I have a 68 restro mod with a massaged 350 with procomp headers, Edlebrock cam (low vac at idle) and lots of other stuff. I have been thinking about going EFI for some time. I know there are other threads about various systems but I am more interested in a sytem with a MAF to feed the computer and a system that will also control timing. I have read about various dis systems (non EFI) to control timing but think a complete system is the way to go rather than piece-meal it together. Now I will say I tried a speed density system for over a year and just could not get it to work right. Went back to the carb for the time being. My engine runs very strong with a carb and I just could not get the power from the speed density system or keep it from pulling fuel under various loads. My cam has a lot of overlap so the engine was a bear to try and tune anyway. (At least for me). I did learn a lot about fuel tables, A/F, timing, and so on. I could either have a great idle or great acelleration but not both with that system. I logged several hours of running and burned a heck of a lot of fuel , spent time on the forum and got lots of advice from others using the speed density system but nothing ever seemed to work right. So now I am looking at what I believe is refered to as a air density system. So, who out there has used a Mass Flo system and what are your thoughts about it? I don't want to start a debate on which system is better or a bashing contest, but rather what did you experience with the system?, what kind of engine was or is it on, a stock, moded, or super stock? Feedback from users is of more value to me than a salesman who don't use a system on their car. Thanks for any help or thoughts on this particular system.

 

Why do you think MAF will be better than MAP with a big cam? Most people give up on trying to get MAFs to work at low RPM with monster cams.

Did you go through the effort of wideband tuning your VE table?

 

My cam is not really a monster but does have overlap that causes the wide band 02 to false read. (At least that is what I was told by experts on the forum for the EFI). I am not a tuner but I do know Carbs and how to set them up. Like I said the speed density or load density may be fine for some but not for me, at least not the system I used. Nothing but constant tuning. Yes I did all the VE stuff, looked at MAP at various RPMS, several hours of logs, posted fuel tables etc etc. I have, just like several million people, a MAF system on all my other vehicles, all OEM. NO issues or concerns. I have done several mods to my C5 and then had to make only minor changes to the fuel map using a well known tuning software. So after doing a lot of reading I thought I would inquire about the aftermarket EFI MAF system and see what results folks are having. The other system I used is a mood point now as it has been removed and gotten rid of. Please, I am not debating a particular system. Belive me I know that absolutely nothing is bolt on and go or plug and play. I only know what I experienced with one speed density system and just want to know how the MAF is working out for anyone who is using it. Lots of LS swaps in C3's going on and I see that folks are retaining the MAF system, just a thought.

 

Im on the road today and will be home tonight. I have run the Mass Flo system wit ha big solid flat tapped cam and then went to a roller with less over lap. I will comment more when I get home and can type something up. I am doing an LS3 swap right now and did change the cam and am running the stock computer setup with a tune. Not done yet.

 

condor7,
I'll chime in here to keep the thread at the top until Gordonm sees this and responds. I have both his old Gen1 motor and his Mass Flo fuel injection system that he sold me last fall before he went LS. I'm just a week or so out from my first test drive after a TON of work battling a disease called, "whilyeratititis". What I can tell you is that he had the same issues with funny idle that he solved by having a custom ground cam made by Comp Cams. I don't have the specs handy, but it's a pretty healthy cam. I can tell you that the Mass Flo is a top quality kit with a very nice wiring harness and very accurate and descriptive instructions. I also believe that Mass Flo additionally offered to re-program the ECU to alleviate the driveability issues, but Gordon went with the custom cam. He can elaborate more when he responds. I've fired up the motor a couple of times to test that all sensors are functioning and that the ECU is happy. Fired right up with no issues once I finally got things sorted. I don't think you will be disappointed with the Mass Flo kit at all. Gordonm heavily documented his build of this engine and the installation of the Mass Flo kit here on the forum. Just search his user name with threads initiated by him. Go back a bit and you will see a ton of info that can answer your questions.
Good luck!

 

Ha, G still beat me to it!

 

Thanks for the information. I looked at GORDONM's thread on the LS install and would like to go the LS direction. In the meantime I may be just as happy with the EFI system provided I can get it to function right. Knowing the vendor will assist in a tune for my application is a plus. I don't want to swap in a different cam. I think EFI is the way to go just don't want it to fight me. We love driving the 68 but wife won,t get in it if it won't run right. I have installed a TKO 5 speed and a 3.08 rear from a 70 big block, A/C, lots of suspension stuff and so on. I can cruise at 70 MPH at about 1950 RPM and stay right with the C5,6's. Really a fun car to drive. Don't know about MPG because Itried the EFI after the rear end swap. Never got it to work right. I did get 19 MPG at 75 MPH with the 3.70 rear and a Holley Carb. Would like a functional EFI that will compliment my car, thus the questions on Mass Flo. Mr GORDONM, I might be asking several questions as long as you don't mind.

 

As delivered from the factory, LS systems use a hybrid mode for determing fueling below a certain point. At higher RPM, it's MAF only. This is due to MAF's difficulty in getting a correct signal at lower airflow demands. (Bear in mind that the amount of airflow changes significantly at low load as you change the throttle but less so as you accelerate through a gear).

By "most people" I meant "most people", that is, tuners and other experienced engine builders. Getting a MAP system configured correctly requires a little more initial time investment than MAF, but once it's dialed in it should last until you make a significant change to your engine.

MAF systems should require the same amount of tuning, the idea there is that once you've dialed in the MAF it shouldn't require any changes. "Tuning" a MAF is basically calibrating the transfer function. Tuning VE requires new effort after a change because it's based on volumetric efficiency estimates. If those are off, your car won't run right.

The reason I bring it up, is if you're having problems getting your car to run in MAP mode, the odds are high (potentially higher) that you'll have problems getting it to run with a MAF setup.

Of course, if the particular system you were using just didn't cut mustard, that's a different story.

The LS series of computers offer great control, by the way, and I don't see why one would want to replace them with something aftermarket for the large majority of engines out there. I've spent some time calibrating them and once you figure out what all the tables mean and how they related, they work great.

That's what I'd recommend if you're going with an LS build. I'm friends with a local tuner who runs 1000+rwhp cars on OEM ECMs. From there, you can choose to go MAP, MAF, or MAP+MAF. (I tune my ECMS in MAP only, then MAF only, then let them run in MAP+MAF)

 

Shark Racer, Thanks for the input. I think EFI is the way to go. I had a bad experience with a speed density system so that is why I am asking about the MAF system. My bad experience was constant tuning with the laptop. Never did get it where I felt that I had power and was using less fuel. I have done all sorts of things to my Vette to fix electrical issues, exhaust leaks and so on that I know affected the system. I made shielded ignition cables because of EMI issues, re-routed stuff and everything. The system still would not perform consistantly. Did not have a cold start issue, did not have a wot issue, I did have some idle issues and also had cruise issues. Idle issues continued between the IAC and the 02. Seems the ecu just did not know what to do, some days okay and on others way to rich or lean or doing a lot of switching between the two. I replaced the 02, CTS, wires and so on. Put up with this for over a year. After putting a carb back on, was on the road in no time getting power enough to bark the tires in third gear and then go to a very smooth cruise. Vacuum holding very steady at about 12 inches at idle and I can even idle at 875 without concern. I just could not get the speed density system to do that. I admit some of that was my inability to properly tune the system but once I had others involved and other calibration tables to try i still had issues. I am a great deal more learned at the aspects of tuning now so understand a great deal more. Not saying I can be a tuner but I understand how the stuff is supposed to work and how to adjust things much better. Perhaps the system I used had a internal problem that never did reveal itself I really don't know. I look forward to input about the MASS Flo system. I am not 100% sold on it one way or the other. It might be to my better interest to start looking at putting in an LS3 or something. I have been reading a lot on this install and it really sounds appealing. It would be a major undertaking but isn't everything? But first things first, the MASS Flo system might be just what I want and be happy with. My mouse motor is no slug but it is not NASCAR either. I don't race the car just want a good driver to take on trips and stay with the C6's C5's without stopping for fuel every stop. There is a lot I have done to the car to achieve this goal, just think EFI would make things a whole lot better.

 

Thanks for the info. I just want you to be cautious is all. A lot of the issues you mentioned will affect a MAF car just as much as they will a MAP.

Would have been interesting to see what was going on with a datalogger. Make sure MASSFlo has good datalogging functionality or you'll be in the same boat.

A big issue can be injector constants - if they're messed up you can chase the MAF transfer function or the MAP VE tables all day long and never get it to run right.

I definitely prefer EFI to carb, but I'm going to mess with the Q-Jet on my 78 so that I can say that I did!

 

Hey Mr. Gordonm, I look forward to your real life experience with the Mass Flo system. I did find some other threads with some postings but nothing really in any kind of detail. Also if I read the Mass Flo stuff correctly it also controls timing? Is that the purpose of the new distributor? I also think DIS is the future as well but want to hold off until I see what all this system has to offer. Thanks.

 

It's been several YEARS in the waiting, but we just fired up my new motor today with a MassFlo system on it. Haven't run it for long or test drove it yet, but it fired right up, sounds great, and so far, has idled fine.
The motor is a 454 small block (400 block) dynoed (using the MassFlo) at 572 h.p. and 585 ft./lbs. with a custom grind Comp Cams roller.
The MassFlo system is well built and laid out and controls lots of functions. Very plug & play. In the next week or so, the car will be out on the road being driven and I can give a better assessment then. So far so good though.......

 

You can get a lot of good EFI info on pro-touring.com and lateral-g.net. The guys on those forums are just as helpful as the guys here and they are extremely interested in modded vintage Corvettes.

 

Hey UXOJERRY, thanks for the tips on the web sites for info. I will certainly check them out. And Tony Rags, looking forward to your real world experience witht the system. Right now I am getting lots of power from the Quick Fuel Tech carb (750 CFM Street Slayer) that I installed. Not a real hot rod carb but it does get the job done. Like the all-aluminum fuel bowls and stuff that is set up to handle the alcohol in our fuel. Still very interested in the Mass Flo system. I see where guys are converting to TPI systems with some degree of success. I don't want to go that route. Nothing to do with looks as this is a restromod anyway. Thanks for all the input so far. (Have some other things to get done with the car but it is driving very nice now.)

 

I drove the Mass Flo system for 2 years and was very pleased with it. It had the same power top end as a well tuned carb I had on it but was way more driveable in the mid range rpm. It fired up every time right off the bat no fuss at all. I had a pretty big solid flat tappet cam with it also. I then changed it to a roller cam with a little less duration but a lot more lift. Also put on bigger cylinder heads. This really woke it up and the Mass Flo system adjusted with no problem at all. I really liked the system a lot. Ijust got the itch to do an LS motor so Isold the whole motor and fuel injection to a forum member. He is about ready to fire it up shortly.

Yes you set the timing for if I remember correctly about 12 degrees with it unplugged. Once this is set you plug it back in and the computer takes care of all timing.

 

Does anyone know how to attach or insert a .mov file into a post on here? I have a video clip of the motor being started with the MassFlo I can show off.

 

Upload it to Youtube and wrap the letters/numbers at the end of the address with the tags in the toolbar when using the "advanced" reply to thread.

Example - http://www.youtube.com/watch?v= RXHzMHmYrQs (Not my vid, just a random engine start)

You'll see the "http://www.youtube.com/watch?v=", you want to wrap just the sequence after the "v=". So it will look like this (without the spaces) [ YT ] RXHzMHmYrQs [ /YT ]

 

I have had a speed density system on my '72 since '95, using stock computer....1227730 I too had a long many years with rough idle that set in on the car about '99 or so, and I finally found the roller CAM was a POS ZZ9 cam from TPIS, I had never heard of a roller cam wearing like this one did, it was plainly lousy manufacturing....that damn simple.....

put in a stock L98 cam, and engine is fine now, nice calm idle runs fine....



I"m in Orange Park, pm if you want to get together some time, I"m retarred so anytime is fine....

 

I put a mass-flo system in my 61 bel air with a massaged & fortified 409 w/large port iron heads. The install was straight forward but when I went to fire it up it did not run well anywhere in the rev band. Trouble shooting pointed to the ECM which is from OEM fox mustang and is pre-programmed w/learn as you go function. Chris sent a new ECM and it seemed to solve the problem. Spring '11 back on the road and it was running rich at idle and lean at WOT--lots of knock. Put it on the dyno and the fuel maps were a mess but the ECM is not programmable and I gave up on this and bought a "new" fox ECM on line for $100 and installed a programmable Moates chip and had it tuned on a mustang dyno and it now runs great. Sat all winter and fired up on the 1st turn of the key. I qualify that I bought the system 3+ years ago and there a lot more options for EFI now. If I were buying a system today it would be with a programmable FAST type brain.