Turbo Buying Advice

[Guest]

Hi All - I'm a prospective 924 Turbo owner after a bit of advice on this particular model. I owned a '91 928 GT until recently, but 'family financial pressures' (3 young kids) have forced me to sell it. I'm hoping the Turbo will still give me some thrills even if I've been used to a 5L V8 []

But - after a little research & viewing a few cars I've realised how 'fragile' these cars seem to be. One car I viewed had already had a new engine, and a separate head rebuild/new valves 40K later, with a total mileage of just over 100K. Another had its head rebuilt 30K miles ago, but seemed sluggish on turbo-boost - when I measured the power output (with one of those little g-meter gadgets) it showed only 115bhp - i.e. below that of a non-turbo 2L 924!
One major difference between these 2 cars was that there was no noise from the turbo on the low-performance car, but the 'good' car (I didn't measure its output) exhibited a noticeable turbo-whine/whistle whenever the turbine started to spool up (from 2K revs). Can any Turbo owners tell me what I should hear?
[I'm guessing that the bad car had a 'dead' turbo, & the good car possibly has issues with the turbo bearings]
In the past I've owned a Lancia Delta Turbo & a Saab 900 Turbo but I can't remember their "noises" [8|]

This is all besides the 'normal' 924 issues with cracked dash, split seats, holes in battery tray, hatch leaks & other ravages of 24-25 years. Any other buying advice welcome!

 

[John Sims]

Hi Scotchw,

Why a 924 Turbo not a 944 Turbo? The later model was more advanced, more powerful and is more plentiful. Granted a 924 Turbo may be cheaper to purchase but could end up being more expensive to get to a reasonable and reliable state. Just a thought.

 

[usermjg]

I have quite a buyers list of things to look out for when buying a 924, if you e-mail me i will e-mail you the file back as its quite a read, and covers all the 924 models.

However have you thought about the 924S an E plater is 160bhp, not quite the 170 or 177bhp of a turbo but a lot of grunt from the 2.5 litre engine, and with a little modding here and there im sure the engine could put out a few more bhps. My car is a 1986/ Creg and the engine is as sweet as a nut, pulling and running strong, so if nothing else have a test drive in one.

Marc

 

[John Sims]

ORIGINAL: usermjg

However have you thought about the 924S an E plater is 160bhp..........

Marc

We had a 924S on last weeks Scotland Tour and that thing flew. There were very few times when even the 944 Turbos had to wait for it.

The 944 Turbo has awesome power but has lag and brutal power delivery, so care is required when deploying the compressed horses on the twisty bits. The 924S (and 944 Lux) has less overall power but what power is available can be exploited far earlier due to its linear delivery. I might be so bold as to suggest a 924 Turbo is the worst of both worlds.

 

[Guest]

ORIGINAL: John Sims


Why a 924 Turbo not a 944 Turbo?

Thanks for the idea John... but I had to sell my 928 for financial reasons - hence my budget is limited this time & won't stretch to a 944T.

 

[924nutter]

With a power to weight ratio of 227 bhp per tonne you are going to notice dropping down to 161 per tonne. That said my 931 is more nimble than my 928 s4, and more economical. Just! There is good and bad in every model, and the 931 is no exception. Go for a low milage model if your budget runs to £4500. I know of one on ebay that ought to go for about £4200 and one in Auto trader that had been for sale for a year and had the price dropped from £4995 to £4500 so you might be able to knock a bit more off. The crank in a 924 is nitrided ( or tuftrided can't remember) and consequently wear very little. With the 924t more than any other a good service history is parmount for the much needed regular oil changes. The turbo (931) valves are made from suitable steels for the heat involved, and this is the reason why they are dearer than the 924 valves. A number of 931 owners are guilty of switching the engine off at the end of a run whilst there is a lot of residual heat left in the turbo instead of letting it simmer on tick over for a good minute, and this cooks the oil. This can carbonise and restrict the oilways leading to premature failure of the turbo. The turbo needs 98 ron petrol minimum and this is generally unavailable so some pinking can occur if it has been run on 97ron. In my area I can get Bayfords 99 ron , and I run on a mixture of £25 of 97ron topped up to a full tank with 99 ron. All I can say in conclusion is that I have used a 931 as a daily run-about for over a year with no complaints, and anyone who has seen me driving back from Cornbury house knows that I do not cosset my car.

 

[924nutter]

Certainly, John, the 170 horse power 931's power delivery was a bit like a switch on achieving 3000 rpm, due to the lower compression ration and higher boost.( 7.5:1 and 0.7 bar) which gave great torque and a better 0-60 time, but the 177 horse power version is way more refined with a higher initial c/r of 8.5:1, and 0.6 bar of boost giving slightly lower torque and a 0-60 time of 0.6 seconds slower. I have never noticed really non linear power deliver when coming out of a bend flat in second in mine, and I am not going to trade insults with you about which car has the most pleasing shape, because obviously the 924 wins hands down. They had to take 13 bhp off the 924s to stop it being faster than the 944. Thank goodness they didn't see fit to make a 924s turbo with 250 brake.

 

[Guest]

ORIGINAL: usermjg

However have you thought about the 924S an E plater is 160bhp, not quite the 170 or 177bhp of a turbo but a lot of grunt from the 2.5 litre engine,
Marc

Yes - I did consider the 924S... but my economy-oriented thinking figured that the running costs of the 924S engine would be higher than those of the old VW/Audi unit. The 'S' engine is kind of 1/2 the 928 unit, with all the associated costs of a "pure Porsche" engine. Agreed that some of the 924T components are uprated from the 924 'plain', but the 924T engine is still simpler than the 924S unit. And truth be told, I quite like the idea of returning to owning/driving a turbo-charged car.
Cheers, Scott.

 

[Guest]

ORIGINAL: 924nutter

Go for a low milage model if your budget runs to £4500. >>>
All I can say in conclusion is that I have used a 931 as a daily run-about for over a year with no complaints, and anyone who has seen me driving back from Cornbury house knows that I do not cosset my car.

Well - here's the crunch. I also intend to put the car into daily use for my 50 mile round-trip motorway commute - and my faith in Porsche engineering says that even a 1980/81/82 Porsche can do this. But, I am looking at spending nearer the £2K mark. I've already viewed a few cars around this price point. Obviously they aren't concours condition, but I'm not so worried about that - I can do a bit of remedial work on paint/body/interior if necessary - but I do want reliable mechanicals (engine/gearbox).
So am I dreaming? I think its possible...

 

[924nutter]

Looking at prices, which I do regularly, I would say that a usable 931 should just about be doable. You would obviously want to go for one which only needed tlc on the body work, as you say. Could you squeeze another £500. You would have a wider choice, and in the long run end up paying less, but you will still have to be patient to get the right car at the right price, in my opinion, but what do I know?

 

[924nutter]

By the way I have a 52 mile round trip to work, some dual carriageway, some motorway depending on the route I take. I get about 22 to the gallon. Better fuel economy if I stay between 2900 and 3100 rpm. With 16" Boxster S wheel that's quick enough.

 

[Guest]

ORIGINAL: 924nutter
By the way I have a 52 mile round trip to work, >> I get about 22 to the gallon.

Glad to hear that the car copes happily with that commute. Is your 931 an S1 or an S2? 22mpg sounds on the low side compared to the book figures, although there was an increase in mpg for the S2. Or do you just love the sound of that turbo spinning up all the time, & can't resist being heavy with the right foot []
BTW - do you hear any whistle/whine at all from your turbo?

 

[924nutter]

Right foot 2.5lbs of pure lead. Turbo whistles a treat. E mail me, I have an idea.

 

[Guest]

Now here's an unusual one for the model/option experts - I viewed an '82 Turbo that had manual windows & sunroof, and was first registered "overseas" (although it was subsequently registered in UK within 4 months). The car is RHD. Now I thought all 924's post-80-ish were sold in UK with "Lux" pack (elec windows etc.), and certainly elec windows would be std for a Turbo. Any ideas why this turbo has manual windows, & where it might have spent the first few months of its life? It has a 'C' date code in the VIN (WPOZZZ93ZCN1..) so was definitely manufactured after Sept '81. What other options might be missing?