interesting speed 12 info
Discussion
i was just reading the new news on the speed12.info site and it was mentioned that as the race car was developed new heads were created for it which were bucket design which gets rid of the finger followers and the road car 12 is now running those heads. could this mean that the most powerfu TVR engine ever could be quite reliable by getting rid of what seems to be the same problem popping up on here.
as it is essentially two speed6's joined together preumably this could be used on a normal speed 6
as it is essentially two speed6's joined together preumably this could be used on a normal speed 6
rev-erend said:
I often wondered why AM did not go for a bucket & Shim design ..
Simple really, finger followers permit space saving over traditional bucket tappets by allowing higher valve speeds and greater lift with no need to increase tappet diameter. They're also more stable because there's no possibility of the cam lobe rocking the tappet.
You see, many production overhead-cam engines use roller-finger-follower designs since they reduce friction dramatically and can also greatly reduce the valvetrain mass above the valve. This allows stable operation at higher rpm with less parasitic loss.
Virtually all Formula One teams are now believed to use a roller-finger follower valvetrain design in their current engines to achieve similar benefits. Ok, its a given the speed 6 is no ferrari engine, but the attempt was there, where else in the world will you find a straight-6 pushing 400 horses?
The old-school bucket design works, but it has its limits, oh and the speed 12 engine was never a solid engine
although she is now back on the roads with a complete rebuild, only time will tell how solid the engine with the newly designed heads is I'm very keen on seeing the speed 12 hit an independant rolling road in the near future so we can see what she's producing now after the head re-design....
SXS said:
You see, many production overhead-cam engines use roller-finger-follower designs since they reduce friction dramatically and can also greatly reduce the valvetrain mass above the valve. This allows stable operation at higher rpm with less parasitic loss.
Quite an interesting article on f1 valve trains:
http://www.indiacar.com/nfs/technical/pvengine.htm">www.indiacar.com/index2.asp?pagename=http://www.indiacar.com/nfs/technical/pvengine.htm
SXS said:
Ok, its a given the speed 6 is no ferrari engine, but the attempt was there, where else in the world will you find a straight-6 pushing 400 horses?
or 380 as the website now says, a massive 20 more than BMW manage with 800cc less...
m12_nathan said:
You see, many production overhead-cam engines use roller-finger-follower designs since they reduce friction dramatically and can also greatly reduce the valvetrain mass above the valve. This allows stable operation at higher rpm with less parasitic loss.
Quite an interesting article on f1 valve trains:
http://www.indiacar.com/nfs/technical/pvengine.htm">www.indiacar.com/index2.asp?pagename=http://www.indiacar.com/nfs/technical/pvengine.htm
SXS said:
Ok, its a given the speed 6 is no ferrari engine, but the attempt was there, where else in the world will you find a straight-6 pushing 400 horses?
or 380 as the website now says, a massive 20 more than BMW manage with 800cc less...
You just don't get it do you...? The S6 is a conventional N/A engine set up WITHOUT any clever variable valve timing trickery as has the Beemer. The S6 produces very respectable HP figures because of its overall design as a whole package utilising simple individual injector throttle bodies...Thats what makes it impressive in comparison.
I get "it", if "it" is that the s6 is a good engine but not the miricle in specific output people seem to claim.
What has peak power got to do with variable valve timing? Midrange and idling, torque curve yes, but peak power? The s54 doesn't even have independant throttle bodies (individual but not independant) yet still makes much more power per litre. Maybe the S6 isn't actually the race engine people claim it is? A great engine maybe but these forums are full of people claiming it is something amazing to get 380bhp from a 4l "race engine" and it isn't. Bit of a reality check, that's all
What has peak power got to do with variable valve timing? Midrange and idling, torque curve yes, but peak power? The s54 doesn't even have independant throttle bodies (individual but not independant) yet still makes much more power per litre. Maybe the S6 isn't actually the race engine people claim it is? A great engine maybe but these forums are full of people claiming it is something amazing to get 380bhp from a 4l "race engine" and it isn't. Bit of a reality check, that's all
m12_nathan said:
I get "it", if "it" is that the s6 is a good engine but not the miricle in specific output people seem to claim.
What has peak power got to do with variable valve timing? Midrange and idling, torque curve yes, but peak power? The s54 doesn't even have independant throttle bodies (individual but not independant) yet still makes much more power per litre. Maybe the S6 isn't actually the race engine people claim it is? A great engine maybe but these forums are full of people claiming it is something amazing to get 380bhp from a 4l "race engine" and it isn't. Bit of a reality check, that's all
That is exactly what I was getting at....as an over all package it does produce respectable performance CURVES, and is what puts it ahead of the competition. As I am sure you know there is a compromise between peak power and torque and where it is produced. The S6 produces both as very impressive figures using conventional methods. I therefore disagree with you, but I cant be ar5ed getting into a petty argument with you. I am too busy earning wads of doh to pay for an even better power spread from the S6.....
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