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One for efi guys
Posted: Wed Mar 30, 2011 11:46 am
by JJMclure
I was looking at a manifold that has been modded to run FI and has 42lb injectors fitted. When I did some quick calculations on what size injectors I should run for my engine and estimated power these are more injector than necessary. My (might be stoopid) question is if you had programmable injection and ignition and ran say 96lb injectors but your engine only required 30lb would you have problems? engine is 357 sbc approx 425hp
I was going to buy the manifold but my financial director has stated - your life won't be worth living if you buy anything else for that car before you've payed off what you owe!
Posted: Wed Mar 30, 2011 12:08 pm
by SuperV8
I think 42lb injectors will be fine for that engine.
The problem with using large injectors is at low engine speed they only need to be open for a very short period of time so the ecu may have dificulty fueling accuratly for these events. An ecu with a higher resolution injector control will help. I'm sure some more knowlegable people will comment soon.
42Lb injectors aren't big by any means compared to some. I'm using them in my RV8 which i'm targeting 400bhp.
Tom.
Posted: Wed Mar 30, 2011 4:08 pm
by katanaman
If the injectors have a fast response time and the ECU could control them fast enough you could get away with it. Generally though if injectors are really oversized then the engine will run badly at lower RPM because you cant open and close them fast enough to get the correct fueling. It takes a certain amount of time for them to open properly and close again. Get too close to that and the fueling is all over the shop.
Re: One for efi guys
Posted: Wed Mar 30, 2011 8:17 pm
by stevieturbo
JJMclure wrote:I was looking at a manifold that has been modded to run FI and has 42lb injectors fitted. When I did some quick calculations on what size injectors I should run for my engine and estimated power these are more injector than necessary. My (might be stoopid) question is if you had programmable injection and ignition and ran say 96lb injectors but your engine only required 30lb would you have problems? engine is 357 sbc approx 425hp
I was going to buy the manifold but my financial director has stated - your life won't be worth living if you buy anything else for that car before you've payed off what you owe!
You can of course go too big, depends on injector and method of control.
But 42lb should pose no problems whatsoever.