[gtobird]

Folks,

Let me first start out with PLEASE DON'T SHOOT ME FOR MY IGNORANCE AND WILLINGNESS TO SUGGEST SOMETHING VULGAR TO PURISTS OF THE PONTIAC FAITH. My problem is that my heart drifted with the purchase of my 02 TA when I bought it off the show room floor. I still have two 100% Pontiac 1968 engines in my fold. Okay, now that I have that out of the way, I keep wondering why a Multi-Port fuel injection system couldn't be modified for use on a true Pontiac engine. Had GM kept on building true Pontiac engines, without question Pontiac engines would have ended up with fuel injection as the norm.

When I look at an LS1 engine, the main differences between it and an old school Pontiac engine are:

1.) Firing Order
2.) MAF and Injectors mated to intake vs carburetor and matching intake
3.) ECM Control on the LS1 for injectors, and distributorless ignition
4.) High Pressure electric fuel system vs low pressure mechanical
5.) Use of reluctor for ECM on the LS1
6.) Different stroke / bore sizes
7.) Other things I am missing (Besides the fact that the LS1 is aluminum)?

So, let me address these one at a time in wanting to morph an LS1 fuel injection system onto a Pontiac engine. I'm assuming I can use stock LS1 components such as, sensors, ECM, injectors, fuel rails, MAF and modified reluctor with custom fabricated intake.

1.) I believe the firing order difference to be no big deal. You could re-route the ECM wiring to coils and injectors so it tricks the ECM into believing the firing order is that of an LS1. In other words, the Pontiac firing order of 18436572 looks like an LS1 18726543 firing order by routing the coil and fuel injection wires as follows:

#7 LS1 wire now goes to #4 Pontiac
#2 LS1 wire now goes to #3 Pontiac
#4 LS1 wire now goes to #7 Pontiac
#3 LS1 wire now toes to #2 Pontiac

The other cylinders have the same place in the firing order already

2.) MAF and injectors would simply be LS1 parts used on a Pontiac engine. There were different size injectors used over the years. I'm guessing you would have to find a Pontiac cam (or custom grind one) that would match the profile of an LS1 cam for a given set of LS1 heads that come close to the heads being used on a Pontiac engine.

3.) Since the conversion would be done with an LS1 type ecm, the distributor would no longer be used, but a dummy distributor bottom half would still need to be used in order to drive the oil pump. Again, I don't see this as a big deal.

4.) Yes, a high pressure fuel system would need to be used, but there are all sorts of aftermarket fuel pumps available, both in tank and out of tank. It's the same issue LS1 swappers deal with all them when dropping one into a vintage vehicle

5.) I would have to believe retrofitting a reluctor and sensor on a pontiac engine is doable. I haven't looked at how it would be done, but it seems like it's either a matter of boring a hole in the back of the engine block for the sensor or creating the same type of mount on the trans case / bellhousing. I'm thinking possibly also could be done with a custom inspection plate for the sensor.

6.) I'm not at all clear on how different bore / stroke combinations would be dealt with, but since there are so many different LS engine combinations and hot rodders that are building different combinations, I have to believe there are tuners out there that could accomodate a cutom build with a tune to the ECM

7.) Okay, so what else am I missing? Yes, the intake would have to be a complete custom and an oxygen sensor would have to be added to the exhaust. I'm thinking the most difficult part in all of this is the intake, but hey, there are plenty of 3D printers and skilled metal fabricators out there.

So, besides the fact that this would be bastardizing a Pontiac engine, is this a totally ridiculous idea, or could it be made to work and provide the reliability of other modern engines? I already know that this concept will be pummeled by Pontiac purists and those that only want carburetion. As for the cost vs benefit case? It could be totally ridiculous, then again?????????

Forgive me, for I know not what I am a suggesting..........

[grivera]

I can’t help other than to recommend this be moved to the EFI Forum for better exposure: http://forums.maxperformanceinc.com/...play.php?f=570

[hgerhardt]

It's a great idea and many of us have already done it and reported about it here! I suggest you spend some quality time in the archives of this forum. I remember at least one guy adapted a GM ECU to run a Pontiac, and I think it was an early LS one.

I've had multi-point sequential EFI on my '66 GTO since 1998 and would never go back to a carb.

For a Pontiac retrofit, I really don't see the value in sequential EFI... batch-fire would be just fine and if I was doing this again, that's what I would do. There's no way any of us has the patience, dyno time nor $$ to accurately set up sequential injector timing throughout the engine's range. But if you have your heart set on an LS ECU, then of course you'll have to come up with a way to measure the camshaft TDC for the sequential part. I did it by modifying a small-cap HEI from a TBI SBC truck engine.

[Scarebird]

Why reinvent the wheel?

https://www.summitracing.com/parts/e...0/make/pontiac

Were I to do it again I would route the fuel inlet front driver's side if reusing the hard line, Passenger front if using new (Chevelle routing).

[HWYSTR455]

Originally Posted by hgerhardt

It's a great idea and many of us have already done it and reported about it here! I suggest you spend some quality time in the archives of this forum. I remember at least one guy adapted a GM ECU to run a Pontiac, and I think it was an early LS one.

I've had multi-point sequential EFI on my '66 GTO since 1998 and would never go back to a carb.

For a Pontiac retrofit, I really don't see the value in sequential EFI... batch-fire would be just fine and if I was doing this again, that's what I would do. There's no way any of us has the patience, dyno time nor $$ to accurately set up sequential injector timing throughout the engine's range. But if you have your heart set on an LS ECU, then of course you'll have to come up with a way to measure the camshaft TDC for the sequential part. I did it by modifying a small-cap HEI from a TBI SBC truck engine.

Remember your car well, and it's inspiration!

I too did a EFI setup in 98/99 and did the 99 East Coast Power Tour with it. Based on an ACCEL DFI v6 ECU, it was batch, since there was no off the shelf cam signal available for Pontiacs, so mine went batch.

My new setup is SEFI though, Dominator EFI based. (Check my build thread)

.

[gtobird]

Originally Posted by hgerhardt

It's a great idea and many of us have already done it and reported about it here! I suggest you spend some quality time in the archives of this forum. I remember at least one guy adapted a GM ECU to run a Pontiac, and I think it was an early LS one.

I've had multi-point sequential EFI on my '66 GTO since 1998 and would never go back to a carb.

For a Pontiac retrofit, I really don't see the value in sequential EFI... batch-fire would be just fine and if I was doing this again, that's what I would do. There's no way any of us has the patience, dyno time nor $$ to accurately set up sequential injector timing throughout the engine's range. But if you have your heart set on an LS ECU, then of course you'll have to come up with a way to measure the camshaft TDC for the sequential part. I did it by modifying a small-cap HEI from a TBI SBC truck engine.

That's the kind of inventiveness I was hoping to see. How is it for reliability, performance and gas mileage compared to carburetion?

[JLMounce]

Lots of options for port injection. And yes you can put a GM 24x system on these. It’s definitely been done. In fact I think there’s a kit out there.

Scott65 has some great write ups on his megasquirt system as well.

[gtobird]

Okay, so let me now go to the endgame. Some type of stack intake system is where my dreams are.

https://reduxracing.com/products/ind...en3-ls-engines

It looks old school bitchin while being new school!

[hgerhardt]

Originally Posted by gtobird

That's the kind of inventiveness I was hoping to see. How is it for reliability, performance and gas mileage compared to carburetion?

Mileage improved 10% (from 10 to 11 mpg), but the biggest improvement is the drivability. Hot or cold, A/C on or PS pump at full lock, in Drive or neutral, none of that matters thanks to the idle air motor. With a big street cam, any of the above messes with the precarious balance of idle settings on a carb, and that just all goes away with EFI. Plus I can park the car for 4 months and it will start like it was last run yesterday.

Performance-wise it's about a 10th quicker in the 1/4 than the best carb setup I ever had (on a Street Dominator), and I spent a lot of time tuning that before the EFI. Most of that 1/10th is probably due to my home-made manifold rather than EFI though.

Another cool thing is N2O. There's a nozzle in the intake duct upstream of the throttlebody and the ECU increases pulsewidth and retards timing while spraying. Really nice to tune that way, although you'll need an aftermarket ECU to do that.

[hgerhardt]

Originally Posted by HWYSTR455

..................My new setup is SEFI though, Dominator EFI based. (Check my build thread)

.

I did check it out...nice!

One thing mine does not do is look stock. However, it's good entertainment to stand 6' from the car at a show and watch the people do double-takes and try to figure out what's going on there.

[Sirrotica]

Originally Posted by gtobird

Okay, so let me now go to the endgame. Some type of stack intake system is where my dreams are.

https://reduxracing.com/products/ind...en3-ls-engines

It looks old school bitchin while being new school!

Speedmaster makes 8 stack electronic fuel injection setups, but of course not for a Pontiac Stratostreak engine. You'd have to butcher up one for a more popular engine, and adapt it to the Pontiac. I have the same dream of having an electronic 8 stack system on a Pontiac Stratostreak V8.

There are some conversion companies that will convert a Hilborn, or Enderle, etc. systems, but the price tag is between 4-$6000, plus whatever you have to pay for a core for them to convert, if you can find one to buy, Pontiac 8 stack systems are fairly rare.

[Formulajones]

Agree with scarebird. No need to reinvent the wheel, EFI stuff has quickly evolved. No need to piece meal a home made setup anymore, this stuff is already out there to be had.
Personally I would prefer a Holley based dominator system.

[MarkS57]

Originally Posted by Scarebird

Why reinvent the wheel?

https://www.summitracing.com/parts/e...0/make/pontiac

Were I to do it again I would route the fuel inlet front driver's side if reusing the hard line, Passenger front if using new (Chevelle routing).

I've looked at this myself. One thing I like about this system is the ability to mount the ECM in the passenger's compartment, away from engine heat. Just gotta come up with the scratch to buy it.

[Formulajones]

The only issue with the Edlebrock system, and this has been talked about before, is coming with canned tunes and their somewhat limited ability for in depth tuning. I'm sure it would work fine in mild to near stock applications but might become more of an issue on anything more rambunctious. In fact there was a member here that tried one on a more radical Pontiac and ended up taking the system back off after going round and round with Edelbrock, having them change things in the tune back and forth and still never made the engine completely happy. In the end he switched to a Dominator system.

I personally don't care for the tuning "app" required and using blue tooth to connect to it. Just give me a USB cable and a laptop.

[R 70 Judge]

Holley Terminator X seems to be a very popular option for switching to EFI. You can obtain the crank signal and cam signal easily by using their dual-sync distributor.

[Marv]

I did custom 2x4 EFI on my 389 for my '64 Bonneville build.



The throttle bodies were a pair of air-only 4bbl FAST units mounted on an Edelbrock 2x4 manifold I had drilled and LS3 injector mounts welded on. Same guy made my fuel rails, which I tapped for -6 ORB fittings. I did a custom fuel tank with a G8 GXP MRA fuel pump assembly, with -6 fuel line in a deadhead set-up so it was nice and clean.



I used a generic Holley 58-tooth reluctor wheel which I bolted to my harmonic balancer and ran a generic cherry sensor for a cam sync. The distributor was deleted and I bought an oil pump plug from BOP engineering, so I could use LS1 coilpacks. I also blocked off the mechanical fuel pump port on the timing cover.




I bought a late-model style water temp sensor and ran that, while the FAST throttle bodies used GM-style intake air temp sensor and stepper motor-driven idle controllers. The Haltech Elite 750 ECU I had couldn't drive the stepper motors for idle control so I set up a Bosch 2-wire idle controller and blanked off the IACV ports on the FAST throttle bodies.



It ran great but I - frankly - got some bad advice on the engine specs and later sold it off and replaced it with a forged, stroked and supercharged iron LS.

[flat-bill]

Why not use the SM intake with the injector bungs and use a Megasquirt??

[Red Box Rebel]

I converted to Edelbrock ProFlo4 Two years ago. It works great and Fuel economy improved from 12 to 15 MPG. Not sure why fabricating your own system from a hodge-podge of parts is more desirable than a direct bolt-on replacement for a carburetor from Edelbrock. Edelbrock still uses a distributor, but the ignition curve is fully computer controlled. How much better is a distributor-less ignition system than a computer-controlled distributor?

[Marv]

The way I see it piecing your own EFI system together allows you to spec your system out to your needs, lets you pick the ECU you want to run (or have prior experience tuning), and going distributor-less let's you run sequential ignition timing for much better ignition control - this isn't needed but let's you get the tune dialled in far better than adapting to a dizzy.

The car would still run with a bolt on system, but in my experience those bolt on kits are only 80% sorted and generally benefit with a lot more custom tuning to suit the specific motor. If you have a high compression engine or want to run flex fuel or do other things like that, then setting up a proper standalone ECU and piecing your control package together yourself is the way to go, IMO.

[Scarebird]

Originally Posted by Marv

...and going distributor-less let's you run sequential ignition timing for much better ignition control - this isn't needed but let's you get the tune dialled in far better than adapting to a dizzy.

The Eddy system IS sequential.

Originally Posted by Marv

...then setting up a proper standalone ECU and piecing your control package together yourself is the way to go, IMO.

There is a much steeper learning curve here; the Pro-Flo setup is close to plug-n-play.