TBI - Direct port EFI? Switching my BBC over
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TBI - Direct port EFI? Switching my BBC over

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    Senior Member kurtis500's Avatar
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    Default TBI - Direct port EFI? Switching my BBC over

    I am switching out my 750 vac carb on my motor and going with an injection system. Drivability and reliability is the focus. The motor is a 468 rect port BBC at 10.5:1.

    Has anyone here switched out a carb and gone with a Holley Commander or Edelbrock efi system before in a boat? I am trying to decide if the direct port injection is needed or if a TBI system is plenty. Looking for 900cfm+. I know I will need return lines to the tanks so there will need to be dual fuel line valves to switch tanks for return and supply. I am really curious if someone who has done this can tell me the difference before and after. I have done this on my race boats from carbs to injection but those are mechanical and look no way similar to these systems.

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    Senior Member ap67et10's Avatar
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    Quote Originally Posted by kurtis500 View Post
    I am switching out my 750 vac carb on my motor and going with an injection system. Drivability and reliability is the focus. The motor is a 468 rect port BBC at 10.5:1.

    Has anyone here switched out a carb and gone with a Holley Commander or Edelbrock efi system before in a boat? I am trying to decide if the direct port injection is needed or if a TBI system is plenty. Looking for 900cfm+. I know I will need return lines to the tanks so there will need to be dual fuel line valves to switch tanks for return and supply. I am really curious if someone who has done this can tell me the difference before and after. I have done this on my race boats from carbs to injection but those are mechanical and look no way similar to these systems.
    its a night and day difference from a carb to electronic fuel injection. When i first set up EFI on my dads boat I was blown away at the throttle response, ease of running (cold start, hot start, high/low elevation) how consistent it was, no hunting rpm when cruising (especially pulling someone on skis or wake board). biggest difference was fuel mileage. i won't ever go back to a carb.

    Based only on knowing you have 10.5:1 comp. i'd say the engine isn't stock, so don't even bother with TBI setup. it would give you slightly better fuel milage and reliabilty over a carb, but is not worth it on anything with HP or that may be upgraded. they work OK only for stock type deals, where cost is a huge factor. No other reason to run them.

    Personally I'd piece a setup together, but there are many good aftermarket complete kits that are fully tunable and upgradeable. if you want a kit of some sort i'd look to FAST. something like these: http://www.fuelairspark.com/Products...Kits%27-0.aspx

    if you are a do it yourselfer, then i'd look to piece a setup together. Tons of good (often brand new) used parts out there. So many options to choose from. whats the boat? desired use? power output?

    Andrew
    Last edited by ap67et10; 08-16-2010 at 12:28 PM.

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    I noticed in jegs they have some sort of return line fitting with out having to drill and weld on your tank. Might be something to look into.

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    Highaboosta Unchained's Avatar
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    Is this going on the boat in your Avatar pic ?

    Twin Turbo 1800 HP V-Drive lake boat

    http://s621.photobucket.com/albums/t...t=MAH05771.mp4

    Quote Originally Posted by Trigger View Post
    No one cares about your buddies old antiquated garden hose technology.
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    I think I could run more boost but it's a real hand full right now

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    Senior Member kurtis500's Avatar
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    Thanks guys!

    It will be in my 21ft Howard V-drive cruiser family boat. The hydro in the pic has a mechanical Hilborn.

    I am really curious about building a system. How can they be tuned? I am looking for a higher cfm model from 850cfm up. I know the motor needs alot more because I switched out the 850 demon to a 750 holley and it really brought the motor back down much more than I expected.

    I really thought about the new tbi Avenger from Holley which looks easy to add and tune. I'm a little worried about the EFI set-ups since they are much different than the mechanicals which I can do.

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    cfm
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    Quote Originally Posted by kurtis500 View Post
    I am switching out my 750 vac carb on my motor and going with an injection system. Drivability and reliability is the focus.
    Driveability depends on the tuner. IE: looks like it's you.

    Dependability depends on the installer , components used, and how well it's taken care of.


    EFI is great, no doubt. Have you ever thought about getting a properly sized carb ? I've been involved in many carb build ups with even Dominators being able to start right up and idle for miles.

    Ultimately, carb vs FI really depends on what you can tune and repair the best.

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    Senior Member ap67et10's Avatar
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    Quote Originally Posted by kurtis500 View Post
    Thanks guys!

    It will be in my 21ft Howard V-drive cruiser family boat. The hydro in the pic has a mechanical Hilborn.

    I am really curious about building a system. How can they be tuned? I am looking for a higher cfm model from 850cfm up. I know the motor needs alot more because I switched out the 850 demon to a 750 holley and it really brought the motor back down much more than I expected.

    I really thought about the new tbi Avenger from Holley which looks easy to add and tune. I'm a little worried about the EFI set-ups since they are much different than the mechanicals which I can do.
    you don't want a tbi setup, especially not a kit. its just a waste of money. find an MPI manifold and fuel rails. (I actually may have one i might be willing to let go) you will then want to get a 1500-2000 cfm throttle body. find some fuel injectors (injector size depends on engine specs and power) fuel pump, reg, the sensors and you are practically there. at that point you can chose any kind of engine management system you want. lot of guys love the FAST stuff, but Holley dfi works, big stuff, motec, autronic, and a few others. if money is a big concern and your up for some learning and reading, then megasquirt is an option also, im running one, but its definitely not for everyone. You can get your hands on a MS3 now though, so full sequential fuel and spark capable for 8 cylinders. also sd cards for data logging and many more new features...all to be had for about 5-600 bucks.

    biggest thing is that carbs are simple, they are mechanical, they can be tuned somewhat ok and run fine by a 5 yr old. you can practically take a carb out of the box and make it run on anything. if you don't understand HOW an engine works, efi may be a challenge, but by no means too difficult. It takes far more working understanding of whats going on in an engine to tune efi. however there is tons of info out there, and at least a few people here that can help.

    I recommend anyone wanting to do efi, to do it on their own. read, take your time, understand what and why you are doing something before you do it. if you don't understand, don't do it. Fact is though, that if we put o2 sensors on every carbed boat out there, i guarantee you'd find that even some of the worst efi tunes are better than most carbs out there. the inefficiency and waste would probably blow peoples minds......eh or maybe it wouldn't. Biggest problem with efi is most people that had problems never understood what and why they were changing and modifying what they were. efi is a flood of info from an engine, it needs to be understood and calculated correctly.

    Andrew

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    Senior Member ap67et10's Avatar
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    Quote Originally Posted by cfm View Post
    Driveability depends on the tuner. IE: looks like it's you. no different than a carb

    Dependability depends on the installer , components used, and how well it's taken care of. still no different than a carb


    EFI is great, no doubt. Have you ever thought about getting a properly sized carb ? I've been involved in many carb build ups with even Dominators being able to start right up and idle for miles. if you can't make a carb start and idle than you shouldn't touch anything.

    Ultimately, carb vs FI really depends on what you can tune and repair the best. yes, so if you have no desire to challenge your own intellect and working knowledge of an engine; do something new, and somewhat different than everyone else, or be able to look at what you accomplished and know most people wouldn't even try it. then you need to stay with a carb like everyone else.

    AP

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    Senior Member kurtis500's Avatar
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    I am up for the challenge for sure. I build my own motors and etc. and I do understand the engine enough to be able to manage the EFI if I take the time to understand it. I'm pretty savvy on the laptop as well so I think I can handle this from the standpoint of an experienced beginner.

    What I don't have experience with is the ability to piece together an effective system without buying off the shelf stuff. I was looking at the Edelbrock pro-efi system for the BBC. The distributor combo and all-in-one package is tempting for someone like me who is new to this. I certainly have the ability to piece together the system but i dont want to be a pest by constantly asking questions and etc. then end up with a system just as expensive doing the same thing. I would like to know a lot more about a piece together system, maybe some pics and etc if anyone knows where they can be seen..

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    Senior Member ap67et10's Avatar
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    Quote Originally Posted by kurtis500 View Post
    I am up for the challenge for sure. I build my own motors and etc. and I do understand the engine enough to be able to manage the EFI if I take the time to understand it. I'm pretty savvy on the laptop as well so I think I can handle this from the standpoint of an experienced beginner.

    What I don't have experience with is the ability to piece together an effective system without buying off the shelf stuff. I was looking at the Edelbrock pro-efi system for the BBC. The distributor combo and all-in-one package is tempting for someone like me who is new to this. I certainly have the ability to piece together the system but i dont want to be a pest by constantly asking questions and etc. then end up with a system just as expensive doing the same thing. I would like to know a lot more about a piece together system, maybe some pics and etc if anyone knows where they can be seen..

    I put my system together from pieces and parts, if you have questions i will answer anything you want to know (that i can). I love to see more people interested in doing efi stuff on their own. first, what are the specs of the engine? ci? estimated power? what kind of use? gas or e85? any plans to boost it later or up the output? also do you have a budget in mind already?

    Andrew

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    21 Daytona Outlaw's Avatar
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    Quote Originally Posted by kurtis500 View Post
    I am up for the challenge for sure. I build my own motors and etc. and I do understand the engine enough to be able to manage the EFI if I take the time to understand it. I'm pretty savvy on the laptop as well so I think I can handle this from the standpoint of an experienced beginner.

    What I don't have experience with is the ability to piece together an effective system without buying off the shelf stuff. I was looking at the Edelbrock pro-efi system for the BBC. The distributor combo and all-in-one package is tempting for someone like me who is new to this. I certainly have the ability to piece together the system but i dont want to be a pest by constantly asking questions and etc. then end up with a system just as expensive doing the same thing. I would like to know a lot more about a piece together system, maybe some pics and etc if anyone knows where they can be seen..
    You can do it... getting ready to fire mine up very soon. I pieced together
    a system and have learned a bunch. Pretty simple once you get into it.
    #55

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    Super Moderator HammerDown's Avatar
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    Quote Originally Posted by ap67et10 View Post
    I put my system together from pieces and parts, if you have questions i will answer anything you want to know (that i can). I love to see more people interested in doing efi stuff on their own. ...
    Andrew
    You have one here, but I run wet OT headers and don't know of a 02 sensor that will work wet
    <img src=http://www.performanceboats.com/gallery/data/500/medium/06-30-11_1234.jpg border=0 alt= />

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    Senior Member ap67et10's Avatar
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    Quote Originally Posted by HammerDown View Post
    You have one here, but I run wet OT headers and don't know of a 02 sensor that will work wet

    this definitely makes it much harder to run a really effective efi setup. however if you get your VE tables setup well its very possible to not run an o2 sensor. I would recommend welding in a bung for either a second set of ot headers or your current set and tuning dry. then switching back after you have a good tune in it. o2 is a tuning device, many people do not use o2 as a compensation device, meaning that often times the o2 reading is given 0% authority to compensate for fuel trim. if o2 reads 16:1 and 0% authority for o2 reading, then nothing will happen...it will not add more fuel. o2 should PRIMARILY be used for tuning your VE tables. once set, it can be removed and back to wet OT headers.

    also typically in a 75% and higher throttle angle, o2 is completely ignored. so WOT won't be using o2, even on a system that used o2 for authority.
    Last edited by ap67et10; 08-17-2010 at 01:50 PM.

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    Super Moderator HammerDown's Avatar
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    Quote Originally Posted by ap67et10 View Post
    this definitely makes it much harder to run a really effective efi setup. however if you get your VE tables setup well its very possible to not run an o2 sensor. I would recommend welding in a bung for either a second set of ot headers or your current set and tuning dry. then switching back after you have a good tune in it. o2 is a tuning device, many people do not use o2 as a compensation device, meaning that often times the o2 reading is given 0% authority to compensate for fuel trim. if o2 reads 16:1 and 0% authority for o2 reading, then nothing will happen...it will not add more fuel. o2 should PRIMARILY be used for tuning your VE tables. once set, it can be removed and back to wet OT headers.

    also typically in a 75% and higher throttle angle, o2 is completely ignored. so WOT won't be using o2, even on a system that used o2 for authority.
    Hmmmm, interesting and thanks for the reply.
    I was under the impression that like in a automobile EFI was always adjusting for what's best at each second of operation (if needed)

    So no real worries from running at a cool/dry 55 degrees ambient temp vs hot/humid 100 degrees?
    BTW I'm at sea level.
    <img src=http://www.performanceboats.com/gallery/data/500/medium/06-30-11_1234.jpg border=0 alt= />

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