Shadow Lou Racing, street,track,autocross Goblin

George

Goblin Guru
Test drove long way home with engine cover in place. Not satisfied with results. Back ground have front firewall and cut down windshield (ckeck earlier posts)
Hot air comes out the slot in picture. Will have to make a filler for gap.

Brad
 

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George

Goblin Guru
ZZP helped with the replacement of my worn camshaft, happy they were able to help off set the cost.

Brad
 

George

Goblin Guru
Auto crossed today, first time since modifing the frontend. The front worked great. But car is loose in rear on both accleration, decceleration and neutral power. Removed spring cushions did not do eonugh. Ordered a pair of 125# and a pair of 100#. Will try them and see what happens.

Brad
 

ctuinstra

Goblin Guru
Auto crossed today, first time since modifing the frontend. The front worked great. But car is loose in rear on both accleration, decceleration and neutral power. Removed spring cushions did not do eonugh. Ordered a pair of 125# and a pair of 100#. Will try them and see what happens.

Brad
What springs are you using currently. I couldn't find that info. Are you running an anti-sway bar? I assume not and it would probably only make it worse in the rear.
 

George

Goblin Guru
I have 400# front with 50# spring cushion with 175# tender springs. The rear are DF coilovers with 150# springs the spring cushions are 40#. I do have modifed rear steering knuckles that lower the ball joint 1.3" the rear of car sets a 6" can go to 5" and still have good camber gain and a raised roll center

Brad
 

George

Goblin Guru
I have been struggling to get the windshield at a better angle for aero dynamics. When installed as designed could not touch the air stream with my arm extended as far up as I could reach. bent the mounting bracket back as far as possible better but still to high. This morning attached windscreen directly to the roll cage. The air stream is now just above the top of my head. This is better for me.

brad
 

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George

Goblin Guru
This is wrong on so many levels. After i put the engine cover panels on attached tuffs for yarn to see the air flow. The air was flowing from the back for the car forward that meant heat from the exhaust was heating up the heat exchanger.
I do have water injection so no damage done. The heat exchanger is now in the full air stream. This does create more wind drag but will try it this way for a while.

Brad
 

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George

Goblin Guru
The rain let up enough to drive the long way home that includes twisty county road. The new windshield angle reduced the engine heat coming from the back forward. Next will reinstall the engine cover and retest.
Tested heat exchanger temp got to 130F with air temp 90F at 8000rpm full power. Will make fences for the heat exchanger to increase efficency. I am sure the potion of heat exchanger will effect top speed.
Installed 125# springs in rear had 150's.
No bad effects seemed to hook up a little better on a hard 2nd gear hard turn with power.

Brad
 

Silverback

Well-Known Member
Yes, It helps direct the air through the heat exchanger. It also increases wind drag.

Brad
What about flipping it so it leans forward? I think you'll get cooling and a bit of downforce since the air will be directed upwards. Might need a scoop/shroud to gain significant downforce. Or a (very) high-mounted rear wing with an incorporated heat exchanger might be an ideal solution.
 
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George

Goblin Guru
Thought about that. The way it is help put air down ward the engine to help fill the backflow from the exhaust. On as designed there is a large air backflow.

Brad
 

Silverback

Well-Known Member
My knowledge of aerophysics is limited, so this is entirely conjecture. I suspect that with the heat exchanger leaned back - and very dependant on the angle of attack - it has the effect of a downward focused nozzle, adding more air velocity below the HE. Despite its winglike orientation, unlike a wing a low-pressure area is created on the front surface, reducing downforce and sucking heat forward into the cabin. With it leaned forward, it would suck air (but not engine heat) behind it and away from the cabin. I'd love to see a tuft test.
 

redline

Well-Known Member
in the end the downforce issue is not relevant unless your doing over 150 MPH. The wings are only for looks and serve no other practical purpose. you can't get enough speed in a 1/4 mile to make them active. the heat exchanger would give you much less than the wing if anything at all.
 

Dre

Well-Known Member
What would be best if we can get one of these things in a wind tunnel or run an FEA for fluid flow.
 

Silverback

Well-Known Member
in the end the downforce issue is not relevant unless your doing over 150 MPH. The wings are only for looks and serve no other practical purpose. you can't get enough speed in a 1/4 mile to make them active. the heat exchanger would give you much less than the wing if anything at all.
The downforce of a wing - particularly mounted low in 'dirty air' - is negligible at legal speeds, if at all. But with proper design and placement of a wing, we may be able to have a significant impact on the flow of engine heat entering the cabin.
 
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