

[510er]

I think it would work, hell they have been doing it in Two strokes for years!

[72240z]

Why would it take a new head?

[datzenmike]

I should imagine the EFI would adjust the mixture ratio with feedback from the O2 sensor. For that, get a Z24i manifold it has the O2 sensor. Although you would probably want one of the newer wide band ones:

 

Z24 and Z24i exhaust manifolds.

http://i138.photobucket.com/albums/q251/datzenmike/720%20stuff/exhaustmanz24andz24iLarge.jpg[/img]"]

 

I think an EFI from a KA or SR system might be grafted over but usually direct operates at higher fuel pressure and the injection timing is varied. Direct injection gains it's advantage in economy by being able to vary the injection timing... ours won't. I think it could be made to work but not all of the advantages can be realized.

[72240z]

Ya for EFI I thought about the same. If you run sr or ka EFI you can use nistune or equivalent to change the maps/timing and even run a wide band and map sensor. A/F would not be a problem at all. All that control comes cheap too, $100 for a wideband, $250 for the nistune and like $50 for a ka harness and ecu/sensors. $400 for fully controllable ecu that retains stock amenities? I'll take that any day of the week.

[ggzilla]

Direct Injection is very rare in a gasoline engine. It takes a diesel style pump, but more important extreme calibration (e.g. computer, or very expensive gear) and special head desing. The gasonline is injected into the cylinder, not into the manifold or into the ports.

 

The 1955 Mercedes-Benz 300SL, the first sports car to use fuel injection, used direct injection.

Perhaps the most expensive car of 1955.

 

It was not until 1996 that gasoline direct injection reappeared in the automotive market. Modern computer & knock sensor electronics make it less expensive to control now.

...

Toyota introduced its direct-injection engine .... in the 2000 Toyota Avensis.

...

General Motors ... three such engines have been introduced: in 2004, a 155 hp (116 kW) version of the 2.2 L Ecotec used in the Opel Vectra and Signum

 

Read up about it: Gasoline Direct Injection

Perhaps some of you guys are thinking about Port injection or multi-port injection.

Edited January 5, 2009 by ggzilla

[72240z]

Direct Injection is very rare in a gasoline engine. It takes a diesel style pump, but more important extreme calibration (e.g. computer, or very expensive gear) and special head desing. The gasonline is injected into the cylinder, not into the manifold or into the ports.

 

Perhaps the most expensive car of 1955.

 

 

 

Read up about it: Gasoline Direct Injection

Perhaps some of you guys are thinking about Port injection or multi-port injection.

 

I don't care how rare it is personally, took quite a long time for fuel injection to catch main stream, don't care about how much a 55 benz costs either. I also can only speak for myself but I am well aware of what direct injection is. Idk what you mean by diesel style pump. 2k psi fuel pump with a/n fittings doesn't seem that bad to me.

 

If it was invented requiring no computer control by retrofitting a standard head, pardon me for saying I bet good money It could work for with a napz head. The z24 head is already tapped across from a plug and has a well documented swirl effect, the injectors atomize the fuel to the micron. Idk what special head design you mean as everyone I have seen besides the injector follows suite with conventional heads. More over the 1st one was on a retrofitted conventional head 20years older then the napz so....

 

It CAN be done. There is no black magic involved here. Same computer controls apply as do the sensors. How much of a benefit can be had is a different question.

[ggzilla]

Look forward to seeing your results. I've never heard of a retrofit, can you share more information on that?

[72240z]

Oh I'll most likely never be doing it. Like the 1st post says its just for convos sake. There was no animosity intended in my response, rebutting is all.

 

If I had a z24 I would try it in a second but I don't. I know though a lot of people here use this motor and thought talking it out might give them some ideas or help start the ball rolling. When I look at the motor the idea just makes sense to me so I posted it.

 

Hairbrain schemes I actually plan to do and post will be coming soon, I6 itbs with variable length trumpets, mad max style sc for the vg. Maybe if I can find a fuel maker cng injection, super high comp L30 etc....

[datzenmike]

To gain a mileage advantage, direct injection can run air fuel ratios an lean as 60 to 1. At very light loads and light throttle the injector puffs a minute cloud of fuel directly around the plug and mixes only with the air in the vicinity requiring that the injector pulse be at or very near the spark timing lest the fuel dilute with the rest of the air in the cylinder. Under heavy load regular air/fuel ratios are used and the injector pulse is much much earlier to allow thorough fuel air mixing in the cylinder. To do this there are sensors and complex computer algorithms to control the injector timing etc. etc.

 

I know it could work, but without this precise control it would only be better than port injection. Economy wise it would fail, but for performance it might still be good, maybe even great. Fun to wonder... what it we....?

[72240z]

Ya thats the thing, getting it to work doesn't seem worth arguing to me, its totally doable, the gains are the question.

 

I think econ would still benefit because you could jump comp pretty high which is just more bang for your buck every time. I also think not dumping fuel all over the place would help if even just a little bit. Isn't that part of the reason multi point is better then tbi and sequential multi point is better then both? DI is like the next step in the chain if you ask me. Better use, better atomization, better comp, cooler temps etc it all equates to better mpg as well as low end power as I see it.

 

There are some problems I have been thinking about but they don't involve control or execution but actually physical dimensions. Taking one plug out drops compression quite a bit and any direct injector isn't going to sit as far in or displace as many cc's. That coupled with a hemi style head where valve clearance is already tight I think could pose a problem.

[datzenmike]

Here's a Z head. The plugs don't stick into the CC anynore than an L head:

 

http://i138.photobucket.com/albums/q251/datzenmike/L%20Z%20Heads%20and%20Motors/00770016.jpg[/img]"]

[72240z]

Ya but the rated compression counts on there being 2 of them not one. Know what I mean?

 

I bet one could weld a nice lip around the back edges of the plug holes, then groove them lol. So I guess not a prob after all.

[datzenmike]

OK here's a 4 plug head. The tip of the spark plug is virtually nothing plus there is space up inside beside the insulator tip.

 

http://i138.photobucket.com/albums/q251/datzenmike/L%20Z%20Heads%20and%20Motors/IMG_0380.jpg[/img]"]

[72240z]

I know what your saying, it's prob only a couple cc. It's just I doubt the injector would sit the same way, if it sits higher thats more volume. I personally would grind down the protruding nub that surrounds the stock plug so the injector would have a better spray pattern.

 

 

Thats all moot if the injector can sit low as the spark plug with no gap. I say just to say, maybe its nothing...

 

On a side note I remember were were talking about grooves on a z head and how there is not really a quench area. What do you think of welding a lip behind those injector bungs? Like half moons. I like it lol.

 

I use a trackball so lol excuse how hacky it is.

[ratsar_nx]

It definitely looks doable...

The most time consuming part would probably be fine-tuning the ECU so that it runs properly throughout the RPM and temperature range. If done right, varying the fuel pulse volume and timing as well as spark timing could possibly give you similar advantages to VVT

 

...now there's a harebrained idea: finding a way to retrofit VVT to an old Datsun head :D

[72240z]

Start a thread for that, I have ideas lol.

[hang_510]

Why would it take a new head?