anyone fitted a floor under the engine/box
Discussion
ive been looking at fitting an undertray under the engine and also rear arches or side panels at the side of the engine.
1/tired of cleaning my pride and joy.
2/ there must be so much turbulence at high speed under there.
3/ talking of areo, the rear clan is like a huge parachute with a hole in the centre and must suffer at high speed.
what are the downfalls? ive seen plenty of Ferraris and lambos with enclosed engine bays, has anyone tried it with the ultima yet?
dom
1/tired of cleaning my pride and joy.
2/ there must be so much turbulence at high speed under there.
3/ talking of areo, the rear clan is like a huge parachute with a hole in the centre and must suffer at high speed.
what are the downfalls? ive seen plenty of Ferraris and lambos with enclosed engine bays, has anyone tried it with the ultima yet?
dom
I'm sorry! Closing the bottom of Ultima is a crazy idea. I have a 720 HP LS7 engine. In May 2013 closed the aluminum plate only 50 cm of the engine compartment. Effect?
I went to Italy and Austria at a temperature of 35 º C. fuel to boil. Engine interrupted, stood on the highway and opened the back cover. When cool I moved on. Driving was only possible at night.
Now I have only a 20 cm sheath, and just to be mounted on special holds the air to flow from the bottom force air into the engine compartment. The same holds air cap installed on top of the air supply to the air filter.
In addition, I have two air intakes are made of carbon fiber on the sides of the bonnet. And now is the perfect
I went to Italy and Austria at a temperature of 35 º C. fuel to boil. Engine interrupted, stood on the highway and opened the back cover. When cool I moved on. Driving was only possible at night.
Now I have only a 20 cm sheath, and just to be mounted on special holds the air to flow from the bottom force air into the engine compartment. The same holds air cap installed on top of the air supply to the air filter.
In addition, I have two air intakes are made of carbon fiber on the sides of the bonnet. And now is the perfect
boh.
I closed under the engine with 2 sheets of aluminum delta facts and left open the center.
ie I followed the line of the frame under the engine and I made 2 triangles that enclose the sides freeing up the oil pan and little else
if you follow the line of the square tube frame out the form 2 triangles, of course.
3 years only track day no problem whatsoever
mechanics a little cleaner but I do not know if it benefits aerodynamics ....
I closed under the engine with 2 sheets of aluminum delta facts and left open the center.
ie I followed the line of the frame under the engine and I made 2 triangles that enclose the sides freeing up the oil pan and little else
if you follow the line of the square tube frame out the form 2 triangles, of course.
3 years only track day no problem whatsoever
mechanics a little cleaner but I do not know if it benefits aerodynamics ....
It probably is a bad idea when there is fuel leak but aerodynamically it is an improvement.
Why do all the F1, Indy, IMSA Prototype, etc run flat bottoms? Because it speeds up air flow. I’m guessing, because no MFG’er shows their cars undercarriage.
I’m going to test try some engine floor panels. I had the factory install dzus tabs for the whole aft end.
I’ve fabricated some floor panels with NACA ducts to help evacuate the air flow.
I’ll do some with and without testing. I’ll keep you posted
Why do all the F1, Indy, IMSA Prototype, etc run flat bottoms? Because it speeds up air flow. I’m guessing, because no MFG’er shows their cars undercarriage.
I’m going to test try some engine floor panels. I had the factory install dzus tabs for the whole aft end.
I’ve fabricated some floor panels with NACA ducts to help evacuate the air flow.
I’ll do some with and without testing. I’ll keep you posted
With a flat underfloor, apart from the obvious aero advantages, the other benefit is that you can control airflow and duct cooling air to exactly the area that is needed - which can be much more effective than simply leaving it open and hoping for the best. This is extremely useful and not to be overlooked.
You also need to consider how effective your bodywork is at extracting the hot air - which is generally much more of a challenge - as an example, you could happily run a full flat floor with no temperature issues if you clam was opened up more...
You also need to consider how effective your bodywork is at extracting the hot air - which is generally much more of a challenge - as an example, you could happily run a full flat floor with no temperature issues if you clam was opened up more...
Good comment Jonny. A flat floor improves air flow no question. My Porsche 964RS had a full flat coverage under the gearbox and engine with a small NACA opening just in front of the gearbox. I never had a temperature problem on the track, including long endurance races.
I would like to hear how much improvement to obtained with the two side gills you incorporated on last year's engine clam. I say last year's, as I believe we havn't yet seen the 2014 version yet...
I would like to hear how much improvement to obtained with the two side gills you incorporated on last year's engine clam. I say last year's, as I believe we havn't yet seen the 2014 version yet...

Mine is covered up to the gearbox area, although I tend to run with the centre bit (below the sump) left open.
I am looking at the possibility of adding some more vents in the rear clip so I can fully cover without heat issues, and possibly a fan (I have a spare) behind the gearbox for stationary traffic situations!
I am looking at the possibility of adding some more vents in the rear clip so I can fully cover without heat issues, and possibly a fan (I have a spare) behind the gearbox for stationary traffic situations!
UltimaCH said:
Good comment Jonny. A flat floor improves air flow no question. My Porsche 964RS had a full flat coverage under the gearbox and engine with a small NACA opening just in front of the gearbox. I never had a temperature problem on the track, including long endurance races.
I would like to hear how much improvement to obtained with the two side gills you incorporated on last year's engine clam. I say last year's, as I believe we havn't yet seen the 2014 version yet...
Not yet - shouldn't be too long though!I would like to hear how much improvement to obtained with the two side gills you incorporated on last year's engine clam. I say last year's, as I believe we havn't yet seen the 2014 version yet...

With regards to the side gills - I assume you mean the side scoops? These were one of the actions that we took to reduce fuel temps, and took it from boiling at 90 deg+ to around 45-50 in similar ambient conditions. We weren't monitoring general engine bay temperatures at that point (and we didn't see a significant reduction in AIT). I would also point out that this was only one of the modifications we made to improve cooling.
macgtech said:
With a flat underfloor, apart from the obvious aero advantages, the other benefit is that you can control airflow and duct cooling air to exactly the area that is needed - which can be much more effective than simply leaving it open and hoping for the best. This is extremely useful and not to be overlooked.
You also need to consider how effective your bodywork is at extracting the hot air - which is generally much more of a challenge - as an example, you could happily run a full flat floor with no temperature issues if you clam was opened up more...
Exactly! no point pushing loads of air into the rear clam if it has no where to go! You also need to consider how effective your bodywork is at extracting the hot air - which is generally much more of a challenge - as an example, you could happily run a full flat floor with no temperature issues if you clam was opened up more...

The Noble guys tent to spend more time making holes in the rear clam to let the air out than get more air in. And they run a flat floor.
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