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#1
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Timing Map for 428 EFI
I have been kicking around the idea of adding EFI to my 65 GTO with a 69 428. In preparation I have been doing a lot of reading which includes the installation manual to see if I have the basic knowledge (or lack thereof) to be able to do this and have an end result better than what I currently have. One thing I noticed in the instructions, if the EFI ECU is going to control the timing, they want you to enter a timing map for your engine for the cranking, idle, cruise, and WOT timing. So, I am going to ask the experts on here what I should use for these values. Here are the specs for my engine and the current timing. The unit I am looking at is the Holley Sniper 4150, 550-511.
The ignition is a Mallory 6AL with a Mallory Pro Master Coil, and Mallory Unilite Distributor. If I do this the distributor will be replaced with a magnetic pickup unit so the EFI can control the timing. I am using ported vacuum advance but that will be disconnected with the EFI. This is the current timing curve; idle 12, 1000 15, 1500 22, 2000 32, 2500 36. The mechanical timing is 24 degrees. Recently I had the engine and carburetor tuned a little better and he increased the idle timing to 15 degrees which gives me a total of 39 degrees. The engine is a 1969 428 out of a Grand Prix and has been bored 40 over which makes it a 435. It has its stock crankshaft and the connecting rods are out of a 421SD. The pistons are RaceTech 5cc flat top pistons and the pushrods are made by Butler Performance. The rockers are 1.65 roller rockers by Harland Sharp. The timing chain is the double roller chain from Butler Performance. The heads are Edelbrock 87cc round port heads that were originally built, ported and polished by Bruce Fulpner of Rock and Roll Engineering and they were reported, in the June 1996 issue of High-Performance Pontiac magazine, to flow 300cfm at .550 lift on the intake. The intake is an Edelbrock RPM that has been ported and polished to match the heads. The block was decked to .001 and the heads were also shaved to give a final compression ratio of 9.85 to 1. The cam shaft is a Lunati VooDoo 60903 (10510703) with an advertised duration of 268/276 and 227/233 at .50 lift and a gross valve lift of 538/554 with the 1.65 rockers. The carburetor is a 1976 800cfm Quadrajet that has been tuned to the engine. I have not had the engine dyno tested yet but DeskTop Dyno estimates it at 476HP and 573ft/lbs. torque with a high flow intake and 509HP and 574ft/lbs. torque with a max flow intake. I will be very happy if this engine falls anywhere within these numbers. The transmission is a 5-speed Tremec TKO600 Street and Strip Transmission with the .64 overdrive. I have the McLeod RST Twin Clutch set up for street use. I was able to use my stock 11” flywheel with this setup. The rear end has 3.36 gears and posi-traction and with the 5-speed at 70MPH in fifth gear the engine only turns 1890RPM. So, what would be good timing numbers to enter in the setup for cranking, idle, cruise and WOT? This is what Holley recommends; cranking is preset to 15, Idle Timing – 18-34, Cruise Timing – 32-48 is typically used when cruising for optimal fuel economy, Wide Open Throttle Timing (WOT) – Older V8 engines are usually between 32-38 degrees. Thanks for the advice, Dale
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1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
#2
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This area tends to get over-thought, especially with these TBI units. What you're providing as the timing map, is essentially the mechanical + advance curve of your standard distributor. If you know your curve currently and your engine likes it, just interpret that data and move it over to the EFI unit.
The only main difference is you have the ability to set a cranking timing setting unlike a mechanical curve where that's basically static depending on where the initial timing is set. Typically you'll set this a little lower to aid in turning the engine over easier. From there, just take your current figures for your initial advance which is your idle timing, total advance which is your WOT timing and the amount of advance you have in your vacuum can which is your cruise timing. The unit's software will interpolate that data and add or remove timing as needed based on rpm and MAP reading.
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-Jason 1969 Pontiac Firebird |
#3
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So you had one of Fulpers porting jobs that in really where just a polish job done to them , he soaked a lot of guys with that ploy, so don't feel bad!
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#4
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Quote:
Dale
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1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
#5
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No worries.
You can of course also run these things without timing control. Because the timing map is pretty basic, unless you need the ability to retard timing for nitrous or boost, there's not a ton to be gained over a well curved mechanical distributor. That said, the Unilite's are pretty noisy and the EFI units don't like them all that much. I certainly had issues with mine on my FiTech. Given that, if you're going to go the sniper route, I'd get a new distributor and at that point you might as well utilize the timing control.
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-Jason 1969 Pontiac Firebird |
#6
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Quote:
Dale
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1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
#7
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What is wrong with your Q-jet that is pushing you toward the EFI, or do you just like eye candy?? A properly tuned Q-jet will run just as good as any EFI at a far lower cost/level of complexity in my humble opinion. You wont really get much/any ROI with an EFI system relative to a Q-jet.
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************************************* 1968 Lemans. 37,000 original miles. GTO clone. 462ci/KRE 290 heads. UltraDyne 280/288 Solid/850 Qjet by Cliff/Performer RPM/TSP 9.5" in TH400/8.5" 3.42 gears/3950# Race weight/12.58@106 at Bandimere speedway high altitude |
#8
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Quote:
Dale
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1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
#9
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With the Sniper, the best unit to use on a Pontiac is the FAST dual sync. It does the same thing and should hook right up to the Sniper harness.
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-Jason 1969 Pontiac Firebird |
#10
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Quote:
Dale
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1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
#11
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Later this month I'll have my car at a chassis dyno to dial everything in, though it's running great now. The instant starts are what really impress me. Whether 50 in the garage, or having run for an hour and really heat soaked. I know you can accomplish that with a carb, but I never could. Britt Bettell
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1975 Firebird / 1970 4" stroke 400, 6.800" Rods, 87cc Edelbrocks, XR-288-HR roller cam, Harland Sharp 1.5 roller rockers, Edelbrocks Pro-Flo4 port fuel EFI, Super T-10, 3.73 Posi. |
#12
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Quote:
Dale
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1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
#13
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Your above question largely depends on the current state of tune of your carb and ignition system.
One of these TBI EFI systems isn't going to create more power than a properly dialed in carburetor. The people that claim power increases typically eith had a carb out of tune, incorrect size/type for their application etc. What the EFI excels at over the carb is in driveability and adaptability to different driving conditions. Fitted with a proper modern fuel system, cold and hot start issues as well as vapor lock are decreased if not all together eliminated. Throttle response is improved and fuel delivery during rapid and sustained acceleration is improved. 68lemans462 isn't wrong in his statement, but that statement only applies when you have a properly dialed in carb. The further from dialed in your carb is currently, the more benefit you'll see in the switch. In my personal experience, I went to a FiTech because I was having a terrible time with vapor lock. I had done fuel line heat shielding, wood and phenolic spacers, carb heat shields, new fuel pumps. During the summer I was only able to drive the car for about 20 minutes before it became a reliability issue on my car. I had spent quite a bit of time working on my carb setup and it was probably about as good as I could get it for an e-carb. When I installed the FiTech, I didn't really see a power increase, but not a single time have I dealt with vapor lock since. I went from putting maybe a couple hundred miles on the car a year, to now having put about 8000 on it in the past 2 years. When we purchased my wife's 71 Chevelle, one of the first things we did to it was a FiTech. The difference on that car going from a double pumper holley (out of tune and the improper carb for a heavy automatic car with a mild 350) was dramatic. I'm not in the EFI is always better camp. I'm in the use, what is best for you and how your drive the car camp. For me, that cheapo chinese EFI system was the best money I've ever spent on my car.
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-Jason 1969 Pontiac Firebird |
#14
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Quote:
Dale
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1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
#15
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That's what makes the EFI sweet. It makes calibrations on the fly. I deal with it (with carbs) daily, and it's a fair amount of time spent in tuning to get the carbs happy to deal with the various conditions out here. |
#16
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Quote:
Dale
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1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
#17
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The throttle response throughout is more defined with no lags or bogs. Of course, the starts are nice. The first very first fire-up was immediate (even though I had No. 5 and 7 wires crossed at the cap.) with the intake air temperature reading 58 degrees. After I shut down and fixed that boneheaded mistake, the car fired right back up and I got the idle and timing set correctly. The third start was here: https://youtu.be/L1kNCXROdpU Setup was easy, I answered a few questions and it loaded a base map for the computer to then modify as it learned. The first drive was a little rough, but after about 5 minutes the ECM figured out what was going on and adjusted what it needed to. I drove yesterday for about 30 minutes (80 degrees outside) until the car was good and hot. Stopped for a burger for about 15 minutes, then fired the car right back up. It starts like my 2015 Chevy truck. I didn't do it for power, or mileage. Britt Bettell
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1975 Firebird / 1970 4" stroke 400, 6.800" Rods, 87cc Edelbrocks, XR-288-HR roller cam, Harland Sharp 1.5 roller rockers, Edelbrocks Pro-Flo4 port fuel EFI, Super T-10, 3.73 Posi. |
#18
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The biggest change to the power seems to me is from the fact that the qjet had that lag time when the secondaries opened and the power came on more gradual. The Holley fuel delivery is pretty immediate. Just a different feel altogether. I don't really think it has any more power.
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Robert 69 Firebird-462/Edel round ports/currently running the Holley Sniper/4sp/3.23posi/Deluxe Int/pwr st/vintage air/4wl disc( a work in progress-always ) http://youtu.be/eaWBd3M9MN4 |
#19
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Quote:
Dale
__________________
1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
#20
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Quote:
Dale
__________________
1969 428 Tremec 5 Speed U.S. Army Retired Retired Helicopter Pilot |
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