EFI for m110 TPI vs TBI

[Cephallus]

Any opinions on whether I'd see a dramatic performance improvement going with TPI (using the 280E manifold/head on my donor engine) vs retrofitting a TBI setup onto my existing carb manifold? I was thinking of something like this GM unit. I'm building a Megasquirt ECU and was am planning to use Ford EDNIS and an MSD box to control ignition.

It seems that the TBI setup would be the simplest and most-straight forward for the car...I'm a little leary of cutting/welding to accomodate the larger manifold on this project. Everything is already there - TPS, FPR, everything. With a TPI setup, I'd be looking at having to fab a fuel rail and setting up a TB with a TPS, adding a separate FPR, etc. Fun is fun, but I'm a little short on spare time these days, and I'd like to actually finish one of these projects...

Thoughts?

[Hit Man X]

If you're going through the work of building and tuning the MS (I am too on the running BMW) run direct port EFI. MS uses only bank to bank EFI so you know.

There is a reason TBI was gone after about '95 with GM, it's just a glorified carb.

Ask yourself what you're trying to achieve, just the ability to start and drive easily? Go with TBI. After for more performance, go with multi port.

[JMURiz]

If you went TBI, could one of those after-market kits from edelbrock etc work? I think it comes with an ecu etc, maybe they have one for a jeep inline 6...not sure if the firing order is the same though...just ideas.

[Cephallus]

I'm going with the Megasquirt unit for 2 main reasons: 1) Cost. It's much less expensive than comparable off-the-shelf solutions and 2) Hack value. Laptop tunability, multiple maps, fine-tuning of fuel/spark, etc.

[Tomguy]

Originally Posted by Cephallus

2) Hack value. Laptop tunability, multiple maps, fine-tuning of fuel/spark, etc.

That won't mean crap with TBI. As said, TBI is a glorified carb. You don't want TBI on your MS setup if you want to get the most performance and efficiency. All that customizable tuning would be for naught.

[Mike D]

The real beauty of the Megasquirt is that it is a complete ECU. It can be programmed for TBI or multi-port injection. You can pull the ECU off a 4 cylinder TBI set-up and drop it onto a monstrous V-8 application and simply re-program it.

Firing order makes no difference to it. It is not application specific. It works either on MAP or MAF. (manifold air pressure or mass air flow).

I'm converting my '73 280 to TBI. I've got all the hardware I just need to build me a surge box and find the time. I figure I'll have the time in about March, either '07, 08 or ........

[Cephallus]

Mike - what throttle body are you using?

Tom - considering that the MS ECU doesn't handle sequential injection, is there a significant enough performance loss to warrant the extra setup work involved in converting this engine to port injection? Carbs are not necessarily a bad thing - they're just difficult to tune...having to take apart the carb to change out jets is significantly more labor intensive than changing a couple of parameters in your fuel map and uploading it to the ECU. True, the function of the injectors over the throttle plates is similar to a carb, but the adjustability of the fuel map in realtime is the real advantage here, no?

My goals are:

1) Reliable cold starts
2) Smooth idle at all op temps
3) Best balance of efficiency/performance for the engine

I'm not really looking to pull every possible fraction of HP from the engine...if I were, I'd be doing a much more comprehensive build-up than simply refurbishing the head and dropping an open-source ECU on. I do have euro cams on the way, and am re-plumbing for less-restrictive exhaust.

[Mike D]

I'm using a TBI unit from a 90's Astrovan 2.5L. I already have an adapter plate for the 2BBL carb I am running instead of the Solex.

I'd rather increase the pulse rate than shorten it i.e, adjusting the short milliseconds burst to fire a tad longer to compensate for the 2.8L 6 cylinder as opposed to shortening it for a lesser fuel requirements of the larger engines. The fewer "opens and shuts" the better for an electronic device.

I'm using a "surge" tank mounted up front for three reasons. I can use a standard Bosch in-tank pump, (available for $50 at any Autozoo), ease of wiring and I don't trust the old supply line on my 34 year old car for the rigors of 3 bar (45 psi) pressure. I am using the existing return line because of the heat issues involved with the short line length. The surge tank will be supplied by the existing electric fuel pump.

I'm still figuring out an "engine running" switch for a fail-safe on the pump. It'll probably involve something from the distributor side of the coil.