i have a spreadsheet with 83 FD dyno plots. power at 6 rpm levels.

5000
5500
6000
6500
7000
7500

all adjusted to SAE correction, then summed and ordered low to high. highest number wins the race. this is "hp under the curve." of course i could have included higher RPMs but by doing that i would have lost quite a few entries. one of the reasons for my interest was to learn where the power occurs rpm-wise.

the 83 entries show:

5000 12.2%
5500 14.7
6000 16.8
6500 18.2
7000 19
7500 18.8

i am running a fairly large G40-1150 turbo and have been routinely making around 600 at 22 psi on E85. i was interested as to the lower rpm power so i entered the data from my last (May 23) run. i found it was pretty good around 5000 but something else jumped out at me that i thought might be worth sharing. i noticed a sag v the average power distribution V rpm around 6000/6500. then i noticed my AFRs. a perfect correlation.

i divided the average AFR (10.69) into the average power allocation (16.61) to find a multiplier so as to position AFRs on the chart.
the horizontal line is the average % power dispersion. the green line represents my AFRs.

my power dispersion is blue. the 83 others are red.

notice how i overperform the average early and underperform it later until the last data point.

now notice how perfectly being rich correlates w lower than average output.

10.8 on E85 is my "perfect" AFR. 'back to tuning.

how does your power allocation V rpm look?
. .

 

I'm not understanding this... Got a dummy's version?

 

the graph supports too trich you lose power. not a new concept but crystal clear once i add a few (missing) details.

X axis is rpm. 5000-7500.

Y axis is %. the % of the total power from each of the 6 data points.

the horizontal blue/green green line is the average of the % power 16.61%. used as a reference

the red line is the average of 83 dyno runs... % of total power at each rpm

the red line is my last run's dyno power points.

the green line represents my AFRs. when the data points are above the horizontal line i am lean, below rich. they correlate perfectly against the 83 dyno run averages... in the beginning i am relatively lean and the motor is generating more power than the population, then the motor goes rich and i fall behind. the last data point i am back to being towards lean and am above the population.

nothing new here but just a clear reminder the AFRs matter.

the tables on the left could use better titles... "average" refers to the average of the 83 dyno charts..

 

Howard, curious to see what kind of AFR targets you are running. And I assume these are all mostly pump and methanol? Or are some of the 83 also include e30-50/pump and methanol?

And are you tuned VE?

 

The real question is what is your target or limit EGT when choosing your lambda compromise.

 

currently on E85 w 775 100% meth. meth is for IAT reduction. 10.8 target. i will eventually get back to pump and meth after October. i may do some additional tuning as to timing.

 

Some more questions-

Are you changing your tune and timing with the fuel change?
Did you tune first, then add methanol for temps? Or did you tune while using methanol?

 

"Are you changing your tune and timing with the fuel change?"

yes. i ran 93 pump and varying amounts of 100% meth as AI from 2003 until 2013. around 500. Power FC days.

prepping for the Oct 2013 Texas Mile i switched to E85. along w GT4094r, ViPEC V88 and aT56.

after 2013 i ran mostly pump w meth AI and later mixed in 30/50% ethanol. i recently learned that it is the gas portion of such a mixture interacting w ethanol that forms the tar so i won't be doing the 30/50% mix w gas. it will be either Shell 93 and meth or E85 and meth. the meth is there to lower IATs. (as much as 60 F) i am going to evaluate injecting it into the compressor housing. i had 450 F coming out of the turbo in March and that wasn't at full throttle.

since ethanol has an approx 30% faster burn speed than gasoline i run less timing for ethanol. 9 w 14 split works well for me around 600 22 psi.

i consider the 775 cc of meth ( 8.5% of total BTUs) as part of the base tune.

 

Equal parts interesting and concerning. Could you point to some references, please.

 

"references, please."

i will dig around and can come up with the info.

 

"i recently learned that it is the gas portion of such a mixture interacting w ethanol that forms the tar so i won't be doing the 30/50% mix w gas. it will be either Shell 93 and meth or E85 and meth. the meth is there to lower IATs"

"references, please."

i am very happy that i ran into the YouTube video tonight. i hadn't bookmarked it and was only halfway through the 2 plus hours when i was interrupted. the interview is very interesting. i learned lots and still haven't reached the end. the guy is Sam Barros. he is Director of Research for Nostrum High Performance. they are a Mich based company that make cutting edge DIrect Injection systems. he also owns a company called Power Tuning Labs and, supposedly, is the ultimate GTR tuner. i can't, ATM, give you the exact time when he mentioned gum build from mixing gas and ethanol... it is in the first third of the interview. when i get time i am going to relisten to the whole video and will post it.

 

Thanks, Howard, looks like I've got some learning to watch this weekend. Cheers!

 

Watch the video using a browser on your laptop or desktop. Click the "more" link in the Description to expand that section. Scroll down until you see Transcript. From there you should be able to Ctrl F to find the text string you are looking for.

 

Good hack sir... obrigado.

The section discussing manually blended 30-50E gasoline-ethanol is ~16:45 - 21:00 . Coincidentally, my current ~E60-E70 is nicely compliant.... well along with street configured E09.