fishtailfred Posted March 19, 2008 Share Posted March 19, 2008 FFS, pull that cucumber OUT of your arse before it gets stuck in there and you end up on the xray teams wall of funny shit that walked in awkwardly... You are right that spooling a turbo is all about pulses. Particularly, it is about the VELOCITY of those pulses when they pass through the turbine, and the delta velocity between entry and exit. Of course you could build a big mani that spooled better than a small one. It's possible to build anything particularly shit if you try hard enough. Like all things, manifold design is a compromise. Take it to the extreme, perfectly smooth, optimal design, 1/4 of a mile from the engine and what do you get? that's right, poor spool. The pulses no longer carry the energy that they did when they left the exhaust ports. Drop a blob of splatter (i'm sure you can find a nice big blow out style one ) in a smooth piece of water. it is no coincidence that the waves are biggest and most most powerful in the epicentre. As for pulse timing, that is mainly relevant to NA setups. Much less scavenging goes on in a turbo manifold in boost. Consider the RPM of the turbine and you will see that relative timing of the leading edge of a pulse could fall on any particular blade, and of course, it doesn't matter which one anyway. As for google, believe what you want. google is for finding out about things that you don't know about. When you studied fluid dynamics at university, google is not where you get your turbo spool information Cucumber > OUT!! Link to comment Share on other sites More sharing options...
forced Posted March 19, 2008 Share Posted March 19, 2008 . Much less scavenging goes on in a turbo manifold in boost. !! The scavenging is done by the reflected wave which is low pressure. It's exactly the same turbo'd or not. The turbine acts as a flywheel to actually increase the scavenging effect. Link to comment Share on other sites More sharing options...
forced Posted March 19, 2008 Share Posted March 19, 2008 Exhaust flows in pulses, so does intake. Yes, but what determines how efficiently said pulses move?? Camshaft Link to comment Share on other sites More sharing options...
Guest vvega Posted March 19, 2008 Share Posted March 19, 2008 forced as much as i think your a twat......i think you have this covered cant down a man when hes right lol Link to comment Share on other sites More sharing options...
fishtailfred Posted March 19, 2008 Share Posted March 19, 2008 The scavenging is done by the reflected wave which is low pressure. And the venturi effect... which is less effective when overall pressure is higher from a poor setup. Camshaft Wrong, that is what determines the pressure profile of the pulse. That pressure is acting with or against whatever is in the manifold at the time. Remove your pulsations and resonances for a second and concentrate on the MAJORITY of the effects at hand. = sheer restriction to flow. push the valve to a fixed maximum lift, pull the piston out and stuff a huge vac pump below it, then vary the air pressure between 0kPa and 400kPa and see how much air moves through that orifice. That is the majority of it. You can ditch all your resonances and expose you ports to the world and still make decent torque, or you can spend millions on research and get the figures up from 80% VE to 120% VE... (way less range than that) 80 is still greater than 120 - 80. Fred. Link to comment Share on other sites More sharing options...
Guest vvega Posted March 19, 2008 Share Posted March 19, 2008 The scavenging is done by the reflected wave which is low pressure. And the venturi effect... which is less effective when overall pressure is higher from a poor setup. Camshaft Wrong, that is what determines the pressure profile of the pulse. That pressure is acting with or against whatever is in the manifold at the time. Remove your pulsations and resonances for a second and concentrate on the MAJORITY of the effects at hand. = sheer restriction to flow. push the valve to a fixed maximum lift, pull the piston out and stuff a huge vac pump below it, then vary the air pressure between 0kPa and 400kPa and see how much air moves through that orifice. That is the majority of it. You can ditch all your resonances and expose you ports to the world and still make decent torque, or you can spend millions on research and get the figures up from 80% VE to 120% VE... (way less range than that) 80 is still greater than 120 - 80. Fred. ive read it 3 times and non if it make sence you have all the right words..but thats it the scavanging is created by the ventury efectt and that is what happens on teh backside of teh wave(vacum) as you said..but its all one effect ...not seperate the next papraghraph you say rmove alkl that..and similate a pistin...why ??? thats niot what were talking about ...dont tri to change subject forced is dead right all pulses are directely related to the openign of teh valve ...even you say it but you just cant dmit your wrong...or you just wanna argue some more you said pure it simp[le its what created teh profile of teh pulse...welll that is the pulse..its every cratiristic of the pulse twistign what other people say to make you seam right dosent mean that you win a arguement... jjust means yoru a wanker for not mannign up and saying yoru wrong Link to comment Share on other sites More sharing options...
Honda Ass Dragger Posted March 19, 2008 Share Posted March 19, 2008 I really wonder about some people on here Build a fucking log and be done with it Link to comment Share on other sites More sharing options...
thegreatestben Posted March 19, 2008 Share Posted March 19, 2008 jjust means yoru a wanker for not mannign up and saying yoru wrong Is it really neccessary to call everyone a wanker if you don't agree with their theory? geeze Wayne Link to comment Share on other sites More sharing options...
Guest vvega Posted March 20, 2008 Share Posted March 20, 2008 its the same theroy as has been said just said differently thats what so stupid about it its arueing about nothing Link to comment Share on other sites More sharing options...
Snoozin Posted March 20, 2008 Share Posted March 20, 2008 Yeah less arguing please I AM HIGHLY STRUNG AND I HAVE A FUCKING DELETE BUTTON!!!!!!!!!! Link to comment Share on other sites More sharing options...
forced Posted March 20, 2008 Share Posted March 20, 2008 Wrong, that is what determines the pressure profile of the pulse. That pressure is acting with or against whatever is in the manifold at the time. Remove your pulsations and resonances for a second and concentrate on the MAJORITY of the effects at hand. = sheer restriction to flow. push the valve to a fixed maximum lift, pull the piston out and stuff a huge vac pump below it, then vary the air pressure between 0kPa and 400kPa and see how much air moves through that orifice. That is the majority of it. . Ahhhhhh you're describing how a flowbench works. The trouble is that a flowbench has little to do with what really goes on inside an engine, just a over simplification and a means of........ A flowbench only works in a steady state at or nearly at atmospheric pressure. A flowbench doesn't take into account momentum which is mass times velocity. Momentum is very important because for 60 to 70 % of the time there is zero flow in a port. So...... you know about fluid dynamics?? so, does air at atmospheric pressure flow in exactly the same way as air at double or even triple atmospheric pressure? I've never been able to get a straight intelligent answer on that one. Sorry for the OT wind up. Link to comment Share on other sites More sharing options...
Guest vvega Posted March 20, 2008 Share Posted March 20, 2008 double the preaure = half the wavelenght etc from memory forced you done much plasma physics ?? look up laminar flow it explains why even manifolds that are crap for "flow" still work very well v Link to comment Share on other sites More sharing options...
Hemi Posted March 20, 2008 Share Posted March 20, 2008 pissing contest , case closed . heaps of information in here but its psread about in the complete wrong way Link to comment Share on other sites More sharing options...
fishtailfred Posted March 20, 2008 Share Posted March 20, 2008 does air at atmospheric pressure flow in exactly the same way as air at double or even triple atmospheric pressure? I've never been able to get a straight intelligent answer on that one. Today is your lucky day, but I'm calling you lazy, it took about 15 seconds to find and quadruple reference this : The impact of pressure is minor and the viscosity correction for pressure is less than 10% for the gases in our calculation for pressures up to 500 psi (34.5 bar) (Crane, 1988). http://www.lmnoeng.com/Flow/GasViscosity.htm Doubling the temperature appears to increase viscosity of air by around 6% All negligible... Much like the pressure pulse resonances which are NOT the same as venturi effect. I'm not going to explain that here though. Someone is trigger happy with the delete button and they (whoever they are, without exception) can get fucked. I'll share my information elsewhere. Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted March 20, 2008 Share Posted March 20, 2008 ok blah blah 3 pages of crap in one post say how all this is going to help anyone who doesent have clue about manifolds to make a desent job. . . . Link to comment Share on other sites More sharing options...
fuel Posted March 20, 2008 Author Share Posted March 20, 2008 ^^^ what he said Link to comment Share on other sites More sharing options...
Guest vvega Posted March 20, 2008 Share Posted March 20, 2008 its not none of this is revelent to anyone that is making a manifold and most of it is just arguements of ttecnical aspects that people arnt qualified to argue over so in essance the threed is a pissing contest as has been said and utterly a waste of time to paticipat in or even read past teh fist say 5 posts Link to comment Share on other sites More sharing options...
forced Posted March 20, 2008 Share Posted March 20, 2008 I think that the most important aspect is that mild steel rusts from the inside out and .......... pretty obvious really. Post 35 or so. Link to comment Share on other sites More sharing options...
Hemi Posted March 21, 2008 Share Posted March 21, 2008 mild steel rools your face , rat manifold in yo' face rofl Link to comment Share on other sites More sharing options...
CXGPWR Posted March 21, 2008 Share Posted March 21, 2008 Stainless FTMFW, Ill Tig Weld the bitch up for yo, make it look nice & shit, polished stainless Link to comment Share on other sites More sharing options...
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