Okay....so I just read through 3 pages of EFI talk that made my brain mad at me. A lot of it made sense...but I still feel like I have basic questions unanswered. Let's say I have a 455 or a 425/401 that I wanna play with. Let's also say that fabrication is one of my stronger points. Drilling and welding in bungs for injectors and rails....no problem. Converting a carm to a throttle body.....I think I can do it. http://www.mez.co.uk/ms2.html Now the electronics part is where my questions remain, and I am looking for some pretty simple answers. I've already read every word of this... http://www.v8buick.com/showthread.php?241628-Which-Fuel-Injection Now....say the fabrication part is all done and I'm ready to do some wiring. Can I use a harness and computer from a MPFI V8(say a 454 just for discussion sake) and reprogram it to work for my application? Second part of the question....is it worth it as far as fuel efficency gains? My next project is gonna be more "cruiser" based. I still want to be able to smoke the tires here and there, but I'd also like to drive it long distances. If this much work and effort is only gonna get me +2 MPG.....not worth my time for sure. At that point....I begin wondering if a LT1 from a donor roadmaster would be worth the effort. My ultimate goal is to take a 50-53 Super or Rivi, and make something that can both smoke some rubber when I want, but also not cost me a small fortune in gas. I already have this '72 455 in my garage that I'm willing to play with.... and I would definitely love to make her injected. But as I stated before....if the gains aren't substantial...I'm not sure it's worth my time....... Discuss!
You want multipoint injection to see the biggest increase in mileage and power. That means the throttle body will just be used for air and the fuel lines will go to the fuel rails via a regulator. The elctronics are the hardest part since your engine doesn't have a cam or crank sensor. The other sensors that you need can be found at the local junkyard and wired in easy enough to whatever ecu you want to use. The cam sensor can be snatched from a later 3.8 that has the distributor mounted cam sensor. Or you can use the distributor from a later vortec van and have it grafted to your Buick distributor shaft which will allow you to have the right sensor specs to run a vortec ecu. The crank sensor is all custom and that's the hard part. If you check someone made up a custom external one and it seems to be working. I know there's also a company that makes a factory style one that gets retrofitted to chevy motors to run the vortec ecu. I asked about a custom install and they said it was a matter of having enough clearence between the crank and the timing cover to fit the sensor wheel.
Wouldn't a points eliminator kit help serve as an optical type crank sensor in theory? http://www.youtube.com/watch?v=RuIislTGOwA Since it's already optically sensing engine rpm, just not timing. Running a carb means that timing has to be set manually anyways. I can handle that. If not....would a hall effect sensor mounted at the flywheel suffice? seems like in that case, a little fab work could have a mount on the bellhousing or even that dust cover.
According to this....on my Xterra the crank sensor is for diagnosis only and doesn't affect how things are running.
Using a stock ECM from the junkyard will disappoint you. 90% of the people I hear complaining that EFI didn't work well for them was from using a stock or re-flashed ECM from a different engine. It's more of a headache than shortcut. I recommend going with an aftermarket ECM you have full control over. You've read my post in the other thread so no point in me re-hashing it. You DO NOT need a fancy distributor or crank trigger to get most these to work. A simple wire from the points works just fine, and if you use the ECM to trigger the coil (or MSD box, etc) then there is almost no wear on the points contact because very little current will go through it to signal the ECM. If you get an HEI distributor you can run some/most ECM tach feeds right from the pickup coil. Or you can do like my TBI'd '67 T-bird and leave the distributor alone and just run a wire from the negative side of the coil and call it done (that won't control ignition, but is fine for fuel control). If you have any sorts of carbueretor tuning skills, particularly with a Q-jet, then you won't gain much in the mpg department if your carb is tuned well. And overdrive transmission will net the most gains for mpg. Figure 5%-10% mpg gains with the EFI if the carb tune is good, 25+% if not tuned so well (Because it's a Holley =P and assuming you can tune the EFI, if you're good with a carb, you'll find the EFI tuning intuitive IMO). Overdrive transmissions are almost always good for at least a 20%-30% increase in mpgs right off the top. That's my two cents.
So basically with a well tuned carb, I could just beef up an OD trans and get similar results with a whole lot less work? (and of course rear end gearing) Now what about this option vs the LT1 option? The car I'm looking at right now has no engine in it anyways, and the plan is a full front subframe swap, rear 4 link and lots of custom fabbing. So...at this point I'm trying to narrow down engine options. If an LT1 is a reasonable option, I might not be opposed to a full mid-90s Roadmaster frame swap.
LT1's are good engines once the Opti-Spark upgrade,to keep water out, has been made. Reliable and make decent power right out of the box. Quick starting and MPG gains are bad reasons for switching to EFI if they are the only reasons because they definitely don't justify the cost. My motivation was operating conditions. I start and drive my car in temps ranging from -20*F to 120*F, and in elevations ranging from 8,000+ feet to sea level. I have a deep overdrive transmission and wasn't happy with the mechanical/vacuum timing settings across the rpm range, and either was setting it for WOT or for cruise, but not quite ideally where I wanted the timing for both at the same time with the low rpm high load cruising (finding the appropriate vacuum can rate and total is a pain these days). Plus I can start a high compression engine with 5* of timing (spins like the ignition is off) and instantly get 20*+ of timing when idling for a smooth idle.
This car, once completed, could very well see altitude changes from 10,000+ all the way down to sea level potentially. Ideally, it would take me from Denver to Flint. So that's why FI became a thought. There's no way a ballsy 455 is gonna be an economical means of conveyence to the mitten. The LT1 popped into my head, just based on the roadmaster's sheer size. Seems like it would be a reasonable match for an early 50s Buick, and if I found a donor Roadmaster, seems like a lot of parts would be quite useful. Beyond an engine even...suspension, transmission, drivetrain, etc..
Coming from the Gen2 world I can say that the LT1 is a good motor. I'm not a fan of that over a generic Gen1 sbc though. Basically the biggest benefit to the LT1 is the head design and the fuel injection. Now that you can bolt the vortec heads to the Gen1 there's not much value in LT1's anymore. The trans is junk that comes in that car too. Stay away from the 4l60e if you can help it. Also they tend to have issues when it comes to grounds and other electrical things. I'd do as Silver says since he's been down the fuel injection retrofit road and speaks from experience.
Have you ever seen this: http://www.bangshift.com/forum/dto_garage.php?do=viewvehicle&v=1072 It's a 1956 Belair wagon on a early 90's Caprice frame complete with LT1, etc. drivetrain. The stock ECM controls the transmission and a MegaSquirt is piggybacked onto the stock wiring to control fuel and spark if I recall right. So I'd say it's a reasonable match Carb's work okay at elevation, they just run super rich if set up for low elevation or lean out if set at too low of an elevation. An example I have, is pulling the Eisenhower tunnel pass outside of Denver, CO. 11,400ft elevation. I pulled it in my Centurion with a 455, Q-jet, points,no OD, 2.93 gears, and could barely run 40mph because the tune was so far off. I had all the barrels open, but there just wasn't enough O2 or air pressure to make up for the load. I've pulled steeper summits at lower elevation with zero issues before. Then last September, I drove my Skylark, EFI'd 455, fuel and ignition, deep overdrive, cruising at ~2200rpm, pulled that pass at 75-80mph no sweat. I was up around 50% throttle and AFR's stayed right where they should for good power climbing the summit. Logged the barometric pressure at 64kPa, which sea level is at 101kPa, so 36% less air pressure. So it just depends how often you'll be seeing those swings in elevation. A carb will function, but not optimally.
Heading west from Denver is a definite. So yeah....Eisenhower and Vail pass will get me way up. As well as headed to Michigan and getting down to 500 feet and possibly lower. It's gonna see an extremely wide variance of altitudes and air densities. From everything I'm reading, however, it seems that there wasn't really a Buick specific LT1. Just a generic GM package. I really don't wanna be the guy dropping Chevy stuff into a Buick!!
For an LT1 you would become "THAT" guy =P lol. Again, a carb won't leave you stranded on the side of the road, but they can get pretty cranky covering that elevation. I live at 6,500ft elevation, work above 7,000ft, Vegas is the next town south at 2,500ft and "back home" in California is around sea level. Several times a year I'm driving off this snowy hill through the blazing desert and to the sea p
One of the next engines Jim Weise will be completing is a high torque BBB for a 65 Buick station wagon with fuel economy as the main goal. The most important component of this project is the overdrive transmission with the lock-up converter. This engine will also be EFI. Paul
I'll be interested to hear how that goes. I've been at an impasse getting to 20+mpg. Stuck at 19 =/ I just installed a narrower tire on the car with a more road friendly tread pattern, so hoping to see some gains next time I leave town. I had a lighter '69 Firebird with a weak 400, 700r4, 2.73 gears getting an easy 25mpg highway, but it was way slower and likely way lighter and definitely more aero. I did get a regular 23mpg with the Skylark with a low compression/small cam combination. It could simply be the cam, but I don't want to admit that, so that being said, I'd like to see what JW does!
With the current engine, I got a best of 16 with a Q-jet (non-optimized) and 19 (repeatable) with the EFI. With the old low compression engine with small cam it was 23 (repeatable) with a Q-jet (it also had narrower tires). The low compression engine only makes around 300-320HP, so waaay docile.
docile yes....but 300 would still be enough to have fun. Anything getting over 17 MPG (what my Xterra gets now) is cool by be for driving cross country. Starting to like the idea of using my spare 455 with low compression heads or even a 401 for an experiment in fuel injection. added bonus.... not being that guy with the LT1
300-320HP, 3.23 gears, open diff, exhaust piped down to a single 2" glass pack, and 23mpg highway, 16 around town and yes, still plenty of torquey fun! http://www.youtube.com/watch?v=R_CCLSwdLhU There is a slight break in the rubber for shifting to 2nd gear =D
Ya' don't say!?!? (Re: Dumbed down MPFI talk) Howdy Paul and V-8 Buick members, Is that so? . . . . Golly, I wonder which Buick wagon it is going to end up in . . . . . . :Brow: Cheers, Edouard :beer
