Cam Valve events ?s.
12-04-2018 | 06:31 PM
#1
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Cam Valve events ?s. Ok, here is my question, what is this the big killer of fuelmilage for a cammed car, besides how you drive, it gears.
Is it the over slap, how much is to much?
And still have the cam to perform in the upper rpm, have a wide lsa?
Thats what lm thinking.
Stampede
Is it the over slap, how much is to much?
And still have the cam to perform in the upper rpm, have a wide lsa?
Thats what lm thinking.
Stampede
12-04-2018 | 07:03 PM
#2
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From: Ohio, Georgia, Nevada, Texas
[QUOTE=Stampede4ever;20011583]
Torque per cubic inch is an interesting thing. More heartily faught than horsepower per cubic inch.
Pumping losses are best described as what your feeling when you lift-throttle at 4000 rpm. Those forces feel like Immediate slowdown. Diesels don’t experience that. No throttle blade closing to impede as your engine making it act like an air compressor driven by the rear wheel.
With gas, its not as apparent because positive and negative port pressures work actively on each other for 720 degrees. Also acting upon whatever is left of the mixture at any given point.
Then how do we maximize? It’s gets even better because you can short shift. Imagine having enough torque per octane per rpm of highway speed to be wot at 2500 instead of 3000 rpm. Less intake revolutions at wot inhale less air/fuel.
With that non-answer; let us know your thoughts along with your engine, driveline, and what you are trying to achieve for horsepower/mileage balance.
Ok, here is my question, what is this the big killer of fuelmilage for a cammed car, besides how you drive, it gears.
Is it the over slap, how much is to much?
And still have the cam to perform in the upper rpm, have a wide lsa?
Thats what lm thinking.
Stampede
[/QUOTEIs it the over slap, how much is to much?
And still have the cam to perform in the upper rpm, have a wide lsa?
Thats what lm thinking.
Stampede
Torque per cubic inch is an interesting thing. More heartily faught than horsepower per cubic inch.
Pumping losses are best described as what your feeling when you lift-throttle at 4000 rpm. Those forces feel like Immediate slowdown. Diesels don’t experience that. No throttle blade closing to impede as your engine making it act like an air compressor driven by the rear wheel.
With gas, its not as apparent because positive and negative port pressures work actively on each other for 720 degrees. Also acting upon whatever is left of the mixture at any given point.
Then how do we maximize? It’s gets even better because you can short shift. Imagine having enough torque per octane per rpm of highway speed to be wot at 2500 instead of 3000 rpm. Less intake revolutions at wot inhale less air/fuel.
With that non-answer; let us know your thoughts along with your engine, driveline, and what you are trying to achieve for horsepower/mileage balance.
Last edited by Summitracing; 12-04-2018 at 07:25 PM.
12-04-2018 | 07:35 PM
#3
Overlap is the big killer because raw fuel can short circuit from intake valve to exhaust valve more easily with more overlap. Low dynamic compression is another mileage killer
12-04-2018 | 07:40 PM
#4
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Darth sends it best. Sometimes an answer is better there than one that leads to another question.
Last edited by Summitracing; 12-04-2018 at 08:20 PM.
12-04-2018 | 08:33 PM
#5
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From: Ohio, Georgia, Nevada, Texas
Many people don’t and want to be told one thing more than another. And it’s only Tuesday. Some companies/persons will talk people into parts that don’t make them go faster. That’s not our way.
12-04-2018 | 08:56 PM
#6
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My current setup will be a LQ4, with 799 heads, LS1 intake, 220-224, 112+4, 0.575 lift, a TR-3650, 3300lb mustang, my next setup I'm thinking about will be rectangle port heads, ls3 intake, and the Stage 1 ghost summit cam, Specs are 222/233 .600 .575 115+3.
I'm hoping to be around 400 with first setup, around 450 with the rectangle port setup, and I would like to see 22-24mpg with either setup.
Stampede.
I'm hoping to be around 400 with first setup, around 450 with the rectangle port setup, and I would like to see 22-24mpg with either setup.
Stampede.
12-05-2018 | 12:24 AM
#7
I think the 220/224, 112 cammed set up will get pretty good mpg with -2 degrees overlap.
The 222/233 115 is about -2.5, would expect good mpg with it too.
The 229/229 114 in my 91 RS's 383 LS1 has 1 degree over lap. 24-25 mpg highway. Best of 25.5 mpg
The 222/233 115 is about -2.5, would expect good mpg with it too.
The 229/229 114 in my 91 RS's 383 LS1 has 1 degree over lap. 24-25 mpg highway. Best of 25.5 mpg
Last edited by 99 Black Bird T/A; 12-05-2018 at 12:32 AM.