Torker II MPFI Build

Was bored and decided to start on a B motor MPFI build. Here are pictures of the Torker II.

Looks good! What are the tube sizes?? I've been thinking about trying the same thing for a small block.

Robbie - the OD is 7/8th's, The Torker runners are a bit tight but it will work for what I am doing. I used a CNC machine and not a drill press like most have. This bit of precision helped me identify the exact location of the injectors so when I do the fuel rails I can locate the bosses easier.

Will you port the runners so only the very tip of the injector protrudes?

This is cool! I want to do the same modifications to an offy b motor tunnelram bottom and put a single throttle body facing forwards. I have a single quad top to change to that arrangement. Hopefully would fit under a small hood scoop. Will be following this thread.

Kit - From all the research it says not to shave then tubes. Engineers state these tubes are cut to this length to provide the best fuel atomization. With that said there is a lot of debate on the angle you put them in or "angle of incidents" and depth. I was looking for budget with performance and learning. Once I actually touch, see and play with, I will get a better understanding of how to spend......

mischief - A tunnel ram is a great idea, if you have the part best way to go, your just pulling air. The angle connecter you speak of made by Edlebrock is for adapting throttle bodies to 4150 spreads. I am looking at a 4150 style TB but did put a lot of debate between the two, there are pros and cons for both. My goal is as much airflow as possible/practical.

and robbie - ID is the .590 size, I believe this is the most common size injector out there? Really researching this area, again on a budget and a bit of a learning curve, but looking for about 550 HP on a pre-built engine was built to other specifications, trying to match application which best fits all around - about a 42lb injector what I am looking for

Holley makes a "high ram" mpfi intake for other motors. Looks just like a tunnelram but the plenum is closed on the top and has a forward facing tilted down a bit throttle body. I will most likely cut the top off and reshape it a bit and run the appropriate size bore throttle body off a new vehicle. I have the b motor offy tr with single quad top and a spare single quad top to modify.

I can imagine that there will be good turbulence at the injectors, but flow may be reduced. The top of the manifold at head is a critical spot. I am most familiar with injectors setup to point at the base of intake valves and protrude very little into the flow. Bosch injectors have a cap design to help preserve the conical pattern.

If your leaving the bung full length...I would be curious what injector you have chosen.
There are many types with varying spray patterns.
if a standard conical spray I would be concerned with it just dripping down the sides of the bung. kind of defeats the whole reason they atomize the fuel.

There are some that shoot a stream and that may work fine to get the fuel into the air as it flows past.
Then you have the protrusion into the air flow. That is just reducing the CFM flow of the runner.
Most talk about the advantage of dry over wet runners in the extra CFM of air in the dry with no fuel vapor to take up space.

I try to run mine so the tip is flush or just above the runner ceiling.
But I mostly run a standard conical spray pattern.









V8 with Ford injectors, they have a longer tip.

I used to do research in liquid sprays. At one conference in the early 1990's, a Phd student working on a GM project presented research on spraying far upstream in the intake runners, for more time to vaporize the gasoline. I recall no noticeable improvement in performance or emissions.

Not sure how or why they started spraying at the back of the intake valve. It likely started with the earliest mechanical fuel injection systems, perhaps for reasons unrelated to vaporization, and now lost to history. I doubt they try to spray thru an open intake valve since the valve is open for only a small part of the spray's duty cycle, except at idle. Though, minimizing idle emissions is important. Spraying at the hot intake valve helps vaporize fuel, but fuel drops would likely hit the valve backside anyway on their way to the cylinder. My guess is there hasn't been a lot of research and it doesn't make much difference how you spray the fuel into the intake runner. The most important thing is getting the fuel evenly distributed between the cylinders, which is what MPFI excels at, as long as all the injectors stay matched in flow.

BillG - I think you hit exactly my intent, creating match flow, all else exceeds what I have to offer, this is a science experiment.

Bill USN - Yes, I am looking at the Ford Racing injectors, 47 lb, they are the lowest cost on the market I can find, Looking at the EV6 type, but they have the EV1 as well

All - Here are the bungs welded in

very cool!!!

Isnt there already a BBM port injection manifold already available?

MP - There are very few, the first that come to mind is the Edlebrock Victor, which comes on high and ends high, and there kit manifold which looks cool, but requires a throttle body - On both the cost is about $400. This is a for a B motor, however B or RB, pickings are thin

I was looking at angles to set my /6 injectors at. I got a crazy vaccum port smack dab in the middle of where I wanted to mount the #6 injector. I was looking and found a post that said if you put the injectors a little farther upstream, you get better high RPM performance, also that the injector tips are designed to be "up the tube" as far as 1/4 inch for venturi vacuum across the runner... Who knows, I think the very close injectors help in emissions and metering, and shooting at the back of a CLOSED hot valve is for fuel vaporization. Rarely do the injectors pulse at an open valve as many are still batch fired, although its not 1 channel but 2 or 4. Even the old batch fire guys claim there is no performance gain in MPFI, just maybe a tad better idle and tighter emissions but it is just opinion.

Pishta - thanks, seems some of the information I have read as well. I debated moving mine up the runners however on this one it was easier for me to put them where I did.

And - I am going with FAST 65lb injectors, found em cheap and they fit what I need.

Here is some more Megasquirt variable setup stuff on injector timing to an open valve: forget it above 2300 RPM! There is just not enough time to inject enough fuel above 2300 RPM into an open intake valve. Larger injectors help, but its a pipe dream to think you can do this 100% of the time.

".....However, sequential injection does not necessarily mean you are injecting into an open intake valve all the time. The intake valve is only open less than 30% of the time in a typical 4 stroke engine. Once you are trying to produce more than about 25% of maximum HP your injectors are firing for longer than the intake valves are open. If your maximum HP is correctly calibrated to a safe 80% duty cycle, your injectors are injecting well over 50% of the time on closed valves.

At higher rpms, it becomes increasingly difficult to inject while the valve is open. For example, if your Req_Fuel = 15.0 ms, and your maximum duty cycle is 85% then the interval between injections cannot be closer than 17.6 ms. The time available to inject during the entire 4 stroke cycle is:

timecycle = 120/RPM
the intake is typically open for less than 240° of 720° in an engine cycle in a hot street engine, about 1/3 of the time for a complete cycle. So:

timeinject = 40/RPM
and

RPMmax = 40/timeinject
Using the numbers above,

RPMmax = 40/0.0176 = ~2300 rpm
Above this RPM, it is not possible to inject the entire amount fuel through the open valve at 100% VE and 100kPa. At idle, however, VE may be 30%, and kPa might be 35 kPa, yielding a pulse width of ~1.8 milliseconds, which certainly could be injected during the intake valve opening. So sequential injection is primarily effective at idle, and not much different from batch injection as pulse widths get larger at higher engine speeds and loads.

In any case, when fuel is injected while the valve is closed, it will simply stay in the port until the valve opens. In some cases, this period of time may allow enough heating of the mixture to better vaporize the liquid fuel, improving efficiency and emissions..."


I understand that is the best place to mount the injectors, like where else would you put them? In a pinch, I suppose you could make a 1" spacer under the TB and add 2 injectors per side ala Wilson "V-power" and bank fire them but they would have to be pretty big for a warm V8. like 4 X 54 lb/hr for a 450 HP motor (taking the 8 X 27 lb/hr injectors from a Edelbrock system) Looks good. I hope I can get mine as angled and not straight in.

An idea for best low-end torque and mileage, but still have high power is to use small MPFI injectors at each cylinder (for normal driving), with additional throttle body injectors that come on when you step on it. The later could be a factory-type TBI (GM Rochester or Holley Pro-jection) or a TBI that uses MPFI injectors (FAST, Motorvation, ...). I imagine the manufacturers don't do that because of extra cost. Most drag racers don't care about low rpm performance since they rev the engine with the brake on to launch. However, for a daily driver with performance ability it might make sense, or for rock crawlers. Of course, it would need a custom controller like Megasquirt.

Bill - I do like the dual injector theory, I think if I was more advanced I would do this. Right now I am going with FAST 65lb injectors, megasquirt 3, wideband, etc...... I think I will be using the DIY throttle body, it flows 1215 cfm, but I could be swayed at any time based on good intel. I really started this project since I was having problems tuning my Demon and wanted to go to a Dominator - The paths we take