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Nosecone air vents


Mole

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Having fitted TBs and an airbox to replace the standard K-series inlet plenum, the air filter is now positioned inside the nosecone, directly behind the radiator instead of by the pedal box as it was formerly. As a result it is sitting in an enclosed area in the air stream being heated by the radiator! The obvious way of getting cold air to the inlet is to cut a vent in the nosecone - has anyone done this? The only example I've seen is the Swiss Kumschick 2lt turbo which has vents to feed the oil cooler - I'm surprised no-one else seems to have done something similar.

 

SV 52 CAT - moles fly -

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I've recently done the same mod. The air filter may be inside the nosecone, but there are considerable gaps around the radiator and don't forget there is good airflow though that area.

 

I'm going to monitor my inlet air temp from the laptop while I'm driving, but don't anticipate any problems with hot air.

 

Maybe stationary with the engine running might raise the air inlet temp., but I don't plan on doing much of that 😬

 

BRG Summertime Brooklands SV 😬 It is only with the heart that one can see rightly; what is essential is invisible to the eye. (Antoine de Saint-Exupery)

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Thanks guys.

 

Tony - I've fitted temperature sensors to measure external air temp and the temp inside the air box. I'm regularly seing an inlet air temp 15 deg + over external air temperature. This is the reason I'm looking at ways of getting cooler air to the air filter and into the airbox.

 

SV 52 CAT - moles fly -

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Hmmm - that would be worth correcting, did't realise it would be that big a discrepancy.

 

I'll have to hurry-up and check mine 😬

 

BRG Summertime Brooklands SV 😬 It is only with the heart that one can see rightly; what is essential is invisible to the eye. (Antoine de Saint-Exupery)

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I have yet to verify this, but my colleague in the Met. department says that a 15 deg C higher temp. will give an approximate 7% to 8% decrease in air density 🙆🏻

 

BRG Summertime Brooklands SV 😬 It is only with the heart that one can see rightly; what is essential is invisible to the eye. (Antoine de Saint-Exupery)

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Thats amazing, I did this mod at the weekend. I have yet to cut through the nose cone though. If you want pictures drop me an email to richarde@peter-cook-int.co.uk

 

Cost for all parts was about £20 but you can judge for yourself how it looks.

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Peter Cox has made up a specific guide for his sv to allow cold air direct to the tb's. He has also moved the rad over slightly.

 

I'll have a word with one of his locals and see if we can dig out a pic or two *thumbup*

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Thanks mav, that would be great.

 

I was considering making an internal shield from a flat piece of material starting at the top of the radiator, rearwards to pass beneath the air filter mounted on the front of the airbox.

 

I think this might prevent the heated airflow from the radiator interfering with the air being drawn into the air filter from the nosecone - maybe 😬

 

Might be preferable to fitting a NACA duct in the nosecone.

 

Just checked a textbook and the decrease in air density due to temperature is approximately 1% per 3 deg C, making 15 deg give an approximate reduction of 5% air density.

 

This relates to Dave Jackson's figure 😬

 

BRG Summertime Brooklands SV 😬 It is only with the heart that one can see rightly; what is essential is invisible to the eye. (Antoine de Saint-Exupery)

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you could mount a temp sender in the airbox so you can see the temp. Or if you have an emerald then just plug in a laptop and see what it says. Then run with nose/bonnet on and nose/bonnet off and see what the difference is. I plan to do this to see the difference and then use a bit of ali (12" x 12" or so) to duct air over the rad and then into the filter.

 

And yes - 10C giving 3% is the figure. That could easily be 20 bhp for a powerful 7 between winter and summer on the continent.

 

FWIW I was getting 68C in my airbox at emerald, a bit of cardboard to shield the filter dropped that to 45C. They've got aircon there as well now (it was 30C in there when we did mine) so that's another 20C cooler. 20C gain, 190bhp, takes me over 200...

 

HOOPY R706KGU Hoopylight R

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tony i've talked with a friend who's an F-1 aerodynamics designer regarding doing something similar to our SV. she said that we'd be better taking the air that is rammed into the front grille than to add an external blister pack, as we already have a larger projected surface area in front with the SV. as air is being "rammed in/around" to the radiator, we have plenty of room to put the blister's in *backwards* in the cone and get what we desire. FWIW i await your temperature measurements.

 

Steve B

Big Black Beast^3 SV VHPD

USA 2005: How the West Was Driven

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Makes a lot of sense to me Steve. An external scoop not only increases parasite area but the hole itself gives additional cooling drag due to slowing down the air entering, hence a NACA duct is a prefered solution.

 

I've cut-out a piece of cardboard to shield the air filter from the radiator exit air, but I need to monitor the inlet temperature to see what difference, if any, it makes.

 

Mole, what did you use to monitor you air temperature - indoor/outdoor thermometer, or something more technical?

 

BRG Summertime Brooklands SV 😬 It is only with the heart that one can see rightly; what is essential is invisible to the eye. (Antoine de Saint-Exupery)

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An initial unscientific encouraging result from shielding the air filter fitted to the front of the airbox.

 

After the drive home last night the whole airbox was warm to the touch after shutdown.

 

Fitted a piece of cardboard that spans the gap between the top of the radiator and the underside of the air filter.

 

After the drive home tonight the airbox felt noticeably cooler to the touch - and the cardboard hadn't blown away *eek* If this works I'll rig-up a sheet of aluminium that will continue underneath the airbox to its rear end, so that warm radiator exit air can't affect the airbox or the filter.

 

Obviously I need to monitor the air inlet temperature, but haven't sourced a suitable means of doing so. I saw some cheap inside/outside thermometers on the WWW last night which might do the trick - what do other people use?

 

I also plan to monitor the Emerald inlet air temp readout, but need to make a suitable hole in the bulkhead through which to pass the plug.

 

As soon as I have some reading I'll post them 😬

 

Always seeking the EASY solution 😬

 

BRG Summertime Brooklands SV 😬 It is only with the heart that one can see rightly; what is essential is invisible to the eye. (Antoine de Saint-Exupery)

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I used a small digital display from Maplin that allows up to four remote temp sensors to be connected (it also doubles as a clock!). I've put one temp probe right at the front of the chassis, shielded as much as possible from the cooling effect of high speed, and one in the airbox via a grommet in an unused hole in the backplate. The display unit is rigged with a small switch so I can switch the display between the two sensors and see the relative readings for external and inlet temperature. Cost of the whole set up - an amazing £16 plus battery, cable ties and a piece of ali to mount the display (p 645 of last years Maplin Catalogue part nos FE33L and 2x FE34M). I can send photos etc if you let me have an e-mail address.

 

 

Edited by - Mole on 19 Mar 2004 23:16:22

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Hmmmm, makes me wonder: I am running 45 Webers with the usual K&N filter setup sticking halfway through the bonnet. That would mean the first two cylinders get the warm air from the radiator and the rear ones the fresh air from outside. That does not sound good for balancing, but I suppose the difference is minimal??? On the other hand, maybe a little shield would help.

 

Gert

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Just using the Emerald ECU air temp readout the crude cardboard air filter shield gives a slight improvement 😬

 

Without crude shield: OAT 6 deg C, inlet temp 20 deg C = 14 deg C rise

 

With crude shield: OAT 13 deg C, inlet temp 23 deg C = 10 deg C rise ( 4 C deg better)

 

I've got one of the Mole recommended gadgets on order from Maplin, but it's currently on back-order. It's switchable facility from several locations will make the readings more accurate and meaningful - Thanks Mole 😬

 

I'll keep you posted.

 

BRG Summertime Brooklands SV 😬 It is only with the heart that one can see rightly; what is essential is invisible to the eye. (Antoine de Saint-Exupery)

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I've just spent the evening with cardboard, scissors and sticky tape making a box round the air filter so that it's shielded from the radiator and takes most of its supply from the air flowing past the radiator and down the side of the nosecone. Hopefully road testing over the weekend - watch this space for results .... *smile*

 

Edited by - Mole on 19 Mar 2004 23:03:55

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