I've got a good 455 with mildly ported iron Stage1 heads, TA212 cam, 9.5 compression, TA shorty headers in a big ol' heavy LeSabre. My goal is low-buck efi on a reasonably-stock-appearing 455 (at least with the aircleaner on), which means Throttle-Body Injection (no injectors-in-the-intake, sorry). After looking into them for awhile, considering tune-ability, budget and learning curve, I narrowed my search down to either the older Holley Projection 4Di, or the newer Commander 950 systems. I recently got a deal on a Holley Pro-Jection 4Di setup complete with a 2-fuel-tank kit (switch, valve, extra fuel pump), knock sensor wiring ( but no sensor or module), a new closed-loop kit (narrow-band O2 sensor), a calibration module, and the mapping software. Couple of questions before I start bolting things on, though... The throttle-body is rated at 700 cfm, not the 900 cfm one I was hoping for. I'm guessing that's going to be small, but was wondering if carb-vs-tbi made a difference on the engine's cfm wants, since theres no need for a carb vacuum signal. If its too small, at wot and high rpm the MAP would be significantly below ambient, correct? How far below is too far? And is it's too small what are the options for increasing the cfm? How complicated (expensive) is it to get bored w/ larger throttle plates? The injectors that are in it are the old-style Holley 45pph ones (I think, they have no part numbers but have blue tops). I calculate they'll only support 350hp max at the max fuel pressure (20psi). From a couple of runs on a 1/8-mile track, Im guessing the engine makes 400-420 fwhp. How do you tell if the injectors are too small? I havent seen many of that style injector on ebay recently, so apart from dropping $150 on the upgrade kit and then another $150-200 on 4 bigger injectors, are there any other options? Anybody got some theyd part with? As a side note, I found that the Ch*vy 454 TBIs were 2-bbl units rated at 675 or so cfm, and used 80-85pph injectors, which would be smaller than this Pro-Jection TB. Did they only make 300 or so hp, or is there something Im missing? Also, what about using a GM 454 throttle body with bigger injectors? If Im going to have to bore out a throttle bodyand the injectors would be much more readily available seemingly. I dont know options, options, options Fuel delivery: Im planning on using both electric fuel pumps, one back at the tank and the other up by the engine. I cant decide if I want to leave the Stage1 mechanical pump in place (with or without its pump arm) and run the pressurized fuel through it and the stock fuel line with a short extension to get to the back of the throttle-body so keep the stock look, or just remove it and run the fuel lines up the back of the engine for a cleaner look. Anybody have any opinions? Also, is the stock fuel return line (a/c car) large enough? If this setup would work right off the bat or with a minimum of fuss/expense, thatd be great. If not, then Ill be ebaying this stuff and watching out for another deal.
I used the previous version of the Projection from 1993 to 2000. Liked it a lot. Now I use a port FI system, but the Projection was definitely great in the bang-for-the-buck category. -Bob C.
I'd seen your comments on Projection systems before, and I was hoping you'd chime in on this thread. Got any suggestions or pointers?
The system I had was the 900 CFM system. At the time, that was the only one available. Back to that in a minute. It sounds like fuel delivery will be a problem for you. On my 455 currently, I have 36# injectors. 36 times 8 is 288 #/hr. If you only have 4 x 45# injectors, that's only 180 #/hr total, and in my book that's not good enough for a big block. Based on this point alone, I'd put it on ebay and start looking for something else. The best time I ever got on my Projection was a 13.38. My first run on my new system was a 12.79. When I looked into it more, I realized that I was never getting enough fuel with the Projection. However, I don't think that was because of injector size (I think that had 4 x 86# inejctors), but I realized it was due to a lack of fuel pump! The fuel pump that came with the system was inadequate to keep up with the system. On paper it all worked, but over time the delivery decreased and I was apparently running lean. If you want to go to FI, I'll recommend one of those new "fuel injection" tanks from Spectra (for a variety of reasons). If you don't do it up front, you'll wish you'd done it in a few years. To this day, I actually have *two* fuel pumps (both external)- the second one comes on a full throttle. You'll probably have to do the same thing sooner or later if you don't get a proper gas tank with an internal pump. Thoughts so far? -Bob C.
Well, I tore the throttle body down for cleaning and inspection, and it looks like there's room for improvement, like blending that ridge above each bore back into a smooth curve - although I'm sure I don't want to go very far down into the throttle bore area. And from info I gathered online, you can raise the injector pod 1/4" with a gasket/spacer and gain airflow through the TB. Yes, the 45# injectors are way too small. I've found a couple of 75#, and a whole bunch of 85# ones on ebay. I was wondering about the idle quality with the 85# ones, but if they worked for you then that answers that. On fuel delivery, seems to be two issues to deal with: Fuel sloshing/starvation and adequate pressure. I'm not sure sloshing/starvation will be an issue, since I don't do *that* much hard cornering or launching (well, in my mind I don't :laugh: ) To ensure adequate pressure, I was planning on using both pumps, one at each end of the car. If you think that would be inadequate, how about using a surge tank (I'd call it an accumulator) up at the front of the car, fed by either one of the Holley elec. pumps, or the Stage 1 mech. pump? Good description of the idea here; http://www.sdsefi.com/techsurge.htm , could maybe use something like this 1 gallon fuel cell - or here's an interesting approach using a large fuel filter: http://madscientistmatt.blogspot.com/2005/12/surge-overkill.html Then I could use either the Holley pump or a higher-pressure one right close to the TBI. Hmmm...the more I sit here and think about it, the more I like the "fuel filter as a surge tank / accumulator", except I'd put 3 taps into the top of the filter housing and plumb them as in the sdsefi diagram. Use the existing high-volume mechanical pump to feed into the filter, and an electric pump from the filter/accumulator to the TBI. Or get rid of the mechanical pump and have one electric back at the tank in its place. Having a huge filter in there can't hurt anything either. At any rate, I'm planning on using a fuel pressure gauge while tuning to ensure I've got pressure. (I've got a good small liquid-filled one I'm planning on tying to the back of the hood temporarily so i can check it at wot) I googled Spectre, efi, and fuel tanks, but didn't come up with anything related to an old Buick. Are they making drop-in Buick fuel tanks with inboard pumps?
I'm driving an '87 Buick Regal with a 455 Buick Stage 1 engine. It has a 900 cfm Holley Projection throttle body and a Megasquirt digital fuel controller. The throttle body has four 85 lb/hr injectors at 15 psi fuel pressure. I originally used the Holley analog controller with six knobs to adjust performance but it failed and left me stranded. Since analog controllers are no longer available, I switched to a Megasquirt digital controller that was assembled from a kit. My Regal ran its best time of 12.8 sec at Norwalk with the Holley throttle body. With fuel injection, the engine starts well, idles smoothly and has crisp throttle response. I am disappointed that I haven't noticed much improvement in fuel mileage, especially since it uses an oxygen sensor. Sensors include: narrow band oxygen sensor, throttle position, intake air temp, water temp, and RPM. A laptop PC is used to adjust the digital controller and to view all input and output signals while driving. Hal <wahlehw@att.net>
Just asking you guys with pro-injection....what distributor did you use for the computer to control the timing....? A 455 hei converted to a 7 pin module....?
Spectra's web site is: http://www.spectrapremium.com/spectra.html Select E-Catalogue in one of the tabs near the top and it should take you to: http://ecat.spectrapremium.com Along the left had side go down to the "Part Number" entry and in the drop down box under "Product Line" chose "Classic Inj.Fuel Tank" then enter GM34QFI in the next line. This is the part number for the 1970 GS tank. The problem is they think a GS and a Cutlass take the same tank. On mine the vendor Tamaraz had to send me a Buick filler neck to swap out. Yes googling for this information does not yield much . . This tank has the baffle at the bottom to keep fuel around the pump for those hard launches. A standard tank will not have the baffles and the car will nose over on hard launches, due to loss of fuel pressure. The supplied fuel pump is rated for 50 to 60 gph which should be adequate to keep up with a 500 hp engine at 85 psi. Your regulator then keeps the fuel rail pressure at a constant 43 psi. This is the reliable way to handle the fueling. I used the stock 3/8 inch fuel line with new sections of woven stainless steel coated rubber lines at the back where I added an EFI fuel filter, under the drivers door where the back fuel line meets the front fuel line and at the transition from the front chassis fuel line to the engine fuel line. The stock 1/4 inch fuel return line was adequate with new sections of flexible EFI line replacing all the older rubber sections. Hope that helps
Thanks for the info, but I've got a LeSabre with a 25-gallon fuel tank, and will be running a TBI (lower) pressure system, like 13-20 psi. Spectre shows only a stock replacement tank for big Buicks, sigh... Good info on the fuel and return lines, Thanks! :beers2:
