Injector, fuel pressure. BMW 325 m50b25

For discussing injector selection,manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
Forum rules
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.

If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).

If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days

The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
Kornel
MegaSquirt Newbie
Posts: 3
Joined: Mon Oct 22, 2007 10:15 pm
Location: Poland

Injector, fuel pressure. BMW 325 m50b25

Post by Kornel »

Hello. My car is BMW 325 (m50b25 without vanos). I'm fairly new to the forum and am in the process of gathering hardware and info to convert my stock ecu to MSII v.3 (fuel and spark). Now the car is NA, but in future i want FI (turbo,about 15-20 psi,of course with forged pistons and lower compression). For spark I'm planing to use EDIS 6 with 36-1 wheel, for fuel 6 cycle altering. I have already read few posts about Simultaneous or Alternating but I don't find answer to my questions. The ignition order is 1-5-3-6-2-4. My stock injectors are about 20 lbs/hr , i don't know exactly but it makes 192 hp at flywheel. Stock fuel pressure is 43.5 psi. I use a calculator from megasquirt site and for my stock injectors i get Downloaded Req_Fuel 4.4 ms(according MS FAQ it should be less than 12-15 but more than 8ms), so it is to low. OK, i changed Injector Flow to 11 lb/s get Req_Fuel 8.1 ms. To get 11 lb/s the fuel pressure should be 13.2 psi, I don't think this will work. I have read already about 2:1 and 4:1 FMU, are they a solution for my problem???when FI which injectors should i buy?? I'm planing get around
350-400 hp on wheels.

Ps.Sorry for my English, I'm from Poland.
Kornel
MegaSquirt Newbie
Posts: 3
Joined: Mon Oct 22, 2007 10:15 pm
Location: Poland

Post by Kornel »

Thanks for your reply. With 1 cycle simultaneous or 2 cycle alternating I get req_fuel 13.3 ms on stock injectors, it seems correct:) I have already read some posts and people say that with 2 cycle alternating they have got problems with good response to gas pedal and smooth engine running.Is this true?? what is better 1 cycle simultaneous or 2 cycle alternating (I need good take off and engine response)??
Kornel
MegaSquirt Newbie
Posts: 3
Joined: Mon Oct 22, 2007 10:15 pm
Location: Poland

Post by Kornel »

Good piece of information:) Thanks
Post Reply