difference between carb and EFI intake manifolds

[trulyalya]

Hey folks!

Does anyone here have an experience of retrofitting a carb intake manifold instead of the EFI one within the carb-to-EFI conversion project?

Mine was probably a twin-carb model transformed into a single-carb (a special spacing plate was installed). Is it just the matter of drilling holes for injectors, or I'll run into other problems/issues?

Fuel rail is another challenge for me. Is it just a plain tube with holes or there are some other considerations to keep in mind? Is it a feasible as a DIY project? Thinking of fitting flexihoses from injectors to a common reservoir with a pressure regulator (sort of a Jetronic-type fuel distributer)

One more question to engine gurus. I've just started reading some books regarding internal combustion engines. It's written there that it's better for the engine that the intake air is cold, rather than hot. What's the purpose of intake heater then?

[HoSS]

Just get a complete EFI manifold, they are easy to find.

If you mean the water pipes that pass into the throttle body, its to stop it icing, not to heat the air.

[muttleyd]

There are kits for replacing the carb with an injector, but is really easier to buy a complete efi manifold. Don't make much money and gets you round all sorts of problems including most of those you mention.

It's not worth the effort for probably less than £100

[FridgeFreezer]

What they all said - EFi inlet manifolds are cheap enough 2nd hand, I have paid £10 for some of them, complete, including a complete 4.6 setup.

However, there can be other reasons for converting a carb manifold, like keeping an original look, or availability of parts in some countries where LR's are rare.

You can drill & fit injectors (there are even special drills available that make the correct seat shape), or you can attach a single-point-injection (SPI) or Throttle Body Injection (TBI) unit, these are fitted to many small cars & also stuff that started life with a carb and the manufacturers moved to EFI (lots of american stuff uses TBI) these usually bolt in place of a carb, or at least are very similar in mounting style. Lots of the american stuff is standardised around the 4-barrel carb mounting style, which gives a huge choice of manifolds, TBI's, CFM ranges, etc.

Look on Summit Racing for 4-barrel-style TBI's, or on the megasquirt forums - they have a separate section for mounting injectors & sensors on different engines.

[trulyalya]

ergh... Guys, thank you for your replies. If they were just £100 per complete set - that would have definitely solved all my troubles) But I'm afraid the delivery to my place alone would cost much more...

I don't want to roll-back to TBI installs, I'd rather opt for sequential/semisequential squirting... But first things first, I need to sort out ignition. I decided to go for MS with full ignition management (two packs of quadcoils) driven by MS. And then, if everything goes fine, I'd continue with injectors. Now I'm just assessing the difficulty level and possible budget for this project.

[LandyManLuke]

Where abouts are you based? It might help give some context to people's replies.

[HoSS]

If you can get a MS sent to you, you can get a manifold, frankly its easier. I'm done.

[Mr Noisy]

Yep, just get an EFi manifold and save a whole load of problems!

Apart from injectors you then have to mount TPS and CTS, PWM or stepper valve.

Where is your location??

[FridgeFreezer]

I'd rather opt for sequential/semisequential squirting...

Really not required, and MS-1 does not do that anyway, it does banked squirting. Sequential is only really beneficial for idle emissions. It's a common FAQ. Flapper & hotwire are banked too, and sequential systems revert to banked/batch above certain loads/rpm as the injectors spend more time open.

[Mr Noisy]

Speaking of emissions, if I'm idling around 13.5:1 AFR, will I pass an MOT?

CO is 3.0%, HC is 1200ppm.

I have an exhaust has tester that measures CO, I can check on that, and if I am not misfiring i should be making very low HCs anyway.

Just wondering!

[trulyalya]

Well, I'm in Russia. I've just checked it on ebay, the estimated shipping for manifold alone is ~100 quid. Besides, I'd need a plenum, a fuel rail, etc. Probably, it's easier to get into the car and get to the islands :-) Anyway, when I come to that point and get enough money (which would probably occur late in spring), I'll first check it locally (from time to time there are some offerings - when people are tired with injector problems and go for carbs - but it's very rare)

There are several complications, though. First, my engine is 26D ( 'detox' according to Internet - probably it has something to do with its exhaust system - maybe it's somehow interconnected to the inlet system? dunno). Secondly, the previous owner of the car brought it to the exhaust specialist, who did a lot of welding in situ and actually made it a single whole out of a stainless steel tube - right from the exhaust manifold (which has proper connection between the downpipe and the manifold) through to exhaust intermediate and to the silencer in the back. So I'm a bit confused - how do I weld in those bosses for my lambdas. I would have to remove the cross-bar and then the whole exhaust system as a single unit (if there's enough space in the engine bay and the pot is large enough for such exercises).

I'm planning to obtain a 'clone' of MS2 from Latvia, which is cheaper both in terms of kit-price and delivery costs. It's sort of improved(/shortened?) version which drives the coils itself (doesn't need edis module) and apparently has a better circuitry for VR sensor.

I've ordered a wbo from 14point7 (spartan style), a bluetooth module and some cheap MAP sensor from China - gonna build an arduino-style something to get the plots of my current carb settings before I continue with ignition and on). Hope, it will be sooner than this summer...

[FridgeFreezer]

I'm planning to obtain a 'clone' of MS2 from Latvia, which is cheaper both in terms of kit-price and delivery costs. It's sort of improved(/shortened?) version which drives the coils itself (doesn't need edis module) and apparently has a better circuitry for VR sensor.

MS1 / MS2 can drive coils directly, you just need to built it to suit. By default the MS1 comes with one coil driver built-in. I would advise AGAINST knock-off copies of MS as it's not really in the spirit of the project, and you will not get a good welcome / help on the MS forums if you are using someone else's hardware.

The reasons for using EDIS are that it's cheap and easy and reliable, but MS can drive all sorts of configurations. Using GM LS coils which are logic-level triggered is probably the nicest solution.

[Quagmire]

I think that Fridge is putting it mildly when he says you will not get a good welcome on ms forums using a knockoff board. Any threads you do post will likely be full of tumble weeds and nothing else.... MS people are very friendly, knowledgeable and generous with their time, but will (rightly) see any attempt at using a kbockoff as taking the p1ss...

[Mr Noisy]

Yep, just buy genuine, pay the price, get the reliability and support

[trulyalya]

My mistake.

First, from what I've read elsewhere in the Internet (it was NOT that guy), I thought that MS started as an open source project (v1 - and mb v2 - still open source?).

Second, that fellow explicitly warned that his implementation was largely different from the original MS both in schematics and in firmware, and actually he was against calling it MS clone. Haven't made circuitry analysis or firmware testing, but definitely, things in common are motorola processor in QFP and MS software protocol.

Third, I haven't bought yet any control units - haven't made a decision. As far as I know that guy is now developing a completely different proprietary system that would (tada!) support fully-sequentilal injection, methanol, water, etc. and would be built on a completely different platform (cortex?) Besides, there is an AVR implementation of MS, which had also been designed as an open source but latter went commercial - would it also be regarded as a rip-off knock-off copy and copyright infringement?

Fourth, I'm still in hesitation if I want MS or any other system. Probably I don't want the proprietary systems (I can't fine-tune Lucas system, can I?). There are several models of known factory-built commercial systems in Russia (at a price of $100-$200) which are factory installed on the local cars. The only drawback of these systems is they are poorly documented and (my understanding) require some special costly programmer and software to fine-tune the engine, while megasquirt offers macosx software.

Frankly speaking, I can't really understand why it's possible at all to make all these systems proprietary. I mean, all these formulas are published in scientific automotive papers long ago. What's the subject of the copyright? Some PWM code to control injectors? Sensor mapping formulas? I mean, if it were my lawn-mover, I'd probably build my own microcontroller-based ECU (and would probably make it ©-protected ;-) - the cost of error would be minimal, and the whole project would be much simpler. If I were crazy enough, I'd probably build my own system based on my old Z80 to control my RRC. I mean it's arguable. But I got your point. BTW, any common efi-related sections on this forum? how much does it cost to become a supporting member?

Anyway I feel that first I need to get is an oscilloscope - even just to set up the crank sensor correctly or to check the MAP readings. Do you think that DSO quad would cover all my automotive needs?

As for MS - MS3 doesn't drive coils directly? I still can't understand what are the major advantages of fully sequential systems - ability to set it up for exactly for each cylinder (depending upon each cylinder's overall condition - I know i can even disable any particular cylinder in case, say, the valves are leaking)? Or it allows to squirt fuel only when the exhaust valve is closed (so that no fuel is wasted during the valve-overlap period)? Is this concept relevant across the whole RPM range? Or when running at full throttle injectors remain open all the time and I can not (and may be even do not need to) schedule their opening at certain periods of the engine's working cycle?

As far as I know, MS supports several engine position sensors (including camshaft sensor). Can it be used to improve the starting time (I adore the Nortstar DIS ignition systems installed in American cars, but they rely on a sophisticaed trigger wheel). Probably I can utilize my distributor for this setup. Actually I like the way it starts with carbs - after just a moment of cranking.

It seems I found the right solution to my one-piece exhaust system problem:

http://www.aemelectr...unt-3-inch-1175

I'd ask my dad to find a strip of steel and to weld in a suitable boss for the O2 sensor. Hope, drilling the exhaust pipe won't be much of a problem.

Hope, one O2 sensor would be okay?

Do I need knock/EGT sensors (I'd like to make it leaner for better fuel economy + am I right in thinking that leaner means less harmful in terms of ecology?)

The last question (which probably deserves a separate topic) is if MS allows you to identify particular cylinder missfire as it's done in modern ECU/OBD systems (the engine is pretty old and I can't be sure if everything is okay with it). As far as I know those systems constantly monitor the momentary speed of the flywheel and if they don't see the expected acceleration from the power stroke of each particular cylinder, they display engine fault warning naming exactly the faulty cylinder(s). Do they use the same trigger wheel, or a different one with much more teeth numbers?

Such system would be quite handy from my point of view, I tried googling but didn't find any projects of such kind so far :-(

[AncientGeek]

It's a common misconception that MS is or was open source. Although the code is downloadable for peer review it is very strictly licensed.

The cheapest way of doing MS is to buy the genuine board & processor from an official distributor and buy the other components locally.

The AVR based system is VEMS. It split from MS so long ago and is now so different that nobody argues about the licensing.

I know of a Russian system called SECU-3 which is fully open source and very actively developed. Afaik it is spark only.

[trulyalya]

Yep, SECU is ignition only, as far as I know, and it's sort of enthusiast's made. The factory systems available here are various versions of Январь ("January") used by AutoVAZ; Autron, Mikas, Corvette (GAZ-UAZ engines), not to name licensed Bosch and GM ECUs. Do not know what's the difference though - all of them read sensors, make the same calculations and give out signals.