Melling SP6 upgrade
Discussion
RE: Plans for Melling re-engineered Sp6 engine. Not wanting to be controversial, but........
Only 117 bhp/litre? I personally can't understand where this brick wall has sprung up from regarding engine performance limits.
How about 130bhp/litre from a normally-aspirated 40-year-old ford lump? Got you head scratching? read on..
In 1970 Cosworth designed the GAA motorsport engine. Based around a V6 'Essex' iron cylinder block with 3412cc, twin ohc/24 valve
It had a 100mm Bore with 72.14mm stroke. Over-square? You bet!
440bhp at 8-thousand-something rpm. Recent developments have pushed this figure to almost 500hp, (145 bhp/L) also, raised torque at low rpm thanks to better fuel management and made the engine even more reliable thanks to quality off-the-shelf components.
And not a Lysholm screw or centrifugal turbine in sight!
Ford had these engines in anything that moved on a track, competing against Chevy V8s in Formula 5000, their relative compactness and lightness
making up for any deficiency in outright power. (sound familliar, TVR owners?)
Back to today's discussion.. Following the temptation to go all GM and replace the poor-old-SP6 because, lets face it boring-out the six-pot will make the pistons waaay too big and unable to rev up to the required engine speeds to make that kind of power...
Speed six 96mm bore 92mm stroke
Melling SP6 upgrade 4.7L 104mm bore 92mm stroke
(Assuming, for the moment that the Melling conversion will bore the engine rather than stroke it.)
considering the GM LS7 (104.8 mm bore, same as above but 101.6 mm stroke) redlines at 7K. Though this was "only 7000" because GM wanted to guarantee typical lifetime stats i.e., what, 150-200 km? Testing of the LS7 showed 8Krpm capability. This WITHOUT forged pistons & using "fragile" Ti rods....
Given the 8.4mm shorter stroke & use of "proper" forged internals one would expect from this engine upgrade, I'd bet my next meat pie that Melling or any decent tuner could make the jump without the loss of too much sleep.
Seriously though, the cossie GAA & LS7 are just two examples of great motor sport engines from the last hundred years. To think that todays performance from reliable, efficient, mass-produced IC engines found in an "average" sports car would put 60's F1 technology to shame just bolsters the fact that improvements in materials & manufacturing technologies are constantly pushing "what's possible" to new limits.
I think its very easy to criticise the likes of Melling for being optimistic with his claims and having a big-gob, always spouting blarney to the press or whatever gets the average goat angry. Really though, this country hates its entrepeneurs, I can see why they all go abroad...
I myself am in utter awe of the man. A lifetime at the cutting-edge of motorsport powerplant design is a massive achievement.
Seriously, just take a look at the engines he's designed, then you might wish to choose to judge claims of initial SP6 designs as a "piece-of-unreliable-crap" with some suspicion. (Seriously, breaking down
after 15 mins at tickover, really.. more like some sod putting bleach in the oil to cock up the acceptance trials at TVR. (SHOCK!! Why would they ever do such a thing?? discuss..)
Only 117 bhp/litre? I personally can't understand where this brick wall has sprung up from regarding engine performance limits.
How about 130bhp/litre from a normally-aspirated 40-year-old ford lump? Got you head scratching? read on..
In 1970 Cosworth designed the GAA motorsport engine. Based around a V6 'Essex' iron cylinder block with 3412cc, twin ohc/24 valve
It had a 100mm Bore with 72.14mm stroke. Over-square? You bet!
440bhp at 8-thousand-something rpm. Recent developments have pushed this figure to almost 500hp, (145 bhp/L) also, raised torque at low rpm thanks to better fuel management and made the engine even more reliable thanks to quality off-the-shelf components.
And not a Lysholm screw or centrifugal turbine in sight!
Ford had these engines in anything that moved on a track, competing against Chevy V8s in Formula 5000, their relative compactness and lightness
making up for any deficiency in outright power. (sound familliar, TVR owners?)
Back to today's discussion.. Following the temptation to go all GM and replace the poor-old-SP6 because, lets face it boring-out the six-pot will make the pistons waaay too big and unable to rev up to the required engine speeds to make that kind of power...
Speed six 96mm bore 92mm stroke
Melling SP6 upgrade 4.7L 104mm bore 92mm stroke
(Assuming, for the moment that the Melling conversion will bore the engine rather than stroke it.)
considering the GM LS7 (104.8 mm bore, same as above but 101.6 mm stroke) redlines at 7K. Though this was "only 7000" because GM wanted to guarantee typical lifetime stats i.e., what, 150-200 km? Testing of the LS7 showed 8Krpm capability. This WITHOUT forged pistons & using "fragile" Ti rods....
Given the 8.4mm shorter stroke & use of "proper" forged internals one would expect from this engine upgrade, I'd bet my next meat pie that Melling or any decent tuner could make the jump without the loss of too much sleep.
Seriously though, the cossie GAA & LS7 are just two examples of great motor sport engines from the last hundred years. To think that todays performance from reliable, efficient, mass-produced IC engines found in an "average" sports car would put 60's F1 technology to shame just bolsters the fact that improvements in materials & manufacturing technologies are constantly pushing "what's possible" to new limits.
I think its very easy to criticise the likes of Melling for being optimistic with his claims and having a big-gob, always spouting blarney to the press or whatever gets the average goat angry. Really though, this country hates its entrepeneurs, I can see why they all go abroad...
I myself am in utter awe of the man. A lifetime at the cutting-edge of motorsport powerplant design is a massive achievement.
Seriously, just take a look at the engines he's designed, then you might wish to choose to judge claims of initial SP6 designs as a "piece-of-unreliable-crap" with some suspicion. (Seriously, breaking down
after 15 mins at tickover, really.. more like some sod putting bleach in the oil to cock up the acceptance trials at TVR. (SHOCK!! Why would they ever do such a thing?? discuss..)
Speculation about the Melling conversion/upgrade will probably just stay that I'm afraid as the man has upped sticks, lock stock and barrel and moved to Portugal in search of the holy grail of sports car manufacturing locations, leaving behind the majority (if not all) of his staff.
I imagine that will be the last we hear of him, certainly in relation to TVR engines etc.
I imagine that will be the last we hear of him, certainly in relation to TVR engines etc.
Given that engineers are held in such low esteem in this country i'm not at all surprised that he's left for better & greener pastures. Good luck to him!
To be honest.. my post was to question the rather negative reaction that the original press release had gathered. My point remains, why does the idea of a 500-odd sp-6 engine seem so impossible when it is so clearly not?! Its the same attitude that turned our motorcycle/car/aero industries into what they are today. Actually, f**k it, let the rest of the world overtake us at anything that actually matters, at least we have Simon Cowell to export to the world, that's got to be worth a few quid....
To be honest.. my post was to question the rather negative reaction that the original press release had gathered. My point remains, why does the idea of a 500-odd sp-6 engine seem so impossible when it is so clearly not?! Its the same attitude that turned our motorcycle/car/aero industries into what they are today. Actually, f**k it, let the rest of the world overtake us at anything that actually matters, at least we have Simon Cowell to export to the world, that's got to be worth a few quid....
Ford & GM had & have slightly larger budgets to build & develop engines tvr did'nt most development work was done by the people who owned the cars.
The design was changed on engines a number of times no doubt to save money
& not developed. only tvr power ,racing green etc etc have continued to develop the engine and good on them for doing so as its a great engine.
The design was changed on engines a number of times no doubt to save money
& not developed. only tvr power ,racing green etc etc have continued to develop the engine and good on them for doing so as its a great engine.
piemachine said:
Given that engineers are held in such low esteem in this country i'm not at all surprised that he's left for better & greener pastures. Good luck to him!
To be honest.. my post was to question the rather negative reaction that the original press release had gathered. My point remains, why does the idea of a 500-odd sp-6 engine seem so impossible when it is so clearly not?! Its the same attitude that turned our motorcycle/car/aero industries into what they are today. Actually, f**k it, let the rest of the world overtake us at anything that actually matters, at least we have Simon Cowell to export to the world, that's got to be worth a few quid....
Things are never as straight forward as they seem with Mr Melling. A lot of what Al says is taken with a pinch of salt as he has/had a tendancy to talk big but never deliver. I'm sure he has done many things very successfully for other companies that he can't talk about but his own projects (in the main) have been spectacular failures for either not being delivered or failing financially.To be honest.. my post was to question the rather negative reaction that the original press release had gathered. My point remains, why does the idea of a 500-odd sp-6 engine seem so impossible when it is so clearly not?! Its the same attitude that turned our motorcycle/car/aero industries into what they are today. Actually, f**k it, let the rest of the world overtake us at anything that actually matters, at least we have Simon Cowell to export to the world, that's got to be worth a few quid....
When I interviewed him for Sprint he said that the design of the Speed6 (both his and TVRs) was not capable of exceeding the BHP figure he quoted for a number of reasons, he was quite specific on the actual possible figure, I'll have to dig my notes out to find the numbers.
2mad said:
Ford & GM had & have slightly larger budgets to build & develop engines tvr did'nt most development work was done by the people who owned the cars.
The design was changed on engines a number of times no doubt to save money
& not developed. only tvr power ,racing green etc etc have continued to develop the engine and good on them for doing so as its a great engine.
It's a while since I've seen anyone make so many errors in such a short post.The design was changed on engines a number of times no doubt to save money
& not developed. only tvr power ,racing green etc etc have continued to develop the engine and good on them for doing so as its a great engine.
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