help me with aerodynamics in my Chevrolet Blazer truck

[aerohead]

Originally Posted by guillermoariast

Hello, i have a Chevrolet Blazer which is not aerodynamic at all. Hence i need to modify several things.
I would like you to help me with ideas.

regards,
Guillermo Arias
Lima, Peru

Guillermo,I've located some figures for your truck,but need to dig a little longer.I think I can pull them together by this coming Saturday.
*You might tell us about your driving conditions there in Lima.If you do a significant portion of steady high-speed highway driving the aero mods should really help you.
*Also,it would be good to know about the Blazers gearing,and the kind of engine RPMs she turns at highway speed.
*I presume you have a thermo-clutch on the engines cooling fan?
*Is the original fan shroud still in place?
*How often do you use the 4-wheel-drive?
*Could you do with narrower tires?
*Could you get by with less ground clearance?

[guillermoariast]

Thanks for your post.

Originally Posted by aerohead

Guillermo,I've located some figures for your truck,but need to dig a little longer.I think I can pull them together by this coming Saturday.

Originally Posted by aerohead

*You might tell us about your driving conditions there in Lima.If you do a significant portion of steady high-speed highway driving the aero mods should really help you.

I drive the truck only on highway and off road ways because i have a car for the city. I use the truck only for travels.

Originally Posted by aerohead

*Also,it would be good to know about the Blazers gearing,and the kind of engine RPMs she turns at highway speed.

I do not know how are the gearings set.
The average RPM on highway is 3000

Originally Posted by aerohead

*I presume you have a thermo-clutch on the engines cooling fan?

Yes i have one

Originally Posted by aerohead

*Is the original fan shroud still in place?

I have not the original, but i ordered making a new one.

Originally Posted by aerohead

*How often do you use the 4-wheel-drive?

Not very often.

Originally Posted by aerohead

*Could you do with narrower tires?

I think it was not necesary buy the 31" tires. But I did. I could put some narrowers on.

Originally Posted by aerohead

*Could you get by with less ground clearance?

Maybe 1 or 2 inches less

[Debonair]

ah i love the K5 blazers, i was highly considering one.

Perhaps you can remove the cap and either make or buy an aerocap

[botsapper]

Many years back, sport truck customizers lowered, shaved & cleaned up a few Blazers & CK's. A new aero shell would be good.

[aerohead]

Here are some data on the Blazer:
* The Cd for the pickup on which the K5 is based is 0.535.The K5 will be higher due to exposed underbelly,wider tires,etc..
* The frontal area is 34.3-square feet
* CdA will be above 18.35-square feet
* Road Load 'dynamometer' @ 50 mph = 19.9 horsepower ( front axle not measured)
* Actual road load @ 50 mph approx. 24.142-horsepower
* Engine load @ 50 mph approx. 26.824 brake horsepower
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* 1974 C10 pickup @ 55-mph steady,with 250 cu in 6-cyl,4-speed manual,and 3:07 rear axle = 17.7 mpg.
* same truck,with softened hood leading edge,front airdam,and tonneau cover = 18.6 mpg.
* 1982 C10 w/ 6.2-liter Diesel 2WD = 31 mpg EPA HWY
* 1982 C10 w/ 6.2-liter Diesel 4WD = 29 mpg EPA HWY
* 1982 C10 --------------------- = 19 mpg EPA HWY
* 1986 C10,350 cu in V-8,Turbo-hydramatic w/ lockup,mild cam,performance intakemanifold,275X 60R-15 tires = 20 mpg @ 65 mph
* 1987 C1500, Cd 0.45,31.899-square feet Af (est), VORTEC V-6,M-5,@ 65 mph,with air conditioning and 1/2-tonneau cover = 23 mpg
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If you are very attached to the Blazer,anything you do to mimic the form of contemporary pickups and SUVs will pay you savings at the pump.
* JEEP has gone to air suspension on the new Grand Cherokee to lower it on the HWY.
* You see how all the 'noses' of current vehicles have been rounded.
* Drip edges have been eliminated
* Windshields and glass is more flush to the body
* The sides of the body are flush with the wheels,or vice versa
* Wheels are more 'enclosed' either as a wheel or with wheelcover
* Fenders and hoods slope downward
* Bellys are smoothed
*Airdams scoot the air over and around the vehicle
*Electric fans replace engine-driven units
*Grilles are blocked to restrict the amount of airflow through the cooling system
*Vehicles are 'longer' in relation to their height
*Rooflines are now mimicking the early Hungarian and German low drag forms of the 1920s-30s.
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The Blazer should respond very well to streamlining,however,since it is a carb'd engine,it's fuel metering system and BSFC will be more affected than fuel-injected vehicles.