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.
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
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! 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.
Remember, any TBI system will have some of the same inherent defficiencies a carb did, it's on the same manifold. It's really just an electronic carb. 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.
Why not just get a system that has a barometer in it, problem solved. Also when going to EFI, yes the O2 will help keep afr's in check but the better systems have a higher sampling rate, therefore enhancing running quality, especially on a TBI.
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.
Categorically I believe you're wrong, I can only speak for the Accel but it already has the table calculated for standard baro changes. On top of that you can change the calibration for other variables. It's just like their Nitrous table, plug in the pill size and number of pills, then bottle prsssure and it does the fuel curve for you, and it'll be real close to perfect. That's what I mean by making sure you have a system that fits your needs. For the record, Accel incorporates a lot of OEM stuff, for example if you were to drive your new Lacrosse from Florida to Alaska thru the mountains of Wyoming you would expect to have no issues correct? The Accel will do that, a lot of others won't, plain and simple.
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.
Here you go; A few years ago I did a 383 Chevy in a Jeep. He and his buddies routinely go to the mountains in Colorado. A couple of the guys had an Edelbrock Pro-Flo systems on their Jeeps initially. They were tuned in Fl. By the time they went to Colorado they spit and sputtered all the way up the hill, that's what prompted a change. We put a Gen 7 with a narrow band on one of them, the other Jeep still had an Edelbrock. Guess what, the Gen 7 left the Pro-Flo in the dust, so the answer to your question is yes. And it changes on the fly. That's why there is one drawback, by having the barometer inside the box, you can't seal it. I have a couple of boat guys wanting to use a Gen 7. It's o.k. as long as the don't trailer their boats from here to Tahoe. I guess they'll have to unseal then seal it again. I mentioned the Accel has a lot of OEM stuff in it, this is part of it.
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.
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:
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.
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 o 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 p This is my experience and understanding of it.
Will start with EZ-EFI and then . . we'll see! (Re: Jim "sez" EFI) 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
Re: Will start with EZ-EFI and then . . we'll see! (Re: Jim "sez" EFI) 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).
