BRAAP, 1 fast Z, think you guys can manage this?

[thehelix112]

What dyno do you require that you would accept as proof?

 

Also, just to be clear (again), I wasn't saying that Baz was lying, but that others were taking what he said a step or two farther.

 

Tim, I'd guess anything thats not inertia based. I've heard good things about Dyno Dynamics dynamometers.

 

Or failing that, if we're mostly concerned with engine output, how about.. an engine dyno? (shock, horror). Its annoying reading ``my car makes 50hp at the wheels, soo.. multipled by X-figure-pulled-out-of-my-arse means my A12 is making a bajillion hp''.

 

Dave

[Xnke]

Hmmm....so raising the ports, and using a Mikuni-style manifold would help improve flow just as much as moving the valves over. Interesting....having just picked up two SU manifolds, and a complete L24 with complete Mikuni triple carb setup, Maybe a cut 'n' splice on those E88 manifolds to more closely resemble the Mikuni style manifold would be of benifit?

 

()BTW, the Mikuni stuff is for sale, very dirty but certainly usable.(Plug>)

[Tony D]

I said moving the ports up and using a Mikuini Style Manifold would be easier and probably result in similar valve-approach angles as tilting the valve.

 

One would have to draw it out to see if the approach angles could be made using this approach.

 

Drawing board and drafting machine are 1/2 the world away right now, so I can be of no help till I return home to check it in that manner.

 

Someone with CAD could probably do it far quicker.

[turbobluestreak]

I've been playing around with this since this thread was started. I think you guys are thinking about the wrong axis that the valve is being titled on. Tilting the valve from top of the stem of the intake to the center of the bore showed and average of 16cfm increase when compared to other ports I've modeled. For every 1 deg of title we gain about 2mm of extra valve de shrouding, so a stock L28 86mm bore would have similar valve shrouding as a 90mm bore would. Drawbacks are that anything larger then stock valves might not work because they might hit on overlap. I would need a cam profile to see overlap and check the distance between the valves.

 

As for the debate of raising the port or angling the valve I would leave the valve were it is and raise the port. Titling the valve changed the fluids chamber entry to the point it was hurting flow. The valve would need to be titled and then shifted back to gain any flow assuming you are rotating the valve about the top of the stem to limit changes to the cam and rocker geometry.

 

This may still prove to not be worth any gains I've yet to model any rocker arm geometry to see what happens to the rest of the valve train when tilting of the valve.

 

Does anyone have any thoughts or further suggestions on valve tilting?

 

tbs