I really am not unlike anyone else.I take the suggestions from here very seriously and do more research to have a informed insight of what people are telling me.I lost most of the info I had saved for a EFI for this build when my last XP windows computer went down and the computer repair shop lost the computer.
Recently I have been spending alot of time reading Thirdgen.com on TBI's.Still working on my learning curve there.
As promised I did a search on the Mass Flo Fuel Injection Systems customer reviews.Not to be argumentative in any way,but to add to the info for this thread I am posting the review on it by David Vizard.
Mention Fuel Injection to a carb guy and at the moment he is changing jets he will almost certainly get a metal picture of his counterpart with a lap top programming the system. Well that’s certainly the case in most instances but things are changing. Probably the #1 reason for some one who has been using carbs only for fuel delivery is that they may not be as comfortable using a computer as they are a screwdriver. That, other than cost, tends to be the #1 reason why hard core carb guys don’t convert to fuel injection readily.
I got into a conversation on this topic with dyno operator Doug Aitken. Doug dyno’s a variety of engines – and usually between one and four a day at that. Doug gets a lot of practice setting up fuel injected motors so he has a good window on the situation in terms of what’s user friendly and what is not. We are in the process of building both Ford and Chevy engines for fuel injection purposes so I asked Doug what he thought was the most user friendly system out there. His answer, “Mass-Flo’s system – it virtually programs itself”.
Here is the system we got to make a provisional test on. The test engine was a big cube small block and the combination of cubes and fuel injection made this a very civilised 'monster'.
As things turned out I got a call from Doug a few days later and he asked if I would like to see a Mass-Flo system on the dyno. Sounded good to me so over I went.
I arrived to see Doug just as he was finishing up the install of the engine on the dyno so things were ready in a few minutes to start the test engine. This was a small block Chevy of moderate compression and about 440 inches. This engine was going in a pretty light car – can’t remember what now but it would have weighed only about 2800 lbs. The customer for this engine wanted something with torque everywhere and 550 hp that would run, if needs be, on 89 octane fuel. It had to have a relatively small cam (bearing in mind the displacement, and no expensive head porting).
Self Programming?
Is this system self programming? Not really, it just appears and acts that way to the end user. Essentially when you order a system a fuel program that is reckoned to be close is installed. From here on the system fine tunes itself from the O2 sensor for part throttle usage and meets a pre-determined fuel air ratio when it goes into mass flow mode. As for the ignition curve this is a set program based on the engines spec i.e. cam, compression etc. All that is required here is that the distributor be set to the initial timing called for. If you want to do any fine tuning from here on out it is easily done at a test and tune session the drag strip – or, if you prefer on a chassis dyno. But fine tuning here does mean just that – fine tuning.
The first hint that this was going to be an easy deal was the fact that when Doug hit the starter this engine turned at most 2 revolutions before it fired. It then settled down into warm up mode at about 1000 rpm. After warm up the idle dropped back to about 800 rpm and dyno’s O2 mixture analyzer showed a steady 14.5 or so fuel air ratio. That’s right around where it needs to be for the cats of an engines emission system to work optimally. After that the engine was cycled through various modes to simulate the various throttle openings versus rpm that one would typically see driving around in a normal fashion in a suburban/rural area. After cycling like this for an hour the motor was deemed broken in and an oil change was made plus a check of valve lash and head bolts torque.
At this point runs with more throttle and rpm were done with little or no change in rpm. Because this was all done at relatively high intake manifold vacuum the system was still on the closed loop and was controlled by the O2 sensor readings. Gradually over the next hour the engine was taken to it’s full potential. WOT power runs showed the mixture to be right on 13/1 throughout the rpm band at any time the manifold vacuum was down around about 4 inches or less. Throttle response was just what you would expect of a fuel injected engine – sharp. At this point Doug announced that the system had about programmed itself. We then made some exploratory runs and for our final figures netted 547 lbs-ft and 548 hp. Low speed torque was such that we could not pull this engine below 3500 rpm at which point it was cranking out some 507 lbs-ft of torque. The power curve for this engine after ‘self calibrating’ was as per the graph below.
To take the engine off the dyno Doug uses a carb pad lift plate. This meant taking Mass-Flo system off the intake manifold and that gave me an opportunity to flow the throttle body/mass flow sensor assembly. This showed about 750 cfm on the bench which would normally have been a bit on the small side for a 550 hp engine. The reason for my testing it is that I thought this would be a great system to put on a relatively high effort 383 small block Chevy I was currently building. However my target output was as much as could possibly be had from a cam of no more intake duration than 252 degrees @ 0.050 tappet lift. With the profile chosen that worked out to be 294 at lash. For this I really wanted more flow than this mass flow sensor had so I made a call to Mass-Flo and asked about the possibility of a higher flow sensor. It turns out they have a competition one which goes over 1000 cfm. That decided me right there. My 383 is going to be Mass-Flo injected.
David Vizard
Last edited by admin; 08-26-2009 at 11:26 AM.
