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I thought there was an EFI sticky somewhere but I have not found it, so moderater, move if you wish.

I have been kicking around the idea of adding the http://www.summitracing.com/parts/msd-2900 throttle body type fuel injection from msd.
I am familiar with this type as it look almost identical to the Eddy ProFlow multiport injector kit but Msd is throttle body. I had this unit on a ZZ 3 motor in my TriFive. 700r ,370 gears. Got about 22 mpg. This car sold and I only have my orginal 69Z

I am trying justify the difference between my 3310 holley on this 383 motor and TKO that gives me 23 mpg and a change to the MSD 2900 unit.

I know the story , if it aint broke stuff. But I wonder if anyone out there has made the switch and compared numbers.
if no comments , I may just flip a coin. Really not having any issues with my carb set up at all. Maybe just looking for a change in life. Worked on Holley since I was 16 so if its out of tune, I can tell it.
With the old Proflow, it took some understanding , especially when I went for 3300 elevation to 10K at Clines Corner , NM.

So I am looking for comments, good or bad let it rip.
 

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TBI doesn't like high elevation. Chevrolet owners manual said so, to the effect if you bought one and moved to a high elevation mountain state that you had to take it into a dealership there for a new computer chip at your expense. It has to do with MAP vs MAF: air flow vs manifold vacuum.

Carburetor has been around for over 140 years. It works and will yield higher horsepower from any engine than EFI ever will. It will not give as good a mileage number nor protect your motor from bad gas the way EFI will.

In addition to the sensors you need to ask about the software. How flexible is it, is it easy to modify, etc. Your complaint won't be with the hardware but the software that controls it and now your car.

I think carbs are great. But this is only because; aside from new cars and pick-ups I own I have never even looked under the hood of any of my vehicles that have EFI. It's all magic and I'm no magician.

Larger Dave
 

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A friend of mine just put the MSD EFI on his 69 Charger with a slightly built 383. He's a novice and installed and set it up easily by himself.

He loves it.

Look for sales coming up on Jegs and other online vendors. He go his on a 15% off deal and free ship.
 

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Carburetor has been around for over 140 years. It works and will yield higher horsepower from any engine than EFI ever will. It will not give as good a mileage number nor protect your motor from bad gas the way EFI will.


Larger Dave

Curious why you say the horsepower will be higher on a carb than EFI. I thought these throttle body EFI's were picking up 20-30hp when dyno before and after the conversion?
 

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Research any EFI vs. Carb dyno comparison and carb wins every time. Issue with carbs is you either tune it for WOT or to cruise. Unlike EFI it doesn't do both well because of how it works (differential in manifold pressure in relation to pressure above the venturi). EFI has the limitation of band width and not exceeding 100% duty cycle on the injectors for any extended period of time (once again it is a matter of having WOT or mid range and streetable cruise RPM set up).

EFI isn't magic. It offers only one advantage over a carb and that is the speed at which monitors the motor's functioning. It can pull out or add timing and offers fuel to air correctly regardless of weather conditions (still can not compensate for humidity) where a carb tuned for the ragged edged of detonation (to maximize horsepower) may run well on track day, but when the weather changes, you are on the wrong side of the knife's edge and you can loose a motor.

A throttle body is basically an electronic carb as far as fuel distribution is concerned. EFI on a six will beat a carb hands down across the board compared to a carb stuck in the middle of a log manifold. The TBI and carb will share the same fuel distribution problems that port injection can cure (especially with an aftermarket fully programmable controller that can be tuned for good ports and bad ports as encountered with a BBC). The Edelbrock and Holley TBI EFI kits are self learning, but are not fully user programmable. The brain is optimized for street driving in that it averages performance, not allowing you to program the tables in respect to your desires in response to what you have observed on a dyno or the track.

There is one other advantage to EFI (even a TBI) is that it will accommodate a centripetal blower or a turbo charger much better than a carb can; if either is in your future.

Big Dave
 

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Discussion Starter #6
All good comments, after learning more about the MSD set up, less I am liking it. I am leaning back on my carb at this point.

When I first installed Eddy Proflow , I thought it was a good deal. Issue I had with it and even contacted an engineer on it, was the inlet air temp sensor, which was mounted on the carb.
The engine required like most EFI, the chip to match the intake cam degrees.
All ran well until hot weather set in, then engine would surge at in any traffic when the inlet air sensor temp got over 140°. I was sitting in traffic on a 114° day, down town. My cooling system ran about 100° higher than ambient so water temp was about that, the hand held tuner recorded this as well as inlet air temp.

The electronics could not find a air or fuel window to compensate.
After discussing with the engineer, he agreed this was a problem, he recommended I move this sensor away from the engine but in path of fresh ambient air, which I did. The car was a 57 Chevy and above the head lamps , there was a fresh air duct that used to feed the interior floor. I put the sensor in that air passage and never had any other issues.

I see this MSD has almost the same sensor , but in the throttle body. With some tweaking , I could put the sensor in the cowl hood inlet and solve this.
So, I am still debating. I rebuilt my Z with cruise street so it appears I will keep the carb, at this point. I am getting good mileage at 23mpg running 2300 rpm . So I am asking myself, why mess with it. If I got 30 mpg, maybe but I don't see it unless I went to a v6 .
Thanks to every one that commented.
 

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Thanks for the response Dave. I have been researching the TBI EFI as well and am leaning toward the FAST EZ-EFI 2.0. Basically the same as the MSD but more positive feedback and the mechanic I have been talking with has had no issues with them vs issues with the MSD he has installed for customers.
 

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EFI on a six will beat a carb hands down across the board compared to a carb stuck in the middle of a log manifold. The TBI and carb will share the same fuel distribution problems that port injection can cure (especially with an aftermarket fully programmable controller that can be tuned for good ports and bad ports as encountered with a BBC). The Edelbrock and Holley TBI EFI kits are self learning, but are not fully user programmable. The brain is optimized for street driving in that it averages performance, not allowing you to program the tables in respect to your desires in response to what you have observed on a dyno or the track.
Actually you cannot do any other kind of fuel injection on the L6 motors other than TBI. I had a long talk with Langdon about it. GM worked on the problem for 10 years before giving up. The siamese port design is the problem. You get pooling in the head using port injection. Try it and you'll blow the engine.

Only applies to the L6 (235, 250, 292) engines due to head design. Unfortunately there aren't any heads available for the engine unless you make it up yourself.
 

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Don, the correct thing to do would be to try it yourself to see and then if you don't like it offer it to me for 75% off.
 

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Discussion Starter #11
Don, the correct thing to do would be to try it yourself to see and then if you don't like it offer it to me for 75% off.
That's friends for ya. What would we do with out them. Lemme see, 75% off $3200, , you could buy any carb you want for $800. If I try it , and don't like it, I got guys in south texas that will take it off my hand for a better deal. Nice try.

Yes Brian, there is or was an EFI sticky that JimM started years ago I believe, he was running the commander unit. I thought he still had it but after he switched, he got a about same mileage as I do now, so I think for mileage, I don't think I can get much better than 23 anyhow to justify.

Thanks again guys.
 

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Try it and you'll blow the engine
Evidently the spark is a problem also. Kid's 01 Bonneville was in the body shop and battery went low with dome, hood, what ever lights on. They tried to start it and BOOM the plastic intake exploded.
 

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Evidently the spark is a problem also. Kid's 01 Bonneville was in the body shop and battery went low with dome, hood, what ever lights on. They tried to start it and BOOM the plastic intake exploded.
Sure that was not a leaking nitrous valve?
 

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The EZ-EFI 2.0 looks pretty easy to install, Hot Rod has a YouTube video of the basics of install.
The video makes me even more tempted, on my car I could get The basic kit, since I already have a fuel system designed for over 1000HP, all I would need to do is swap a few parts, run a few wires, and re do the throttle springs.
 

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Don - I have about the same feelings as you regarding EFI. Sure would be a fun project - but it's hard for me to justify the cost for easy cold starts and a few MPG. Since I'm now oficially married to this 383 an LS motor is out of the question, so it's tempting to inject the SBC. I have decided that if I do, I'll spend the extra dough and get something with port injection an timing control, such as the FAST XFI or similar. But nahhhhh, the $150 Holley and $17 fuel pump have been working well for a long time. Why did you have to bring this up anyway? :)
 

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Don - I have about the same feelings as you regarding EFI. Sure would be a fun project - but it's hard for me to justify the cost for easy cold starts and a few MPG. Since I'm now oficially married to this 383 an LS motor is out of the question, so it's tempting to inject the SBC. I have decided that if I do, I'll spend the extra dough and get something with port injection an timing control, such as the FAST XFI or similar. But nahhhhh, the $150 Holley and $17 fuel pump have been working well for a long time. Why did you have to bring this up anyway? :)
Just a random thought, I had some guys down south doing what I did with the 57, installed an Eddy Proflow 3500. but they ventured off with a FAST setup and injectors. They had issues but the tech guys worked them out.
Then another friend went with the MSD2900 and tells me they did not put a return line in. After looking at the kit ,I can see how the fuel dead heads if you don't run the return line to the tank , which I favor.

I got to looking at the $$ involved and compared what I have with total cost of $3500. I just could not justify the fuel difference and I don't think THIS efi would outperform my carb set up and mileage and streetability , I didn't see the project worth the $$, so the topic is closed for now.
Just a thought, but the LS bug is bugging me, I see so many conversions to the LS which I know will out perform my motor, but then I hate to part with retro.
Still thinking here too.
 

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Discussion Starter #18
Did the conversion to EZ EFI and once I worked out some unrelated bugs I love it.
Which brand did you use? Did you put a pump in tank? Return lines?
 

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I did the EZ EFI system 3 years ago with an external fuel pump and used my existing fuel line as the return and bought a Moroso adaptor piece that spliced into at the fuel fill and returned the fuel through that. They had the non return version just out but I thought it would be easier on the pump to return it to the tank.
 
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