[ricot83]

i found this link tonight... this is even more proof that we have same power potential as viggens, it just seems crazy

he dynoed 224whp stock

then witha jt exhaust and dp put down 7hp more but with taller rims though
http://www.saabnet.com/tsn/bb/performance/index.html?bID=80534

so i guess the autos not only have less torque, but also less hp to the wheels as shown by my dyno, once steve dynos his car in jan we can compare even further

 

[SaabTuner]

he dynoed 224whp stockr

:lol:

 

[ricot83]

y funny?

 

[stevehayes01]

I keep seeing more and more data that would support that the T7 can learn and adapt to producing more HP within its range than everyone has said. This is quite interesting that all of these 9-3 SE HOT's are putting down wa more power than what they should put down with the T7 system. It has been made out that the T7 is very rigid and leaves only a few percent +/- of adjustment but all of these cars keep popping up that disprove that!!!! That is a great thing to hear and thaks for the info Ricot!!! Keep it coming!!!!

 

[CO-Saab]

Based on that graph those numbers are corrected. Top right corner reads:
CF: STD (Correction Factor: Standard) Still loads of power, but not 200+WHP.

 

[stevehayes01]

Even with Standard correction factors applied it is still producing more than what has always been said a T7 would produce with bolt ons. This gives me hope that the T7 is way smarter than everyone gives it credit for and can handle more power based on modifications prior to ECU remapping. WE will see when I get my 2000 9-3 SE HOT Auto dynoed what it pulls in stock form and hopefully it will give the same results we are seeing on other 9-3 HOT's and it will be higher than expected. Fingers Crossed!!! :shock:

 

[SaabTuner]

:lol: I apologize in advance for this, but I can't help it. Just laugh with me, ok? Cuz there's no way you're going to be able to prove that it was the exhaust which gave it that 7 hp; not when the car has more than 7 hp variance in airflow completely stock.

I had 7 hp between runs on the SAME car on the SAME day, within 10 minutes of eachother completely stock. And I have datalogs showing more than 11% variation in airflow completely stock and both on race fuel (no knock) The variance is even greater without race fuel, obviously.

See, look ... first I made a run to redline in 3rd gear (22.5 lbs/min, not even my lowest stock run):

Then I poured liquid schwartz into my gas tank and got 20 more hp worth of airflow!!!(24.45 lbs/min three times):::

:shock:

Let's all go down and buy more liquid shwartz for our T7 engines!!!! 20 hp difference on the SAME day! 7 hp even on the dyno! (206-213)

Seriously guys. It's probably not the exhaust. I'm not telling you not to get exhausts, cuz there's nothing wrong with a good exhaust system. But you need to realize that it's just not going to make that much of a difference.

Moreover, as the air-mass/combustion goes up, the ignition timing goes down. So even if you force more air in by magic, you don't gain any significant more power. My dyno runs may have had huge differences in airflow, but because the timing got pulled during high airflow it only made 7 hp difference, not 20. The same thing would happen with exhausts which only pull more air out of the engine.

And even if, as in this case, you get more hp on the dyno with your exhaust, you have no way of knowing if it would have done that anyway because of how much it varies stock.

[ do reccomend an exhaust and possibly an 06cm^2 housing for guys on 91 octane because, even if you don't get any more air into the cyllinder you WILL get more heat out of it. Good for "mechanical octane". 8)

Starting to see the light?

Adrian~

 

[SaabTuner]

Sorry about the double-posts ... but I would highly reccomend a larger exhaust housing if you're going to do an exhaust for your car. On the 05cm^2 housing a couple quick calculations (did them just now) will show that gas speed is well over the local speed of sound at 5,000 RPM. Once the gas reaches the sound barrier it is governed by normal and oblique shock relationships and is now a compressible fluid.

Once the gas through the turbine reaches the local speed of sound the only way to increase the mass-flow through the orifice is to increase the absolute pressure or the size of the orifice and pressure-ratio no longer has any significant effect. This means the backpressure from your post-turbo exhaust system will have neglidgable effect beyond 5,000 RPM because pressure ratio no longer dictates flow, only absolute pressure.

Mean Piston Velocity @ 5,000 RPM: 2.0L 13 m/s ----- 2.3L 15 m/s

Exhaust gas temperature: ~1073*K

Local Speed of Sound: 656 m/s (1,466 mph)

Gas Speed Assuming No Speed of Sound in the 05 cm housing @ 5K RPM: 2.0L 662 m/s ---- 2.3L 765 m/s

If you look at the turbine maps at ATP Turbo you can see the choke flow; it's when the corrected exhaust gas flow no longer increases with pressure. (The mass-flow still goes up, but not the velocity.)

The same calculations for an 06 cm housing, the exhaust temperature, and thus speed of sound, are assumed to stay the same:

Gas Speed Assuming No Speed of Sound in 06 cm housing @ 5K RPM: 2.0L 551 m/s --- 2.3L 636 m/s

You can see that with the larger 06 cm housing neither the 2.0 nor 2.3L reach choke flow before 5K rpm. After getting the larger housing, a better flowing POST-TURBO exhaust will make a significant difference in top-end flow ... and power too if you get a good tune.



Adrian~

 

[stevehayes01]

Ok Adrian I think you missed my point here. I am not saying that the Exhaust gaveit any great increase here or that the bolt on Mods are superfantastic and wonderful and great.

What I am saying is that a factory certified Master SAAB tech showed me in Black and White the WHP numbers for the 9-3 SE HOT and it is not 200+HP the autobox was listed at 178WHP and the 5sp. was listed at 185WHP. I was remarking that every T7 SE HOT car that dynoes seems to be well over the "Rated, LIsted, Published" WHP numbers. What that tells me is that either the T7 has more room in its sliding performance scale then everyone wants to believe (which gets my vote) or that SAAB grossly underrated the cars output to fool the EPA when the got the car certified for sale in the US.

I do appreciate you posting all the mathmatical calculations for everything you have been figuring out but from my experience in the past a bench work dyno and the real thing rarely ever meet up and match each other. There are just too many factors that you cannot account for on paper that come into play on a real car.

Not that I think that you don't know what your doing in an engineering capacity because I am quite impressed by your display of numbers and computations. It seems to me that there are more and more people springing up out of the wood work to substantiate what I have thought all along and that is that SAAB underrated the car's HP and gave the T7 (atleast in the HOT models) the ability to adapt up to near viggen specs based on boltons.

You and I live in the same area and therefore have the same temps and conditions to contend with on a dyno so theoretically our results should coincide. I will be getting my car on the Dyno the first week of January and if my car comes in with more WHP than 185 then that will be 3 of 3 SE's that are running more HP that what SAAB claims they do and I will be convinced further that the T7 is more adaptable and capable than people give it credit for.

These are just my thoughts and opinions and nothing more so please dont take offense I just go by the hard facts that get presented to me.

 

[SaabTuner]

The HOT's are underrated. They have more than 205 bhp.

The previously quoted 230 crank, corrected horsepower sounds about right from what I've seen. Of course then many Viggens run crank hp in the 250+ region, along with 280+ lb-ft of torque, so it's not quite the same. But it's close.

When Saab rated the engine 205 hp was probably the minimum the car would produce without knock. There's a lot of run-to-run variation. I don't think it's the bolt-ons that are increasing the power.

And what do you mean "bench dyno"? I posted real-world dyno-runs and datalogs showing real-world airflow. There's nothing bench-dyno about that.

The stuff on the turbine housing was just to give direction. It also gives a good solid explanation of what ERP has shown with data-logs. I hope that doesn't constitute a bench dyno. Just kidding.

And thanks for the respect about about the numbers. I spend a fair amount of time collecting them and posting them to get people talking. You don't have to agree with me. But some people don't seem to even care that I put effort into posting it. *sniffle*

Anyhoo ... if you want to prove an exhaust made more power, the only way to do so is to make numerous runs before and after and compare the averages. That'd convince nearly anyone!

Also, if you have a data-logger, see how much airflow you can coax out of it. The theoretical limit for B235R is about 25 lbs/min, and I have yet to reach it. Maybe an exhaust will help? Worth a shot. (The value for the 2.0 is lower. I don't know how much though.)

Adrian~

 

[stevehayes01]

And what do you mean "bench dyno"? I posted real-world dyno-runs and datalogs showing real-world airflow. There's nothing bench-dyno about that.

Adrian~

What I meant by that was not directed to you but rather directed at trying to calculate the flow and performance of a vehicle on a virtual platform. I realize that you posted dyno's so don't take offense to that statement as it was not directed to you.

I still do believe that the SAAB T7 is capable of more than what everyone says or expects without throwing a CEL or reducing power output based on mods.

 

[SaabTuner]

I don't think it would throw a CEL with a few mods. If it was on low octane, like here in Cali, an exhaust and an intercooler would probably do T7 a world of good on our hot summer days! It'd be like having higher octane.

If you put an exhaust on T7 you have to wonder why the ECU would allow more air. T5 doesn't "see" the air, which is why you get more power. A Subaru's boost control system doesn't "see" the extra air either. (It's fuel mapping does, but not boost control.) But the T7 boost, fuel, and ignition computers all "see" the extra airflow. If they are designed to allow more airflow, what stops it from just running more boost while completely stock?

More importantly: The throttle is the mechanism that stops the engine from running too much boost (mg/c) when stock. How does that change with an exhaust mod? Why wouldn't the ECU close the throttle just like before when it reaches that same value? :?:

See what I mean? With any other turbo car you get horsepower because the part of the ECU that controls the air going into the engine doesn't "see" extra airflow. Trionic 7 does see it. :? If Trionic 5 could "see" the extra air, it would stop it also!

Anyway. Someone with some mods needs to get a data-logger to see how much airflow is getting into their engine! That'd be a lot more putatively accurate than a dyno-run since all our MAF sensors are calibrated more or less the same, whereas dynos are not! :shock:

Adrian~

 

[ricot83]

ok the point of this post has nothing to do with the 7hp gain, but more so with the stock numbers , also i am happy to hear that with a 6cm2 housing i can flow better cuz thats what i have.

 

[stevehayes01]

Ok point taken Ricot! It is killing me having to wait until January to get the Dyno done on my car!! I want to know what it is putting down so I know where I stand. Sorry for high jacking your post man! :shock: :shock:

One more question Adrian....

If you run 110 Octane Race Fuel the T7 will produce more power because it see's less knock or chance of knock right?

Simply stated that is the whole basis of the T7 is to keep in the "Safe" zone of operation and run right on the edge of that boundary right?

So the higher the octane the less chance of knock the higher the T7 should allow the HP output?

This is derived from the theory that the T7 will only let the car run until there is a chance of Knock so it would make sense that the higher the octane the less knock potential there is so the more HP that would be derived.

 

[ricot83]

which brings another question steve.... u guys dont have 93 octane in ca right? because i believe thats what i was using on the dyno

 

[stevehayes01]

Nope we dont! :evil: We have 91 but I will add in a gallon or 2 of 104 Race gas when I go so that should give a little bit more balance to it. We do have more consistent weather than most places with less adverse conditions and such. I usually run octane boosters in my car so I can atleast get to that awe inspiring 92Octane. I ran 104 Race on my C900 and I was able to pull 19PSI on a modded APC unit so I have faith that race gas will do a little for the T7 to equalize it a bit.

 

[SaabTuner]

T7 has an "optimum map". I actually have seen the "optimum" knock-retard map, though I have been asked not to share it. (And I will honor that request.) I do not want to lose the trust of the person who shared it with me. I do not want to make a big deal about that either.

I cannot be specific, but I think I can safely share some very basic non-numerical information. I cannot tell you the actual values, but this is useful even without the actual values ...

I use 91 octane and in cool weather I usually have the "optimal" spark map with only a cooler thermostat an watter-wetter as "mods". Cali 91 octane, according to all the Subaru tuners, acts like 89 octane everywhere else. I think it is safe to assume that 93 octane will produce an "optimal" map 99% of the time except perhaps in 95F+ weather.

The engine will run the "optimal map" as long as there is no knock, and no heat-soak. Even on 100 octane race fuel the engine will lower boost after a couple hard runs. I believe this is to prevent long-term damage from a high EGT. An exhaust won't change this since the ECU cannot directly measure the drop in EGT from the exhaust.

Because the engine does not usually have any trouble with knock, especially not on 93 octane, I don't believe the mods will allow any more power. T7 will not run unlimited boost until it knocks. Having run 100 octane fuel several times I can tell you that T7 generally runs as much boost on 91 octane (read: more like 89) as it does on 100 octane. Mods won't change that.

Does that make sense?

Adrian~

p.s. Rico, definitely right about T7 cars being underrated for the most part. Was that really the point of this thread though? You said in the beginning about T7 being more responsive to mods. Most of the comments I made were to try and show that those increases were probably just random. My car increased several horsepower each time I ran it.

 

[ricot83]

it really was the point... i am not sorry that this thread took the turn that it did though because i have learned a bit more.... and that is the best part of forums... is what u leanr.. :lol: :wink: :wink: :roll: see i spell new things everyday....

leanr

 

[ERP]

Adrian, I agree with your theory about exhaust gas flow through the turbine housing. But I want to throw in another variable. The pressure difference across the wastegate flap. As the exhaust gas flow velocity increases so does the pressure. At some point the pressure difference between the exhaust housing and downpipe will be large enough to force open the wategate and divert part of the exhaust gas flow.

The wastegate flap area is ~0.80 in^2 and the wastegate I tested took about 15 lbs to open the flap. This means it would only take a pressure difference of 18.75 psi to force the wastegate open. Seems really low. But even if this value is off by several factors it is still likely that the wastegate being forced open would be enough to limit the exhaust gas flow to subsonic speeds. Of course the flowrate through the wastegate is extremely important in this assumption so it should be calculated.

Once the wastegate is open it creates lots of turbulence. Which is where a larger diameter downpipe would become beneficial and an external wastegate becomes ideal.

Eric

 

[SaabTuner]

I respect your oppinion, ERP, but I'm not completely convinced that's a problem.

The ventury effect should lower the pressure against the wastegate because it is normal to the flow direction. Via the Bernoulli equation, high velocity gas has a low static pressure in the direction normal to the flow. However the Bernoulli equation only works for incompressable gasses, which means gasses well under the local speed of sound. The speed of the gasses near the wastegate is borderline ... though at the end of the nozzle it's reached mach 1.

On an exhaust with the stock manifold, the "bends" in the manifold will convert a lot of that velocity pressure into static pressure, which can "make it" out the wastegate.

On an exhaust with tubular headers, Dr. Boost (from the Saab factory) has noted that there are sometimes "problems" with the wastegate. Sometimes he says it cannot dump enough pressure! Quite the opposite from dumping too much. This is because the velocity pressure is maintained, and very little static pressure exists to "turn" at a right angle out the wastegate.

Do I make any sense?

Here's a page from the Glenn Research Center at the NASA website on static and dynamic (velocity) pressure: http://www.grc.nasa.gov/WWW/K-12/airplane/dynpress.html

Only static pressure can make it out the wastegate.

Adrian~