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I have recently purchased a 1984 900 16v Turbo which is reletiveley standard....It has an old sports exhaust, one of early twin flare types and sports shocks of some kind however I'm interested in improving engine performance. How easy is it to control the APC to increase turbo boost? Keeping in mind the engine is standard is this advisable? Whould a dump valve increase noticable power? I'm a complete new comer to Turbo engines and any info would be great.
 

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coco said:
I have recently purchased a 1984 900 16v Turbo which is reletiveley standard....It has an old sports exhaust, one of early twin flare types and sports shocks of some kind however I'm interested in improving engine performance. How easy is it to control the APC to increase turbo boost? Keeping in mind the engine is standard is this advisable? Whould a dump valve increase noticable power? I'm a complete new comer to Turbo engines and any info would be great.
Hey welcome TSL!

On the turbo engines you can block the waste gate with a ball bearing and get 14 PSI (also know as boost.)



Take some Needle nose plyers and pull the tube on the right off the APC controller. One of my friends had a ball baring laying around, you might be able to find a ball baring at a hardware or an automotive store.

Once you have taken the hose off, take the ball baring and place it in the tube to block off the waste gate, and then place the tube back on the APC, this will increase your boost from 8 to 14 psi. But the only draw back to doing this is blowing a piston. On your tack, you need to watch your APC controller, make sure when you turbo your car that the needle doesn't fall into the red, this will fry a piston.



There are plenty of other upgrades you can do to your engine as well. Full catback exhaust helps out alot. You can also get a short air filter and place it on the end of the airmass meter.



Upgrading the APC box. http://www.group9performance.com You can purchase one at that web site. This site also carrys other turbo parts like, HyperBoost Turbo Bypass Valves, bypass valves, blow off valves, and i think bigger turbos, but you have to send in your old one.



If you have any other questions let me know
 

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Well I would have to recommend against this blocking off the waste gate controller with a ball bearing. For all intents and purposes, this would disable the APC's proper functioning. Getting the best performance is easy though. The #1 step is to set your base boost properly. I can not tell you how many saabs I have seen that have poor performance simply because their base boost is set flat out wrong. Sometimes it's so bad you can hear the waste gate jingling at idle because it's not closed all the way! Base boost on US model cars should be set at 5.2. you will need a calibrated boost gauge to take accurate readings. I won't tell if you don't, but to get the maximum performance out of the car, setting the base boost at 6 PSI is safe, however it's a violation of the clean air act... having said that, set it at 6. ;) You set the base boost by un hooking the APC, driving the car and setting the waste gate rod until you have found the proper setting. After base boost is set correctly, you will find that the car will boost 12 PSI (at it should) on a stock APC. it will however taper, and that's where this comes in. Go here-- http://www.900aero.com/ And check out the APC mods section. People who have done these mods (including me) get a reliable and flat steady 18 PSI to redline out of their cars. On a side note, your 84 is going to have the old style APC which less if known about. also, are you SURE that 84 is not an 8V-T? if it is, then it has that un godly K-jectronic mec. fuel injection... that combined with boosting high will = a blown engine, so be careful... You can turn those up a bit and get less taper out of them, but once the flap in the MAM is "maxed" the engine will start to lean out and bad things will follow.
 

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Discussion Starter · #4 ·
Thanks for the useful tips...... :D

The car is a 16v version, 1984 A reg..... I believe it must be one of the first 16v turbos released in the UK . Its got 153k on the clock and seems to have been very well maintained. Say I had £400 to 500 to spend on power upgrades what would you recommend? Is it worth taking it to Abbots Racing to get a professional job done or can these mods be done DIY?

Thanks again.
 

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ALL can be do it yourself if you have the time patients and skill. Some things you should just buy and install yourself. I know DeLorean will be marketing a few custom upgrades shortly once he finalizes the testing and safety of them. (APC BOX... way better then Group9 ;)) i have one of his and it's more then enough, and it's only a light versions of his box's. If you can do the basics on a car, you can probably do most of these mods yourself. A GOOD APC will run you about $100-$300 USD easy, but well worth it for a 16V. Also you'd want a 3.0 BAR fuel pressure unit to match (about $50 USD) those are your top 2 mods next to guttin the trash can style air box and installing a air cone. With those mods in place you'll be able to rip along at very high speeds and still maintain control, and know things are fine, specially if you get a AFR gauge.
 

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I am curious about your car coco... i want to see pics! By the twin exhaust, do you mean, like the carlsson exhaust?

here is a carlsson pic:

 

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Discussion Starter · #7 ·
Thanks again for the tips......

After talking to a K & N specialist the other day he advised against using a universal cone filter for the classic 900 Turbo because all it will do is draw warm air into the engine from under the bonnet, creating running problems..... A few other specialist outfits also advised against this option, whats eveyones view?

I'll get some photos sorted soon, the exhaust system is pictured in the 1986 accessories cataloge....
 

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warm air intake

It's not a problem. I've been running like that for years! the only problem is that you're not really increasing your horsepower becasue you're sucking warm air. Cold air is more dense than warm air ie there's more oxygen in it. I am working on a design to dam off the air after I install a FMIC

I also would advise against castrating your APC via a ball bearing. Cheap performance not propper performance.
 

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I have got the Speedparts open air kit installed.


It is a bit of a tight fit, but it sucks in cold air.
 

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Do NOT use thatball bearing tip please... it makes no sense and could/most likely will cause great harm to your Saab's motor. If you really wanna go for it, fine - but we at TSL do not reccomend it by far. It is NOT a good MOD. :cry:
 

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As far as air filters go K&N or ITG are commonly used by people with tweaked C900's. You won't notice much, if any, gain in performance, but it will help the engine to handle higher power levels. To be honest, I have heard a lot of people disappointed with Abbott. They cost a lot, and don't give that much gain. Trent is probably a better bet if you really want to get someone else to do it. However, it is very easy and relatively cheap to increase the performance by playing around with the APC as suggested on www.900aero.com. If you've got an APC you may as well use it, but mine is an LPT (well, ex-LPT), so I'm using an MBC to give 1 bar boost. Raising the boost will stress the engine more, so make sure it is in good condition before you do anything. Also, if you don't already, start filling up with Shell Optimax - it is 98.5+ octane, and makes a huge difference to mine without costing much more. Let us know how you get on. And avoid that ball bearing thing :wink:
 

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I made my own cold air induction kit from some Saab bits, some sFs Silicon joints, a Race-X cone filter and tumble dryer vent hose.



BTW, also an '85 T16S B plate.
 
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