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Discussion Starter #1 (Edited)
I have recently added a Fast ethanol/alcohol air fuel meter on my Cole Tr 4, Blown 540.

I am running e85. The ideal number appears to be about A/F ratio of 7.5. Fast meters tell me the numbers between 6.0-9.0 is good.

The readings I got initially was A/F ratio 8.5 to 8.6 during run. That probably isn't far from where it should be, but I wanted to bring the number down (richer) slightly. I changed from 101 jet to 103 jets (QF).

That run gave me a reading of about A/F ratio of 8.3. It did make more power.

I have had limited testing time, but my questions are, would a jet change of 2 sizes or about 9% create a variation of almost a 2 and 1/2 point change in the A/F ratio and would the ideal A/F ratio of 7.5 be the same for naturally aspirated and for a roots blower set up?

(Originally posted as 6.3 and not 8.3 in error.)
 

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Highaboosta
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Here's the chart to go by,


Don't go any richer than the rich best torque number.

I run 7.2:1 A/F with up to 30# boost and that has worked fine.

Do you have an intercooler ?

Where do you have your O2 sensor installed ?
I assume you plugged all the water drip holes in the primary tubes and it's sealed good at the flange gasket.
 

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Discussion Starter #3 (Edited)
I have the sensors located where the collector becomes round (after primaries and the collector where it is formed to accept them). They are sealed well, water and weep holes have been plugged.
They were placed a few inches in front of the pan-vac and 90 degrees.

There is no intercooler, but I am running the Indy blower manifod which has air running under the runners.

I have a hard time getting a steady number reading at idle or cruise. That could be because the collector is of the short style (bassett) and outside air is getting sucked back in. At wide open throttle, the number becomes very solid or stable.

I know you are running a turbo set-up, but do you know how sensitive these meters are in regards to a 2 jet size change?
 

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Highaboosta
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Plug the hole to the pan-vac while your tuning.

The numbers may jump around a little but not large swings.

While it's idleing cover 3/4 of the end of the header and see if that stabilizes the readings.
Is there any vaccuum line from the base of the carb to the valve cover ? plug that temporarity.
My O2 is about 8" from the end of a 5" pipe and the readings are steady.

Was there any calibration procedure for the new unit ?

Two jet sizes should not have made that large of an A/F change.
Maybe around .5
Is low idle vaccuum causing the PV to open ?
What is the idle vaccuum as compared to the # on the PV ?
 

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Discussion Starter #5
There is a calibration as to whether it is ethanol e98 or e85 or methanol and individual header sensor readings or combined ( I set mine for combined).

I am running two 9375-1's (1050) with Quick fuel metering blocks and boosters. There are no power valves.

Covering part of the header may resolve the idle reading fluctuations and I wouldn't think the pan-vac would be causing a problem with its location, but that is a good idea to try.
 

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Discussion Starter #6
OK, more information.

With the 103 jets, The A/F reading was closer to being correct, I think. The 2 jet size change from 101 to 103 dropped my number about .1 or .2 to 8.4-8.6.

Should a 2 jet sizes be showing more than a .1 or .2 difference? I would like to be closer to the 6.5 A/F ratio during a run. With the numbers I am getting, I need to richen it up 5 jet sizes at least. It seems like a lot, but who knows.

Opinions or experience welcome? I am running out of boating season quickly.
 

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Highaboosta
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OK, more information.

I would like to be closer to the 6.5 A/F ratio during a run. With the numbers I am getting, I need to richen it up 5 jet sizes at least. It seems like a lot, but who knows.
Opinions or experience welcome? I am running out of boating season quickly.
Why would you want to be richer than the rich best torque number on the chart ?
Any richer than 6.9 A/F will decrease power.

How much boost are you running ?
 

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Why would you want to be richer than the rich best torque number on the chart ?
Any richer than 6.9 A/F will decrease power.

How much boost are you running ?
Lets not forget that this stuff is 85% ethanol. If you run it richer than you need to, all your doing is washing down the cylinder walls with one one the best solvents on earth. The mis belief that rich is good, richer is better, falls down with alcohol. With alky, rich is good, richer is death. Bad enough that this thought is rampant in the gas ranks, alky guys know better. You can kill a motor with fuel just as easy as you can by taking it away. And when its blown, even quicker.



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Discussion Starter #9
Perhaps I am missing something. If I am running an A/F mixture of 8.5 and I want to get to an A/F mixture of 7.5, and if a 2 jet size changes the A/F mixture of an A/F reading by .2, then wouldn't it actually require a 10 jet size change to get to 7.5 from a 8.5 reading.

That sounds like a lot, even to me.

Isn't the A/F reading of 7.5 pretty close to what I would want as a reading on a run? (which is richer than I am now with 8.5.)

The boat actually seems to be running pretty well like it is.
 

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OK, more information.

With the 103 jets, The A/F reading was closer to being correct, I think. The 2 jet size change from 101 to 103 dropped my number about .1 or .2 to 8.4-8.6.

Should a 2 jet sizes be showing more than a .1 or .2 difference? I would like to be closer to the 6.5 A/F ratio during a run.
Your post said 6.5. I think thats what threw Unchained and myself. You could try putting in another 2 jet sizes and see if the change is roughly the same. But to answer your question, 2 jets sizes is considered the minimum to see a change.
I know this sounds crazy, but it is possible to make a 2 jet change and change very little. Because Holley jets are rated at 2% per change with a possible 2% varience +/-. It is possible to have zero change with 1 jet size.
Your next 2 size jet change could make twice the difference and it wouldn't surprise me. Going 10 jet sizes to get where your going wouldn't surprise me either. But I wouldn't go more than 4 with the next change.

I don't consider anyhting less than 6 sizes a big swing. remember, a power valve can equal 8 easy. And thats with gas!



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Highaboosta
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Lets not forget that this stuff is 85% ethanol. If you run it richer than you need to, all your doing is washing down the cylinder walls with one one the best solvents on earth. The mis belief that rich is good, richer is better, falls down with alcohol. With alky, rich is good, richer is death. Bad enough that this thought is rampant in the gas ranks, alky guys know better. You can kill a motor with fuel just as easy as you can by taking it away. And when its blown, even quicker.
SOME alky guys know better. Some have no clue.

I was at a local lake a couple times this summer where they have drags on late friday night afternoon.
There was a Stealth jet with a 14-71 blown alky motor that looked to have all the right stuff to take the show on about any day. All the right stuff except for the proper tune. It was so rich it was just blubbering. He couldn't run with the other lake boats there.
I questioned one of the locals about it and he said it has run like that for the last 5 yrs. That's some of what I see on the water with guys who run methanol.
Sure had an impressive blower surge though.
The zoomie headers made 1500 hp worth of noise too. :rolleyes:

Some don't seem to realise that you get too rich with any fuel and you REDUCE HP. That point is 12.5:1 with gas and 6.9:1 with E85.

There's only a handful of us on this site that use a wide band O2 sensor and know exactly what the A/F ratio is. The rest ................?
 

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That right there is why guys refrain from going to alky. They see the same things you do. And so it becomes "too complicated."
 

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The other variable here, is sometimes e85 isn't e85.:)bulb It could be e80 or e75. Production vehicles can run on any concentration of ethanol, so there is no requirement to supply e85. As the weather changes, so will the concentration of ethanol.
 

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Discussion Starter #14
I did put 6.5 didn't I. I did mean 7.5. It is hard to help a person when being given the wrong information.

There aren't many people who really have that much experience with E85. I am trying to learn what I can and be able to understand what happens in the real world, as opposed to what is advertised or someone thinks.

I have had a little more experience with the the Fast Ethanol meter now. What I am seeing is numbers fluctuating at lower speeds, but when the water is smooth and the boat is run up to 40mph or so the numbers stabilize a lot better. On a run the numbers will give me readings very stable with a variation of + or - .1 of the A/F reading.

I will like the meter much better after I get their module kit connected so it will show the rpm along with the A/F reading and it can be downloaded to a computer for comparisons.

My problem right now is that it is PC based and I use a Mac. My previous computer was a Mac powerbook with virtual p.c. installed, I don't know if I can get it to be compatible or not. I may have to resurrect an older PC my wife use to use that needs some work.

Thanks for the help and insight.
 

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Discussion Starter #15
On the Variations with E85, I do have the Quick Fuel tester and test each batch purchased. Since I have only purchased it three times, my experience is still pretty limited.

What I have seen has been virtually identical each time, with readings of 85 or 86. I know there are winter, summer blends, but the summer time is the only time I will be buying it.

I talked to one distributor locally and was told there is a federal law as to when the time for the different blends were to be made. That was last year. This year the person I talked with, was unaware of there being any change here. (Texas)
 

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Depending on where you are and where you buy it, it will take a pretty big swing summer to winter. With the summer having the highest ethonal content. In Montana or Denver in winter, the lowest. trying to start a 85% mix in sub freezing weather could proven to be a bitch. This why the extreme % variance is why they had to make the fuel system in the vehicles so flexable. You need to test every load of fuel.



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That right there is why guys refrain from going to alky. They see the same things you do. And so it becomes "too complicated."
Although I agree with you completely, its ignorance. Now one says that when they see a gas motor huffing black smoke and running like crap. They just figure the guys doesn't know how to tune. But if its on alky deal, its because he doesn't know the magical mystery tune that very few know.:)sphss Your right though. People are scared of something they have never tried.



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Is anybody running E-85 with stack injection on bbc, if so what compression, how bad is fuel consumption, a little on your setup ,etc
 
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