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Discussion Starter · #1 ·
First, as a disclaimer, this is just an idea. It's not been tested, and it will probably worsen emmissions and fuel economy slightly.

So you thought your Viggen intercooler was restrictive?

This is right after your throttle body in your intake manifold on every 2001-2002 Viggen:



Looks a bit restrictive if you ask me. What do you think?

Since it is NOT fitted to all T7 cars, I'm led to believe it has no effect on power. It's purpose is to distribute the air evenly between the cyllinders when there is very little air-velocity after the throttle at lower power. But it may also help keep some cyllinders from running leaner than others. However, because it was not used in the 1999 Viggens, or ANY of the T5 cars with essentially the same intake manifold design, I think it's a matter of emmissions.

The WIS lists this as a piece which was fitted to LEV cars. Again, I think it's an emmissions thing. ;)

Now on cars with sufficient octane it shouldn't harm power. Remember, T7 will over-come restrictions like that by running more boost, but more boost = more knock, so if you don't have enough octane (like me) this will reduce how hard your turbo and engine have to work, and should increase power.

Now here's part two ...

The Viggens in 1999 and 2000 got a special intake manifold:



Because of the second gasket, the intake air isn't as easily heated by the contact surface with the head.

Unfortunately, 2001-2002 (2003 conv) all got the same manifold the B205 had getten in 2000 (and similar to the NG900 turbo manifold, but slightly different, and ALL of them have the strainer:



Because it's one piece, it will heat up the air slightly more. Good perhaps for fuel mileage, and cheaper to produce, but poor-er for knock sensitivity.

The cost for "upgrading" to the two piece manifold is high ($310 USD), but it's useful information for anyone doing any serious tuning. It would also allow custom manifolds to be made more easily because the flange which mounts to the cyllinder head with the injectors is $91 US, and is pre-fabricated and easily ported. Thus a custom intake could be mated with that flange fairly easily.

Just thought this would interest some of you T7 owners out there.

Here are the cars which the EPC says have the strainer:

1999: None
2000: B205L, B205R
2001-2002: All


Adrian~
 

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cool info adrian....

so whos going to be the first guinnie pig???

i would really like to know how well this will work!!!
 

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Car's not on the road yet, but I took mine out last month when I switched throttle bodies from T7 to T5....The "spaghetti strainer" diffuses the air but there's bound to be a flow penalty.

Only reason I can think of it being there is to prevent an unequal air distribution between the middle cylinders and the lonely ones on the end...
 

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Discussion Starter · #4 ·
Got an e-mail back about it from Nick T saying it usually caused more problems when removed. Viggen's didn't get it until 2001, and most of the Viggens with cracked pistons are 1999-2000 ... unhappy trend forming.

Then again, only 2001+ cars have it, and others run fine. (IE NG900's and such.)

Hmmm ...
 

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I took my spagetti strainer out last night. It took about 15 min.
I took her out for a hard test drive, and I didn't notice a power difference.
If there is an increase it's very slight, but hey these little mods add up.
Throttle response did seem slightly better though.
Of coarse only real way to see it's effects are on a dyno.

As far as one cylinder running lean it makes very little sense to me and I find it very doubtful that removing this will make your pistons crack.

Anyone else give this a shot?
 

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something tells me when you guys reach full boost on your cars...some very interesting results will happen.

Be careful when jumping on the band-wagon without a full appreciation for the reason why it was placed on to begin with.

regards
 

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I think you might wanna leave that part in there. This is just a "theory"!!! :roll: :roll: :roll:

notice how Adrian did not do this to his own car? :!:

If Nick T says it is not a good idea, he actually mods his car and dynos it to prove whether or not parts work and how safe they are, so if he says it is not wise, it is probably not wise.
 

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Discussion Starter · #10 ·
I don't think removing it will be "harmful". As has been pointed out, all NG900's have a similar manifold without it, and all the 1999 and 2000 Saabs did not have it.

The WIS also explicitly states that it is for Low Emmissions Vehicles. I'm leaving it in so I don't fail a smog check.

Or I may redesign the intake manifold. So that there isn't such a sharp angle between the entry of the throttle air and intake runners.

Adrian~
 

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I'm definetly NOT an engineer, and I respect everone's opinion/input on this.

It is pretty obvious to me that removing this piece will increase air flow through the manifold, and decrease pumping loss. I guess it could create a lean condition unless the T7 compensates for the better/more airflow. But why would it cause one cylinder to run leaner than another?

Can you imagine how crapily designed an intake manifold would have to be in order to actually warrant something like this?

The fact that there are like a million NG's out there that do not have these installed with 200,000+ miles makes me a little more comfortable.

Could someone explain to mean why they think that this will cause cracked pistons? I realize that the 1999 Viggens had alot of piston failure, and that they didn't have one of these, but they also had newly redesigned (lightened) pistons in 1999.

If you're going to prove me wrong could you please do so before I crack my pistons? :D
 

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All I am saying is that Adrian has not tested this out. He does not do any mods himself, just theorize about them. in most experiments, it is rarely or never that results are EXACTLY like theory. otherwise you could skip the experiement/testing stage, right? :wink:

I would think that it is there for a good reason, why would saab spend extra money for producing and installing this part for nothing. the part would not be in older models because as the model gets older, they make more and more IMPROVMENTS as they see things not working right or breaking prematurely. So again, they must have ADDED it for a reason. and if this was a good idea, someone who does mods and tests the before and after results like Nick T or one of the tuners like Maptun or SQR would do this type of mod. I have never heard of this before, so until someone PROVES it is safe and increases performance, I , personally, am not wiling to risk it. Certainly give it a try if you would like, but I am skeptical.
 

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You do also have to consider that Saab have also used such items as turbo silencers in the old style intercoolers. The silencer had a purpose, to quiet down the turbo noise, but it hampered performance.

my guess is that the strainer has a purpose, but that they weren't thinking of performance when they designed/installed it.

Is there soemone at Saab that we can contact asking what this thing is supposed to do and why it's there?
 

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2k193turbo said:
You do also have to consider that Saab have also used such items as turbo silencers in the old style intercoolers. The silencer had a purpose, to quiet down the turbo noise, but it hampered performance.
yes, but they removed in in latre models, while this piece was added in later models.

2k193turbo said:
my guess is that the strainer has a purpose, but that they weren't thinking of performance when they designed/installed it.
maybe they were thinking of sacrificing a few ponies to get more life from those pistons? I do not know for sure, but it strikes me as probably not a useless update if they added it on the last years/cars of that model run, when usually all the kinks have been worked out and problems addressed.

2k193turbo said:
Is there soemone at Saab that we can contact asking what this thing is supposed to do and why it's there?
that is probably the best idea. the folks at Saab would have data from tests and experiements to backup their claims and theories and be able to best explain why that part is there. i hope you can find someone, i would like to know more about this mystery part myself.
 

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mind you that saab is still considered a luxury car with power....remember that we here are an elite few who are concerned with the power of the car over the comfortable nature of the car hence when designing the car saab probably made it with comfort in mind as well as the life of the motor thus....you lose a few extra ponies for a quieter ride and longer lasting stock car
 

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OK..here's something that's got me spooked. I was snooping around My IM, and noticed It is not a 2 peice design. It's the standard one peice from the b205. Problem here is my car is a 2000. Meaning either my IM was swapped, or my motor is from a 2001(IM didn't look like it was seperated from head). Another thing I noticed is that the oilpan has been off the car. There was a bead of gasket goop around it. The motor is strong , silent and pulls like a freight train, but it is cause for some concern. I think I should see if I can get the service history.
 

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I second that. When you start seeing things that may have been tampered with on a newer vehicle that you didn't know about, that definately is something to be concerned with.


Getting back to the topic however, if you consider the characteristics of this "strainer" if basically leads me to believe that its simply used to disperse the air that flows in. With this in mind, and concidering that it wasn't used previously on any other Saab model, that further leads me to assume that it wasn't impleted to "reduce noise" or for any other reason similar.

I personally believe that its a device similar to the "Tornado" that alters the airflow in this case possibly dispersing air evenly to every chamber, thus not necessarily showing a large gain in power, but to increase gas mileage and emissions as stated previously.

Although I of course don't have a T7, I would agree that since it doesn't seem to show gains by removing it, perhaps it should be left in because it was implement later on by Saab, who could've saved money and just left it out. Just a thought :roll:
 

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Blaque_Out said:
Although I of course don't have a T7, I would agree that since it doesn't seem to show gains by removing it, perhaps it should be left in because it was implement later on by Saab, who could've saved money and just left it out. Just a thought :roll:
That's a really good point. With car companies trying to trim costs wherever they can, engineers wouldn't add something just for shits and giggles.
 

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Discussion Starter · #19 ·
I think that, because T7 will still put the same amount of air into each cyllinder, regardless of relatively small intake restrictions, that it's not something worth removing when stock.

However, I found further justification for my idea that it's more a "part-throttle" issue from Philip H. Smith's book on Exhaust and Intake systems.



Notice that the intake shown is fairly similar to the T7 stock style unit (some differences being siamesed ports, but the principle is the same), and that during part throttle the flow is erratic and less-stable; the air-flow into each cyllinder varies more with each revolution, so fueling is uneven. That would mean the strainer probably makes each combustion more even during part throttle, which again is more of a fuel consumption and emmissions issue than outright power issue.

Then again, if it's not hurting anything on a stock car, why remove it? I just think that once you've upgraded intercoolers, turbo, ECU, exhaust, etc ... then you might want to think of removing it for some extra flow. The reduction in flow resistance will keep the turbo from working so hard.

Adrian~
 

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Where did you find the reference to the air distributor in WIS? I see it in EPC, but not in the WIS...I have WIS version 3.0.0.0.

In addtion, it is only the 1999 Viggens that have the two piece manifold. I checked my 2000 Viggen, sure enough a one piece. I then check EPC....2000 Viggen intake manifold model number is 91-92-592, which is the same manifold listed in the B20x section. Primary manifold in 1999 for the viggen was 91-86-107 (ie the primary of the 2 piece manifold). The '01-'02 Viggens use 93-99-528 which is essentially the same as the '00, except is drilled for the different pressure sensor used begining 2001.

With all this I got to thinking that maybe the reason the 1999 viggens have only 225 hp compare to the 230 hp on the '00 and up is due to the different intake manifold design....this wouldn't suprise me as I know mind flow improvements to intake manifold can yield 5hp easily. That two piece I bet disrupts the air flow due to the additional gasket...gaskets normally aren't a perfect cut.

Jason
 
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