Hey Guys,
I have finally sorted my clutch out and decided it would be nice to get another project going on this car. I want to get more power out of it (around 430whp on E85 atm) but realize I am up against the cost wall on this platform. I can't afford to buy RB or Vargas turbos at the moment since that would mean not only the turbos but also the Cobb, fuel pump, and probably down pipes. Additionally that is a commitment to this car that is kind of outside of the scope of a DD. This is not my project car.
I could just turn up the boost on the stockers and run post turbo meth for octane/cooling/fuel but I am not comfortable driving the turbos that hard since they already have a little whine when cold (been running 17.5 psi for the past 30k miles). I did some research and figure that pre-turbo meth may be a viable option to lowering PWM. The concept is that the meth/water mix will suck up the heat while the turbos are compressing and thus your outlet temps will be near or slightly above ambient. Obviously air out of the turbos at 100F is a lot more dense than the 300-350F I am pushing now. Denser air takes less space, less space means each turn of the compressor contains more air, more air per turn means less shaft speed on the turbos, end result I can theoretically turn up the boost to fit within the same shaft speed window.
There are some limitations/issues here:
1. I can't measure shaft speed directly. If I had a shaft speed sensor and a thermocouple at the turbo outlet, that would be great, but that's beyond this experiment and my wallet. For this setup, PWM will be used as an approximation of how fast/hard the turbos are running.
2.Terry tested a pre-turbo/post turbo meth setup and saw no change in PWM. This is not good news for this test, but I want to try it nonetheless
3. Impingement: This is essentially erosion of the compressor wheels. This happens when the meth/water mix is still in droplet form and not totally vaporized when it hits the compressor.
Number 3 is obviously the biggest issue and I have spent some time researching and thinking about it. For this reason I have decided to go with a mechanical methanol injection setup. Mechanical methanol injection setups claim to have finer droplets than the electrical setups currently offered for the 335i. They function by using boost pressure to push the fluid into a 2-port atomizing nozzle. The other port is boost air. The boost air shoots across the liquid stream causing it to break up into a finer mix and evaporate quicker than if the methanol was injected into the air alone. That means methanol will be injected at ~17psi with ~20psi air pressure to break the droplets up.
I am not concerned about impingement for the following reasons:
1. Mechanical meth nozzles should create smaller drops
2. We already spit PCV oil into the turbos in some quantity and those drops are much more likely to be large. No erosion yet.
3. Flow is largely based on boost pressure rather than RPM. Unlike the electrical setups, flow varies with boost which should help reduce the amount of time that full meth flow is happening.
Criteria for success:
1. Nothing breaks and no meth fires
2. 500whp as measured by VirtualDyno (I am at 430whp now) in the same or slightly larger PWM window
Before we go any further, here is fair warning. This may not work out at all. This may damage turbos. I do not recommend any one to try and of this.
I will be updating this thread with my progress.
Best,
Chris
I have finally sorted my clutch out and decided it would be nice to get another project going on this car. I want to get more power out of it (around 430whp on E85 atm) but realize I am up against the cost wall on this platform. I can't afford to buy RB or Vargas turbos at the moment since that would mean not only the turbos but also the Cobb, fuel pump, and probably down pipes. Additionally that is a commitment to this car that is kind of outside of the scope of a DD. This is not my project car.
I could just turn up the boost on the stockers and run post turbo meth for octane/cooling/fuel but I am not comfortable driving the turbos that hard since they already have a little whine when cold (been running 17.5 psi for the past 30k miles). I did some research and figure that pre-turbo meth may be a viable option to lowering PWM. The concept is that the meth/water mix will suck up the heat while the turbos are compressing and thus your outlet temps will be near or slightly above ambient. Obviously air out of the turbos at 100F is a lot more dense than the 300-350F I am pushing now. Denser air takes less space, less space means each turn of the compressor contains more air, more air per turn means less shaft speed on the turbos, end result I can theoretically turn up the boost to fit within the same shaft speed window.
There are some limitations/issues here:
1. I can't measure shaft speed directly. If I had a shaft speed sensor and a thermocouple at the turbo outlet, that would be great, but that's beyond this experiment and my wallet. For this setup, PWM will be used as an approximation of how fast/hard the turbos are running.
2.Terry tested a pre-turbo/post turbo meth setup and saw no change in PWM. This is not good news for this test, but I want to try it nonetheless
3. Impingement: This is essentially erosion of the compressor wheels. This happens when the meth/water mix is still in droplet form and not totally vaporized when it hits the compressor.
Number 3 is obviously the biggest issue and I have spent some time researching and thinking about it. For this reason I have decided to go with a mechanical methanol injection setup. Mechanical methanol injection setups claim to have finer droplets than the electrical setups currently offered for the 335i. They function by using boost pressure to push the fluid into a 2-port atomizing nozzle. The other port is boost air. The boost air shoots across the liquid stream causing it to break up into a finer mix and evaporate quicker than if the methanol was injected into the air alone. That means methanol will be injected at ~17psi with ~20psi air pressure to break the droplets up.
I am not concerned about impingement for the following reasons:
1. Mechanical meth nozzles should create smaller drops
2. We already spit PCV oil into the turbos in some quantity and those drops are much more likely to be large. No erosion yet.
3. Flow is largely based on boost pressure rather than RPM. Unlike the electrical setups, flow varies with boost which should help reduce the amount of time that full meth flow is happening.
Criteria for success:
1. Nothing breaks and no meth fires
2. 500whp as measured by VirtualDyno (I am at 430whp now) in the same or slightly larger PWM window
Before we go any further, here is fair warning. This may not work out at all. This may damage turbos. I do not recommend any one to try and of this.
I will be updating this thread with my progress.
Best,
Chris