Warming up an old Saab Turbo?
Discussion
I've just bought a classic 'full fat' Saab Turbo. It's got a fairly substantial mileage on it, and having never owned a turbo'd petrol car before, I'm a bit unsure about warming up/cooling down and the consequences in a rather tired 30 year old car that was (in it's day) a fairly high performance model.
With other older cars I've always tried to give them 2 minutes between firing up and moving to let oil circulate and the block warm, but with the older generation of turbos I've been told that 5 minutes before putting any load on the engine is preferable and it absolutely must be left to idle for at least 2 minutes after a run before switching off to allow oil to circulate through the turbo and cool it down.
I am finding this a royal pain in the arse, particularly when doing a series of short runs, such as going to the shops, getting petrol etc.
Will I knacker the turbo if I shut it off without cooling down? Does this apply if the turbo hasn't been running on boost (ie <2,500rpm)?
What is the advice of the PH experts?
With other older cars I've always tried to give them 2 minutes between firing up and moving to let oil circulate and the block warm, but with the older generation of turbos I've been told that 5 minutes before putting any load on the engine is preferable and it absolutely must be left to idle for at least 2 minutes after a run before switching off to allow oil to circulate through the turbo and cool it down.
I am finding this a royal pain in the arse, particularly when doing a series of short runs, such as going to the shops, getting petrol etc.
Will I knacker the turbo if I shut it off without cooling down? Does this apply if the turbo hasn't been running on boost (ie <2,500rpm)?
What is the advice of the PH experts?
Thanks for the replies!
To answer some of the points above:
No handbook - it's had several owners and is ticking towards 200,000 miles! The body is in superb condition with no rust and all original panels, original tool kit etc. but it's showing signs of wear on all the bits that tire with age - moving parts and electrics.
The car was previously owned by a truck engineer who strongly emphasised the need to warm/cool the engine to minimise wear on the turbo when I bought it.
The engine needs a bit of work anyway (valve guides are tired so it smokes like a mofo if left standing for a few days and then started) but I'm going to try to put that off for a while and get the interior and electrics all sorted first. So far I've been replacing various relays, pumps and switches, with a replacement dash coming soon.
I'm just a bit more cautious with the turbo because it's an additional complication that I'm not too familiar with and expensive if it goes wrong!
But I do love getting it on boost in 3rd gear on a country road and shouting TUUUUUURBO a la Clarkson
To answer some of the points above:
No handbook - it's had several owners and is ticking towards 200,000 miles! The body is in superb condition with no rust and all original panels, original tool kit etc. but it's showing signs of wear on all the bits that tire with age - moving parts and electrics.
The car was previously owned by a truck engineer who strongly emphasised the need to warm/cool the engine to minimise wear on the turbo when I bought it.
The engine needs a bit of work anyway (valve guides are tired so it smokes like a mofo if left standing for a few days and then started) but I'm going to try to put that off for a while and get the interior and electrics all sorted first. So far I've been replacing various relays, pumps and switches, with a replacement dash coming soon.
I'm just a bit more cautious with the turbo because it's an additional complication that I'm not too familiar with and expensive if it goes wrong!
But I do love getting it on boost in 3rd gear on a country road and shouting TUUUUUURBO a la Clarkson
NiceCupOfTea said:
What year is it? Iirc the earlier cars had oil cooled garrets which needed a bit more care than the later smoother water cooled Mitsubishis. Either way, just drive gently until fluids are warm and a gentle last couple of minutes before switching off.
My 91 is on 190k on the original turbo.
Enjoy - pics?
It's an 88 model, so I believe it is a w/c turbo that's fitted. My 91 is on 190k on the original turbo.
Enjoy - pics?
Some pics and a proper write up will follow just as soon as I've got some free time - various work related stuff is taking priority at present. I've been meaning to spend a morning detailing it properly, but I've been flat out for the last month. Whilst writing this I realised that I've done less than 200 miles in it since getting it back in early February! Shocking!
Olivera said:
I don't quite understand why you are so concerned with the turbo but not with worn valve guides. A refurbished, second hand or replacement turbo is likely to be much cheaper than your impending cylinder head rebuild.
I've already factored in the work needed to the head, and am planning to upgrade to a cylinder head from a 2.1 engine - here's some info on 900 turbo engine upgrades. I've already sourced one from a low mileage car! The worn valve guides are a 'slow burn' issue, in that they won't cause the car to stop working tomorrow. Cooking the turbo bearings on the other hand...
I'm not sure how long I'll keep the car for, and the high mileage means that, even if I got it back to tip-top condition I'd not get big money for it. As such, I'm planning to improve the car where I can if it doesn't cost too much money, but keen to avoid additional expense/wear if at all possible.
Isn't it always better to be mechanically sympathetic and minimise unnecessary wear on engines?
For posters here and elsewhere saying idling an engine until it's warm is unnecessary, I'm a bit confused by this: I started my motoring life in old Triumphs, which suffer terribly from oil starvation, and used to sail boats with old-school Gardner diesel engines. I had it drilled into me at a young age (and this could be completely wrong) that putting a load on a cold engine increased wear because everything was 'tight' and lubricants more viscous, so reducing lubrication and increasing wear.
All I can go on is personal experience here because I'm not a mechanical engineer, but I've managed to nurse worn Triumph engines for 50k+ without a rebuild (I've also never had to change a clutch!) so the advice I was given back in the day seems to have worked for me up to now. That's not to say it's right; merely an observation.
Any mechanical engineers care to comment?
Here's a pic of my car with an exceptionally rare and very tidy Mk1 Sunbeam Alpine
All I can go on is personal experience here because I'm not a mechanical engineer, but I've managed to nurse worn Triumph engines for 50k+ without a rebuild (I've also never had to change a clutch!) so the advice I was given back in the day seems to have worked for me up to now. That's not to say it's right; merely an observation.
Any mechanical engineers care to comment?
Here's a pic of my car with an exceptionally rare and very tidy Mk1 Sunbeam Alpine
NiceCupOfTea said:
What year is it? Iirc the earlier cars had oil cooled garrets which needed a bit more care than the later smoother water cooled Mitsubishis. Either way, just drive gently until fluids are warm and a gentle last couple of minutes before switching off.
My 91 is on 190k on the original turbo.
Enjoy - pics?
A full write up is in progress; Part 1 here - Saab 900 Turbo ConvertibleMy 91 is on 190k on the original turbo.
Enjoy - pics?
aeropilot said:
spitsfire said:
I'm not sure how long I'll keep the car for, and the high mileage means that, even if I got it back to tip-top condition I'd not get big money for it.
200k isn't high mileage for a C900 
It's just about run-in
I've posted up the 'to do' list (first instalment) over on Readers' cars; I'd be grateful for any advice/words of warning from Saab owners
DKS said:
Is your rear beam a mess? I'm just in the process of fitting a powder coated one with new bushes. Very satisfying.
I haven't looked at the rear beam yet, but I'd guess that it is original so probably needs an overhaul/rebush/replaced. My attempts to test the suspension with hard cornering have been pretty fruitless - it seems (although harder to tell with a rag-top) fairly neutral, and lets go quite progressively. I have been amazed by just how sticky the front is, even on mini roundabouts. Are there any easy ways to check the health of the rear beam?
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