Performance Boats Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
436 Posts
Discussion Starter · #1 ·
Can someone please tell me what the perfect conditions would be for highest HP. How cold is too cold....how dry is too dry....and how does altitude play in all of this. FOR A N/A MOTOR. Thank you.
 

·
Registered
Joined
·
8,169 Posts
Sea level

Can someone please tell me what the perfect conditions would be for highest HP. How cold is too cold....how dry is too dry....and how does altitude play in all of this. FOR A N/A MOTOR. Thank you.
Kinsler's 100% air density calibration factors, 29.92 barometric pressure @ 59*. (I believe I remember water grains under 45 PPM as being acceptable but not part of a density gauge calibration). Contrary to popular belief, foggy nights do not create the best air for NA engines....Too much water in the air and water doesn't burn real well.........Ray
 

·
Registered
Joined
·
436 Posts
Discussion Starter · #4 ·
the calculator above indicates the colder the air the better....anyone know what conditions are best for HP....ideal conditions.
 

·
Resident Ford Nut
Joined
·
10,102 Posts
the calculator above indicates the colder the air the better....anyone know what conditions are best for HP....ideal conditions.
The first engine shop I used that had a dyno ran a few engines at night. I saw a few dyno sheets with air temps of 52-54* and a good barometer reading. The corrected numbers where under the observed numbers. The dyno program corrected down something like 8-12 hp.

Can't tell you if 45* would have made more power.

S CP
 

·
Registered
Joined
·
436 Posts
Discussion Starter · #6 ·
A car and a boat run stronger in the winter...correct? The air is colder and more dense so a NA motor is getting more oxygen that is matched with more fuel thus more power....correct? How cold is too cold....I would image there to be more experiences with a boat since a car would not be drag racing in 30* temps (icy roads). Is there too much of a good thing? Is there an ideal temp for max HP?
 

·
steelcomp was here
Joined
·
26,529 Posts
Kinsler's 100% air density calibration factors, 29.92 barometric pressure @ 59*. (I believe I remember water grains under 45 PPM as being acceptable but not part of a density gauge calibration). Contrary to popular belief, foggy nights do not create the best air for NA engines....Too much water in the air and water doesn't burn real well.........Ray
What about the cooling effect on combustion chamber temps and fighting detonation, or reducing chamber volume and raising compression a tad? It seems every car I've ever driven ran better on a foggy night.
 

·
steelcomp was here
Joined
·
26,529 Posts
A car and a boat run stronger in the winter...correct? The air is colder and more dense so a NA motor is getting more oxygen that is matched with more fuel thus more power....correct? How cold is too cold....I would image there to be more experiences with a boat since a car would not be drag racing in 30* temps (icy roads). Is there too much of a good thing? Is there an ideal temp for max HP?
You have to remember tht what you're trying to do is start a fire. While cooler air is more dense, and you can add more fuel, you're also making it harder to ignite.
I don't know what it is, but at some point there has to be diminishing returns.
I also don't believe in "cool cans" for fuel.
 

·
Resident Ford Nut
Joined
·
10,102 Posts
.
I also don't believe in "cool cans" for fuel.
I always wanted to hook one up on the dyno. I know two people who have used them, both swear by them. The turbo guy really loved his.

Years ago Honda found that their turbo engines liked the air temp around 104* for best vaporization of fuel and best power:
http://www.performanceboats.com//showthread.php?t=2357

But they weren't burning gasoline. ;)

S CP :D
 

·
steelcomp was here
Joined
·
26,529 Posts
Does cooling the fuel really make more power?
 

·
Registered
Joined
·
1,134 Posts
I've seen pictures of some of the big names in Pro Stock back in the day such as Dick Landy running cool cans under the hood. But that was 40 years ago.
 

·
Premium Member
Joined
·
25,975 Posts
Does cooling the fuel really make more power?
It can help a blower or turbo deal by absorbing more heat getting to the vaporization point. More power? It can help stave off detenation, and allow a little more timing. But all this kind of gets back to the original question of the thread. You can only have the intake so cold be fore the fuel won't vaporize quickly enough before ingition, and power falls off. But at the same time, I prefer not to have my fuel hot either. Like one year at Laughlin, 116 in the shade, and we after we filled the tanks, one hour later its perking out of the vents because it had expanded that much.



100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3
 

·
Bostick Racing Engines
Joined
·
1,063 Posts
Does cooling the fuel really make more power?
Nitro guys think so... cooling the fuel right before putting it in... in the staging lanes. NHRA must think so... they are no longer allowed to have a cooled fuel tank and from what I hear... chilling the fuel is now a no-no.

But then again... that's nitro... and I believe the purpose is more towards being able to have the fuel at a higher percentage nitro with the temp correction facor seeing as they are now strictly enforcing the percentage limit during fuel checks... after the run.
 

·
Registered
Joined
·
441 Posts
You have to remember tht what you're trying to do is start a fire. While cooler air is more dense, and you can add more fuel, you're also making it harder to ignite.
I don't know what it is, but at some point there has to be diminishing returns.
I also don't believe in "cool cans" for fuel.
Cold air and water make a difference,I know ya Know, But it is pretty noticeable and the Lakes up here create a heavy wet atmoshere. Back to back runs are not the same but most the time the power is there. I notice this with a carb blower motor.
 

·
Banned
Joined
·
1,263 Posts
I have tested (racing - not dyno) in conditions down to -27 F. Fact not rumour. 2cycle and 4 cycle sleds. I'm older now, so I made it a personal rule not to go out in anything colder than -15F or so. :)bulb

We also have local ice racing (cars/modifieds/sprints/etc) and have helped tune a few. The colder it is out, the faster they'll go - if tuned for it of course. Getting oil temps up is important and coolant temps really depend on the engine and engine build. Some can run 120F or so and others need to be as high as 180-200F. Compression and cyl head alloy seem to be the bigger influences.

BTW: ice slivers getting into air bleeds and even main metering circuits is a very real problem at these temps. Humid days have frozen water vapor in the air. Burndowns (holed pistons) are a very real issue because of the ice in the air(edit in: somtimes fuel) and more importantly being tuned for normal 50F+temps vs -F temps.
 

·
Banned
Joined
·
1,263 Posts
A few more things.

Intake manifold temp on wet flow intake manifolds (note: carbs !) can be crucial also. Fuel puddling wreaks havoc - especially at lower speeds. Add in bigger cams with their resultant lower intake vacuum and low speed driveability suffers badly. Top end hp not as bad. Even running an engine at say 50F that's tuned for 70+F, you'll see this. Now get down to freezing and below, and the Air gap style (dual and single planes) really start to suffer. If there is not enough warm up time, sometimes a heated intake (not saying hot) will ultimately work better.

Secondly, fuel itself. We have 'summer blends' and 'winter blends of fuel.' A big mistake can be gettingt fuel before the seasonal fuel changeover takes place (or the station used still has 'summer' gas) and using it in cold/very cold conditions. Driveability and power can go out the window. Starting even, can be a beatch. We ran into this , this past winter. Our 93 octane fuel from local place did not fill up with the 'winter' blend, since gas was so high $$$ no one was using that fuel for their cars or boats. So, we ran into older fuel that was still the 'summer' blend. out came the sleds and ice racers and real bad things happened. I can name about 8-10 local high strung sleds that went down for the count. I ended upo tracing it down to the same local station and same 93 octane fuel. Uuuurgh. Not a whole lot of gas stations to chose from around here.

Lastly - in this post - once in a while we'll have a big high pressure system over our heads and dip down into the 30's at our local drag track before the season ends (or just after it opens) and man do the cars fly. Yes, tuning has to be involved for most. This is when personal/professional records start to fly.

As a note: it was 26F coming into work this AM. So, yes, I deal with a lot of cold weather throughout the year.
 
1 - 17 of 17 Posts
Top