Top speed test/different hoods!

[Guest]

Hello again!

I wonder if there is anyone who has experienced the GTD-40 Mk1 car in very high top speed tests (about 300km/h at public road or simular?) - and if there´s any problems with liftforces! There is different hoods - does it matter which one you use? - any comments around this topic!

Some of the original Lemans 40´s was also fitted with shelter in the front...! Is it possible to buy these things...?

Klout

 

[Paul Thompson 'Hooligan']

Hello
Roy Smarts MK1 GTD has been to 276KPH without any unpredicatable handling detected. The most noticable thing was how long it takes to slow down! The runs were on road tyres at an aerodrome and the car was not affected to any great extent by crosswinds either.

regards
Paul Thompson

 

[Guest]

Hi Paul!

Thank you for your quick answer - I´m wondering if I have to buy a new hood - I have the one with two vent. openings...! Wondering if someone know if there is a big difference in downforce in front with the other hood?

It would be nice showing some friends that our GT40´s also can match their newer cars in top speed range! I´ve already proved the handling capacity and the great acceleration last summer.....for some porsche friends heheh!


Thank you!

 

[OMeyer]

Klout - It is my understanding that the MKII hood with the single outlet was an improvement as far as downforce. Maybe someone else can expand on this.

 

[Jim Glickenhaus]

The single outlet is less restrictive hence more cooling. The air dams on the MK-IV futher refined this by keeping the slower flo from this outlet from mixing with the faster flo over the body and creating drag and reducing downforce.

 

[Brian Magee]

Hi all
It depends on who's hood you have and how it is constructed in front of the radiator. Standard GTD hoods (nose panels to us Brits) started halfway up the radiator and so half the air would go below and into the front area. As on a GTD this area is fairly well sealed it would have the effect of trying to lift the hood off. Make sure, whichever type of hood you use that all of the air exiting the radiator goes out of the openings.

Brian.

 

[Julian West]

As Brian mentioned the stock GTD nostril panels tend to 'bulge' due to the poor design. They also allow hot air to be forced against the footwell, which increases cabin temperature.

 

Hi there!

(I´m former klout but had to reregister because of technical error!)

Today I`m using a Mk1 hood - with two openings in each direction! I have noticed the effect of the "bulk" already and it´s therefore I would like to use another hood! I also think that the other hood will make better downforce in higher speed! - please leave comments at this topic if you have experinenced some difference!!

If I would like to buy a new front hood - Is there any specific brand/mark that supply a front hood that stands for very good quality design and that also fits my GTD?

Thank you

Christoffer/Klout

 

[Brian]

Guys, If you like the looks of the twin opening panel, but not it's air handling capabilities, talk to the guys in the GTD Club. Some have done modifications which retain the looks, but move air as if it were the large single opening. I have some pics, but can't get them on line. I think Frank Catt does the modification in his shop for those that wish.Brian

[ April 06, 2002: Message edited by: Brian ]

 

[MWGT40]

Yes Frank Catt of Wealdon Engineering provides this modification. I am currently having it carried out to my GTD which is with Frank now.

 

[Guest]

Brian,

If you send me the jpegs, I'll post them to this thread.

Thanks,

 

Thank you for all great answers!

I would love to see pictures over Fred´s modifications with the hood!

Thank you for helping me in this matter!

Christoffer

 

[Guest]

Folks,

Here is a JPG from Brian showing the modified GTD two nostril hood.

Thanks Brian!!!

Comments?

[ April 07, 2002: Message edited by: mike_starling ]

 

[Robert Logan]

Klout,

The MkII used a single nose with a splitter to try and maintain some form of transient flow. The splitter was made in aluminium and can be clearly seen on most photographs of 1046 (1966 winner) the black and silver MkII.

At Roaring Forties we offer both the single and double nostrals but because of the A/C fresh air intake tube we used the MkIII as the basis. This has a slightly larger gap on the outsides of the openings.

The single gives better stability and better cooling I feel but the double is how the GT40's should look.

The coments about over heating are due to the side seals used on the front clip of the GTD cars and others. These are positioned slightly outside the central nostral and as I remember on the GTD are fibre glass and have a rubber seal on top of them which seals to the underside of the front clip. This restricts the air's exit to the holes around the filler caps and the gap infront of the front screen. We guide the hot air from the radiator that does not escape through the nostral into the wheel arch areas and are even considering using this air to COOL the brakes.

Hope this helps,

Best wishes,

Robert

 

[Jim Glickenhaus]

Robert
Two of the LeMans MK-IV's were prepared by Holman and Two by Shelby. The Holman cars had oval vents next to the radiator inlet on the nose that led to the front brakes. At LeMans the cars braked from 223 to 25 at the end of the 3 mile mulseanne strait. The thermal shock caused by over cooling on the strait caused rotors to warp and along with a reversed pad during a pit stop sent Andretti into the wall. The Shelby MK-IV's blanked off the nose ducts and took warmed air from behind the radiator and ducted it to the front brakes. One of these cars finished first and the other finished fourth. On the street I find Shelby's solution works very well.

 

[MWGT40]

Christoffer

The picture shown is of the modified twin nostril which gives a similar effect to the single nostril seen on the MK II cars and the later MK I GT40s, particularly those run by the Wyer team with Gulf in 68 and 69.

However, most of the GT40 MK Is were fitted with the twin nostrils - so the modified twin nostril lets you have your cake and eat it i.e. looks right but gives the cooling characteristics of the single nostril.

Contact Frank Catt if you want more details.

 

Mike/Brian!

Is the hood at the picture a modified single or is it based on the "twin"?

Is it a big difference in handling capacity/stability between the different hoods? Particulary in the highspeed region?

Is there anyone that has experienced both hoods and that can tell me the difference?

Thanks

Christoffer

 

I did some top speed testing with my prototype. According to a GPS installed in the car I hit 171.5 MPH with a spilt hood. The front end was a little light but still very controllable.

 

Okay... Stop teasing. Give us some real info.

Doug