Turbocharger

Right, I've no idea where the last four months went. I've had coolant "issues" with the engine for a while, and after running 1.5bar boost and chunky lumps of surge for a while I was leaving clouds of white smoke as I pulled away from junctions - around the same size and shape as the LR actually, it was quite impressive. I replaced the head and chronicled it here. I've run it in and I'm happy with it, so I've got to try to break it again. I've been running it just about static ie not using the vanes. It's pretty laggy that way, but it's safe. Today I've been playing with it again, tidying up some of the "temporary" measures I put in quickly at the beginning of the build. First off, it appeared the mounting for the diaphragm had been vibrating a little: The actual rubber diaphragm looked a little worse for wear too, and it was leaking air: I deluged the diaphragm in sealant and helped the integrity with an offcut from a Sainsbury's carrier bag: I took on the wise words above and modified the adjuster linkage too. I'm confident that it was working (see static testing) but I had some time on my hands while the sealant was curing. I even broke out the hole cutters to add some lightness. Quite proud of this one. Using the workshop air line I was able to pressurise the system and see what extension the diaphragm is giving at different boost levels. The carrier bag cured the leaks entirely up to 2 bar, and then there was a loud 'pop' and a jumbo air leak - you can see the hole in the picture above, in fact. I pulled out all the sealant, replaced the plastic bag with the strongest flexible membrane I could find (the peel-off backing from a roll of lead flashing tape, no less) and it's running well. I've had to back it off from 'really responsive' because the diaphragm can't move until 1 bar but it's still pretty good, 1 bar of boost from ~1500rpm and up to 1.7 bar at 2000rpm. Goes well Conclusion: I need different, lighter springs. Whatever I fit, I don't get any movement until >1 bar. Despite that, it's running well, performing better than a wastegated turbo and my understanding of turbos, back pressures, EGTs, revs, transient load, surge etc has all improved massively over the last twelve months so the project has certainly not been a waste of time.

Les- if you want to drag it down to Bristhole I'm happy to have a look at it with you - I'm on your side of town. Drop me a pm and I'll chuck you my phone number. I think if you keep winding the fuel up without finding what's wrong it could become a very expensive game.

Ooh! The link that Bish posted can supply 45' reducing elbows! Thanks chaps, that resolves an issue I've been grappling with for a while now. Tuko - for best airflow I think Jez's kind offer is your best option. What a nice chap.

I reckon it'll be the same with your snorkel disconnected. I also reckon there's a hole somewhere in the pipe which carries boost from the turbo / manifold to the injector pump - the turbo will spin freely, you'll see no black smoke and it won't make much power but it'll be the same as it ever was on pull-away. Mine melted on sommat hot, and it's now re-routed. Otherwise, start changing fuel filters. It must be fuel, a lack of air would give black smoke.

Umm.... <thinks> <lightbulb> "That's the effect I've been trying to achieve all these years!"

A roller brake tester needs to know the axle weights to work out the efficiency. Eg if a wheel produces 300kgs of brake force and has 400kgs of weight on it, efficiency is 75%. I'd assumed they'd need to weigh it each time rather than use a lookup table - that's what we do with buses anyway.

Your car is weighed every MOT, front and rear axle, to determine the brake efficiency (brake force / wheel weight)

Charles darling, for pizza I'm yours... What day do you intend?

I looked back through the votes up to Fridge telling us a few were within 20kg, and he's basically telling us it's a whisker under 2 tonnes. I'm more worried that I'm spending my time looking at the distribution of likelihood of weight of someone else's car, and trying to figure out my confidence interval...

I have to admit, I just use a non-waterproof one with a rubber boot over it - they're cheap enough so I replace it when it gets unreliable. So far I swapped one in three years.

Google up for Merlin Motorsport and use their Racetech gauge and electric sender. The thread is not tapered but will screw into your thermostat housing, and then you've got a gauge calibrated in degrees C, rather than "cold-warm-worry"...

Well, I reckon if the car's 6ft wide and you want to go up the sides of a tray too, say 4ft, I reckon you're looking around 14ft plus a bit for bends, bodgery and buggering up. If you want to support it too, best add some more. I really suggest you get a tape measure near your truck before you start ordering though...

Clean or dirty? Has that sidelight lens been replaced? How can we be expected to work with these inexact descriptions? (1965 kg with normal air in the tyres)

This seems to be going round in circles but I'll throw in my experience. On my 2.5NAD (no thermostat, no oil cooler, different system) the standard oil pressure switch would make the oil light glow dimly after the engine had been worked very hard and then brought down to tickover. The engine had 150k miles; my understanding was that the oil got thinner at high temps and the pressure was lowest at tickover (when the oil pump was spinning slowest). The combination of a worn engine and worn pump conspired to bring the light on, but the light would go out as soon as the revs were lifted off tickover. It didn't seem to damage the engine - it ran for another few thousand miles (and then stopped quickly, in a river, full of water...)

No no no Dave, you've missed the point. It's likely to give biggest gains at low speeds because the underbonnet soaks with heat, so if the engine can breathe cooler air and match it to fuel then you'll get more power. Your hand only feels cold out of the car window because you're warm. If you pass 15'C air over 15'C steel, no heat transfer will take place no matter how fast the air goes. (In fact, as the air speed approaches Mach 1 you'll start heating the steel but that's a whole nother argument!) For your engine, the answer to "Is it worth it?" is yes, if the temperature-related density increase is more than the pressure drop to get that air. For my example earlier, if you can move from 80'C air to 20'C air with less than 200millibar pressure loss (and assuming pipe and your time's free) then go for it.

I agree, it's absolutely not your problem if they're not able to produce a quote before their competitors have quoted, produced and despatched the same product. I just got a set of HT leads (and spark plugs) for my MG from sparkplugs.co.uk - they had to be made specially since they had none in stock so I guess it would be a similar process to get custom length ones. Quite impressed with their service - it took a few days but I was emailed every couple of days to let me know the progress with my order. Now I've got some bling blue leads (under the cam cover, under the engine cover, under the tonneau cover, behind the seats... )

NOx emissions form at high temperatures in the engine. Advancing the injection gives higher temperatures, higher pressures and better efficiency. Exhaust gas has (among other interesting properties) a high specific heat capacity, but it displaces the fresh air charge in the cylinder, so the EGR valve opens under part-load operation to allow the engine to run more advance than it would otherwise be able to without producing high NOx emissions. Disconnect it...

Bowie's hit the nail on the head. You need a 10yr old car with an MOT that you've owned for a year, and the dosh for 90% of a showroom new model and the financial backing to withstand the depreciation that you didn't have on the old car. Result- very small cost to the state, but headlines to displace this week's expenses outrage / sex scandal /data security issue. I'm calling it "Rustgate".

From the shape of the tubes to the way they join, I can't see why he's chosen this one as his demonstrator... Ebay cage linky

You could work it out. The benefit of cold air will be proportional to the temperature. At best, you'll go from underbonnet air at 80'C to outside air at 20'C, so the difference (in Kelvin) is 353/293 or 1.2, so you can allow a 20% increase in pressure drop in your pipe before you negate the benefit. To validate the temps, strap a min/max thermometer under the bonnet. This calc is true for race engines, lawnmowers and everything in between. It's more difficult to quantify the risk of water ingestion.... Sorry for bringing science into an otherwise interesting discussion!

Didn't L4NDY belong to Diesel Jim on here?

PM me your address, I've got 2 or 3 LR temp gauges on a shelf you can have to swap about...

Thanks guys - abuse, sarcasm, humour and the (hopefully) right answer, all within three hours of the OP. On the MG forum they'd still be tutting since I haven't washed it in a week... Mo - I was thinking a nice Perkins Prima would fit in the same hole... James - Did someone say I could spam pictures of my <cough> other car?

Just thought I'd post up a semi-bodge from the weekend. My earth strap parted company and looks like it'd been getting a little hot at the gearbox end for some time previous. I trimmed it back but I don't have a crimp or tool so I made up this clamp: I trimmed 2" of insulation, split and plaited the copper strands and then pushed the bolts through the plait and clamped it securely between the plates. It's not ideal but it'll last a couple of weeks while I source a heavy-duty earth lead, rather than rushing out to buy a cheapo auto-accessory shop one made of string. I can get a ring-ring lead at the same time and loop straight to the starter motor body too.

Yes yes, both leads and a full set of spark plugs are on order. Question is, do I need to replace one or both coils if the sparking problem follows the duff lead when I swap bits, even though it's arcing from the body of the coil?