Need Fuel Injection recommendations for boosted 1200-1300 HP SBC

[Eric68]

I know Scott would never believe that I am asking this LOL but I think there is a time where fuel injection is absolutely the way to go. I think this is one of them. Here is the combo -- it is important to note that this engine will be run on E85 ethanol, not race gas!

377" SBC -- 4" bore x 3.75" stroke
AFR 210 Eliminator heads
Edelbrock Victor Jr manifold
Comp custom solid roller: 248-260* @ .050 on a 113* LSA, .630" lift
9.2:1 static compression ratio
ProCharger F1R, non-intercooled, but has fogger nozzle in outlet of blower spraying E85 for cooling at WOT.
24 psi of boost at 6,000 -- expect closer to 28 PSI at 7,000

This combo put down 848 RWHP at 6,000 RPM (should make a ton more at 7k) with a carb before torching a piston. We had a lot of timing pulled out with a MSD 6btm but the carb went lean on us. I don't think we can get enough fuel through the needle and seat to keep it fat at high RPM.

Sooooo . . . . .

I am thinking Big Stuff 3 with 16 injectors. The thing though is that I am not an EFI guru and am estimating 160 lb/hr worth of injectors is needed. Probably a set of 96# and a set of 65# ????

Any thoughts on this? I am open to any suggestions on injectors, controllers, etc since we are starting pretty much from scratch here.

[dieselgeek]

Re: Need Fuel Injection recommendations for boosted 1200-1300 HP SBC

street/strip application only? I think a BigStuff3 will work for you.

Less important than the controller, is the environment you're putting it in. The ignition to spark that kind of mixture is either going to be MSD-7 kind of setup with a distributor (which makes a LOT of electrical noise - I am helping a BigStuff3'd BBC guy from Bonneville sort out the electrical noise that's causing all kinds of goofiness with his EMS)... I'd be very careful to separate the "noisy stuff" from the "sensitive stuff" - avoiding power coupled noise ala Bosch Automotive Handbook... that's usually the biggest issue in big power combos like this one.


I think you're fine with 160lb injectors if they'll support your peak power needs on e85. It'll be pretty close though, won't it?

BS3 is a decent first system to learn on. Lots of people can help you out, including me. I think it's the system I'd use if I had to choose from the popular Meaney/Domestic systems. If money weren't a problem, I'd go with MoTec. If money WERE a big concern, I'd go straight with a megasquirt set up to drive either 8 or 16 injectors. The megasquirt and MoTec give you the benefit of being able to tune for injector opening time and hold voltages, which *really* helps idle and drive-ability on the big 160s - BigStuff doesn't give you that, so the staged injectors might be a good idea on that. However, BS3's staged injectors are an "on/off" design... which kinda sucks anywhere but WOT use on the dragstrip IMO. On a megasquirt or MoTec, you can set up dual VE tables for EACH bank of injectors, allowing better control when the second set comes on.

Something else I'd lean towards is a high res crank trigger and individual coilpacks. The BS3 usually is paired with LS1 coilpacks, which would be *OK* on this combo, but might be marginal... if you go through the extra effort of running a cam position sensor (can get an MSD cam position sensor that plugs the dist hole) then you can run sequential coilpacks - these really allow bigger plug gaps, less concern about loading up the plugs during warmup/idle, etc. Knowing you, you should have a blast making this thing more driveable than granny's new Pontiac! Best thing about coilpacks is they realyl eliminate the noise that causes issues with the EMS. You really have to step up your electrical skills to make sure electrical noise isn't causing you issues. Jay Brown's been through this lately... he might have some good input.

If you want a middle of the road option, there's the EMS-pro which has a warranty, tech support (me!). It's about $900 with a bare wire harness. One downer to any of the MS variants is, you have to make your own harness for the car. Upside to the MS variants (including EMS-pro) is that they'll work with higher resolution crank triggers, control more options for coilpacks, have WAAAAY more people on the internet who are literate at them, etc. Gone are the days you have to build your own, too.

I'm sure I am missing some things, so feel free to follow up with more questions. This'll be a lot of fun for you, I'm sure!

[Eric68]

Re: Need Fuel Injection recommendations for boosted 1200-1300 HP SBC

Thanks a lot for the good info Scott. You bring up some good points to consider (which is why I went straight to you to begin with!)

This car is a street strip setup and will get driven / cruised a bit. The owner is not at all an electronics or software guru -- all that stuff seems to fall back on me. LOL Fortunately, my first occupation was very electronics based and while I'm not up-to-date on what's happening these days I can still build a mean wiring harness.

The drivability piece with the real big single injector concerns me a bit and honestly I don't quite understand the details on injector operation, like hold voltage, but the ignition stuff and noise control sounds all reasonable and doable.

[dieselgeek]

Re: Need Fuel Injection recommendations for boosted 1200-1300 HP SBC

Thanks a lot for the good info Scott. You bring up some good points to consider (which is why I went straight to you to begin with!)

This car is a street strip setup and will get driven / cruised a bit. The owner is not at all an electronics or software guru -- all that stuff seems to fall back on me. LOL Fortunately, my first occupation was very electronics based and while I'm not up-to-date on what's happening these days I can still build a mean wiring harness.

The drivability piece with the real big single injector concerns me a bit and honestly I don't quite understand the details on injector operation, like hold voltage, but the ignition stuff and noise control sounds all reasonable and doable.

My advice would be to start with 160 lb injectors, even if you go the BS3/FAST/DFI route. It's less of a challenge to make that work well, than it is to add hassle of of 16 injectors. The "drivability" concerns don't really increase linearly with injector size... once you get past 50 pounders, they all may or may not present some challenges.

I was able to get Huber's mustang idling on 160 lb/hr injectors without any trouble, and it drove like a stocker, on his BS3 (before we switched him to an EMS so we could get rid of the distributor), and that was on gasoline. The more I think about it, on e85 you will still have something like a 4ms pulse width at idle, which is more than enough range to tune a good idle... If you're leaning towards BS3 for comfort reasons, I think you'll be fine. Just beware the noise concerns, nobody's instructions include anything about what it can do to an EFI system - but anyone whose been through the whole "tach signal" hassle will tell you - it's worth planning for it up front. When it's time, just post up your questions and me and horsewidower will knock 'em out. :D

Can't wait to see the videos either. I wonder if you'll become a convert??

[horsewidower]

Re: Need Fuel Injection recommendations for boosted 1200-1300 HP SBC

I have lots of experience on how not to do it!! ;)