KZ650 C2 Fuel Injection Conversion

I was out doing some work on my lathe so decided I would modify the Ford injectors to take a 5/16" fuel injection hose.

Here are the stock injectors setup for a fuel rail (O rings on top) :



The molded plastic needs to be trimmed from the rail side enough to hold a band clamp. The steel tube is exactly .31" so does not need to be touched.





They are how ready to have a hose crimped on.

Another step closer , what sort of fuel pressure will you be running ?

Those stock injectors are flow rated at 43.5 PSI but I am not sure what the maximum output of a stock ZX6 fuel pump. As far as I could gather the ZX6 manual says 41-44 PSI but that is to be determined. I do have a adjustable regulator but not even sure how much effect it will have, its off a 914 Porsche.

At 43.5 PSI the maximum HP those injectors can achieve is 25 each. This engine will not be capable of that in its current build configuration, probably somewhere in around 85 HP total. Anywhere between 30-50 PSI to where it runs optimally, I will have a pressure gauge installed right at the regulator.

That is the crap shoot of mixing and matching non stock components, I just don't know until I start it up.

I guess ultimately HP will be determined by "flow rate" and the duty cycle of the injector pulse

Wookie58 wrote:

I guess ultimately HP will be determined by "flow rate" and the duty cycle of the injector pulse
 

Yes, that flow rate is at a normal 80% duty cycle you would expect in a street application, you could turn it up higher to race spec (95%) but that just creates extra heat for not much more HP gain (4 HP per injector) There are plenty of tuning options on the fuel and spark maps stored in the ECU.

Once I get the engine built I will probably run it on carbs for the initial break in, that way I can take my time tuning the injection.

Wet and miserable out so decided to bolt the injectors onto the throttle body in my office.



Cut and crimped one outside supply line so I can see how badly it fouls with the petcock when installed. I cut the hose to 4" which I think is plenty to see where the GPZ fuel rail will sit. Once I establish the optimal location I will cut the rest to match as I may end up trimming some length off.



I have a Pingel petcock that I am using on this build and will be fabricating a custom mount plate so I can mount the petcock anywhere between the stock tanks 43mm bolt locations.

Will try to dublicate your fuel injection conversion, have multiple sets of all GPZ 1100 UT (ZX1100A) injection parts.
But have to finish my frame, wheel and the 530 chain coversion on my Z1 first.
My buddys HD WP USD fork/brake conversion also took a lot of my wrenching time i don´t have....

 

 

I started looking at this project again the other day.

I checked the volume of the air box I designed as it is a lot smaller than I would like due to the location of my auxiliary fuel tank.

I read somewhere that Cosworth Racing did some R&D on air box design that found a efficient air box volume was equal to 12 X engine displacement. According to this my air box will be restrictive due to a low volume as I am about 1/3 of there "recommended" size.

The one thing I do know is that a restrictive air box is sometimes preferred over individual pod filters due to many factors. This generally depends on how the engine is going to be used. Since this is a street bike, and not an all out race bike, this restriction may be acceptable especially since the fuel injection can "learn" to tune around its limitations. The only down side may be slightly higher fuel consumption.

I still need to look into it closer but would still prefer the air box over the pods if I can help it.

Injected wrote:

I started looking at this project again the other day.

I checked the volume of the air box I designed as it is a lot smaller than I would like due to the location of my auxiliary fuel tank.

I read somewhere that Cosworth Racing did some R&D on air box design that found a efficient air box volume was equal to 12 X engine displacement. According to this my air box will be restrictive due to a low volume as I am about 1/3 of there "recommended" size.

The one thing I do know is that a restrictive air box is sometimes preferred over individual pod filters due to many factors. This generally depends on how the engine is going to be used. Since this is a street bike, and not an all out race bike, this restriction may be acceptable especially since the fuel injection can "learn" to tune around its limitations. The only down side may be slightly higher fuel consumption.

I still need to look into it closer but would still prefer the air box over the pods if I can help it.

I think this is one of those "ideal" numbers that is likely to be unachievable with most vehicles. If you think a 1000cc bike would need an airbox the size of three 4ltr oil jugs and a 5.0 mustang would need an airbox as big as the gas tank in most European cars !!!!! I'm sure you can come up with a free flowing airbox that will do the job

wrote:

wrote:

I started looking at this project again the other day.

I checked the volume of the air box I designed as it is a lot smaller than I would like due to the location of my auxiliary fuel tank.

I read somewhere that Cosworth Racing did some R&D on air box design that found a efficient air box volume was equal to 12 X engine displacement. According to this my air box will be restrictive due to a low volume as I am about 1/3 of there "recommended" size.

The one thing I do know is that a restrictive air box is sometimes preferred over individual pod filters due to many factors. This generally depends on how the engine is going to be used. Since this is a street bike, and not an all out race bike, this restriction may be acceptable especially since the fuel injection can "learn" to tune around its limitations. The only down side may be slightly higher fuel consumption.

I still need to look into it closer but would still prefer the air box over the pods if I can help it.

I think this is one of those "ideal" numbers that is likely to be unachievable with most vehicles. If you think a 1000cc bike would need an airbox the size of three 4ltr oil jugs and a 5.0 mustang would need an airbox as big as the gas tank in most European cars !!!!! I'm sure you can come up with a free flowing airbox that will do the job



 

Yes I agree, for a 750cc engine like what I am using it on it comes out roughly to 9 liters which is half the size of a KZ650 gas tank. I am not even sure what the volume is on the stock air box but I should be able to figure that out.

I have mine designed as big as I could physically fit in the available space. With the filter panel and opening on the bottom I am drawing air in like the stock air box just flipped around. The rubber ducts that attach the throttle bodies to the air box are stock KZ650 #2 and #3 which fit the GPZ1100 throttle bodies perfectly.

 

One key thing I did discover when I went back and looked at it is I can add a lip with a radii on the inlet hole to increase CFM potential. Currently it draws in air over a sharp edge.

The early KZ650 air box for 1977 to 1981 models (pre CV carb) has a approximate volume of 5.3L without the air filter and 4.5L with the air filter. Much less than the Cosworth formula.

The later CV air box used for both KZ650 and 750 is slightly smaller using a shorter air filter.

The draw length for the air to travel from the inlet lid to the carb ducts is approximately 8" as measured on the center line.

Its a rainy cold day here so have been in the office making some CAD revisions.

Below is where I had stopped on the air box development shown from the bottom, the light blue is filter foam sheet. I just had the inlet openings milled with a sharp edge.

 

I mounted some shallow hollow boxes (yellow) to be able to mount turned velocity stack rings (orange) Everything is 6061 aluminum, the rings are 1-1/2" Schedule 40 pipe which has a 40mm ID. All of the other sides of the box are closed off solid.

 

The addition of the mount boxes and velocity rings give me a extra 1" of draw length.

This air box that is designed around available space but is about 1/2 of the volume and draw length of a stock air box. I am just going to have to see if this will be acceptable as the only alternative would be to run pods filters.