EFI straight eight Buick

[GH]

Mike Collison and myself is changing the #1950 Buick to EFI instead of carbeurated. We had installed the MegaSquirt ECU last year for datalogging only. We will retain the carb and use it as a throttle body, we will have an injector in each of the intake ports and 2 injectors above the new 6-71 blower. Have new Venolia flat top blower pistons, will have the block "O" ringed with stainless steel wire and having a cam ground for the blower. Also modifing the block for a full flow oil filter system.

[SPARKY]

pictures--- man ----pictures

[RichFox]

I know the 4bbl will work as an air valve, but it seems to me that with all the throttle bodies laying around junk yards these days. And the clean unobstructed flow through them that It might be worthwile to use one. I have a number of 65mm throttle bodies I have no real use for and one brand new 90mm throttle body that is worth around $25 and shipping to me.

[GH]

Sparky, don't know how to do photos, sorry, I mean I am real sorry. Rich, Mike wants to keep the old look by using the carb as the throttle body. I think in the future he will go to turbo charged with efi, but for now he wants it this way.

[SPARKY]

Gary----that is not an acceptable excuse- -----you could give us all a nice Christmas present  :lol:by learning to post picts.---you are just working on too much neat stuff!!!!!!!!!! and we all knoiw how we feel about STUFF---lol

[Sumner]

Sparky, don't know how to do photos, sorry, I mean I am real sorry. Rich, Mike wants to keep the old look by using the carb as the throttle body. I think in the future he will go to turbo charged with efi, but for now he wants it this way.

I've seen late model electric Q-Jets used as a throttle body and they have a TPS built into them.  I think they machine off the air horn on top and all of the choke stuff.  I don't know what they do about the secondaries as they are vacuum and not mechanical.  I saw this some time ago, but  didn't follow up as like Rich said just get a throttle body if you don't care about the look,

Sum

[Milwaukee Midget]

What is the port configuration on the straight 8?  It's been years since I've seen one.

[GH]

The intake ports (4), each one feed 2 cylinders, very poor design. Sum, we already have the TPS on the carb, no choke and mechanical secondaries. We are going with 55 pph injectors in the ports and 95 pph injectors above the blower.

[Milwaukee Midget]

So are the 2-3, 4-5, and 6-7 exhaust ports siamesed, too?

[panic]

1-2-2-2-1

[Milwaukee Midget]

1-2-2-2-1

Thanks, Panic.
Wish I had something that technologically advanced to start with!

[GH]

Each cylinder has its own exhaust port. Unlike the Chevrolet & GMC 6 bangers which have a total of 4 ports.

[4sfed]

The intake ports (4), each one feed 2 cylinders, very poor design. Sum, we already have the TPS on the carb, no choke and mechanical secondaries. We are going with 55 pph injectors in the ports and 95 pph injectors above the blower.

Will you use 8 port injectors or 4?  Problem with shared intake runners is the valve timing. . . . for example . . . cylinder one intake opens, then 180° later cylinder two intake opens, then 540° later cylinder 2 opens.  You must inject only on the open valve.  Otherwise cylinder one will run rich and cylinder two will run lean.  I'm using a 1-6-2-5-8-3-7-4 firing order.

I'm not sure I'm explaining the concept well, but imagine a constant flow injection system as an extreme example.  #2 intake opens 180° after #1 intake opens . . . there will still be some flow into #1 as #2 begins opening.  After #1 is fully closed, all the fuel flows into #2 until it closes . . . then it begins to puddle behind the closed valves.  When #1 opens, that puddle dumps into #1 along with the fuel from the injector while the valve is open.  Since cylinder #2 starts to open while #1 is still partially open, there is no puddle of fuel . . . so cylinder #2 receives less than half as much fuel as #1.

Assuming a redline of 6000 rpm, you'll have about 4 msec to inject your fuel but will require sequential injection . . . not currently available on the MegaSquirt.  There is a router board under development for the MegaSquirt II that may become available next year.

http://www.megamanual.com/ms2/

Jim

[dieselgeek]

You must inject only on the open valve. 

Sorry, but that's not true at all.  There's no such thing as any port EFI system injecting only when the valve is open.  Think about it, an intake valve is open *at most* during 25 % of the combustion cycle, meanwhile at WOT most EFI injectors are running 80-100% duty cycle at WOT.  3/4 of the time an injector is open, the intake valve is closed and on OEM applications, it's even worse than that (conservative cams for torque and emissions).

Emissions at idle and warmup are really the only reason sequential EFI exists...  if what you are saying is true, then how would a batch fire system work on *any* port injected engine?  or TBI injection?   that's how EFI cars were run for a decade until emissions laws began dictating "warmup" emissions be improved, and that is where sequential EFI shines - at lowest duty cycles, during idle warmup.

-scott

[Stan Back]

GH --

Are the exhaust ports separated, but siamesed in the stock exhaust manifold (looks like it in the picture Panic posted)?

Stan