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West_Racing
07-05-2008, 06:30 AM
I have this setup on a 408ci BBC. The engine has the performer RPM aluminum heads and a .600" lift hyd. roller cam. (230 degrees @ .050" lift). This cam was ground for my combination. The engine has a true 10.5:1 static compression. The exhaust starts out with a custom built 2" to 2 1/8" stepped header. (about 36" to 38" primary lengths) This goes into a 3.5" collector and then runs through a 3" exhaust system and 3" big block series flow master mufflers. (the quieter ones :) ). The fuel injector chip was sent to me for this combination. The vehicle is a Toyota Landcruiser (looks like a jeep for those who don't know). It is an automatic with 5.29:1 gears and 39.5" tires.

OK; I think that generally covers my combination. Now to the injector question. (note: This engine was carburetor before so I know there is no issue with its running.) I have had to work hard to get this thing to run right. I have it where it will idle good, and throttle good. If you hold the throttle open in neutral it will start popping in the exhaust, if it is in gear it goes rich and surges like an injected blower engine. Could this simply be that at low rpm my engine wants smaller injectors? This is my present guess, but I do not want to spend $400 to $500 to just test this idea. (note: I plan to turn the engine up to about 6300 rpm.)


If someone can give me some insight into this EFI it would be greatly appreciated. I have years of race engine building experience. But the EFI stuff is new to me. I am very good with computers and electronics, so there is not much concern for tuning up the software side of this system. I just feel that right now I have a mechanical injector size issue?

Thanks; John

shaun callaway
07-07-2008, 07:25 AM
What EFI system are you using?

West_Racing
07-08-2008, 10:52 AM
I have a 3550 pro-flo multi port system. (The one with the larger injectors, & HP range)

S. Armish
07-08-2008, 03:32 PM
Based on your description, the 44 lb/hr injectors that come with that kit might be a little too big. That doesn't mean they won't work...just that it will be harder to tune.

Save the changes you've already made to location B or C (so you can go back if you need to) then restore base. Turn closed loop control off and start by taking about 20% out of the global fuel modifier. Now go back into the individual RPM/Load sites and try the fine tuning again.

Scott

West_Racing
07-09-2008, 04:35 AM
Scott:
I will give this a try. It will be a several weeks before I will get a chance to work with it again. I was thinking that I may be able to get somewhere with it only because I was able to get the warm-up and idle to function smoothly. I will post back when I have had a chance to try your recommendation out.

Best Regards; John