fuel Posted February 27, 2008 Author Share Posted February 27, 2008 I I'm sorry but whats complicated about this? Also Can't run twinscroll on Six's then? There's nothing overly complicated about this - I was just wanting to make sure I had the manifold routed correctly to take advantage of a twin scroll turbo. Link to comment Share on other sites More sharing options...
thegreatestben Posted February 27, 2008 Share Posted February 27, 2008 Hahaha I didn't mean you I meant shg with his rotary simplicities Link to comment Share on other sites More sharing options...
fuel Posted February 27, 2008 Author Share Posted February 27, 2008 oh, well in that case, shgwag can stfu. Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted February 27, 2008 Share Posted February 27, 2008 dont you have issues with ..well poping ?oris this the first set you have done ? no real extreem pressure. we will c i spose. turbo and dumppipe will be braced to help it not crack. Link to comment Share on other sites More sharing options...
Guest vvega Posted February 27, 2008 Share Posted February 27, 2008 normally ex and intake match 1:1 so if you run 10psi you will have abotu 10psi in teh ex so yeah fuck all...but its enough seen the results of mild steal ex manifolds...normally ends up in a engine fire when they get real hot and pop teh molten steel goes everywhere and shit catches fire ..the other solution is to have it ceramc coated....that works well v Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted February 27, 2008 Share Posted February 27, 2008 im using a special cam ect to prevent unburnt fuel going into exhaust. will see how it goes i suspose. Link to comment Share on other sites More sharing options...
lowlancer Posted February 28, 2008 Share Posted February 28, 2008 Dash engines use similar shit cept it's called pulse length or some shit Link to comment Share on other sites More sharing options...
Guest vvega Posted February 28, 2008 Share Posted February 28, 2008 im using a special cam ect to prevent unburnt fuel going into exhaust. will see how it goes i suspose. just ceramic coat it ...just for insurace then youll have no worries....they coat teh inside as well as teh outside Link to comment Share on other sites More sharing options...
Burntrubber Posted February 28, 2008 Share Posted February 28, 2008 Shouldn't use anything thiner than 2.5mm mild steel for turbo manifold's. A guy I work with made one years ago out of thin tube for a CA18DET it sagged and cracked in about three weeks of town driving! I've made 6 or so from schedule 40 steam tube and there all good so far Link to comment Share on other sites More sharing options...
fishtailfred Posted March 14, 2008 Share Posted March 14, 2008 Four things : 1. the point of a turbo is to have the exhaust gases expand as they go through the turbine wheel. if there is a big open space before the turbo (read conventional single scroll and the merge area before it, the gases expand there and the energy delivered to the turbo is less. by keeping them together right up until the wheel, you keep velocity and energy up and keep restriction low. basically you can have top end and bottom end from a turbo that is twin scroll, but the manifold is more of a pain if you want to do it right. if you dont do it right, the thing will spool worse than a single scroll that is comparable. 2. no one complained when they saw my manifold and i said "1.6mm maaaaate". ALL manifolds should be extensively braced. even thick walled ones. the stresses on the studs are too high otherwise. if you don't brace it you are asking for trouble. conversely if you brace a 1.6mm walled one well (see my brace) there is NO stress on it at all. 3. on a good setup exhaust pressure will be close to intake pressure, on a shit setup, it will be MUCH higher. i'd love to see the REST of the setups that "just burst" and i bet there was some serious restriction between turbo and inlet valves and or between turbo and ex tip and or the turbo was a small one that was choking at higher power and providing immense back pressure and associated high ex valve temps and detonation prone operation. My ex pressure is about 19psi for 17.5psi of boost. I reckon thats pretty good. On a lousy setup, it might have required 40psi to reach that. 4. lovely work on that zetec? manifold very nice. Thats all folks Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted March 14, 2008 Share Posted March 14, 2008 sweet man yea forsure its braced from engine mounts up holding weight of turbo and also the dump pipe braced to the bellhousing bolts. and nah its for ma turbo pinto. but that gives me an idea tho! (turbo zetec lotus?? hehe) Link to comment Share on other sites More sharing options...
Guest vvega Posted March 14, 2008 Share Posted March 14, 2008 Four things :1. the point of a turbo is to have the exhaust gases expand as they go through the turbine wheel. if there is a big open space before the turbo (read conventional single scroll and the merge area before it, the gases expand there and the energy delivered to the turbo is less. by keeping them together right up until the wheel, you keep velocity and energy up and keep restriction low. basically you can have top end and bottom end from a turbo that is twin scroll, but the manifold is more of a pain if you want to do it right. if you dont do it right, the thing will spool worse than a single scroll that is comparable. kinda right win scroll turbine housing. The TST housing derives its name from the geometry of the exhaust gas inlet into the turbine. Two different-sized scrolls are generally used, a primary and a secondary. Typically, the primary is open for low-speed operation, and both for high-speed use. This creates the ability of the TST to be a small A/R housing at low speeds and a large A/R at higher speeds.TST designs are of merit in that they offer a better combination of low-speed response and high-end power. It would be difficult to configure the unit to control boost by effectively varying A/R. A wastegate is therefore still necessary to control boost pressure. Simplicity of the twin scroll turbine housing is its big selling point. Link to comment Share on other sites More sharing options...
fishtailfred Posted March 18, 2008 Share Posted March 18, 2008 I've gotta say, I have no respect for corky and that book. It is so full of blatantly wrong stuff it's near useless. It IS good as a break in book for boost noobs though What he wrote there sounded like it was written about VGT/VNT stuff? Twin scroll is good for spool for the same reason huge manifolds like mine are bad for spool. Internal volume and separation/lack of. Link to comment Share on other sites More sharing options...
forced Posted March 18, 2008 Share Posted March 18, 2008 I've gotta say, I have no respect for corky and that book. It is so full of blatantly wrong stuff it's near useless. It IS good as a break in book for boost noobs though What he wrote there sounded like it was written about VGT/VNT stuff? Twin scroll is good for spool for the same reason huge manifolds like mine are bad for spool. Internal volume and separation/lack of. Totally agreed with there. That's the trouble with quotes. The trouble using mild steel is that it rusts. It's OK when the manifold is new but if you strip the car, leave the manifold in the (damp) garage for a few weeks, you'll see flakes of rust falling off from the inside when you give it a bang. Rust flakes and turbines don't get on well together. I'm not talking short term here but long term. That's why I used stainless for mine. It's not quite so bad these days with unleaded but leaded fuel is deadly for rusting of exhausts. Why do the manufacturers always use either cast iron or stainless? Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted March 18, 2008 Share Posted March 18, 2008 I've gotta say, I have no respect for corky and that book. It is so full of blatantly wrong stuff it's near useless. It IS good as a break in book for boost noobs though What he wrote there sounded like it was written about VGT/VNT stuff? Twin scroll is good for spool for the same reason huge manifolds like mine are bad for spool. Internal volume and separation/lack of. Totally agreed with there. That's the trouble with quotes. The trouble using mild steel is that it rusts. It's OK when the manifold is new but if you strip the car, leave the manifold in the (damp) garage for a few weeks, you'll see flakes of rust falling off from the inside when you give it a bang. Rust flakes and turbines don't get on well together. I'm not talking short term here but long term. That's why I used stainless for mine. It's not quite so bad these days with unleaded but leaded fuel is deadly for rusting of exhausts. Why do the manufacturers always use either cast iron or stainless? a warrenty i think. try find a factory stainless steel turbo manifold? Link to comment Share on other sites More sharing options...
forced Posted March 18, 2008 Share Posted March 18, 2008 Mitsi GTO front turbo manifold is fabricated stainless. Rear one is cast. BTW anything you read about differential pressures between intake and exhaust manifolds, it's all BS. Exhaust flows in pulses, so does intake. Measuring average pressure at the turbo exhaust is not measuring instantaneous pressure after the valve, nor is measuring intake pressure in the manifold the same as measuring instantaneous pressure in front of the intake valve. Think of it as measuring a differential electrical signal that's pulsed DC using a DC voltmeter. All you get is an average reading. Should be measuring it with an oscilloscope. Link to comment Share on other sites More sharing options...
Testament Posted March 18, 2008 Share Posted March 18, 2008 Yeah havent seen a factory stainless turbo manifold. And well casting = mass production/ease of manufacture. I've got a steampipe turbs manifold thats been kicking around my garage for about 4 years, inside is still full of carbon/soot no real rust. I'm sure if i I cleaned it and it got wet or the air got really really damp it might start to make big flakes, but its pretty unlikely to corrode significantly in a dry place with a layer of soot on it, or on your car where it gets hot and has a layer of soot on it. Link to comment Share on other sites More sharing options...
fishtailfred Posted March 18, 2008 Share Posted March 18, 2008 BTW anything you read about differential pressures between intake and exhaust manifolds, it's all BS. I dunno about you, but I didn't read about it, I did it... Exhaust flows in pulses, so does intake. Yes, but what determines how efficiently said pulses move?? Measuring average pressure at the turbo exhaust is not measuring instantaneous pressure after the valve, nor is measuring intake pressure in the manifold the same as measuring instantaneous pressure in front of the intake valve. Well bugger me, all these years I've been using MAP sensors to run my engines I was wrong and it wasn't working.... What do you suppose causes those pulses of flow on the intake side dude?? Thats right, the pressure differential between plenum and cylinder at the time when that valve opens. What do you suppose determines that figure? Average pressure and any resonant pulses present from geometry and speed. Average pressure on BOTH sides is a VERY good indicator of what is going on. It is not the whole story, BUT, it IS consistent, because the rest of the story is consistent and determined by geometry and speed. Think of it as measuring a differential electrical signal that's pulsed DC using a DC voltmeter.All you get is an average reading. Should be measuring it with an oscilloscope. Which, if you want to measure heat in a resistor is ideal... (assuming your meter is RMS...) It's perfectly valid and a VERY good indicator of overall flow efficiency between air filter and exhaust tip... As for rust, ya don't think the fact that WATER is one of the main things you get in your exhaust has anything to do with it do ya? My thin wall POS manifold is sitting for two years right now. When I fire it up in another year to year and a half and cruise down the road and hit boost, I will not be too concerned about rust... why is that? The other main thing you get in your exhaust is CO2. There is next to no O2 left in that exhaust. Heat + O2 = rust. Take away either and you have slow slow rust. Also, I'm fairly sure that not too many people that just did a nice job on their custom mani would plonk it down in a puddle of mud in their cow shed for a month and hope for the best Link to comment Share on other sites More sharing options...
Guest vvega Posted March 18, 2008 Share Posted March 18, 2008 I've gotta say, I have no respect for corky and that book. It is so full of blatantly wrong stuff it's near useless. It IS good as a break in book for boost noobs though What he wrote there sounded like it was written about VGT/VNT stuff? Twin scroll is good for spool for the same reason huge manifolds like mine are bad for spool. Internal volume and separation/lack of. well mate i dont read stuff i do it ive chpped up a couple of twin scroll ex housings and well hes right its quite eazy to see teh differance in a/r outright wouldnt have posted it if i hadent doen it for myself ive made large minifolds that have spoooled faster than smaller ones the concepts on size been a factor is the old way of thinking and has since been moved on from...... to much google i think for you the rest of it...well i hate to say it but forced is closer than you....and fuck that decieingly painful it is all about the pulse timing but then whats the point in argueing on the enet reality is right now you hittting teh search button in google tring to find the next thing to throw...... ...........perhaps you shoudl tri teh i feel lucky button this time Link to comment Share on other sites More sharing options...
Guest vvega Posted March 18, 2008 Share Posted March 18, 2008 Also, I'm fairly sure that not too many people that just did a nice job on their custom mani would plonk it down in a puddle of mud in their cow shed for a month and hope for the best ??ive seen farmers do better welds than that with there arc welders...so IMO its not as far from the cowshed as you would have liked it to be pritty sure teh volume in those pipes would be quite high as well ...so um really dosent line up with yoru posts abotu it i guess google has taught you more since then lol Link to comment Share on other sites More sharing options...
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