RE: Chimaera LS6
Discussion
dinkel said:
vjj said:
making a mockery of TVR's torqueless 4.2 and 4.5 v8's
I thought I had it all for today when someone over here asked who Gordon Murray was . . . But surprise surprise . . .
Simple Q: why a Chevy and not a Ford - say - 4.7?
My experience of ford engines is they are primitive and corners have been cut. Or they are overly complex. I work with rovers, chevys and fords. The older fords I've seen are cursed with poor design features.
Boosted.
vjj said:
the unreliable monsters that surfaced from mr melling.
That'll be the same Al Melling who's designed a number of race engines for well known teams, one of them being a Suzuki bike unit that's won more championships than any other in history?
Are Melling's 4.5s and S6s unreliable? Who knows, they were altered from his design before they ever got near a TVR engine bay. So given the pedigree, which he and MCD do actually have, it's very likely a 'no'.
As for the LS-conversion Chim, I saw that at Snetterton, and it is a very tidy job. Most impressive.
>> Edited by MarkoTVR on Saturday 24th September 00:59
Ted said:
Power delivery is incredibly smooth and predictable and weight is a little down on the Rover unit. The engine is also placed a few inches further back than in the standard car.
The TVR's engine is so far back, making it a front mid-engined design, that I'm surprised that they were able to get the Chevy powerplant even further back. That said, I believe that it's a good thing they did since I'd find it hard to believe that the Chevy engine is lighter than the Rover. I'd like to see an LS1/LS6 on a scale along with a Rover V8 in the same state of dress. I don't want to guess their weights, but according to what I've read, the Rover should be significantly lighter.
Ted said:
So how does an American V8 affect the character of this most British of sports cars?
Yes, I suppose that this Rover V8 is completely unrelated to American pushrod V8's.
vjj said:
making a mockery of TVR's torqueless 4.2 and 4.5 v8's
Well, in comparison to the Chevy 5.7, the TVR 4.2 and 4.5 will fall short of torque. Besides, aren't those AJP8 engines in a high state of tune and not exactly tuned for low-end torque?
dinkel said:
Simple Q: why a Chevy and not a Ford - say - 4.7?
Pushrod engines have two advantages over OHC engines-especially in such an application-where it's clearly a tight fit and weight (along with weight distribution) is also a major concern. Those advantages are packaging and weight. Pushrod engines have lighter, lower, and simpler heads, making these engines significantly lighter and physically smaller than even a SOHC engine of similar displacement. They are also cheaper, to boot.
So why not go with a Ford engine? It's a matter of philosophy-Ford's versus Chevy's. In the 1990's. Ford decided to completely give up on the pushrod V8, replacing it with a series of SOHC (2 and 3 valves) and DOHC (4 valves) 4.6 and 5.4 liter V8 engines. You have more expensive, smaller displacement engines that produce less power in stock form and are more expensive than a comparable Chevy.
Chevy, OTOH, decided that the pushrod engine still was a good idea, and they designed one for the 21st century, keeping only things such as bore spacings and other basic block dimensions the same. It was a clean sheet design with many, many improvements.
Being an OHV engine, for a given size and weight, it could have plenty of displacement, which would give it great torque throughout the rev range and still produce plenty of power. These engines can also be bought new for a very good price.
Going with a Ford 4.7 (289) or 4.9 (302) gets you an engine that is basically, at best, a somewhat updated, fuel-injected version of a forty year old engine, much like the L98 Chevy's-the last Gen 1 Chevys and TVR's Rover/Buick (sorry, couldn't resist) V8's.
Miguel
A very nice conversion, well planned and executed. The LS6 is a nice engine with plenty of power and completely different in character to the Rover.
Having said this please don't start slagging off the Rover V8 and questioning Al Melling's ability to design a sound engine.
The Cerbera was a great car with a great engine. Period. If it had a Chevvy in it it would have been a completely different beast and I for one am glad it never happened. The AJP8 is a truly great engine and apart from the very first examples was reliable too. When sported the Speed Six is also a truly great engine. Completely different to a Chevvy but then if everything was the same it would be a boring world.
I don't hear many people suggesting Ferrari should swap their engines for a Chevvy. It's the same principle but people seems to accept massive engine bills from prancing ponies.
By the way, Wildcat's products show what the Rover is capable of with some development money spent on it.
Having said this please don't start slagging off the Rover V8 and questioning Al Melling's ability to design a sound engine.
The Cerbera was a great car with a great engine. Period. If it had a Chevvy in it it would have been a completely different beast and I for one am glad it never happened. The AJP8 is a truly great engine and apart from the very first examples was reliable too. When sported the Speed Six is also a truly great engine. Completely different to a Chevvy but then if everything was the same it would be a boring world.
I don't hear many people suggesting Ferrari should swap their engines for a Chevvy. It's the same principle but people seems to accept massive engine bills from prancing ponies.
By the way, Wildcat's products show what the Rover is capable of with some development money spent on it.
I am no engine expert, but assuming that the Chevy engine is as good as everyone says, I cant see why TVR would have wanted to develop its 'own' powerplants that suck up resources and have a poor reputation for reliability. Surely better for TVR to concentrate on fantastic car designs and interiors, and buy in the engine from a reliable third party?
GasBlaster said:
I am no engine expert, but assuming that the Chevy engine is as good as everyone says, I cant see why TVR would have wanted to develop its 'own' powerplants that suck up resources and have a poor reputation for reliability. Surely better for TVR to concentrate on fantastic car designs and interiors, and buy in the engine from a reliable third party?
This is a newly designed chevy. I once heard that tvr approached GM when GM started designing it but they couldn't afford to pitch in and buy/commit to an unknown engine. I still think they are using it in secret or planning to.
Boosted.
cyberface said:
The 5 litre variants also had enough poke to ask questions of the chassis.
Why do you say that? The 500 powered cars are not generally regarded as being over-powered, my V8S had a similar power-to-weight ratio in NA form and could put down full power in most gears most of the time, it was definitely power limited rather than grip or handling limited. It now has substantially more torque and needs rather less provocation to spin the wheels in the lower gears, still it is power limited most of the time and feels as if it could still use a lot more power.
bit of a hornet's nest boys. The main point as I see it is that the chevy lump, or a ford for that matter could have continued the V8 tradition in a reliable and cost-effective way, if anything making the latest cars easier to live with than griffs and chimps.
The rover lump originated at buick, so buying in a different yank design, fettled at TVR power, would have continued the great trans-atlantic tradition.
the original griff had a ford 289, and look at the Cobra.
The rover lump originated at buick, so buying in a different yank design, fettled at TVR power, would have continued the great trans-atlantic tradition.
the original griff had a ford 289, and look at the Cobra.
skyedriver said:
I thought I had it all for today when someone over here asked who Gordon Murray was . . . But surprise surprise . . .
He was the guy who invented the Murray Mint, or was that Murray Walker?
Oh no he invented Walkers Crisps didn't he?
Oh Gordon Bennett!
Here we go!
jamieheasman said:
A very nice conversion, well planned and executed.
. . .
I don't hear many people suggesting Ferrari should swap their engines for a Chevvy. It's the same principle but people seems to accept massive engine bills from prancing ponies.
That's spot on. TVRs have TVR-engines these days.
vjj said:
The original [60s] Griff had a Ford 289, and 'looks' like a Cobra.
Ah, that'll explain my picpost of that luvly red one . . . 289.
Miguel said:
Simple Q: why a Chevy and not a Ford - say - 4.7?
Pushrod engines have two advantages over OHC engines-especially in such an application-where it's clearly a tight fit and weight (along with weight distribution) is also a major concern. Those advantages are packaging and weight. Pushrod engines have lighter, lower, and simpler heads, making these engines significantly lighter and physically smaller than even a SOHC engine of similar displacement. They are also cheaper, to boot.
So why not go with a Ford engine? It's a matter of philosophy-Ford's versus Chevy's. In the 1990's. Ford decided to completely give up on the pushrod V8, replacing it with a series of SOHC (2 and 3 valves) and DOHC (4 valves) 4.6 and 5.4 liter V8 engines. You have more expensive, smaller displacement engines that produce less power in stock form and are more expensive than a comparable Chevy.
. . . Going with a Ford 4.7 (289) or 4.9 (302) gets you an engine that is basically, at best, a somewhat updated, fuel-injected version of a forty year old engine, much like the L98 Chevy's-the last Gen 1 Chevys and TVR's Rover/Buick (sorry, couldn't resist) V8's.
Miguel
Sorry guys, "Ford 4.7 (289) or 4.9 (302)" are the golden oldies and I didn't mean those OHVs to come back. It's the 4.6 / 5.4 - like in the new Muscles and the MG X Power SVR - that could do a great job here.
Doesn't the K'egg use it? Ford GT has that 5.4 even turboed. Enough possibilities to explore. When an AJP8 is out of the question TVR could have a look at those Fords . . .
Except the cammers are very fat and heavy when compared to a bigger capacity chevy.
They are also limited for future development. With the chevy you seem to get a new evolution every couple of years. So there were 5.7 variants, a 6.0 varient and now a 7.0 variant. Plus there are the diy variants up to 454 ci or thereabouts all from the basic small block engine casing.
Several years ago I considered a cammer and then I saw my first lsx.
Boosted.
They are also limited for future development. With the chevy you seem to get a new evolution every couple of years. So there were 5.7 variants, a 6.0 varient and now a 7.0 variant. Plus there are the diy variants up to 454 ci or thereabouts all from the basic small block engine casing.
Several years ago I considered a cammer and then I saw my first lsx.
Boosted.
[quote=vjj]this is surely what TVR should have done years ago. These GM 5.7 engines are extremely cheap, powerful and reliable, making a mockery of TVR's torqueless 4.2 and 4.5 v8's and straight 6's.They could have bought them in for a fraction of the development costs of the unreliable monsters that surfaced from mr melling. [quote=vjj]
I've heard that the chevy 5.7 needs to be revved to get the best out of it's power delivery and don't feel torquey enough down low. Mind you, after what I'm used to driving I'm sure I wouldn't notice this. The other thing is that there have been many complaints about the engine (as fitted to holden commodores from 1998 onwards) being an excessive oil drinker, with many engines being replaced by dealerships for this problem.
I've heard that the chevy 5.7 needs to be revved to get the best out of it's power delivery and don't feel torquey enough down low. Mind you, after what I'm used to driving I'm sure I wouldn't notice this. The other thing is that there have been many complaints about the engine (as fitted to holden commodores from 1998 onwards) being an excessive oil drinker, with many engines being replaced by dealerships for this problem.
Forget the girly LS6 Z06 engine then if you want more power check out the new LS7.
www.corvettemuseum.com/specs/2006/LS7.shtml
My understanding of the requirement for the LSx to require more revs to perform is that there is significantly more power available up to the 6K+ redline that the low end appears less torquey, however in comparison with previous engines it has the same if not more power down low. Its just that the top end is there in spades whereas before this was not the case.
www.corvettemuseum.com/specs/2006/LS7.shtml
My understanding of the requirement for the LSx to require more revs to perform is that there is significantly more power available up to the 6K+ redline that the low end appears less torquey, however in comparison with previous engines it has the same if not more power down low. Its just that the top end is there in spades whereas before this was not the case.
vjj said:Why do you say that? The Rover V8 has a superb reliability record and I don't hear stories of them going bang left, right & centre. Indeed, the worst I've had happen to my 500 in over 4 years of ownership is a cracked head which was easily weld-repaired by TVR Power.
At the rate Griff and Chimaera 500's go 'bang' that day may come sooner than we think.
"I've heard that the chevy 5.7 needs to be revved to get the best out of it's power delivery and don't feel torquey enough down low. Mind you, after what I'm used to driving I'm sure I wouldn't notice this. The other thing is that there have been many complaints about the engine (as fitted to holden commodores from 1998 onwards) being an excessive oil drinker, with many engines being replaced by dealerships for this problem."
That was true of some of the early engines with poor piston ring seal and breather systems. It's sorted now as far as I'm aware.
"My understanding of the requirement for the LSx to require more revs to perform is that there is significantly more power available up to the 6K+ redline that the low end appears less torquey, however in comparison with previous engines it has the same if not more power down low. Its just that the top end is there in spades whereas before this was not the case".
I agree totally. They can make over 300 lbs ft at 2100 rpm with a cam swop, then it just rises. Torque is everywhere with these engines.
LS7, I've managed to get some ls7 stuff which I can build into a Darton 427. I'll get the best of both worlds
Boosted.
That was true of some of the early engines with poor piston ring seal and breather systems. It's sorted now as far as I'm aware.
"My understanding of the requirement for the LSx to require more revs to perform is that there is significantly more power available up to the 6K+ redline that the low end appears less torquey, however in comparison with previous engines it has the same if not more power down low. Its just that the top end is there in spades whereas before this was not the case".
I agree totally. They can make over 300 lbs ft at 2100 rpm with a cam swop, then it just rises. Torque is everywhere with these engines.
LS7, I've managed to get some ls7 stuff which I can build into a Darton 427. I'll get the best of both worlds
Boosted.
dinkel said:
Sorry guys, "Ford 4.7 (289) or 4.9 (302)" are the golden oldies and I didn't mean those OHVs to come back. It's the 4.6 / 5.4 - like in the new Muscles and the MG X Power SVR - that could do a great job here.
I have no problem with the Ford engines, but as I said before, those engines are neither light nor small. OHV engines are better for light weight and packaging. Given the choice, I'd take 5.7 or 6 liters of Chevy (LS1/6 or LS2) than 4.6 or 5.4 of Ford. BTW the 5.4 is essentially a stroked, tall block version of the 4.6-yes, their bores are identical. It truly has a truck-like bore to stroke ratio and an enormous stroke.
dinkel said:
Doesn't the K'egg use it? Ford GT has that 5.4 even turboed. Enough possibilities to explore. When an AJP8 is out of the question TVR could have a look at those Fords . . .
The K'egg (I can't spell it either
) has a supercharged 4.6. The Ford GT has a purpose built all-aluminum DOHC supercharged 5.4. Sure, the engine is based on 4.6/5.4 engine architecture, but many of the major parts used in this application are built specifically for it. It's major bucks. Also, these cars are far bigger and heavier than any TVR. I'd also guess that engine size is less of a problem with mid-engined cars. The MG X is front-engined, but it's bigger than any TVR I remember.
In the past, Mustang Cobra's have been offered with NA DOHC 4.6 producing 305 or 320 hp (aluminum block) or a supercharged, iron block version with 390 hp. You can also buy a 5 liter version of the DOHC that puts out something like 420 hp as a crate engine. This one costs about 3 times as much as an LS1/6 crate engine. Pick your poison.
Oh, and I doubt that Ford will ever offer the Ford GT powerplant as a crate engine, but if they do, the price will be impressive.
On a different note, some day I hope to make it across the pond to England so that I can drive a Cerbera... and NO, I don't want anyone to put a Chevy engine in it.
Miguel
While we're on the topic, i think I'll add some more fuel to the fire: what about a new Chrysler 5.7 Hemi conversion? Sure it doesn't even have hemispherical combustion chambers, and it's down 50kW (oops 70hp) down on the Chev, but why not? Or, why not even a Viper crate motor? Only the clinically insane need apply.
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