Jim "sez" EFI - what's you'all think?

[elagache]

Dear V-8 Buick Faithful,

First, for those of you who have been following the soap opera that my venerable 65 Buick Special wagon has been going through: here is a update.
After almost 8 months in body shop purgatory, the car might actually get released in a week or two! This poor car has spent more time in "prison" than lots of criminals! :puzzled:
CK-Performance "hopes" that the 200-4R transmission might go out sometime next week (okay, so assume at least 2 but still progress. :cool:)
Alas, Jim Weise is almost certainly going to lose his bet that could complete the new engine for this car before it gets out of the body shop (I should have bet him the cost of the engine! :laugh:)Which brings us to the current installment of the soap opera for which you'all are invited to comment on. Last week, Jim sent me an email with the rather distressing problem there-in:



I noticed in the last set of TA heads (Note: these are stage-2 street heads) I did they have eliminated the water passage to the crossover (used that instead of exhaust heat) which is really going to put a bind on good choke operation.. Cold and mid temp operation has always been an issue, as using the water instead of the exhaust head has never been as responsive and quick in heating up the choke coil. And the aftermarket choke coils are another issue, they never worked as well as the factory choke coils setup.

Recently I had the opportunity to work with a guys GS with the EZ-EFI system from FAST on it, and I was impressed. Excellent drivability under all temp conditions, and he reported that he saw a noticeable increase in economy after the swap. Of course, I have no idea how his carb tuning was, so I can't really speak to the validity of the economy statement, but I can assure you that there is going to be no real good way to have a functional choke on the good working 4MV Q-jet we had planned to use.
Now considering how fancy this engine is going to be, having it hard to start is a really bummer. Worse, this car has always had choke "issuez." I've tried different carbs to get a good start to no avail. My Dad even fitted the car with manual choke in the 70s (that made learning to drive that much more fun. :rant:) So, all in all, if Jim sez the choke won't work - I'm inclined to take his advice, especially since I had planned to upgrade to EFI sooner or later anyway.

The system Jim recommends in this email is this: http://www.fuelairspark.com/ezefi/default.asp

When I asked if there was anything else to consider he mentioned the sequential fuel-injection upgrade by Mass-Flo. http://www.massfloefi.com/mass-flo-systems-buick-c-1_5/buick-400-430-455-efi-system-p-2. (http://www.massfloefi.com/mass-flo-systems-buick-c-1_5/buick-400-430-455-efi-system-p-2)

Both systems have good reviews. There is a very favorable thread on the EZ-EFI system here on V-8 Buick: http://www.v8buick.com/showthread.php?t=181640. I couldn't find any reviews on Mass-Flo on V-8 Buick but there is this thread: http://www.v8buick.com/showthread.php?t=227223 and there are favorable reviews elsewhere on the web such as this one: http://www.bangshift.com/forum/showthread.php/17653-Mass-Flo-EFI (since the car in question is a 65 GM wagon - to be taken very seriously!! :laugh: )

Both systems have an advantage that they are self-tuning. That turns out to be more important than it otherwise should be. The engine will be installed by a crew who know BMW, Porsche, and that sort of EFI, but EFI for classic GM . . . not their forte. So for me, it's important.

Now the usual gripe about :dollar: applies, but since this is a new engine, the EFI systems provide engine components that would have be bought anyway, so the tariff isn't as bad as adding an EFI system to an existing engine. For the EZ-EFI system I'm look at an extra: $1400, for the Mass-Flo is goes up to $2600 (not including fuel system modifications.) Considering how much I'm already spending on this engine (and that's on a purely need-to-know basis only! :shock:) it isn't that much more to spend.

So all you high-tech for old Iron gurus - what you'all think? :idea2:

I'm willing to consider other suggestions . . . . however, keep in mind that: 1.) I've gotta pay for it, 2.) Jim has to be happy to install it! 3.) the crew at Orinda Motors have to make all work in the end!

Any and all pearls of wisdom are as always greatly appreciated! :TU:

Thanks you all for being a great resource! :3gears:

Cheers, Edouard :beer

P.S. I'm planning on going with an in-tank fuel-pump. Research on that end of this caper is on-going.

[Golden Oldie 65]

Cheap and easy solution.......a manual choke. You can control it any way you want, cold or warm. I would expect to pay no more than $10 for the cable kit. What's an EFI go for, $2,500? That would be an easy decision for me.

[scott kerns]

Gessler can't convert this to electric choke? If not definitely manual choke. Either aren't a big deal.

Scott

[elagache]

Hi Bill (and V-8 Buick lovers, )


Cheap and easy solution.......a manual choke. You can control it any way you want, cold or warm. I would expect to pay no more than $10 for the cable kit. What's an EFI go for, $2,500? That would be an easy decision for me.

What! and relive all that high-school trauma of learning how to drive with a manual choke! Why the therapist costs alone will go way over $2500!! :laugh:

Seriously, the goal here is a very drivable car that gets really good gas mileage and can "compete" with them modern SUVs at the campground (as much on looks as anything else! :cool:)

If I hadn't been interested in EFI anyway, you are absolutely right - somehow get a choke to work. However, I always wanted to upgrade the car in this way. I had only intended to go with the Q-Jet for a year or two and then upgrade (admittedly hoping for another serious gas mileage boost, but now having something to compare it with.)

As noted, this engine isn't exactly cheap. A manual choke on an engine with stage-2 aluminum heads . . . . the word tacky comes to mind.:rolleyes:

If I wanted to just pinch pennies, I'd rebuild the 300 and go on. However, I'd doing something special for my beloved Special . . . and she's worth it! :grin:.

Still your advise is very prudent :Smarty: - it's just a little too late in this caper! :grin:

Cheers, Edouard :beer

[TheSilverBuick]

To me it'd be a no brainer if you planned on using a Q-jet, I'd get the electric choke as mentioned. Before the EFI conversion on my T-bird I converted it to electric choke because in the middle of winter the choke would kick on after extended highway driving due to to the cold air cooling the intake.

On the EFI, between the Mass-Flo and the EZ-EFI, I'd go EZ-EFI. As Jim mentioned about the fuel economy, he doesn't know the guy's carb tuning skills. My personal observation has been most EFI tuner's really don't know their way around a carb very well, particularly on the part throttle efficiency side, since most "performance" carb tuners are really only interested in WOT and maybe transistion accel shot. The really good carb guys that become EFI guys are usually really good EFI guys, can't say it's the other way around.

[Nothingface5384]

well if you decide to go efi and need a fuel pump and regulator pm me

[Ken Warner]

I've been happy with my EZ-EFI system. Have had it on the car 2+ years and several thousand miles now and could hardly be happier. Cold start is great and since FAST released V3 of the tune the cold start needs almost ZERO learning. Something very important to me was hot start is also nothing but a turn of the key no. I don't know that economy is any better or worse than the 950HP I had on my car before.

Biggest issues I see over at the FAST forums with these systems (which seem to be the same issues people have with other EFI systems)
1 Installing sensor/power wires near plug wires (noise)
2. A clean tach signal is a MUST (MSD is the clear favorite here)
3. Power and ground need to run off the battery.
4. Make sure your "system on" wire has good voltage during cranking.

If you have any specific questions please let me know.

regards

[TheSilverBuick]

Ken hit it right on the head for general good practice EFI installation.

1) Buick's make this relatively easy since the spark plug wires start in the front of the engine and wrap around the side.
2) All efi systems want a clean signal, some systems have better signal filtering than others though.
3) I run my megasquirt's main power and ground from the battery, but each sensor is grounded individually to the block.
4) A problem I had early on is finding a power source that was there during cranking and ON but no power while OFF. On the '67 T-bird I had to do some tricky wiring with a relay to make it happen, the '77 Skylark had a fuse box source that worked perfectly.


Depending on your intake, the SPX and a standard 1,000cfm throttle body isn't any higher than an Edelbrock Performer and Q-jet, and the electrical routing was conviently away from other car electric circuits. All the EFI wiring runs through those two harnesses, one for the injectors and the other has the coolant temp(2 wires), air temp (2 wires), tps(3 wires) and tach (1 wire). Unplugs from the connector on the firewall. Simple.
http://c4.ac-images.myspacecdn.com/images02/60/m_50f6a8bb385c4302948b3f1811a6d517.jpg

[theone61636]

You've already stated that your Buick is special and deserves the best so why even bother with a TBI setup? I take it you don't really want to ever mess with the tuning aspect of it so really the self learning requirement shouldn't be one. Get a stand alone MPFI system, find a tuner, and have them dyno tune the engine first and then refine the tune on the street. Sure, it will cost more, but if you want EFI, do it right the first time.

But, after saying all that, I'm with the others that have stated to convert to an electrical choke and be done with it. Then you can spend all that extra money you saved else where.

[pmuller9]

Remember, if you're going for total fuel economy as well as performance then you need spark control, period. The EZ doesn't have it, The PJIII doesn't have it and the Mass-Flo only alows 20 degrees of adjustment.
Only Holley and Accel throttle body systems give you that perk.

Thanks

Jmo.

I just got off the phone with Mass-Flo and according to them
their system starts off with an initial timing of around 14 degrees
and maps well past 20 degrees beyond that.
Please explain what you meant.

Thanks

Paul

[elagache]

Dear Jason and V-8 Buick members,

Apologies in advance to those who don't fully appreciate my predicament, but I didn't want this thread to become a "turf war" of EFI versus carb, or which flavor of EFI is the best. This is a particular case and this decision needs to fit my unique constraints.

For starters, the car is in California, the engine is being built in Minnesota, and the transmission is coming from New York. So seemingly obvious suggestions like Jason's aren't so straightforward:


Get a stand alone MPFI system, find a tuner, and have them dyno tune the engine first and then refine the tune on the street. Sure, it will cost more, but if you want EFI, do it right the first time..

The engine will assembled and first dyno tested by Jim Weise in Minnesota. Then it needs to be put into my car in California. That means two EFI tuning gurus separated by thousands of miles. This isn't simply a matter of more money, it's much more hassle for me and will I have a well-running engine in the end?

The other point that seems to be overlooked in this discussion is that I'm almost building a new drive-train from scratch. Sure there is an additional cost to going EFI. However, the alternative isn't free. This engine needs a distributor, intake manifold, carburetor, and fuel-pump. If I have Jim assemble the engine with a carburetor, I would have to "throw-away" those components to switch to EFI later. The car even needs to have its fuel line replaced because the existing line is too small for a big-block V-8. Do I really want this fuel line replaced and then redo this again for fuel-injection? So this is a significant fork in the road and no easy way to go carb now and upgrade to EFI later.

Finally, critical differences in the technology aren't getting their proper consideration. The Mass-Flo system operates differently than most aftermarket EFI systems. The difference is described nicely in this Chevy High Performance magazine article posted on automotive.com: http://chevyhighperformance.automotive.com/81850/0705chp-mass-flo-efi-system/index.html

Here is a quote from two key paragraphs of that article:


Any naturally aspirated engine, regardless of brand, size, or combination of parts, requires a given air/fuel ratio at a given load. These ratios do not change from engine to engine, until you get into forced-induction applications. (We'll get to that later.) The needed air/fuel ratio changes with such things as engine temperature, air temperature, and atmospheric pressure, and the changes are the same for all engines. The task for any management system is to add the correct amount of fuel to the air the engine uses. Carburetors do it mechanically, so accuracy is limited. Speed-density systems do it by comparing the readings from various sensors to tables within the engine controller to determine the amount of air the engine is using. This actually works very well, if the values in the tables are correct, and therein lies the challenge. A professional tuner is required to enter the correct values into all of those cells in all of those tables. The next step is to drive the vehicle in the real world and adjust those values to tune out all the drivability issues.

. . .

Mass-Flo does it differently. The MAF meter can measure the amount of air entering your engine, and again, if you know how much air the engine is using, then you just add the correct amount of fuel. It's that simple. The air/fuel ratio is adjusted accordingly to compensate for the load and variances in engine temperature, air temperature, and atmospheric pressure by reading values from the sensors. If you decide to upgrade your engine, Mass-Flo adapts to those changes. Remember, an engine is just a big air pump, and changing heads, camshafts, intakes, exhaust systems, and displacement are just ways of making your air pump more efficient (use more air). With speed density, it's back to the dyno to start all over again

These differences in EFI systems are described generally in this article on the Ford Fuel Injection website: http://fordfuelinjection.com/?p=4. The Mass-Flo system is based on the Mass-Air-Flow technology developed by US auto makers and used commonly in the modern cars most of us are familiar with. So the self-tuning strategy of Mass-Flo is genuinely different and therefore has a fighting chance to match professional EFI tuners.

The Mass-Flo system appears to have some genuine limitations, especially in racing, where some software adjustments seem required. However, that isn't surprising considering that this Mass-Air-Flow versions of EFI was developed by auto makers to optimize gas mileage and reduce emissions.

I made another search of these systems on the Internet and overall there are happy owners of both the EZ-EFI and Mass-Flo system. There are more happy EZ-EFI owners out there, but that's hardly surprising given the price difference.

Once more, given my predicament of having to "cobble together" a car from components traveling thousands of miles, some sort of self-tuning system seems all but required. If I want to go with EFI eventually, perhaps I'm truly better off to bite the bullet now than to have to redo a lot of work in the future.

So that's why I came to you'all for advice. Our classic cars most certainly aren't "one solution fits all." Still for this thread, I would appreciate if folks could focus their suggestions on my problem!

Cheers, Edouard :beer

[TheSilverBuick]

Your problem would be solved by an electric choke OR jumping into the deep end with one EFI package.

A fuel line sufficient for a carb is sufficient for EFI, HOWEVER, EFI would like a sump or surge tank for when the fuel level get's low. I run a 3/8th fuel line on mine with a 5/16th Ford pump and can still manage a sub 10:1 AFR at WOT and 5,000rpm on roughly a 400-425HP engine. Plenty of wiggle room, I am going to attempt to run the same fuel system with the new engine combination. I also run a 5/16th return line to the gas tank. I actually think the EFI is less sensitive to fuel line size because you can play with the pressure much more with EFI. I'm currently at 43psi and have no issue taking it up to 60psi.

If your car has an OE return line, it'd probably be real easy to convert later. The return line was the biggest job of plumbing the EFI. I went with a surge canister instead of a sump so I didn't modify the gas tank at all and several times have ran it down to a gallon or so left in the gas tank with no noticable effects.

[theone61636]

Not sure if I missed it but what are your goals for the car? You've mentioned pieces of your engine build, but never really came out and told us what your engine is being built to do.

Honestly, not being able to get a choke to work seems like a poor excuse to spend a bunch of money on EFI if is wasn't originally part of the goal.

As far as the tuning goes there's no reason why Jim can't dyno tune the enigne with the efi system. In all honesty, this will be the 95-98% solution. Once the engine is bolted into the vehicle, wiring harness attached, and fuel system completed, you start it up and drive the vehicle. Whatever small hiccups or nuances you feel need attention, you could find a competent tuner in your area and hook him up with Jim's info so they can communicate and share the maps developed by Jim during the dyno. Then the tuner will have you drive your car around while he irons out any small discrepancies noted from your drive. A good street tune should cost no more than 250-300 dollars if that.

My only suggestion concerning EFI, is if you're going to do it, go with MPFI. Self learning or not, if you want the best performance, go MPFI.

[elagache]

Dear Jason, SilverBuick, and V-8 Buick lovers,

Sorry to those to have already heard the story before, but indeed I don't have a good spot to point people to, so it somewhat my fault.


Not sure if I missed it but what are your goals for the car? You've mentioned pieces of your engine build, but never really came out and told us what your engine is being built to do.

This engine is going into a 1965 Buick Special wagon that has been in the family since 1968. The goal is to bring back the glory days of the American station wagon. That includes the mundane chores like fetching the groceries, but to me is especially as the vacation cruiser. So the key objectives are: 1.) an increase in torque and horsepower that would allow the car to comfortably tow a 5000 lbs load, and 2.) as great an improvement in gas mileage as modern technology can "graft" onto a period Buick engine. The car will definitely never race, but my hope is that it will give SUV and RV crowd something of a shock when my wagon pulls into a campground with an Airstream trailer.


Honestly, not being able to get a choke to work seems like a poor excuse to spend a bunch of money on EFI if is wasn't originally part of the goal.

Indeed I think Jim is "stretching a point" but what lies between the lines is very much in my interest and a matter of his own reputation as well. Can something be made to work with the Quadra-Jet? Obviously yes. However, this is going to be a really incredible engine. Moreover it is an incredible engine of the sort that basically aren't made. People spend tons of money for racing engines, not for engines to revive classic cars for seemingly "everyday uses." It's a chance to take a classic car and really make it practical for today's world. I think it is a goal worth pursuing and if I'm successful it may change a few minds about what a classic car is really all about.

Given that goal where should I stop when it comes to modern technology? My original plan was to go with some sort of EFI system. Ironically, it was Jim himself who discouraged me by an engine he built with very good gas mileage using a Quadra-Jet. In a thread where you made very similar suggestions: http://www.v8buick.com/showthread.php?t=220954, Jim mentioned this particular engine build: http://www.v8buick.com/showpost.php?p=1789380&postcount=27. However, that wasn't engine built with the same goals as my engine and its fuel economy was a "lucky accident." Now that Jim has a purpose-built thifty engine project on his hands, his own approach to the task has evolving and I'm inclined to agree with him!


As far as the tuning goes there's no reason why Jim can't dyno tune the enigne with the efi system. In all honesty, this will be the 95-98% solution.

Sure, that might work fine. However, as I have read up on this topic, I'm impressed with the underlying technology of the Mass-Flo system. It definitely isn't for everybody, but given my goals of high-fuel economy, it seems more robust at insuring fuel isn't wasted. If major auto-makers are using the Mass-Air-Flow system for maximum fuel-economy, that looks like the right mouse-trap given my particular goals.


My only suggestion concerning EFI, is if you're going to do it, go with MPFI. Self learning or not, if you want the best performance, go MPFI.

You're tempting me again . . . . . and I didn't need any help!! :grin:

Cheers, Edouard :beer

[TheSilverBuick]

Self tuning systems always leave room for improvement on power AND mpg's cause they have to play it safe, particularly when they only self tune fuel and ignition timing plays a HUGE factor in mpg's. I screwed with fuel for essentially a year and was capped at 17 mpg, exactly the same as what I was getting with the Q-jet. Then I advanced the timing ~5 degree's at cruise, which let me go leaner, and I gained 2mpg consistently. From a repeatable 16.5-17mpg to 19-19.5mpg tracked over thousands of miles. So self tuning EFI is only as good as your ignition tuning (rather the ECM is controlling timing or no).

[sean Buick 76]

These guys are all right with the points about fuel economy and the limitations of the systems you are talking about.

Can the EZ EFI system give you datalogging information so you can use your laptop to tune? I am pretty sure the answer is no.

Like others are saying if you want the best fuel economy possible then go MPFI and have the system tuned on a chassis dyno. Jim can dyno your engine with a carb, no issue there and then just add the EFI and pay for the tuning. If you are not willing to do what I suggest then simply us a Q jet that works with an electric choke and enjoy.

I am getting 21 US MPG with a Q jet and the car is over 4000 pounds, plus my average highway speed is 70-85 MPH. Do I think I could get better fuel milage with an EFI system on my car? Nope, not likely.

The only reason I am going with MPFI on my Skylark is so that I can control and datalog everything since I have turbos and want to get 100% out of the engine right on the edge of blowing it up. Using all the data I can sneek up on a perfect tune, but it takes work.

[bobc455]

If you decide to go with EFI, have Jim do a *complete* cam break-in. An FI system can be finicky to get started, and you don't want to risk a cam melt-down due to improper break-in.

In fact, I would even ask Jim to break in the motor with a carb (he probably has the ability to do this), and leave the FI system to be added afterwards. I did run my FI car on a carb for a while just to check for a problem- you only have to replace the throttle body with a carb.

-Bob C.

[Jim Weise]

Guys,

It's not that we can't get a choke to "work".. but then again getting the car to cold start, and getting it to start up and run perfectly, under all the possible temp conditions is another thing all together. The vast majority of us don't drive our classics as everyday cars, and I think it would be stretching the truth for any of us to say that their carb car starts and runs, with immediate "drive off" ease, under all conditions.

There are also two other factors that complicate the issue.

Obviously we can tune a carb for an efficient fuel delivery, knowing the fuel requirements and a standard set of operating conditions, of which, altitude plays a big factor.

But this customer lives in California, and plans on using this car as both a daily driver, and also to go on trips, and as all you Californians can attest, it's not out of the question to go from sea level or below in the Desert, to several thousand feet in the mountains. So the best I could do, and maintain a safety margin against detonation, is to pick a "safe" fuel curve, which will in fact be a touch fatter than optimum for mileage.

This is also another consideration for choke operation.. break your manuals out and look at the different choke settings from back in the day, for "altitude".

Secondly, add in the complication that he is going to be towing a trailer, thus loading the engine far greater than just what it takes to move the car along, and we now have a serious concern, as this makes detonation much more likely.

These considerations lead me to believe that for this individual customer, some type of "on the fly" adjustable fuel delivery system would give him the best overall experience, in both "start and drive off" ability, as well as overall fuel economy. Under all conditions.

Another consideration is cost.. sure a whiz bang, bells and whistles MPFI system would be the best option, with it's own dedicated EFI manifold, but at what cost? Attaining one or two MPG, vs the cost of most of the systems out there that fit this description, is simply "penny wise and pound foolish". You can buy a lot of gas over the years of service for this vehicle, for 3 or 4 thousand dollars. Also, as was mentioned, this is being built to be a low rpm torquer, so a single plane carb intake, which most MPFI systems want, is not consistent with that goal.

The Fast EZ-EFI system is now at a price level, where the discussion is reasonable. Most everything else on the market, is still priced up beyond a point where there you will see any real savings, because the high cost of the initial install, will wipe out any savings on fuel, for many, many years to come.

I strongly believe that the new 8552 MSD distributor, with it's adjustable mechanical and vacuum advance capabilities, will fit the bill nicely for the requirements of this build, it is only lacking in the ability to retard the timing when required, when compared to EFI controlled timing. So we have to set both the initial and the curves a little more cautiously than you would with a system that can retard the timing when required..

But, regardless of what is sitting on top of a given engine, they only want so much timing, to run efficiently. For a BBB that's 32-34 degrees for power, and 42-48 degrees, for mileage under light load.

JW

[TheSilverBuick]

Guys,

Obviously we can tune a carb for an efficient fuel delivery, knowing the fuel requirements and a standard set of operating conditions, of which, altitude plays a big factor.

But this customer lives in California, and plans on using this car as both a daily driver, and also to go on trips, and as all you Californians can attest, it's not out of the question to go from sea level or below in the Desert, to several thousand feet in the mountains. So the best I could do, and maintain a safety margin against detonation, is to pick a "safe" fuel curve, which will in fact be a touch fatter than optimum for mileage.


This was the main driver for my conversion. And now I live at 6500ft, work at 7,000+ft, and regularly road trip to sea level back in So. Cal. I can attest to 20% measured difference in air pressure from my house to my Dad's house in southern California, and you know that's changing things up!



Another consideration is cost.. sure a whiz bang, bells and whistles MPFI system would be the best option, with it's own dedicated EFI manifold, but at what cost? Attaining one or two MPG, vs the cost of most of the systems out there that fit this description, is simply "penny wise and pound foolish".

I've been told by two groups of people I trust with EFI testing that the throttle body systems have poor fuel distribution issues when compared to MPI (based on 8 cylinder WBO2 sensors or EGT sensors), so you are always tuning to the leanest cylinder. Of course if you don't get your injector's flow balanced, you're doing the same with with MPI too. That all being said, I'm not sure where a carb falls in the distribution spectrum, I suspect better than TBI's from fuel atomization, but not as well as mulitiport distribution.

That's just my non-professional, being a car guy, opinion.

[TheSilverBuick]

But also be aware that some systems i.e. PJIII do not have a barometer or only have them able to change calibration by cycling the key on and off. Try that driving while down a mountain.


Most systems use a closed loop O2 sensor feedback to keep AFR's in the target range (a target AFR based fuel table), and usually the system allows the O2 feedback to adjust the fuel table around 15%-20%, the self learning systems especially are like this. The side benefit is that going from the top of a mountain (80kpa) to sea level (101kpa) (or the reverse) the system starts to lean out and the O2 correction act's as the barocorrection. It's not a perfect system because backpressure on the exhaust changes with elevation too, but it works fine 95% of the time.

[TheSilverBuick]

A barometer won't solve the problem unless the baro-correction factor has been tuned for the car. That correction factor is effected somewhat by intake and head design, largely by cam design (namely volumetric efficiency) and largely by exhaust design (dual, single, 2", 3", etc). So a baro sensor is useless unless the owner can calibrate it. I calibrated mine using a table by adjusting the correction factor as I drove down the mountain until my AFR's were the same at the same load/rpm. There is a linear calculation that works pretty good too, but figuring out the two numbers you need to plug into for the correction factor can be difficult to calculate (at least for me...).

Basically I don't use a closed loop O2 feedback, as I much prefer to have my baro-correction table made up, but I have in the past used the O2 feedback to correct it, and it works okay. Most people I don't see taking the time to drive dozens of miles or more to calibrate their table for their car. Most are interested in plug n play.

The axis of my table is a bit funny because I do 90% of my tuning at 80-85kPa atmospheric pressure rather than a 101kPa sea level, but it functions the same.

[TheSilverBuick]

So what you are saying is after you drive around your home town for a bit and it's all tuned up, you can cut the O2 sensor wire, and drive from Florida to Alaska and your Accel system won't have any problems with elevation for any application? I'm "highly" susupicious of that claim. Every system I know of might have generic calibration air density correction factor to get it in the ballpark (most only set it when it's turned on as they don't come with a second MAP sensor to get an on the fly reading) but still rely heavily on the O2 feedback for final AFR trimming, because it's cheap, easy and quite effective for 95% of engine combinations and driving situations.

[Ken Warner]

First off, great thread-jack guys.....

Back to the problem at hand... you were looking for an easy solution.

Before you jump ship on the carb you could try the divorced choke anyway. The intake is still gonna warm up. I'm betting with some fine tuning you'd get by. You might get away with just having to adjust it a couple times of year.

Unless something has changed over the last few years I don't think you are going to get a pre 1975 Buick Q-jet (performance friendly) that can be setup for an electric choke. I did see a guy out of Dayton Ohio that had some sort of choke from a Mopar application mounted on his intake and it was electric. Maybe someone has a line on these.... Perhaps someone on the FAST forum would know? As an alternative if you want to stay Q-Jet maybe a Cadillac or Pontiac carb would be possible. Even if you have to have a carb built it will be cheaper than going to fuel injection.

If you decide to go F.I. then you have several choices of TBI based systems from the likes of FAST, Holey and Pro-Flo. At the very least you are going to have to upgrade the fuel system and run a return if you don't have one already. Without spelling it all out everything costs money here and usually more than you plan. This thing can easily snowball into a tank, an intake (or at least the machine work for it) the kit with rails etc then you start looking at tuning the system ($$$$), and what about that old dizzy, is it going to have to be replaced? Will the system you look at need a crank trigger??? ($$$$$)

IMHO if you want to keep this easy and save some cash there has to be a BOP (Caddy?) Q-Jet that would allow you to use your existing fuel line and look at least "pretty stock" as long as the air cleaner is on. The Q-Jet will give you solid metering and good fuel economy if you get it built right. Seems like there is a Q-Jet guru on the board in the mixing shop section out of the Cleveland area. Look him up.

Either way let us know what you decide. If you do have any additional questions regarding the EZ-EFI drop me a PM and I'll be happy to chat.

[Jeff Peoples]

I have EZ-EFI on my Stage 2 GS. Before, I ran an HP950 in the summer and at the Nats. In the winter, I changed to a 750 vacuum secondary with an automatic choke. Both carbs were tuned for idle and part throttle cruise with an Innovate Motorsports wide band O2 meter. I had to lean them both considerably from their out of box state to get any kind of economy at all.
When I set up my car for autocross with new suspension and disc brakes, the carbs didn't like all that sloshing around, and would often go dead under braking. I had the floats set up for the drag strip, and that was the end of my rope on turning another wrench on the carbs!
I put on the EZ-EFI and haven't looked back. What attracted me was the self-learning, and a decently affordable price. If I had gone straight to the EFI, I would have saved allot of money and hassle tuning on the carbs. The HP950 was over $700! Now I have more power, no stumbles during cornering or braking, super throttle response, and nice eye candy too.
The response is so good, the v-belts will squeak when revving the motor in neutral. My reaction times went from 0.570 to red lighting, in a car weighing 4100 pounds with a 2600 rpm converter. Also, I am now picking up the left front wheel about an inch. This with tight suspension and 17x8 255/40 front wheels and tires.
I would recommend the EZ-EFI to anyone wanting to experiment with EFI, without having to get in too deep with fuel maps, timing, etc.:Smarty:

[bobc455]

Mark,

I've been running my Speedpro system for about 10 years. I've been running without the O2 sensor for about 6, after I decided my tune was perfect (=<3% correction about 99% of the time).

I've driven the car a lot of places since then- not quite the elevation of the rockies, but through some pretty varied terrain.

Can you explain the benefit of a baro sensor, in comparison to a MAP-based system with no baro correction? Seems like as long as you have the system tuned to give correct fuel based on manifold pressure, barometric pressure doesn't bring anything to the game (unless you were to use it to trim back the AE vs. TPS enrichment).

Just curious.

-Bob C.

[TheSilverBuick]

Can you explain the benefit of a baro sensor, in comparison to a MAP-based system with no baro correction? Seems like as long as you have the system tuned to give correct fuel based on manifold pressure, barometric pressure doesn't bring anything to the game (unless you were to use it to trim back the AE vs. TPS enrichment).



I'm not Mark, but that was my line of logic when I first started in with the EFI. "As long as the system knows the air temperature and has a baro-reading in the intake (MAP) then it should be good". But the reality of physic's is that it doesn't quite work that way for a couple reasons. One thing is that with elevation not only does the air pressure just drop because less weight on it (air above), but the density of the air is less, and using only pressure and temperature to measure the density doesn't account for changes in the weight of air above, it uses the air pressure of where you are when you start the car as a reference for "current" density, then calculates the air density in a vacuum based on pressure and temperature changes. If the outside air density changes, the computer/formula needs a new reference. As in if the air density increases outside the intake manifold (going down hill), that means more air is getting in, even though pressure in the intake will actually change minimally, but it will lean out the AFR's. Take the equivelent example and and replace air with water, you can go from deeper water to shallower water and the pressure will be less, but the water density will be the same. So what the system needs to correct for is change in air density as the pressure decreases, and temperature as the only other variable to pressure doesn't do it quite perfectly. The key is to remember that pressure and density are not one and the same for air, they are related but not the same.

Another reason also related to pressure and density is exhaust backpressure. I don't know all the theories to backpressure, but I know the OEM's take it into account and supposibly(I've never fact checked this one) the avaitation industry, particularly hobbiest with piston engines, take it into account. So that's why it's a correction factor and not a straight barometric change. I'm sure all EFI systems have a baro correction factor, it's just a matter of how close is it calibrated to your set up. Close counts probably 90%* of the time (*warning: made up statistic :Do No: ).

I run with out the O2 doing anything except reporting the AFR, it doesn't correct anything (which was handy when the LC-1 was out for three months last year..), and early on before I had my correction table set up my system would get a lean miss about every 1500ft drop in elevation, where I'd plug my laptop in, fatten up the fuel table until the AFR's were normal then do it again at the next drop. Until I figured out how the barocorrection table work I had a tune for every 1500ft elevation :spank: So going from 6500ft to 200ft in a single trip was rather entertaining. Now on systems with out a second MAP sensor (baro) I'd have the same problem, because though they have a correction table, they get the correction factor from the initial reading of the MAP sensor before vacuum is applied to it by the engine, so in theory every 1500ft I'd have to turn the car off and simply restart it and it would be good. A second MAP sensor just left open to the air lets it take an "on the fly" reading so I don't have to do that. MOST systems use the O2 as an AFR feedback, so if I had my turned on, as I drove down the mountain, as the AFR's leaned out the O2 feed back would of been fattening up the fuel mixture and I would never of gotten the lean miss. In fact that's what I did prior to figuring out how to set the baro-correction table. Figuring feedback systems allow for at least 15% correction, that's about sea level to 5500ft elevation or so with normal weather, and I'd bet the self learning ones allow much more than 15% correction. Also in most people's cases, going up in elevation causes the mixture to go rich, which is much less noticable than going lean. So if you are tuned nice and happy with a 14:1 AFR and climb up to 6,000ft elevation, the engine would then be running around 12.5:1 if there is no correction. Engines are plenty happy running that fat for regular driving. It's not optimal, but from a drivability stand point you wouldn't notice it nearly as badly as going to a 16:1 or leaner AFR, so the elevation effect isn't as noticable to you low lands folk :pp

This is my experience and understanding of it.

[elagache]

Dear V8 Buick high-tech aficionados,

I thought I should wind down this thread with my final decision for the engine that Jim Weise is building for my 65 Buick Special Wagon. Ultimately, I prefer the "middle road." I'm sure that a Quadra-Jet would have been perfectly satisfactory, still it is not as pleasant especially when taking the car through extremes of altitude and weather which I hope to do while traveling.

I tried to get in touch with the Mass-Flo folks but unfortunately they were on vacation last week. I had sent them an email asking them for a reference of someone who had successfully installed their system on a big-block Buick engine. Their reply was hardly friendly. All other arguments aside, I couldn't consider Mass-Flo unless I knew other folks had made it work on a big-block engine and were tickled-pink by it.

So that leaves the various Speed-Density systems and the tricky problem of self-tuning or not. However, this matter again was resolved by a mix of my unique conditions and user recommendations. I'm interested in eventually going full-blown sequential fuel injection, but with components thousands of miles apart - this doesn't look like the right moment to try. With too many cooks in the kitchen, I'm likely to have a hard time getting things to work. The right way to go MPFI is to get the car to work - first! Then I can be greedy in a phase #2 upgrade.

The remaining selection is made easy by the recommendations made here and elsewhere. There are a number of happy Buick users of EZ-EFI and Jim is comfortable installing this technology. The difference in cost is modest and the fuel system upgrades are required for other reasons.

So I'll start with this scheme for now. As noted, my reasons are very much unique to my predicament. Someone who can have all the work on their car done locally has many more options, especially if you have a dependable local EFI-tuner. However, with an engine thousands of miles from the car - for me it just isn't that simple - none!

Thanks for all your help with this and . . . please do help me decide on a fuel system to go with it!
http://www.v8buick.com/showthread.php?p=1894470#post1894470

Cheers, Edouard :beer

[TheSilverBuick]

The Q-jet will serve you well, and when set up at 1,000ft or less, you'll notice only a minimal difference in power at elevation when it runs a tad richer, nothing harmful.

Follow my Skylark thread or my Distributorless thread for work I'm doing on my 455's EFI/Ignition. I'm not going full blown sequential fuel injection, but it would just be a matter of switching the MS2 for an MS3 or other suitable SFI capable ECU because I'll likely have all the hardware installed to do it (crank trigger and cam sensor).