High mileage turbo

[Paul Fraser]

What are the likely problems with a high mileage (180-200k) mid eighties 944 turbo? I've had a couple of old 944s so I have some idea of the general problems, but what specifically happens to the turbo part of the engine at these mileages? What parts are there? What parts wear? Does the engine get cooked by the the turbo shoving all that extra fuel and air in? As you can tell from the latter I haven't had a forced induction car. Yet.

 

[Fen]

The turbo might well be on the way out as that is quite a good mileage for them. You'd also likely find sundry vacuum leaks etc. as the pipes have got brittle over the years and Turbos are worse through having more of them as well as making the intake side of the engine where they all live hot as well as the exhaust side. Aside from that the only Turbo-specific issue I can think of is the wastegate which will at best be weak and could well be cracked causing it to stick either open (poor performace) or closed (way-hey performance until the knock sensor spoils the fun, but at least it won't blow up).

Head gaskets on Turbos are a bit more likely to fail than NA cars, especially if the boost is played with (and there's no point buying one to keep standard as the NA cars drive much better and an S2 is just as quick real-world as a standard Turbo), otherwise it's all the usual corrosion of the sills, brake calliper plate lift, failed engine mount, clutch (more expensive labour to replace on a Turbo, especially an early one, due to the crossover pipe) etc. that you probably already know about.

 

[John Sims]

I read somewhere that after 160K the Turbo is on borrowed time and should be replaced.....well that was my excuse [8D]

 

[Paul Fraser]

Thanks to both of you for your replies. How much for a new (or is it worth getting secondhand/recon?) turbo, wastegate? How much for a new engine gasket fitted?

 

[Fen]

As a guide I have a turbo in the garage with 3,500 miles since a rebuild. £300 would part me from it. I'm not sure the labour on a head gasket, but parts are in the £100 - £150 range I'd guess (gasket set, studs). Probably it would be worth having the head refurbed while it's off though. Wastegates are scary expensive new, but a used one is worth about £100, or a much better aftermarket one could be on the car for £500 all-in with a noticeable performance gain to be had. That's usually the first or second step on the slippery slope for most people.

 

[sawood12]

Head gasket will cost you about 10 hrs of labour at anywhere between £30-£60 per hour and be prepared for unexpected costs that might crop up once the head is off e.g. corrosion that needs skimming. A 2nd hand turbo will cost you circa £300 (I think a new one is around £1300) and a wastegate will cost you anywhere between £400 and £600 for a dual port not single port as any 2nd hand single port wastegate you might find will almost probably be equally as cream crackered as the one you're taking off and brand new ones are about £1k. I got a dual port wastegate that was modified from a standard item and you exchanged with your old one. When I took my wastegate off the casting was completely cracked so I didn't get my core charge back which was worth $300!!

 

[Diver944]

To be honest we don't really hear of that many turbochargers wearing out or failing and similarly we normally only hear of head gaskets going once the car has been modified in some way. The standard wastegate is very poor though (even when new) and you will be losing boost so I would definitely budget to get an aftermarket one asap.

A good mechanic who know's our cars could tell you a lot about the condition of the turbocharger just by pulling the intercooler pipe off and giving the turbine a 'wiggle' []

After saying all that it could be a wise move to change the head gasket once any increase in boost is made (and if you do it at the same time as fitting a new turbocharger then the intake manifold will already be off so the labour will scale down a bit)

 

[Paul Fraser]

What is the opinion on this one?
http://www.paragon-products.com/product_p/951-cg-02.htm
Is there a UK source for this or something similar?
I assume this wouldn't cause any insurance alteration?
What is the difference between this and a 'dual port' wastegate. Why does this latter require a boost controller? I assume a BC adds a level of complexity to things and needs to be wired into the cabin?
Sorry for all the questions but I am quite ignorant about 944 turbos beyond knowing that there is an element of undesirable lag in the spool up.

 

[Fen]

I don't know anyone who has that one, but it does seem that maybe it could be considered not to be a modification. That being the case it will almost certainly suffer the same poor design as the original.

I posted something about the differences between the standard and DPW recently, I think in the Electronic Boost Controllers thread, so you might want to search for that.

I'm serious when I say that if you don't want to modify it, don't buy a Turbo as a well specced S2 will be a better car for you.

 

[sawood12]

The Lindsay racing clubgate in your link is modified from a standard Porsche item and has the diaphram element replaced with the Linday Racing manufactured one which is supposed to be better and more robust than the standard Porsche set up. The clubgate is meant to be a straight replacement with the single port Porsche item and is allowed in the 944 turbo race series. Be wary that the one you remove from your car may have the cast body cracked like mine which means you'll loose your core charge as they wont accept your wastegate in exchange. I got the Lindsay Racing dual port wastegate. I doubt that any single port wastegate will be any good as it is balancing the boost pressure against a spring an the problem with a spring is that even a small force against it results in a compression of the spring which means the wastegate could crack open slightly and bleed exhause pressure resulting in increased lag. A dual port wastegate balances the boost pressure on one side of a diaphram against another boost pressure signal that is controlled by a boost controller to a set boost level. This means the wastegate will remain firmly shut and sealed until the boost pressure achieves the level of boost you set on the boost controller. A dual port wastegate is the way to go in my opinion and as far as boost control the Manual Boost Control valve works well even if it isn't as elegent or flexible as the much more expensive electronic boost controllers. My car is essentially standard apart from a Dual Port Wastegate and a Manual Boost Controller and I recently got 240bhp at the last Weltmiester rolling road so a good wastegate is worth at least 20bhp. Dont look at this as a modification - it's getting your engine back to how it should have been from stock if Porsche fitted a half decent wastegate.

Fen is right in what he said about modifying a turbo and it's a personal thing as to what you want out of the car. I personally like the exhilaration of the boost kicking in and even though an S2 is just as quick in the real world I can't imagine one putting a smile on my face in the same way my turbo does - some people like the smooth progressive power delivery of an S2 or N/A 944, others (like me) like the sheer kick in the back that only a turbocharger can provide. I never got into 944 ownership with the intention of getting into modifying the car but I am being sucked into the whole world and my wishlist is adding up!!

 

[Paul Fraser]

This was the one I was daydreaming over:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=4646469492&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

Gone, gone gone....
Oh well, I'll know more about them next time around.

 

[Fen]

It hasn't gone; it didn't make reserve. One of my mates pointed it out to me as a breaker to rob it of engine parts from, but I forgot to look at it.

 

[Paul Fraser]

"The seller ended this listing early because the item is no longer available for sale." alas.
Wouldn't have thought it would have been worth breaking for engine bits due to age and mileage of motor. Bodywork and interior looked very nice though, which was partially what attracted me. You wouldn't break something as nice looking as that would you?

 

[Fen]

Ahh, missed that. "The seller ended the auction early because he bottled it as the car was giung too cheap" probably.

 

[Paul Fraser]

Probably not. At one point the bid was £2050 and he reduced the reserve to £2051. I think he wanted to shift it.