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Discussion Starter · #1 ·
Hi guys, just finished doing the cylinder head replacement on my 84 900 Turbo 8 Valve. I'm not sure what compression is like (Should I check this) Just going to be checking base boost and things like that over the next few days, however wanted some insight into ways to increase power a bit

Ive got a newer turbo (water cooled) Garrett in it (previous owner did this) and a 3'' turbo back exhaust (previous owner did this too, woooo :)

I was wondering what amount of boost I can safely get out of the engine as is.. its done 230 000km, is an intercooler out of a later 900 turbo a good idea for better boost? if so is there any swapover walkthroughs or threads on it?

Also i've read a lot about air/fuel ratio gauges being very important asset in T8's as they have CIS injection. What do I need for this system? do I already have an O2 sensor in my exhaust (would it be further down the exhaust as I cant see one on the manifold)? if not can I drill a hole and tap a thread or would I have to buy a different manifold with a thread for an O2 sensor?

Sorry for so many questions, thanks in advance for any help
 

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Discussion Starter · #2 ·
Also what intake setup should I use? Can I discard the airbox and use a flat panel filter K & N? or similar set up? or are the electronic componenets/sensors/units in the airbox necessary for my car engine health and running?
 

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I just installed a 16 valve intercooler system into my 8 valve turbo (N/A conversion). It definitely makes a difference as far as the temperature of the intake system as a whole. Even just touching the pipe coming directly from the turbo to the throttle on the original 8 valve system is uncomfortably hot. The pipe after the intercooler when upgraded to the 16 valve system is just warm, about like the ambient temperature under the hood, so I can only imagine that the air temperature is significantly lower.

Here's a photo of the install:


There's a bit more information on my project page, so feel free to take a look. The main thing is that you need to rotate the air cleaner housing under the fuel distributor so that you can install an intake snorkel from a 16 valve. I deleted the heater hose system (which goes to the exhaust manifold, may be different on the turbo vs. my N/A) and I moved the larger crankcase breather hose to run from the valve cover to the intake pipe that goes TO the turbo (see my thread). Normally this attaches below the fuel distributor, but once you add the newer snorkel there won't be room for it between the snorkel and the bottom of the fuel distributor. The final thing needed is a flexible/bellows type connector from a 9000. I can't remember exactly what part of the turbo piping that was, but it definitely came out of an early (pre '93) 9000 turbo and was part of the intercooler system. It may have been the part that attaches to the throttle body. This connector is the perfect size to fit over the snorkel that comes off of the fuel distributor just over the air meter and it also fits perfectly onto the 16 valve pipe that runs to the turbo. The rest of the intercooler system is as it is in the 16 valve, though you will have to just let the intercooler itself sit gently on top of the lower radiator hose, so be careful there not to pinch it off. Let me know if you need any further help.




Project thread:
http://www.saabcentral.com/forums/showthread.php?t=166078&page=4
 

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Also what intake setup should I use? Can I discard the airbox and use a flat panel filter K & N? or similar set up? or are the electronic componenets/sensors/units in the airbox necessary for my car engine health and running?
You will be stuck with the airbox as is unless you were to custom fabricate something to attach to the bottom of the air meter or completely change the fuel system to something other than the CIS it currently has. I doubt very that it will be a restriction anyways, even if you were to do some porting to the head. Without porting the head, I think that there is just no way the 8 valve engine could consume more air than you can already provide.
 

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Discussion Starter · #5 ·
awesome thanks Mmoe ill have a look into sourcing the 16v intercooler parts

So what about the O2 sensor thing... mines an 84 where abouts would the 02 sensor in the exhaust go if it is there? would it be on the manifold or further down the exhaust pipe?

I just read that if your gonna be changing boost and stuff (which i hope to do) that you should have an AF gauge to keep an eye on when the engine is leaning out (high boost /high rpm)

I have the grey box APC, how much boost can I safely get out of my engine? 13 -14psi? or leave it at 9-10psi?
 

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The 02 sensor on 16v c900's sits in the exhaust downpipe. If you look at the picture above, it would go underneath or on top of the downpipe between the two flanges directly off the turbo. So, after the turbo, but if you look where the battery heat shield ends, there's another flange, and it would sit right in there. Looks like mmoe has his right in the exhaust manifold.
 

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Discussion Starter · #7 ·
Yeah I saw that but I have an 8v I was wondering do the 8 valves have O2 sensors... I saw a page that reckoned they do, but mines not anywhere on my exhaust manifold, I just had an intense look, not to mention I replaced the cylinder head last week so I would have definately seen it if it was around there?

any other ideas?
 

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Yeah I saw that but I have an 8v I was wondering do the 8 valves have O2 sensors... I saw a page that reckoned they do, but mines not anywhere on my exhaust manifold, I just had an intense look, not to mention I replaced the cylinder head last week so I would have definately seen it if it was around there?

any other ideas?
Some of them does, some not. All US models have emission control I think, for the rest of the world it was not a must. If you don't have O2 sensor or cat, I suppose that you don't have emission control.
 

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I suppose the O2 sensor could be placed in the downpipe and I have a 16 valve downpipe with that configuration, but you would have to leave one in the manifold anyways so I figure it's best just to leave where it is. There is no way to use a 16 valve exhaust manifold, so there's nothing to change to unless you custom fabricate a new exhaust manifold. If I were custom fabricating one, I'd probably place it high up in the downtube after the downpipe/elbow that comes off of the turbo, mostly just to get a straight shot of wire from there to the connector. The current configuration definitely puts some stress on the wire since the plug is kinda pointing in the wrong direction as that goes.

Overall, I think a performance build really has to start at the head. Porting both the intake and exhaust along with potentially some changes to the valvetrain (stiffer springs?) would likely be a prerequisite to boosting at higher levels. There were also some older model years with really low compression pistons (I think something like 7.5:1?), so taking a bit further to a block build would also offer much more possibilities for boosting. For high levels of boost, you'd want low compression and good airflow. Then you'd start needing to monitor the fueling and make modifications there.

Personally, I plan to modify the engine to run on T5, but for different reasons than you might. I simply won't be able to boost over maybe 10psi as an absolute max since I have a high compression engine, but I'm not looking for a high performance engine, just a very peppy daily driver that can tackle passes with lots of weight in the trunk! I'd suggest that you start looking into this as an option for fuel and boost control. It will require modifications to the intake, but if you're porting, etc, then it won't be that big of a deal to make those modifications. There are ways to get more out of the CIS that you have, but I'm not really a tuning expert on CIS and can't help you much there. I'm usually just happy when my CIS is actually working properly. ;)
 

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Discussion Starter · #10 ·
Yeah ok, so your saying its not really safe to push the boost up a little bit from its 8psi to 10 or 12 psi without doing head modifications?

Yeah well Is it easy to just tap a thread into the exhaust manifold for a wide band O2 sensor and run a good air fuel ratio gauge in the cabin so u can see how the CIS is working with upped boost?

I guess ill intercool my turbo thatll give a bit more kick yeah? I dont wanna turn it into a race car either, just a nice daily driver thats fun
 
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