Saab Turbo on 4.0

[BADaXJ]

i got a question... one of my friends just blew the engine in his turbo saab. i don't know much about turbos and non-jeep engines but would it be worth my time to ask him if i could have the turbo out of it and retro fit it to my xj or mj? i know anything is possible with enough money and time/ skills but do you think this could be a worthwhile project? i'd probably have to get new injectors and do some computer stuff too right?
Thanks

 

[94XJ2door5speed]

They are very tiny turbos. You need to find out 2 things about the turbo first; 1. The max boost before the built in waste gate opens. 2. You need a compressor map of the turbo. This shows its optimum performance zone to put it in lamens terms. This "map" will show its spool characteristics and it is used to determine if your engine will over or under work the turbo. All turbos have an optimum performance and saturation "field" if you wanna call it that. A 4.0 may cause the turbo to meet max boost and its optimum performance range at a very low rpm driving it into its saturation field and eventually melting the turbo as your motor meets its optimum rpm range. I did all the math on my ford 4.9l inline 6 and it needed a T3/T4 hybrid or larger. And just for a comparison i used a saab turbo on my 25hp twin cylinder briggs and straton back when i was racing lawnmowers and it spooled it so theres some food for thought.

 

[bcmaxx]

Often enough if you have engine damage in a turbocharged engine the turbo is also damaged as the oil that enters the turbocharger is contaminated with metal. We see this in turbo'ed boxers that are blown.
For warranty purposes the manufacturer requires we send in the hard oil lines,untouched and uncleaned for analysis

 

[alex22]

How many miles are on your engine? Boosting an old engine usually results in alot of ring blow by. The turbo was built for a 4 banger (2.0L?) which means that it will have a much larger volume of air moving through it. Since the turbo will have to spin faster than intended the oil will get hoter.
I also thought about turboing my 4.0 but here is the list of things I either did not have the money for or ability to make.
The master cyl is a vacume booster, would either need a a vacuume pump or a standard cyl.
The stock header, or an aftermarket header would not hold up well to the extreme temperaure and the weight of the turbo hanging off of the end might bend the soft pipes.
The headers have long primaries which would lead to turbo lag.
Depending on the amount of boost you might not have enough pressure in the fuel rail, requireing either a new rail or pump and large injecotrs.
Eventually you will need a timing computer to retard the timing as you boost.
Not trying to piss in you're cheerois, just leting you know why I gave up.
If you search youtube for "Turbo XJ" there is a vid or two of an italian who used a Maserati turbo in his XJ. His website is www.toch.it but it is under construction and I could not find any place to send an email to him to ask about how he did it.

~Alex