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Discussion Starter #86
Well, my curiosity got the better of me and I decided to take the car back to the dyno for a few runs after putting in the Walbro pump.

Long story on the experience but the car did very well and I am now finally satisfied with the results.

I have included three graphs:

- Last run with OE Fuel Pump and lean AFR plus two runs with new Walbro
(For reference, run number 08 is the last run from my previous trip to the dyno.)

- Two runs from today

- AFR Graph from today zoomed in so it can be easily read.

We played with a few different AFR settings but running low 13s made the best power.

The average for the two runs today:

340.68whp / 359.45wtq

The car made 320whp+ from around 4.6K all the way to around 6K. Pretty decent curve for the HW IMHO.

Obviously the additional fuel cleaned up the plots quite a bit. ;ol;

D-
 

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Nice to see you got it sorted out D.
 

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I found a link to this thread from the Hybrid T28/T25 thread and I would be curious to see what your car made on 93 octane.

I can not believe you are running a FI motor as lean as you are but, I guess leaner, is meener. I'm sorry but 5 HP is not worth blowing a motor. You would be better off running 12.2 - 12.5 A/F to be safe. Otherwise, you have a ticking time bomb waiting to explode.
 

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Discussion Starter #90
I found a link to this thread from the Hybrid T28/T25 thread and I would be curious to see what your car made on 93 octane.

I can not believe you are running a FI motor as lean as you are but, I guess leaner, is meener. I'm sorry but 5 HP is not worth blowing a motor. You would be better off running 12.2 - 12.5 A/F to be safe. Otherwise, you have a ticking time bomb waiting to explode.
The car has been pounded this way for four years now and it's doing just fine. If it's a time bomb, it must have a hell of a long timer.

It's funny, on one hand you are implying that my target AFR of 13.2:1 at peak power is a large advantage over what could be done on pump gas, then in the next breath you are saying the difference in AFR is only worth about 5HP. Which is it?

Actually, I'll help you with the answer. The truth is that my leaner AFR is probably worth a little more than 5HP. However, to be truthful on the octane, a really sharp tune for my HW on 93 octane would probably make pretty dang close to the same numbers.


D-
 

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Discussion Starter #92
I would never run any of my cars that lean.
Well, I appreciate your concern but this ain't my first rodeo. I am an old codger (41) who has been racing for 25+ years. It's all good!

Just so you know, low 13s on AFR happen all the time with cars tuned for E85 or other high octane fuels. As a matter of fact, there are several other very fast SAABs on the SAAB boards whose tune has them in that range as well. You aren't comfortable with it, I understand. However, it's not really that abnormal.

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Well, I appreciate your concern but this ain't my first rodeo. I am an old codger (41) who has been racing for 25+ years. It's all good!

Just so you know, low 13s on AFR happen all the time with cars tuned for E85 or other high octane fuels. As a matter of fact, there are several other very fast SAABs on the SAAB boards whose tune has them in that range as well. You aren't comfortable with it, I understand. However, it's not really that abnormal.

D-
I'm not gonna beat the dead horse but...

You should find a way to get some egt numbers
 

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Well, I appreciate your concern but this ain't my first rodeo. I am an old codger (41) who has been racing for 25+ years. It's all good!

Just so you know, low 13s on AFR happen all the time with cars tuned for E85 or other high octane fuels. As a matter of fact, there are several other very fast SAABs on the SAAB boards whose tune has them in that range as well. You aren't comfortable with it, I understand. However, it's not really that abnormal.

D-

David, I don't want you to think I'm trying to take anything away from you by any means. The point I'm trying to make is 13.2 A/F at WOT on a forced induction motor is LEAN and unsafe.

It doens't matter if the motor has lasted for years running those A/F it's still lean.
 

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David, I don't want you to think I'm trying to take anything away from you by any means. The point I'm trying to make is 13.2 A/F at WOT on a forced induction motor is LEAN and unsafe.

It doens't matter if the motor has lasted for years running those A/F it's still lean.
Can't be that unsafe if it has lasted for years.
 

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Not trying to be argumentative but no "reputable" tuner has ever gotten 340+whp out of a similiar HW combination-AFAIK.

Just sayin'

D-
David, like I said I'm not trying to take anything away from you and it's great the your car makes the power it does and has lasted this long. But that doesn't change the fact that your car is lean.

I'm not just talking about Saab tuners, I'm talking about tuners across the board. It's one thing to risk a $2000 car it's another to risk a $10k motor. 13.0 A/F on a Naturally Aspirated motor is safe but not on a Forced Induction motor. I also have been doing this for years and of hundres of high HP cars (600+whp) I've been around not one, FI car was ever tune to run as lean as you are running your car.

Of coarse you will make more power when the motor is on the lean side but that doesn't make it safe.
 
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