AZMoto #245 ext-track - 09 SS TC

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G Atsma

Goblin Guru
AZmoto said:
The size of this thing makes me think it might make a great front wing when it's no longer needed in the back.
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When HAS it been needed in back? The car is heavily rear-weight-biased already; no extra downforce needed.
It would look cool across the front, where it can do some good
 
Fozda

Fozda

Goblin Guru
G Atsma said:
When HAS it been needed in back? The car is heavily rear-weight-biased already; no extra downforce needed.
It would look cool across the front, where it can do some good
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Is that based on experience or just speculation? I was under the same impression until I decided to try it because it's so cheap and picked up a whole second on a 40 second course that I've been running at for years and have done almost a dozen events with in the Goblin. The only thing that changed between events was the wing.
 
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G Atsma

Goblin Guru
There is NO speculating weight distribution when you have a tube-frame skeleton chassis with the full drivetrain AND fuel tank in the rear, both passengers TOWARDS the rear, and the small battery and radiator holding down the front.
It doesn't take a masters in mechanical engineering or physics to figure out what any semi-literate but observant teenager can see. If after all the above, a rear wing improved the track times, I think other issues were in play. See what happens with the wing up front. Can you say, "improved balance"?
 
Ross

Ross

Goblin Guru
Yes the Goblin's rear has 1100 pounds and the front has 600 pounds (with a driver in the seat).
But I spent a year working on getting the rear to hook up with the ground. 4 different sets of tires, different springs, shock settings, different wheel alignments, even a Quaife differential. It is easy to kick the rear end out, even thou it has all that weight on it. I finally have my car sorted, but I do believe downforce will help (I haven't played much with aero yet).

With the extra weight in the rear, when cornering, the rear will need extra traction (compared to the front). So it makes sense to me that rear downforce would aid in rear traction, and faster lap times.
 
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Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
Before getting our shorts wadded up, let's take a minute to step back and remember we are all building unique vehicles. What works for one Goblin may not be as effective on another Goblin. :D
Fozda has good experience with adding a wing to his Goblin for apparent added traction in the type of driving he is doing - which is good for his suspension setup (springs, ride height, swaybar, etc.). Others on the forum have stated that a rear wing made their front end too light - assuming a high speed. Those who have mounted a front wing state it helps great to reduce front end lift and improve turning performance. Next thing we know Fozda will be joining the front wing crowd - it took him a while to warm up to the rear wing crowd. ;):p
Aerodynamics is part magic to go with the science and your suspension set up will be be a big factor for how well any aero add-ons will effect a Goblins handling. Yes, aero can help compensate for the rear weight bias of the car, but we still have the laws of physics to keep us looking for more ways to improve. :cool:
 
S

Scott #321

Well-Known Member
Nothing beats good ole trial and error to find out what works for you. Even in so called one design racing drivers can have significantly different setups on their cars based on their driving style. I will be looking for rear traction assistance this winter for next season autocross.
 
Rttoys

Rttoys

Goblin Guru
I have **** good rear traction (now), but at the last autocross there was a left/right/left on camber/off camber that disrupted the chassis pretty well and made the ass end light as hell. Even though i have a good setup for myself, there’s still work to be done. They are all the same, but all different. Find your magic combination and run with it.
 
Waterdriver

Waterdriver

Goblin Guru
G Atsma said:
There is NO speculating weight distribution when you have a tube-frame skeleton chassis with the full drivetrain AND fuel tank in the rear, both passengers TOWARDS the rear, and the small battery and radiator holding down the front.
It doesn't take a masters in mechanical engineering or physics to figure out what any semi-literate but observant teenager can see. If after all the above, a rear wing improved the track times, I think other issues were in play. See what happens with the wing up front. Can you say, "improved balance"?
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So your saying Porsche, Ferrari and others have it all wrong? Interesting.
high_911_rsr_2019_model_year_2019_porsche_ag_1_web.jpg
195126-cgt-Ferrari_GT3_EVO_2020.jpg
 
G

G Atsma

Goblin Guru
Waterdriver said:
So your saying Porsche, Ferrari and others have it all wrong? Interesting.
View attachment 29642
View attachment 29643
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No. Porsche, Ferrari, et al... have bodies that affect aerodynamics in many different ways, many of them requiring wings.
YOU have an assemblage of tubes and a drivetrain that just do a mishmash of vortices that neither lift nor plant the car. You DO have far more weight over the rear than the front, effectively planting the rear, but possibly requiring a wing on the front. But wings LOOK far cooler when over the rear, and here you are.
 
AZmoto

AZmoto

Well-Known Member
Well the first test drive is complete. It wasn't much of a test drive but it did make it onto the street and back. Verified that the shifter, new clutch, brakes and parking brake are all working. Next I have to fit all of the bodywork and get started on the title/registration process.

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