: Turbocharging an NA... again
16-07-02, 04:30 PM
I'm still wondering what needs to be done. I've talked to a specialist SAAB mechanic about it and he says the engine is built solid enough I just need to lower the compression ratio by putting a 2.3L header on. Is this true? Also are there any adverse effects to lowering the compression ratio when the car is not yet turbocharged? And are there any formulas for calculating how much the compression needs to drop before I can get about 25-30 PSI out of the engine?
low compression NA engine will be very slow and torqueless....
hard to drive until u get ur turbo.....
lack of piston oil squirters in engine could be a problem....
I thought Turbo and NA both had same compression from factory......
17-07-02, 01:49 AM
What are piston oil squirters and what do they look like?
they apparantly exist in the bottom end of the (turbo) motor and squirt oil at the bottom of the piston during running.
It serves as lubrication and cooling....
I have never pulled apart a saab turbo motor so i have no idea what they look like...
17-07-02, 06:03 PM
Sorry, guys I have to disappointed you, If one can find Piston squirters in the half bottom, it should have a gold medal.. Because those do not exists.. (only old B-block in 900 might have those)
Oil goes trough oil-lines in a block + (oil galleries) cranksaft squirts oil when it rotates.
cylinder block In N/A and turbo are same (ncludes H-engines 900 and 9000 till 1993?)
Compression ratio is in 9000
B202i N/A engine 10:1
And Turbo B202 9.0:1
But N/A B202S is 9.0:1
I believe that 16v 900 should have same numbers as well. (overall, compression ratio should be for that psi´s in turbo engine, between 8.5:1 - 9.0:1)
It is not worth of doing, from N/A engine, Buy a whole turbo engine and swap it, or swap the car.
17-07-02, 08:19 PM
Why is it not worth doing?
18-07-02, 12:28 AM
N/A 16V engine: For the block, you only need to get the Turbo pistons. If you intend to run high boost, you also might want to look at possible strenghtening mods, but that's only necessery when power reaches 300 hp levels. Also, with high boost like that, you might want to get 900 T8 APC pistons, which are just as strong, but give lower compression, making higher boost possible.
As for the head, I'm not completely sure, but 16V N/A and T16 heads should be alike. Please, someone correct me if I'm wrong...
Again, for high boost levels, the head will require some work to make the tuned engine breath more freely; it also helps reduce the increased head temperatures. No use really to get a 2.3 litre head, since with that kinf of boost levels, even that would require work. So just get a 2.0 T16 head and get that prepped by a reputable racing engine mechanic.
For anything above 14-16 psi of boost, you will also need a bigger turbocharger. The standard unit can produce more pressure than that, but will soon wear out due to the excessive heat being produced when forcing more boost than designed out of the stock turbo.
You will also need some serious injection upgrades: bigger injectors, a better suited fuel pressure regulator and also an extra injector.
And water injection is almost a must-have if you really want to get to 30 psi!
Plus, a 3-inch exhaust will be called for. And, preferrably an external wastegate, which, in return, will make it sensible to invest in tube header that will allow more efficient placing of the wastegate to get full use of the unit.
And you can also prepare to say goodbye to many gearboxes too, if you don't buy a strenghtened box...
Good luck! It'll be a fun car when you're finished, but it'll take a lot of work and patience!
18-07-02, 05:22 PM
I agree with Janne, 16 V N/A and Turbo heads are same, only the camsafts have different degrees and lifts.
Turbo Half bottom have forced lower pressure pistons, but con rods and cranksaft are identical with in N/A and Turbo.
Smackrazor, if you are handy and U can do all labour by yourself, go ahead, but still you might want choose an easier way..
18-07-02, 05:25 PM
Ok, what size turbocharger would you recommend for that and what is a tube header?
18-07-02, 07:18 PM
Also, should I bother wiring in an APC or should I get one of these other turbo management/knock sensor things? Would wiring effort still be about the same?
19-07-02, 04:57 AM
Smacrazor, turbocharger sizing comes down to what you want to accomplish in your project.
The stock Garrett TO3 will only be good for about 1.1 to 1.2 bar of boost. It will be capable of producing more boost, but at that level, it will produce much more heat than boost pressure. This will reduce the effect of compression as well as risk the turbocharger to be damaged.
Figure out what kind of power you are after and choose the turbocharger accordingly; if you only want, say, 250 hp, an ultra large turbo will only make it a pig to drive. With a large turbo, you get more boost capacity, and you will get more power with the same boost pressure, because a bigger turbo won't heat the air as much as the harder-working smaller unit would to produce similar boost levels.
I suggest you consult a local turbo specialist when you have a clear vision what kind of power/driveability combination you are trying to achieve - a good professional will know how to achieve it!
A tube header is an exhaust manifold that has a separate tube for each exhaust port - the gasses are extracted more efficiently when mixing pulses of the exhaust flow won't harm the flow of the separate ports. Then in turbo applications, there's a collector just before the turbocharger to get the gasses together before entering the turbine. In an optimal solution, the tubes for each port are made equal in lenght, and this will provide a steady, efficient flow for the turbocharger. Racing engines have such a setup. Tube headers, if custom made, will also give you a good opportunity to move the turbo unit to a more efficient location; i.e. so that the flow from turbo intake and to the exhaust, respectively, will be as efficient as possible. And this way you can get an external wastegate positioned optimally, which will be a great improvement if you are after high output.
Then, fitting an APC could be a good thing, but if you really are after lots of power, you will need to improve the ignition and injection systems as much as to make it worthwhile to invest in a completely new engine management system that has ignition and injection systems incorporated. A unit like that, Haltech F9a for example, can take care of boost control very efficiently as well. And it will enable fine tuning of all the engine's systems to exactly the spec you like. A system like that is going to cost money, about 2000 $ plus fitting, but it will really transform the car. And say goodbye to injection, ignition, turbo control and all other problems that you have to face with OE parts.
19-07-02, 03:47 PM
So the APC completely replaces the ECU so I don't need to get fuel stuff remapped, and it's a lot cheaper than a haltec. There aren't many turbocharger specialists in america, they all like the big blowers. I guess 250 hp will do for a daily driver. So anyway in order to do that I need the following:
+Turbonetics T3 w/Ceramic Ball Bearings
+2.0L Header Race Prepped
+2.0L T16 cams
+Blow off valve
+3" stainless steel exhaust
+30lb/hr Injectors (need more calculations based on air/fuel ratio)
+Rising Rate Fuel Pressure Regulator
+Magnecor R-100 spark plug leads
+GReddy Iridium SVS plugs made by NGK (NGK type BCP6ES)
+HKS Twinpower spark booster
+Square Fuel Rail
Or are there some mods in there which don't need doing and some which do need doing which I have missed out?
If power is your ultimate goal, a custom inlet manifold and plenum chamber might be nice...
The long inlet runners in the stock ones are good for torque but a slight hinderance with power production.
19-07-02, 10:28 PM
Actually I'd rather have monster torque than monster power. 300 ft lbs might be nice :grin:
20-07-02, 08:50 AM
Ignintion timing should also be focussed on; the stock vacuum/boost ignition advance controller isn't very effective, and is a drawback even in a standard c900T. I couple of friends of mine have used MSD boost timing master (MSD BTM) units to good effect. These things cost about 300$ and make it possible for you to set an accurate amount of ignition advance for each level of boost pressure - between every 0.1 bar. That's heaps better than the stock system that has a permanent timing change once boost comes into play.
But, as I see what kind of money you are going to invest in your car (all those special parts) a management system really would be a wise choice. There are alternatives to Haltech too: DTA,Electromotive, Hestec, SDS etc.
Those systems will improve your possibilities to set the engine up greatly. Different systems also mean different costs, and the Haltech system is by far the most expensive of the common-market management systems. For information about installing an SDS system in a c900 T16, go to http//saabnet.com and search the tuning forums for Vincent Tong's project - contact him for very good information and explanation just why it is worth the money and effort to get a full management system instead of OE components upgraged one by one.
Good luck for your project!!
20-07-02, 03:56 PM
Ok, I'll look into Haltech and SDS. Now where would I get my hands on a suitable wastegate, and are there any companies manufacturing tube headers or would I have to go down to my local speed shop and get something custom built.
most aftermarket turbo accessories manufacturers make an extermal wastgate. Probably doesn't matter what brand....
Once you have chosen/purchased a turbo and wastegate, your probably best getting an exhaust/speed shop to build an exhaust manifold for your specific application.
21-07-02, 03:26 AM
That's right... But there is a tube header for the T16 - Speedparts Sweden sell these.
It's a direct replacement for the OE manifold, but if you are getting a big turbo, and especially an external wastegate, you will be better off with a custom header instead - it will be easier to fit the wastegate to an efficient position. Plus you can relocate the turbo unit if you want to.
21-07-02, 05:22 PM
But then you said stock unit is good up to 1.2 bar which is still a lot of boost. Also it would be cheaper to get this unit from speedparts rather than have something custom built myself.
Also what is inefficient about the current wastegate location?
Your current wastegate is inefficient because it is internal. The fitment of an external gate will be far more efficient.
Anyway arn't you the one who listed external gate in your list of things to buy.
I personally doubt that the price difference will be that great between you sourcing and importing a swedish part and having a custom unit made locally.
I am not familiar with the Speedparts tube headers but i assume it places turbo in the stock position for simplicity of other plumbing. This is not the most efficient position as it is cramped and has extremely unequal exhaust collectors.
A better setup would be to mount the turbo beside the engine (or where the battery is) and use exhaust runners that are tuned length for better boost response. On a local lancer GSR i have read that 13kw (at same boost level) at the wheels (4wd) was gained from the switch from a stock manifold with adaptors made to a proper tuned length tube header setup.
An added advantage of the new position is the ability to position the compressor inlets and outlets for easier plumbing when running a front mount IC.
22-07-02, 02:31 PM
I'm doing exactly that in my project; there's the power gain, then there's the quicker response and there's more room in front of the engine to move the radiator back for a really large FMIC, for example.
If you get the header custom made, be sure that the people who do it know what they are doing - the wastegate especially, is crucial to fit in a right angle and position.
The inefficiency about the stock wastegate also includes it forcing the wasted exhaust gases to take a 180-degree turn before flowing out through the exhaust - and this isn't ideal.
22-07-02, 04:53 PM
Hmm... ok. Well I've never actually looked inside a c900 turbo engine bay so I can't visualize what you guys are talkign about too much. Next time I'm at the scrap yard I'll take a look.