When it was 90 degrees here i had my alky set on 6. Now that it is about 45-50 degrees at night should i be running my alky a little lower? Around 4 or so? I say this because the other night my car was running sluggish top end, cutting out and someone said it could be because my Alky. Thanks to everyone in advance for the help!:smile:
Alky Control Setting...
- Thread starter GNAT87
- Start date
Blown&Injected
Active Member
- Joined
- May 31, 2001
I am new to alky but I would say keep turning it down while watching KR and see what happens
BlackMetal
Active Member
- Joined
- Sep 29, 2005
Good question. One one hand you have colder air this time of year and may need less alky in terms of intake air temperature. On the other hand, cooler air is more dense with actual useable oxygen, so maybe you would need to turn the alky up?
I had my GN out the other day when it was about 40 degrees and got 2 degrees of knock on my Scanmaster after not seeing any detonation all summer long, made me think I needed to turn the alky up... (doesn't matter though because I'm not driving it again til spring).
Interested to see what the real alky experts would say. Less alky because of already cooler ambient air temps, or more alky because of a denser air charge...
But this is all just theoretical discussion. As B&I suggested above, you can just gradually turn the alky down as long as you aren't getting any knock.
I had my GN out the other day when it was about 40 degrees and got 2 degrees of knock on my Scanmaster after not seeing any detonation all summer long, made me think I needed to turn the alky up... (doesn't matter though because I'm not driving it again til spring).
Interested to see what the real alky experts would say. Less alky because of already cooler ambient air temps, or more alky because of a denser air charge...
But this is all just theoretical discussion. As B&I suggested above, you can just gradually turn the alky down as long as you aren't getting any knock.
Bingo.
"Tuning by ear" is a waste of time. If you want to know how much alky you need to run then you need to understand that there are several factors at work.
The first and most important is air fuel ratio. Alcohol is a fuel. The more of it you dial in on your alky kit the more air you displace in the chamber. Too much fuel costs power.
Knock suppression; we run alcohol to suppress knock. In a perfect world for boost we would run our engines on strictly alcohol to achieve the most knock suppression.
Since we don't live in a perfect world we squirt some alcohol into the mix to up the octane of the fuel and remove heat from our intake charge through the process of vaporisation.
The more alcohol you dial in without adjusting the gasoline side the richer your air fuel ratio is going to be. You must first have a good power producing air fuel ratio and then maintain that. Your goal should be to maximize the amount of alcohol your kit flows while maintaining the correct air fuel ratio.
There is no way to tell what air fuel ratio your car is running at WOT unless you have a wide band oxygen sensor. It is wisest to back up these readings with an EGT because if your timing is way off it can skew wideband o2 readings.
Some people feel that once you've added enough alcohol to prevent knock that you have reached the point where you have enough. This is true to the extent that you are at a point where your engine will be safe.
It won't however be as safe as it could be with more alcohol, and it wont produce as much power as it would with more alcohol.
It all comes down to the level you want to take this to.
But above all, it is a balancing act. Get the air fuel ratio right regardless of the amount of alcohol you run. My personal philosophy is to max out the alcohol and take out the gasoline to compensate. That way you wont wonder if you are adding enough alky to be safe.
Problem is making tuning decisions on "feel". You dont pull alky.. you reduce fuel.. now there comes a time you can overwhelm the motor with alky, but typically it lays down..
I would change plugs first, look at your air fuel, and make adjustments as the motor tells you to.
HTH
Julio
PS.. I have repaired way too many tuning problems with a new set of plugs
I would change plugs first, look at your air fuel, and make adjustments as the motor tells you to.
HTH
Julio
PS.. I have repaired way too many tuning problems with a new set of plugs
What do you mean by this? Overwhelm meaning you excessively richen the AFR? Or overwhelm that too much of your fuel is alcohol despite having a good afr?
So if you turn up your fuel pressure, do you think that your 60 pound injectors are going to flow more than 60lbs of fuel?
Most people think that they turn their alky pump speed up and they're going to get more alky spraying in the motor.
Not.
Volume decreases with pressure. No exception to the rule. So you turn it up, and line pressure has gone up, but your mass volume of alky is reduced.
The only way to pump a greater volume of alky is to increase nozzle size. Then when you do that, line pressure drops, atomization gets worse, and the only fix is to increase line pressure....turn the pump speed up.
Below a certain set point, on many systems, there really isnt enough line pressure for the systems to work properly. Like below 4 or 5 its pretty useless. I think the razor systems are so massive, that they can operate well at "low" pressures but my old SMC kit doesnt even hit 60psi of line pressure until I have it set to around 8-9. I always have my alky set to 10. This actually is spraying LESS alky into the system, but the atomization is far superior, the more line pressure you have. The more atomization=the more surface area the alky droplets have, which draws heat out of the intake charge much better. Plus this reduced volume is going to wreak less havoc on the tune.
My advice is to turn the pump up to 10, year round, and tune the engine around that setting. And I noticed by the way, that my turbo spools twice as fast with the alky set to turn on at around 7-8psi, instead of the 14psi I used to set it at.
Most people think that they turn their alky pump speed up and they're going to get more alky spraying in the motor.
Not.
Volume decreases with pressure. No exception to the rule. So you turn it up, and line pressure has gone up, but your mass volume of alky is reduced.
The only way to pump a greater volume of alky is to increase nozzle size. Then when you do that, line pressure drops, atomization gets worse, and the only fix is to increase line pressure....turn the pump speed up.
Below a certain set point, on many systems, there really isnt enough line pressure for the systems to work properly. Like below 4 or 5 its pretty useless. I think the razor systems are so massive, that they can operate well at "low" pressures but my old SMC kit doesnt even hit 60psi of line pressure until I have it set to around 8-9. I always have my alky set to 10. This actually is spraying LESS alky into the system, but the atomization is far superior, the more line pressure you have. The more atomization=the more surface area the alky droplets have, which draws heat out of the intake charge much better. Plus this reduced volume is going to wreak less havoc on the tune.
My advice is to turn the pump up to 10, year round, and tune the engine around that setting. And I noticed by the way, that my turbo spools twice as fast with the alky set to turn on at around 7-8psi, instead of the 14psi I used to set it at.
say what?
Ummm....Vader, the Volume (space it occupies) of a Gas decreases with pressure but it's density will go up. Not that that matters here, we're dealing with Alky as a non compressable Liquid. With any plumbing system your flow (or volume or GPM) will be effected by the nozzle restriction (size ) and Nozzle Pressure (Psi). If you have two of the exact same size nozzles one pmped at 50 psi and the other at 75 psi. The 75 psi system WILL flow more. This holde true up to the point where the friction losses in the rest of the plumbing begin to restrict flow. Not an issue with us.
Ummm....Vader, the Volume (space it occupies) of a Gas decreases with pressure but it's density will go up. Not that that matters here, we're dealing with Alky as a non compressable Liquid. With any plumbing system your flow (or volume or GPM) will be effected by the nozzle restriction (size ) and Nozzle Pressure (Psi). If you have two of the exact same size nozzles one pmped at 50 psi and the other at 75 psi. The 75 psi system WILL flow more. This holde true up to the point where the friction losses in the rest of the plumbing begin to restrict flow. Not an issue with us.
Lee Thompson
New Member
- Joined
- May 24, 2001
I can see it coming
Another pi**ing match. I'm not an engineer, just a dumb hillhilly, but why would the fpr have a boost signal to it if it didn't add MORE fuel (with pressure) as boost climbs? Why do we crank the fuel pressure up as we add boost if it don't put more fuel in the eng.?
Another pi**ing match. I'm not an engineer, just a dumb hillhilly, but why would the fpr have a boost signal to it if it didn't add MORE fuel (with pressure) as boost climbs? Why do we crank the fuel pressure up as we add boost if it don't put more fuel in the eng.?
Scott Atk
Senior Member
- Joined
- May 25, 2001
Vader is correct in general terms, but it doesn't really apply. Even the example of upping the fuel pressure on a set of 60 pph injectors is incorrect. The reason is because the regulator on the fuel system is after the injectors. You would be correct if you referenced a carbureted fuel system, where you raise fuel pressure by restricting the inlet to the carburetor.
On a RAZOR kit you up the pressure by increasing pump speed, the restriction (nozzle) stays the same therefore flow through the nozzle is increased.
On a RAZOR kit you up the pressure by increasing pump speed, the restriction (nozzle) stays the same therefore flow through the nozzle is increased.
Sorry there guys I botched that all up. What I meant to say was that the flow rate increase decreases with a pressure increase. Say the nozzle flows 1.00 GPH at 20psi. Double pressure to 40psi. Does the flow rate double? Nope. Its more like 1.5 GPH. This flow rate/pressure ratio is a curve that drops with pressure like a rock.
Saying that the amount of alky decreases with pressure was a goof. :redface:
Saying that the amount of alky decreases with pressure was a goof. :redface:
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