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[quote=nota;887098]:)
Its the 'radial head' Repco-Brabham V8 engine featuring the Type 750 4-valve cylinder heads, circa 1968
4 camshafts / 4 intake manifolds / 4 exhaust mainfolds
32 diagonal tangentially ported inlet and exhaust valves resulting in 16 inlet trumpets and 16 exhaust pipes
:eek:
It was an un-raced F1 test engine (one-of-one) and btw its likely those images have only recently been made public, via another forum[/quote]
I'm confused, and impressed. :eek:
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FOudn it. interesting.
BTW other forum had it in 2007 :) [url=http://forums.autosport.com/index.php?showtopic=65534&st=80]Repco Brabham V8 engines - The AUTOSPORT Bulletin Board[/url]
fpv, what do you mean by "other way round" ?
This setup would be necvessary for a very fast 7 ... they do tend to get light at the front :(
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The 2 elements appear to be set at different angles, with the upper element at a lower AoA than the bottom element. I wouldve thought having the upper element at a higher angle to the lower one wouldve worked better.
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ah got you ... I woudl suspect the upper element prevents complete breakaway of air from the lower element ensuring enough air gets into the radiator.
The lower one will ensure very little air gets under the car :)
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[quote=Matra et Alpine;887116]
BTW other forum had it in 2007 :) [/quote]
Point being? :)
2007 = 20 months ago, regarding an engine built 41 years ago, hence qualifies as "recently" to me
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Got it in one Matra, but it still gets a bit light, at PI last year the clubbie was geared for 277kph down the straight. The aero still needs work the rear wing seems to work but the front does get a bit light:eek:.
Matra the engine is a sr20det with forged cp pistons and 34psi of boost. Its head has been cleaned up, shotpeeneed rods and conrods, arp bolts in the bottom end head. Stock sr plenum running with a modded throttle body, 800cc sard injectors, custom made exhuast manifold, its rev limited to 7200rpm. Its a very basic bit of kit but the power to weight and mechanical grip certainly help it.
The guy that races it has never raced before and to be honest its far too much car for him, he should of started with a normal clubbie wih 200 hp and gone from there. On the weekend he buzzed the engine to 9200rpm on a missed downshift,
I should get you some pics of Craigs hotrod, instead of going the normal chev BB route he has a 6.2l Merc v12 that has been tuned for 620bhp :cool:
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^^^^^^ Well you have to ignore the first 20 years of that as no forums online picture galleries etc etc
Not sure what that has to do with "recent" as "recent" has nothing to do with the duration of things
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[quote=Matra et Alpine;887140]^^^^^^ Well you have to ignore the first 20 years of that as no forums online picture galleries etc etc
[/quote]
In your world does the term "made public" not extend to forms of media other than the internet?
[quote]
Not sure what that has to do with "recent" as "recent" has nothing to do with the duration of things[/quote]
Again thats bullshit, it has [i]everything[/i] to do with the duration in-between the past and the present.
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[url=http://www.dictionary.com]Dictionary.com[/url] can be your friend :)
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^ more my friend than yours
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I always found radial valve heads interesting.
BTW here is a modern interpretation:
[URL="http://www.fastdates.com/PLN.NewBikes/BMW/HP2/HP2Sport.Valves1008.jpg"]here[/URL]
Its the BMW HP2 Sport engine that has radial valve heads. It's not quite the same as the engine you showed nota because the intake valves are both to the front (i.e. the intake valves are not placed diagonally from each other). But it is still a cool idea. Definitely usefull for a high reving, short stroke engine.
I think current F1 rules don't allow radial valve heads IIRC?
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AS a single cylinder setup it's really a "no difference" for the BMW, it can chose to take air from all sides no problems.
Tyring to do that in a multicylinder block makes the ehad too complex and little benefit,
Minor correction too, the Beemer boxer engine in HP2 new head, lightweight pistons "high revving" option is 9,500 .... that's tickover for most bikes :) Sadly it also has a long stroke of 73mm, compared with for example the Honda Blackbird's 58mm.
So not sure what comparions data you're using to assume revving and stroke "benefits" ... other than BMW sales literature which definately says ity is "high revving" :) :)
F1 has NO rules preventing use of radial valve combuisiton chamber shape.
EXCEPT, you'd struggle to get the levels of compression to compete and the space required to site and operate radial valves is limited. Mind you with all the engine changes in the last few years, I woudlnt' put it past for at some point somebody wanting to control combustion chamber shape :)
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[quote=Matra et Alpine;887216]AS a single cylinder setup it's really a "no difference" for the BMW, it can chose to take air from all sides no problems.
Tyring to do that in a multicylinder block makes the ehad too complex and little benefit[/quote] Actually the BMW has a pretty normal intake and exhaust setup. Only one intake trumpet per cylinder and a single exhaust pipe per cylinder aswell. As I noted it isn't the same as the racing engine shown but it is still a radial valve design.
[quote=Matra]Minor correction too, the Beemer boxer engine in HP2 new head, lightweight pistons "high revving" option is 9,500 .... that's tickover for most bikes :) Sadly it also has a long stroke of 73mm, compared with for example the Honda Blackbird's 58mm.
So not sure what comparions data you're using to assume revving and stroke "benefits" ... other than BMW sales literature which definately says ity is "high revving" :) :)[/quote] You do realise that it is a 1170cc flat twin with a 73mm stroke right? 9500RPM redline is pretty good for that engine. Do you know of other production engines that have a 73mm stroke that can rev higher?
Did you notice that it has a bore of 101mm? Thats bigger than alot of cars! Also the intake valves are 39mm dia. and the exhaust valves are 33mm dia, that is pretty big for a 101mm bore engine.
[quote=Matra]F1 has NO rules preventing use of radial valve combuisiton chamber shape.
EXCEPT, you'd struggle to get the levels of compression to compete and the space required to site and operate radial valves is limited. Mind you with all the engine changes in the last few years, I woudlnt' put it past for at some point somebody wanting to control combustion chamber shape :)[/quote]
Interesting that there is no rule against it... I thought there was a rule stating that valve sets had to be parallel...?
Technically there is a rule against it right now as the engine design is frozen AFAIK.
You do realise that the HP2 is running a 12.5:1 compression ratio...? and did you notice how shallow the valve reliefs where in the piston?
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ht, not only do I know about the BMW engine, but mate has a classic and we've stripped a rebuilt it often :)
So, yes WELL aware of the revs, dimensions and issues.
BUT like before YOU did not qualifty so the responses were NO it does NOT have "high revs" and NO it is NOT "short stroke". Can't get away with NOT bringing all the facts in if then used later as justification :)
And as for claiming techincally no rule as the engine is frozen then that's just weak .. SO WEAK :) :)
Let me repeat, the reason is radial valves are a nightmare for valve opening, the camshaft to valve now has to go through angular translation as will as linear ... very VERY bad.
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[quote=Matra et Alpine;887277]BUT like before YOU did not qualifty so the responses were NO it does NOT have "high revs" and NO it is NOT "short stroke". Can't get away with NOT bringing all the facts in if then used later as justification :)[/quote]Does an engine only qualify as high revving if its redline is over some arbitrarily chosen number? What do you consider "high revving" what RPM must an engine be capable of to earn that in your mind? As far as I'm concerned 9500RPM with a 73mm stroke is high revving. There is the same problem with stroke... What arbitrarily chosen value must an engine have to be considered "short" stroke in your mind??? As far as I'm concerned I consider bore:stroke ratio and in that case the HP2 Sport's engine is more than short stroke.
[quote=Matra]And as for claiming techincally no rule as the engine is frozen then that's just weak .. SO WEAK :) :)[/quote]How is that weak? I thought I was stating the obvious point that since engine design is frozen then they can't make an engine with radial valves... As it stands any discussion about the possibility of F1 using a radial valve head is pure conjecture.
[quote=Matra]Let me repeat, the reason is radial valves are a nightmare for valve opening, the camshaft to valve now has to go through angular translation as will as linear ... very VERY bad.[/quote]Ummm BMW seemed to have a nice solution with conical cams and cam followers that are mounted at the same angle as the valves... the resulting forces are exactly the same as a normal valvetrain... BTW this is the first time you have mentioned this problem, last time you mentioned that it might be hard to achieve a high compression ratio and that the space for the radial valves was limited...