Anyone thought of Full Underbody Tray for max downforce?
Discussion
OmeyHomey said:
Hey guys,
Just curious if anybody has thought about running a true underbody tray across the entire length of the car to improve downforce significantly. Anybody tried it?
What's wrong with the current level of downforce?Just curious if anybody has thought about running a true underbody tray across the entire length of the car to improve downforce significantly. Anybody tried it?
What method have you used to determine that a significant improvement can be made?
Steve
I have a complete undertray and rear diffuser as made for me by Phoenix Motorsport of Accrington Lancs.
The downforce is directly proportionate to the speed, and the car will of course benefit from being lowered to increase this, but thats not to say theres no difference without lowering.
I have it set at standard height,and it does seem more planted.
I suggest those able to give the most accurate assesment of any benefit are those who have such a mod in place.
Ring Oli or Gregg at Phoenix for a chat about it. They know their stuff as they have worked in preparing cars for various formulas for 30 yrs. (01254 384071)
The downforce is directly proportionate to the speed, and the car will of course benefit from being lowered to increase this, but thats not to say theres no difference without lowering.
I have it set at standard height,and it does seem more planted.
I suggest those able to give the most accurate assesment of any benefit are those who have such a mod in place.
Ring Oli or Gregg at Phoenix for a chat about it. They know their stuff as they have worked in preparing cars for various formulas for 30 yrs. (01254 384071)
Stig said:
Not only that, but IIRC to really get significant improvements and to take advantage of 'ground effect' you would have to run the car much lower than standard.
Budala - trust me, advice is always plentiful from those who stand to make a few bucks from it
I took advice from a specialist (he has worked for Winfield for 25 years and still prepareBudala - trust me, advice is always plentiful from those who stand to make a few bucks from it
Alain Prost'car) and he has nothing to sell me !
I bought my complete underbody to Grasser Racing (Austria) and "my" french specialist told me that this underbody
will improve the car's performance, even without lowering the car...
He said it will make the same difference than between normal tyres and slicks !
Did your specialist tell you what sort of downforce to expect, how to ensure the car remained safely balanced at high speed and what you would need to do to the suspension to control the ride height and attitude? Underbody aerodynamics can be extremely sensitive to ride height and pitch changes and if the undertray does work you could find the effects varying dramatically as the suspension moves.
GreenV8S said:
Did your specialist tell you what sort of downforce to expect, how to ensure the car remained safely balanced at high speed and what you would need to do to the suspension to control the ride height and attitude? Underbody aerodynamics can be extremely sensitive to ride height and pitch changes and if the undertray does work you could find the effects varying dramatically as the suspension moves.
His job is to prepare cars except engines. He is specialised in suspensions and chassis, weight and height...But sorry, it's very hard for me to explain that in english. My english is too poor with such technical details
in mechanic. It's allready difficult for me in french !
I'm always willing to learn but how did you get over the lowered floor pan (Its a pet hate of mine)....
I got rid of the lowered pan in my new car and got better head room in other ways, plus have a full fixed front and side splitters, so the car is flat from front to rear and only has cut outs where the wheels are...
Any pictures of your car ??
I got rid of the lowered pan in my new car and got better head room in other ways, plus have a full fixed front and side splitters, so the car is flat from front to rear and only has cut outs where the wheels are...
Any pictures of your car ??
About my enquiry weither this underbody is difficult to install or not, Dr Grasser
answered it was really easy and will send me instructions.
You can visit their website too (see the shop) : www.grasser-racing.com
answered it was really easy and will send me instructions.
You can visit their website too (see the shop) : www.grasser-racing.com
A curved(convex)tray might be better then a flat floor at accellerating airflow under the car. In fact you could have an adjustable plank running across the centre of the car and probably get good results. You would need a means of rotating it to experiment with a variety of depths under the car but with some thought it could be diy and may yield measurable results and allow development.
Edited by Boosted LS1 on Tuesday 30th December 17:24
As a post script I just spoke to Oli at Phoenix, and he will be willing to make and supply a rear section (bulkhead backwards) and diffuser unit for the Ultimas.
Heres a couple of pics: (first picture shows the unit against the wall).
They also can make the front splitter & Nascar style struts for anyone who may be interested.
Heres a couple of pics: (first picture shows the unit against the wall).
They also can make the front splitter & Nascar style struts for anyone who may be interested.
Edited by Wilder on Tuesday 30th December 23:13
There is no doubt in my mind that a proper complete undertray would improve the airflow on the Ultima signficantly. But here are 2 majr issues.
Firstly the lowered floor pans (if they are fitted to your car) would need to be removed and then you would need to find another way of cooling the engine bay (most significantly the gearbox) as most of the airflow through the engine bay comes from under the car.
Firstly the lowered floor pans (if they are fitted to your car) would need to be removed and then you would need to find another way of cooling the engine bay (most significantly the gearbox) as most of the airflow through the engine bay comes from under the car.
This is why I considered the bowed option which would use the Bernoulli principle and accelerate the air flow under the car. Couple that with an extractor/diffuser and you could still guide air through the gearbox region and exit the air around the exhaust pipe outlets.
http://en.wikipedia.org/wiki/Bernoulli's_principle
It's similar to having a wing section but upside down except the air would be trapped between the wing and the road. I wonder if this is how those Caspian sea monsters worked?
http://en.wikipedia.org/wiki/Bernoulli's_principle
It's similar to having a wing section but upside down except the air would be trapped between the wing and the road. I wonder if this is how those Caspian sea monsters worked?
Bernoulli, wings, sails, carb venturis and many objects profile all work on the same principle when producing lift. If used under a car they would need to be highly adjustable/developed to be effective and not dangerous. Any wing has limitations and needs to be adjustable in order to work effectively over its range of speeds and operating conditions. Fixed wings, spoilers etc fitted to cars are a compromise and really only give accurate results over a limited speed range. Things get quite exciting when subjected to 150mph+ airspeeds!
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