Front Splitter ??
Discussion
Aint got one -- never had one ! While I understand the aerodynamic principles concerning splitters and the like ( aircraft engineer) does the Chim really need one and just how effective are the ones described in previous posts. I've never had high speed instability problems apart from duff factory shocks that is , it always feels pretty well planted even at 140 ish (private road) I'd be interested to hear what the racers think..........
Nick..........
Nick..........
Nick,
Can't say I've noticed stability - OR - bonnet lift issues.
But I refitted a 30mm plastic angle (B&Q about £4.50!!) to replace original which had been ripped off and definitely had a reduction in engine temp on the move....lowered by 5-10 degC approx. Effective for not a lot of dosh!
Nick
Can't say I've noticed stability - OR - bonnet lift issues.
But I refitted a 30mm plastic angle (B&Q about £4.50!!) to replace original which had been ripped off and definitely had a reduction in engine temp on the move....lowered by 5-10 degC approx. Effective for not a lot of dosh!
Nick
Nick,
Can't say I've noticed stability - OR - bonnet lift issues.
But I refitted a 30mm plastic angle (B&Q about £4.50!!) to replace original which had been ripped off and definitely had a reduction in engine temp on the move....lowered by 5-10 degC approx. Effective for not a lot of dosh!
Nick
Can't say I've noticed stability - OR - bonnet lift issues.
But I refitted a 30mm plastic angle (B&Q about £4.50!!) to replace original which had been ripped off and definitely had a reduction in engine temp on the move....lowered by 5-10 degC approx. Effective for not a lot of dosh!
Nick
I bought one for my old Chimaera and noticed both the lower engine temperatures and also felt more planted at 80 - 90+.
Mine was metal bought via TVR parts supplier as the original fit. I fitted it using aluminium rivets to ensure they snapped before the bodywork did when the inevitable happened and it was caught on a speed hump or kerb...
Mine was metal bought via TVR parts supplier as the original fit. I fitted it using aluminium rivets to ensure they snapped before the bodywork did when the inevitable happened and it was caught on a speed hump or kerb...
dings said:
where about does it go, what is it you got from BQ and used
I got a 30mm right angled black plastic edging strip from my local B&Q, cost about £4.50. Cut it to length and silicon fixed it to where I could see remnants of original.I'm convinced it's lowered my 'running' temps - now typically 75 degC even on the French M'ways coming back from LeMans in June (Monday was pretty warm).
I thought for £4-5 its got to be worth a try.
Nick
Ta for that guys,I've got no witness marks to follow so a pic of the wee beastie would be appreciated if anyone out there has one. I suppose its worth fitting one to see if it has any effect,I'd certainly like to see a reduction in temp , nothing ventured and all that..............
Nick..............
Nick..............
[quote=f@-pots]Ta for that guys,I've got no witness marks to follow so a pic of the wee beastie would be appreciated if anyone out there has one. I suppose its worth fitting one to see if it has any effect,I'd certainly like to see a reduction in temp , nothing ventured and all that..............
Just take it back as far as the fibreglass goes then 6 rivets will hold it also a bead of silicone should help it stay should you hit a bump.
Just take it back as far as the fibreglass goes then 6 rivets will hold it also a bead of silicone should help it stay should you hit a bump.
V8 Animal said:
f@-pots said:
Ta for that guys,I've got no witness marks to follow so a pic of the wee beastie would be appreciated if anyone out there has one. I suppose its worth fitting one to see if it has any effect,I'd certainly like to see a reduction in temp , nothing ventured and all that..............
Just take it back as far as the fibreglass goes then 6 rivets will hold it also a bead of silicone should help it stay should you hit a bump.
Yep,thats what i did Just take it back as far as the fibreglass goes then 6 rivets will hold it also a bead of silicone should help it stay should you hit a bump.
with the same bit of B&Q special 
This topic is of interest to me as well, not the small strip on that was fitted originally but a proper splitter 50mm off the ground extending beyond the nose. Like others say I have no stability problems but the text books seem to indicate that reducing air flow under the car not only reduces lift but reduces drag. The lumpy underside is a lot more “draggy” that the roof or sides. However my concern is if adding a proper splitter gets the front planted does the rear become less planted without the corresponding diffuser, has any body tried it ? The benefit I am looking for is straight line speed.
OK steve, the front splitter may well direct the airflow away from all the lumpy bits at the front thus reducing 'form' drag in that area, however all the race cars I have worked on had a flat underside from the nose through to just forward of the rear driveline and as you have mentioned , a rear diffuser. The first two bits will give you a straight line speed advantage as they are not designed to give downforce (front splitter only ,not including fwd undertray)The rear diffuser however is designed to give large amounts of downforce,(dependant on design efficiency) which has a considerable aerodynamic drag penalty .Great for corners but not for straight line speed! Basicaly it'll slow you down, plus if the front and back end aren't balanced aerodynamically you will have some pretty weird handling characteristics which will change dependant on speed so you're not going to make up time on the twisty bits. Thats why so much time and money is spent by the big boys in wind tunnels trying to achieve that balance.
Still, it might be a bit of fun trying and I too would be interested to see if a few simple mods might improve aerodynamic efficiency, I reckon flattening the underside as much as poss is the first port of call and probaly the easiest and cheapest.
Whaddya reckon??
Still, it might be a bit of fun trying and I too would be interested to see if a few simple mods might improve aerodynamic efficiency, I reckon flattening the underside as much as poss is the first port of call and probaly the easiest and cheapest.
Whaddya reckon??
steve-V8s said:
This topic is of interest to me as well, not the small strip on that was fitted originally but a proper splitter 50mm off the ground extending beyond the nose. Like others say I have no stability problems but the text books seem to indicate that reducing air flow under the car not only reduces lift but reduces drag. The lumpy underside is a lot more “draggy” that the roof or sides. However my concern is if adding a proper splitter gets the front planted does the rear become less planted without the corresponding diffuser, has any body tried it ? The benefit I am looking for is straight line speed.
What straight line speed are you after on a private road as i have one fitted and i can take my hand of the wheel at X speed and it goes in a straight line.V8 Animal
This is actually on a Griff not a Chim but basically the same thing. It seems to me that beyond the engine and ahead of the rear suspension the car is by comparison to a lot of stuff already fairly flat. Boxing in the chassis rails looks easy and the exhaust fixing plate could do without the return hanging down all the way round it. My plan is to take a splitter right back to the front cross member so that should help launch the air past the sump. It would probably also be good to provide an exit for air entering the engine bay via the rad other than under the car probably that needs additional holes in the bonnet. Beyond the engine the main restrictive areas seem to be the rear anti roll bar and the exhaust pipes. The pipes can simply be brought out directly from the box alongside each other rather than splaying out. One thought about the roll bar is to put a profiled plate over it. That would create a venturi effect and after that the rear of the Griff is almost Diffuser shaped anyway all be it without the strakes.
My concern is that I already have the car handling fairly neutrally in fast sweeping corners, if anything it is the tail that tends to breakaway. People seem to rave about how a splitter reduces understeer. What I don’t what to do is get the front more planted when I don’t need it at the expense of losing the back.
How does the Diffuser add drag ? I thought the idea was reduce the flow with the splitter and then to restrict what flow there is around the half way point so as to accelerate it and then decelerate it again as it exits to meet with the flow behind at about the same speed thus reducing flow separation and drag. I can understand that the splitter adds drag but hopefully less that it gets rid of.
My concern is that I already have the car handling fairly neutrally in fast sweeping corners, if anything it is the tail that tends to breakaway. People seem to rave about how a splitter reduces understeer. What I don’t what to do is get the front more planted when I don’t need it at the expense of losing the back.
How does the Diffuser add drag ? I thought the idea was reduce the flow with the splitter and then to restrict what flow there is around the half way point so as to accelerate it and then decelerate it again as it exits to meet with the flow behind at about the same speed thus reducing flow separation and drag. I can understand that the splitter adds drag but hopefully less that it gets rid of.
One thing to look out for if you do fit an undertray is exhaust and transmission cooling. You will almost certainly need to fit 'box and diff coolers and provide extra protection from the exhaust heat to stop it destroying the stuff around it. Smooth underbody trays and extractors rely on having lots of smooth air flow under the car - so raise the nose and smooth the underside off rather than have a square dam there. You will also need to limit or take account of inflow from the sides in order for it to work effectively. Also bear in mind that underbody aerodynamics tend to be massively sensitive to ride height and attitude, and if you get any significant downforce you should be prepared for the magnitude and center of effort to fluctuate wildly.
Cooling is a good point, however as it is a hill climb car and does circa 1km runs in anger I am not overly worried about that although it is worth bearing in mind as it does get driven to the hills. When you say raise the nose what do you mean ? most splitters and air dams seem to go very nearly to ground level.
To address the increase in drag question , as with any venturi, air passing through will accelerate, the maximum speed of this air usually co enciding with the narrowest most restricted point (centre of pressure). This acceleration causes a reduction in air pressure which sucks the back of the car down .We call it 'downforce' the aircraft boys will call it 'lift'.There are aerodynamic trade offs due to skin friction , vortecies etc which result in an increase in aerodynamic drag 'induced drag' plus an increase in rolling resistance as there is effectively an increased weight penalty. If you want more obvious proof just look at wing set ups for fast and slow tracks in F1 and the like, lots of downforce for twisty tracks but as little as possible for tracks with long straights.
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