Tell me about...turbochargers.

[tommotech]

Here is a link to some good information, on turbochargers and fault finding, from Mahle.

 

http://www.mahle-aftermarket.com/c125790900540ac0/vwcontentbyunid/49a30ee0582f2c0cc1257a5500658718/$file/turbo%20damage%20brochure%20mo-2-612.pdf

[D Spares & Tyres]

I will report back once I've investigated a bit.    Must say, part of me quite likes leaving clouds of blue smoke - feels quite nostalgic.  

 

The rest of me grinds its teeth at having to make increasingly frequent purchases of hatefully expensive newfangled oil.

I had a Citoen ZX which blew it`s turbo. It was getting through a gallon of oil each way to work (around 8 miles )

 

Luckily I have loads of used oil knocking about

 

It didn`t smoke too bad unless you floored it, but I did because it was funny. The back of the car was literally dripping with oil.

 

Ran it like that for 4 days as I needed it for work and fixed it over the weekend

 

I almost missed the smokescreen when fixed. Sorry to anyone on here who may have been following

[Pillock]

My experience was rather more sudden. 1.9TDI with variable vanes in a Leon, it went from "what's that slightly odd noise" to "let's dump the contents of the sump out of the exhaust" in about fifty miles. Smokescreen, no power, dead. I parked it up in a haulage companies driveway to wait for breakdown, a chap ambles out to ask what the problem was.... Nice fella, think he was looking to help if he could. I started it up, engulfed the place in smoke and he just said "Yeah. No. Good luck" and hobbled off, proper terminal.

[Stanky]

Since the topic has been raised by New POD, I have questions about remapping a turbocharged car.

 

Now, this is purely hypothetical as I own a dismal NA Almera - however, some cars - such as Saab 9-3s from another thread - come with identical engines with different maps giving different power outputs. If one were to purchased a pre-loved lower spec car and have it remapped to match the map of the higher-spec one (+25bhp on a 150bhp engine) how would this manifest iteself?

 

1. Would the power band be narrower as a result (i.e. more boost, through a narrower range)

2. Would the engine explode in a ball of fire? (i.e. are all the other internals identical, or do manufacturers use different internals depending on the state of tune?)

3. If, for the sake of argument the turbo begins to boost at 2000rpm, and I drive home on a motorway on boost, then come off the motorway and potter at sub-2000rpm for the ~4 miles between the motorway and home, can I safely turn the engine off as soon as I get home, or should I still leave the engine running for a couple of minutes every time to allow the oil to continue circulating and cool the turbo?

 

I know literally nothing about turbocharged cars in the real world - I understand the mechanics of them, but living with one day to day would/will be a new experience. I wish for that experience to not be either short-lived, or expensive. Or both.

[Jim Bell]

Not safe at any sped.  Turbot may kipper your tie rod and lead to herring loss.

[twosmoke300]

All I know is is that a lpt Saab 9-5 remapped is a nicer road car than the aero cos the little turbo spools up quicker with less lag .

[filthyjohn]

LPT and HPT versions of the same engine are usually identical apart from the boost pressure. Volvo sold two versions of the B230 side by side, one with 135hp, one with 165hp. The only difference was the strength of the diaphragm in the wastegate actuator. Everything else was identical, the turbocharger itself, the ECU, even the map! You can whack a manual boost controller and increase the boost from the 3.5 or 7psi (of the factory settings) to 11psi for 190hp without changing a single part.

 

 

Turbos are amazing, if you don't have one you're just throwing your exhaust gasses away for no good reason.

[Dead_E23]

I had a look inside some of the pipework today, and am very slightly further forward.   On the inlet side, the pipe from the turbo was remarkably free of oil, which I found encouraging.  There was a lot of gunge in the pipes after the EGR but that seems to be normal for these engines.  

 

Having read the excellent Mahle fault finding guide that tommotech posted above, I suspect that dink may be onto something with his suggestion that the oil return pipe could be bunged up.   Unfortunately I had limited time today and didn't remove it because I suspected I'd have to make a new gasket for the top (or oil would piss everywhere, or there would be some other poor outcome that would result in domestic disharmony).   Next time...

[Dead_E23]

Today's investigations revealed that the oil return pipe was as clean as a whistle and not remotely bunged up.  

 

Good job I didn't remove it last week; reassembly took far longer than expected due to an oil leak from the flange where the pipe bolts on to the turbo despite both surfaces being spotless.  In the end, I assembled it with a smear of Loctite 5922 even though everything I've read says not to use anything at all.  Expect I'll end up regretting that decision.

 

I've also put one of those shit 'oil stop leak' magic potions in the oil to see if making all the seals swell up improves matters at all.  I'll probably end up regretting that too!

[RoadworkUK]

Being very silly indeed, I will be putting a Large Hadron Collider sized turbocharger on The Audi at some point soon. That should be an education for me.

[Luckythirteen]

Probably belongs in the stupid question amnesty, but I've polluted that enough for one day, so...

Say you had a 4L V8, would a turbo for a 2L four pot on each bank work out ok? Or one big turbo, say from a 4L diesel?

[dollywobbler]

Probably belongs in the stupid question amnesty, but I've polluted that enough for one day, so...

Say you had a 4L V8, would a turbo for a 2L four pot on each bank work out ok? Or one big turbo, say from a 4L diesel?

 

Try this. It won't teach you very much about turbos, but shows the sort of ridiculous things you can do with them.

[RoadworkUK]

Probably belongs in the stupid question amnesty, but I've polluted that enough for one day, so...

Say you had a 4L V8, would a turbo for a 2L four pot on each bank work out ok? Or one big turbo, say from a 4L diesel?

 

Any turbo or turboes on any engine will work out just fine until you go for a drive.

 

Invariably a N/A engine will not be set up for forced induction, the internals, the rods and pistons might well go all bendy and melty if you wham a load of boost at them. But hey, you'll only know if you give it a go.

[davidfowler2000]

Any turbo or turboes on any engine will work out just fine until you go for a drive.

 

Invariably a N/A engine will not be set up for forced induction, the internals, the rods and pistons might well go all bendy and melty if you wham a load of boost at them. But hey, you'll only know if you give it a go.

 

Some work, some won't. Just do your research first. I have a Volvo 740 2.3 NASP and a 760 2.3 Turbo and AFAIK the only differences between the engines (apart from the additional turbo charger of course) is motronic electronic fuel injection (K-Jet mechanical on the 740) and dished pistons to reduce the compression ratio and increase the CC a tiny bit. A turbo engine should always have less compression than it's NASP counterpart 'cos the turbo will make up for the loss but it goes to show that some engines are turboable with little or no difference.

 

In addition to your V8 twin vs one big one question, a twin setup would be more expensive and fiddly to set up but would be less laggy.

[Luckythirteen]

Right enough, the Haynes manuals for the T5 and the Legacy list different compression ratios for turbo and N/A. So probably different bits in there.

Surely if you keep coolant and oil in check, you'd stand a better chance of not blowing the engine.

Although, a burnt out piston or bent rod would be a desk ornament for the discerning shiter...

[Junkman]

God and Fred Duesenberg used superchargers. Nuff said?

[Luckythirteen]

Grandad's Merc previous to the current one was a C220K and you couldn't really hear the supercharger on that. Sis_13s previous Cooper S had a daft induction kit, and you couldn't miss the sound of it. Strangely, she hasn't bothered on the current one.

I like the noise for a while, but the constant dentists drill noise would do my head in eventually.

 

Presumably the same requirements around strengthening and coolant/oil apply to those too?

Actually, I'll start another thread rather than derail this one...!

[phil_lihp]

I have a 2.3 LPT in the 940 and to be honest I wouldn't know it had a turbocharger at all, there's absolutely no feeling of boost, I assume it's very subtle and would be noticeable by its absence.

 

A workmate at a previous job had a terminally abused 1.8TDCi 2003 Focus saloon which did 30k a year and was treated to a basic oil change once a year (and washed every 2-3 years).  That caught up with him at around 170,000 miles when the turbo disintegrated on the motorway, leaving a large oil slick and an even larger bill.  He did admit afterwards that more regular servicing might have been a good idea after all.  Allegedly the mechanic doing the repairs on it found the air filter sucked halfway up the intake pipe, no idea how but once mended it soldiered on for a good few more months before he sold it.

[cms206]

 

 

I have a 2.3 LPT in the 940 and to be honest I wouldn't know it had a turbocharger at all, there's absolutely no feeling of boost, I assume it's very subtle and would be noticeable by its absence.

The turbo in the 2.3LPT in the 940 is VERY noticable when you're used to the 2.3 n/a in a 740; the power output is near identical (135bhp in the LPT, 131bhp in the full fat n/a 2.3i) but the LPT is a far, far torquier machine through the gears.