ground effect diffuser?
02-27-2003, 05:56 PM
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splitters and diffusers don't usually add much drag, but make the aerodynamics create more downforce by allowing less pressurized air to slip out. Don't know where you can find one for the TT, although the new EVO carbon front splitter looks like it should help create a little more front downforce.
Dave
Dave
02-27-2003, 07:49 PM
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Turbocharged:
<strong>Does anybody know where i can find them ?
Also what can i do to retain my top speed?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">While I don't have any knowledge of what is specifically available for the 996TT, I can give you some insight into what gains you might obtain, and what it is going to take (in terms of setup).
If you have a really good flat bottom/diffuser plus a mid-height wing that works well with the ground effects + splitter, you could get 1000+ lbs of downforce at ~125 mph. This would be available with a great design. Given you are starting with a street car that involves sigificant compromise, I suspect you could get about half that level. If your car weighs 3500 lbs w/ driver and fuel, and could do 1.2 g's mechanical grip, then the aero would get you up to ~1.4 g's. So, a high speed corner you could take at 125 mph, now can be taken at about 135 mph.
Those are pretty good gains, but what will it take, in terms of set-up? Assuming you can find all the right parts, you WILL need a full wing - a good part of what makes a diffuser work is the help from a rear wing. You will also need the front splitter - a race type, not a street airdam pretending to be a splitter. This also assumes you can get a clean, flat bottom on the car, so the airflow is smooth. Ground effects works better and better as ride height is lowered, up to a point (very low height). You are going to need to run ground clearance in the range of 2-3" or even lower for this stuff to work very well. You also need very stiff springs so the height does not change as you generate downforce and mess up the aero.
All this stuff will add drag, so you will need lots more HP to retain the same top speed.
Bottom line - If you are looking to make your street car faster with aero, there are too many compromises and I doubt you can find anything that will generate more than 100-200 lbs of downforce (or reduced lift). If you are willing to make extreme changes, then you can get some decent benefits if you can find the parts.
Hope this helps.
<strong>Does anybody know where i can find them ?
Also what can i do to retain my top speed?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">While I don't have any knowledge of what is specifically available for the 996TT, I can give you some insight into what gains you might obtain, and what it is going to take (in terms of setup).
If you have a really good flat bottom/diffuser plus a mid-height wing that works well with the ground effects + splitter, you could get 1000+ lbs of downforce at ~125 mph. This would be available with a great design. Given you are starting with a street car that involves sigificant compromise, I suspect you could get about half that level. If your car weighs 3500 lbs w/ driver and fuel, and could do 1.2 g's mechanical grip, then the aero would get you up to ~1.4 g's. So, a high speed corner you could take at 125 mph, now can be taken at about 135 mph.
Those are pretty good gains, but what will it take, in terms of set-up? Assuming you can find all the right parts, you WILL need a full wing - a good part of what makes a diffuser work is the help from a rear wing. You will also need the front splitter - a race type, not a street airdam pretending to be a splitter. This also assumes you can get a clean, flat bottom on the car, so the airflow is smooth. Ground effects works better and better as ride height is lowered, up to a point (very low height). You are going to need to run ground clearance in the range of 2-3" or even lower for this stuff to work very well. You also need very stiff springs so the height does not change as you generate downforce and mess up the aero.
All this stuff will add drag, so you will need lots more HP to retain the same top speed.
Bottom line - If you are looking to make your street car faster with aero, there are too many compromises and I doubt you can find anything that will generate more than 100-200 lbs of downforce (or reduced lift). If you are willing to make extreme changes, then you can get some decent benefits if you can find the parts.
Hope this helps.
02-28-2003, 04:13 PM
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On a World Challenge Corvette, we get about 200lbs front and 400lbs rear downforce from using a 4" splitter with an integrated converging panel under the nose and a 69" wide wing (approx 9" chord) on the rear. However, as mentioned above, to get these type of gains, it nearly doubles the drag over a lift-producing street car.
Dave
Dave
03-03-2003, 01:49 PM
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by y2khardtop:
<strong>On a World Challenge Corvette, we get about 200lbs front and 400lbs rear downforce from using a 4" splitter with an integrated converging panel under the nose and a 69" wide wing (approx 9" chord) on the rear. However, as mentioned above, to get these type of gains, it nearly doubles the drag over a lift-producing street car.
Dave</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Thanks for that info - it is really interesting to know. Good luck this year.
<strong>On a World Challenge Corvette, we get about 200lbs front and 400lbs rear downforce from using a 4" splitter with an integrated converging panel under the nose and a 69" wide wing (approx 9" chord) on the rear. However, as mentioned above, to get these type of gains, it nearly doubles the drag over a lift-producing street car.
Dave</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Thanks for that info - it is really interesting to know. Good luck this year.
