The BORA | Page 39 | FerrariChat

The BORA

Discussion in 'Maserati' started by wbaeumer, Aug 11, 2011.

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  1. staatsof

    staatsof Nine Time F1 World Champ
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    Mar 13, 2005
    91,367
    Fuggetaboutitland
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    Bob
    So you've increased the size of the center opening and then stuck a fan in it. But have you tried running the car with just the new bigger opening and no fan in place?
     
  2. ralt72

    ralt72 Rookie

    Dec 4, 2020
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    James Nelson
    You can see the vents, at mid-way down the picture. What are the fan's dimensions ? Did you notice a drop in engine running temperature ?
     
  3. Froggie

    Froggie Formula Junior

    Sep 27, 2017
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    Belgium
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    Serge
  4. am117au

    am117au Karting

    Apr 22, 2014
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    Sydney Australia
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    Greg G
    Bob.
    The opening had no mods done to it unless a previous owner did, however i doubt it has been modified. I did make some changes to the pipework when i had them manufactured in SS.
    After i upgraded the alternator and installed the SPAL-EF3632 FAN 12in i had an great improvement without the 3rd fan but i felt it was running without any spare capacity especially on a hot day with over 30deg ambient temperature. However by installing the 3rd fan it helps draw out a larger capacity of hot air from the compartment in front of the trunk and incredibly it also pushed the expelled air lower to the ground thereby pushing it away from the car which helped to reduce the cabin temperature.
     
  5. am117au

    am117au Karting

    Apr 22, 2014
    222
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    Greg G
    Serge,
    My car is an early European car and does not have the vents mid way down the front.
    The fan size from memory is 71/4 " I tried to fit an 8"however it was too large.
    I can say without the main fans been ungraded and the 3rd fan installed the car couldn't handle ambient temperatures above 25deg without over heating.
    Whether this will improve as the rebuilt motor further runs in only time will tell.
     
    Froggie likes this.
  6. staatsof

    staatsof Nine Time F1 World Champ
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    At high rates of speed the fans don't really do all that much especially if the air flow has been properly designed, quite dubious in the case of the Bora. In fact they can cause blockage which is why on some cars utilizing a puller setup you see a cowling to enhance the pulling effect across the entire radiator surface but you'll also see blow through rubber flaps on the shroud so that there's less obstruction once the car is going quite fast. But in around town driving on warm days I can see how this might be quite an effective booster and get the hot air out from under your car. On the Bora's with hood (bonnet) vents that hot air is dispelled upwards instead. I met Ing. Alfieri once in Monterey and sat with him at dinner along with Tom Tjarda and their wives. But that wasn't the place for technical discussions. However we did did have some good discussions on the concours field along with my friend, a fellow Bora owner, who acted as a translator. There were so many things to discuss and I wish I had thought of asking about the transition to the vents in the hood. But this was his first and beleive his only visit to that show and was quite taken aback to see all of the old cars he had helped to design and get manufactured in such good condition and reverence. It really moved him.

    I've done a lot of high speed driving for long periods of time on hot days as we have the room to do so in Nevada and other states. I tried an adjustable in angle extraction scoop mounted on the leading edge of those vents and spent half a day fiddling with it out in the desert and high speed but I didn't notice any improvement in water temperatures. So I've always been suspicious about the basic design of the airflow path of the late cars. It hits that vertical wall of the extra cowling and then has to make a 90 degree escape out the top which is why I tried the extraction scoop. It really needs some time in a wind tunnel ... as if!

    I'm also of the opinion that the airflow in the engine compartment is the actual Achilles heel when if comes to heat issues. It simply collects in all that steel mass and WO adequate airflow though there it puts an additional impossible load on the cooling system. We thought about small fans mounted on the underside of those two horizontal air exit openings on rear deck of the hatch but never tried that. That's a pretty big visual departure from originality as well. All the Bora owners over here who drove there's at the track in the summers or even long trips have experienced heat soak in the engine compartment and could be seen parked in the shade with the hatch up and cover removed. When it was bad that's about a 45 minute cool down stop. Picnic or lunch time!

    My favorite idea for a modification is to cutout the back of the hatch's vertical area and replace it with the kind of mesh or slat work you saw on some mid engine Ferraris and other cars from later years.

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    Those cars also have cool air intakes just before the engine compartment. That would be a big help as well. But these are tremendous changes in appearance to the car and I wasn't going to do that.
    My car never boils over but it does get too GD hot.

    My friends aforementioned Black Bora, a 73, didn't get as hot but he had early issues with cavitation and it would spit coolant at times which he solved with a new water pump impeller design.
    But he also didn't go on long high speed runs in hot weather.

    Keep us posted on your interesting modification.
     
    christof schlicht likes this.
  7. boralogist

    boralogist Formula Junior

    Jun 21, 2005
    998
    Mine is an identical Euro 1972 also.
    As I wrote above I think you have come up w/a brilliant idea which, w/your permission, I would like to copy;)
    Would it be possible to share the exact make/model of the fan you used.

    Thanks.
     
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  8. 71Satisfaction

    71Satisfaction Formula 3

    Jul 15, 2012
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    Art
    If you can keep a Bora from overheating with the engine running and the car at a stand-still in 30+C ambient air temperature - you have done well. That must be the most hateful condition in which to have to operate any car..

    I still find it personally frustrating that a more passive solution hasn't worked on your Bora, Greg, because I started with my Bora overheating within 5-10 miles of driving it, and just kept at it until we found the problems. That worked for mine, and I wished it for yours as well. However, at this point, I yield and conclude that the difference mine must benefit from is its top-vented hood.

    I don't know if anyone else recalls this experience I shared a couple years ago - but it is worth repeating...

    Driving home from an August car-themed fundraiser, I fell in with a loose group of Ferrari, Lamborghini, and McClarens heading towards the highway. Ambient was 90F-ish. I always keep half-an-eye on gauges, and water temp was in the 90+C range. Once we hit highway cruising speeds of 80-90mph I expected the temperature to drop, but it persisted around 90C, indicating to me a load-vs-heat-saturation that was going to take a while to dissipate. The others got a little excited and before you know it were up around 120. Against better judgement, I decided to catch up and see what the Bora could handle. I visited 140 while catching up to them...

    ...one glance at the temperature gauge and my concerns vanished. It had not taken more than a few minutes at those much higher speeds, for the Bora to cool to its nominal 75C..!

    And it struck me - of course- how brilliant. That's exactly when Alfieri et al would *want* its cooling system to be most effective. And those speeds were probably the norm for many more Bora owners in the '70's than these days.

    Lesson learned.

    Cheers,
    - Art
     
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  9. ralt72

    ralt72 Rookie

    Dec 4, 2020
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    James Nelson
    I think running a small Gurney lip on those vents would help on the highway, not so much around town.
     
  10. am117au

    am117au Karting

    Apr 22, 2014
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    Greg G
    Yes. I installed gurney lips on both the openings how effective this has been i haven't been able to measure.The persistent problem i had was in city traffic rather than on an open stretch of road.
    Greg
     
  11. am117au

    am117au Karting

    Apr 22, 2014
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    Greg G
    Boralogist
    I double checked to provide you with the correct information. I used was an 8" Maradyne.
    The logic for me was it was the shallowest available and had a low consumption draw of 8.1 amps. However a Spal could be more effective but has a higher draw.
    Regards
    Greg
     
  12. staatsof

    staatsof Nine Time F1 World Champ
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    Have you also upgraded the radiator? I know that some GT car owners put in a radiator fan override switch to turn on the fans early before entering congested traffic. A well designed cooling system shouldn't need that. If your modification has worked for how you use the car then great! Maserati didn't add those vents on top as a styling exercise. That's how they tried to solve a problem and it didn't quite work under all conditions. Here in the USA that was on the 1975 and after models so maybe this was initiated by DeTomaso? Another interesting question, who initiated this change?
     
  13. am117au

    am117au Karting

    Apr 22, 2014
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    Greg G
    Bob.
    The slats or some adequate venting i believe would have alleviated some of the problems we are currently experiencing but as you hinted that is taking it a little to far from the original design.
    I have also pondered how Maserati used the same radiator size for the Bora and Merak together with an oil cooler for their v6 .
    I have noticed the water temperature rise always follows the oil temperature and had they installed an oil cooler at the front of the car we probably would be having this conversation.
    Regards
    greg
     
  14. am117au

    am117au Karting

    Apr 22, 2014
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    Greg G
    Bob.
    I did upgrade to a 3 core copper radiator. I probably should have gone aluminium as 2 of my friend did on their Khamsins which completely cured their overheating problem.
     
  15. boralogist

    boralogist Formula Junior

    Jun 21, 2005
    998
    Thanks Greg. Really appreciate your help.
    BTW---I did install a Setrab oil cooler up front.
    Huge difference. Highly recommend it!
     
  16. staatsof

    staatsof Nine Time F1 World Champ
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    My upgrade was to a 2" core with 14 fins to the inch. In retrospect we beleive that was too high a fin density. I never went back and tried 12 fins per inch. Some guys I knew did and seemed happy with that.
    They weren't trying to use the Bora in the extreme manner that I was though. I don't remember whether those were top vented cars or not? Those former owners are all gone now.

    I don't think the vents are bad looking, certainly not like the huge and ugly rear rubber bumper was.
     
  17. staatsof

    staatsof Nine Time F1 World Champ
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    The Merak also has a completely different engine compartment design, far more sensible for shedding heat.
     
  18. am117au

    am117au Karting

    Apr 22, 2014
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    Greg G
    That says it all.... what chance have we with the Bora but gee i love it.. I took it out for a long drive today and it performed spectacularly.
     
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  19. staatsof

    staatsof Nine Time F1 World Champ
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    If it's working well now for you and the way you drive then just enjoy it. They are amazing cars and I can only wish that the factory had assembled and finished these cars the way you have but then they went broke back as it was finishing the cars the way they did. The last cars didn't get painted body color under the hatch and the body work on those two compartments on each side and the adjoining area was quite crude by comparison with the early cars. Mine had no paint at all in some parts of the engine compartment ... just undercoating! I remedied that.
     
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  20. boralogist

    boralogist Formula Junior

    Jun 21, 2005
    998
    PS
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  21. italiancars

    italiancars F1 Rookie

    Apr 18, 2004
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    [QUOTE="staatsof, post: 147897949, member: 17261]. Here in the USA that was on the 1975 and after models so maybe this was initiated by DeTomaso? Another interesting question, who initiated this change?[/QUOTE]

    If you look at Panteras built after 1974, they too have similar vents in the hood.
     
  22. staatsof

    staatsof Nine Time F1 World Champ
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    Probably just a coincidence that both were being run by the same guy ... ;)
     
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  23. boralogist

    boralogist Formula Junior

    Jun 21, 2005
    998
    Hey---

    Anybody familiar w/a US 1973:
    AM117.49.500

    Thanks.
     
  24. boralogist

    boralogist Formula Junior

    Jun 21, 2005
    998
    #974 boralogist, May 20, 2021
    Last edited: May 20, 2021
    Hi Greg---

    Just curious---
    Did you install an oil cooler during/since your amazing restoration?
    If so, same format as mine above or a different location?

    Thanks.
     
  25. am117au

    am117au Karting

    Apr 22, 2014
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    Greg G
    Boralogist.
    Unfortunately i haven't installed an oil cooler as to do so would have meant modifying the front in some way to be able to feed cool air through it. My car doesn't have the 2 lower openings.
    And unfortunately there is no fresh air available at the back of the car to install a cooler although i look at this seriously.
    Should i ever want or need to take the cooling to a higher level my next step would be to have a higher efficiency radiator fabricated most probably in aluminium.
    I have had some in depth conversations with a local radiator manufacturer here in Australia and he assures me he can test my radiator and advise if he can make a radiator with a higher efficency. before doing so. Right now i am going to enjoy the car as it is.
    Greg
     

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