complete novice looking for advice

[dave88sw]

Hi,

I've been doing a fair bit of reading around megasquirt/jolt and i'd really like to give it a go but ive got a few reservations before i part with any cash, mostly the issue of me not really having a clue what to expect or how to tune the engine post installation to get the best from the system.

Bit of background; I've got a swb series 3 with a 2.5 petrol from an early 90, took it off the road early jan because i simply couldnt afford the running costs as my everyday car. I had plans to fit a tdi and get it back on the road but it just seems too much like a cop-out to me, i know theres better to be had from the 2.5 and i like to be a bit different.

Now i've currently found 2 very useful sites showing other peoples attempts (both on 2.25's but they're so similar to the 2.5 i'm sure there's no issue there). One shows full megasquirt install but doesnt go into great detail. The other just megajolt alone, but does go into a little more detail.

megasquirt:

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

megajolt:

http://otly.church-walk.com/Megajolt/page1.html

I suppose my question really is; just how difficult is it to scratch build one of these systems?

I'd love to go full megasquirt with fuel injection, i gather the best way to do this is to fit a ford edis system and megasquirt is then capable of controlling fuel and ignition.

Alternatively fit the edis system and link to megajolt for ignition only.

(i don't need megajolt if using a megasquirt ecu?)

The fabrication i can do no problem, the wiring i'm happy with etc etc, all im worried about is the initial fire up and then fine tuning, i don't want to spend loads of money and have nothing to show for it.

How is the tuning done? I've never done anything like this before, is it out of reach for a novice?

Finally, what kind of gains can i expect? The finished land rover will be my only car, i need half decent fuel economy and power, if i do some mechanical work to the engine (skim the head etc) can i expect mpg figures close to the 30's? (17 is about best on carb set up)

Thanks to anyone who is willing to provide some input, i know i've rambled a bit but i would love to get everything clear in my head before i start, it's a lot of money for me to part with.

[fozsug]

2.5 here http://forums.lr4x4.com/index.php?showtopic=73239

[Quagmire]

When I did megajolt on my 3.5 it was available in kit form, and the price differential between it and megasquirt (kit) was quite high which at the time made it a good first step. However if there is any possibility that plan you to inject later, with mj no longer available as a kit I'd say you may as well fit megasquirt and use ignition only at first. Learning curve is a little steeper and there is more soldering, but with the info on here and the msextra site you should get there no probs.

[Hybrid_From_Hell]

Ring me for a chat ?

Nige

[TheRecklessEngineer]

Short version:

You first take a guess at the fueling and timing. It really isn't terribly hard: there is some simple maths you can do for injector flow rate/engine size to come up with your 'req fuel' number. The fuel table can then be taken from another engine of similar design - the 3.5 V8 table should be close enough. You should be able to come up with a reasonable spark map knowing the static and full advance timings of the distributor.

Next - try and start it.

Once running and up to temperature, use some clever software (tuner studio/mega log viewer) on your laptop whilst driving along to fine tune.

Job done.

There is loads of support available on here for MS. I'm sure if you run into problems and you post up the details, we can sort it.

[dave88sw]

Thanks everyone for the replies, sorry it took so long for me to get back to you.

Got a bit more reading there and that single point system on the 2.5 looks good, but ideally i'd like to go multi point.

My biggest question is what the fuel savings are like, what kind of difference does it make on a v8 over say a carb set-up?

Really the only thing i have to achieve is tdi rivalling fuel economy, otherwise it won't be worth it as i really would like to use the landy every day and i just couldnt afford 17mpg

cheers

Dave