Nostrils?

[Rich A]

What is the benefits of the Single and Twin Nostril hoods.

[Bill D]

The twin vent nostril was used first. They found that air didn't exit fast enough. This caused front end lift. The single vent nostril was used later and it allowed more air to exit.

[Mark Charlton]

Originally Posted by Bill D

The twin vent nostril was used first. They found that air didn't exit fast enough. This caused front end lift. The single vent nostril was used later and it allowed more air to exit.

...which is why some with twins have enlarged them (deeper) for better air-flow while keeping the appearance.

[40 Bud]

I thought I read that the twin nostril was used at the slower tracks and the single was used at the longer high speed tracks.

[Ian Anderson]

I had heard that at Le mans they needed to take the spare tyre out of it's holding area and touch it on the ground and replace it in the car at the pit stops.

They could then replace with tyres from insie the pit. (along the lines that the drivr could change the tyre with one he was carrying in the car.

In order to get the spare tyre under the nostril they changed the design to 2 nostril as the tyre took up the same space as the center of the single nostril.

Rules changed and hence the nostril changed as the single allowed better air flow

Now I din't know if this is correct but ertainly bade sense to me

Ian

[allanfeldman]

The twin nostrils were the 1964/5 first design P1006 design. I am certain that I heared in the past that the MKIII's nostril spacing or depth was different to a MKI. So those with KVA MK1 bodywork beware. Because all Ken Attwells moulds were taken from a MKIII.
In fact the 1966 MKIIa's had a single vent divided by a thin metal plate on the Shelby and Alan Mann's cars. Holman and Moody MKIIa cars not having this dividing plate.
As I understood it the single vent was tried on the M1 Mirage in 1967 prior to Le Mans. The Mirage used the single vent in its Spa victory and subsequently including Le Mans. The single vent was also used on the MKIIb's. The spare wheel was at the back seating upright on the MKIIb's so the wheel change in Ian's comments would not be necessary in the case of the MKIIb's.
Which brings us back to the MK1 the 1966 Le Mans there were 5 MK1 GT40's entered all having twin nostrils P1017 Comstock, P1040 Filipinetti, P1007 Ford France, P1038 Essex Wire and P1001 Essex Wire.
For the 1967 Le Mans race 3 MK1 GT40's took part twin nostrils P1020 Ford France,
Single vent P1042 Filipinetti, P1026 JWAE.
By the 1968 Le Mans all MK1 GT40 P1074, P1075, P1076 all JWAE cars P1078 Strathaven Ltd, P1079 C Dubois all had single vents.
In the 1969 Le Mans 7 GT40 MK1's P1075, P1076 both JWA, P1081 D.A.Z, P1009 M Guthrie/Alan Mann, P1033 E.S.C.A., P1082 Ford France all had single vents and the only GT40 Mk1 with twin nostrils was P1010 E.P.Sadler.
Since Ian comments apply to Le Mans I cannot ascertain to why single or twin vents would affect the extraction of the spare wheel especially as the GT40 production chassis took this into account. It had a half circular wheel well already incorporated in the production chassis run. Indeed the only car that had a bulge made to accommodate the spare wheel in a different position in it's front hatch that comes to mind was AMR/2 Paul Hawkins famous lightweight and that was a modified single vent.
Regards Allan

[allanfeldman]

Originally Posted by allanfeldman

For the 1967 Le Mans race 3 MK1 GT40's took part twin nostrils P1020 Ford France,
Single vent P1042 Filipinetti, P1026 JWAE.

Got it wrong should read

Originally Posted by allanfeldman

For the 1967 Le Mans race 3 MK1 GT40's took part all had
single vents P1042 Filipinetti, P1026 JWAE, P1020 Ford France, .

Number 16 1967 Le Mans P1020 Ford France had single vent sorry for wrong information previously.

Another fact this car had a widened rear clip at the Le mans trials and the 24hrs race of course. This was the prototype clip that became the Gulf cars rear clip the following year .
Regards Allan

[MikeP]

The twin nostrils don't flow air out as easy as the big single vent. however they can be improved by altering the shape underneath (see pic). They can be obtained from Frank Catt at Wealden engineering I think.
Mike

[Bill Musarra]

If you have the twin nostrils, any good fiberglass shop should be able to fix you up. I was lucky in that I had a guy who has worked on some of the originals and does work for several national race teams.

Bill

[Big-Foot]

Looks really nice Bill - I particularly like how the stripes were done!

[Brian]

Nice work!

[Bill Musarra]

thanks guys. I have always thought the stripes should be completed instead of being leftout of the nostrils. Sort of gives it that finished look I think.

Bill