I was reading through the Steedspeed intake manifold thread and everyone is gung-ho on a direct port meth injection, regardless of their experience or background with the different setups. I figured I would offer my experience (for whatever it's worth) in a new thread instead of cluttering steedspeed's thread.
I used to run a pre-throttle body fuel injection setup using the smt-6 (mpi) tuner. I ran 2 "blue giants," each rated at 440 cc/min and had them spraying into the cold-pipe about a foot from the throttle body. Fuel injection pressures vary, however they are usually set at roughly 43 psi and can build 1 psi for every pound of boost the engine sees. Regardless of differing opinions on this setup, I had zero issues with equal fuel distribution. I checked my plugs countless times and each plug always looked identical to one another. I had no misfires or any other issues. When I broke the engine down for a rebuild, everything was in great shape.
Now consider placing a methanol injector in the cold-pipe (pre-throttle body). These injectors run on a pressure ranging from 150 psi to 250 psi (depending on the quality of pump you are using). I am running at a peak pressure of 200 psi with my labonte motorsports setup. With such high pressures, the methanol/water mixture atomizes so well that distribution will not be an issue. Comparing to the fuel setup, I was having no issues at lower pressure with a fuel injector that was designed to spray into the engine and not a hard-pipe, but it still worked without a hitch. Now consider a meth injector that sprays at a much higher pressure and uses a spray pattern designed to "fog" unlike a fuel injector.
Awhile back, I spoke with Dan at labonte motorsports (I believe he is the owner). We had a discussion about whether I would benefit over a pre-throttle body setup with direct port injection. From his experience, he said that as long as each cylinder is receiving an equal distribution of air (i.e. the manifold is designed properly), then the highly atomized methanol will have equal distribution as well.
Failsafes are another aspect to look at. Consider running 1 meth injector pre-throttle body. I am running a failsafe that requires me to be above a certain methanol threshold (an injection flow rate) in order to run a higher boost pressure than what my wastegate pressure is set at. If I don't inject a certain amount of methanol, I can't boost over waste-gate pressure or damage my engine from a lack of methanol at high boost conditions. Also, if my injector were to clog during a higher boost condition, the failsafe would immediately return me to waste-gate limited pressure. By having 1 injector, the injection of methanol or the lack of injection gives the failsafe easier "interpretation" of whatever rate of injection I am at. Flow rates are dependent on one injector, not 4. 1 injector gives the setup 1 point of failure.
Now consider running 4 meth injectors (1 per cylinder). You now have 3 additional points of failure (4 total). 1 nozzle could clog resulting in a cylinder thinning out and subsequent damage occurring. If you are monitoring a methanol gauge, you will see a drop in the flow rate. Yes the drop will be an indicator, but the drop will be less significant and more difficult to notice. If you are running a failsafe similar to my setup, then that drop off in one injector may not be enough for the system to realize that there is a failure and waste-gate limited boost would not be activated.
Overall, assuming a proper manifold design giving equal air and equal meth/water distribution to each cylinder, a single pre-throttle body injector setup has less points of failure, a much simpler design, allows the failsafe to easily do its job, and has a lot fewer connections (fewer sources of failure).
I have been running a 1 injector pre-throttle body setup and put down ~300whp and ~310 wtq pushing 18 psi on a dynojet. The ambient temperature was 105 degF (texas summer!). Also worth mentioning, my J and S was quiet as a mouse (i.e. no detonation).
I used to run a pre-throttle body fuel injection setup using the smt-6 (mpi) tuner. I ran 2 "blue giants," each rated at 440 cc/min and had them spraying into the cold-pipe about a foot from the throttle body. Fuel injection pressures vary, however they are usually set at roughly 43 psi and can build 1 psi for every pound of boost the engine sees. Regardless of differing opinions on this setup, I had zero issues with equal fuel distribution. I checked my plugs countless times and each plug always looked identical to one another. I had no misfires or any other issues. When I broke the engine down for a rebuild, everything was in great shape.
Now consider placing a methanol injector in the cold-pipe (pre-throttle body). These injectors run on a pressure ranging from 150 psi to 250 psi (depending on the quality of pump you are using). I am running at a peak pressure of 200 psi with my labonte motorsports setup. With such high pressures, the methanol/water mixture atomizes so well that distribution will not be an issue. Comparing to the fuel setup, I was having no issues at lower pressure with a fuel injector that was designed to spray into the engine and not a hard-pipe, but it still worked without a hitch. Now consider a meth injector that sprays at a much higher pressure and uses a spray pattern designed to "fog" unlike a fuel injector.
Awhile back, I spoke with Dan at labonte motorsports (I believe he is the owner). We had a discussion about whether I would benefit over a pre-throttle body setup with direct port injection. From his experience, he said that as long as each cylinder is receiving an equal distribution of air (i.e. the manifold is designed properly), then the highly atomized methanol will have equal distribution as well.
Failsafes are another aspect to look at. Consider running 1 meth injector pre-throttle body. I am running a failsafe that requires me to be above a certain methanol threshold (an injection flow rate) in order to run a higher boost pressure than what my wastegate pressure is set at. If I don't inject a certain amount of methanol, I can't boost over waste-gate pressure or damage my engine from a lack of methanol at high boost conditions. Also, if my injector were to clog during a higher boost condition, the failsafe would immediately return me to waste-gate limited pressure. By having 1 injector, the injection of methanol or the lack of injection gives the failsafe easier "interpretation" of whatever rate of injection I am at. Flow rates are dependent on one injector, not 4. 1 injector gives the setup 1 point of failure.
Now consider running 4 meth injectors (1 per cylinder). You now have 3 additional points of failure (4 total). 1 nozzle could clog resulting in a cylinder thinning out and subsequent damage occurring. If you are monitoring a methanol gauge, you will see a drop in the flow rate. Yes the drop will be an indicator, but the drop will be less significant and more difficult to notice. If you are running a failsafe similar to my setup, then that drop off in one injector may not be enough for the system to realize that there is a failure and waste-gate limited boost would not be activated.
Overall, assuming a proper manifold design giving equal air and equal meth/water distribution to each cylinder, a single pre-throttle body injector setup has less points of failure, a much simpler design, allows the failsafe to easily do its job, and has a lot fewer connections (fewer sources of failure).
I have been running a 1 injector pre-throttle body setup and put down ~300whp and ~310 wtq pushing 18 psi on a dynojet. The ambient temperature was 105 degF (texas summer!). Also worth mentioning, my J and S was quiet as a mouse (i.e. no detonation).
