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dave88sw

Megasquirt Series

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Hi,

Right, having spent the last 12 months fitting a 300tdi to my series 3, i took it for a drive to the MOT station last Monday. It passed but...

I hated every second of it. Diesels not for me, short bursts of power when the turbo kicks in, then you need another gear and series boxes don't change quickly.

Sooo, I realllllllllllly want to megasquirt the original 2.25. The engine is in good nick, its not long since it was rebuilt and i think it would benefit greatly from a decent fuel and ignition system.

The engine already has the twin choke webber carb off an early 90/110, so has the larger inlet and exhaust manifolds.

Now, i have a pretty good knowledge of injection systems (i'm a mechanic by trade) but i've never started from scratch or looked in great detail at ideal running conditions so fuel and spark tables will be new to me but i'm eager to learn.

I'll try and update this thread as i go along, hopefully encourage a few others to go down this route.

So, what's the point in this post i hear you ask? Well, i've hit my first stumbling block. As the engine is still out of the vehicle, i'd like to get the hardware mounted up first, like the trigger wheel and injectors. I can buy an aluminium extrusion from triggerwheels.com that's perfect for the fuel rail and they also do weld in injector bungs (i have a friend who can ally weld). The problem is, the ideal would be to have the injectors mounted at a 45 degree angle, but if i were to do this, the fuel rail would want to occupy the same space as the carb currently does (and where the throttle body will need to be). What would be the best work-around here? Have 2 short fuel rails connected with a flexi in the middle. Or mount the injectors at a steeper angle enabling me to use one long rail?

If i absolutely had to, i might possibly be able to get some tube bent to clear the throttle body but it makes fitting injector cups much more difficult.

Thanks for any input

Dave

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You could manufacture your own inlet manifold if you can ali weld? Make it much improved from a flow POV, and optimise the injector positioning :)

Great idea to get it running on the stand, really will make life a lot easier :)

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Lovely idea, it would probably make more sense but although my friend can ally weld, i don't think he'd have the time to scratch build me a manifold.

I think i prefer the idea of one continuous fuel rail, seems to me like i'd be asking for trouble running a high pressure rubber fuel hose directly above the exhaust manifold. I suppose the first step is to get the manifold off and do some mocking up, see what is possible with what i have :)

Thanks

Dave

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Im guessing you have come across this

http://www.melsteve.plus.com/LandRover/

Would turning the elbow with the throttle body 90^ so it comes over the top of the engine give you enough room to run the fuel rail on the far side of it?

It may also be worth looking at what injectors are available, I used some Mitsubishi ones as they fitted into the flapper V8 manifold, were short and had small dia inlets that could be made to fit inside 1/2" stainless tube, well when the weld seam was ground off the inside of the tube they fitted. I didnt bend it but welded it together with preformed bendsP1020375_zps97a6c9fc.jpg

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Nice project :)

Would using a throttle body injection unit not be a huge, huge amount easier? You are going to bypass a massive amount of hassle getting each injector mounted / angled right / fed properly, and to be honest, the power / efficiency gains on an old engine like a series are going to be totally minimal...

If you check out www.ep90.com, TSD from here did the same to a ford essex v6 with good results. I was going to do the same to mine, and even got as far as buying everything needed bar a fuel pump, but circumstances have changed and the 90 is for sale...

If you are interested in a brand new professionally built MS2, trigger wheel, GM injection throttle body etc drop me a PM! (There's also EDIS 6 & Coils but they are of less use!). Sorry for the shameless ad! ;)

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Cheesy

I have seen that site thanks :), he's done a very neat job and i like the idea of the spacer blocks but it seems a lot of extra work. I'll see how pushed for space i am when i get the manifold off, that might be a possibility thanks :), it's possible that the adaptor to bolt a throttle body on could potentially push the whole lot out a bit and give me just enough space (even better if it is close enough to mount the fuel rail to it) but as it is, it won't fit with the carb. I was hoping to get the injectors mounted alongside the carb so i could take one last drive with the carb and really be able to gauge the benefits properly but it's not the end of the world if i can't.

Your fuel rail is very neat and has given me a few ideas thanks :). I was hoping to use the commonly found bosch injectors simply for ease of finding parts but shorter ones are around that might make more sense.

Jon

Admittedly having only really skim read the megamanual, i was of the impression that the ideal was 45 degrees pointing in the direction of airflow but it's not particularly critical and having read a few posts over on msefi, it seems a few have the same opinion, the only advice seems to be to carefully choose the injectors to ensure a good spray pattern as otherwise you'll just be shooting fuel at the opposite side of the manifold. You are probably right though, throttle body injection is likely to be the easiest route, it's certainly something i'll consider but i think i'd prefer port injection. That's certainly not to say i wouldn't be interested in some of the parts you've amassed. I'll see where i am with the manifold this week and let you know, if nothing else i will need a ms ecu :).

Thanks guys

Dave

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They are a Bosch injector, and pretty common in NZ at least, pretty much the same as the Thor ones I think. Just go to a wrecker and see whats available and looks like it will work. One thing I had to do though was replace the seals on the bottom of the injector with an viton O ring, this saved any machining of the manifold.

The fuel rail is pretty simple, made with a drill, a hacksaw, a file, a vice, 8mm 3/8 socket, dremel and a Tig .... The injector cup bits were cut to length then squezed in the vice with the socket in the middle to give the flare. Then gave the weld seam a quick file to get rid of most of it. Then the cup went into the drill chuck and turned on and cleaned up the inside with a dremel... a lathe would be much easier! Then tacked up the cups and drilled through the main tube and knocked all the burrs off before I fully welded it. Seems to work, I wish I had of used a newer regulator though as it would have eliminated the rubber hose in the high pressure side.

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One of the first things I would be looking to remove from the equation, if I were messing with the manifolds, would be the hotspot between the exhaust and inlet, this will have zero benefit on an injected engine, in fact quite the opposite as it would be warming the charge before entering the engine.

As you have the inlet currently, you could chop the flanges off and build the custom bit from there?

Have you thought about using a diesel inlet manifold, to which you would may find it easier to mount a throttle body to, and may even open up the possibility of mounting the injectors in a better position. It also looks much more like a plenum, there are advantages aside from just aesthetics! :)

Not sure if the 200TDI manifold would bolt up, but this may offer other improvements -remember in the 2.25 tuning kits that were out there, one of the big expensive bits were the inlet manifolds, they wouldn't have changed them out if there wasn't a good reason to.

If I was going to the bother of MSing a series, I would want to get the most out of it, including probably a compression ratio increase, and at least some port-matching on the head.

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One other thing to bear in mind while it's all out - have you considered a 2.5 petrol from an early defender? I had one in my old series and it was considerably more powerful than the 2.25 it replaced. Other than that it was identical externally other than the throttle linkage so dead easy to fit...

They can be bought for absolute peanuts as well as nobody wants them...

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have you considered a 2.5 petrol from an early defender?

Depriving another boat of a decent anchor? :hysterical:

Seriously, there aren't enough MS powered Series vehicles. With EDIS and a sensibly specced injection system, it should be a very nice drive.

Aim for driveability rather than maximum power for best results. Twin staged throttle bodies (single housing, with two throttle plates) would be my favourite, maybe one of the ones VW used to favour with a tiny primary and large secondary throttle. That would combine best maximum airflow with best control around tip-in (where the throttle is just opening). My 3.1 Essex (with Chevy TBI) was much, much more controllable on efi than it ever was with the standard Ford/Weber setup, but it would have been much better again with smaller throttle bodies.

I think many people over estimate the benefit of port injection over TBI, especially in fairly simple manifold designs like most MS conversions.

I often wondered if one of the Bosch SPI units could be made to work. They were fitted to things like 1.6 Peugeot 405, around 90HP ish so in the right size range for a Series lump, and they always looked to me like they might fit easily onto a 2.5P inlet manifold. The injector design was similar to the chevy design, but I don't know if they were sized to be interchangeable.

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If you start messing with a petrol engine, compression ratio is the first thing I would look at; 8:1 is standard, were the octane number of unleaded fuel these days easily allows 10:1. I build a 2.5 petrol with a 2.25 head (with 2.5 valves), skimmed as much as possible to achieve 9:1 ratio.

The higher compression ratio will give you better power but also makes it more efficient.

Daan

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Thanks for all the advice :)

I will definitely consider throttle body injection, i suppose the only thing swaying me to port injection is that we have about 5 old manifolds from various vehicles at work with injectors in them and a suitable throttle body from a 1.8 freelander that could very easily be mounted to the manifold (i'm not a cheapskate but you can't beat free parts).

I certainly plan to have the compression ratio upped, i am starting with an 8:1 head (earlier engines were 7:1) so it shouldnt need too much off to get to 9:1 (reading about, it seems difficult to get them above 9:1) but for now, i need an engine back in the car and running, so i'll get my spare head reworked ready to drop on later.

Right, so i finally got a chance to take the inlet manifold off, with the carb off (twin choke webber), it looks a lot more do-able with port injection (although throttle body would be even easier) The manifold has 2 small openings beneath the carb (as it was a twin choke) depending which route i go down, i can either open these into one big opening or if i go for a twin choke throttle body as suggested, i'll do my best to find a throttle body with similar opening and save the hassle.

If i were to port inject it, bearing in mind i have the parts, would it really be much more hassle than a throttle body? Would there be any benefit at all?

If i were to look for a throttle body, are there any further suggestions to donor vehicles? hopefully something readily available, i like knowing i can find spares :).

Thanks guys

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Well you have the parts laying around so you should be able to see how much more hassle it will be!!

Drilling manifold and welding in bungs

Some way of retaining injectors (possibly fuel rail)

Fuel rail

Fuel pressure regulator

Some sort of adaption to the throttle body

A few wires

Obviously the throttle body injection will be easier, although Im not sure how limited it will be for injector choice, high/low impedance and flow rates etc. On the other hand I wouldnt be surprised if there is something around that will bolt on where the Webber went, I know there is for IDAs and DCOEs not sure about the smaller twin choke carbs though (they are not cheap either)

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All the TBI injectors I've ever seen were low impedance, and of a very different design to the common port injection types. At least in chevy form, there is a fair range available, at the high end they are like lightly calibrated buckets - I have a pair of 'police spec' injectors for a big block (only 2 injectors feeding a 7L V8). If you dialled up the fuelling they were capable of flooding and stalling a 3.1 V6 while driving down the road!

OE TBI units usually give you fuel rail, fuel pressure regulator, idle motor all included. All the ones I see on the uk bay are for probably a bit undersized. The injector in a modern 1.2 *might* be just about big enough to support a LR 2.25 (remembering it's sized broadly on power output, not swept volume) but even if it were, the throttle plate would be on the small side.

There were Bosch Motronic units for larger engines, e.g. 1.6 Peugeot, but I suspect they were rare in the UK even when they were current.

Twin choke unit from a Chevy 2.8 is probably too much throttle plate for a LR 2.25?

The TBI units intended for carb replacement usually use normal Bosch port injection type injectors, as they anticipate fitting multiple units on classic cars. There is, or was, one that replaced SU carbs and looked standard at a casual glance, but that won't be cheap either I'm sure, plus you have the same injector sizing issue.

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So basically, almost all throttle bodies are likely to be old, worn out and quite probably not big enough.

I'd say that was a pretty good reason to go with port injection.

For a throttle body, I would go down the local scrapper with a tape measure/steel rule and see what is about, pick the common makes and you could get something very cheap to even buy a new one of!

Rover 1.4 bodies are cheap, in fact I may have one sitting on the shelf here....

Looked at a diesel inlet yet?

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As you can probably guess from the lack of activity on this thread, nothing ever really happened with this.  I got it running on carb and distributor long enough to gain an MOT and then parked it up and never used it.  Pointless i know but life kind of got in the way.

Anyway, the idea has never left my head and i still want to go ahead with it.  Plans have changed multiple times but i have got some parts together. I've got an edis 4 and a coil pack, just need to mount up a trigger wheel and sensor and crack on with the ignition side.

Fuel wise, i've looked at loads of different throttle bodies but most are 20+ years old now, probably pretty knackered and possibly a bit over-complex for what i need. 

Tell me if it's a stupid idea but what if i was to make an adaptor to go between my manifold and a throttle body (literally just a butterfly) removed from a 1.8 freelander (it looks about the right size).  In the adaptor i could weld an injector bung to take a single injector taken from a multi point system (possibly V8 as they're plentiful).  That would give me my throttle body and injector and i could use an in line pressure reg.  It would also mean all the parts are easy to source and i imagine it would be easy to make.

Any thoughts or should i just stick to finding a throttle body injection unit?

Thanks

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I'm not sure if it would be too big for the engine, but I still have a throttle body injection setup from a US v6 somewhere in the shed, the old 90 went as did the rest of the megasquirt setup.. I put it on ebay a few times but it didn't sell. Drop me a PM if you want some more details.. 

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I don't think you'll get the required fuel flow with just one RV8 injector but the rest is relatively sound.

The thing you will miss our is all the careful airway shaping and optimization you'd get with a proper TBI unit. 

Personally I'd do it right and make up a spacer between head and manifold and for two, or even 4 injectors that way.

 

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8 hours ago, Bowie69 said:

I don't think you'll get the required fuel flow with just one RV8 injector but the rest is relatively sound.

The thing you will miss our is all the careful airway shaping and optimization you'd get with a proper TBI unit. 

Personally I'd do it right and make up a spacer between head and manifold and for two, or even 4 injectors that way.

 

I can see what you're saying, anything i could make up would never be as good as a part made to do the job, however, i'm struggling to find anything suitable.  Also a minor detail but a lot of the TBI units appear to take a large flat pancake air filter fitting that wouldnt go in my engine bay, so an adaptor would have to be made for that.

There's no argument that would be better but it would be a lot more work and probably cost a fair bit as i'd have to have the adaptors made up.  What if i were to put 2 injectors in the adaptor i described before? I can't help but think it would still be a big improvement over the carburettor and it's something i could revisit later on and improve on.

Thanks

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I seem to remember rover V8 injectors are not really that high flow at all, there are much better/higher flow injectors out there for little money, bonus is they would be new as well.

Comparing mpg 2.25 vs RV8, about the same? So in theory you may need up to 8 Rover V8 injectors to run the 2.25 (ignoring any breathing room they may have). I don't know what flow you will need, but stands to reason any injector in a TBI will be higher flow than any multi point system with similar engine size/power.

 

A chunk of 30mm aluminium, drill, hole saw, a file and some time would get your spacer made up, so could still be cheap. You can buy drill bits specifically for cutting the injector seats (trigger wheel a sell them, among other places) and they also sell the fuel rail you would need.

Not pushing you in a certain way, just saying there are other options :)

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Nice idea..

The 2.5 diesel inlet manifold looks the best option IMHO. Make up some little Ali spigots for the injectors to go in, which will seat nicely on top of the intake runners, get your mate to weld them on, then drill and finish machine to suit. You can do the fuel rail with some extrusion with holes drilled to suit your spacing. Add a fuel pressure regulator and you've got that part nailed. The little regulator from a Toyota 4AGE would be perfect here. It bolts on, and regulates the return. Simple! 

For the throttle plate, try something like this: http://www.ebay.co.uk/itm/262760495140

A little Ali plate made up with holes mount that to, then welded to the inlet of the manifold will get you sorted there. 

You could have it running in no time :)

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100mm might be a bit overkill! :D

But yes, something like that would be great, as it gives a spot for the TPS to sit as well...

Complete with adapter plate for your mate to weld in position: http://www.ebay.co.uk/itm/Universal-65mm-2-5-Intake-Throttle-Body-CNC-Billet-High-Flow-w-Adapter-Plate/152038128048

The 2.5 diesel inlet manifold looks a bit more compact, though a 200TDI would give you a plenum of sorts, and more meat to fix stuff to, if that is what you are after :)

http://www.ebay.co.uk/itm/LAND-ROVER-DEFENDER-2-5-NA-DIESEL-MODELS-GENUINE-INLET-MANIFOLD-ERR1627-/371541976763?hash=item5681a0a6bb:g:~fcAAOSw--1WqL52

http://www.ebay.co.uk/itm/LAND-ROVER-DISCOVERY-200-TDI-2-5-DIESEL-ALLOY-INLET-MANIFOLD-HRC2010-1-/251526849877?hash=item3a902b2555:g:XHsAAOxyuR5TbOwA

Could even mill the front off the 200TDI one and weld the throttle plate adapter above straight to it?

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Injector bungs: http://trigger-wheels.com/store/contents/en-uk/p230.html

Drill holes in manifold, insert, weld?

Fuel rail: http://trigger-wheels.com/store/contents/en-uk/d51.html#p192

Injectors, if going multipoint, you could try the RV8 ones and see if they work OK, it is  certainly a cheap source. As long injector duty cycle doesn't go over around 80% you should be OK.

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Lol. Yep, 100mm might be a bit much :D

Nice finds, Bowie! I forget the 200 manifold bolts up to older engines. Definitely a good option. 

Interested to see how this turns out. 

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