Injectors
04-03-2004 | 12:08 AM
#1
Thread Starter
Drifting
Joined: Feb 2003
Posts: 2,254
Likes: 0
From: Akron, Ohio
Injectors
I know many people have brought this up, but I am looking at injectors for my car to get, where is a good place to buy plus has a good injector? I am looking upgrading more to my car later so I want to make sure I don't get held down by this. If my goal is about 350rwhp someday, what kind of injectors do I have to be running? Where is a good place to buy them from? I have guru chips, 15psi, 3-bar fuel pressure; plan on all new 3" exhaust without cat, maf, plus looking at a new turbo to get me to about 350rwhp or there about.
04-03-2004 | 05:17 PM
#5
Rennlist Member
Joined: Jun 2002
Posts: 1,301
Likes: 1
From: Oconomowoc, WI
Mike, to hit 350RWHP you would need to make just a bit over 400 crankshaft horsepower (figuring in a 15% drivetrain loss). So using RC engineerings injector calculators: http://www.rceng.com/technical.htm#WORKSHEET
At 402.5 (350rwhp * .15 + that sum added back to 350) at 43.5 fuel rail pressure, with a .60 B.S.F.C (might be able to go lower with the efficiency of our engines) at a 80% injector duty cycle the recomended injector size would be 75.81lb/hr.....or just 75. I would always go a little to large than a little to small. So you might want to go with 85's...just a thought...however if you can get the B.S.F.C under .60 then the 75's will be plenty adequate.
That type of injector would fall into a low impedance peak and hold injector, hence the need for ballast resistors if you are utilizing the Motronic. High impedance injectors are referred to as saturated injectors.
Personally, I would go with the Delphi Lucas type injector either through Guru Racing (Danno has ballast resistors as well) or through Racetronix...I believe the Delphi's are on sale currently as well. The Delphi uses a 6 hole diffuser disc which atomizes the fuel much better that the radius rod (garden hose) Siemens or pintle type Bosch, et all. However, the Siemens and Bosch are still excellent injectors! Although the better atomization is a huge benefit when you are dealing with large injectors like #55's or larger at higher rpms.
Hope this helps...I just did a great deal of research myself lately on this very topic.
Take Care!
At 402.5 (350rwhp * .15 + that sum added back to 350) at 43.5 fuel rail pressure, with a .60 B.S.F.C (might be able to go lower with the efficiency of our engines) at a 80% injector duty cycle the recomended injector size would be 75.81lb/hr.....or just 75. I would always go a little to large than a little to small. So you might want to go with 85's...just a thought...however if you can get the B.S.F.C under .60 then the 75's will be plenty adequate.
That type of injector would fall into a low impedance peak and hold injector, hence the need for ballast resistors if you are utilizing the Motronic. High impedance injectors are referred to as saturated injectors.
Personally, I would go with the Delphi Lucas type injector either through Guru Racing (Danno has ballast resistors as well) or through Racetronix...I believe the Delphi's are on sale currently as well. The Delphi uses a 6 hole diffuser disc which atomizes the fuel much better that the radius rod (garden hose) Siemens or pintle type Bosch, et all. However, the Siemens and Bosch are still excellent injectors! Although the better atomization is a huge benefit when you are dealing with large injectors like #55's or larger at higher rpms.
Hope this helps...I just did a great deal of research myself lately on this very topic.
Take Care!
04-04-2004 | 03:42 AM
#6
Race Director
Joined: Jul 2001
Posts: 14,075
Likes: 3
From: Santa Barbara, CA
"If my goal is about 350rwhp someday,"
You'd need at least 65#/hr injectors to keep the duty-cycle below 80%. This will keep the injectors cooler as well as the DME transistor. Talk with the guys at RC Engineering about various mechanical aspects of different injectors. They'll confirm that the disc-type mechanism of the Lucas & Delphis are better for high-volume flow.
You'd need at least 65#/hr injectors to keep the duty-cycle below 80%. This will keep the injectors cooler as well as the DME transistor. Talk with the guys at RC Engineering about various mechanical aspects of different injectors. They'll confirm that the disc-type mechanism of the Lucas & Delphis are better for high-volume flow.