3500 into MGB, ecm & fuel pump recommendations

[3.5MGB]

I'm putting a 3.5l from a 2004 Malibu into an MGB backed by a GM T5 and using the stock 3.9 gear that's in the car now. The engine that came out was driven by a distributor and a Weber so there is nothing to salvage.

I've been reading the forums and can see all the 'discussions' about aftermarket, ODB (1, 1.5, 2) but they all mostly talk about swapping one efi engine into a car that already has an ecm and how to tune it a bit differently. I'm starting from scratch and am interested in what would make the most sense considering that this engine is NA but the next one will be SC'd (and if I can I'd rather not have to swap out and rewire the ecm).

I'd like to be able to swap tunes based on what fuel I'm running 87, 93 or 104 and where I'm running.

I'm not especially worried about trying to keep some random emissions tester happy as the car is to old to need to go in for a test and it'll spend what few hours a year split between a track and tooling down back roads. (No I don't want to spew noxious fumes but I don't need to artificially choke the engine just to get a sticker)

Since the car never had EFI it never had a high pressure fuel system so I need to build that into the system too (again I'd rather not have to replace all of this with the next engine). I'm planning on putting in a fuel cell so I have a blank slate with that too.

I'd like some pointers to threads or to new discussion on these two topics.

Thanks

ps oh yeah I'm putting monster Wilwood brakes and F1 rubber under it all to make it stop too

[bszopi]

What's your budget like? There are alot of options out there, but it mainly depends on your budget. No matter what, with your setup, I would go with an aftermarket ECM. On the budget side, there is the Megasquirt. On the higher end, there are units from F.A.S.T., Haltech, and Perfect Power just to name a few. There are several people on here running the Megasquirts, so you'll have some help with the programming.

As far as the fuel system goes, I think basically get a Summit or Jegs catalog, and just put together a complete fuel system that will work with EFI.

[sharkey]

thewre a quite a few externaly mounted aftermarket efi pumps out there that will support 500-1000hp. areomotive makes a couple, also mallory has one.

as far as computers, depends on what you have to spend. you can grab a wiring harness and ecu from an 89-91 cavalier 2.8/3.1, make the harness work for your car, tune the ecm with a chip burner. id steer clear of that though, in the end its more of a headache. megasquirt is a good system for the money, starting as low as $150 for an unassembled ecu. you can grab the latest megasquirt 2 already assembled for around $400, get the universal harness for $60 and your good to go. the megasquirt is a unique system, as its open source code (always being updated and developed), and even user based code (megasquirt extra) that adds in fetures like boost control, nitrous control, overboost protection, and some other good fetures. its also user based support through the msefi forums. despite what many people say about this system, its been very reliable in my daily driver for almost a year and 20k km now.

[Joseph Upson]

You will only need high pressure fuel hose from the pump to the engine, since it will be an external pump that will not be a problem because you can use metal brake line and high pressure fuel hose together.

As for the ECM, I personally would never go aftermarket when the tested, tried and proven original equipment options are the closest thing to a near full tune for a start, especially if you start with an ecm for the 3400 and proper tuning software which many often don't.

The 730 ecm is an excellent choice, it's cheap, can work without a MAF sensor and since you are starting from scratch you can build your harness one sensor at a time.

Some stock ecm's have been hacked so well there is no real benefit to going with an aftermarket computer unless it comes with a perfect tune for your engine out of the box or offers some very special function the stockers do not in my opinion.

To my knowledge no aftermarket computer comes with the number of parameters and fail safes that the stock computers come with. They simplify things in some ways but not to the point where I would be willing to take that route again. Now if you are talking about the kind of equipment used in F1 racing, well in that case you should be driving one of those cars.

Sounds like it'll be a real go getter, like putting a saddle on an engine.

[85_Olds_Ciera]

I'm putting a 3.5l from a 2004 Malibu into an MGB backed by a GM T5 and using the stock 3.9 gear that's in the car now.

Don't re-invent the wheel:

Welcome to British Car Conversions

[IsaacHayes]

You'll need the 7x external crank trigger sold here unless your ECM can read a 54x or whatever is in the 3500.

[3.5MGB]

Don't re-invent the wheel:

Welcome to British Car Conversions

Yes I've been there and bought a few parts, mechanical so far (excellent quality too!), but I'd still like to hear from people that didn't go that route or that did and what they discovered. Thanks for the reminder anyway :-) I believe I did mention I've been reading so I guess I'm after more advice from people who have actually done something like this, a complete conversion of old school to ecm.

Even if I ignore Dann's advice (which would be odd as I am buying stuff from him) I would like to hear feedback. I'm also planning on taking this car where his average buyer doesn't go 5-6#/hp.

I also still need to come up with a fuel system that will pass SCCA muster.

BTW Thanks for the tips so far!! Hopefully the subject line makes it easier for someone else to find this information next time around.

[Scott_68B]

I think we're looking for different things from our conversions so I'm not sure how useful this will be for you but I have successfully added FI to my B. I decided to go with a GM OBD1 system and I'm very happy with the decision. I seriously considered a Megasquirt but at the time it didn't support GM DIS.

I cut the engine harness from a donor car off at the firewall and took everything with me including the fuel pump relay, fuse box and ECM. I cut out everything not needed like the auto tranny and EGR wiring. Basically, I "powered" the donor harness by splicing it into the MG harness. I don't recall the exact details at the moment, this was 4 or 5 years ago, but I believe it only required 5 wires from the MG harness to accomplish. I studied both wiring diagrams, the MG and Lumina, (which is the donor) beforehand and carefully planned things. Actually doing it took a week of working a few hours in the evenings to create the whole harness and fit it to the car/engine bay. It really was pretty easy. It is definitely the cheapest way to go. There is code for both NA and boosted available for the GM OBD1 ECM, I'll let more knowledgeable people comment on that. I believe Craig Moates has hardware available that will let you choose different bins for different situations. Again, I'm not real familiar with it but I'm sure other people here can comment on that.

For the fuel system, I kept the original tank and went with an in-tank pump/swirl pot from a VW Jetta and ran 5/16 & 3/8 steel brake lines for my return and supply.

I'm confident the basic set-up I described above will work well for me as I continue to upgrade my current engine or go to a 3500 in the future.

-- Scott

[3.5MGB]

I think we're looking for different things from our conversions so I'm not sure how useful this will be for you but I have successfully added FI to my B. I decided to go with a GM OBD1 system and I'm very happy with the decision. I seriously considered a Megasquirt but at the time it didn't support GM DIS.
<snip>
-- Scott

Any particular reason you went with ODB1? I understand it is easier as it has less to modify but it takes a rom swap to reprogram. I'd like to be able to swap programs via a PC if at all possible. that would make a switch from road to track much easier.

Any SCCA racers on this list? I'd like to knwo a bit more about the fuel system requirements from someone who has upgraded their stock system.

[Scott_68B]

Any particular reason you went with ODB1? I understand it is easier as it has less to modify but it takes a rom swap to reprogram. I'd like to be able to swap programs via a PC if at all possible. that would make a switch from road to track much easier.

Price and the availability of support for the platform were the main reasons I went with it. Also, it is the stock GEN II ECM/code so it was a good starting point for getting things up and running and sorted out. Check this page out for some options for switching between bins:

http://www.moates.net/index.php?cPath=25_36

-- Scott

[ForcedFirebird]

Megasquirt kits are cheaper, and no need to remove chips. If you don't mind building one yourself MS1 can be had for as little as $150 new.

[3.5MGB]

Well after looking around I'm kind of leaning toward a Haltech ECM designed for the 60v6 or if I feel rich an XFI

I'm kind of liking the tools that come with them plus the data loggers as I want to add accelerometers in various places on the car. I'm also planning on spending a lot of time tuning the suspension and airflow for ground effects. So with all of that I'd rather exchange some $$ for some time. The megasquirt looked interesting and if I were 20 something I'd play with it but with my work schedule ...

Anyway Haltech has one that is plug and play for a GM harness so that's kind of where I'm leaning as it will support the SC when that goes on next year ot following winter. This year is all about getting the engine, brakes and basic suspension in and I'd like to drive it a bit next summer before I really tear into the car.

Thanks for all of the tips I'll keep them in mind in case I change my mind. I suspect you'll see more of the project as we get to some point where it looks like something has happened.

[85_Olds_Ciera]

Well after looking around I'm kind of leaning toward a Haltech ECM designed for the 60v6 or if I feel rich an XFI

Keep this in mind:

ECU 'flashing'


Many recent (around 1996 or newer) cars use OBD-II ECUs that are sometimes capable of having their programming changed through the OBD port. Automotive enthusiasts with modern cars take advantage of this technology when tuning their engines. Rather than use an entire new engine management system, one can use the appropriate software to adjust the factory equipped computer. By doing so, it is possible to retain all stock functions and wiring while using a custom tuned program. This should not be confused with "chip tuning", where the owner has ECU ROM physically replaced with a different one -- no hardware modification is (usually) involved with flashing ECUs, although special equipment is required.

[SappySE107]

Too bad wiring up obd2 into an MGB is going to be a lot more time consuming and more difficult to tune yourself. That and you can't drive and tune. No tuning on the fly, like an aftermarket or obd1 setup is capable of.

[3.5MGB]

Yeah I'm kind of finding that out. What with the cost of dyno time and the availability of cheap (relatively) diagnostic tools out there (O2 sensors, accelerometers and such) ...

I sure don't have the desire to deliberately go out and spend $1-3K USD if I could get the job done for $100. But I also don't plan on spending the rest of my life coming up with a good tune. Or paying someone else $300+ every-time I change a part on the car. And yes I see the plus side of the stock ECU and I'm really torn about not using it but ...

I'm kind of seeing the light with setting up the ECU driving the car, loading the data into the PC, making an adjustment, loading the ECU and going right back to driving the car. What with the instant feedback from wideband O2 meters and accelerometers and such, well that begins to feel more like tuning a holly or a weber than programming a computer.

Yeah it is not cheap but neither are the alternatives (I'm finding out). Maybe a mega squirt might do the trick and maybe not but I have better things to do that spend ALL of my car time trying to figure out the tuning. My time rapidly ends up costing more than the money I've saved (lost driving, lost track time, etc hey short summers up here in WI).

I still need to figure out how to identify a usable fuel pump and if the fuel pump management systems are worth what they are selling for.

And after all of that then there is the pressure regulators, injectors, etc, etc ,etc. See how my 'savings' have just been chewed up by dyno time?

If I'm going to sink $20-30K + USD into this project I'd rather it be in the car and not the tuners pocket. Save the dyno for the very last when I'm pretty satisfied that everything else is working right. And yes if you actually look at what it takes to make a competitive car then this is not out of line. And yes I'm trying to make sure that everything meets SCCA rules so I CAN race it.