Full Under Floor/Diffuser
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From: St. Louis
Not to point out the obvious in this interesting discussion but:
The 430 Challenge cars (that you could probably drive over your drive way) could only be producing handling advantages from their underbody aero due to the fact that Ferrari has a wind tunnel, last time I checked, which as Olsen points out in the begining is neccessary to try and tackle an effective under body aero package on any car. Wihtout it, how do you effectively measure gains and more importantly make changes to the design to reduce lift and produce a signifigant amount of downforce?
This is where F1 hung around from the early 70's until 87 when Lotus developed the first active ride car and eventualy the early 90's when FAS was the norm for the top teams. The aerodynamicists hard work in the wind tunnel was rendered ineffective at certain corners of certain tracks were the car would pitch and roll - which the wind tunnel could not simulate. The solution was to make the body as flat as possible under any circumstance taking full advantage of the (now banned) full flat bottoms, rear diffusers, and wings. And then it started failing during sessions and driver crashed and it was banned
THe group C cars of the 80's, or Tunnel cars as Mr. Garrison pointed out, took a different aproach to acttualy use a network of tunnels integrated throughout the bottom and inner workings of the body to produce massive amounts of downforce without a recognizeable front wing or splitter and a relatively low and flat rear wing placed far behind the body (for stability?). In one of my old autoweeks in the bathroom from 90 they report of one of the Toyota Group C cars producing a METRIC TON OF DOWNFORCE at 150mph, probably justifying the need for over 1000hp in race trim.
So again I ask how would a full flat bottom for our cars be effective wihtout wind tunnel testing and a fairly extensive track test? I wouldn't want anyone on here to be a 130mph guinea pig considering none of us get paid to track our S2000's. Reducing lift is something I am interested in as I and other owners have "felt" at over 100mph thorugh a corner, but this can be overcome with just a wing right?
The 430 Challenge cars (that you could probably drive over your drive way) could only be producing handling advantages from their underbody aero due to the fact that Ferrari has a wind tunnel, last time I checked, which as Olsen points out in the begining is neccessary to try and tackle an effective under body aero package on any car. Wihtout it, how do you effectively measure gains and more importantly make changes to the design to reduce lift and produce a signifigant amount of downforce?
This is where F1 hung around from the early 70's until 87 when Lotus developed the first active ride car and eventualy the early 90's when FAS was the norm for the top teams. The aerodynamicists hard work in the wind tunnel was rendered ineffective at certain corners of certain tracks were the car would pitch and roll - which the wind tunnel could not simulate. The solution was to make the body as flat as possible under any circumstance taking full advantage of the (now banned) full flat bottoms, rear diffusers, and wings. And then it started failing during sessions and driver crashed and it was banned
THe group C cars of the 80's, or Tunnel cars as Mr. Garrison pointed out, took a different aproach to acttualy use a network of tunnels integrated throughout the bottom and inner workings of the body to produce massive amounts of downforce without a recognizeable front wing or splitter and a relatively low and flat rear wing placed far behind the body (for stability?). In one of my old autoweeks in the bathroom from 90 they report of one of the Toyota Group C cars producing a METRIC TON OF DOWNFORCE at 150mph, probably justifying the need for over 1000hp in race trim.
So again I ask how would a full flat bottom for our cars be effective wihtout wind tunnel testing and a fairly extensive track test? I wouldn't want anyone on here to be a 130mph guinea pig considering none of us get paid to track our S2000's. Reducing lift is something I am interested in as I and other owners have "felt" at over 100mph thorugh a corner, but this can be overcome with just a wing right?
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From: Toronto
Originally Posted by JackOlsen,Sep 8 2008, 09:47 AM
The Ferrari with two wheels up probably isn't -- at that moment -- generating any downforce at all with its underbody kit. Aside from the belly being at a severe angle, it's a low speed corner. Without really serious airflow, channels and a diffuser don't do anything.
At speed, though, the setup is probably very effective.
The same pieces on a street-driven car would be higher up and much more vulnerable to body roll, and probably wouldn't be very effective at all.
What I see on Derek's car are front and side curtains (and probably an aggressive splitter lip). All of that stuff will definitely help at the track -- but it's not the same thing as a true underbody setup. Keeping air from getting under the car creates a lower-pressure zone which pulls the car down. An underbody treatment is something else: it uses compression, channels and a diffuser to manage air speed (and density, sort of) to create a low pressure zone.
You can't have both, ultimately. If your front/splitter comes down too low, you won't get the high volume of air under the car that you need for an underbody package to work. You can see the elevated intake on cars with functional underbody setups. Ultimately, an underbody setup is capable of much more than air curtains and a deep splitter, but it's much less flexible in terms of its operating environment -- meaning distance from the pavement and position relative to that pavement. What Derek has is more practical for a production car. (Although he's not going to make it over the curb and into the driveway, is he?)
At speed, though, the setup is probably very effective.
The same pieces on a street-driven car would be higher up and much more vulnerable to body roll, and probably wouldn't be very effective at all.
What I see on Derek's car are front and side curtains (and probably an aggressive splitter lip). All of that stuff will definitely help at the track -- but it's not the same thing as a true underbody setup. Keeping air from getting under the car creates a lower-pressure zone which pulls the car down. An underbody treatment is something else: it uses compression, channels and a diffuser to manage air speed (and density, sort of) to create a low pressure zone.
You can't have both, ultimately. If your front/splitter comes down too low, you won't get the high volume of air under the car that you need for an underbody package to work. You can see the elevated intake on cars with functional underbody setups. Ultimately, an underbody setup is capable of much more than air curtains and a deep splitter, but it's much less flexible in terms of its operating environment -- meaning distance from the pavement and position relative to that pavement. What Derek has is more practical for a production car. (Although he's not going to make it over the curb and into the driveway, is he?)
A low pressure zone under the car from under car air mgt. can create tremendous downforce and unlike wings, does not have a significant drag penalty. This is one reason why the IMSA GTP cars back in the early 90's could create more downforce than even F1 cars...the designers had so much undercar surface area to play with.
Think of a suction cup with a vacumn (low pressure zone) underneath and you get an idea of how much force can be generated by this.
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From: SoFlo
Originally Posted by tnguyen0567,Sep 12 2008, 01:44 PM
Thanks Billy for visiting Password JDM yesterday and providing your expertise and input.
Tan
Tan
Thank you and Steven for having me over. You guys have quite an impressive operation and a lot of amazing projects and products. I look forward to working with you and Password JDM in the future.
Billy
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