stop quoting every bloody post!!!

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need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Your right v8 from 2006 to restrict power and rev limited reduced to 18000 in 2009.

I suppose its the nature of very over square engine, ie, F1, and motorcycle engines, both road and mx. They get the capacity from a huge bore but short stroke, so that they can use huge valves, butttt, they rev to the moon and back too, not necessarily because of the actual bore x stroke ratio, but the size of the valves in relation to the capacity. I see that 1.4 16v engine you have done sandy, more over square than stock, is that to get the valve size up? what does it rev to?

a 450cc CRF honda motocross bike has a 98mm bore i think, 4 x 450cc is 1800cc, (remembering a 1905cc xu is 83mm bore) they make circa 55bhp at the wheels, as stock, 4 x 55 = 220bhp.

The other way i "thought" about using big valves is, although you have a bigger 'hole' so to speak, you also have a bigger plug for the hole, that plug isnt removed, just moved out the way, a restriction in itself no?

Also, the bigger the valves, the closer they are together, to exaggerate, imagine they where almost touching when opening( )( ), that gap in between the valves is trying to pass air, but it cant, because there is another valve in the way, if you have gained a theoretical 10% area in valve open area at max lift, what area % is actually useful?. ie, letting air flow into the cylinder, not being blocked off?

If the valves are further apart (ie stock sized as opposed to over size) ( ) ( ) , the gap between them is going to flow more air than the smaller gap between the bigger valves?

Just thoughts.

I think this is where engine design development gets very complicated and very expensive! I think Sandy is bag on. I mean say you want to develop an engine- how many heads would you need to experiment on to start with? 5? 10?

Maybe a silly question Sandy- but do you think non circular valves may be the way forward for someone wanting the ultimate race head? (obviously very expensive to have made up!) And with regard to the engine above with the better top end performance- do you think there is any scope to improve the midrange with some variable geometry intake? I don't know if that is prohibited in that class.

This is my thoughts on this, and may be totally wrong.

Non circular valves would be main stream now if they worked, not only are you taking the uniform shape of them (to correspond with the port shape almost always being round or there abouts, ie d shaped) and maybe adding 'corners', to give points of low and or high pressure and un-even flow, you have got to try and seal them also, and control their movement (twisting), a valve also acts as a heat transfer unit remember, i think in an 'ideal' valve area scenario you would have 2 half circular valves, but you have got to remember shielding effect and flow. Also the corners of the valves, all be it, i would presume radiused well, would most likely be hot spots, and how strong they would be i dont know.

Its like when honda used oval pistons in some GP bike, it was a pain in the arse to do and didnt work well enough to warrant the extra trouble.

Yamaha moved from 5 valves per cylinder to 4 on both the R1 and R6 i believe, i cant see that being a step backwards, i dont know the ins and outs of it, but even if valve area was reduced the 4 valve head performed better, made more power and torque i believe coupled with other changes also.

I have seen an engine design where instead of cams and valves, it used small crank shafts and pistons as valves. So the pistons are seemingly hanging from where the cams would normally be, when these cam/cranks are at their BDC the port is totally open and there is no restriction to the flow into the cylinder, then when at TDC they now form the combustion chamber itself.

Someone design an engine that uses butterflies instead of valves, no worry about lift figures then, could have them electronically motor controlled, no rotating camshafts, so reduced inertia, and fully adaptable for 'duration' and i suppose their equivalent of lift, being opening angle.

What is a normal Tu 1.4 bore stroke though, and valve sizes? And what is the head off of that sandy is using and valve sizes, im not all that up on my TU stuff.

The Honda engines i refer to are the Motocross singles, thats what i am familiar with, i dont know about the car engine. Hmm, thats an interesting idea, V-Tec in motocross! Could be the next big selling point when everyone is bored of fuel injection.

Hondas "oval pistoned bike" was a combination of development and showing off! The rc45 rvf had oval pistons so they could fit 8 valves per cylinder. Awesome bit of kit though.

Also vtec is a very clever system apart from the lack of torque they produce, I want an ek9 soo bad

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banned for drifting. back in the s**tbox scene.

I shall have to have a hunt around, see what i can find, just thought it was an interesting idea. I suppose there is nothing now that hasnt been done or tried.

K20A is the same 86x86 as an XU10 aren't they Sandy? what is it about them that makes then rev so much?

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.