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Here's my "dyno"
2 Attachment(s)
2003 5AT sedan
This is on a dynopack in Houston Texas - ambient air temp was 98deg. Engine was at operating temp. (mods in sig, except this was before the e-fan - yes DaveB, I intend to get another one :) uhhhh.....ok, so I was after a baseline, but I got this... Several things going on; 1. operator error 2. software (looping) issues 3. trying to dyno in 4th, resulted in kicking back to 3rd. hence the loops 4. headings are wrong -clearly this is not flywheel So clearly there were several issues - and I am getting a free session to get a cleaner run, but my main question is - can anyone knowledgable review the A/F ratio and comment on it. Also, where it says "Ratio", "TCF" and "Gain" - what does the "Ratio" mean? |
those are decent numbers, i guess thats what im looking at more or less when i do a dyno... btw check your pm's
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+1
Hope you get better numbers on your next run. Numbers look right though. |
...except this was before the e-fan - yes DaveB, I intend to get another one :) The numbers look good for a Dynapack. I've never seen that little loop on a dyno :p |
You a/f's look to be in good shape. You're right at 13:1 later on, and according to people more knowledgable than myself, these engines make most power at 12:8 to 1.
You seem to be lean at the bottom. It's not a big deal, that's common, and expected. Do you get any pinging on the road below 4k rpms under load? |
Originally Posted by trey.hutcheson
You seem to be lean at the bottom. It's not a big deal, that's common, and expected. Do you get any pinging on the road below 4k rpms under load?
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Originally Posted by trey.hutcheson
You a/f's look to be in good shape. You're right at 13:1 later on, and according to people more knowledgable than myself, these engines make most power at 12:8 to 1.
You seem to be lean at the bottom. It's not a big deal, that's common, and expected. Do you get any pinging on the road below 4k rpms under load? Nope, no pinging - I do use 93octane here in texas :D |
Wow that is one strange looking dyno.
Don't worry about the "flywheel" most dyno's say that for some reason... |
Originally Posted by DaveB
The high A/F below 4000rpms is pretty common for most cars. It's quite normal to 15:1 A/Fs under initial tip-in and sub 4000rpms.
My suspicion is that this is making a biiig difference to my bottom-end torque. I know when it is cold, it runs much stronger until the engine warms up. Is there a way to confirm the A/F is affecting my bottom-end (below 4,000)? And what are the ways to alter the A/F ratio? |
Originally Posted by andycon
'scuse my ignorance..but is that "high A/F" - as in running lean? (more air to fuel ratio)?
My suspicion is that this is making a biiig difference to my bottom-end torque. I know when it is cold, it runs much stronger until the engine warms up. Is there a way to confirm the A/F is affecting my bottom-end (below 4,000)? And what are the ways to alter the A/F ratio? |
Here is my dyno from dynojet.
And it is stock bone ( Blue line) mods' Vs ARK single 3" prototype exhaust system( Green Line). Before Dyno : 2003 G35 Sedan A/T - All stock 8/11/2006 / 3:26PM 98.48F Humility 17% After Dyno : 2003 G35 Sedan A/T - ARK DT-S Single 3" Pipe Exhaust System. 8/11/2006 / 4:39PM Temp 98.64F Humility 24% Was HOT day for Dyno test. And no time for ECU reset... But it is great results. Dyno result : 9.16rwhp / 10.25Tq Gain. http://www.arkperformanceusa.com/pho...um/dynog35.jpg Dyno Video Clip: http://www.arkperformanceusa.com/pho...to=830&cat=509 http://arkperformanceusa.com/photo/d...no_Custom_.jpg http://arkperformanceusa.com/photo/d...EM_Custom_.jpg http://arkperformanceusa.com/photo/d...no_Custom_.jpg http://arkperformanceusa.com/photo/d...07_Custom_.jpg http://arkperformanceusa.com/photo/d...1_Custom_3.jpg |
Originally Posted by godmans
higher A/F number means leaner (the ratio of Air to Fuel, i.e. 15 part of Air to 1 part of fuel). You can fine tune your A/F by using one of the piggy backs or reflash by TS.
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Originally Posted by trey.hutcheson
You a/f's look to be in good shape. You're right at 13:1 later on, and according to people more knowledgable than myself, these engines make most power at 12:8 to 1.
You seem to be lean at the bottom. It's not a big deal, that's common, and expected. Do you get any pinging on the road below 4k rpms under load? I agree it seems to be lean. My dilema is whether I would see any noticable improvements (reflash or piggyback) and would it be effective/beneficial? (in terms of getting the A/F more linear - around 13:1 and richer on the low-end)? |
Yes per that graph you were running way way too lean. But then again you also didn't have really any correct data at that part of the dyno test either so I would ignore those readings till you get a good run. Your after 4k looks normal with the rest of the dynos I have seen.
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IMO, his A/F is completely fine. It totally fine to have A/Fs in the 14:1-15:1 in the lower range (sub 4,000rpms) because cylinder pressure and heat isn't that high. As the rpms build, cylinder pressure and heat builds up in the combustion chamber hence the reason more fuel is added (ie to cool the combustion chamber) to reduce the chances of detontation.
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