Fuel Injector Spray Pattern
Posted: Sun Feb 17, 2019 10:29 am
Hey Guys,
Have you thought about what injectors to use? I've had problems with the Bosch 947 injectors (4 holes) 24 lb/hr. At 2000 rpm and above it suddenly becomes overly rich and I have to reduce the fuel map by 20%. I then mistakenly buy a set of Dodge Dakota V6 (1998) injectors rated at 21 lb/hr. This one is better. Single hole, disc type nozzle, but the hole was not at the center. Hmmmmm....... so this ran a lot better but requires a LOT more fuel in the map! But it didn't have the problem of going rich at 2000 rpm. But by 4000 rpm I had to have the fuel map at 90, which is almost maxing out the injector. So the flow rate or the nozzle type doesn't seem to work for the 3.2 engine with cams.
I then started to look at other bosch injectors. The CF2 GTV V6s have the EV1 0280 150 701 single hole pintle style nozzle injectors and the 156 GTA has the 0280 156 038 injectors EV4 4-hole disc nozzle. Flow are both about the same. But it looks like the 986 Porsche Boxster has a twin hole design. I think that will spray nicely to the two intake tracts for each cylinder.
If you have a single cone it and stock heads, the spray will hit the separator where the intake tract splits to go to the 2 intake valves. Might be ok for the V6 12V engine. If you modify the heads and re-shape the separator, then a single cone spray might work well. These is just my hypothesis. For a road car, the injector hole numbers (more the better) will be good. It will improve cold start and maybe give a slight advantage in terms of improved mpg. For a track car I don't think there will much of a benefit. Although I just can't think of how a single spray cone spraying into the separator is a good thing.
I have some youtube links below showing why some older injectors meant for 2 valve engines wont work well with 4 valve engines: Remember the 4-valve engines have split tracts once it gets close to the valves.
E30 BMW 2-valve injectors
https://youtu.be/Q87ZVkzTPME
E46 M3 BMW 4-valve injectors
https://youtu.be/hQBkB7YKjzo
Have you thought about what injectors to use? I've had problems with the Bosch 947 injectors (4 holes) 24 lb/hr. At 2000 rpm and above it suddenly becomes overly rich and I have to reduce the fuel map by 20%. I then mistakenly buy a set of Dodge Dakota V6 (1998) injectors rated at 21 lb/hr. This one is better. Single hole, disc type nozzle, but the hole was not at the center. Hmmmmm....... so this ran a lot better but requires a LOT more fuel in the map! But it didn't have the problem of going rich at 2000 rpm. But by 4000 rpm I had to have the fuel map at 90, which is almost maxing out the injector. So the flow rate or the nozzle type doesn't seem to work for the 3.2 engine with cams.
I then started to look at other bosch injectors. The CF2 GTV V6s have the EV1 0280 150 701 single hole pintle style nozzle injectors and the 156 GTA has the 0280 156 038 injectors EV4 4-hole disc nozzle. Flow are both about the same. But it looks like the 986 Porsche Boxster has a twin hole design. I think that will spray nicely to the two intake tracts for each cylinder.
If you have a single cone it and stock heads, the spray will hit the separator where the intake tract splits to go to the 2 intake valves. Might be ok for the V6 12V engine. If you modify the heads and re-shape the separator, then a single cone spray might work well. These is just my hypothesis. For a road car, the injector hole numbers (more the better) will be good. It will improve cold start and maybe give a slight advantage in terms of improved mpg. For a track car I don't think there will much of a benefit. Although I just can't think of how a single spray cone spraying into the separator is a good thing.
I have some youtube links below showing why some older injectors meant for 2 valve engines wont work well with 4 valve engines: Remember the 4-valve engines have split tracts once it gets close to the valves.
E30 BMW 2-valve injectors
https://youtu.be/Q87ZVkzTPME
E46 M3 BMW 4-valve injectors
https://youtu.be/hQBkB7YKjzo