Sam's 3.5 Disco MEGASQUIRT START/FINISH INSTALL THREAD! :)

[Mr Noisy]

If i may be so bold.... Maybe if Sam is finished with tuning etc, this thread should be trimmed and locked as was suggested a while back. Its way too good a thread to be filled with off-topic stuff. Just an idea for the mods as every time i see a new post i think something useful tuning-wise has been added, only to find it hasnt....

Fair play!

I guess we got lazy and decided not to proceed with trimming

My build is now finished indeed, had a little tuning run the other day just to keep things in check, no major changes etc, so yeah I mean as far as a start/finish thread goes, it is complete

[Hybrid_From_Hell]

I will look into excatly this !

Nige

[Mr Noisy]

Well folks, here's the spanner.

The car is great, just great great great and loving its MS personality.

So much so, it just loves the drink.

Just got back from a 300 mile laning trip and I averaged around 12 mpg.

BEFORE I GET STARTED, what do you reckon to this?

This is 80 mph cruising on motorway, 200 miles and 100 miles mixed road and Greenlane, and not much WOT this weekend tbh.

Stock 3.5 manual, 32.5" tyres, 1.22 transfer case, heavily loaded Discovery.

At 75mph I cruise at 13.2:1 and at 80mph it's running at 12.5:1

I have very high Kpa at cruise, not 50-60 Kpa like I would hope for.

Is it worth trying to improve things here, lowering my Kpa with a snorkel increase/air filter improvement?

Leaning out fuel map and adjusting spark accordingly?

Was thinking I could pop the end off my filter box and see how the Kpa changes to find out how restrictive the snorkel is, and go from there?

Help appreciated, car expensive

[need4speed]

I dont think 12mpg is actually too bad considering your doing between 75 - 80mph everywhere. Especially with a heavily loaded-up brick disco...

[discomark10]

yea I agree, I don't think that's to bad, but it would of thought maybe a bit better being ms.

[Hybrid_From_Hell]

Fit new driver OSF may cure problem

Nige

[landroversforever]

Fit a set of nice balletpumps to the OFSDriver rather than the DocMartins

[CwazyWabbit]

Chuck a diesel in ..... I'll get my coat

[Mr Noisy]

Yeah, kind of the responses I was expecting.

I mean, I do believe, now that I have found out that I have a P5 spec cam in my stock 3.5 (not as torquey as land rover cam) that my pokey little 3.5 with no torques dragging along probably 2.6/2.7 ton of loaded up steel wrapped sandbag tyred square brick roof lighted suspension lifted metalwork everywhere and spares and tools to the nines disco is probably struggling quite a lot at cruise, hence the fact that at 2000 rpm cruise i am having Kpa often in the 80s

Forward facing snorkel head should compensate for its own restriction at pace I would have thought

Maybe I just need to cruise at 65mph and not 80

Will head out for a run one evening and post up findings

Thanks chaps.

I'm not too fussed by the way but you know, when your mate does 450 mile on £100 diesel and you do 300 on £150 petrol there is something of a thought provoked!

Cheers!

[Mr Noisy]

Anyone got any actual ideas rather than ballet pumps/new driver/slow the **** down?!?!

Or is that literally the best option

[CwazyWabbit]

Anyone got any actual ideas rather than ballet pumps/new driver/slow the **** down?!?!

Or is that literally the best option

Not that this is much help but, Victor (the guy with the 6.3 chevy engined defender) would get 20 mpg on a run when that engine was still in the Disco. Not sure what speed he was driving though.

[elbekko]

LPG

[Chazza]

I agree LPG, if the cost of the conversion and the distance you drive makes it financially worthwhile, but you will need another fuel/ignition map.

What sort of petrol do you use? I can get an extra 4mpg using 98 octane fuel, compared to the 91 octane carp sold in Oz.

Use Iridium spark plugs and Magnecore leads for the best possible spark, if you don't already.

Divesting the car of extra weight and cruising as you suggest at 65mph, will save heaps as well,

Cheers Charlie

[Hybrid_From_Hell]

at the mo you have a power maw

back of mid and top end spark by 5-10% and entire ve table by 15% then datalog

and let it reprogram and tweak afr table to run leaner esp cruise cells the spark less helps offset heat from leaner running

I had this as a 2nd msq in my ecu and it was slower but vastly better on fuel

[Mr Noisy]

Hi guys

Ok thanks Nige, will try to build up a pair of softer tables.

I do get the impression that it is simply pouring fuel in whilst cruising because its been mapped with WOT in mind at all times.

I have read the associated threads regarding economy tuning so have a basic understanding of how the spark and fuel tables interact.

Is it true that if I am cruising at 75 in 5th, the higher the AFR the cheaper it is to drive, in simple terms?

What do we think is a safe ceiling? 15:1?

I'm not looking to go super lean to make an Eco beast that might melt pistons, just looking to stop any fuel wastage on cruise.

[Bowie69]

Not more than 15 would be safe IMHO

Also, no-one mentioned gearing, you might have a 1.22 box, but you have almost 33" tyres, this won't help as the engine will be labouring all the time, hence your high MAP at cruise.

Swapping to a lower ratio box may drop your top speed a little and bring your revs up, but it will most likely be better to drive.

My Rangie, when full-bodied on the motorway, caged, towing a ton and loaded up with people and kit in the back managed 15MPG, that's a breathed upon 4.0 with an autobox, I would expect you to be getting better than that tbh... especially with a manual.

[discomark10]

Do you run a map for cruising and one for playing? Or just one universal map?

[Bowie69]

Me? One universal map.

With a 50-odd mile motorway/lanes round trip and 6 hours playing I tend to get 10-12mpg then..

[TheRecklessEngineer]

Is it true that if I am cruising at 75 in 5th, the higher the AFR the cheaper it is to drive, in simple terms?

Partially, yes. Injector pulse width might be a better measure though.

[Mr Noisy]

Thanks Bowie.

If I can cruise at a decent pace at even 14.7 I'd be happy!

I am aware that the over geared vehicle will be labouring, thus high throttle at low rpms.

This is the root cause of the problem if you like because it drives my AFR right up to the top of the AFR table on my current map.

I have read on various threads though that economy comes primarily through low rpms, because with high rpms comes more frictional loss and heat wastage etc etc.

Ie making the power required to cruise at 75 at lower rpms will always be better than at high rpms.

I guess firstly I need to decide on my cruise speed.

Is 75 simply too fast for my vehicle to efficiently cruise?

I think 75 is probably about right but I need to carry out some tests against Kpa I think.

Top end speed is a non issue and lowering the ratios would be handy but its not really a financial/time available option at the moment. And I refer back to my rpms point above.

Other points are:

Most information online suggests advancing the cruise ignition areas to help with slower burn on lean mix.

As such, wary of nige's point about heating, I am considering leaving my spark table as is, plus it's still a dark art to me. Thoughts on this?

And a final point, I feel my current table is dialed in now, but when cold after first start I get a flat spot when blipping the throttle from idle. This is only for the first few minutes but it can be difficult when manoeuvring out of the garage as I lose the motor when I blip.

Do we think this is a WUE or AE issue?

Thanks hugely again for help!

[Bowie69]

Using another spark table, but then I'm 4.0, so slightly different to yours... I think

[Mr Noisy]

Well, time for an update methinks

After just about a year of MS I can safely say it has been the single best thing I have done to my LR that has made the most overall difference to the quality and reliability of usage, the transformation is almost immeasurable.

On that basis, I'm chuffed

It's also great to be part of the MS family

Which leads me onto my next point!

Apart from a niggle in April where I had an injector go bad I have had no engine problems since the build.

Nige, my eternal saviour, supplied me with a kit of various MS spares (including some injectors!) that I now keep in the car for next time!!

Other than that, great, until Sunday when I made some trouble for myself

I have, somewhat cavalierly, been running on Wideband since installing, using AFR target tables to keep my mixture in check and a dashboard guage to help me tune my throttle pedal position when cruising, amazing how much you can let off to lean out whilst still maintaining the same speed.

Over time this has included many puddles and crossings of a shallow Corwen Carwash.

However, this Sunday just gone, after all this rain, the 18" Carsplash was back to its 48" winter Carwash, which I sort of floated across, and back again! D

This meant the Wideband was submerged for probably around 60 seconds in total.

Whilst driving home after emptying my spotlamps I noticed my air fuel gauge had stuck, or was moving very slowly, around 9:1.

I read online the sensor can suffer thermal shock and Nige says you musnt dunk them, so I was like "bugger".

Anyway, opened up the laptop, set controller authority to 0% and carried on my merry way.

After a nights rest, the sensor does now appear to be functioning correctly again, but I haven't driven the car.

Plan is to take it out and blowtorch it, then free air calibrate again and see what happens.

New ones are about £50 so not too bad.

ANYWAY, main question is do I really need that Wideband in all the time???

My VE table is clearly dialed in now, I'm just wondering what's best.

Advice would be appreciated, how much of a downside will going back to narrowband be?

All comments appreciated!

Thanks!!

[FridgeFreezer]

ANYWAY, main question is do I really need that Wideband in all the time???

You don't need it in any of the time - widebands are only really useful for initial setup, once you've got a good map in there you can pop a narrowband in. I've never run a wideband in anything.

[Mr Noisy]

Ok fridge, thanks.

That was my gut feeling tbh.

Lot of expensive electronics dangling down under the car and it was just a matter of time!

I cannot/do not use AFR tables on narrowband iirc?

[FridgeFreezer]

I cannot/do not use AFR tables on narrowband iirc?

No, the narrowband cannot tell you the AFR so you can't run AFR targets, what most people do is use AFR targets to dial in the fuel map, then once it's right, leave it alone and run narrowband.