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575 GTO

Discussion in '365 GT4 2+2/400/412' started by 246tasman, Jun 25, 2007.

  1. 246tasman

    246tasman Formula 3

    Jun 21, 2007
    1,430
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    Will Tomkins
    #51 246tasman, Sep 26, 2009
    Last edited: Sep 26, 2009
    Wayne has kindly put bits from various threads together and because of this it's not so easy to see what's what without reading the whole thing carefully, so just to clarify:

    This car has evolved from around 1986 when we started to build it, though it was only completed around 1998/9.

    Evo 1. 400GT Chassis with 365GT4 2+2 wishbones/solid bushes/hubs/brakes, 2.4m wheelbase, 250GTO type space frame, dry sump mildy tuned (400bhp) 365GT4 engine, 400GT 5 speed box. Kerb weight was around 1300kg. Unfiltered warm air to the carbs.

    Evo 2. Wilwood calipers & discs fitted, rear hubs lightened by removing the drum handbrake mechanism, (ineffective kart calipers fitted for handbrake), rear bottom wishbones lightened & stiffened. 33kg saved from unsprung weight! Still running 400 brake servo with hydraulic bias adjustment.

    Evo 3. Same chassis/body, 575 engine with standard internals + throttle bodies and good exhaust system (601bhp/471lb/ft), 550 6 speed transaxle. Kerb weight 1195kg (less driver), weight distribution 50/50 front/rear. Filtered cold air feed to the trumpets. Removed brake servo, substituted twin bias-adjustable master cylinders, 360 brembo handbrake calipers.

    Jobs to do include increasing the rear wheel width from 8" to 9", and fitting a full roll cage to increase central chassis stiffness.
     
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  3. 246tasman

    246tasman Formula 3

    Jun 21, 2007
    1,430
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    Will Tomkins
    #52 246tasman, Sep 26, 2009
    Last edited by a moderator: Sep 26, 2009
    I don't know the numbers off hand, as my interest in chassis/engine numbers tails off after about #6000....I'll dig them out when I get a chance.
     
  4. X11OUD

    X11OUD Formula Junior

    Mar 22, 2008
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    Neil
    246tasman, has someone been spiking your morning tea????

    What an incredible project, massive congratulations on the car!! :)
     
  5. sir-t

    sir-t Karting

    Sep 24, 2006
    174
    D/A/CH
    congrats! what a project!
     
  6. El Wayne

    El Wayne F1 World Champ
    Lifetime Rossa Owner

    Aug 1, 2002
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    L. Wayne Ausbrooks
    Moved again to model-specific forum per OP's request.
     
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  8. Arvin Grajau

    Arvin Grajau Five Time F1 World Champ

    Jun 7, 2006
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    Arvin Grajau
    what are you going to do with it?
     
  9. VisualHomage

    VisualHomage F1 Veteran

    Aug 30, 2006
    5,579
    SoCal
    Very impressive.

    Body looks well replicated/convincing; I've seen some poorly executed GTO attempts since I've been on here/seen some at shows. But this is done very well. Great choices all around, color, choice of keeping the car faithful looking to the real one, ie, the Borranis, proper lights everywhere, the roofline and rear quarters look well-dimensioned. I like how it's built up on actual Ferrari chassis and undercarriage/engine. So it's heart and soul is all Ferrari.
     
  10. Jon Hansen

    Jon Hansen Formula Junior
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    Feb 6, 2007
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    Grand Rapids, MI
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    The second bubble does not do it for me. The first one looks better, but still awkward. I suggest a third design, something closer to the first than the second.

    Awesome project, and extremely well done. Congratulations to all involved.....
     
  11. 246tasman

    246tasman Formula 3

    Jun 21, 2007
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    Will Tomkins
    I agree. I'll be trying to extend the first in a gentler slope rather than the blunt front it has now. Can't wait to get back and start proper testing.
     
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  13. 246tasman

    246tasman Formula 3

    Jun 21, 2007
    1,430
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    Will Tomkins
    Race it (wherever it's eligible) , maybe some track days, occasional blasts on the UK roads to scare my friends, and continental trips where I can use it without fear of imprisonment. Have just driven for UK to Belgrade in a dull car and could have really used it!
     
  14. Indy430

    Indy430 Karting

    Dec 5, 2007
    210
    Indianapolis
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    RJ
    Incredible car! What a cool project!
     
  15. 246tasman

    246tasman Formula 3

    Jun 21, 2007
    1,430
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    Will Tomkins
    #62 246tasman, Dec 16, 2009
    Last edited by a moderator: Sep 7, 2017
    The car has now been fitted with (lower profile) Michelin TB15 tyres on 7.5 & 9 inch Daytona wheels. We're re-spoking Borranis of the same size to use with these tyres later. The photos (in fading light) show the wheel arches being flared at the rear to accomodate them. The arch cleco'd in place before being cut in and welded will be clenched over the inner panel and so still has 1/2 inch extra metal on for this purpose.
    I always felt before that the rear arches weren't quite right because when we widened the body shape originally we did it by carrying the arch further up and also left it a bit too big around the tyre.
    The new arches improve this to my eye, and I also think the car looks better closer to the ground as the original 6 inch ground clearance is more than really neccessary.
    The grip level of the TB15s is phenomenal compared to the old XWXs and I may have to fit a better seat now!
    We've done about 1000 miles on the road now with no apparent problems and really need to get it on the circuit next.
    I'm entering it for the VSCC Pomeroy Trophy at Silverstone on 27th Feb and am not sure we'll get any track time before then, so that might have to serve as the first real test.
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  16. koisokok

    koisokok F1 Veteran
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    Dec 8, 2006
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    kerim
    she looks mean!! great job..
     
  17. Daytonafan

    Daytonafan F1 Rookie

    Oct 18, 2003
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    Matthew
    Probably a very suitable car in the spirit of the Pomeroy
     
  18. ArtS

    ArtS F1 Veteran
    Rossa Subscribed Owner

    Nov 11, 2003
    6,084
    Central NJ
    A quick word of caution: The grip of those tires may overstress the Borranis - proceed with a bit of caution.

    Otherwise, cool mods!

    Regards,

    Art S.
     
  19. 246tasman

    246tasman Formula 3

    Jun 21, 2007
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    Thanks Art

    I have recently taken over a UK company which makes and rebuilds wire wheels and actually specialises in the manufacture of alloy rim competition wire wheels for historic & vintage racing, so we have the experience & technology to deal with this.

    We will be using heavy gauge stainless butted spokes and checking them regularly. Interestingly two of the chrome spokes on the 9in Borranis I had bought prior to acquiring this company had sheared at the head in the hub showing symptoms of embrittlement.
    I have another pair of 8 x 15 which I bought new from Borrani for this car about 10 years ago on which I specified painted finish and unchromed spokes and was surprised to find later that the spokes were chromed underneath the paint! Needless to say these will be respoked before further use.

    Will

    Will
     
  20. 246tasman

    246tasman Formula 3

    Jun 21, 2007
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    #67 246tasman, Feb 26, 2010
    Last edited by a moderator: Sep 7, 2017
    First track test was a couple of days ago at Mallory Park in the wet. Here's a shot of the car covered in road (& track) dirt on the way back.

    Apart from a couple of teething problems it all seems pretty good. We're going to put a bit more negative camber on the front wheels then off to Silverstone for the Pomeroy Trophy tomorrow morning. I've got a very stiff handicap and have to do 7 more laps in 40 mins than for example the two 911RS's which will take some doing, but it should be fun trying...
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  21. bigodino

    bigodino F1 World Champ
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    Apr 29, 2004
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    Very cool picture. Is the stiff handicap due to the horsepower of the 575 engine? Don't they take the suspension etc into consideration? Just curious.
     
  22. 246tasman

    246tasman Formula 3

    Jun 21, 2007
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    #69 246tasman, Feb 26, 2010
    Last edited: Feb 26, 2010
    There are 2 elements to the handicap. One is the overall handicap based on a very abstruse formula taking into account engine capacity, year of the car or engine (1904 =1, 1914 =10, 1924 =20 etc), distance from the rearmost pedal to the centreline of the back axle and probably something else I've forgotten. This is then applied over a series of tests: time through a zigzag of 5 cones, time between a fixed point passed at a speed of your choice and full stop between two lines, standing start 250m & flying 250m, and finally a 40 minute thrash where you are penalised if you don't do the specified number of laps. This latter is the one you're referring to and I don't know the formula. Maybe it's just estimated at the discretion of the organisers. I'll find out tomorrow.

    My overall handicap is 636 (applied over all the tests) compared to a 1950 Frazer Nash TT Rep at 55, or a 1931 Alfa 1750GS Zagato at 64 for example. They both have to complete 22 & 23 laps respectively whilst I must do 38.

    Just some mad English/British stuff really....
     
  23. alberto

    alberto Formula 3
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    Aug 25, 2001
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    So how do they avoid sandbagging by the competitors (I hope you understand this term). Maybe you tried to hard and ended penalizing yourself(?)




     
  24. RP

    RP F1 World Champ

    Feb 9, 2005
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    Thank you for sharing. I would love to see the expression of the people that see this coming down the road. Yes, yes, not a "real "GTO, all that purist BS, but you having great fun driving it, more power to you, that is all that matters!!

    Wonderful!!
     
  25. GrayTA

    GrayTA F1 World Champ
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    Jun 25, 2006
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    Wow, looks very cool. I havent seen this before today.

    Nicely done!!


    PDG
     
  26. Napolis

    Napolis Three Time F1 World Champ
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    Oct 23, 2002
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    Jim Glickenhaus
    Looks Great with Road/Race Grit!
     
  27. 246tasman

    246tasman Formula 3

    Jun 21, 2007
    1,430
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    Glad you like it Jim!

    Actually I was inspired to convert it from it's original 365GT4 spec engine & transmission when I first read about your P4/5 and thought, hell, why stick with dinosaur era components and why not just build what you want...
     
  28. 365gt2+2

    365gt2+2 Karting

    Nov 28, 2006
    168
    with the wife
    Full Name:
    Norman B'stard
    Have seen this car.. never really paid it much attention.. just another GTO ..

    whats the latest?
     

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