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drmatera's Avatar
 
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New Dyno numbers...!

Well i made it back on the dyno this evening. I switched to running E85 last week and decided to put the car on the dynojet. I'll post up the dyno sheet tomorrow but here are the highlights.

the megasquirt boost controller worked great. I started the runs at just under 1 bar and the last pull was 1.2bar

final numbers were 370rwhp and 390rwtq at 10.7 a/f and 19-20* total timing. needles to say i'm very happy and i think the little k27 is out of breath. I did try a bit more boost but saw no increase in power, my inlet temps started at 88* and ended at 115* running from 3000rpm up to 5600rpm
Old 03-17-2010, 07:49 PM
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Nice. You should now switch to lambda units when showing AFR. It would be easier to compare different fuels that way, IMO.

Did you swap all new fuel lines and pumps when you moved to EFI? Do you know where you injector duty cycle is now with E85? I have a E85 pump close to my home but I don't think I can even experiment with it with CIS and without any digital WUR bits.

Was the 19-20* total timing the most you tried?
Old 03-17-2010, 08:08 PM
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Not sure why switching to lambda would help? I keep it on gasoline as they are familiar numbers I can easily recognize.

The lines and pump are all factory stock. We removed the fuel dampener but I retained the stock fuel filter. We used AN fittings to go from the filter to the rails, then another AN fitting adapts back to the stock return hose. Not sure how long the pumps will hold up to E85 but we'll see.

I found that adding timing from 2500 - 4500 helped power in the midrange (+10rwtq) but saw no real effect on peak power so i left it at 20*. Next time we'll revisit timing as last night was more about making sure everything was safe. I kept a/f in the high 10's as I was told that was best for running over 1 bar of boost.
Old 03-18-2010, 07:07 AM
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If you are at 13.6 A/F on gasoline you are 8.5% rich. On E85 you are around 38% lean (depending on the actual alcohol content).
If you use lambda a number of 0.8 means 20% rich regardless of the fuel.
Old 03-18-2010, 08:06 AM
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i'm only 38% lean if I have the a/f gauge reading for alcohol. If I leave it on gasoline the numbers mean the same (14.7 stoich) regardless of what fuel i run. Or am i missing something?
Old 03-18-2010, 08:10 AM
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Exactly the opposite. E85 has a different stoich value so you can't use a AF gauge for normal gas if you don't brainthrust the numbers for E85 first. Using lambda is a good way of thinking AFR as the values mean the same for every fuel type. I bet you are already searching for good read about this so you will definately get it figured out.

Wiki for the rescue for stoich numbers
http://en.wikipedia.org/wiki/E85_in_standard_engines

stoichiometric AFR:
GAS 14.7
E85 9.765

stoichiometric Lambda
GAS 1
E85 1

Last edited by smurfbus; 03-18-2010 at 08:58 AM..
Old 03-18-2010, 08:50 AM
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ok, lambda is 1.0
calibrating the meter for gasoline reads 14.7 at lambda
calibrating it for e85 reads 9.85 at lambda

my a/f meter is calibrated to display a gasoline reading. I understand when it shows 14.7 it really means 9.85 but the gas numbers are more familiar to me. I know how to calculate the conversion but prefer to see it in the gas format
Old 03-18-2010, 09:17 AM
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you can run leaner on e85 due to its cooler combustion temps. same way CART ran 20lbs of boost without an intercooler. only possible b/c of the cool combustion temps provided by methanol. or run richer and turn the boost up. Darin, get a turbo from Bello or Juan and turn up the boost.
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Old 03-18-2010, 09:29 AM
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in my water cooled engine i ran 12.0 a/f as most guys said they made peak power there, but after a nice long chat with Eddie i'm keeping her in the 10's. mostly due to running over 1 bar on an air cooled motor. I made a dozen back to back pulls and never encountered heat soak or any drop in power so the e85 must be doing something
Old 03-18-2010, 09:40 AM
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whats the most power you guys have seen out of a K27? I feel this thing is done as the last pull only made 17.5psi at peak then dropped as the rpm climbed.
Old 03-18-2010, 09:53 AM
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I haven't run E85 with AF meters that are calibrated for gas but for me it sounds you are running way too lean. On my audi I added 40% fuel when I tried E85 and that amount was good for similar AF as with gas. I used lambda with my LM-1 to check my AF as I don't have E85 calibrated AF gauge
Old 03-18-2010, 10:25 AM
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well, I added 25% of fuel across the board when i switched to e85. Keep in mind my gasoline a/f ratio was low 10's at the time so it is most likely about 35% richer overall than what a gasoline target would be
Old 03-18-2010, 11:35 AM
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From what I have seen the K27-7200 shows diminishing returns upwards of 350WHP. By 400WHP it is likely out of breath.
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Old 03-18-2010, 11:37 AM
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25% on top of 10AF on pump gas sounds reasonable. How is your start up now. I could not get enough start up fueling so it was a bit slow to fire up.
Old 03-18-2010, 12:18 PM
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It does take slightly more time to cold fire the engine, but once warmed up it's no different.
Old 03-18-2010, 12:37 PM
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I'm still puzzled about your AFR gauge readings. If it's showing 10.7 AFR with E85 and the gauge is calibrated for normal pump GAS then when using E85 it should actually be leaner than stoich. That is clearly not the case as you have added 25% fuel over the previous really rich gas tune.

Your gas AFR gauge should read around 8 AFR now! What kind of gauge is it? If it's innovate you can calibrate for E85 with your PC (maybe you did this?) or maybe the AFR you gave was from the dyno and the dyno operator already made the conversions?

Following numbers are from wiki and those max power values are too lean for aircooled engines but there is a guideline for therelationship between gas and E85 and AFR and Lambda.

Fuel AFRst Lambda
Gasoline stoichiometric 14.7 1
Gasoline max power rich 12.5 0.8503
Gasoline max power lean 13.23 0.900

E85 stoichiometric 9.765 1
E85 max power rich 6.975 0.7143
E85 max power lean 8.4687 0.8673

Its cool that you are experimenting with E85 and that would be one reason for me to go EFI if it works out good in the long term. Cooler is better and it's environment safe also.

Last edited by smurfbus; 03-18-2010 at 10:34 PM..
Old 03-18-2010, 09:26 PM
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Smurfbus,

I imagine the gauge measures lambda, and then displays the resulting AFR assuming you're running gasoline. So if you're running E85 at stoich, the gauge would show 14.7 even though the engine is actually at 9.76.
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Old 03-19-2010, 06:27 AM
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That is what I assume also. I think that is ok near lambda 1, but the further you go away from that the more inaccurate it is. The curves for E85 and gas are not just offset, they also have a different shape. It is not too innacurate, until you are more than 15% rich or lean.

What makes you think you are getting the "25% accross the board"? Maybe the injectors are saturated somewhere below that?
Old 03-19-2010, 07:26 AM
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Quote:
Originally Posted by Mr Beau View Post
Smurfbus,

I imagine the gauge measures lambda, and then displays the resulting AFR assuming you're running gasoline. So if you're running E85 at stoich, the gauge would show 14.7 even though the engine is actually at 9.76.
thank you
Old 03-19-2010, 07:27 AM
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Ok, I got it. The gauges really read Lambda and usually show the AFR for GAS so using E85 you just keep thinking GAS AFRs. It should be close enough to keep safe.

Last edited by smurfbus; 03-22-2010 at 11:08 PM.. Reason: got it.
Old 03-19-2010, 07:36 AM
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