123quattro

Hi Richard,

How much power are you expecting to make? Two 044s is a lot of pump. 1 would probably support all a 2.9L blower can do. I would think you could do single injectors per cylinder to simplify your runners as well. You should be able to get a nice solid idle with Deka 80s. Those would be good for 1000hp.

http://realstreetperformance.com/sto...on-test-5.html

blau928

Hi Tony,

That was the only way to fit the SC snout for it to blow up side down... Actually, the reverse flow system I sketched will solve this and delete the water bridge.. But, too much to do now...

blau928

Hi 123,

500 RWHP is the minumum, and then up from there..

The 2 Bosch 044's is just a safety precaution for the upper limits..

I have a single injector per cylinder pattern in CAD, and will make one setup with it just to use the LH for testing etc. The dual injector is for better fuel distribution and atomization. I have no problem to control these, as I now have a Motec M8 again. The use of 2 injectors per cylinder in a 4 valve head improves BSFC and lowers the amount of fuel needed in my research. It also solves puddling in the runner, and allows a lower fuel rail pressure than boiling the fuel which I am sure many are doing with the really high pressure in the rails that some are running in their systems..

Once the current 5 liter in the car is done, I will test it to the limit and see where it's limits are. I have a spare motor with 60k miles sitting in the garage, and will rebuild the current motor to a 6+ Liter motor with different cams to advance more things in future..

Think of it as a long term never ending thing that allows an oddball guy like me to exercise his brain..

Hope that answers your questions..

Best Regards,

Imo000

How much experience do you have boosting engines?

blau928

At least 15+ years toying with motors... Turbocharged, supercharged, and normally aspirated.

123quattro

You can get injectors with split spray patterns specifically for injecting into 4 valve heads. Also, those Deka 80s rated for that flow at something like 40psi. You don't have to run crazy rail pressure to get the flow.

blau928

Hi 123,

I undersand your point on the Siemens-Deka injectors.. However, I want to have more accurate control over the fuel trim and atomization.. In addition, the injector placement with two injectors per cylinder (in my opinion, and in discussion with some engineers I had a chance to chat with) allows for better atomization than a dual pattern single injector. Of course there are other variables like distance to valve, charge velocity, manifold pressure and other things to take into consideration as well. However, I am choosing the dual setup for very specific reasons that many people do not seem to understand.. But that's quite ok by me, and no offense to them..

(It's sort of the analogy of a finer mist with two small 1 inch garden hoses with spray nozzles and a 2 inch fire hose with a spray nozzle.. My 2 cents is on the garden hose mist being of a more fine spray than the fire hose if both hoses have the same hose pressure.

You can calculate this out with fancy equations, but it is something I have been wanting to try on this project for many years, actually the system was designed for it in the beginning many years ago when I first sketched the plans.

(FYI, the Ford GT uses dual inj/cyl, as well as some other funky engine makers. Nissan has found in their testing, the the BSFC of their test motor went down by a great deal when doing this in a study they did last year.)

Maybe I can try the Siemens-Deka ones in the single injector/cylinder setup with the LH. However, I don't want to go more than 42# on a single..

Anyway, I appreciate your input, and thank you for the suggestions, as I am always curious about learning new and or different approaches to solving these puzzles. This is also why I would love to see all the data logs for all the "boosted" 928's out there. Then we can all see who is doing what to solve the various problems that cause detonation...

Guess that's the geek in me....

123quattro

The turbo LS Camaro I built used two pumps. I kicked the second one on with a Hobbs switch at 2psi boost referenced from the intake manifold.

blau928

Hi 123,

Thanks for the note. I was discussing this exact setup with George earlier. However, as I was telling him, I believe that I have an output port free on the Motec that I should be able to use for the second pump.. (I prefer to use the ECU, as I can program some saftey or warning bell to let me know if the fuel pumps don't activate or fail etc.. It is an M8, so very similar to an M880)

I still have to decide on the lines I wish to use, I may plumb in an AN-10 return with two An-8 feeds with a couple directional valves to equalize rail flow and pressure etc. once the second pump is on. I have to check, but I think the strainer on my pump line is already attached to an AN-10 fitting when I changed the fuel pump to an 044 pump a few years ago, so I can easily attach a Y fitting on the filter line from the tank.

(All to be sorted later while the CAD stuff is being milled. Now I need to get the car running to test the new oil coolers, radiator, vacuum pump, provent, water bridge and other components before I leave for my trip next friday..)

blau928

Hi Bill,

I will agree to disagree with you on the point of compressing the fuel does not boil it, and the heat comes from the recirculation and the engine compartment. Gasolene boils at about 98 degrees (goes from liquid to gas)

I am not a degreed engineer, but I do know that all matter heats up when compressed because the molecules are bumping into each other in a smaller space, and this is what causes the increase in heat. This is true for the air in a supercharger and turbo as well as any compressor, when you compress air, it gets hotter.. (If you don't believe me, go touch the end of a bicycle pump by restricting the flow and tell me it is not hot...) Absolutely not from anything else, the heat is from compression alone...

Same with metal or any matter... Don't remember the technical physics term for it, but any physics or engineer can confirm this.

Bill, as you note correctly, the flow through the fuel pressure regulator is most at idle, and the fuel will bypass only at idle. When the car is driving, the fuel will go to the cylinders, and not to the tank. The diaphragm in the FPR will open under vacuum and allow the fuel back to the tank. This is why it is recommended that one should have a big return line with a big pump so at idle, the fuel does not boil from being pressurized in the return line.

In addition, hotter fuel will lean out the charge in the cylinder due to it occupying more volume space than colder fuel, which means that you can have more cold fuel in a space than hot fuel as more fuel molecules occupy a smaller space due to the molecules not moving around as much.. (Thats very technical, but just physics as well. I hope that the people here undersand what I am talking about, as I may not be doing the best job explaining this stuff....)

To add to the confusion, when you move to a direct injection system where the fuel is injected directly into the combustion chamber, the use of high pressure injectors is needed... I have not done research on the DFI systems yet, so I can't comment there.

On another note, pressure is inverse to flow, so because the pressure is down, it does not mean that there is not enough flow for the power level being supported. Granted, the injectors are calibrated for 43.5 PSI and base pressure is usually around 40psi in the rail. Raising the pressure higher overdrive the injectors, and you lose control of the fuel trim. At high altitude, the issue may be that there is an inlet restriction to the pump. If there is an in tank filter, it could be clogged and cause the the pressure to drop, as the pump has to work harder at higher elevation because the weight of the earth's atmosphere is less at 7000ft. than at sea level. It most certainly will not be 14.7 psi like at sea level, and cannot push the fuel into the pump. the pump has to suck it in more at 7K elevation than at sea level, so the fuel rail will lose pressure in it because the pump is working harder to get the fuel from the tank......

Granted, I do not have access to all the data on George's car, and I can only make an educated guess based on what you guys have told me.

However, I am very clear about pressure causing heat, and the thermal management is the entire basis for building this setup.

With all due respect Bill, I will still buy you a beer, but I am certain about the heat issue.. If I am misunderstanding you, please let me know..

123quattro

Gasoline DI is a totally different animal and not really related to port injection. DI runs at 200+ bar vs ~3 bar for port injection. The fuel pump is generally driven via the camshaft. You also shoot the fuel onto the crown of the piston and bounce it towards the spark plug.

Imo000

So if a compressed metal heats up then a streched metal will cool down? I don't think so. There is way too much theory in this project and not enough real world testing. Dual imjector to spray each port....this is good in theory but when transitioned into the real world, will there be any measurable difference? Don't over complicate thigs just because it sounds good on paper.

ptuomov

With Sharktuner 2, the single 60 pound injectors work just fine.

blau928

Wow! 200 bar! Interesting... The part about bouncing off the piston crown makes sense, as then it also vaporizes better and the plug has an easier job of ignition.. I wonder if it probably also cools the piston crown..?


Thanks, I did not know that about DI..

blau928

Hi Tuomo,

That's what John Speake said both when I visited him, and again recently..

Again, I want to try this and see what happens in my setup.