GPM

If you already have a good carb setup it's probably not worth going to TB.

HaxbySpeed

You can run any ignition you want. Some can only run as a standalone while others can be controlled by the ecm. I probably wouldn't run TBI on a 600hp motor. Two of them work great on a blower though. You can get the Avenger kit 550-831 which is 100% complete for $3099. Or you can get the HP kit 550-830 for $2599. which is complete minus injectors and fuel pump. Both kits come with intakes. If you wanted to run your own intake you can get a retrofit kit with weld in injector bosses. The Avenger system can be programmed with the free software online which makes it the same as the HP system. Don't pay attention to the parts listed on Summitt's site, it is incorrect.

On the Holley system you can set the throttle blades wherever you like and the do a TPS auto set by cycling the throttle twice. The computer will then make it 0-100% without having to worry about adjusting the base reference voltage.

HaxbySpeed

No problem.

articfriends

I was doing that while at Tyler Crocketts dyno under his direction , I'm not exactly sure why we didn't open up the throttle blades more and re-set the tps but I know he was concerned about the tiny, epoxied idle screw and what would happen to the tps if we had to open it too much, Smitty

KAAMA

Haxby, your response/description above is just ONE reason why I would really be interested in the Holley EFI system as smooth idle quality, shifting and drivablility are extremely important to me.

Back around 2001 or so, I was considering using an aftermarket EFI system, but decided against it because I could not see the money light at the end of the tunnel for some guy coming in to custom tune my setup, etc, etc. No EFI systems at the time seemed USER FRIENDLY back then.

Would it be safe to say that aftermarket EFI systems have come a long way since 2001?----at least the Holley???

What reasonable amount of $$$ could someone expect to pay to convert a carbed system to the Holley EFI system being described in this thread???----let's say a pair of carbed roots style supercharged engines?

2-wiring harnesses
2-fuel rails
2-ECM's
4-Dominator sized throttle bodies
16-FI bosses for the intake manifolds
16-Fuel injectors

Am I missing anything???----like high dollar fuel pumps, etc, or anything???

Any imput would be greatly appreciated---thanks in advance

Young Performance

That is a very nice feature. Good thread.


Smitty,
On the MPI intake like yours, you can open the secondaries a little bit without affecting the tps. It has it's own stop screw. I will also drill a hole in each throttle blade and it really helps. I'll start around .125 and work from there if they need to go bigger to help it idle.
Eddie

GPM

They all came a long way since 2001. You would need higher pressure pumps, regulators, filters and a return line for each.

KAAMA

Yeah, thanks....that's kinda what I thought. Actually, I have some layin' around---they're HUGE, rebuildable electric, high pressure, in-line fuel pumps w/integrated filters. I cannot remember the brand name of them at the moment, but they are BAD!

ThisIsLivin

I've installed an Edelbrock EFI on a SBC and the outcome was amazing. I gained a huge jump in performance and fuel economy over the stock motor. The car never ran so good. When I bought my boat the first thing I looked into was going to EFI. My problem is that I have Lightning wet headers and to add an O2 bung would be difficult and new headers with O2 bungs are about $2500 on top of the $3500 for a complete EFI system it was more than I wanted to get into. I have a few questions though, one system I haven't seen mentioned yet is the ACCEL DFI system. I have a buddy over at Kinsler fuel systems and that was the system they recommended to me. They have a marine rated system that is complete and can support over 650hp which is where I'm at. The other issue I saw was that most electric fuel pumps need to be mounted below the tank so they get a good siphon. On a boat that means placing the pump in the bottom of the bilge. Has anyone had a problem with this? Also what is the consensus on batch mode verses sequential. I've done a little investigating in some of the EFI systems and there is a lot to consider with EFI. You have batch mode and variations thereof and sequential mode. My concern is this, how well do some of these controllers handle things such as the wall wetting effect? Under hard acceleration, a portion of the fuel sticks to the walls of the intake port until air velocity increases with rpm. Some systems, specifically Mega-Squirt actually have a complex algorithm that adjusts fuel flow to adapt to this affect. If this is ignored you will be lean initially and then there will be a rich period until your rpm stabilizes. There is also the issue of injector firing timing, When running at full rpm you may be running the injectors at 80% duty cycle which causes some puddling of fuel before the intake opens. How deep can you get with systems like the Holley HP? can you adjust the the integration factor during acceleration? Can you adjust injector timing to suit your cam and engine setup? In a car that accelerates quickly many of these factors are irrelevant, but in a boat that is under extreme load while getting on plane these effects are amplified. Trust me I know, I'm trying to get the bog out of my carb by tweaking the power valve restrictors and tweak the accelerator pumps and jets. Many of us know how to make these adjustments in the analog world. My question is, can we make these adjustments in the digital realm. As I said in the beginning, I have installed an EFI system, but all it allowed me to change was fuel based on load and rpm, ignition timing, and a general enrichment for acceleration. If anyone really wants to know in detail the math behind EFI, I recommend the Mega-Squirt site, I found it to be a tremendous education. It will help you understand the hows and whys so you can get a better tune. As always the discussions on this board are enlightening.

GPM

You may be over thinking things a little, pick the system you want to go with, download the software and check it out. Sometimes less is more. We added 02 bungs in CMIs before, drill a slightly larger hole in the outside than inside, weld everything up.