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Discussion Starter #1 (Edited)
Did some dyno runs today....new supersprint headers are on the way and I wanted to get some stock readings before going ahead with the install and tune. I'm pretty happy with the results. The three best runs are below, two in 4th gear and the best in 5th producing 339.85...but we can call it 340 since my math teachers always told me to round up. :grinyes: Stock engine w/ timmay signature muffler delete.

I wanted to get some opinions on my A/F ratio from those of you that have dyno'd their cars before and/or know what's normal. John at Carburetor Connection ( High Performance Auto Services | Hemi - BMW - Corvette/Camaro - Car/Truck - Carburetor/Smog Repair ),very friendly and quite knowledgeable with BMW's, thinks it might be running a bit lean and suggested I look into swapping the fuel filter and doing another dyno run before the headers go on. We decided the best thing to do would be to post the results here and get some feedback from the board in order to decide if it's normal or not. What do you guys think?? She has 47,157 miles with original fuel filter.

Graphs/photos/videos below. *edit - added a better A/F graph on at the end so you can see the #'s better*

Thanks,
JC

Run 3 - 4th Gear

Run 4- 4th Gear

Run 5- 5th Gear
 

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Nice numbers!
 
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Looks great for a stock car... I think you need some headers. :grinyes:
 
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Thanks for sharing the dyno vid's and stats. Nice numbers as many already mentioned. You should probably change the fuel filter anyway. They are cheap and it's easy to do.

Cheers,

Scott
 

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Discussion Starter #8
Why not just change the filter,...

Um just because...
Thanks for sharing the dyno vid's and stats. Nice numbers as many already mentioned. You should probably change the fuel filter anyway. They are cheap and it's easy to do.

Cheers,

Scott

Thanks guys. Most likely what I will do. Not too difficult and no better time than now.
 

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Very good numbers to start with for a baseline!
 

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Great numbers, J!

It gets a little bit choppy in the top end of the power graphs, which could mean nothing, but could also be an indicator that something is dirty in the intakes. I'd recommend replacing your stock air filters with OEM ones if you haven't done so since the last oil change, and perhaps clean the MAFs also if you haven't done so yet (I'm assuming you're still running your original MAFs with your low mileage). Lastly, fuel filter is a straight forward DIY to ensure proper AFR.

Torque and HP graphs look great. Very good upward pull on the HP and good looking linear torque graph. Wait till you compare your after-header and after-software graphs to these baselines you did today. I hope you're ready :hihi:
 

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Discussion Starter #14
Great numbers, J!

It gets a little bit choppy in the top end of the power graphs, which could mean nothing, but could also be an indicator that something is dirty in the intakes. I'd recommend replacing your stock air filters with OEM ones if you haven't done so since the last oil change, and perhaps clean the MAFs also if you haven't done so yet (I'm assuming you're still running your original MAFs with your low mileage). Lastly, fuel filter is a straight forward DIY to ensure proper AFR.

Torque and HP graphs look great. Very good upward pull on the HP and good looking linear torque graph. Wait till you compare your after-header and after-software graphs to these baselines you did today. I hope you're ready :hihi:

Yes, original MAFS.

I'll change out intake filters when I swap the fuel filter. I know there's a few threads on how to clean MAFS so I'll try to tackle that one on my own without making her explode.

Really can't wait for headers and powerchip...very anxious!
 

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wow that is very lean, how were the afr's monitor? with a sniffer type probe?
for a n/a car 13-13.5 would be optimal
HP/TQ numbers are stellar, but those AFR's are crazy lean. Tailpipe sniffers are not known for being all that accurate and the sensor might not be up to snuff. Hopefully those are not your actually readings. Car sounds good, though! :M5thumbs:

I'm also liking that RS up on the other lift!
 
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Discussion Starter #17
What sort of symptoms would my car exude during daily driving to suggest the A/F is that high?
 

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Nice natural shaped graphs but incredibly lean.
May well be a problem with the probe itself but you must investigate this further before doing anything else.
You cannot risk having the engine running that lean and he top end uneven power may be a result of this.
 

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Discussion Starter #19
Nice natural shaped graphs but incredibly lean.
May well be a problem with the probe itself but you must investigate this further before doing anything else.
You cannot risk having the engine running that lean and he top end uneven power may be a result of this.

Thanks. Going to swap a new fuel filter in and get back on the dyno before headers.

Anything else that could contribute to it being so lean?
 
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