tubular manifold

[Liam 589]

Would also be interested in one.

 

[bracpan]

Work or art....I would imagine you could make a GTiR manifold for a twin scroll turbo?

 

[vpulsar]

Shroom is selling a DP one, but think they move the turbo forward.

I have a DP one sitting on my garage floor at the moment but its for an external waste gate which is also still attached. plus of cause I have a 1000 mile old GT3040 as well lol.



Rob

 

[shroom]

DP manifolds crack as well there not brilliant,

 

[Makaveli_se7en]

Am I the only one that sees a stealth group buy from an unpaid member?

 

[vpulsar]

Am I the only one that sees a stealth group buy from an unpaid member?

Who really cares as long as long as he does what he says he can and the product is of suitable quality I'm sure every will be happy apart from you maybe but that's because you're from Yorkshire and they're all depressed for good reason lol.


Rob

 

[Makaveli_se7en]

shows how much you know; I'm not from Yorkshire.

 

[shroom]

Am I the only one that sees a stealth group buy from an unpaid member?

Im not sure both Pobody and Campbellju have posted about it so they must know something we dont

 

[PobodY]

If it does turn into a group-buy we'll give Bogdan the chance to pay his membership dues first, - I'm keen on encouraging this kind of professional-quality fabrication for the GTiR, so I'm leaving it alone for now.

However, your concerns are duly noted.

 

[shroom]

I have no concern from me ;-) as you say its nice to see someone actually having an interest in the R,

 

[MarkTurbo]

Who really cares as long as long as he does what he says he can and the product is of suitable quality

I thought the same thing too Rob, i'm not sure why there is so much negativity towards somebody that has obviously got pretty decent fabrication skills and could make something that would benefit people :?

All the problems started when paid membership was brought in as all you get now is people moaning about non paid members doing this or that. This site should have been left as it was as its obvious that you get bugger all for your £20 and nobody has ever come up with an answer to where all the money goes either so you may as well go and chuck your £20 in the river :lol:

 

[RO_SUNNY]

If i will see people intersted in my product I will pay my dues as requested as it seems fair to do so.
It's fair that all the people who benefit from a forum to pay a membership.

Phil I can do whatever you need to be done as all my work until now has been only custom made (manifolds, exhausts, downpipes, intercooler piping and other pipe/tube related work )....and by the way...a twin scroll is easyer to do

So..........

I'll speak to you soon guys as for now I am hollyday but I will have access to the internet an dI will keep an eye on the forums.

 

[shroom]

I thought the same thing too Rob, i'm not sure why there is so much negativity towards somebody that has obviously got pretty decent fabrication skills and could make something that would benefit people :?

All the problems started when paid membership was brought in as all you get now is people moaning about non paid members doing this or that. This site should have been left as it was as its obvious that you get bugger all for your £20 and nobody has ever come up with an answer to where all the money goes either so you may as well go and chuck your £20 in the river :lol:

I got some money off the track day so its not all bad, suppose it could go with no fees and there would be some nice adverts on here to keep the site running, I think with optimizing the site it could be a real goldmine for searches regarding "moaning"

 

[Makaveli_se7en]

I only made the comment as if it's a proper group buy then someone should surely vet the technical merit of the product. I'm not knocking the fabrication skills or the durability of the manifolds and I have always had the upmost admiration for Bogdan's welding (although I'd love to know if the warranty is valid for cars with anti-lag!). But I think a few questions need to asked, as it appears the designs are based on simple pipe flow calculations. Comments such as "Equal length is not so important how the number of bends on each runner is." would lead me to have concerns as this is clearly only considering steady state effects. There is no point in having a tubular manifold if it's not going to be equal length, as the result is uneven back pressure across the cylinders and the loss of most of the benefits over a log design.

The sort questions I would be asking are what are the L/D ratio of the runners and was this taken from the head or the valve, how was the runner length chosen and what assumptions regarding valve timing, rpm, turbine inlet temp and pressure were made, what loss modeling was used the bends and does the design avoid reversion and if it occurs between what rev range (reversion can be a very bad thing - just ask any skyline owner that had a ceramic turbine fail and sucked back into the engine). Also I would be interested in having an idea of the thermal losses from exhaust port to turbo. But hey maybe I'm just being "negative" I have my manifold before I bought I worked out all of the above and I'm happy. You can all spend your money as you see fit. If you can't be bothered to question things that's fine I can't be bothered to explain.

To his credit I bet Bogdan's manifolds have far more design and analysis than any of the Ebay manifolds have put into them.

 

[red reading]

I only made the comment as if it's a proper group buy then someone should surely vet the technical merit of the product. I'm not knocking the fabrication skills or the durability of the manifolds and I have always had the upmost admiration for Bogdan's welding (although I'd love to know if the warranty is valid for cars with anti-lag!). But I think a few questions need to asked, as it appears the designs are based on simple pipe flow calculations. Comments such as "Equal length is not so important how the number of bends on each runner is." would lead me to have concerns as this is clearly only considering steady state effects. There is no point in having a tubular manifold if it's not going to be equal length, as the result is uneven back pressure across the cylinders and the loss of most of the benefits over a log design.

The sort questions I would be asking are what are the L/D ratio of the runners and was this taken from the head or the valve, how was the runner length chosen and what assumptions regarding valve timing, rpm, turbine inlet temp and pressure were made, what loss modeling was used the bends and does the design avoid reversion and if it occurs between what rev range (reversion can be a very bad thing - just ask any skyline owner that had a ceramic turbine fail and sucked back into the engine). Also I would be interested in having an idea of the thermal losses from exhaust port to turbo. But hey maybe I'm just being "negative" I have my manifold before I bought I worked out all of the above and I'm happy. You can all spend your money as you see fit. If you can't be bothered to question things that's fine I can't be bothered to explain.

To his credit I bet Bogdan's manifolds have far more design and analysis than any of the Ebay manifolds have put into them.

Ooooo ya clever git............who's going to ask what reversion is then?

 

[shroom]

Makaveli dont forget we are talking about a pulsar here, any thought into things costs money and 90
% of owners dont spend money they just waste it lol,

 

[PobodY]

Ooooo ya clever git............who's going to ask what reversion is then?

I'm going to keep my mouth shut and let everyone think I'm an idiot... rather than start typing and prove it.

 

[warpspeed]

haha good plan!

 

[STU666V]

I only made the comment as if it's a proper group buy then someone should surely vet the technical merit of the product. I'm not knocking the fabrication skills or the durability of the manifolds and I have always had the upmost admiration for Bogdan's welding (although I'd love to know if the warranty is valid for cars with anti-lag!). But I think a few questions need to asked, as it appears the designs are based on simple pipe flow calculations. Comments such as "Equal length is not so important how the number of bends on each runner is." would lead me to have concerns as this is clearly only considering steady state effects. There is no point in having a tubular manifold if it's not going to be equal length, as the result is uneven back pressure across the cylinders and the loss of most of the benefits over a log design.

The sort questions I would be asking are what are the L/D ratio of the runners and was this taken from the head or the valve, how was the runner length chosen and what assumptions regarding valve timing, rpm, turbine inlet temp and pressure were made, what loss modeling was used the bends and does the design avoid reversion and if it occurs between what rev range (reversion can be a very bad thing - just ask any skyline owner that had a ceramic turbine fail and sucked back into the engine). Also I would be interested in having an idea of the thermal losses from exhaust port to turbo. But hey maybe I'm just being "negative" I have my manifold before I bought I worked out all of the above and I'm happy. You can all spend your money as you see fit. If you can't be bothered to question things that's fine I can't be bothered to explain.

To his credit I bet Bogdan's manifolds have far more design and analysis than any of the Ebay manifolds have put into them.

Thats just what i was going to ask! but lost the internet on the boat! Haha

 

[STU666V]

• REVERSION ​

Reversion is simply the exhaust gases momentarily flowing backwards during the overlap phase of the camshaft at low cycling rates. During the overlap phase the engine is on the exhaust stroke and the piston is pushing out the last of the exhaust gases. Prior to reaching top dead center the intake valve begins to open. At low cycling rates the intake charge and the exiting exhaust pulse have yet created any momentum. Thus the piston pushes some spent exhaust gas into the intake manifold. This is why engines with big camshafts idle and sound radical. The exhaust pulses shoot up into intake manifold causing a major disturbance. The cylinders receive an uneven mixture of air, fuel and spent exhaust gas. The piston then reaches top dead center and begins the intake stroke. At this point both valves are open, in fact the exhaust valve in some cases may not shut for another 50 degrees of crank rotation. During this 50 degrees of crank rotation the piston literally draws from both the intake and exhaust valves causing the exhaust gases will momentarily reverse. At high cycling rates the inertia of the incoming intake charge and the out going exhaust pulse keep the gases flowing in the proper direction. Not a problem until you add water into the exhaust stream. Concerning headers, reversion can be severe enough to add water to oil (milky oil), rust valve seats, even stall the engine. This effect only happens at idle, but engines encounter their greatest reversion pulse at shut down.
For this reason Lightning Performance Marine has developed guide lines to help you decide what options to add when considering an exhaust system.
Our guide lines are based on a 454 C.I. engine with a standard Mercury header and 8" long collector. The camshaft should be no larger than 240 deg. duration @ .050 lift. Lobe separation angle 112 degrees. Valve lift is not that much of a factor. These figures are just guide lines. Cubic inch displacement, valve size, connecting rod length, valve timing, etc. all have an effect on reversion.
THE ONLY TRUE TEST FOR REVERSION IS TO IDLE THE ENGINE WITH THE HEADERS ATTACHED AND WATER GOING THROUGH THEM, SHUT IT DOWN, REMOVE THE HEADERS AND IF YOU HAVE WATER RESIDUE LAYING IN THE EXHAUST PORTS, YOU HAVE REVERSION.
Lightning Performance Marine makes many options to reduce or totally eliminate reversion.

• ANTI REVERSION TIPS

1. Header selection The tip to header selection is to choose a design that will introduce water into the exhaust stream as late as possible. For example our 40340 header is actually made to replace a Mercury manifold with a 3" riser block. This header is 4" taller than a standard Mercury header plus it rocks forward 2" thus were able to add a 2" longer collector. If the height is not a concern you just added 6" of dry length to the header.
   
2. Collector selection If you have room to add dry collector length do it. Collectors are available in a variety of lengths.
   
3. Cubic inch displacement The tip here is simple, the bigger they are the harder they suck back. Either reduce the duration of the cam or start add some anti reversion options.
   
4. Camshaft selection With regards to headers the only thing your concerned about is how much piston movement in volume takes place while the exhaust valve is open on the intake stroke. A wide lobe separation angle actually advances the exhaust valve timing event which will close the exhaust valve sooner, but the down side is it also moves the horsepower and torque curve up the RPM range. Rhoades style bleed down lifters will deduce the cam duration by as much as 20 degrees. Available only in standard hydraulic these lifters are a great choice.
   
5. Connecting rods Marine engine builders rarely think of connecting rod ratios effecting reversion, but it does. A longer than stock connecting rod will make the piston dwell at the top during the overlap cycle thus less piston movement with regards to crank rotation.