What is the solution to lean fuel/boiling swirlpot on LS7

[mt308]

georg said:

Hi All
I celebrated all this several years ago. I solved the problem eventually
1-led more outside air with a strong flow through the engine compartment in the lower and upper parts
2-installed refrigeration with a fan
3 - I have installed two fans in the engine compartment with the air supply from the outside / similarly to the Porsche /. I turn on manually during every stop in the traffic jam.
Four more small modifications to the engine cover

from now on I have been driving to Italy for 4 years in July and August. I often stand in traffic jams even after several kilometers. There was never cavitation of fuel.
This problem of cavitation ended for me finally.
Regards
georg

Thanks Georg

Under 2, where you say refrigeration fan, can I check what you mean? Do you have photos?

Mark

[georg]

Yes, I have photos. Showing where there are two fans that capture air from the outside, and fuel coolers with a fan. It all works perfectly well for about 4 years.
Georg

[mt308]

georg said:

Yes, I have photos. Showing where there are two fans that capture air from the outside, and fuel coolers with a fan. It all works perfectly well for about 4 years.
Georg

Wow - quite a modification! Thanks for that, I will try some further insulation to the swirl pot first.

Mark

[mt308]

Fuel again! I have now fitted a fan at the back of the clam to come on with the rad fans. This kicks out a huge amount of heat and seems to have solved traffic overheating issues.

However I hooked up a temp gauge to my fuel swirl pot and can now see that the temperature of the swirl pot goes up and up when driving along at 70mph (I.e. with good airflow) It got to about 56C then the car felt hesitant (my guess cavitation). I wasn’t expecting this as I thought my issues were in traffic only. Am now wondering if the fuel pipes and filter are too close to the water pipes which are transferring heat.

Good news on the fan solution though - the temp actually came down a little when I left it running for 10 mins in the drive with the fans on. Thanks to Andy for his neat solution and custom made fan bracket. Phenomenal heat out the rear now, even better when air con running.

Mark

[deadscoob]

Any pics?

[mt308]

deadscoob said:

Any pics?

[mt308]

[200Plus Club]

No disrespect but the bracket looks a little like thrown together dexion racking. Now you've proved it works as a fix a nicely welded alloy frame perhaps or something tidied? I can't weld neatly myself I should point out but plenty of people can!
(No offence intended just an observation)

Edited by 200Plus Club on Tuesday 17th July 09:23

[georg]

Hi,
this fan in the back is some idea, but it is more important to bring outside air under the engine cover. I made two air grips on the engine cover on the left and right side. Under the cover are installed two small fans pulling air from outside. Pay attention if at the moment when you stop the vehicle and insert your hand to unlock the upper lock, under the cover should be only warmth and not definitely hot. My modifications give me an absolute guarantee ... no cavitation even at the highest temperatures in Italy.
Regards
Georg

[BogBeast]

georg said:

Hi,
this fan in the back is some idea, but it is more important to bring outside air under the engine cover. I made two air grips on the engine cover on the left and right side. Under the cover are installed two small fans pulling air from outside. Pay attention if at the moment when you stop the vehicle and insert your hand to unlock the upper lock, under the cover should be only warmth and not definitely hot. My modifications give me an absolute guarantee ... no cavitation even at the highest temperatures in Italy.
Regards
Georg

I like the roof 'snorkel' I always thought that extending it over the roof and across the top of the screen had the best chance of picking up some high-pressure air.

I am no aerodynamicist but I always felt that scoops in the rear clip were possibly not very useful due to being in what I suspect is a low-pressure area; likewise, they side scoops. Trouble is. full sized wind tunnels are hard to come by to test...

[Steve_D]

BogBeast said:

........ Trouble is. full sized wind tunnels are hard to come by to test...

Do your own. Tape some wool threads where you want to check air flow then mount a go-pro camera and go for a drive.

Steve

[BobE]

Steve_D said:

BogBeast said:

........ Trouble is. full sized wind tunnels are hard to come by to test...

Do your own. Tape some wool threads where you want to check air flow then mount a go-pro camera and go for a drive.

Steve

If you look at the MIRA wind tunnel photos using wool tufts you can see the airflow stays attached over the roof of the car and hence there would be a dynamic pressure at the inlet to the air intake in the rear clam. However I suspect things are much more complex than that as the diffuser created by the rake angle of the floor suddenly ends in the engine bay so it must be a little uncertain what level of reduced pressure there is at the rear outlet on the vertical face of the bodywork. Looking at the airflow along the sides of the car on the MIRA test the side vents appear to do little when the car is moving but I suspect the are very usefully when the car is stationary.

[georg]

Gentlemen, the air grip on the roof has two tasks.
1- transmits non-dispersed air to the air filter
2- support for ventilating the engine compartment.
Someone will ask how he can accomplish these two tasks if under the cover the air flows through a closed tunnel.
In the tunnel, after the air flow analysis, two rectangular holes are made with a small obstacle that directs the air part down to the engine and the larger part of the air to the filter. The air flow was physically examined by my fellow engineers from the Warsaw airport.

The side air grips placed on the cover fulfill their task precisely in the movement of the vehicle. Theoretically tested.
Regards

[confusionhunter]

Nice mods!

Very very important to note the uprated aerocatches for the rear clam. For anyone thinking about these mods.... If you mess with the aero on the rear clam you Absolutely need to uprate the catches. The standard catches are for standard clams and not for buttoning down a clam that generates any kind of lift at speed which intake vents will absolutely do. The impacts of not doing this could be very serious.