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AznDrgn  
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PostPosted: Fri Mar 15, 2002 10:04 am    Post subject: Reply with quote

I didn't really care too much about the turbo itself all I really wanted was the manifold. If I had gotten that I figured I could find another turbo to bolt onto it. The bidding at the end was insane, it was at $91 2 hours earlier and I came to check and it was at $305 30 min to the end. Oh well I guess I'll just find some other way of getting a turbo onto there.
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Cbass  
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PostPosted: Fri Mar 15, 2002 10:05 pm    Post subject: Reply with quote

So rick, what actually blew on the motor? It's often really easy to turbo a motor, but who knows how long it'll last?
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Rick MacLaren  
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PostPosted: Sat Mar 16, 2002 12:44 am    Post subject: Reply with quote

What blew the motor?

Short answer: Impatience and an old engine.

Just a bit of history: I went to a mechanic here in Waterloo TWICE for him to find an oil leak. He failed and charged around $2000 CDN. After his failure to find the leak, the engine blew within a week.

My Toronto mechanic, who apprenticed at VW Germany, and is a pretty patient guy, went over the ruins while collecting pipes and crap to put on the new rebuilt motor. I'm putting the blown one in a guest room as either a memorial/shrine or I'll rebuild it.

My Toronto mechanic guy found a number of things that the Waterloo mechanic guy missed, each of which he felt contributed to the blown motor:

1. A blown turbo gasket which caused the pop-off valve to malfunction causing bad things to happen (Techie Talk)
2. Two pinhole oil line leaks
3. One pinhole air line leak
4. One 0.2 bar spacer that some YaHoo put in the wastegate (sheepish grin) didn't help any.
5. A piston ring that disintegrated into pieces.
6. A driver that reached top speed in 4th, but left the engine running too long in 4th at max'd RPM's without any acceleration before shifting into 5th, thus overtaxing the engine.

Recall that I was driving on the 427 playing around with a Mitsibushi 3000 GT...(winning too!)...

On seeing the loss of oil from the popoff, the driver (me) rapidly removed his foot from the gas at around 220 KPH. This, combined with oil loss, the heat and pressure built up from going so fast so quickly, caused excessive stress on the now less lubricated rod bearing and piston ring. A piece of the piston then hit the spark plug, or came between the piston and the plug, destroying each, and sending pieces of the piston, ring and other junk around the engine, destroying the whole thing. Total cost? $8000.00

Conclusion: Two primary factors - Heat and oil loss - and poor owner judgement, blewd up da car.

CBASS: Agreed. It's really easy to turbo a motor. My feeling, for what it's worth, is that you should give whatever engine you're gonna use a good rebuild and make it strong first. Once it's strong, (i.e., everything new inside, and like Vaughan says, treated or coated, shotpeened, whatever, that you can afford) then make it fast. Doing it this way will cost less. Doing it fast first, on these old parts, will likely backfire.


[ This Message was edited by: Rick MacLaren on 2002-03-16 00:55 ]
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Cbass  
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PostPosted: Sat Mar 16, 2002 9:07 pm    Post subject: Reply with quote

Ah yes. The classic turbo a tired engine story. Very close to the nitrous boost the tired engine story.

I like to break down turbocharging into two categories. Turbocharging jobs you want to last, and turbocharging jobs you want to sell.
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Rick MacLaren  
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PostPosted: Sun Mar 17, 2002 9:00 am    Post subject: Reply with quote

Yeah I think I'm a victim of the 'turbo job you want to sell'...

I remember even when test driving the car before I bought it, I could hear a slight knock when I max'd the boost (7 PSI) and it was a deep knock sound. That was probably a rod bearing or other problem already present in the system.
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Cbass  
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PostPosted: Sun Mar 17, 2002 10:06 pm    Post subject: Reply with quote

It happens. No way of telling unless you tear it down either. This is why whether it's a swap or a custom turbo, start with a low mileage engine!
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AznDrgn  
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PostPosted: Tue Mar 26, 2002 4:25 pm    Post subject: Reply with quote

Quote:

On 2002-03-15 04:20, jamez wrote:
get the SDS fuel injection/engine management system, it comes with a knock sensor, it will also retard timing, man it does everything..


Where can i get more info on this SDS system?
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Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2740
Location: Sydney, Australia

PostPosted: Tue Mar 26, 2002 4:53 pm    Post subject: Reply with quote

have you tried their web site http://www.sdsefi.com/
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Cbass  
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PostPosted: Tue Mar 26, 2002 6:17 pm    Post subject: Reply with quote

I'm partial to the Motec M48 system myself. Everything from fuel and ignition curves to boost control and traction control.
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Rick MacLaren  
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PostPosted: Wed Mar 27, 2002 1:52 am    Post subject: Reply with quote

Your ears are the best knock sensor you can buy...all it does is detect sound, and typically that is after it is too late!
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AznDrgn  
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PostPosted: Wed Mar 27, 2002 5:15 am    Post subject: Reply with quote

Looking at all these engine management systems they all can control the fuel injectors and fuel maps. My question is how does this work with our fuel systems. My understanding is that our fuel is controlled by the airflow sensor plate in the intake box. This is completely mechanical and has no electrical controls so how would an engine management system get control of this??

Rick if I got a management system with a knock sensor in it wouldn't that help since the system should be able to retard timing if knock starts to occur?
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Rick MacLaren  
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PostPosted: Wed Mar 27, 2002 8:32 am    Post subject: Reply with quote

The knock sensor on most any car is just a microphone-type device that detects sound. The APEXI unit is about the best EMS and knock sensing system...but the problem with most any engine management system that you or I can afford is that either:

(a) They're built to run with your existing EMS so that timing can be retarded along with any knock - problem is, this requires a knock sensor and the appropriate switching. Our 924's do not have this capability built in.
(b) An EMS with a knock sensor is frightfully expensive. And you'll have to install the knock sensor. Then you'll have to install the EMS. Have you ever installed an EMS? What will your mechanic charge you to install a sophisticated EMS? My bet is that you'd better put about $2000 USD aside just for a decent EMS and installation. If you do it yourself, check out Rennlist and see the WIRE MESS that you'll be getting into with an installation like that. Once you're done, remember, knock sensors can be thrown off by other sounds like
(i) Timing chains (i.e., on old V8's)
(ii) Bad motor mounts vibrating
(iii) Anything else that vibrates or knocks.

Heres a guy whose installed an EMS himself into a 944 turbo, and remember, this car was equipped already with a digital ignition, so the wiring here is MINIMAL compared with what you'll have to do for the 924:



Now, here is the kind of electronic and mechanical complexity you face in using an advanced EMS to control your system:

http://www.virgeweb.com/rage2/944t/2002-02%20rage2_sdsmap.XLS

Once installed, typically, the knock sensor and gauge is simple a doo dad that guys can look at and enjoy, but it's not terribly functional. Now, if this thing is rigged into your EMS to retard timing, then what about false alarms? Let's say your engine moves a bit and makes a knock from a bad motor mount, now your knock sensor is gonna pick that sound up and retard your timing. This will be highly undesirable. And from the guys in the Grand National community I've spoken with, you will get ignition blips from just normal engine noise. For example, what if your engine has a bad tappet? That loud tappet can also set off a knock sensor and again, retard your timing.

In my view, your rebuild efforts are worthwhile, but the approach you're taking is that you can do all of this with a stock 924. The fact is that although it's been done, you're going to spend WAY more on an EMS, weak turbo, plumbing, intercooler, than you'd spend getting the proper pistons and engine rebuild that a turbocharger requires. Why not just soup up the 924?

Bottom line? EMS, turbo, plumbing, fuel rail, distributorless ignition other misc add ons...

$4000 USD minimum plus a whack of expertise - that can come from you, or from your mechanic. If it comes from your mechanic, multiply that figure by 1.5. And my feeling is that if you have to ask questions about how to do it here, on this site, then you're in need of a very knowledgeable mechanic, and thus, you're in for about $6000 USD in modifications.


[ This Message was edited by: Rick MacLaren on 2002-03-28 02:20 ]
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Cbass  
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PostPosted: Wed Mar 27, 2002 10:37 am    Post subject: Reply with quote

Azn, it's best to go to a new fuel rail, with electronically controlled injectors, which gives the stand alone ECU the room to work. These systems really shine on newer engines, with distributerless ignition and EFI.

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AznDrgn  
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PostPosted: Thu Mar 28, 2002 7:40 am    Post subject: Reply with quote

Well... with all that said and my new understanding of the work that needs to be done I think I'll put that off for a long time. In the mean time I think I'll just go with a car that is already turbo charged.

Thanks for all the help
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Rick MacLaren  
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PostPosted: Fri Mar 29, 2002 12:50 am    Post subject: Reply with quote

Dwak has a couple he wants to get rid of...and he's Canadian so your dollar will go far. Good luck!
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